flavan-3-ols are an effective chemical defense against ... · 1 article title: flavan-3-ols are an...

1

Article title: Flavan-3-ols are an Effective Chemical Defense against Rust 1

infection 2

3

Corresponding author: Almuth Hammerbacher, Department of Zoology and Entomology, 4

Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Private Bag 5

X20, Hatfield 0028, Pretoria, South Africa, Email: [email protected], Phone: 6

+27 12 460 3934, Fax: +27 12 460 3960 7

8

Research area: Biochemistry and Metabolism 9

10

Short title: Catechin and Proanthocyanidins are Antifungal Defenses in Poplar 11

12

Authors: Chhana Ullah,a Sybille B. Unsicker,a Christin Fellenberg,b C. Peter Constabel,b Axel 13

Schmidt,a Jonathan Gershenzon,a and Almuth Hammerbachera,c,1 14

15 aDepartment of Biochemistry, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, 16

07745 Jena, Germany; bDepartment of Biology, Centre for Forest Biology, University of 17

Victoria, Victoria, BC V8W 3N5, Canada; cDepartment of Microbiology and Plant Pathology, 18

Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria, South Africa; 19 1To whom correspondence should be directed. 20

21

One sentence summary: Black poplar synthesizes flavan-3-ols as anti-fungal defenses against 22

the foliar rust fungus (Melampsora larici-populina). 23

24

Author contributions: CU, SU, JG and AH designed the research. CU performed the 25

experiments and analyzed the data, assisted by AH. AS produced the transgenic black poplar 26

lines. CPC and CF produced the transgenic hybrid aspen lines and conducted inoculation 27

experiment with rust fungus M. aecidiodes. CU, JG and AH wrote the article. All authors read 28

and approved the manuscript. 29

30

Plant Physiology Preview. Published on October 25, 2017, as DOI:10.1104/pp.17.00842

Copyright 2017 by the American Society of Plant Biologists

www.plantphysiol.orgon March 18, 2020 - Published by Downloaded from Copyright © 2017 American Society of Plant Biologists. All rights reserved.

http://www.plantphysiol.org

2

Funding information: This work was supported by the Jena School for Microbial 31

Communication (JSMC) and the Max Planck Society (MPG). 32

33

ABSTRACT 34

Phenolic secondary metabolites are often thought to protect plants against attack by microbes but 35

their role in defense against pathogen infection in woody plants has not been comprehensively 36

investigated. We studied the biosynthesis, occurrence and anti-fungal activity of flavan-3-ols in 37

black poplar (Populus nigra L.), which include both monomers, such as catechin, and oligomers 38

known as proanthocyanidins (PAs). We identified and biochemically characterized three 39

leucoanthocyanidin reductases (LAR) and two anthocyanidin reductases (ANR) from P. nigra 40

involved in catalyzing the last steps of flavan-3-ol biosynthesis leading to the formation of 41

catechin [2,3-trans-(+)-flavan-3-ol] and epicatechin [2,3-cis-(-)-flavan-3-ol] respectively. Poplar 42

trees that were inoculated with the biotrophic rust fungus (Melampsora larici-populina) 43

accumulated higher amounts of catechin and PAs than uninfected trees. The de novo synthesized 44

catechin and PAs in the rust infected poplar leaves accumulated significantly at the site of fungal 45

infection in the lower epidermis. In planta concentrations of these compounds strongly inhibited 46

rust spore germination and reduced hyphal growth. Poplar genotypes with constitutively higher 47

levels of catechin and PAs as well as hybrid aspen overexpressing the MYB134 transcription 48

factor were more resistant to rust infection. Silencing PnMYB134, on the other hand, decreased 49

flavan-3-ol biosynthesis and increased susceptibility to rust infection. Taken together, our data 50

indicate that catechin and PAs are effective anti-fungal defenses in poplar against foliar rust 51

infection. 52

53

Keywords: plant-pathogen interactions, Populus nigra, phenolics, flavonoids, condensed tannins54



3

55

INTRODUCTION 56

Plant phenolics are a diversified group of secondary metabolites that serve as structural 57

components of plant cells, coloring agents of flowers and fruits, protection against biotic and 58

abiotic stresses and as important agents in human medicine (Treutter, 2005; Pereira et al., 2009; 59

Dixon, et al., 2013). Most of these compounds are derived from the aromatic amino acid 60

phenylalanine via the phenylpropanoid pathways. The major subclasses of phenylalanine-derived 61

phenolic compounds include the chalcones, flavones, flavonols, isoflavones, anthocyanidins, 62

proanthocyanidins, stilbenes, coumarins, furanocoumarins, hydroxycinnamic acids, monolignols 63

and lignans (Bennett and Wallsgrove, 1994; Kutchan et al., 2015). 64

65

Proanthocyanidins (PAs, also known as condensed tannins) are phenolics that are major 66

end products of the flavonoid biosynthetic pathway in the tissues of many terrestrial plant 67

species. The building blocks of oligomeric or polymeric PAs are commonly known as flavan-3-68

ols which have the characteristic C6-C3-C6 flavonoid backbone (Dixon, 2005). Flavan-3-ols 69

differ structurally from other flavonoids by having a nearly saturated C ring with an additional 70

hydroxyl group on the 3-position which as a chiral center gives rise to cis- and trans-forms of the 71

basic PA-forming units, 2,3-trans-(+)-catechin or 2,3-cis-(-)-epicatechin. The structural diversity 72

of PAs is further increased by the hydroxylation patterns of the B-ring (mono-, di- or tri-73

hydroxylation) and the degree of polymerization (up to more than 100 flavan-3-ol units) 74

(Ferreira and Slade, 2002; Hammerbacher et al., 2014). 75

76

The biosynthesis of flavan-3-ols and PAs has been studied in many plant species (Xie et 77

al., 2004; Bogs et al., 2005; Paolocci et al., 2007; Pang et al., 2013). The last steps of monomer 78

biosynthesis are catalyzed by two distinct enzymes. For the biosynthesis of 2,3-trans-(±)-flavan-79

3-ols (e.g. catechin), leucoanthocyanidins are reduced directly to the corresponding flavan-3-ol 80

(Tanner et al., 2003; Pang et al., 2013) by leucoanthocyanidin reductase (LAR). For the 81

biosynthesis of the 2,3-cis-type compounds (e.g. epicatechin), leucoanthocyanidins are converted 82

to anthocyanidins by anthocyanidin synthase (ANS) and then reduced by anthocyanidin 83

reductase (ANR) to make the corresponding 2,3-cis-flavan-3-ol (Xie et al., 2004). Recently, 84

LAR has also been shown to convert 4β-(S-cysteinyl)-epicatechin to free epicatechin in 85



4

Medicago truncatula and so plays an important role in regulating the length of PA polymers (Liu 86

et al., 2016). Both LAR and ANR are NADPH/NADH-dependent isoflavone-like reductases 87

belonging to the reductase-epimerase-dehydrogenase superfamily. 88

89

Both monomeric flavan-3-ols and PAs have been shown to contribute to plant defense 90

against microbial pathogens, insects and mammalian herbivores, as well as abiotic stresses 91

(reviewed by Dixon, 2005). Especially in woody plant species, catechin and PAs accumulate 92

upon pathogen infection and are thought to represent antimicrobial defenses (Barry et al., 2002; 93

Danielsson et al., 2011; Hammerbacher et al., 2014; Miranda et al., 2007; Nemesio-Gorriz et al., 94

2016). In support of this hypothesis, pre-treatment of roots with catechin induced systemic 95

resistance in shoots against the bacterial pathogen Pseudomonas syringae (Prithiviraj et al., 96

2007). Catechin has also been shown to quench bacterial quorum-sensing (QS) and biofilm 97

formation by inhibiting the QS-regulated gene expression involved in the production of virulence 98

factors (Vandeputte et al., 2010). Furthermore, catechin and epicatechin have been reported to 99

inhibit appressorial melanization of the necrotrophic fungus Colletotrichum kahawae causing 100

coffee-berry disease (Chen et al., 2006). However, strong evidence for a defensive function, 101

including in vitro and in planta studies are lacking for most systems. In addition, the spatial and 102

temporal dynamics of monomeric flavan-3-ol and PA accumulation in planta upon challenge 103

with fungal pathogens are not well understood. 104

105

Poplars (Populus spp.) are widely distributed tree species in the Northern hemisphere and 106

are considered good model organisms for woody plant research due to the availability of the 107

complete genome of Populus trichocarpa (Torr. & Gray) (black cottonwood) and established 108

platforms for genetic, molecular and biochemical research (Tuskan et al., 2006; Jansson and 109

Douglas, 2007). Poplar species are also economically important plantation trees due to their fast 110

growth, use in bioenergy, pulping and plywood production (Stanturf et al. 2001; Berguson et al. 111

2010) and role in phytoremediation of contaminated soil as well as municipal landfills (Schnoor 112

et al., 1995; Robinson et al., 2000). However, under natural conditions poplars are challenged by 113

a plethora of microbial pathogens (Newcombe et al., 2001). 114

115



5

Poplar rust fungi (Melampsora spp.) are the most devastating foliar fungal pathogens of 116

poplar and cause substantial losses in biomass production (Newcombe et al., 2001; Duplessis et 117

al., 2009). The two most destructive species of rust fungi infecting poplar plantations in North 118

America and Eurasia are M. medusae and M. larici-populina, respectively (Newcombe, 1996). 119

Melampsora species are obligate biotrophic fungi, belonging to the phylum Basidiomycota 120

(Pucciniomycotina, Pucciniomycetes, Pucciniales, Melampsoraceae). Their heteroecious life 121

cycle is very complex such that two completely different hosts (poplar and larch) and five 122

different spore-types (uredinia, telia, basidia, pycnia and aecia) are required for completion of the 123

life cycle. The asexual stage of these fungi occurs during early spring and summer on poplar and 124

is characterized by formation of yellow pustules on the leaves (uredinia) that produce copious 125

amounts of asexual urediniospores with which the fungus can infect new poplar hosts (reviewed 126

by Hacquard et al., 2011). With the availability of the complete genomes of both poplar (Tuskan 127

et al., 2006) and the rust fungus (Duplessis et al., 2011), this system has become an important 128

resource for studying plant-pathogen interactions. 129

130

Poplars synthesize and accumulate several classes of phenolic metabolites, including 131

salicinoids (phenolic glycosides), anthocyanins, PAs and low molecular weight phenolic acids 132

and their esters in leaves, stems and roots (Pearl and Darling, 1971; Palo, 1984; Tsai et al., 2006; 133

Boeckler et al., 2011). Salicinoids and PAs are generally the most abundant secondary 134

metabolites and together can make up to 30-35% of leaf dry weight (Lindroth and Hwang, 1996; 135

Tsai et al., 2006). Although very little is known about the biosynthesis of salicinoids, advances 136

have been made on research into PA biosynthesis in poplar. Three candidate genes encoding 137

LARs and two genes encoding ANRs were discovered in the P. trichocarpa genome (Tsai et al., 138

2006), and a subset of these genes has been genetically characterized in P. tomentosa (Yuan et 139

al., 2012; Wang et al., 2013). Furthermore, biosynthesis and accumulation of PAs have been 140

shown to be transcriptionally regulated either positively or negatively by MYB transcription 141

factors which have been characterized in poplar (Mellway et al., 2009; Yoshida et al., 2015; 142

Wang et al., 2017). However, biochemical characterization of poplar LAR or ANR proteins 143

catalyzing the two different branches of flavan-3-ol biosynthesis, and regulatory studies of the 144

corresponding genes have not been attempted so far in black poplar. 145

146



6

Although PAs are constitutively present in poplar species, their biosynthesis can be up-147

regulated by insect herbivory and mechanical wounding (Peters and Constabel, 2002; Mellway et 148

al., 2009). The role of PAs in defense against leaf-chewing insects is controversial and these 149

substances have been frequently shown to be ineffective (Hemming and Lindroth, 1995; Ayres et 150

al., 1997; Boeckler et al., 2014). On the other hand, PAs might be an effective defense against 151

pathogen infection. In hybrid poplar, genes of the flavonoid pathway are activated 152

transcriptionally upon infection with the rust fungus M. medusae, leading to the accumulation of 153

PAs (Miranda et al., 2007). Overexpression of a PA biosynthetic gene PtrLAR3 in Chinese white 154

poplar (P. tomentosa Carr.) increased resistance against Marssonina brunnea causing leaf spot 155

(Yuan et al., 2012). However, further evidence is required to substantiate the function of flavan-156

3-ols in poplar defense against pathogens. 157

158

In this study we provide evidence that flavan-3-ols are effective chemical defenses in 159

poplar against foliar rust fungus infection. Catechin and PAs as well as the transcript abundances 160

of the three LAR and two ANR genes involved in their biosynthesis increased significantly upon 161

fungal infection of both stems and leaves of black poplar. We also show that these compounds 162

accumulate at the site of infection. In vitro assays using artificial medium amended with 163

physiologically relevant concentrations of catechin and PAs revealed that these compounds are 164

directly toxic to poplar pathogens. In planta infection assays using genetically manipulated 165

poplar as well as natural black poplar genotypes with different levels of flavan-3-ols further 166

supported the role of catechin and PAs in the defense of black poplar against pathogen attack. 167

168

169



7

RESULTS 170

Catechin and Proanthocyanidins (PAs) Accumulate in the Leaves of Black Poplar after 171

Rust Fungus Infection 172

To determine if there is any change in the contents of phenolic compounds in black 173

poplar (P. nigra) leaves upon fungal infection, a controlled infection experiment was conducted 174

on young clonal saplings (line NP1) using the rust fungus M. larici-populina. Poplar plants were 175

inoculated thoroughly by spraying with an aqueous suspension of rust spores, and in parallel 176

control plants were treated with water. Six fully expanded mature leaves from each rust-infected 177

or control plant were sampled and pooled together (Fig. 1A). The leaf extracts were analyzed by 178

high performance liquid chromatography coupled to a diode array detector or fluorescence 179

detector (HPLC- DAD/FLD) or to a tandem mass spectrometer (LC-MS/MS). 180

Catechin (2,3-trans-(+)-flavan-3-ol) accumulated in significantly higher amounts 181

(approximately 2.5- to 3-fold) in rust-infected leaves in comparison to uninfected control plants 182

from 3 to 21 days post inoculation (dpi) (ANOVA, p < 0.001, Fig. 1B). The isomeric epicatechin 183

(2,3-cis-(-)-flavan-3-ol) also accumulated in greater amounts in rust-infected leaves compared to 184

control leaves at 7 dpi (ANOVA, p < 0.001, Supplemental Fig. S1), but the concentration was 185

much lower than that of catechin. The concentrations of flavan-3-ol dimers, mainly PA-B1 [2,3-186

cis-(-)-epicatechin-(4β→8) - 2,3-trans-(+)-catechin], significantly increased 2.5- to 3-fold after 187

rust infection (ANOVA, p < 0.001, Fig. 1C). We detected and quantified PA oligomers 188

containing flavan-3-ol monomeric size units up to 8 and found that these also significantly 189

increased to a similar degree after rust infection (ANOVA, p < 0.001, Fig. 1D; Supplemental Fig. 190

S5). Furthermore, we analyzed the cell-wall-bound PAs from the residues after methanol and 191

acetone extractions using the acid butanol method (Porter et al., 1986). Interestingly, the 192

insoluble PAs also accumulated in higher amounts in rust-infected poplar leaves than the healthy 193

leaves over the course of infection (ANOVA, p < 0.001, Fig. 1E). Reductive hydrolysis of 194

soluble PAs into their respective monomeric units revealed that epicatechin and catechin levels 195

increased after rust infection (ANOVA, p < 0.001, Fig. 1F). 196

197

We quantified other major phenolics in black poplar by HPLC-DAD to determine 198

whether these compounds also accumulate upon rust infection. The concentration of the 199

flavonoid quercetrin increased significantly after rust infection, whereas rutin (quercetin-3-O-200



8

glucoside-rhamnoside) significantly decreased (ANOVA, p < 0.001, Supplemental Fig. S1). 201



9

Black poplars are well known to synthesize high amounts of salicinoids (Boeckler et al., 2013) 202

which we quantified using HPLC-DAD. Salicin, the simplest salicinoid, accumulated in greater 203

amounts in P. nigra leaves after rust infection at 21 dpi compared to uninfected control leaves 204

(ANOVA, p = 0.017, Supplemental Fig. S1). However, concentrations of the other salicinoids, 205

salicortin, homaloside D and tremulacin, decreased in the rust-infected leaves in comparison to 206

the leaves of corresponding control plants (ANOVA, p ≤ 0.005 for all salicinoids, Supplemental 207

Fig. S1). 208

209

To determine the degree of colonization of the fungus in black poplar leaves, we 210

quantified the mRNA levels of the rust actin gene and normalized this quantity to the mRNA 211

levels of poplar Ubiquitin (PtUBQ). The abundance of rust fungus in the leaves was low until 3 212

dpi, and then increased exponentially at 7 dpi coinciding with the appearance of visible 213

symptoms (rust uredia) on the lower surfaces of infected leaves (ANOVA, p < 0.001, Fig. 1G). 214

215

Three LAR and two ANR Enzymes Catalyze the Last Steps of Flavan-3-ol Biosynthesis in 216

Black Poplar 217

To better understand the biosynthesis of flavan-3-ols in black poplar, we utilized the 218

genome of P. trichocarpa to identify genes involved in the last steps of the pathway which are 219

specific to flavan-3-ol formation. As previously identified by Tsai et al. (2006) we found three 220

LAR and two ANR candidate protein sequences from P. trichocarpa in GenBank and the 221

Populus trichocarpa v3.0 database (Phytozome 11, https://phytozome.jgi.doe.gov/pz/portal.html) 222

using blast searches targeting proteome data. The coding sequences of putative PtLAR and 223

PtANR genes were retrieved from Phytozome, and open reading frames identified and amplified 224

from P. nigra cDNA using primers designed from P. trichocarpa mRNA sequences. All three 225

LAR and the two ANR genes are located on separate chromosomes in the P. trichocarpa genome. 226

To investigate the biochemical functions of PnLARs and PnANRs, the genes were cloned and 227

heterologously expressed in Escherichia coli. To determine LAR enzyme activity, each PnLAR 228

and an apple dihydroflavonol reductase (DFR) gene were co-expressed in E. coli cells, and the 229

catalytic activities of the proteins were determined by incubating crude protein extracts with the 230

substrate taxifolin (a dihydroflavonol) and NADPH. The DFR protein converted taxifolin to 231

leucocyanidin which was then used by all three PnLAR enzymes to make the final product 232



10

catechin (Fig. 2B). To characterize ANR enzymes, heterologously expressed PnANR was mixed 233

with an expressed Petunia anthocyanin synthase (ANS) and incubated with the substrate catechin 234

and known cofactors. The Petunia ANS converted catechin to cyanidin which was then used as a 235

substrate by both PnANR enzymes to form epicatechin (Fig. 2C). 236



11

237

To determine the evolutionary relationships of the LAR and ANR enzymes from black 238

poplar and other plant species, a maximum-likelihood tree was constructed (Fig. 3). The closely 239

related protein sequence PtrDFR (an ortholog of apple DFR) was included in the tree. The 240

consensus tree was noticeably bifurcated with two clades: one for all the LARs and the other for 241

all the ANRs. The DFR was more closely related to the ANRs. Within each LAR and ANR 242

cluster, enzymes from gymnosperms and angiosperms clustered separately. The PnLAR3 243

characterized in this study was closely related to TcLAR (Theobroma cacao) with 57% identity 244

at the amino acid level, while PnLAR1 and PnLAR2 clustered with LAR proteins from a range 245

of plant species. LAR1 and LAR2 shared 84% similarity in their sequences at the amino acid 246

level and may have resulted from a recent duplication. Within the ANR cluster, both PnANR1 247

and PnANR2 clustered together and showed the greatest similarities with MtANR1 (Medicago 248

truncatula) and LcANR1 (Lotus corniculatus). PnANR1 and PnANR2 share 62% and 64% 249

similarity with Arabidopsis AtANR (AtBAN), respectively, on the basis of their deduced amino 250

acid sequences. 251

252

To gain a broader understanding of flavan-3-ol biosynthesis in black poplar at the organ 253

level, we analyzed the constitutive levels of monomeric flavan-3-ols and PAs in leaves, petioles, 254

stems and roots of six month old black poplar saplings (Supplemental Fig. S2). Concentrations of 255

catechin, PA dimers and polymers were lower in the leaf lamina than in the stems and roots. Leaf 256

petioles also contained significantly higher levels of catechin and PAs than the leaf lamina 257

(Supplemental Fig. S2). The concentration of epicatechin was very low in all parts of the plant 258

(Supplemental Fig. S2). Steady-state transcript levels of the three PnLAR and two PnANR genes 259

were also measured in different tissues. Transcript levels of PnLARs were 2-3-fold higher in 260

fully expanded mature leaves and stems in comparison with expanding young leaf laminae and 261

roots (Supplemental Fig. S3). While higher levels of PnANR1 transcript were found in all leaf 262

laminae than other tissues (Supplemental Fig. S3), the PnANR2 was expressed at higher levels in 263

fully expanded mature leaves and older stems (Supplemental Fig. S3). 264

265

Increases in Catechin and PA in Rust-Infected Black Poplar Leaves are Transcriptionally 266

Regulated 267



12

To determine if the accumulation of catechin and PAs during rust infection is also 268

transcriptionally regulated in a wild P. nigra clone, we measured the relative transcript 269

abundances of the PnLAR and PnANR biosynthetic genes characterized in this study as well as 270

PnMYB-134, a R2R3 domain transcription factor known to regulate PA biosynthesis in poplar 271

(Mellway et al., 2009), by qRT-PCR from the same samples used to measure phenolics. The 272

gene expression data revealed that transcription of the three PnLAR genes, the two PnANR genes, 273

and the MYB134 gene was activated after rust fungus infection (ANOVA, p < 0.001 for all 274

genes, Fig. 4). PnLAR and PnANR transcripts increased 3 to 4-fold in the rust infected leaves at 7 275

days post inoculation compared to the corresponding control plants (Fig. 4A to 4E). 276

Interestingly, the transcription factor PnMYB134 responded quickly after 6 hours with the 277

highest expression at 7 dpi, which is a faster response than for the genes encoding the enzymes 278

of flavan-3-ol biosynthesis (Fig. 4F). 279



13

280

Poplar Genotypes with Constitutively Higher Levels of Catechin and PAs are More 281

Resistant to Rust Fungus Infection 282

To elucidate the defensive role of catechin and PAs in planta during poplar-rust 283

interactions, we tested different poplar genotypes for their susceptibility to M. larici-populina 284

infection during June to October, 2014. From this preliminary screening, five genotypes ranging 285



14

from highly susceptible to moderately resistant were then selected for controlled inoculation 286

under natural environmental conditions in summer (June-August) 2015 (Supplemental Table S1). 287

