Gene symbolLocus tag Protein function Function in root hair

formation Mutant phenotype Reference

Arabidopsis thaliana

BASIC HELIX-LOOP-HELIX 32 (BHLH32), TARGET OF MONOPTEROS 5 (TMO5) AT3G25710 basic helix-loop-helix transcription factor Cell differentiation Changes in number;

Changes in position Chen et al., 2007

CAPRICE (CPC) AT2G46410 transcription factor Cell differentiation Changes in number Wada et al., 1997

CAPRICE-LIKE MYB3 (CPL3), ENHANCER OF TRY AND CPC 3 (ETC3) AT4G01060 myb transcription factor Cell differentiation Changes in number Tominaga et al., 2008

CYSTEINE SYNTHASE C1 (CYSC1), BETA-SUBSTITUTED ALA SYNTHASE 3;1 (BSAS3;1) AT3G61440 cysteine synthase C1 Tip growth Changes in length García et al., 2010

ECTOPIC ROOT HAIR 1 (ERH1), ARABIDOPSIS INOSITOL PHOSPHORYLCERAMIDE SYNTHASE 2 (ATIPCS2) AT2G37940 inositol phosphorylceramide synthase Cell differentiation Changes in position;

Changes in number Schneider et al., 1997

ECTOPIC ROOT HAIR 2 (ERH2), CHITINASE-LIKE PROTEIN 1 (CTL1), ECTOPIC DEPOSITION OF LIGNIN IN PITH 1 AT1G05850 chitinase-like protein Cell differentiation

Changes in number; Changes in position;

Changes in lengthSchneider et al., 1997

ECTOPIC ROOT HAIR 3 (ERH3), BOTERO 1 (BOT1), ECTOPIC ROOT HAIR 3 (ERH3), KATANIN 1 (KTN1), FURCA2 (FRC2), FAT

ROOT (FTR)AT1G80350 p60 katanin Cell differentiation Changes in position Schneider et al., 1997

ENHANCER OF GLABRA3 (EGL3), ATMYC-2 AT1G63650 helix-loop-helix (bHLH) transcriptor factor Cell differentiation Changes in number; Changes in position Zhang et al., 2003

ENHANCER OF TRY AND CPC 1 (ETC1) AT1G01380 MYB transcription factor Cell differentiation No changes Kirik et al., 2004

GL2 EXPRESSION MODULATOR (GEM) AT2G22475 GL2-expression modulator Cell differentiation Changes in number Caro et al., 2007

GLABRA2 (GL2) AT1G79840 homeobox-leucine zipper transcription factor Cell differentiation Changes in number;

Changes in position Rerie et al., 1994

GLABRA3 (GL3), MYC6.2 AT5G41315 basic helix-loop-helix (bHLH1) transcriptor factor Cell differentiation Changes in number;

Changes in position Bernhardt et al., 2003

Supplementary Table 1. The list of the primary root hair genes described in the iRootHair database. Categories of the function in root hair development and mutant phenotypes are indicated instead of full descriptions. Also, only a single, main bibliographic reference is indicated.

GNOM (GN), EMBRYO DEFECTIVE 30 (EMB30), VASCULAR NETWORK 7 (VAN7) AT1G13980 GDP/GTP exchange factor for small G-

proteins of the ADP ribosylation factor (RAF) Cell differentiation Changes in shape; Changes in position Fischer et al., 2006

MYC1, ATMYC1, bHLH12 AT4G00480 basic helix-loop-helix (bHLH) protein Cell differentiation Changes in position Bruex A, et al. 2012

ROOT HAIR DEFECTIVE 6-LIKE 4 (RSL4), bHLH54 AT1G27740 basic helix~loop~helix (bHLH) protein Cell differentiation Changes in position Bruex A, et al. 2012

SALT OVERLY SENSITIVE 4 (SOS4) AT5G37850 pyridoxal kinase Cell differentiation Changes in number Shi et al., 2002

SCRAMBLED (SCM), STRUBBELIG (SUB), STRUBBELIG-RECEPTOR FAMILY 9 (SRF9) AT1G11130 leucine-rich repeat receptor-like kinase Cell differentiation Changes in position Kwak et al., 2005