288

The constitutive levels of catechin were at least 2-3 times higher in the moderately 289

resistant genotypes (Dorn, Kew and Bla) in comparison to the highly susceptible genotypes (NP1 290

and Leip) (ANOVA, p < 0.001, Fig. 5A). All genotypes showed increased levels of catechin in 291

leaves after rust infection (ANOVA, p = 0.002, Fig. 5A). The levels of PAs in leaves were also 292

significantly different among the genotypes (ANOVA, p < 0.001) and followed the same trend 293

observed for catechin concentration with moderately resistant genotypes containing higher levels 294

than sensitive genotypes before rust infection with an increase in concentration in response to 295

rust infection (Fig. 5B to 5C). Cell wall-bound insoluble PAs also accumulated to higher levels 296

in resistant clones compared to the susceptible clones (ANOVA, p < 0.001, Fig. 5D). The minor 297

flavan-3-ols, epicatechin and gallocatechin, did not change significantly after rust infection 298

(Supplemental Fig. S6). While higher basal levels of epicatechin were found in the susceptible 299

NP1 and Leip genotypes (Supplemental Fig. S6), more constitutive gallocatechins were found in 300

the resistant Dorn, Kew and Bla genotypes (Supplemental Fig. S6). After acid hydrolysis of PAs, 301

approximately 20-30% more gallocatechin and epigallocatechin were recovered in samples taken 302

from the moderately resistant genotypes (Supplemental Fig. S7). Total amounts of flavan-3-ol 303

monomers increased approximately 25% in all genotypes after rust infection 8 days post 304

inoculation (Supplemental Fig. S7). To confirm the resistance of the poplar genotypes to rust 305

fungus infection in this study, we quantified relative growth of the fungus in rust-infected 306

samples from all five genotypes. The highest rust colonization was found in the genotype NP1 307

whereas the lowest was found in Kew and Bla genotypes (ANOVA, p < 0.001, Fig. 5E). 308

Transcript levels of two LARs were around two-fold lower in the susceptible genotype NP1 than 309

the resistant genotypes with a significant induction after rust infection. The level of ANR 310

transcripts was also lower in the NP1 and Dorn genotypes than in all other genotypes 311

(Supplemental Fig. S7). 312

313

To compare the detrimental effects of rust infection in different poplar genotypes, we 314

allowed a subset of plants of the same age from each genotype to grow under natural conditions 315

for a complete season in 2015. Susceptible, low flavan-3-ol plants were heavily infected and 316



15

defoliated by rust damage during mid-summer to early-autumn (July-September), but plants of 317

the high flavan-3-ol, moderately resistant genotypes were healthy until November. After 318

seasonal leaf drop in winter, we measured biomass gain in all genotypes. The low flavan-3-ol 319



16

genotypes gained 20-30% more biomass than the resistant genotypes containing high flavan-3-320

ols (ANOVA, p < 0.001, Fig. 5F). Our results indicated that rust infection can be detrimental to 321

biomass gain over a full growing season, but high flavan-3-ol levels presumably mediate 322

resistance and prevent any decrease in biomass. 323

324

Catechin and PAs are Toxic to M. larici-populina in vitro 325

To investigate the direct antifungal activities of rust-induced levels of catechin and PAs, 326

an in vitro bioassay was developed for the biotrophic rust fungus M. larici-populina 327

(Supplemental Fig. S9). The spore germination and hyphal growth in medium containing the test 328

compounds were monitored under an inverted light microscope. The spores started to germinate 329

after 4-5 hours of incubation in control medium, but germination was strongly inhibited in 330

medium supplemented with catechin or PAs (Fig. 6A to 6B). After 24 h, germinated spores on 331

control slides were highly branched whereas mycelial branching was inhibited on the catechin or 332

PA supplemented slides (Fig. 6C to 6D). The germination percentage in control medium was 333

89.3% while catechin and PA supplementation significantly reduced germination to 21.1% and 334

13.3% respectively (ANOVA, p < 0.001, Fig. 6E). The average hyphal length on the control 335

slides was 60 µm while the lengths in the catechin and PA treatments were 17 to 20 µm 336

respectively (Fig. 6F). Decreased spore germination, reduced hyphal length and decreased 337

branching on catechin- and PA-supplemented slides indicate that flavan-3-ols are directly toxic 338

to the poplar rust fungus. We also tested different concentrations of catechin and PAs on rust 339

spore germination in vitro. Both catechin and PAs inhibited spore germination at 0.25 mg mL-1 340

but significant inhibition was only observed from 0.5 mg mL-1 (Supplemental Fig. S10). 341

Furthermore, we tested the anti-fungal activity of epicatechin, salicin, naringenin and quercetrin 342

against M. larici-populina. Naringenin inhibited spore germination, but the other compounds did 343

not show any effect on rust spore germination in vitro (Supplemental Fig. S10). 344

345

Overexpression of the MYB-134 Transcription Factor in Hybird Aspen Increased Flavan-3-346

ol Levels and Reduced Rust Susceptibility 347

The poplar MYB134 gene encodes an R2R3 MYB transcription factor, a positive 348

regulator of PAs in poplar. MYB134 overexpression in transgenic Populus leads to a strong 349

accumulation of PAs and catechin, but anthocyanins and other flavonoids are minimally affected 350



17

(Mellway et al., 2009). To directly test the effects of this over-accumulation of flavan-3-ols and 351

PAs on Melampsora resistance, we propagated three previously characterized P. tremula x alba 352

MYB134-overexpressing lines and inoculated these with Melampsora aecidiodes, a closely 353

related poplar rust that infects this hybrid. As expected, concentrations of catechin, PA dimers 354

and PA oligomers were enhanced and up to 3-8 fold higher in the MYB134 overexpressing lines 355



18

(ANOVA, p < 0.01, Fig. 7A to 7C), and Myb134 expression was 4-16 fold higher compared to 356

the wild type (ANOVA, p < 0.01, Fig. 7D). To determine rust colonization in the transgenic lines 357

and controls, we quantified Melampsora growth using qRT-PCR. Growth of the rust fungus M. 358

aecidiodes was significantly reduced in the MYB134- overexpressing lines in comparison with 359

wild type (ANOVA, p = 0.002, Fig. 7E), and roughly inversely proportional to catechin and PA 360

concentrations. 361

362



19

RNAi-Mediated Knockdown of MYB-134 Transcription Factor in Black Poplar 363

Downregulates Catechin and PA Biosynthesis, and Leads to Increased Rust Susceptibility 364

To complement these findings in black poplar, a native host of the rust fungus M. larici-365

populina, we down-regulated the MYB-134 gene in this species (P. nigra NP1) by RNA-366

interference to reduce the biosynthesis of flavan-3-ols. We obtained two independent transgenic 367

lines with lower flavan-3-ol monomer and PA levels. Transcript abundances of MYB134 in the 368

MYB-RNAi lines were significantly lower than in the controls (ANOVA, p = 0.006, Fig. 8D). 369

The concentrations of catechin, PA dimers and oligomers were approximately 40-50 % lower in 370

the RNAi lines in comparison with the vector control and wild type plants (ANOVA, p < 0.001, 371

Fig. 8A to 8C). The colonization of infected leaves by the rust fungus was up to 50% higher in 372

the two PnMYB134-RNAi lines compared to the vector control and wild-type plants (ANOVA, p 373

= 0.003, Fig. 8E). Epicatechin and naringenin concentrations were also significantly lower in the 374

PnMYB134-silenced lines (ANOVA, p < 0.001) but quercetrin did not change (p = 0.92). The 375

concentrations of the salicinoids such as salicin (p < 0.001), salicortin (p = 0.02) and tremulacin 376

(p = 0.015) slightly increased in the transgenic lines but homaloside D (p = 0.38) did not change 377

significantly (Supplemental Fig. S11). 378

379

Localization of Catechin and PAs at the Site of Rust Infection in Poplar Leaves 380

During compatible interactions in poplar hosts, rust spores germinate within 6-12 hours 381

after inoculation and establish an intercellular mycelial network within 2-4 days without any 382

visible symptoms (Hacquard et al., 2011). To better understand the role of catechin and PAs 383

against rust infection, we studied their localization in poplar leaves. Tissue-specific localization 384

of PAs was shown in many plant species by staining with 4-dimethylaminocinnamaldehyde 385

(DMACA) which produces a blue color (Kao et al., 2002; Abeynayake et al., 2011; Jun et al., 386

2015). Histochemical staining with DMACA revealed that catechin and PAs were densely 387

localized in the upper and lower epidermal layers and vascular bundles of the leaf in rust-388

resistant poplar genotypes (Fig. 9C to 9E). In comparison, a low level of staining was observed 389

in the susceptible genotypes NP1 and Leip (Fig. 9A to 9B). After infection with rust fungus, the 390

pattern of flavan-3-ol localization in the leaf changed, with more staining observed in the lower 391

epidermis and near to stomata (site of fungal invasion) and parenchyma cells (Fig. 9G to 9K). 392

Staining of leaf petioles from a susceptible genotype revealed that catechin and PAs in this tissue 393



20

were also localized in the epidermis and vascular bundles (Fig. 9F and 9L). Darker staining was 394

observed in the epidermal layer of rust infected petioles as well (Fig.9L). Taken together 395

histochemical staining revealed that catechin and PAs are mainly localized in the epidermis of 396

poplar leaf laminae and accumulate at the site of rust infection. Since poplar synthesizes a variety 397

of salicinoids and flavonoid-derived compounds, we tested the specificity of the DMACA. We 398

found that DMACA was very specific to flavan-3-ol monomers and PAs and did not react with 399

other major poplar phenolics (Supplemental Fig. S12). 400



21

401

402



22

403



23

DISCUSSION 404

Poplars synthesize a range of ecologically important secondary metabolites including 405

volatile organic compounds, such as terpenoids and nitrogenous compounds (Irmisch et al., 406

2013; Clavijo McCormick et al. 2014), as well as high quantities of phenolic metabolites 407

including salicinoids, flavonoids, proanthocyanidins (PAs) and hydroxycinnamate derivatives 408

(Tsai et al., 2006; Miranda et al., 2007; Boeckler et al., 2011; Yuan et al., 2012). Although the 409

biosynthesis and anti-herbivore activity of these compounds have recently come under close 410

scrutiny (Barbehenn and Constabel, 2011; Irmisch et al., 2013; Boeckler et al., 2013; Irmisch et 411

al., 2014; Boeckler et al., 2014), it is still not known if any are effective defenses against 412

pathogens of various life-styles. 413

414

Because chemical defense against plant pathogens has been mostly studied in cultivated 415

rather than wild species and in herbaceous rather than woody plants, we chose to investigate a 416

wild, woody host, black poplar, during its interaction with a foliar rust fungus commonly 417

observed in poplar floodplain forests in Europe. During this study, we assembled comprehensive 418

in planta evidence showing that monomeric (catechin) and polymeric (PAs) flavan-3-ols are 419

chemical defenses in poplar against poplar rust (Melampsora spp). Furthermore, we 420

demonstrated that these compounds accumulate preferentially at the site of fungal infection and 421

are directly toxic to this obligate biotrophic fungus at physiological concentrations. 422

423

Concentrations of Both Monomeric (Catechin) and Polymeric (PAs) Flavan-3-ols Increase 424

in Poplar after Rust Infection 425

Upon infection with the biotrophic rust fungus M. larici-populina, increased levels of 426

catechin and PAs were observed in rust-infected leaf laminae over the course of infection. The 427

isomeric form of catechin, known as (-)-epicatechin, increased in leaves after rust infection. 428

Among the other flavonoids commonly produced by poplar, quercetin increased in rust infected 429

leaves at the later stages of infection. These results are in agreement with previous studies in 430

poplar which showed that several flavonoid biosynthetic genes are transcriptionally activated in 431

poplar after rust colonization especially during the sporulation phase (Miranda et al., 2007; 432

Azaiez et al., 2009). Studies also demonstrated that biosynthesis of flavan-3-ols and PAs 433

increased after infection by fungal endophytes in poplar (Pfabel et al., 2012) as well as after 434



24

infection by pathogenic fungi in other plant species such as bilberry (Koskimäki, et al., 2009) 435

and Fagus crenata (Yamaji and Ichihara, 2012). Increased accumulation of flavan-3-ols has also 436

been recorded in Norway spruce during infection by necrotrophic fungi (Danielsson, et al., 2011; 437

Hammerbacher, et al., 2014). A range of plants, including poplar, therefore respond to pathogen 438

attack by accumulating both monomeric flavan-3-ols and PAs. 439

440

However, not all phenolics increase after pathogen infection. Salicinoids, an abundant 441

class of phenolics in poplar leaves that are known to defend against herbivores (Boeckler et al., 442

2011), decreased after rust infection, except for salicin which was slightly induced at the later 443

stages of infection. Salicinoids are thus not likely to be deployed by poplar for pathogen defense. 444

They might decline because of their metabolism by the fungus as a potential food source; the 445

sugar moiety in particular could be cleaved and assimilated by the pathogen (Hammerbacher et 446

al., 2013). A more likely explanation, however, is that lower levels of salicinoids in rust-infected 447

leaves result from elevated flavan-3-ol biosynthesis which was previously shown to reduce 448

salicinoid biosynthesis. Up-regulation of PA biosynthesis by over-expressing the transcription 449

factor MYB134 led to lower salicinoid content in hybrid poplar (Mellway, et al., 2009; Kosonen 450

et al., 2012; Boeckler et al., 2014). In the absence of fungal infection or other biotic stresses, 451

there are typically no dramatic differences in flavan-3-ol or salicinoid concentrations between 452

young expanding and fully expanded mature leaves (Supplemental Fig. S2 and S4) (Massad et 453

al., 2014), but this generalization does not apply after herbivore or pathogen attack. In line with 454

previous studies, our phenolic measurements suggest that there is a trade-off between flavan-3-ol 455

(catechin and PAs) versus salicinoid biosynthesis in poplar leaves (Boeckler et al., 2014), 456

implying a trade-off between anti-pathogen and anti-herbivore defense. 457

458

Transcripts of Flavan-3-ol Biosynthetic Genes Increase in Response to Fungal Infection 459

The biosynthesis of flavan-3-ols has been well characterized in many plant species both 460

genetically and biochemically. Two distinct enzymes, LAR and ANR, are involved in catalyzing 461

the last steps of the pathway to flavan-3-ol monomers in PA-producing plants (Bogs et al., 2005; 462

Pang et al., 2013; Liao et al., 2015). Genes encoding LAR and ANR can occur as single genes 463

for example in Arabidopsis thaliana (Xie et al., 2004) or as multi-gene families, for example in 464

grapevine and tea (Bogs et al., 2005; Pang et al., 2013). Analysis of the P. trichocarpa genome 465



25

revealed 3 loci encoding LAR proteins and two loci encoding ANR proteins. This is more than 466

the two PtLAR and one PtANR (Yuan et al., 2012; Wang et al., 2013) which were previously 467

reported and genetically characterized in P. trichocarpa. We confirmed the enzymatic activity of 468

the proteins encoded by all loci by heterologous expression and in vitro enzyme assays and 469

showed that they are likely involved in the catalysis of the last steps of flavan-3-ol biosynthesis 470

in native black poplar (P. nigra). Our phylogenetic analysis shows that ANRs and LARs are two 471

distinct classes of enzymes, and that DFR is more related to ANRs than LARs. Similar 472

evolutionary relationships for ANR and LAR proteins were shown by other authors (Pang et al., 473

2013; Wang et al., 2013). 474

475

Transcript levels of all three PnLAR and two PnANR genes increased in rust-infected 476

black poplar leaves over the course of infection. Previous microarray data also demonstrated that 477

some of the genes of this pathway are transcriptionally induced in hybrid poplar after infection 478

with M. medusae (Miranda et al., 2007). As previously reported for hybrid poplar (Mellway et 479

al., 2009), the transcription factor PnMYB134, a positive regulator of PA biosynthesis, was also 480

transcriptionally induced and responded quickly after rust inoculation in our study. Our transcript 481

and metabolite analyses suggest that both LAR and ANR branches of flavan-3-ol biosynthesis 482

are transcriptionally activated upon rust infection. Monomeric catechin synthesized from the 483

LAR-branch is freely available and accumulated in black poplar while free ANR-dependent 484

epicatechin was only observed at very low concentrations. Recovery of epicatechin after 485

hydrolysis of PAs indicates that epicatechin might contribute to the extension of PA chains. 486

Similar mechanisms were also observed in grape and Norway spruce (Bogs et al., 2005; 487

Hammerbacher et al., 2014). 488

489

High Levels of Catechin and PAs are Associated with Resistance against Rust Fungus 490

Infection 491

Various constitutive and induced plant phenolic compounds are thought to contribute to 492

defense against microbial pathogens (Osbourn, 1996; Lattanzio et al., 2006), but not all 493

phenolics have this effect (Henriquez et al., 2012; Zhang et al., 2015). In order to determine if 494

flavan-3-ols have this function in planta, we screened five poplar genotypes for resistance 495

against rust infection and quantified their phenolic contents. Interestingly, genotypes moderately 496



26

resistant to rust infection had constitutively higher amounts of catechin and PAs in their leaves 497

than susceptible genotypes and substantially higher induced levels of these flavan-3-ols were 498

found after artificial inoculation with rust. Similar results have been shown in other woody plant 499

species. For example, crude extract from coffee cultivars resistant to coffee rust (Hemileia 500

vastatrix), which contained higher amounts of PAs in comparison to the extracts of susceptible 501

cultivars, was found more effective in inhibiting H. vastatrix uredospore germination (de 502

Colmenares et al., 1998). In addition, higher levels of constitutive and induced (+)-catechin were 503

found in a rust-resistant willow (Salix myrsinifolia) clone compared to levels in susceptible 504

clones (Hakulinen et al., 1999). Recently, Wang et al (2017) showed that P. tomentosa increased 505

its PA levels under elevated temperature as well as after infection by the necrotrophic fungus 506

Dothiorella gregaria. 507

508

To further explore the role of catechin and PAs as antifungal defenses in poplar, we 509

conducted an infection experiment using M. aecidiodes, in hybrid aspen (P. tremula X alba) 510

overexpressing the MYB134 transcription factor. Previously, this gene was characterized and 511

shown to be a positive regulator of PA biosynthesis in hybrid poplar and shown to be inducible 512

by biotic and abiotic stresses (Mellway et al., 2009). Rust susceptibility was significantly 513

reduced in MYB134-overexpressing lines accumulating higher levels of flavan-3-ols than the 514

wild type plants. To investigate the role of catechin in PAs in European black poplar and rust 515

system, we silenced the PnMYB134 transcription factor by RNAi in P. nigra NP1. We observed 516

a 40-60% reduction of monomeric flavan-3-ols and PAs in black poplar after silencing 517

PnMYB134. Silenced lines were more susceptible to rust fungus M. larici-populina in whole-518

plant infection trials (Fig. 8E), confirming the antifungal activity of these compounds in planta. 519

Overexpression of MYB134 in a hybrid poplar (P. tremula × tremuloides) caused a significant 520

reduction in salicinoid concentration (Mellway et al., 2009; Boeckler et al., 2014), but such a 521

trade-off was not observed in the MYB134 silenced P. nigra lines accumulating reduced levels 522

of flavan-3-ol and PAs. Silencing of flavan-3-ol biosynthesis is metabolically less costly for 523

poplar than constitutive overexpression or accumulation of flavan-3-ols under pathogen attack. 524

In agreement with our results, overexpression of a PA biosynthetic gene in P. tomentosa resulted 525

in increased resistance against necrotrophic fungi (Yuan et al., 2012, Wang et al., 2017). A 526

negative association between fungal endophyte communities and the levels of condensed tannin 527



27

was also shown in North American poplar species (Whitham et al. 2006). However, infection by 528

necrotrophic fungi was higher in P. angustifolia (Busby et al., 2013), which is known to 529

accumulate high amounts of condensed tannins (Whitham et al. 2006). These conflicting results 530

suggest that poplar-rust interactions are very complex and that other factors such as pathogen 531

virulence and non-phenolic defenses including surface immunity and effector-triggered 532

immunity might contribute to different outcomes of the infection process. Further investigation 533

is necessary using genotypes containing high PAs under natural conditions and also different rust 534

fungus strains. 535

536

Site and Magnitude of Flavan-3-ol Accumulation is Consistent with a Defensive Role 537

against Fungal Pathogens 538

Accumulation of flavan-3-ol monomers and PAs is often limited to specific tissue types 539

and developmental stages of plant organs. For example, in white clover (Trifolium repens) 540

flavan-3-ol monomers and PAs are localized in the epidermal layers of floral organs 541

(Abeynayake et al., 2011), while in Arabidopsis thaliana, PAs mainly accumulate in the seed 542

coat especially in the endothelial cells (Debeaujon et al., 2003). Biosynthesis and spatial 543

distribution of these compounds in specific tissues or organs might have ecological significance. 544

Our histochemical staining with DMACA revealed that flavan-3-ols are mainly localized in the 545

leaf epidermis and vascular tissues (Fig. 9). Moderately resistant genotypes that contained higher 546

levels of catechin and PAs had a more restricted localization of these compounds in the 547

epidermal layers compared to the susceptible genotypes. After rust infection, high amounts of 548

flavan-3-ols were also observed in the parenchyma cells. The epidermal localization of flavan-3-549

ols could provide a defensive barrier to early fungal colonization of the leaf. Dark PA staining 550

was also observed in the lower surface of the aspen leaves (Kao et al., 2002) and in hybrid poplar 551

stems infested by the galling aphid Phloeomyzus passerinii (Dardeau et al., 2014). 552

553

The effectiveness of an epidermal flavan-3-ol barrier depends on the inhibitory effect of 554

these compounds on rust development. Using a novel in vitro bioassay technique, we showed 555

that physiologically relevant concentrations of both catechin and PAs strongly inhibited rust 556

spore germination and reduced hyphal growth. However, epicatechin did not show antifungal 557

activity even at a 10 times higher concentration than found in poplar leaves (Supplemental Fig. 558



28

S9) although this compound is an extender unit in PA chains (Fig. 1F). Our data therefore clearly 559

show that catechin and PAs are active antifungal metabolites in poplar and might serve as an 560

effective chemical defense at the surface or in other tissues of the plant. 561

562

In conclusion, black poplar, a perennial woody species of Europe, Asia and northwestern 563

Africa, was shown to synthesize monomeric and polymeric flavan-3-ols as a phenolic defense 564

against the rust fungus M. larici-populina in concentrations demonstrated to have anti-fungal 565

activity in vitro at sites on the epidermis and in vascular tissue where they form a barrier to 566

fungal invasion. Rust resistant poplar genotypes used in this study constitutively accumulate 567

more flavan-3-ols than susceptible genotypes. Transgenic black poplar trees with reduced levels 568

of catechin and PAs were more susceptible. Future work is needed to investigate such topics as 569

the mode of action of flavan-3-ols on fungi, how infection triggers flavan-3-ol accumulation and 570

if other poplar metabolites act in defense against fungal infection. 571

572

573



29

METHODS 574

Plant Materials 575

Black poplar (P. nigra L. clone NP1) was propagated from stem cuttings and grown in 576

the greenhouse (22°C day temperature and 19°C night temperature, 60% relative humidity, 577

16h/8h light/dark cycle) in 2L pots having a 1:1 mixture of sand and soil (Klasmann potting 578

substrate; Klasmann-Deilmann, Geeste, Germany). Other poplar genotypes were supplied by the 579

Northwest German Forest Research Station (Nordwestdeutsche Forstliche Versuchsanstalt) in 580

Hann. Münden in 2014 as stem cuttings. Plants were regenerated under greenhouse conditions 581

and subsequently multiplied in large quantities. The transgenic black poplar plants used in this 582

study were amplified by micropropagation as described by Irmisch et al. (2013), and then 583

multiplied by stem cuttings. Transgenic hybrid aspen (P. tremula × alba INRA 717-1-B4) were 584

grown and maintained as described by Mellway et al. (2009). Plants with a height of 585

approximately 80-100 cm were used for inoculation with fungi. Some plants from each genotype 586

were grown outside the greenhouse to allow natural infection by M. larici-populina. The disease 587

resistance and susceptibility levels were scored based on the number of uredinia on the abaxial 588

leaf surface as well as by qRT-PCR (list of genotypes with resistance level is given in 589

Supplemental Table S1). 590

591

Fungal Pathogens and Culture Maintenance 592

Virulent M. larici-populina was collected from a natural population of black poplar 593

located in the floodplain forest of an island in the Oder River near Küstrin-Kietz, Germany. The 594

fungus was multiplied from a single uredium on a susceptible poplar genotype (P. nigra NP1). 595

The infected plants were covered with polyethylene bags in order to collect spores without 596

allowing any condensation of water inside the bags, which might lead to spore germination. The 597

urediniospores were collected from infected poplar leaves using fine brushes and placed in 2 mL 598

micro centrifuge tubes. To dry spores, the tube was inserted in a closed beaker containing dry 599

silica gel for 2-3 days with the cap open. The spores were then stored at -20°C until further use. 600

This spore preservation technique avoided continuous in planta culturing of this obligate 601

biotrophic fungus. Uredospores of M. aecidiodes were collected from a local P. alba tree. 602

603

Inoculation of Poplars with M. larici-populina or M. aecidiodes 604



30

Freshly harvested or frozen urediniospores of M. larici-populina were used for 605

inoculation experiments. Young black poplar trees (approx. 80 cm height and 15-20 leaves) 606

grown in the greenhouse were transferred to a climate chamber (22°C day temperature and 19°C 607

night temperature, 70% relative humidity, 16h/8h light/dark cycle) 7 days before inoculation. For 608

the kinetic infection experiment, 50 individual black poplar trees of approx. equal size were 609

chosen. Each young potted tree was placed in a separate receptacle (18 cm diameter) for 610

watering independently. Half of the plants (N = 25) were inoculated by thoroughly spraying M. 611

larici-populina spore suspension (± 105 spores mL-1) onto the abaxial leaf surfaces. Control 612

plants were sprayed with water (N = 25). Immediately after spraying, each plant was covered 613

with a polyethylene terephthalate bag (Bratschlauch, Toppits; Germany) to maintain high 614

humidity and kept in the dark to facilitate spore germination. After 18 hours, the bags were 615

opened from the top to ensure proper aeration. Five time points were chosen for sampling based 616

on the life-style of the fungus (Hacquard et al., 2011). Samples were taken at 6 hours post 617

inoculation (hpi), and 3, 7, 14, and 21 days post inoculation (dpi). At each time point, 5 618

individual plants were sampled from rust-infected and water-sprayed treatments. Six leaves at 619

the same position (LPI5-10) on each plant were harvested and pooled together to obtain one 620

biological sample and immediately flash frozen under liquid N2. Unless otherwise stated, similar 621

inoculation and sampling techniques were followed for the other rust infection experiments but 622

only one time point (8 dpi) was used for harvesting leaves. Inoculation of hybrid aspen with M. 623

aecidiodes, was carried out in the Glover Greenhouse at the University of Victoria, using a 624

similar set-up. 625

626

In vitro Bioassays with M. larici-populina on Glass Slides 627

Antifungal activities of catechin and PAs against the biotrophic rust fungus were 628

evaluated on glass slides. The germination medium consisted of 1.1% plant agar (Duchefa 629

Biochemie, Haarlem, Netherlands) and 10 mM KCl in water. The medium was sterilized by 630

autoclaving before adding catechin or proanthocyanidins (1.5 mg mL-1). The media were 631

incubated in a water bath at 65°C for an hour to ensure that the phenolic compounds were 632

dissolved completely. Autoclaved medium without compounds was used as a control. 633

Approximately 300 µL liquid medium was pipetted carefully onto a clean glass slide and 634

allowed to solidify. After 5-10 minutes, 20 µL freshly prepared spore suspension (± 104 mL-1) in 635



31

10 mM KCl was pipetted onto the glass slides and spread carefully onto the solidified medium 636

with a plastic inoculation loop. Ten glass slides were prepared for each treatment and each of 637

them was kept in a sterile Petri dish (9 cm diameter) with moist blotting paper to maintain the 638

high humidity required for spore germination. The Petri dishes were incubated in a dark cabinet 639

and the spore germination was monitored every hour under an inverted light microscope 640

(Axiovert 200, Carl Zeiss Microscopy GmbH, Jena, Germany) coupled with a camera 641

(AxioVision). Urediniospore germination rate was determined at 9 hpi and hyphal length was 642

measured at 12 hpi. Three microscopic fields were photographed randomly and considered as 643

technical replicates. The percentage of germinated spores was calculated based on numbers of 644

spore germinated divided by total number of spores observed per microscopic field. Hyphal 645

lengths of the germinated spores in each microscopic field were measured by ImageJ software 646

(https://imagej.nih.gov/ij/index.html). For illustration of the technique, see Supplemental Fig. S8. 647

648

Extraction of Phenolic Compounds from Poplar 649

For extraction of phenolic compounds, poplar tissues (leaf, petiole, stem and root) were 650

ground to fine powder under liquid N2. The stem samples, which contained both bark and wood, 651

were ground with the help of a vibrating mill (Pulverisette 0, Fritsch GmbH, Idar-Oberstein, 652

Germany) while the leaf materials were ground manually using mortar and pestle. The ground 653

samples were lyophilized using an Alpha 1-4 LD Plus freeze dryer (Martin Christ GmbH, 654

Osterode, Germany) at 0.001 mbar pressure and -76°C temperature for 2 days. Approximately 10 655

mg freeze-dried tissue was weighed using an XP26 Microbalance (Mettler-Toledo AG, 656

Greifensee, Switzerland) into 2 mL microcentrifuge tubes. Phenolics were extracted with 1 mL 657

extraction buffer, which contained 10 µg apigenin-7-glucoside (Carl Roth, Karlsruhe, Germany) 658

and 0.4 mg phenyl β-D-glucopyranoside (Sigma-Aldrich St. Louis, MO, USA) as internal 659

standards per mL methanol (analytical grade). One mL extraction buffer was added to each 660

microcentrifuge tube, vortexed vigorously and incubated for 30 min at 20°C, shaking at 2000 661

rpm. The extracts were centrifuged at 13,000 rpm at 4°C for 5 min, and approximately 900 µL 662

supernatant was transferred to a new micro centrifuge tube. Salicinoids were directly analyzed 663

with HPLC-DAD. Samples were diluted 20-fold before analyzing flavan-3-ols by HPLC coupled 664

to a tandem mass spectrometer (LC-MS/MS). 665

666



32

For extraction of oligomeric or polymeric proanthocyanidins, approx. 50 mg freeze dried 667

plant tissue was extracted with analytical grade methanol following the above extraction protocol 668

but additionally the insoluble material was re-extracted with 1 mL 70% acetone. Both 669

supernatants were combined and dried under a stream of nitrogen. The dried samples were re-670

dissolved in 1 mL solvent (1:1, methanol: acetonitrile) and were analyzed by HPLC coupled to a 671

fluorescence detector. Cell wall-bound PAs were measured from the residue remaining after 672

extraction of soluble catechin and PAs using the acid butanol method (Porter et al. 1986) which 673

was modified by Boeckler et al. (2013). Amounts of cell wall-bound PAs were determined using 674

a procyanidin-B1 calibration curve (Extrasynthese, Genay, France). 675

Identification of Phenolics by Liquid Chromatography-Mass Spectrometry with 676

Electrospray Ionization (LC-ESI-MS) 677

The phenolic compounds identified from poplar leaf extracts as well as from LAR and 678

ANR enzyme assays were separated on a reversed phase Nucleodur Sphinx RP18ec column with 679

dimensions of 250 × 4.6 mm and a particle size of 5 µm (Macherey Nagel, Düren, Germany) 680

using an Agilent 1100 series HPLC (Agilent Technologies, Santa Clara, California, USA) with a 681

solvent system of 0.2 % aqueous formic acid (A) and acetonitrile (B) at a flow rate of 1.0 mL 682

min-1. The column temperature was maintained at 25°C. The proportion of B was increased from 683

14-58 % in a linear gradient of 22 min. After the column was washed for 3 min with 100 % B, it 684

was re-equilibrated to the initial eluent composition for 5 min prior to the next analysis. Flow 685

coming from the column was diverted in a ratio of 4:1 before entering the mass spectrometer 686

electrospray chamber. Compound detection and quantification was accomplished with an 687

Esquire 6000 ESI ion trap mass spectrometer (Bruker Daltronics, Leipzig, Germany). Phenolic 688

compounds were analyzed in negative mode scanning a mass-to-charge ratio (m/z) between 100 689

and 1600 with a skimmer voltage of 60 V, a capillary exit voltage of -121 V, and a capillary 690

voltage of 4,000 V. Nitrogen was used as drying gas (11 mL L-1, 330°C) and nebulizer gas 691

pressure was 35 psi. Compounds were identified by mass spectra and by direct comparison with 692

commercial standards as described previously (Boeckler et al., 2013; Hammerbacher et al., 693

2014). Brucker Daltronics Quant Analysis software version 3.4 was used for data processing and 694

compound quantification using a standard smoothing width of 3 and Peak Detection Algorithm 695

version 2. 696

697



33

Quantification of Flavan-3-ol Monomers and Dimers by Liquid Chromatography-Tandem 698

Mass Spectrometry (LC-ESI-MS2) 699

Chromatography was performed on an Agilent 1200 HPLC system. An API 3200 tandem 700

mass spectrometer (Applied Biosystems) equipped with a turbospray ion source was operated in 701

negative ionization mode. Separation was achieved on a Zorbax Eclipse XDB-C18 column (50 × 702

4.6 mm, 1.8 mm, Agilent). Formic acid (0.05%) in water and acetonitrile were employed as 703

mobile phases A and B, respectively. The elution profile was: 0-1 min 100% A; 1-7 min, 0-65% 704

B; 7-8 min, 65-100% B; 8-9 min, 100% B; and 9-10 min, 100% A. The total mobile phase flow 705

rate was 1.1 mL min-1. The column temperature was maintained at 25°C. The instrument 706

parameters were optimized by infusion experiments with pure standards as described by 707

Hammerbacher et al. (2014). The ion spray voltage was maintained at -4,500 V. The turbo gas 708

temperature was set at 700°C. Nebulizing gas was set at 70 psi, curtain gas at 25 psi, heating gas 709

at 60 psi, and collision gas at 10 psi. Multiple reaction monitoring was used to monitor analyte 710

parent ion → product ion: m/z 288.9 →109.1 (collision energy [CE], -34 V; declustering 711

potential [DP], -30 V) for catechin; m/z 289.0 →109.0 (CE, -34 V; DP, -30 V) for epicatechin; 712

m/z 304.8 →125 (CE, -28 V; DP, -30 V) for gallocatechin; m/z 576.9 →289.1 (CE, -30 V; DP, -713

50 V) for PA B1; m/z 430.8 → 268.0 (CE, -46 V; DP, -80 V) for apigenin 7-glucoside. Both Q1 714

and Q3 quadrupoles were maintained at unit resolution. Data acquisition and processing were 715

performed using Analyst 1.5 software (Applied Biosystems). Linearity in ionization efficiencies 716

were verified by analyzing dilution series of a standard. Flavan-3-ol concentrations were 717

determined relative to the calibration curve for apigenin 7-glucoside as an external standard. 718

719

Quantification of PAs by HPLC-FLD 720

PAs were separated on a LiChrosphere diol column with dimensions of 250 × 4 mm and 721

a particle size of 5 µm (Merck Chemicals GmbH, Darmstadt, Germany) using an Agilent 1100 722

series HPLC employing a modified method previously described by Kelm et al. (2006) and 723

Hammerbacher et al. (2014). Briefly, the total mobile phase flow rate for chromatographic 724

separation was 1.2 mL min-1. The column temperature was maintained at 30°C. Compounds 725

were separated using acetonitrile : acetic acid (98:2) and methanol : water : acetic acid (95:3:2) 726

as mobile phases A and B, respectively, with the following elution profile: 0 to 35 min, 0% to 727

40% B in A; 35 to 40 min, 40% B; 40 to 45 min, 40% to 0% B; and 45.1 to 50 min, 0% B. Eluent 728



34

was monitored by FLD with excitation at 276 nm and emission at 316 nm. PA oligomer and 729

polymer concentrations were determined relative to the calibration curve for catechin. 730

731

Quantification of Other Flavonoids and Salicinoids by HPLC-DAD 732

To quantify flavonoids other than flavan-3-ols and salicinoids, an Agilent 1100 Series HPLC 733

System with diode array detector, DAD (Agilent Technologies) were used. The compounds were 734

separated by a Nucleodur Sphinx RP column with dimensions of 250 × 4.6 mm and a particle 735

size 5 μm (Macherey-Nagel). The solvent system for the mobile phase was Milli-Q water 736

(Millipore) and acetonitrile, but otherwise the chromatographic conditions were the same as 737

described above for LC-ESI-MS of poplar phenolics. Data were exported by the software Data 738

Trans at different wavelengths for respective phenolics as previously described by Boeckler et al. 739

(2013). For absolute quantification, analyte peak areas was divided by the peak area of the 740

internal standard phenyl β-D-glucopyranoside and multiplied by the corresponding response 741

factors. 742

743

Reductive Cleavage of PAs 744

Reductive cleavage of PAs was carried out as previously described by Hammerbacher et 745

al. (2014). Briefly, the same samples that were used for PA analysis were diluted 50-fold with 746

methanol. The reaction was performed in HPLC glass vials containing 780 µL diluted extract, 20 747

µL trifluoroacetic acid and 100 µL sodium cyanoborohydrate (0.5 g mL-1 methanol). Reaction 748

mixtures were heated to 65°C for 15 min before adding additional 20 µL trifluoroacetic acid. 749

Vials were sealed tightly and incubated overnight at 65°C. Next morning, the reaction was dried 750

completely under a stream of nitrogen, re-suspended in 800 µL methanol and centrifuged for 5 751

min at 11,000 rpm at 4°C and 780 µL supernatant was transferred to a new vial. The samples 752

were analyzed by LC-ESI-MS2, as described for flavan-3-ol monomers and dimers. 753

754

RNA Isolation and cDNA Synthesis 755

Total RNA from leaf and stem tissue was extracted using the Invitrap Spin Plant RNA 756

Mini Kit (Stratec Biomedical, Birkenfeld, Germany) following the protocols of the manufacturer, 757

except that an additional DNase treatment was included (RNase-Free DNase Set, Qiagen). The 758

first washing step was conducted with 300 µL wash buffer R1. After that, DNase (30 Kunitz 759



35

units in 80 µL volume; RNase-Free water 10 µL and buffer RDD 70 µL) was added onto the 760

column and incubated at room temperature for 15 min. The column was washed with an 761

additional 300 µL wash buffer R1 before continuing with the manufacturer’s protocol. The 762

quantity and quality of the RNA was checked by spectrophotometry (Thermo Scientific™ 763

NanoDrop 2000). Reverse transcription of 1 µg RNA into cDNA was achieved by using 764

SuperScript II reverse transcriptase (Invitrogen) and 50 pmol Oligo(dT)12-18 Primer 765

(Invitrogen) in a reaction volume of 20 µL. The cDNA was diluted 5-fold with sterile water and 766

quality was checked by semi-quantitative reverse transcription polymerase chain reaction (RT-767

PCR) using PtUBQ primer pairs (primer sequences are given in Supplemental Table S2). 768

Identification, Cloning and Sequencing of PnLAR and PnANR Genes from Black Poplar 769

The genome of P. trichocarpa (Tuskan et al., 2006) was utilized to find candidate LAR 770

and ANR genes for P. nigra L. as these two species are closely related. The LAR and ANR 771

protein sequences from apple, grape and tea were used to identify LAR and ANR candidates 772

using blastp searches in the National Center for Biotechnology Information (NCBI) and 773

Phytozome v11 databases. The coding sequences were obtained from Phytozome v11 and 774

complete open reading frames (ORF) were identified using the SeqBuilder software of 775

DNASTAR Lasergene 12 package (DNASTAR, Madison-WI, USA). Consistent with Tsai et al. 776

(2006), three PtLAR and two PtANR genes were identified in the P. trichocarpa genome. 777

Gateway® (Invitrogen)-compatible primers were designed for candidate sequences by using the 778

5’ and 3’ ends of putative LAR and ANR genes from P. trichocarpa (Primer sequences are 779

provided in Supplemental Table S2). Genes encoding LAR and ANR were PCR amplified with 780

Gateway-compatible primers from the cDNA of black poplar using Phusion High-Fidelity DNA 781

Polymerase (New England Biolabs, Thermo Fisher Scientific). The PCR products were purified 782

with the QIAquick PCR purification kit (QIAGEN). Gateway entry clones were made by using 783

BP Clonase II and pDONR207 (Invitrogen) following the manufacturer’s protocol. The 784

pDONR207 constructs harboring PnLAR and PnANR genes were sequenced using 10 pmol of 785

pDON primers (primer sequences are provided in Supplemental Table S2) and the BigDye 786

Terminator v 3.1 Cycle Sequencing Kit (Thermo Fisher Scientific) on an ABI Prism R 3100 787

sequencing system (Applied Biosystems). Sequences from each construct were assembled and 788

translated into protein sequence using DNASTAR Lasergene 12 software. 789

790



36

Heterologous Expression of PnLAR and PnANR Genes in Escherichia coli 791

Three putative PnLAR and two PnANR entry clones were sub-cloned with LR Clonase II 792

(Invitrogen) according to the manufacturer’s instructions into the Gateway- compatible 793

expression vector pDEST15 (Invitrogen), which contains a glutathione S-transferase Tag on the 794

N-terminus of the expressed protein. All constructs were verified by sequencing with gene 795

specific primers. A dihydroflavonol reductase gene (MdDFR) from apple (Malus domestica), 796

which transforms dihydroflavonols to leucoanthocyanidins (Fischer et al., 2003), was also cloned 797

using the above protocols into the Gateway-compatible expression vector pH9GW, a modified 798

pET28a(+) vector (Novagen), which carries a sequence encoding a 9-histidine tag at the N-799

terminus of the expressed protein (O’Maille et al., 2004). For PnLAR expression, chemically 800

competent E. coli, BL21 [DE3] (Invitrogen), were co-transformed with the PnLAR and MdDFR 801

expression constructs. For protein expression, single colonies were inoculated into 5 mL Luria-802

Bertani (LB) broth with 100 µg mL–1 ampicillin and 50 µg mL–1 kanamycin for positive 803

selection, and grown overnight at 37°C. For PnANR expression, BL21 cells were transformed 804

with PnANR expression clones with 100 µg mL–1 ampicillin for positive selection, and grown 805

overnight at 30°C. The 5 mL starter cultures were used to inoculate 50 mL overnight expression 806

medium supplemented with their respective antibiotics and grown at 18°C with continuous 807

shaking (220 rpm) for 2 days. The bacterial cells were harvested by centrifugation. The crude 808

proteins were extracted according to Hammerbacher et al., (2014) and used for enzyme assays or 809

stored at -20°C. 810

811

In vitro Enzyme Assays for Functional Characterization of LARs and ANRs 812

Since the substrates leucocyanidin and cyanidin were not available for LAR and ANR 813

assays, respectively, enzyme assays were conducted using two-step reactions. For LAR 814

characterization, taxifolin was used as a substrate with the co-expressed (PnLAR + MdDFR) 815

crude protein extract. The reactions were performed in a 100 µL reaction volume containing 70 816

µL crude protein extract, 10 µL NADPH (20 mM) and 20 µL taxifolin (50 mM) for 40 min at 817

room temperature. The reactions were stopped by adding 100 µL methanol. The mixtures were 818

centrifuged at 11,000 rpm for 4 min and supernatant was analyzed by an LC-ESI-Ion-trap mass 819

spectrometer. For ANR characterization, an anthocyanin synthase gene (ANS) from Petunia was 820

cloned into pDEST 15, heterologously expressed in E. coli, and crude protein was extracted 821



37

using the protocols described above. The enzyme assay was performed with 200 µL crude 822

protein extracts (100 µL each of the ANR and ANS) and 10 µL catechin (10 mM) as substrate. 823

The reaction mixture also contained 20 µL NADPH (20 mM), 10 µL oxoglutarate (10 mM), 1 824

µL enzyme bovine catalase (40 units mL-1) (Sigma Aldrich, Louis, MO, USA), 40 µL potassium-825

phosphate buffer (0.2 M, pH 6.0), 10 µL ascorbate (50 mM) and 1 µL FeSO4 (1 mM). The 826

reaction mixture was incubated at 28°C overnight. The reaction was stopped by adding another 827

100 µL methanol; centrifuged for 4 min at 11,000 rpm and the supernatant was analyzed by the 828

LC-ESI-Ion-trap mass spectrometer. 829

830

Quantitative Real Time (qRT) PCR 831

To quantify expression of target genes, a segment of ~150 base pairs were amplified 832

using gene specific primers. All primers were designed using Primer3 web version 4.0.0 833

(http://bioinfo.ut.ee/primer3/). The efficiency of each primer pair was tested before qPCR. 834

Primers with efficiencies below 95% were discarded. The reactions were performed in a 20 µL 835

volume containing 10 µL Brilliant III Ultra-Fast SYBR Green QPCR Master Mix (Agilent 836

Technologies), 10 pmol forward and 10 pmol reverse primer, and 2 µL diluted cDNA (approx. 837

100 ng). The qRT-PCR was performed using a CFX Connect Real-Time PCR Detection System 838

(BIO-RAD) using a two-step amplification protocol (cycling parameters: 3 min at 95°C followed 839

by 40 cycles of 10s at 95°C, 30s at 55°C). A non-template water sample was used as reaction 840

control. Transcript abundance was normalized to the abundance of the PtUBQ (Irmisch et al., 841

2013) and was calculated from five biological replicates, with each biological sample being 842

analyzed from three technical replicates. Primer sequences for all genes used in this study are 843

given in Supplemental Table S2. 844

845

Histochemical Staining and Microscopy 846

Fresh plant specimens were embedded into Tissue Freezing Medium (Jung, Leica 847

Biosystems, Wetzlar, Germany) and left for 1 hour at -20°C. Sections (10-20 µm) were made 848

using a CM1850 cryotome (Leica Biosystems, Wetzlar, Germany). Then 2-3 sections were 849

transferred to a clean glass slide and stained for 10 min with approximately 50 µL freshly 850

prepared 1% DMACA solution [1% DMACA (v/v) in absolute ethanol containing 5N HCl (1:1, 851

v/v)]. After 10 min staining, the excess DMACA solution was wiped off carefully, and one drop 852



38

70% glycerol (v/v) was added to the sections. A clean coverslip was put carefully on the 853

sections, and observed under an inverted light microscope (Axiovert 200, Carl Zeiss Microscopy 854

GmbH, Germany) and photographs were taken with a camera (AxioVision). 855

856

Phylogenetic Analysis 857

Full-length amino acid sequences of LARs and ANRs were retrieved from public 858

databases (GenBank/NCBI/EMBL and Phytozome v11). A poplar DFR protein sequence 859

(ortholog of apple DFR) was included. Protein sequences were aligned using a multiple sequence 860

alignment program MAFFT version 7 (Katoh and Standley, 2013) by employing the highly 861

accurate method L-INS-I (sequence alignment is provided in Supplemental Fig. S14). The 862

aligned sequences were then verified and edited using Mesquite 3.04 863

(http://mesquiteproject.org). The maximum likelihood tree was constructed using the software 864

package PhyML-3.0 (Guindon et al., 2010). The amino acid substitution model was LG (Le and 865

Gascuel, 2008). BIONJ distance-based tree was the starting tree by default and then improved by 866

tree topology search by combining NNI (Nearest Neighbor Interchange) and SPR (Subtree 867

Pruning and Regrafting). Bootstrapping was estimated with 1,000 replicates. The tree was 868

viewed using Figtree (http://tree.bio.ed.ac.uk/software/figtree/) and rooted at the midpoint. The 869

tree readability was improved using Adobe Illustrator CS5. Accessions of all peptide sequences 870

are given at the end of the method section. 871

872

Vector Construction and Plant Transformation 873

The binary vector was constructed following the method described by Levée et al. (2009). The 874

transformation of the P. nigra NP1 by an RNAi construct was achieved following a protocol 875

optimized for Populus canescens (Meilan and Ma 2006). To target PnMYB134 mRNA, a 876

fragment between position 512 and 696 of the coding sequence was selected. Transgenic RNAi 877

poplar plants were amplified by micropropagation as described by Behnke et al. (2007). To 878

verify the level of transgenicity, qRT-PCR analysis was done on wild-type, vector control 879

(pCambia), and RNAi plants (lines 2 and 9). Primers for RNAi and qRT are given in the 880

Supplemental Table S2. MYB134 overexpressing lines of hybrid aspen (P. tremula X alba 717-881

1-B4) were available in the Constabel laboratory, propagated on Woody Plant Medium, and 882

acclimated in a mist chamber before being moved to the greenhouse. 883



39

884

Statistical Analysis 885

All data were analyzed by using the statistical package R (version: R 3.4.0). Before analysis, 886

normality and homogeneity of variances were verified using Shapiro-Wilk and Levene’s tests, 887

respectively. Whenever necessary, data were square root or log transformed to meet the 888

assumptions for parametric testing. Data were analyzed either by one-way or two-way ANOVA, 889

depending on the overall number of factors in each experiment. Tukey’s post-hoc test was 890

performed to compare differences among different groups. 891

892

Accession Numbers 893

Sequences used in this article can be found in the GenBank/EMBL/Phytozome libraries 894

under the following accession numbers: MdLAR1 (DQ139836, Malus domestica), MdLAR2 895

(DQ139837, Malus domestica), PcLAR1 (DQ251190, Pyrus communis), PcLAR2 (DQ251191, 896

Pyrus communis), FxaLAR1 (DQ834906, Fragaria x ananassa), VvLAR1 (BN000698, Vitis 897

vinifera), VvLAR2 (3I6IA, Vitis vinifera), CsLAR (GU992401, Camellia sinensis), MtLAR 898

(CAI56327.1, Medicago truncatula) LcLAR1 (DQ49103, Lotus corniculatus), LcLAR2 899

(DQ49105, Lotus corniculatus), PaLAR1 (KC589001, Picea abies), PaLAR2 (KC589002, Picea 900

abies), PaLAR3 (KC589003, Picea abies), TcLAR (ADD51358, Theobroma cacao), GbANR 901

(AAU95082, Ginkgo biloba), LcANR (ABC71337, Lotus corniculatus), TcANR (ADD51354, 902

Theobroma cacao), FxaANR (ABG76842, Fragaria x ananassa), MtANR (AAN77735.1, 903

Medicago truncatula), MdANR (AAZ79363, Malus domestica), CsANR1 (GU992402, Camellia 904

sinensis), CsANR2 (GU992400, Camellia sinensis), PnLAR1 (KY751539, Populus nigra), 905

PnLAR2 (KY751540, Populus nigra), PnLAR3 (KY751541, Populus nigra), PnANR1 906

(KY751542, Populus nigra), PnANR2 (KY751543, Populus nigra), PtDFR1 907

(Potri.005G229500, Populus trichocarpa). 908

909

SUPPLEMENTAL DATA 910

Supplemental Figure S1. Changes in Poplar Flavonoids and Salicinoids during Rust Infection. 911

Supplemental Figure S2. Constitutive Levels of Flavan-3-ols and Proanthocyanidins in 912

Different Tissues of 6 Month-Old Black Poplar Saplings (P. nigra NP1). 913



40

Supplemental Figure S3. Transcript Abundances of LAR and ANR Genes Catalyzing the Last 914

Steps of Flavan-3-ol Biosynthesis in Black Poplar Saplings (P. nigra NP1). 915

Supplemental Figure S4. Constitutive Levels of Salicinoids in Different Tissues of Black 916

Poplar. 917

Supplemental Figure S5. Degree of PA Polymerization in Poplar Leaves and Stems after 918

Fungal Infections. 919

Supplemental Figure S6. Changes in Flavan-3-ol Monomers Epicatechin and Gallocatechin in 920

Leaves of Different Poplar Genotypes after 8 days Infection with Rust Fungus. 921

Supplemental Figure S7. Composition of Flavan-3-ol Monomers after Hydrolysis of PAs in Different 922

Poplar Genotypes with or without Rust Infection. 923

Supplemental Figure S8. Relative Abundance of LAR and ANR mRNA Transcripts in Water-924

Treated Control and Rust Infected Leaves of Poplar Genotypes 8 Days Post Inoculation. 925

Supplemental Figure S9. Illustration of in vitro Bioassay with Biotrophic Rust Fungus (M. 926

larici-populina) on Glass Slides. 927

Supplemental Figure S10. Effect of Different Phenolic Secondary Metabolites on M. larici-928

populina Spore Germination in vitro. 929

Supplemental Figure S11. Silencing PnMYB134 Regulating Flavan-3-ols and PA Biosynthesis 930

in Black Poplar Partially Influenced other Phenolic Metabolites. 931

Supplemental Figure S12. Specificity of Dimethylaminocinnamaldehyde (DMACA) Staining 932

for Different Poplar Phenolic Metabolites. 933

Supplemental Figure S13. Alignment of the Protein Sequences. 934

Supplement Table S1. Preliminary Screening of Poplar Genotypes for Resistance against Rust 935

Fungus M. larici-populina under Natural Conditions. 936

Supplement Table S2. List of Primers Used in this Study. 937

938 939

ACKNOWLEDGMENTS 940

We thank Dr. Michael Reichelt for his help with chemical analyses and Bettina 941

Raguschke for her assistance in the laboratory, Charlotte Lauder for work during her internship, 942

all members of the greenhouse team, especially Andreas Weber, for growing hundreds of poplar 943

plants used for this study, Richard Hamelin and Nicolas Feau for the M. aecidoides spores, Jake 944

Ketterer for help with plant care, the Northwest German Forest Research Station 945



41

(Nordwestdeutsche Forstliche Versuchsanstalt) for providing stem cuttings of different poplar 946

genotypes, and anonymous reviewers for their valuable comments and suggestions. 947

948

949

950

951

952

953

954

955

FIGURE LEGENDS 956

Figure 1. Catechin and Proanthocyanidins Accumulate in Rust-Infected Black Poplar 957

Leaves as Antimicrobial Defenses. (A) Experimental design for controlled inoculation with rust 958

fungus using 50 young black poplar trees (left). At each time point, five plants from each 959

treatment were harvested with each replicate consisting of the same six leaves from a single plant 960

as depicted (right). (B) Catechin (2,3-trans-(+)-flavan-3-ol monomer) and (C) PA dimers were 961

measured by LC-MS/MS. (D) PA oligomers with up to 8 monomeric units measured by HPLC-962

FLD. (E) Cell wall-bound PAs were measured from the residue remaining after extraction of 963

soluble catechin and PAs using the butanol-HCl method. The amounts of PA oligomers and cell 964

wall-bound PAs are expressed as catechin and procyanidin-B1 equivalents respectively. Data 965

were analyzed by two-way ANOVA (factors were: “tr” = treatment, “t” = time post inoculation, 966

and “tr × t” = interaction effect). Corresponding p-values are indicated in the graphs. (F) 967

Composition of flavan-3-ol monomeric units after hydrolytic cleavage of PAs. Metabolite data 968

(catechin and epicatechin) were analyzed separately by two-way ANOVA (tr: p < 0.01, t: p < 969

0.01, tr × t: p < 0.01; for both metabolites). (G) Colonization of rust fungus in poplar leaves at 970

different times after inoculation. The relative growth of the rust fungus was determined with 971

qRT-PCR by normalizing poplar UBQ gene expression to quantify the relative growth of the 972

fungus. Data were analyzed by one-way ANOVA followed by Tukey’s post-hoc test and 973

different letters denote statistically significant differences at 95% confidence. Data presented in 974

all graphs are mean ± SE (N = 5). [h = hour, d = day, ctrl = control, rust = rust-infected, DW = 975

dry weight]. 976



42

977

Figure 2. Heterologous Expression and Biochemical Characterization of Enzymes Involved 978

in the Last Steps of Flavan-3-ol Biosynthesis in Black Poplar. (A) Biosynthetic route to 979

monomeric flavan-3-ols and proanthocyanidins. (B) Catalytic activities of leucoanthocyanidin 980

reductase enzymes (LARs). A construct for each LAR gene was co-expressed with an apple 981

dihydroflavonol reductase (MdDFR) in the BL-21 strain of Escherichia coli. The crude protein 982

extracts were assayed with taxifolin (a dihydroflavonol) as a substrate. The apple DFR converted 983

taxifolin to leucocyanidin which was subsequently converted to catechin by the poplar LAR 984

proteins, as measured by LC-MS. (C) Catalytic activities of anthocyanidin reductase enzymes 985

(ANRs). Each ANR construct was expressed in BL-21 and the crude extract of the expressed 986

protein was used for the enzymatic assay. The crude extract of a Petunia anthocyanidin synthase 987

(ANS) was also added to each assay and catechin was added as substrate (shown with a dashed 988

line arrow). The ANS converted catechin to cyanidin, which was then used as substrate for the 989

poplar ANRs to produce epicatechin. The numbers on top of the chromatograms correspond to 990

the compounds shown in Figure 2A (left). 991

992

Figure 3. Evolutionary Relationship of LAR and ANR Genes of Black Poplar and Other 993

Plant Species. The corresponding protein sequences were aligned with MAFFT using the L-994

INS-I method. The maximum likelihood tree was constructed using PhyML-3.1 employing the 995

amino acid substitution model LG (Le and Gascuel, 2008). Non-parametric bootstrap analysis 996

was performed with 1000 iterations and values next to each node indicate the branch support 997

percentages (values > 70 are included). The scale bar indicates amino acid substitution per site. 998

The tree was rooted to the midpoint. The peptide sequence alignment is provided in 999

supplemental Figure 14. Accession numbers of all sequences including species names are given 1000

at the end of the methods section. 1001

1002

Figure 4. Transcript Accumulation of Flavan-3-ol Biosynthetic Genes and a Transcription 1003

Factor Regulating PA Biosynthesis in P. nigra after Rust Infection. Gene expression of three 1004

PnLARs (A-C) and two PnANRs (D-E) from P. nigra NP1 that were biochemically characterized 1005

in this study measured by qRT-PCR. Gene expression was normalized to PnUBQ. Data were 1006

analyzed by two-way ANOVA (factors were: “tr” = treatment, “t” = time post inoculation, and 1007



43

“tr × t” = interaction effect). Corresponding metabolite data is depicted in Fig 1. Data 1008

represented in graphs are mean ± SE (N = 5), and each biological replicate consisted of three 1009

technical replicates. 1010

1011

Figure 5. Poplar Genotypes Moderately Resistant to Rust Fungus Contain Constitutively 1012

Higher Amounts of Catechin and Proanthocyanidins. (A) Catechin (flavan-3-ol monomer) 1013

and (B) PA dimers were measured by LC-MS/MS. (C) Flavan-3-ol oligomers measured up to 10 1014

monomeric units by HPLC-FLD. (D) Cell wall-bound PAs were measured from the residue 1015

remaining after extraction of soluble catechin and PAs using the butanol-HCl method. The 1016

amounts of PA oligomers and cell wall-bound PAs are expressed as catechin and procyanidin-B1 1017

equivalents respectively. Data (A-B) were analyzed by two-way ANOVA (factors were: “g” = 1018

genotype, “tr” = treatment, and “g × tr” = interaction effect). Corresponding p-values are 1019

indicated in the graphs. (E) Fungal growth in different poplar genotypes 8 days post inoculation. 1020

The growth of the fungus was determined by qRT-PCR. M. larici-populina Actin gene 1021

expression was normalized to poplar UBQ gene expression to quantify the colonization of the 1022

fungus in poplar leaves. (F) Biomass of poplar genotypes in one growing season under natural 1023

environmental conditions. The shoot biomass was determined in autumn (November, 2015) 1024

when all leaves had dropped at the end of the growing season. In the susceptible genotypes, 1025

defoliation was earlier due to severe rust infection. Data in figures E-F were analyzed by one-1026

way ANOVA followed by Tukey’s post-hoc test with different letters indicating statistically 1027

significant differences at 95% confidence. Data represented in the graphs are mean ± SE (N = 5). 1028

1029

Figure 6. Catechin and Proanthocyanidins Show a Direct Inhibitory Effect on Spore 1030

Germination and Hyphal Growth of the Biotrophic Rust Fungus in vitro. (A-B) Germination 1031

of rust urediniospores on glass slide at 9 hpi, (A) Spore germination shown in control medium 1032

(B) Spore germination shown in medium supplemented with catechin. (C-D) Patterns of 1033

mycelial branching at 18 hpi, (C) control medium (D) medium supplemented with catechin (E) 1034

Urediniospore germination percentage determined at 9 hpi (F) Hyphal lengths of germinated 1035

urediniospores at 12 hpi. Data were analyzed by one-way ANOVA followed by Tukey’s post-1036

hoc test, and different letters indicating treatment groups statistically different at 95% 1037



44

confidence. Scale bars indicate 50 µm. Data represented in the graphs are mean ± SE (N = 8), 1038

where each replicate is a mean of three technical replicates. 1039

Figure 7. Overexpression of MYB134 in hybrid aspen (P. tremula × alba) leads to an up-1040

regulation of flavan-3-ol and PA biosynthesis, and reduced rust (M. aecidiodes) 1041

susceptibility. (A-C) Concentrations of catechin, PA dimers and PA oligomers respectively in 1042

aspen leaves. Catechin and PA dimers were measured by LC-MS/MS and PA oligomers were 1043

measured up to 12 monomeric units by HPLC-FLD. (D) Relative expression of MYB134 mRNA 1044

which was normalized to UBQ mRNA levels. (E) Relative colonization of rust fungus M . 1045

aecidiodes in aspen leaves determined by qRT-PCR. The rust Actin mRNA levels were 1046

normalized to poplar UBQ mRNA to quantify rust colonization. Data were analyzed by one-way 1047

ANOVA followed by Tukey’s post-hoc test and different letters indicate groups statistically 1048

different at 95% confidence. Data represented in graphs are mean + SE (N = 5-8). 1049

1050

Figure 8. Down-regulation of flavan-3-ol and PA biosynthesis in black poplar (P. nigra 1051

NP1) by silencing MYB134 transcription factor results in an increased susceptibility to rust 1052

infection (M. larici-populina). (A-B) Concentrations of catechin, PA dimers in poplar leaves 1053

measured by LC-MS/MS (C) PA oligomers were measured up to 8 monomeric units by HPLC-1054

FLD. (D) Relative expression of MYB134 mRNA which was normalized to UBQ mRNA levels. 1055

(E) Relative colonization of rust fungus in poplar leaves determined by qRT-PCR. The rust Actin 1056

mRNA levels were normalized to poplar UBQ mRNA to quantify relative rust colonization. Data 1057

in figures A-D were analyzed by two-way ANOVA (Factors were: “L” = poplar lines, “tr” = 1058

treatment [control and rust], L × tr = interaction effect) followed by Tukey’s post-hoc test, 1059

different letters indicate groups statistically different at 95% confidence. Data in figure E were 1060

analyzed by one-way ANOVA followed by Tukey’s post-hoc test and different letters indicate 1061

lines statistically different at 95% confidence. Data represented in graphs are mean + SE (N = 4-1062

5). 1063

1064

Figure 9. Localization of Flavan-3-ols and PAs in Poplar Leaves with or without Rust 1065

Infection. Sections (20 µm thickness) were made from the first fully expanded mature leaf (LPI-1066

5) and were stained with 4-dimethylaminocinnamaldehyde (DMACA). (A-E) Cross sections 1067

(leaf lamina) of the genotype NP1, Leip, Dorn, Kew and Bla respectively (F) Cross section of 1068



45

NP1 petiole. (G-K) Cross sections (leaf lamina) of NP1, Leip, Dorn, Kew and Bla genotypes 1069

respectively after rust infection (L) Petiole cross section of NP1 infected with rust fungus 5 days 1070

post inoculation. Scale bars 100 µm (K, for all leaf laminae) and 200 µm (F, L). The genotypes 1071

NP1 and Leip were found to be very susceptible to the rust fungus, while the genotypes Dorn, 1072

Kew and Bla were found to be moderately resistant. Triangles indicate fungal penetration and 1073

colonization sites. [ue = upper epidermis, le = lower epidermis, vb = vascular bundles, s = 1074

stomata, sp = spongy parenchyma, pa = palisade parenchyma, e = epidermis, c = cortex]. 1075

1076

1077

1078

1079

1080



Parsed CitationsAbeynayake, S.W., Panter, S., Mouradov, A., and Spangenberg, G. (2011). A high-resolution method for the localization ofproanthocyanidins in plant tissues. Plant Methods 7, 13.

Pubmed: Author and TitleCrossRef: Author and TitleGoogle Scholar: Author Only Title Only Author and Title

Ayres, M.P., Clausen, T.P., MacLean, S.F., Redman, A.M., and Reichardt, P.B. (1997). Diversity of structure and anti-herbivore activity incondensed tannins. Ecology 78, 1696-1712.


Azaiez, A., Boyle, B., Levee, V., and Seguin, A. (2009). Transcriptome profiling in hybrid poplar following interactions with Melampsorarust fungi. Mol Plant Microbe Interact 22, 190-200.


Barbehenn, R.V., and Peter Constabel, C. (2011). Tannins in plant–herbivore interactions. Phytochemistry 72, 1551-1565.Pubmed: Author and TitleCrossRef: Author and TitleGoogle Scholar: Author Only Title Only Author and Title

Barry, K.M., Davies, N.W., and Mohammed, C.L. (2002). Effect of season and different fungi on phenolics in response to xylemwounding and inoculation in Eucalyptus nitens. Forest Pathology 32, 163-178.


Behnke, K., Ehlting, B., Teuber, M., Bauerfeind, M., Louis, S., Hansch, R., Polle, A., Bohlmann, J., and Schnitzler, J.P. (2007).Transgenic, non-isoprene emitting poplars don't like it hot. Plant J 51, 485-499.


Bennett, R.N., and Wallsgrove, R.M. (1994). Secondary metabolites in plant defence mechanisms. New Phytologist 127, 617-633.Pubmed: Author and TitleCrossRef: Author and TitleGoogle Scholar: Author Only Title Only Author and Title

Boeckler, G.A., Gershenzon, J., and Unsicker, S.B. (2011). Phenolic glycosides of the Salicaceae and their role as anti-herbivoredefenses. Phytochemistry 72, 1497-1509.


Boeckler, G.A., Gershenzon, J., and Unsicker, S.B. (2013). Gypsy moth caterpillar feeding has only a marginal impact on phenoliccompounds in old-growth black poplar. J Chem Ecol 39, 1301-1312.


Boeckler, G.A., Towns, M., Unsicker, S.B., Mellway, R.D., Yip, L., Hilke, I., Gershenzon, J., and Constabel, C.P. (2014). Transgenicupregulation of the condensed tannin pathway in poplar leads to a dramatic shift in leaf palatability for two tree-feeding Lepidoptera. JChem Ecol 40, 150-158.


Bogs, J., Downey, M.O., Harvey, J.S., Ashton, A.R., Tanner, G.J., and Robinson, S.P. (2005). Proanthocyanidin synthesis and expressionof genes encoding leucoanthocyanidin reductase and anthocyanidin reductase in developing grape berries and grapevine leaves.Plant Physiol 139, 652-663.


Busby, P.E., Newcombe, G., Dirzo, R., and Whitham, T.G. (2013). Genetic basis of pathogen community structure for foundation treespecies in a common garden and in the wild. Journal of Ecology 101, 867-877.



http://www.ncbi.nlm.nih.gov/pubmed?term=Abeynayake%2C S%2EW%2E%2C Panter%2C S%2E%2C Mouradov%2C A%2E%2C and Spangenberg%2C G%2E %282011%29%2E A high%2Dresolution method for the localization of proanthocyanidins in plant tissues%2E Plant Methods 7%2C 13%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Abeynayake, S.W., Panter, S., Mouradov, A., and Spangenberg, G. (2011). A high-resolution method for the localization of proanthocyanidins in plant tissues. Plant Methods 7, 13.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Abeynayake,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=A high-resolution method for the localization of proanthocyanidins in plant tissues&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=A high-resolution method for the localization of proanthocyanidins in plant tissues&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Abeynayake,&as_ylo=2011&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Ayres%2C M%2EP%2E%2C Clausen%2C T%2EP%2E%2C MacLean%2C S%2EF%2E%2C Redman%2C A%2EM%2E%2C and Reichardt%2C P%2EB%2E %281997%29%2E Diversity of structure and anti%2Dherbivore activity in condensed tannins%2E Ecology 78%2C 1696%2D1712%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Ayres, M.P., Clausen, T.P., MacLean, S.F., Redman, A.M., and Reichardt, P.B. (1997). Diversity of structure and anti-herbivore activity in condensed tannins. Ecology 78, 1696-1712.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Ayres,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Diversity of structure and anti-herbivore activity in condensed tannins&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Diversity of structure and anti-herbivore activity in condensed tannins&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Ayres,&as_ylo=1997&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Azaiez%2C A%2E%2C Boyle%2C B%2E%2C Levee%2C V%2E%2C and Seguin%2C A%2E %282009%29%2E Transcriptome profiling in hybrid poplar following interactions with Melampsora rust fungi%2E Mol Plant Microbe Interact 22%2C 190%2D200%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Azaiez, A., Boyle, B., Levee, V., and Seguin, A. (2009). Transcriptome profiling in hybrid poplar following interactions with Melampsora rust fungi. Mol Plant Microbe Interact 22, 190-200.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Azaiez,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Transcriptome profiling in hybrid poplar following interactions with Melampsora rust fungi&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Transcriptome profiling in hybrid poplar following interactions with Melampsora rust fungi&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Azaiez,&as_ylo=2009&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Barbehenn%2C R%2EV%2E%2C and Peter Constabel%2C C%2E %282011%29%2E Tannins in plant�??herbivore interactions%2E Phytochemistry 72%2C 1551%2D1565%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Barbehenn, R.V., and Peter Constabel, C. (2011). Tannins in plant?herbivore interactions. Phytochemistry 72, 1551-1565.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Barbehenn,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Tannins in plantâ�?�?herbivore interactions&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Tannins in plantâ�?�?herbivore interactions&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Barbehenn,&as_ylo=2011&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Barry%2C K%2EM%2E%2C Davies%2C N%2EW%2E%2C and Mohammed%2C C%2EL%2E %282002%29%2E Effect of season and different fungi on phenolics in response to xylem wounding and inoculation in Eucalyptus nitens%2E Forest Pathology 32%2C 163%2D178%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Barry, K.M., Davies, N.W., and Mohammed, C.L. (2002). Effect of season and different fungi on phenolics in response to xylem wounding and inoculation in Eucalyptus nitens. Forest Pathology 32, 163-178.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Barry,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Effect of season and different fungi on phenolics in response to xylem wounding and inoculation in Eucalyptus nitens&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Effect of season and different fungi on phenolics in response to xylem wounding and inoculation in Eucalyptus nitens&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Barry,&as_ylo=2002&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Behnke%2C K%2E%2C Ehlting%2C B%2E%2C Teuber%2C M%2E%2C Bauerfeind%2C M%2E%2C Louis%2C S%2E%2C Hansch%2C R%2E%2C Polle%2C A%2E%2C Bohlmann%2C J%2E%2C and Schnitzler%2C J%2EP%2E %282007%29%2E Transgenic%2C non%2Disoprene emitting poplars don%27t like it hot%2E Plant J 51%2C 485%2D499%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Behnke, K., Ehlting, B., Teuber, M., Bauerfeind, M., Louis, S., Hansch, R., Polle, A., Bohlmann, J., and Schnitzler, J.P. (2007). Transgenic, non-isoprene emitting poplars don't like it hot. Plant J 51, 485-499.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Behnke,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Transgenic, non-isoprene emitting poplars don't like it hot&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Transgenic, non-isoprene emitting poplars don't like it hot&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Behnke,&as_ylo=2007&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Bennett%2C R%2EN%2E%2C and Wallsgrove%2C R%2EM%2E %281994%29%2E Secondary metabolites in plant defence mechanisms%2E New Phytologist 127%2C 617%2D633%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Bennett, R.N., and Wallsgrove, R.M. (1994). Secondary metabolites in plant defence mechanisms. New Phytologist 127, 617-633.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Bennett,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Secondary metabolites in plant defence mechanisms&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Secondary metabolites in plant defence mechanisms&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Bennett,&as_ylo=1994&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Boeckler%2C G%2EA%2E%2C Gershenzon%2C J%2E%2C and Unsicker%2C S%2EB%2E %282011%29%2E Phenolic glycosides of the Salicaceae and their role as anti%2Dherbivore defenses%2E Phytochemistry 72%2C 1497%2D1509%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Boeckler, G.A., Gershenzon, J., and Unsicker, S.B. (2011). Phenolic glycosides of the Salicaceae and their role as anti-herbivore defenses. Phytochemistry 72, 1497-1509.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Boeckler,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Phenolic glycosides of the Salicaceae and their role as anti-herbivore defenses&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Phenolic glycosides of the Salicaceae and their role as anti-herbivore defenses&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Boeckler,&as_ylo=2011&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Boeckler%2C G%2EA%2E%2C Gershenzon%2C J%2E%2C and Unsicker%2C S%2EB%2E %282013%29%2E Gypsy moth caterpillar feeding has only a marginal impact on phenolic compounds in old%2Dgrowth black poplar%2E J Chem Ecol 39%2C 1301%2D1312%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Boeckler, G.A., Gershenzon, J., and Unsicker, S.B. (2013). Gypsy moth caterpillar feeding has only a marginal impact on phenolic compounds in old-growth black poplar. J Chem Ecol 39, 1301-1312.


http://scholar.google.com/scholar?as_q=Gypsy moth caterpillar feeding has only a marginal impact on phenolic compounds in old-growth black poplar&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Gypsy moth caterpillar feeding has only a marginal impact on phenolic compounds in old-growth black poplar&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Boeckler,&as_ylo=2013&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Boeckler%2C G%2EA%2E%2C Towns%2C M%2E%2C Unsicker%2C S%2EB%2E%2C Mellway%2C R%2ED%2E%2C Yip%2C L%2E%2C Hilke%2C I%2E%2C Gershenzon%2C J%2E%2C and Constabel%2C C%2EP%2E %282014%29%2E Transgenic upregulation of the condensed tannin pathway in poplar leads to a dramatic shift in leaf palatability for two tree%2Dfeeding Lepidoptera%2E J Chem Ecol 40%2C 150%2D158%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Boeckler, G.A., Towns, M., Unsicker, S.B., Mellway, R.D., Yip, L., Hilke, I., Gershenzon, J., and Constabel, C.P. (2014). Transgenic upregulation of the condensed tannin pathway in poplar leads to a dramatic shift in leaf palatability for two tree-feeding Lepidoptera. J Chem Ecol 40, 150-158.


http://scholar.google.com/scholar?as_q=Transgenic upregulation of the condensed tannin pathway in poplar leads to a dramatic shift in leaf palatability for two tree-feeding Lepidoptera&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Transgenic upregulation of the condensed tannin pathway in poplar leads to a dramatic shift in leaf palatability for two tree-feeding Lepidoptera&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Boeckler,&as_ylo=2014&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Bogs%2C J%2E%2C Downey%2C M%2EO%2E%2C Harvey%2C J%2ES%2E%2C Ashton%2C A%2ER%2E%2C Tanner%2C G%2EJ%2E%2C and Robinson%2C S%2EP%2E %282005%29%2E Proanthocyanidin synthesis and expression of genes encoding leucoanthocyanidin reductase and anthocyanidin reductase in developing grape berries and grapevine leaves%2E Plant Physiol 139%2C 652%2D663%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Bogs, J., Downey, M.O., Harvey, J.S., Ashton, A.R., Tanner, G.J., and Robinson, S.P. (2005). Proanthocyanidin synthesis and expression of genes encoding leucoanthocyanidin reductase and anthocyanidin reductase in developing grape berries and grapevine leaves. Plant Physiol 139, 652-663.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Bogs,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Proanthocyanidin synthesis and expression of genes encoding leucoanthocyanidin reductase and anthocyanidin reductase in developing grape berries and grapevine leaves&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Proanthocyanidin synthesis and expression of genes encoding leucoanthocyanidin reductase and anthocyanidin reductase in developing grape berries and grapevine leaves&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Bogs,&as_ylo=2005&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Busby%2C P%2EE%2E%2C Newcombe%2C G%2E%2C Dirzo%2C R%2E%2C and Whitham%2C T%2EG%2E %282013%29%2E Genetic basis of pathogen community structure for foundation tree species in a common garden and in the wild%2E Journal of Ecology 101%2C 867%2D877%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Busby, P.E., Newcombe, G., Dirzo, R., and Whitham, T.G. (2013). Genetic basis of pathogen community structure for foundation tree species in a common garden and in the wild. Journal of Ecology 101, 867-877.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Busby,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Genetic basis of pathogen community structure for foundation tree species in a common garden and in the wild&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Genetic basis of pathogen community structure for foundation tree species in a common garden and in the wild&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Busby,&as_ylo=2013&as_allsubj=all&hl=en&c2coff=1


Chen, Z., Liang, J., Zhang, C., and Rodrigues, C.J., Jr. (2006). Epicatechin and catechin may prevent coffee berry disease by inhibitionof appressorial melanization of Colletotrichum kahawae. Biotechnol Lett 28, 1637-1640.


Clavijo McCormick, A., Irmisch, S., Reinecke, A., Boeckler, G.A., Veit, D., Reichelt, M., Hansson, B.S., Gershenzon, J., Kollner, T.G., andUnsicker, S.B. (2014). Herbivore-induced volatile emission in black poplar: regulation and role in attracting herbivore enemies. PlantCell Environ 37, 1909-1923.


Danielsson, M., Lunden, K., Elfstrand, M., Hu, J., Zhao, T., Arnerup, J., Ihrmark, K., Swedjemark, G., Borg-Karlson, A.K., and Stenlid, J.(2011). Chemical and transcriptional responses of Norway spruce genotypes with different susceptibility to Heterobasidion spp.infection. BMC Plant Biol 11, 154.


de Colmenares, N.G., Ramírez-Martínez, J.R., Aldana, J.O., Ramos-Niño, M.E., Clifford, M.N., Pékerar, S., and Méndez, B. (1998).Isolation, characterisation and determination of biological activity of coffee proanthocyanidins. Journal of the Science of Food andAgriculture 77, 368-372.


Debeaujon, I., Nesi, N., Perez, P., Devic, M., Grandjean, O., Caboche, M., and Lepiniec, L. (2003). Proanthocyanidin-accumulating cellsin Arabidopsis testa: regulation of differentiation and role in seed development. Plant Cell 15, 2514-2531.


Dixon, R.A., Xie, D.-Y., and Sharma, S.B. (2005). Proanthocyanidins – a final frontier in flavonoid research? New Phytologist 165, 9-28.Pubmed: Author and TitleCrossRef: Author and TitleGoogle Scholar: Author Only Title Only Author and Title

Dixon, R.A., Liu, C., and Jun, J.H. (2013). Metabolic engineering of anthocyanins and condensed tannins in plants. Current Opinion inBiotechnology 24, 329-335.


Duplessis, S., Major, I., Martin, F., and Séguin, A. (2009). Poplar and Pathogen Interactions: Insights from Populus Genome-WideAnalyses of Resistance and Defense Gene Families and Gene Expression Profiling. Critical Reviews in Plant Sciences 28, 309-334.


Duplessis, S., Cuomo, C.A., Lin, Y.C., Aerts, A., Tisserant, E., et al. (2011). Obligate biotrophy features unraveled by the genomicanalysis of rust fungi. Proc Natl Acad Sci U S A 108, 9166-9171.


Ferreira, D., and Slade, D. (2002). Oligomeric proanthocyanidins: naturally occurring O-heterocycles. Nat Prod Rep 19, 517-541.Pubmed: Author and TitleCrossRef: Author and TitleGoogle Scholar: Author Only Title Only Author and Title

Fischer, T.C., Halbwirth, H., Meisel, B., Stich, K., and Forkmann, G. (2003). Molecular cloning, substrate specificity of the functionallyexpressed dihydroflavonol 4-reductases from Malus domestica and Pyrus communis cultivars and the consequences for flavonoidmetabolism. Arch Biochem Biophys 412, 223-230.


Guindon, S., Dufayard, J.F., Lefort, V., Anisimova, M., Hordijk, W., and Gascuel, O. (2010). New algorithms and methods to estimatemaximum-likelihood phylogenies: assessing the performance of PhyML 3.0. Syst Biol 59, 307-321.


Hacquard, S., Petre, B., Frey, P., Hecker, A., Rouhier, N., and Duplessis, S. (2011). The poplar-poplar rust interaction: insights from www.plantphysiol.orgon March 18, 2020 - Published by Downloaded from

Copyright © 2017 American Society of Plant Biologists. All rights reserved.

http://www.ncbi.nlm.nih.gov/pubmed?term=Chen%2C Z%2E%2C Liang%2C J%2E%2C Zhang%2C C%2E%2C and Rodrigues%2C C%2EJ%2E%2C Jr%2E %282006%29%2E Epicatechin and catechin may prevent coffee berry disease by inhibition of appressorial melanization of Colletotrichum kahawae%2E Biotechnol Lett 28%2C 1637%2D1640%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Chen, Z., Liang, J., Zhang, C., and Rodrigues, C.J., Jr. (2006). Epicatechin and catechin may prevent coffee berry disease by inhibition of appressorial melanization of Colletotrichum kahawae. Biotechnol Lett 28, 1637-1640.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Chen,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Epicatechin and catechin may prevent coffee berry disease by inhibition of appressorial melanization of Colletotrichum kahawae&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Epicatechin and catechin may prevent coffee berry disease by inhibition of appressorial melanization of Colletotrichum kahawae&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Chen,&as_ylo=2006&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Clavijo McCormick%2C A%2E%2C Irmisch%2C S%2E%2C Reinecke%2C A%2E%2C Boeckler%2C G%2EA%2E%2C Veit%2C D%2E%2C Reichelt%2C M%2E%2C Hansson%2C B%2ES%2E%2C Gershenzon%2C J%2E%2C Kollner%2C T%2EG%2E%2C and Unsicker%2C S%2EB%2E %282014%29%2E Herbivore%2Dinduced volatile emission in black poplar%3A regulation and role in attracting herbivore enemies%2E Plant Cell Environ 37%2C 1909%2D1923%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Clavijo McCormick, A., Irmisch, S., Reinecke, A., Boeckler, G.A., Veit, D., Reichelt, M., Hansson, B.S., Gershenzon, J., Kollner, T.G., and Unsicker, S.B. (2014). Herbivore-induced volatile emission in black poplar: regulation and role in attracting herbivore enemies. Plant Cell Environ 37, 1909-1923.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Clavijo&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Herbivore-induced volatile emission in black poplar: regulation and role in attracting herbivore enemies&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Herbivore-induced volatile emission in black poplar: regulation and role in attracting herbivore enemies&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Clavijo&as_ylo=2014&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Danielsson%2C M%2E%2C Lunden%2C K%2E%2C Elfstrand%2C M%2E%2C Hu%2C J%2E%2C Zhao%2C T%2E%2C Arnerup%2C J%2E%2C Ihrmark%2C K%2E%2C Swedjemark%2C G%2E%2C Borg%2DKarlson%2C A%2EK%2E%2C and Stenlid%2C J%2E %282011%29%2E Chemical and transcriptional responses of Norway spruce genotypes with different susceptibility to Heterobasidion spp%2E infection%2E BMC Plant Biol 11%2C 154%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Danielsson, M., Lunden, K., Elfstrand, M., Hu, J., Zhao, T., Arnerup, J., Ihrmark, K., Swedjemark, G., Borg-Karlson, A.K., and Stenlid, J. (2011). Chemical and transcriptional responses of Norway spruce genotypes with different susceptibility to Heterobasidion spp. infection. BMC Plant Biol 11, 154.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Danielsson,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Chemical and transcriptional responses of Norway spruce genotypes with different susceptibility to Heterobasidion spp&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Chemical and transcriptional responses of Norway spruce genotypes with different susceptibility to Heterobasidion spp&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Danielsson,&as_ylo=2011&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=de Colmenares%2C N%2EG%2E%2C Ram�rez%2DMart�nez%2C J%2ER%2E%2C Aldana%2C J%2EO%2E%2C Ramos%2DNi�o%2C M%2EE%2E%2C Clifford%2C M%2EN%2E%2C P�kerar%2C S%2E%2C and M�ndez%2C B%2E %281998%29%2E Isolation%2C characterisation and determination of biological activity of coffee proanthocyanidins%2E Journal of the Science of Food and Agriculture 77%2C 368%2D372%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=de Colmenares, N.G., Ram�rez-Mart�nez, J.R., Aldana, J.O., Ramos-Ni�o, M.E., Clifford, M.N., P�kerar, S., and M�ndez, B. (1998). Isolation, characterisation and determination of biological activity of coffee proanthocyanidins. Journal of the Science of Food and Agriculture 77, 368-372.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=de&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Isolation, characterisation and determination of biological activity of coffee proanthocyanidins&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Isolation, characterisation and determination of biological activity of coffee proanthocyanidins&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=de&as_ylo=1998&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Debeaujon%2C I%2E%2C Nesi%2C N%2E%2C Perez%2C P%2E%2C Devic%2C M%2E%2C Grandjean%2C O%2E%2C Caboche%2C M%2E%2C and Lepiniec%2C L%2E %282003%29%2E Proanthocyanidin%2Daccumulating cells in Arabidopsis testa%3A regulation of differentiation and role in seed development%2E Plant Cell 15%2C 2514%2D2531%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Debeaujon, I., Nesi, N., Perez, P., Devic, M., Grandjean, O., Caboche, M., and Lepiniec, L. (2003). Proanthocyanidin-accumulating cells in Arabidopsis testa: regulation of differentiation and role in seed development. Plant Cell 15, 2514-2531.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Debeaujon,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Proanthocyanidin-accumulating cells in Arabidopsis testa: regulation of differentiation and role in seed development&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Proanthocyanidin-accumulating cells in Arabidopsis testa: regulation of differentiation and role in seed development&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Debeaujon,&as_ylo=2003&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Dixon%2C R%2EA%2E%2C Xie%2C D%2E%2DY%2E%2C and Sharma%2C S%2EB%2E %282005%29%2E Proanthocyanidins �?? a final frontier in flavonoid research%3F New Phytologist 165%2C 9%2D28%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Dixon, R.A., Xie, D.-Y., and Sharma, S.B. (2005). Proanthocyanidins ? a final frontier in flavonoid research? New Phytologist 165, 9-28.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Dixon,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Proanthocyanidins â�?�? a final frontier in flavonoid research&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Proanthocyanidins â�?�? a final frontier in flavonoid research&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Dixon,&as_ylo=2005&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Dixon%2C R%2EA%2E%2C Liu%2C C%2E%2C and Jun%2C J%2EH%2E %282013%29%2E Metabolic engineering of anthocyanins and condensed tannins in plants%2E Current Opinion in Biotechnology 24%2C 329%2D335%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Dixon, R.A., Liu, C., and Jun, J.H. (2013). Metabolic engineering of anthocyanins and condensed tannins in plants. Current Opinion in Biotechnology 24, 329-335.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Dixon,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Metabolic engineering of anthocyanins and condensed tannins in plants&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Metabolic engineering of anthocyanins and condensed tannins in plants&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Dixon,&as_ylo=2013&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Duplessis%2C S%2E%2C Major%2C I%2E%2C Martin%2C F%2E%2C and S�guin%2C A%2E %282009%29%2E Poplar and Pathogen Interactions%3A Insights from Populus Genome%2DWide Analyses of Resistance and Defense Gene Families and Gene Expression Profiling%2E Critical Reviews in Plant Sciences 28%2C 309%2D334%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Duplessis, S., Major, I., Martin, F., and S�guin, A. (2009). Poplar and Pathogen Interactions: Insights from Populus Genome-Wide Analyses of Resistance and Defense Gene Families and Gene Expression Profiling. Critical Reviews in Plant Sciences 28, 309-334.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Duplessis,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Poplar and Pathogen Interactions: Insights from Populus Genome-Wide Analyses of Resistance and Defense Gene Families and Gene Expression Profiling&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Poplar and Pathogen Interactions: Insights from Populus Genome-Wide Analyses of Resistance and Defense Gene Families and Gene Expression Profiling&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Duplessis,&as_ylo=2009&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Duplessis%2C S%2E%2C Cuomo%2C C%2EA%2E%2C Lin%2C Y%2EC%2E%2C Aerts%2C A%2E%2C Tisserant%2C E%2E%2C et al%2E %282011%29%2E Obligate biotrophy features unraveled by the genomic analysis of rust fungi%2E Proc Natl Acad Sci U S A 108%2C 9166%2D9171%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Duplessis, S., Cuomo, C.A., Lin, Y.C., Aerts, A., Tisserant, E., et al. (2011). Obligate biotrophy features unraveled by the genomic analysis of rust fungi. Proc Natl Acad Sci U S A 108, 9166-9171.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Duplessis,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Obligate biotrophy features unraveled by the genomic analysis of rust fungi&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Obligate biotrophy features unraveled by the genomic analysis of rust fungi&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Duplessis,&as_ylo=2011&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Ferreira%2C D%2E%2C and Slade%2C D%2E %282002%29%2E Oligomeric proanthocyanidins%3A naturally occurring O%2Dheterocycles%2E Nat Prod Rep 19%2C 517%2D541%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Ferreira, D., and Slade, D. (2002). Oligomeric proanthocyanidins: naturally occurring O-heterocycles. Nat Prod Rep 19, 517-541.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Ferreira,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Oligomeric proanthocyanidins: naturally occurring O-heterocycles&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Oligomeric proanthocyanidins: naturally occurring O-heterocycles&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Ferreira,&as_ylo=2002&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Fischer%2C T%2EC%2E%2C Halbwirth%2C H%2E%2C Meisel%2C B%2E%2C Stich%2C K%2E%2C and Forkmann%2C G%2E %282003%29%2E Molecular cloning%2C substrate specificity of the functionally expressed dihydroflavonol 4%2Dreductases from Malus domestica and Pyrus communis cultivars and the consequences for flavonoid metabolism%2E Arch Biochem Biophys 412%2C 223%2D230%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Fischer, T.C., Halbwirth, H., Meisel, B., Stich, K., and Forkmann, G. (2003). Molecular cloning, substrate specificity of the functionally expressed dihydroflavonol 4-reductases from Malus domestica and Pyrus communis cultivars and the consequences for flavonoid metabolism. Arch Biochem Biophys 412, 223-230.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Fischer,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Molecular cloning, substrate specificity of the functionally expressed dihydroflavonol 4-reductases from Malus domestica and Pyrus communis cultivars and the consequences for flavonoid metabolism&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Molecular cloning, substrate specificity of the functionally expressed dihydroflavonol 4-reductases from Malus domestica and Pyrus communis cultivars and the consequences for flavonoid metabolism&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Fischer,&as_ylo=2003&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Guindon%2C S%2E%2C Dufayard%2C J%2EF%2E%2C Lefort%2C V%2E%2C Anisimova%2C M%2E%2C Hordijk%2C W%2E%2C and Gascuel%2C O%2E %282010%29%2E New algorithms and methods to estimate maximum%2Dlikelihood phylogenies%3A assessing the performance of PhyML 3%2E0%2E Syst Biol 59%2C 307%2D321%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Guindon, S., Dufayard, J.F., Lefort, V., Anisimova, M., Hordijk, W., and Gascuel, O. (2010). New algorithms and methods to estimate maximum-likelihood phylogenies: assessing the performance of PhyML 3.0. Syst Biol 59, 307-321.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Guindon,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=New algorithms and methods to estimate maximum-likelihood phylogenies: assessing the performance of PhyML 3&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=New algorithms and methods to estimate maximum-likelihood phylogenies: assessing the performance of PhyML 3&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Guindon,&as_ylo=2010&as_allsubj=all&hl=en&c2coff=1


genomics and transcriptomics. J Pathog 2011, 716041.Pubmed: Author and TitleCrossRef: Author and TitleGoogle Scholar: Author Only Title Only Author and Title

Hakulinen, J., Sorjonen, S., and Julkunen-Tiitto, R. (1999). Leaf phenolics of three willow clones differing in resistance to Melampsorarust infection. Physiologia Plantarum 105, 662-669.


Hammerbacher, A., Paetz, C., Wright, L.P., Fischer, T.C., Bohlmann, J., Davis, A.J., Fenning, T.M., Gershenzon, J., and Schmidt, A.(2014). Flavan-3-ols in Norway spruce: biosynthesis, accumulation, and function in response to attack by the bark beetle-associatedfungus Ceratocystis polonica. Plant Physiol 164, 2107-2122.


Hammerbacher, A., Schmidt, A., Wadke, N., Wright, L.P., Schneider, B., Bohlmann, J., Brand, W.A., Fenning, T.M., Gershenzon, J., andPaetz, C. (2013). A common fungal associate of the spruce bark beetle metabolizes the stilbene defenses of Norway spruce. PlantPhysiol 162, 1324-1336.


Hemming, J.D.C., and Lindroth, R.L. (1995). Intraspecific variation in aspen phytochemistry: effects on performance of gypsy moths andforest tent caterpillars. Oecologia 103, 79-88.


Henriquez, M.A., Adam, L.R., and Daayf, F. (2012). Alteration of secondary metabolites' profiles in potato leaves in response to weaklyand highly aggressive isolates of Phytophthora infestans. Plant Physiol Biochem 57, 8-14.


Irmisch, S., Clavijo McCormick, A., Boeckler, G.A., Schmidt, A., Reichelt, M., Schneider, B., Block, K., Schnitzler, J.P., Gershenzon, J.,Unsicker, S.B., and Kollner, T.G. (2013). Two herbivore-induced cytochrome P450 enzymes CYP79D6 and CYP79D7 catalyze theformation of volatile aldoximes involved in poplar defense. Plant Cell 25, 4737-4754.


Irmisch, S., Clavijo McCormick, A., Günther, J., Schmidt, A., Boeckler, G.A., Gershenzon, J., Unsicker, S.B., and Köllner, T.G. (2014).Herbivore-induced poplar cytochrome P450 enzymes of the CYP71 family convert aldoximes to nitriles which repel a generalistcaterpillar. The Plant Journal 80, 1095-1107.


Jansson, S., and Douglas, C.J. (2007). Populus: a model system for plant biology. Annu Rev Plant Biol 58, 435-458.Pubmed: Author and TitleCrossRef: Author and TitleGoogle Scholar: Author Only Title Only Author and Title

Jun, J.H., Liu, C., Xiao, X., and Dixon, R.A. (2015). The Transcriptional Repressor MYB2 Regulates Both Spatial and Temporal Patternsof Proanthocyandin and Anthocyanin Pigmentation in Medicago truncatula. Plant Cell 27, 2860-2879.


Katoh, K., and Standley, D.M. (2013). MAFFT multiple sequence alignment software version 7: improvements in performance andusability. Mol Biol Evol 30, 772-780.


Kao, Y.Y., Harding, S.A., and Tsai, C.J. (2002). Differential expression of two distinct phenylalanine ammonia-lyase genes in condensedtannin-accumulating and lignifying cells of quaking aspen. Plant Physiol 130, 796-807.


Kelm, M.A., Johnson, J.C., Robbins, R.J., Hammerstone, J.F., and Schmitz, H.H. (2006). High-performance liquid chromatography www.plantphysiol.orgon March 18, 2020 - Published by Downloaded from


http://www.ncbi.nlm.nih.gov/pubmed?term=Hacquard%2C S%2E%2C Petre%2C B%2E%2C Frey%2C P%2E%2C Hecker%2C A%2E%2C Rouhier%2C N%2E%2C and Duplessis%2C S%2E %282011%29%2E The poplar%2Dpoplar rust interaction%3A insights from genomics and transcriptomics%2E J Pathog 2011%2C 716041%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Hacquard, S., Petre, B., Frey, P., Hecker, A., Rouhier, N., and Duplessis, S. (2011). The poplar-poplar rust interaction: insights from genomics and transcriptomics. J Pathog 2011, 716041.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Hacquard,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=The poplar-poplar rust interaction: insights from genomics and transcriptomics&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=The poplar-poplar rust interaction: insights from genomics and transcriptomics&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Hacquard,&as_ylo=2011&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Hakulinen%2C J%2E%2C Sorjonen%2C S%2E%2C and Julkunen%2DTiitto%2C R%2E %281999%29%2E Leaf phenolics of three willow clones differing in resistance to Melampsora rust infection%2E Physiologia Plantarum 105%2C 662%2D669%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Hakulinen, J., Sorjonen, S., and Julkunen-Tiitto, R. (1999). Leaf phenolics of three willow clones differing in resistance to Melampsora rust infection. Physiologia Plantarum 105, 662-669.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Hakulinen,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Leaf phenolics of three willow clones differing in resistance to Melampsora rust infection&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Leaf phenolics of three willow clones differing in resistance to Melampsora rust infection&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Hakulinen,&as_ylo=1999&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Hammerbacher%2C A%2E%2C Paetz%2C C%2E%2C Wright%2C L%2EP%2E%2C Fischer%2C T%2EC%2E%2C Bohlmann%2C J%2E%2C Davis%2C A%2EJ%2E%2C Fenning%2C T%2EM%2E%2C Gershenzon%2C J%2E%2C and Schmidt%2C A%2E %282014%29%2E Flavan%2D3%2Dols in Norway spruce%3A biosynthesis%2C accumulation%2C and function in response to attack by the bark beetle%2Dassociated fungus Ceratocystis polonica%2E Plant Physiol 164%2C 2107%2D2122%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Hammerbacher, A., Paetz, C., Wright, L.P., Fischer, T.C., Bohlmann, J., Davis, A.J., Fenning, T.M., Gershenzon, J., and Schmidt, A. (2014). Flavan-3-ols in Norway spruce: biosynthesis, accumulation, and function in response to attack by the bark beetle-associated fungus Ceratocystis polonica. Plant Physiol 164, 2107-2122.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Hammerbacher,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Flavan-3-ols in Norway spruce: biosynthesis, accumulation, and function in response to attack by the bark beetle-associated fungus Ceratocystis polonica&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Flavan-3-ols in Norway spruce: biosynthesis, accumulation, and function in response to attack by the bark beetle-associated fungus Ceratocystis polonica&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Hammerbacher,&as_ylo=2014&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Hammerbacher%2C A%2E%2C Schmidt%2C A%2E%2C Wadke%2C N%2E%2C Wright%2C L%2EP%2E%2C Schneider%2C B%2E%2C Bohlmann%2C J%2E%2C Brand%2C W%2EA%2E%2C Fenning%2C T%2EM%2E%2C Gershenzon%2C J%2E%2C and Paetz%2C C%2E %282013%29%2E A common fungal associate of the spruce bark beetle metabolizes the stilbene defenses of Norway spruce%2E Plant Physiol 162%2C 1324%2D1336%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Hammerbacher, A., Schmidt, A., Wadke, N., Wright, L.P., Schneider, B., Bohlmann, J., Brand, W.A., Fenning, T.M., Gershenzon, J., and Paetz, C. (2013). A common fungal associate of the spruce bark beetle metabolizes the stilbene defenses of Norway spruce. Plant Physiol 162, 1324-1336.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Hammerbacher,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=A common fungal associate of the spruce bark beetle metabolizes the stilbene defenses of Norway spruce&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=A common fungal associate of the spruce bark beetle metabolizes the stilbene defenses of Norway spruce&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Hammerbacher,&as_ylo=2013&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Hemming%2C J%2ED%2EC%2E%2C and Lindroth%2C R%2EL%2E %281995%29%2E Intraspecific variation in aspen phytochemistry%3A effects on performance of gypsy moths and forest tent caterpillars%2E Oecologia 103%2C 79%2D88%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Hemming, J.D.C., and Lindroth, R.L. (1995). Intraspecific variation in aspen phytochemistry: effects on performance of gypsy moths and forest tent caterpillars. Oecologia 103, 79-88.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Hemming,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Intraspecific variation in aspen phytochemistry: effects on performance of gypsy moths and forest tent caterpillars&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Intraspecific variation in aspen phytochemistry: effects on performance of gypsy moths and forest tent caterpillars&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Hemming,&as_ylo=1995&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Henriquez%2C M%2EA%2E%2C Adam%2C L%2ER%2E%2C and Daayf%2C F%2E %282012%29%2E Alteration of secondary metabolites%27 profiles in potato leaves in response to weakly and highly aggressive isolates of Phytophthora infestans%2E Plant Physiol Biochem 57%2C 8%2D14%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Henriquez, M.A., Adam, L.R., and Daayf, F. (2012). Alteration of secondary metabolites' profiles in potato leaves in response to weakly and highly aggressive isolates of Phytophthora infestans. Plant Physiol Biochem 57, 8-14.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Henriquez,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Alteration of secondary metabolites' profiles in potato leaves in response to weakly and highly aggressive isolates of Phytophthora infestans&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Alteration of secondary metabolites' profiles in potato leaves in response to weakly and highly aggressive isolates of Phytophthora infestans&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Henriquez,&as_ylo=2012&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Irmisch%2C S%2E%2C Clavijo McCormick%2C A%2E%2C Boeckler%2C G%2EA%2E%2C Schmidt%2C A%2E%2C Reichelt%2C M%2E%2C Schneider%2C B%2E%2C Block%2C K%2E%2C Schnitzler%2C J%2EP%2E%2C Gershenzon%2C J%2E%2C Unsicker%2C S%2EB%2E%2C and Kollner%2C T%2EG%2E %282013%29%2E Two herbivore%2Dinduced cytochrome P450 enzymes CYP79D6 and CYP79D7 catalyze the formation of volatile aldoximes involved in poplar defense%2E Plant Cell 25%2C 4737%2D4754%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Irmisch, S., Clavijo McCormick, A., Boeckler, G.A., Schmidt, A., Reichelt, M., Schneider, B., Block, K., Schnitzler, J.P., Gershenzon, J., Unsicker, S.B., and Kollner, T.G. (2013). Two herbivore-induced cytochrome P450 enzymes CYP79D6 and CYP79D7 catalyze the formation of volatile aldoximes involved in poplar defense. Plant Cell 25, 4737-4754.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Irmisch,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Two herbivore-induced cytochrome P450 enzymes CYP79D6 and CYP79D7 catalyze the formation of volatile aldoximes involved in poplar defense&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Two herbivore-induced cytochrome P450 enzymes CYP79D6 and CYP79D7 catalyze the formation of volatile aldoximes involved in poplar defense&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Irmisch,&as_ylo=2013&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Irmisch%2C S%2E%2C Clavijo McCormick%2C A%2E%2C G�nther%2C J%2E%2C Schmidt%2C A%2E%2C Boeckler%2C G%2EA%2E%2C Gershenzon%2C J%2E%2C Unsicker%2C S%2EB%2E%2C and K�llner%2C T%2EG%2E %282014%29%2E Herbivore%2Dinduced poplar cytochrome P450 enzymes of the CYP71 family convert aldoximes to nitriles which repel a generalist caterpillar%2E The Plant Journal 80%2C 1095%2D1107%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Irmisch, S., Clavijo McCormick, A., G�nther, J., Schmidt, A., Boeckler, G.A., Gershenzon, J., Unsicker, S.B., and K�llner, T.G. (2014). Herbivore-induced poplar cytochrome P450 enzymes of the CYP71 family convert aldoximes to nitriles which repel a generalist caterpillar. The Plant Journal 80, 1095-1107.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Irmisch,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Herbivore-induced poplar cytochrome P450 enzymes of the CYP71 family convert aldoximes to nitriles which repel a generalist caterpillar&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Herbivore-induced poplar cytochrome P450 enzymes of the CYP71 family convert aldoximes to nitriles which repel a generalist caterpillar&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Irmisch,&as_ylo=2014&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Jansson%2C S%2E%2C and Douglas%2C C%2EJ%2E %282007%29%2E Populus%3A a model system for plant biology%2E Annu Rev Plant Biol 58%2C 435%2D458%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Jansson, S., and Douglas, C.J. (2007). Populus: a model system for plant biology. Annu Rev Plant Biol 58, 435-458.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Jansson,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Populus: a model system for plant biology&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Populus: a model system for plant biology&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Jansson,&as_ylo=2007&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Jun%2C J%2EH%2E%2C Liu%2C C%2E%2C Xiao%2C X%2E%2C and Dixon%2C R%2EA%2E %282015%29%2E The Transcriptional Repressor MYB2 Regulates Both Spatial and Temporal Patterns of Proanthocyandin and Anthocyanin Pigmentation in Medicago truncatula%2E Plant Cell 27%2C 2860%2D2879%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Jun, J.H., Liu, C., Xiao, X., and Dixon, R.A. (2015). The Transcriptional Repressor MYB2 Regulates Both Spatial and Temporal Patterns of Proanthocyandin and Anthocyanin Pigmentation in Medicago truncatula. Plant Cell 27, 2860-2879.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Jun,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=The Transcriptional Repressor MYB2 Regulates Both Spatial and Temporal Patterns of Proanthocyandin and Anthocyanin Pigmentation in Medicago truncatula&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=The Transcriptional Repressor MYB2 Regulates Both Spatial and Temporal Patterns of Proanthocyandin and Anthocyanin Pigmentation in Medicago truncatula&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Jun,&as_ylo=2015&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Katoh%2C K%2E%2C and Standley%2C D%2EM%2E %282013%29%2E MAFFT multiple sequence alignment software version 7%3A improvements in performance and usability%2E Mol Biol Evol 30%2C 772%2D780%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Katoh, K., and Standley, D.M. (2013). MAFFT multiple sequence alignment software version 7: improvements in performance and usability. Mol Biol Evol 30, 772-780.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Katoh,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=MAFFT multiple sequence alignment software version 7: improvements in performance and usability&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=MAFFT multiple sequence alignment software version 7: improvements in performance and usability&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Katoh,&as_ylo=2013&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Kao%2C Y%2EY%2E%2C Harding%2C S%2EA%2E%2C and Tsai%2C C%2EJ%2E %282002%29%2E Differential expression of two distinct phenylalanine ammonia%2Dlyase genes in condensed tannin%2Daccumulating and lignifying cells of quaking aspen%2E Plant Physiol 130%2C 796%2D807%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Kao, Y.Y., Harding, S.A., and Tsai, C.J. (2002). Differential expression of two distinct phenylalanine ammonia-lyase genes in condensed tannin-accumulating and lignifying cells of quaking aspen. Plant Physiol 130, 796-807.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Kao,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Differential expression of two distinct phenylalanine ammonia-lyase genes in condensed tannin-accumulating and lignifying cells of quaking aspen&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Differential expression of two distinct phenylalanine ammonia-lyase genes in condensed tannin-accumulating and lignifying cells of quaking aspen&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Kao,&as_ylo=2002&as_allsubj=all&hl=en&c2coff=1


separation and purification of cacao (Theobroma cacao L.) procyanidins according to degree of polymerization using a diol stationaryphase. J Agric Food Chem 54, 1571-1576.


Koskimäki, J.J., Hokkanen, J., Jaakola, L., Suorsa, M., Tolonen, A., Mattila, S., Pirttilä, A.M., and Hohtola, A. (2009). Flavonoidbiosynthesis and degradation play a role in early defence responses of bilberry (Vaccinium myrtillus) against biotic stress. EuropeanJournal of Plant Pathology 125, 629-640.


Kosonen, M., Keski-Saari, S., Ruuhola, T., Constabel, C.P., and Julkunen-Tiitto, R. (2012). Effects of overproduction of condensedtannins and elevated temperature on chemical and ecological traits of genetically modified hybrid aspens (Populus tremula x P.tremuloides). J Chem Ecol 38, 1235-1246.


Kutchan, T., Gershenzon, J., Moller, B. L., & Gang, D. (2015). Natural products. In Biochemistry and Molecular Biology of Plants., B.B.Buchanan, W. Gruissem & R. L. Jones, ed (Oxford: John Wiley & Sons), pp. 1132-1206.


Lattanzio, V., Lattanzio, V.M., and Cardinali, A. (2006). Role of phenolics in the resistance mechanisms of plants against fungalpathogens and insects. Phytochemistry: Advances in research 661, 23-67.


Le, S.Q., and Gascuel, O. (2008). An improved general amino acid replacement matrix. Mol Biol Evol 25, 1307-1320.Pubmed: Author and TitleCrossRef: Author and TitleGoogle Scholar: Author Only Title Only Author and Title

Levee, V., Major, I., Levasseur, C., Tremblay, L., MacKay, J., and Seguin, A. (2009). Expression profiling and functional analysis ofPopulus WRKY23 reveals a regulatory role in defense. New Phytol 184, 48-70.


Liao, L., Vimolmangkang, S., Wei, G., Zhou, H., Korban, S.S., and Han, Y. (2015). Molecular characterization of genes encodingleucoanthocyanidin reductase involved in proanthocyanidin biosynthesis in apple. Frontiers in Plant Science 6-243.


Lindroth, R.L., Hwang, S.Y. (1996). Diversity, redundancy, and multiplicity in chemical defense systems of aspen. In PhytochemicalDiversity and Redundancy in Ecological Interactions, J.T. Romeo, Saunders, J.A., Barbosa, P., ed (New York: Plenum Press), pp. 25–56.


Liu, C., Wang, X., Shulaev, V., and Dixon, R.A. (2016). A role for leucoanthocyanidin reductase in the extension of proanthocyanidins.Nat Plants 2, 16182.


Massad, T.J., Trumbore, S.E., Ganbat, G., Reichelt, M., Unsicker, S., Boeckler, A., Gleixner, G., Gershenzon, J., and Ruehlow, S. (2014).An optimal defense strategy for phenolic glycoside production in Populus trichocarpa-isotope labeling demonstrates secondarymetabolite production in growing leaves. New Phytol 203, 607-619.


Meilan, R., and Ma, C. , Vol. 344: , 2nd ed., , ed, and ( ), p. (2006). Populus. In Methods in Molecular Biology, K. Wang, ed (Totowa, NJ:Humana Press), pp. 143–152.


Mellway, R.D., Tran, L.T., Prouse, M.B., Campbell, M.M., and Constabel, C.P. (2009). The wound-, pathogen-, and ultraviolet B- www.plantphysiol.orgon March 18, 2020 - Published by Downloaded from


http://www.ncbi.nlm.nih.gov/pubmed?term=Kelm%2C M%2EA%2E%2C Johnson%2C J%2EC%2E%2C Robbins%2C R%2EJ%2E%2C Hammerstone%2C J%2EF%2E%2C and Schmitz%2C H%2EH%2E %282006%29%2E High%2Dperformance liquid chromatography separation and purification of cacao %28Theobroma cacao L%2E%29 procyanidins according to degree of polymerization using a diol stationary phase%2E J Agric Food Chem 54%2C 1571%2D1576%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Kelm, M.A., Johnson, J.C., Robbins, R.J., Hammerstone, J.F., and Schmitz, H.H. (2006). High-performance liquid chromatography separation and purification of cacao (Theobroma cacao L.) procyanidins according to degree of polymerization using a diol stationary phase. J Agric Food Chem 54, 1571-1576.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Kelm,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=High-performance liquid chromatography separation and purification of cacao (Theobroma cacao L&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=High-performance liquid chromatography separation and purification of cacao (Theobroma cacao L&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Kelm,&as_ylo=2006&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Koskim�ki%2C J%2EJ%2E%2C Hokkanen%2C J%2E%2C Jaakola%2C L%2E%2C Suorsa%2C M%2E%2C Tolonen%2C A%2E%2C Mattila%2C S%2E%2C Pirttil�%2C A%2EM%2E%2C and Hohtola%2C A%2E %282009%29%2E Flavonoid biosynthesis and degradation play a role in early defence responses of bilberry %28Vaccinium myrtillus%29 against biotic stress%2E European Journal of Plant Pathology 125%2C 629%2D640%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Koskim�ki, J.J., Hokkanen, J., Jaakola, L., Suorsa, M., Tolonen, A., Mattila, S., Pirttil�, A.M., and Hohtola, A. (2009). Flavonoid biosynthesis and degradation play a role in early defence responses of bilberry (Vaccinium myrtillus) against biotic stress. European Journal of Plant Pathology 125, 629-640.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Koskimäki,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Flavonoid biosynthesis and degradation play a role in early defence responses of bilberry (Vaccinium myrtillus) against biotic stress&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Flavonoid biosynthesis and degradation play a role in early defence responses of bilberry (Vaccinium myrtillus) against biotic stress&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Koskimäki,&as_ylo=2009&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Kosonen%2C M%2E%2C Keski%2DSaari%2C S%2E%2C Ruuhola%2C T%2E%2C Constabel%2C C%2EP%2E%2C and Julkunen%2DTiitto%2C R%2E %282012%29%2E Effects of overproduction of condensed tannins and elevated temperature on chemical and ecological traits of genetically modified hybrid aspens %28Populus tremula x P%2E tremuloides%29%2E J Chem Ecol 38%2C 1235%2D1246%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Kosonen, M., Keski-Saari, S., Ruuhola, T., Constabel, C.P., and Julkunen-Tiitto, R. (2012). Effects of overproduction of condensed tannins and elevated temperature on chemical and ecological traits of genetically modified hybrid aspens (Populus tremula x P. tremuloides). J Chem Ecol 38, 1235-1246.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Kosonen,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Effects of overproduction of condensed tannins and elevated temperature on chemical and ecological traits of genetically modified hybrid aspens (Populus tremula x P&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Effects of overproduction of condensed tannins and elevated temperature on chemical and ecological traits of genetically modified hybrid aspens (Populus tremula x P&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Kosonen,&as_ylo=2012&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Kutchan%2C T%2E%2C Gershenzon%2C J%2E%2C Moller%2C B%2E L%2E%2C %26 Gang%2C D%2E %282015%29%2E Natural products%2E In Biochemistry and Molecular Biology of Plants%2E%2C B%2EB%2E Buchanan%2C W%2E Gruissem %26 R%2E L%2E Jones%2C ed %28Oxford%3A John Wiley %26 Sons%29%2C pp%2E 1132%2D1206%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Kutchan, T., Gershenzon, J., Moller, B. L., & Gang, D. (2015). Natural products. In Biochemistry and Molecular Biology of Plants., B.B. Buchanan, W. Gruissem & R. L. Jones, ed (Oxford: John Wiley & Sons), pp. 1132-1206.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Kutchan,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Natural products.&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Natural products.&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Kutchan,&as_ylo=2015&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Lattanzio%2C V%2E%2C Lattanzio%2C V%2EM%2E%2C and Cardinali%2C A%2E %282006%29%2E Role of phenolics in the resistance mechanisms of plants against fungal pathogens and insects%2E Phytochemistry%3A Advances in research 661%2C 23%2D67%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Lattanzio, V., Lattanzio, V.M., and Cardinali, A. (2006). Role of phenolics in the resistance mechanisms of plants against fungal pathogens and insects. Phytochemistry: Advances in research 661, 23-67.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Lattanzio,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Role of phenolics in the resistance mechanisms of plants against fungal pathogens and insects&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Role of phenolics in the resistance mechanisms of plants against fungal pathogens and insects&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Lattanzio,&as_ylo=2006&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Le%2C S%2EQ%2E%2C and Gascuel%2C O%2E %282008%29%2E An improved general amino acid replacement matrix%2E Mol Biol Evol 25%2C 1307%2D1320%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Le, S.Q., and Gascuel, O. (2008). An improved general amino acid replacement matrix. Mol Biol Evol 25, 1307-1320.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Le,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=An improved general amino acid replacement matrix&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=An improved general amino acid replacement matrix&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Le,&as_ylo=2008&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Levee%2C V%2E%2C Major%2C I%2E%2C Levasseur%2C C%2E%2C Tremblay%2C L%2E%2C MacKay%2C J%2E%2C and Seguin%2C A%2E %282009%29%2E Expression profiling and functional analysis of Populus WRKY23 reveals a regulatory role in defense%2E New Phytol 184%2C 48%2D70%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Levee, V., Major, I., Levasseur, C., Tremblay, L., MacKay, J., and Seguin, A. (2009). Expression profiling and functional analysis of Populus WRKY23 reveals a regulatory role in defense. New Phytol 184, 48-70.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Levee,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Expression profiling and functional analysis of Populus WRKY23 reveals a regulatory role in defense&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Expression profiling and functional analysis of Populus WRKY23 reveals a regulatory role in defense&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Levee,&as_ylo=2009&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Liao%2C L%2E%2C Vimolmangkang%2C S%2E%2C Wei%2C G%2E%2C Zhou%2C H%2E%2C Korban%2C S%2ES%2E%2C and Han%2C Y%2E %282015%29%2E Molecular characterization of genes encoding leucoanthocyanidin reductase involved in proanthocyanidin biosynthesis in apple%2E Frontiers in Plant Science 6%2D243%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Liao, L., Vimolmangkang, S., Wei, G., Zhou, H., Korban, S.S., and Han, Y. (2015). Molecular characterization of genes encoding leucoanthocyanidin reductase involved in proanthocyanidin biosynthesis in apple. Frontiers in Plant Science 6-243.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Liao,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Molecular characterization of genes encoding leucoanthocyanidin reductase involved in proanthocyanidin biosynthesis in apple.&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Molecular characterization of genes encoding leucoanthocyanidin reductase involved in proanthocyanidin biosynthesis in apple.&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Liao,&as_ylo=2015&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Lindroth%2C R%2EL%2E%2C Hwang%2C S%2EY%2E %281996%29%2E Diversity%2C redundancy%2C and multiplicity in chemical defense systems of aspen%2E In Phytochemical Diversity and Redundancy in Ecological Interactions%2C J%2ET%2E Romeo%2C Saunders%2C J%2EA%2E%2C Barbosa%2C P%2E%2C ed %28New York%3A Plenum Press%29%2C pp%2E 25�??56%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Lindroth, R.L., Hwang, S.Y. (1996). Diversity, redundancy, and multiplicity in chemical defense systems of aspen. In Phytochemical Diversity and Redundancy in Ecological Interactions, J.T. Romeo, Saunders, J.A., Barbosa, P., ed (New York: Plenum Press), pp. 25?56.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Lindroth,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Diversity, redundancy, and multiplicity in chemical defense systems of aspen.&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Diversity, redundancy, and multiplicity in chemical defense systems of aspen.&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Lindroth,&as_ylo=1996&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Liu%2C C%2E%2C Wang%2C X%2E%2C Shulaev%2C V%2E%2C and Dixon%2C R%2EA%2E %282016%29%2E A role for leucoanthocyanidin reductase in the extension of proanthocyanidins%2E Nat Plants 2%2C 16182%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Liu, C., Wang, X., Shulaev, V., and Dixon, R.A. (2016). A role for leucoanthocyanidin reductase in the extension of proanthocyanidins. Nat Plants 2, 16182.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Liu,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=A role for leucoanthocyanidin reductase in the extension of proanthocyanidins&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=A role for leucoanthocyanidin reductase in the extension of proanthocyanidins&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Liu,&as_ylo=2016&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Massad%2C T%2EJ%2E%2C Trumbore%2C S%2EE%2E%2C Ganbat%2C G%2E%2C Reichelt%2C M%2E%2C Unsicker%2C S%2E%2C Boeckler%2C A%2E%2C Gleixner%2C G%2E%2C Gershenzon%2C J%2E%2C and Ruehlow%2C S%2E %282014%29%2E An optimal defense strategy for phenolic glycoside production in Populus trichocarpa%2Disotope labeling demonstrates secondary metabolite production in growing leaves%2E New Phytol 203%2C 607%2D619%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Massad, T.J., Trumbore, S.E., Ganbat, G., Reichelt, M., Unsicker, S., Boeckler, A., Gleixner, G., Gershenzon, J., and Ruehlow, S. (2014). An optimal defense strategy for phenolic glycoside production in Populus trichocarpa-isotope labeling demonstrates secondary metabolite production in growing leaves. New Phytol 203, 607-619.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Massad,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=An optimal defense strategy for phenolic glycoside production in Populus trichocarpa-isotope labeling demonstrates secondary metabolite production in growing leaves&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=An optimal defense strategy for phenolic glycoside production in Populus trichocarpa-isotope labeling demonstrates secondary metabolite production in growing leaves&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Massad,&as_ylo=2014&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Meilan%2C R%2E%2C and Ma%2C C%2E %2C Vol%2E 344%3A %2C 2nd ed%2E%2C %2C ed%2C and %28 %29%2C p%2E %282006%29%2E Populus%2E In Methods in Molecular Biology%2C K%2E Wang%2C ed %28Totowa%2C NJ%3A Humana Press%29%2C pp%2E 143�??152%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Meilan, R., and Ma, C. , Vol. 344: , 2nd ed., , ed, and ( ), p. (2006). Populus. In Methods in Molecular Biology, K. Wang, ed (Totowa, NJ: Humana Press), pp. 143?152.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Meilan,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Populus.&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Populus.&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Meilan,&as_ylo=2006&as_allsubj=all&hl=en&c2coff=1


responsive MYB134 gene encodes an R2R3 MYB transcription factor that regulates proanthocyanidin synthesis in poplar. PlantPhysiol 150, 924-941.


Miranda, M., Ralph, S.G., Mellway, R., White, R., Heath, M.C., Bohlmann, J., and Constabel, C.P. (2007). The transcriptional response ofhybrid poplar (Populus trichocarpa x P. deltoides) to infection by Melampsora medusae leaf rust involves induction of flavonoidpathway genes leading to the accumulation of proanthocyanidins. Mol Plant Microbe Interact 20, 816-831.


Nemesio-Gorriz, M., Hammerbacher, A., Ihrmark, K., Kallman, T., Olson, A., Lascoux, M., Stenlid, J., Gershenzon, J., and Elfstrand, M.(2016). Different Alleles of a Gene Encoding Leucoanthocyanidin Reductase (PaLAR3) Influence Resistance against the FungusHeterobasidion parviporum in Picea abies. Plant Physiol 171, 2671-2681.


Newcombe, G. (1996). The specificity of fungal pathogens of Populus. In Biology of Populus and its Implications for Management andConservation. (NRC Research Press, National Research Council of Canada, Ottawa, ON.).


Newcombe, G., Ostry, M., Hubbes, M., P´erinet, P., and Mottet, M.-J. (2001). Poplar diseases. In Poplar culture in North America, D.I.Dickmann, Isebrands, J. G., Eckenwalder, J. E. & Richardson, J., ed (Ottawa, ON, Canada: NRC Res. Press), pp. 249-276.


O’Maille, P.E., Tsai, M.D., Greenhagen, B.T., Chappell, J. and Noel, J.P. . (2004). Gene library synthesis by structure-basedcombinatorial protein engineering. Methods Enzymol., 75–91.


Osbourn, A. (1996). Preformed Antimicrobial Compounds and Plant Defense against Fungal Attack. Plant Cell 8, 1821-1831.Pubmed: Author and TitleCrossRef: Author and TitleGoogle Scholar: Author Only Title Only Author and Title

Palo, R.T. (1984). Distribution of birch (Betula SPP.), willow (Salix SPP.), and poplar (Populus SPP.) secondary metabolites and theirpotential role as chemical defense against herbivores. Journal of Chemical Ecology 10, 499-520.


Pang, Y., Abeysinghe, I.S., He, J., He, X., Huhman, D., Mewan, K.M., Sumner, L.W., Yun, J., and Dixon, R.A. (2013). Functionalcharacterization of proanthocyanidin pathway enzymes from tea and their application for metabolic engineering. Plant Physiol 161,1103-1116.


Paolocci, F., Robbins, M.P., Madeo, L., Arcioni, S., Martens, S., and Damiani, F. (2007). Ectopic expression of a basic helix-loop-helixgene transactivates parallel pathways of proanthocyanidin biosynthesis. structure, expression analysis, and genetic control ofleucoanthocyanidin 4-reductase and anthocyanidin reductase genes in Lotus corniculatus. Plant Physiol 143, 504-516.


Pearl, I.A., and Darling, S.F. (1971). Phenolic extractives of the leaves of Populus balsamifera and of P. trichocarpa. Phytochemistry 10,2844-2847.


Pereira, D., Valentão, P., Pereira, J., and Andrade, P. (2009). Phenolics: From Chemistry to Biology. Molecules 14, 2202.Pubmed: Author and TitleCrossRef: Author and TitleGoogle Scholar: Author Only Title Only Author and Title

Peters, D.J., and Constabel, C.P. (2002). Molecular analysis of herbivore-induced condensed tannin synthesis: cloning and expression www.plantphysiol.orgon March 18, 2020 - Published by Downloaded from


http://www.ncbi.nlm.nih.gov/pubmed?term=Mellway%2C R%2ED%2E%2C Tran%2C L%2ET%2E%2C Prouse%2C M%2EB%2E%2C Campbell%2C M%2EM%2E%2C and Constabel%2C C%2EP%2E %282009%29%2E The wound%2D%2C pathogen%2D%2C and ultraviolet B%2Dresponsive MYB134 gene encodes an R2R3 MYB transcription factor that regulates proanthocyanidin synthesis in poplar%2E Plant Physiol 150%2C 924%2D941%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Mellway, R.D., Tran, L.T., Prouse, M.B., Campbell, M.M., and Constabel, C.P. (2009). The wound-, pathogen-, and ultraviolet B-responsive MYB134 gene encodes an R2R3 MYB transcription factor that regulates proanthocyanidin synthesis in poplar. Plant Physiol 150, 924-941.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Mellway,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=The wound-, pathogen-, and ultraviolet B-responsive MYB134 gene encodes an R2R3 MYB transcription factor that regulates proanthocyanidin synthesis in poplar&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=The wound-, pathogen-, and ultraviolet B-responsive MYB134 gene encodes an R2R3 MYB transcription factor that regulates proanthocyanidin synthesis in poplar&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Mellway,&as_ylo=2009&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Miranda%2C M%2E%2C Ralph%2C S%2EG%2E%2C Mellway%2C R%2E%2C White%2C R%2E%2C Heath%2C M%2EC%2E%2C Bohlmann%2C J%2E%2C and Constabel%2C C%2EP%2E %282007%29%2E The transcriptional response of hybrid poplar %28Populus trichocarpa x P%2E deltoides%29 to infection by Melampsora medusae leaf rust involves induction of flavonoid pathway genes leading to the accumulation of proanthocyanidins%2E Mol Plant Microbe Interact 20%2C 816%2D831%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Miranda, M., Ralph, S.G., Mellway, R., White, R., Heath, M.C., Bohlmann, J., and Constabel, C.P. (2007). The transcriptional response of hybrid poplar (Populus trichocarpa x P. deltoides) to infection by Melampsora medusae leaf rust involves induction of flavonoid pathway genes leading to the accumulation of proanthocyanidins. Mol Plant Microbe Interact 20, 816-831.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Miranda,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=The transcriptional response of hybrid poplar (Populus trichocarpa x P&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=The transcriptional response of hybrid poplar (Populus trichocarpa x P&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Miranda,&as_ylo=2007&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Nemesio%2DGorriz%2C M%2E%2C Hammerbacher%2C A%2E%2C Ihrmark%2C K%2E%2C Kallman%2C T%2E%2C Olson%2C A%2E%2C Lascoux%2C M%2E%2C Stenlid%2C J%2E%2C Gershenzon%2C J%2E%2C and Elfstrand%2C M%2E %282016%29%2E Different Alleles of a Gene Encoding Leucoanthocyanidin Reductase %28PaLAR3%29 Influence Resistance against the Fungus Heterobasidion parviporum in Picea abies%2E Plant Physiol 171%2C 2671%2D2681%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Nemesio-Gorriz, M., Hammerbacher, A., Ihrmark, K., Kallman, T., Olson, A., Lascoux, M., Stenlid, J., Gershenzon, J., and Elfstrand, M. (2016). Different Alleles of a Gene Encoding Leucoanthocyanidin Reductase (PaLAR3) Influence Resistance against the Fungus Heterobasidion parviporum in Picea abies. Plant Physiol 171, 2671-2681.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Nemesio-Gorriz,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Different Alleles of a Gene Encoding Leucoanthocyanidin Reductase (PaLAR3) Influence Resistance against the Fungus Heterobasidion parviporum in Picea abies&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Different Alleles of a Gene Encoding Leucoanthocyanidin Reductase (PaLAR3) Influence Resistance against the Fungus Heterobasidion parviporum in Picea abies&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Nemesio-Gorriz,&as_ylo=2016&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Newcombe%2C G%2E %281996%29%2E The specificity of fungal pathogens of Populus%2E In Biology of Populus and its Implications for Management and Conservation%2E %28NRC Research Press%2C National Research Council of Canada%2C Ottawa%2C ON%2E%29%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Newcombe, G. (1996). The specificity of fungal pathogens of Populus. In Biology of Populus and its Implications for Management and Conservation. (NRC Research Press, National Research Council of Canada, Ottawa, ON.).

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Newcombe,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=The specificity of fungal pathogens of Populus.&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=The specificity of fungal pathogens of Populus.&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Newcombe,&as_ylo=1996&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Newcombe%2C G%2E%2C Ostry%2C M%2E%2C Hubbes%2C M%2E%2C P�erinet%2C P%2E%2C and Mottet%2C M%2E%2DJ%2E %282001%29%2E Poplar diseases%2E In Poplar culture in North America%2C D%2EI%2E Dickmann%2C Isebrands%2C J%2E G%2E%2C Eckenwalder%2C J%2E E%2E %26 Richardson%2C J%2E%2C ed %28Ottawa%2C ON%2C Canada%3A NRC Res%2E Press%29%2C pp%2E 249%2D276%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Newcombe, G., Ostry, M., Hubbes, M., P�erinet, P., and Mottet, M.-J. (2001). Poplar diseases. In Poplar culture in North America, D.I. Dickmann, Isebrands, J. G., Eckenwalder, J. E. & Richardson, J., ed (Ottawa, ON, Canada: NRC Res. Press), pp. 249-276.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Newcombe,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Poplar diseases.&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Poplar diseases.&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Newcombe,&as_ylo=2001&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=O�??Maille%2C P%2EE%2E%2C Tsai%2C M%2ED%2E%2C Greenhagen%2C B%2ET%2E%2C Chappell%2C J%2E and Noel%2C J%2EP%2E %2E %282004%29%2E Gene library synthesis by structure%2Dbased combinatorial protein engineering%2E Methods Enzymol%2E%2C 75�??91%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=O?Maille, P.E., Tsai, M.D., Greenhagen, B.T., Chappell, J. and Noel, J.P. . (2004). Gene library synthesis by structure-based combinatorial protein engineering. Methods Enzymol., 75?91.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Oâ�?�?Maille,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Gene library synthesis by structure-based combinatorial protein engineering.&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Gene library synthesis by structure-based combinatorial protein engineering.&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Oâ�?�?Maille,&as_ylo=2004&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Osbourn%2C A%2E %281996%29%2E Preformed Antimicrobial Compounds and Plant Defense against Fungal Attack%2E Plant Cell 8%2C 1821%2D1831%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Osbourn, A. (1996). Preformed Antimicrobial Compounds and Plant Defense against Fungal Attack. Plant Cell 8, 1821-1831.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Osbourn,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Preformed Antimicrobial Compounds and Plant Defense against Fungal Attack&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Preformed Antimicrobial Compounds and Plant Defense against Fungal Attack&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Osbourn,&as_ylo=1996&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Palo%2C R%2ET%2E %281984%29%2E Distribution of birch %28Betula SPP%2E%29%2C willow %28Salix SPP%2E%29%2C and poplar %28Populus SPP%2E%29 secondary metabolites and their potential role as chemical defense against herbivores%2E Journal of Chemical Ecology 10%2C 499%2D520%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Palo, R.T. (1984). Distribution of birch (Betula SPP.), willow (Salix SPP.), and poplar (Populus SPP.) secondary metabolites and their potential role as chemical defense against herbivores. Journal of Chemical Ecology 10, 499-520.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Palo,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Distribution of birch (Betula SPP&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Distribution of birch (Betula SPP&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Palo,&as_ylo=1984&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Pang%2C Y%2E%2C Abeysinghe%2C I%2ES%2E%2C He%2C J%2E%2C He%2C X%2E%2C Huhman%2C D%2E%2C Mewan%2C K%2EM%2E%2C Sumner%2C L%2EW%2E%2C Yun%2C J%2E%2C and Dixon%2C R%2EA%2E %282013%29%2E Functional characterization of proanthocyanidin pathway enzymes from tea and their application for metabolic engineering%2E Plant Physiol 161%2C 1103%2D1116%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Pang, Y., Abeysinghe, I.S., He, J., He, X., Huhman, D., Mewan, K.M., Sumner, L.W., Yun, J., and Dixon, R.A. (2013). Functional characterization of proanthocyanidin pathway enzymes from tea and their application for metabolic engineering. Plant Physiol 161, 1103-1116.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Pang,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Functional characterization of proanthocyanidin pathway enzymes from tea and their application for metabolic engineering&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Functional characterization of proanthocyanidin pathway enzymes from tea and their application for metabolic engineering&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Pang,&as_ylo=2013&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Paolocci%2C F%2E%2C Robbins%2C M%2EP%2E%2C Madeo%2C L%2E%2C Arcioni%2C S%2E%2C Martens%2C S%2E%2C and Damiani%2C F%2E %282007%29%2E Ectopic expression of a basic helix%2Dloop%2Dhelix gene transactivates parallel pathways of proanthocyanidin biosynthesis%2E structure%2C expression analysis%2C and genetic control of leucoanthocyanidin 4%2Dreductase and anthocyanidin reductase genes in Lotus corniculatus%2E Plant Physiol 143%2C 504%2D516%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Paolocci, F., Robbins, M.P., Madeo, L., Arcioni, S., Martens, S., and Damiani, F. (2007). Ectopic expression of a basic helix-loop-helix gene transactivates parallel pathways of proanthocyanidin biosynthesis. structure, expression analysis, and genetic control of leucoanthocyanidin 4-reductase and anthocyanidin reductase genes in Lotus corniculatus. Plant Physiol 143, 504-516.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Paolocci,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Ectopic expression of a basic helix-loop-helix gene transactivates parallel pathways of proanthocyanidin biosynthesis&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Ectopic expression of a basic helix-loop-helix gene transactivates parallel pathways of proanthocyanidin biosynthesis&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Paolocci,&as_ylo=2007&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Pearl%2C I%2EA%2E%2C and Darling%2C S%2EF%2E %281971%29%2E Phenolic extractives of the leaves of Populus balsamifera and of P%2E trichocarpa%2E Phytochemistry 10%2C 2844%2D2847%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Pearl, I.A., and Darling, S.F. (1971). Phenolic extractives of the leaves of Populus balsamifera and of P. trichocarpa. Phytochemistry 10, 2844-2847.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Pearl,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Phenolic extractives of the leaves of Populus balsamifera and of P&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Phenolic extractives of the leaves of Populus balsamifera and of P&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Pearl,&as_ylo=1971&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Pereira%2C D%2E%2C Valent�o%2C P%2E%2C Pereira%2C J%2E%2C and Andrade%2C P%2E %282009%29%2E Phenolics%3A From Chemistry to Biology%2E Molecules 14%2C 2202%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Pereira, D., Valent�o, P., Pereira, J., and Andrade, P. (2009). Phenolics: From Chemistry to Biology. Molecules 14, 2202.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Pereira,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Phenolics: From Chemistry to Biology&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Phenolics: From Chemistry to Biology&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Pereira,&as_ylo=2009&as_allsubj=all&hl=en&c2coff=1


of dihydroflavonol reductase from trembling aspen (Populus tremuloides). Plant J 32, 701-712.Pubmed: Author and TitleCrossRef: Author and TitleGoogle Scholar: Author Only Title Only Author and Title

Pfabel, C., Eckhardt, K.U., Baum, C., Struck, C., Frey, P., and Weih, M. (2012). Impact of ectomycorrhizal colonization and rust infectionon the secondary metabolism of poplar (Populus trichocarpa x deltoides). Tree Physiol 32, 1357-1364.


Porter LJ, Hrstich LN, Chan BG. 1985. The conversion of procyanidins and prodelphinidins to cyanidin and delphinidin. Phytochemistry25(1): 223-230.


Prithiviraj, B., Perry, L.G., Badri, D.V., and Vivanco, J.M. (2007). Chemical facilitation and induced pathogen resistance mediated by aroot-secreted phytotoxin. New Phytol 173, 852-860.


Robinson, B.H., Mills, T.M., Petit, D., Fung, L.E., Green, S.R., and Clothier, B.E. (2000). Natural and induced cadmium-accumulation inpoplar and willow: Implications for phytoremediation. Plant and Soil 227, 301-306.


Schnoor, J.L., Licht, L.A., McCutcheon, S.C., Wolfe, N.L., and Carreira, L.H. (1995). Phytoremediation of Organic and NutrientContaminants. Environmental Science & Technology 29, 318A-323A.


Stanturf, J.A., Van Oosten, C., Netzer, D.A., Coleman, M.D., and Portwood, C.J. (2001). Ecology and silviculture of poplar plantations.Poplar Culture in North America, 153-206.


Stettler, R., Zsuffa, L., and Wu, R. (1996). The role of hybridization in the genetic manipulation of Populus. Biology of Populus and itsimplications for management and conservation, 87-112.


Tanner, G.J., Francki, K.T., Abrahams, S., Watson, J.M., Larkin, P.J., and Ashton, A.R. (2003). Proanthocyanidin biosynthesis in plants.Purification of legume leucoanthocyanidin reductase and molecular cloning of its cDNA. J Biol Chem 278, 31647-31656.


Treutter, D. (2005). Significance of flavonoids in plant resistance and enhancement of their biosynthesis. Plant Biol (Stuttg) 7, 581-591.Pubmed: Author and TitleCrossRef: Author and TitleGoogle Scholar: Author Only Title Only Author and Title

Tsai, C.J., Harding, S.A., Tschaplinski, T.J., Lindroth, R.L., and Yuan, Y. (2006). Genome-wide analysis of the structural genes regulatingdefense phenylpropanoid metabolism in Populus. New Phytol 172, 47-62.


Tuskan, G.A., Difazio, S., Jansson, S., Bohlmann, J., Grigoriev, I., et al. (2006). The genome of black cottonwood, Populus trichocarpa(Torr. & Gray). Science 313, 1596-1604.


Vandeputte, O.M., Kiendrebeogo, M., Rajaonson, S., Diallo, B., Mol, A., El Jaziri, M., and Baucher, M. (2010). Identification of catechin asone of the flavonoids from Combretum albiflorum bark extract that reduces the production of quorum-sensing-controlled virulencefactors in Pseudomonas aeruginosa PAO1. Appl Environ Microbiol 76, 243-253.

Pubmed: Author and TitleCrossRef: Author and Title


http://www.ncbi.nlm.nih.gov/pubmed?term=Peters%2C D%2EJ%2E%2C and Constabel%2C C%2EP%2E %282002%29%2E Molecular analysis of herbivore%2Dinduced condensed tannin synthesis%3A cloning and expression of dihydroflavonol reductase from trembling aspen %28Populus tremuloides%29%2E Plant J 32%2C 701%2D712%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Peters, D.J., and Constabel, C.P. (2002). Molecular analysis of herbivore-induced condensed tannin synthesis: cloning and expression of dihydroflavonol reductase from trembling aspen (Populus tremuloides). Plant J 32, 701-712.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Peters,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Molecular analysis of herbivore-induced condensed tannin synthesis: cloning and expression of dihydroflavonol reductase from trembling aspen (Populus tremuloides)&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Molecular analysis of herbivore-induced condensed tannin synthesis: cloning and expression of dihydroflavonol reductase from trembling aspen (Populus tremuloides)&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Peters,&as_ylo=2002&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Pfabel%2C C%2E%2C Eckhardt%2C K%2EU%2E%2C Baum%2C C%2E%2C Struck%2C C%2E%2C Frey%2C P%2E%2C and Weih%2C M%2E %282012%29%2E Impact of ectomycorrhizal colonization and rust infection on the secondary metabolism of poplar %28Populus trichocarpa x deltoides%29%2E Tree Physiol 32%2C 1357%2D1364%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Pfabel, C., Eckhardt, K.U., Baum, C., Struck, C., Frey, P., and Weih, M. (2012). Impact of ectomycorrhizal colonization and rust infection on the secondary metabolism of poplar (Populus trichocarpa x deltoides). Tree Physiol 32, 1357-1364.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Pfabel,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Impact of ectomycorrhizal colonization and rust infection on the secondary metabolism of poplar (Populus trichocarpa x deltoides)&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Impact of ectomycorrhizal colonization and rust infection on the secondary metabolism of poplar (Populus trichocarpa x deltoides)&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Pfabel,&as_ylo=2012&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Porter LJ%2C Hrstich LN%2C Chan BG%2E 1985%2E The conversion of procyanidins and prodelphinidins to cyanidin and delphinidin%2E Phytochemistry 25%281%29%3A 223%2D230%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Porter LJ, Hrstich LN, Chan BG. 1985. The conversion of procyanidins and prodelphinidins to cyanidin and delphinidin. Phytochemistry 25(1): 223-230.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Porter&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=The conversion of procyanidins and prodelphinidins to cyanidin and delphinidin&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=The conversion of procyanidins and prodelphinidins to cyanidin and delphinidin&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Porter&as_ylo=1985&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Prithiviraj%2C B%2E%2C Perry%2C L%2EG%2E%2C Badri%2C D%2EV%2E%2C and Vivanco%2C J%2EM%2E %282007%29%2E Chemical facilitation and induced pathogen resistance mediated by a root%2Dsecreted phytotoxin%2E New Phytol 173%2C 852%2D860%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Prithiviraj, B., Perry, L.G., Badri, D.V., and Vivanco, J.M. (2007). Chemical facilitation and induced pathogen resistance mediated by a root-secreted phytotoxin. New Phytol 173, 852-860.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Prithiviraj,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Chemical facilitation and induced pathogen resistance mediated by a root-secreted phytotoxin&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Chemical facilitation and induced pathogen resistance mediated by a root-secreted phytotoxin&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Prithiviraj,&as_ylo=2007&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Robinson%2C B%2EH%2E%2C Mills%2C T%2EM%2E%2C Petit%2C D%2E%2C Fung%2C L%2EE%2E%2C Green%2C S%2ER%2E%2C and Clothier%2C B%2EE%2E %282000%29%2E Natural and induced cadmium%2Daccumulation in poplar and willow%3A Implications for phytoremediation%2E Plant and Soil 227%2C 301%2D306%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Robinson, B.H., Mills, T.M., Petit, D., Fung, L.E., Green, S.R., and Clothier, B.E. (2000). Natural and induced cadmium-accumulation in poplar and willow: Implications for phytoremediation. Plant and Soil 227, 301-306.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Robinson,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Natural and induced cadmium-accumulation in poplar and willow: Implications for phytoremediation&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Natural and induced cadmium-accumulation in poplar and willow: Implications for phytoremediation&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Robinson,&as_ylo=2000&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Schnoor%2C J%2EL%2E%2C Licht%2C L%2EA%2E%2C McCutcheon%2C S%2EC%2E%2C Wolfe%2C N%2EL%2E%2C and Carreira%2C L%2EH%2E %281995%29%2E Phytoremediation of Organic and Nutrient Contaminants%2E Environmental Science %26 Technology 29%2C 318A%2D323A%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Schnoor, J.L., Licht, L.A., McCutcheon, S.C., Wolfe, N.L., and Carreira, L.H. (1995). Phytoremediation of Organic and Nutrient Contaminants. Environmental Science & Technology 29, 318A-323A.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Schnoor,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Phytoremediation of Organic and Nutrient Contaminants&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Phytoremediation of Organic and Nutrient Contaminants&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Schnoor,&as_ylo=1995&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Stanturf%2C J%2EA%2E%2C Van Oosten%2C C%2E%2C Netzer%2C D%2EA%2E%2C Coleman%2C M%2ED%2E%2C and Portwood%2C C%2EJ%2E %282001%29%2E Ecology and silviculture of poplar plantations%2E Poplar Culture in North America%2C 153%2D206%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Stanturf, J.A., Van Oosten, C., Netzer, D.A., Coleman, M.D., and Portwood, C.J. (2001). Ecology and silviculture of poplar plantations. Poplar Culture in North America, 153-206.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Stanturf,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Ecology and silviculture of poplar plantations.&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Ecology and silviculture of poplar plantations.&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Stanturf,&as_ylo=2001&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Stettler%2C R%2E%2C Zsuffa%2C L%2E%2C and Wu%2C R%2E %281996%29%2E The role of hybridization in the genetic manipulation of Populus%2E Biology of Populus and its implications for management and conservation%2C 87%2D112%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Stettler, R., Zsuffa, L., and Wu, R. (1996). The role of hybridization in the genetic manipulation of Populus. Biology of Populus and its implications for management and conservation, 87-112.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Stettler,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=The role of hybridization in the genetic manipulation of Populus.&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=The role of hybridization in the genetic manipulation of Populus.&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Stettler,&as_ylo=1996&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Tanner%2C G%2EJ%2E%2C Francki%2C K%2ET%2E%2C Abrahams%2C S%2E%2C Watson%2C J%2EM%2E%2C Larkin%2C P%2EJ%2E%2C and Ashton%2C A%2ER%2E %282003%29%2E Proanthocyanidin biosynthesis in plants%2E Purification of legume leucoanthocyanidin reductase and molecular cloning of its cDNA%2E J Biol Chem 278%2C 31647%2D31656%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Tanner, G.J., Francki, K.T., Abrahams, S., Watson, J.M., Larkin, P.J., and Ashton, A.R. (2003). Proanthocyanidin biosynthesis in plants. Purification of legume leucoanthocyanidin reductase and molecular cloning of its cDNA. J Biol Chem 278, 31647-31656.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Tanner,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Proanthocyanidin biosynthesis in plants&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Proanthocyanidin biosynthesis in plants&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Tanner,&as_ylo=2003&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Treutter%2C D%2E %282005%29%2E Significance of flavonoids in plant resistance and enhancement of their biosynthesis%2E Plant Biol %28Stuttg%29 7%2C 581%2D591%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Treutter, D. (2005). Significance of flavonoids in plant resistance and enhancement of their biosynthesis. Plant Biol (Stuttg) 7, 581-591.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Treutter,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Significance of flavonoids in plant resistance and enhancement of their biosynthesis&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Significance of flavonoids in plant resistance and enhancement of their biosynthesis&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Treutter,&as_ylo=2005&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Tsai%2C C%2EJ%2E%2C Harding%2C S%2EA%2E%2C Tschaplinski%2C T%2EJ%2E%2C Lindroth%2C R%2EL%2E%2C and Yuan%2C Y%2E %282006%29%2E Genome%2Dwide analysis of the structural genes regulating defense phenylpropanoid metabolism in Populus%2E New Phytol 172%2C 47%2D62%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Tsai, C.J., Harding, S.A., Tschaplinski, T.J., Lindroth, R.L., and Yuan, Y. (2006). Genome-wide analysis of the structural genes regulating defense phenylpropanoid metabolism in Populus. New Phytol 172, 47-62.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Tsai,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Genome-wide analysis of the structural genes regulating defense phenylpropanoid metabolism in Populus&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Genome-wide analysis of the structural genes regulating defense phenylpropanoid metabolism in Populus&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Tsai,&as_ylo=2006&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Tuskan%2C G%2EA%2E%2C Difazio%2C S%2E%2C Jansson%2C S%2E%2C Bohlmann%2C J%2E%2C Grigoriev%2C I%2E%2C et al%2E %282006%29%2E The genome of black cottonwood%2C Populus trichocarpa %28Torr%2E %26 Gray%29%2E Science 313%2C 1596%2D1604%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Tuskan, G.A., Difazio, S., Jansson, S., Bohlmann, J., Grigoriev, I., et al. (2006). The genome of black cottonwood, Populus trichocarpa (Torr. & Gray). Science 313, 1596-1604.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Tuskan,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=The genome of black cottonwood, Populus trichocarpa (Torr&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=The genome of black cottonwood, Populus trichocarpa (Torr&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Tuskan,&as_ylo=2006&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Vandeputte%2C O%2EM%2E%2C Kiendrebeogo%2C M%2E%2C Rajaonson%2C S%2E%2C Diallo%2C B%2E%2C Mol%2C A%2E%2C El Jaziri%2C M%2E%2C and Baucher%2C M%2E %282010%29%2E Identification of catechin as one of the flavonoids from Combretum albiflorum bark extract that reduces the production of quorum%2Dsensing%2Dcontrolled virulence factors in Pseudomonas aeruginosa PAO1%2E Appl Environ Microbiol 76%2C 243%2D253%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Vandeputte, O.M., Kiendrebeogo, M., Rajaonson, S., Diallo, B., Mol, A., El Jaziri, M., and Baucher, M. (2010). Identification of catechin as one of the flavonoids from Combretum albiflorum bark extract that reduces the production of quorum-sensing-controlled virulence factors in Pseudomonas aeruginosa PAO1. Appl Environ Microbiol 76, 243-253.


Google Scholar: Author Only Title Only Author and Title

Wang, L., Jiang, Y., Yuan, L., Lu, W., Yang, L., Karim, A., and Luo, K. (2013). Isolation and characterization of cDNAs encodingleucoanthocyanidin reductase and anthocyanidin reductase from Populus trichocarpa. PLoS One 8, e64664.


Whitham, T.G., Bailey, J.K., Schweitzer, J.A., Shuster, S.M., Bangert, R.K., LeRoy, C.J., Lonsdorf, E.V., Allan, G.J., DiFazio, S.P., Potts,B.M., Fischer, D.G., Gehring, C.A., Lindroth, R.L., Marks, J.C., Hart, S.C., Wimp, G.M., and Wooley, S.C. (2006). A framework forcommunity and ecosystem genetics: from genes to ecosystems. Nat Rev Genet 7, 510-523.


Xie, D.Y., Sharma, S.B., and Dixon, R.A. (2004). Anthocyanidin reductases from Medicago truncatula and Arabidopsis thaliana. ArchBiochem Biophys 422, 91-102.


Yamaji, K., and Ichihara, Y. (2012). The role of catechin and epicatechin in chemical defense against damping-off fungi of current-yearFagus crenata seedlings in natural forest. Forest Pathology 42, 1-7.


Yoshida, K., Ma, D., and Constabel, C.P. (2015). The MYB182 protein down-regulates proanthocyanidin and anthocyanin biosynthesis inpoplar by repressing both structural and regulatory flavonoid genes. Plant Physiol 167, 693-710.


Yuan, L., Wang, L., Han, Z., Jiang, Y., Zhao, L., Liu, H., Yang, L., and Luo, K. (2012). Molecular cloning and characterization of PtrLAR3, agene encoding leucoanthocyanidin reductase from Populus trichocarpa, and its constitutive expression enhances fungal resistance intransgenic plants. J Exp Bot 63, 2513-2524.


Zhang, Y., De Stefano, R., Robine, M., Butelli, E., Bulling, K., Hill, L., Rejzek, M., Martin, C., and Schoonbeek, H.J. (2015). DifferentReactive Oxygen Species Scavenging Properties of Flavonoids Determine Their Abilities to Extend the Shelf Life of Tomato. PlantPhysiol 169, 1568-1583.



http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Vandeputte,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Identification of catechin as one of the flavonoids from Combretum albiflorum bark extract that reduces the production of quorum-sensing-controlled virulence factors in Pseudomonas aeruginosa PAO1&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Identification of catechin as one of the flavonoids from Combretum albiflorum bark extract that reduces the production of quorum-sensing-controlled virulence factors in Pseudomonas aeruginosa PAO1&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Vandeputte,&as_ylo=2010&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Wang%2C L%2E%2C Jiang%2C Y%2E%2C Yuan%2C L%2E%2C Lu%2C W%2E%2C Yang%2C L%2E%2C Karim%2C A%2E%2C and Luo%2C K%2E %282013%29%2E Isolation and characterization of cDNAs encoding leucoanthocyanidin reductase and anthocyanidin reductase from Populus trichocarpa%2E PLoS One 8%2C e64664%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Wang, L., Jiang, Y., Yuan, L., Lu, W., Yang, L., Karim, A., and Luo, K. (2013). Isolation and characterization of cDNAs encoding leucoanthocyanidin reductase and anthocyanidin reductase from Populus trichocarpa. PLoS One 8, e64664.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Wang,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Isolation and characterization of cDNAs encoding leucoanthocyanidin reductase and anthocyanidin reductase from Populus trichocarpa&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Isolation and characterization of cDNAs encoding leucoanthocyanidin reductase and anthocyanidin reductase from Populus trichocarpa&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Wang,&as_ylo=2013&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Whitham%2C T%2EG%2E%2C Bailey%2C J%2EK%2E%2C Schweitzer%2C J%2EA%2E%2C Shuster%2C S%2EM%2E%2C Bangert%2C R%2EK%2E%2C LeRoy%2C C%2EJ%2E%2C Lonsdorf%2C E%2EV%2E%2C Allan%2C G%2EJ%2E%2C DiFazio%2C S%2EP%2E%2C Potts%2C B%2EM%2E%2C Fischer%2C D%2EG%2E%2C Gehring%2C C%2EA%2E%2C Lindroth%2C R%2EL%2E%2C Marks%2C J%2EC%2E%2C Hart%2C S%2EC%2E%2C Wimp%2C G%2EM%2E%2C and Wooley%2C S%2EC%2E %282006%29%2E A framework for community and ecosystem genetics%3A from genes to ecosystems%2E Nat Rev Genet 7%2C 510%2D523%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Whitham, T.G., Bailey, J.K., Schweitzer, J.A., Shuster, S.M., Bangert, R.K., LeRoy, C.J., Lonsdorf, E.V., Allan, G.J., DiFazio, S.P., Potts, B.M., Fischer, D.G., Gehring, C.A., Lindroth, R.L., Marks, J.C., Hart, S.C., Wimp, G.M., and Wooley, S.C. (2006). A framework for community and ecosystem genetics: from genes to ecosystems. Nat Rev Genet 7, 510-523.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Whitham,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=A framework for community and ecosystem genetics: from genes to ecosystems&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=A framework for community and ecosystem genetics: from genes to ecosystems&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Whitham,&as_ylo=2006&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Xie%2C D%2EY%2E%2C Sharma%2C S%2EB%2E%2C and Dixon%2C R%2EA%2E %282004%29%2E Anthocyanidin reductases from Medicago truncatula and Arabidopsis thaliana%2E Arch Biochem Biophys 422%2C 91%2D102%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Xie, D.Y., Sharma, S.B., and Dixon, R.A. (2004). Anthocyanidin reductases from Medicago truncatula and Arabidopsis thaliana. Arch Biochem Biophys 422, 91-102.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Xie,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Anthocyanidin reductases from Medicago truncatula and Arabidopsis thaliana&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Anthocyanidin reductases from Medicago truncatula and Arabidopsis thaliana&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Xie,&as_ylo=2004&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Yamaji%2C K%2E%2C and Ichihara%2C Y%2E %282012%29%2E The role of catechin and epicatechin in chemical defense against damping%2Doff fungi of current%2Dyear Fagus crenata seedlings in natural forest%2E Forest Pathology 42%2C 1%2D7%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Yamaji, K., and Ichihara, Y. (2012). The role of catechin and epicatechin in chemical defense against damping-off fungi of current-year Fagus crenata seedlings in natural forest. Forest Pathology 42, 1-7.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Yamaji,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=The role of catechin and epicatechin in chemical defense against damping-off fungi of current-year Fagus crenata seedlings in natural forest&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=The role of catechin and epicatechin in chemical defense against damping-off fungi of current-year Fagus crenata seedlings in natural forest&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Yamaji,&as_ylo=2012&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Yoshida%2C K%2E%2C Ma%2C D%2E%2C and Constabel%2C C%2EP%2E %282015%29%2E The MYB182 protein down%2Dregulates proanthocyanidin and anthocyanin biosynthesis in poplar by repressing both structural and regulatory flavonoid genes%2E Plant Physiol 167%2C 693%2D710%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Yoshida, K., Ma, D., and Constabel, C.P. (2015). The MYB182 protein down-regulates proanthocyanidin and anthocyanin biosynthesis in poplar by repressing both structural and regulatory flavonoid genes. Plant Physiol 167, 693-710.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Yoshida,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=The MYB182 protein down-regulates proanthocyanidin and anthocyanin biosynthesis in poplar by repressing both structural and regulatory flavonoid genes&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=The MYB182 protein down-regulates proanthocyanidin and anthocyanin biosynthesis in poplar by repressing both structural and regulatory flavonoid genes&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Yoshida,&as_ylo=2015&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Yuan%2C L%2E%2C Wang%2C L%2E%2C Han%2C Z%2E%2C Jiang%2C Y%2E%2C Zhao%2C L%2E%2C Liu%2C H%2E%2C Yang%2C L%2E%2C and Luo%2C K%2E %282012%29%2E Molecular cloning and characterization of PtrLAR3%2C a gene encoding leucoanthocyanidin reductase from Populus trichocarpa%2C and its constitutive expression enhances fungal resistance in transgenic plants%2E J Exp Bot 63%2C 2513%2D2524%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Yuan, L., Wang, L., Han, Z., Jiang, Y., Zhao, L., Liu, H., Yang, L., and Luo, K. (2012). Molecular cloning and characterization of PtrLAR3, a gene encoding leucoanthocyanidin reductase from Populus trichocarpa, and its constitutive expression enhances fungal resistance in transgenic plants. J Exp Bot 63, 2513-2524.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Yuan,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Yuan,&as_ylo=2012&as_allsubj=all&hl=en&c2coff=1

http://www.ncbi.nlm.nih.gov/pubmed?term=Zhang%2C Y%2E%2C De Stefano%2C R%2E%2C Robine%2C M%2E%2C Butelli%2C E%2E%2C Bulling%2C K%2E%2C Hill%2C L%2E%2C Rejzek%2C M%2E%2C Martin%2C C%2E%2C and Schoonbeek%2C H%2EJ%2E %282015%29%2E Different Reactive Oxygen Species Scavenging Properties of Flavonoids Determine Their Abilities to Extend the Shelf Life of Tomato%2E Plant Physiol 169%2C 1568%2D1583%2E&dopt=abstract

http://search.crossref.org/?page=1&rows=2&q=Zhang, Y., De Stefano, R., Robine, M., Butelli, E., Bulling, K., Hill, L., Rejzek, M., Martin, C., and Schoonbeek, H.J. (2015). Different Reactive Oxygen Species Scavenging Properties of Flavonoids Determine Their Abilities to Extend the Shelf Life of Tomato. Plant Physiol 169, 1568-1583.

http://scholar.google.com/scholar?as_q=&num=10&as_occt=any&as_sauthors=Zhang,&hl=en&c2coff=1

http://scholar.google.com/scholar?as_q=Different Reactive Oxygen Species Scavenging Properties of Flavonoids Determine Their Abilities to Extend the Shelf Life of Tomato&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_publication=&as_yhi=&as_allsubj=all&hl=en&lr=&c2coff=1

http://scholar.google.com/scholar?as_q=Different Reactive Oxygen Species Scavenging Properties of Flavonoids Determine Their Abilities to Extend the Shelf Life of Tomato&num=10&btnG=Search+Scholar&as_occt=any&as_sauthors=Zhang,&as_ylo=2015&as_allsubj=all&hl=en&c2coff=1


flavan-3-ols are an effective chemical defense against ... · 1 article title: flavan-3-ols are an...

Documents