TRANSPARENT TESTA GLABRA 2 (TTG2), DR. STRANGELOVE 1 (DSL1), WRKY44 AT2G37260 WRKY transcription factor Cell differentiation No changes Johnson et al., 2002

TRANSPARENT TESTA GLABRA1 (TTG1), UNARMED 23 (URM23) AT5G24520 WD40 repeat protein Cell differentiation Changes in number; Changes in position Galway et al., 1994

TRIPTYCHON (TRY) AT5G53200 R3-type MYB transcription factor Cell differentiation No changes Schellmann et al., 2002

WEREWOLF (WER), MYB DOMAIN PROTEIN 66 (MYB66) AT5G14750 transcription factor Cell differentiation Changes in number; Changes in position

Lee and Schiefelbein, 1999

WRKY DNA-BINDING PROTEIN 75 (WRKY75) AT5G13080 WRKY transcription factor Cell differentiation Changes in number Devaiah et al., 2007

AUXIN RESISTANT 2 (AXR2), INDOLE-3-ACETIC ACID 7 (IAA7) AT3G23050 auxin-responsive protein Initiation No changes Nagpal et al., 2000

AUXIN RESISTANT 3 (AXR3), INDOLE-3-ACETIC ACID INDUCIBLE 17 (IAA17) AT1G04250 auxin-responsive protein IAA17 Initiation Root hairless Leyser et al., 1996

ETHYLENE INSENSITIVE 2 (EIN2), CYTOKININ RESISTANT 1 (CKR1), ENHANCED RESPONSE TO ABA3 (ERA3), ORESA AT5G03280 ethylene-insensitive protein Initiation Unknown Pitts et al., 1998

MORPHOGENESIS OF ROOT HAIR 6 (MRH6) AT2G03720 adenine nucleotide alpha hydrolases-like protein Initiation Changes in shape Jones et al., 2006

RHD SIX-LIKE 1 (RSL1), bHLH86 AT5G37800 basic helix-loop-helix (bHLH) protein Initiation No changes Menand et al., 2007

RHO-RELATED PROTEIN FROM PLANTS 2 (ROP2), ARABIDOPSIS RAC-LIKE 4 (ARAC4) AT1G20090 Rac-like GTP-binding protein Initiation

Changes in length; Changes in number; Changes in

shapeJones et al., 2002

ROOT HAIR DEFECTIVE 6 (RHD6) AT1G66470 transcription factor bHLH83 InitiationChanges in number;

Changes in shape; Changes in position

Masucci et al., 1994

ROOT HAIR SPECIFIC 18 (RHS18) AT5G22410 peroxidase Initiation Unknown Won et al., 2009

ROOT HAIR SPECIFIC 19 (RHS19), PEROXIDASE 73 (PER73) AT5G67400 peroxidase Initiation Unknown Won et al., 2009

ROOT HAIRLESS1 (RHL1), HYPOCOTYL 7 (HYP7) AT1G48380 component of the DNA topoisomerase VI complex Initiation Changes in number;

Changes in length Schneider et al., 1997

ROOT HAIRLESS2 (RHL2), BRASSINOSTEROID INSENSITIVE 5 (BIN5) AT5G02820 DNA topoisomerase 6 subunit A Initiation Root hairless Schneider et al., 1997

ROOT HAIRLESS3 (RHL3), BRASSINOSTEROID INSENSITIVE 3 (BIN3), ELONGATED HYPOCOTYL 6 (HYP6), TOPOISOME AT3G20780 DNA topoisomerase 6 subunit B Initiation Root hairless Schneider et al., 1997

S-ADENOSYL-L-HOMOCYSTEIN HYDROLASE 1 (SAHH1), EMBRYO DEFECTIVE 1395 (EMB1395), HOMOLOGY-

DEPENDENT GENE SILENCING 1 (HOG1), MATERNAL EFFECT EMBRYO ARREST 58 (MEE58)

AT4G13940 S-adenosyl-L-homocysteine hydrolase Initiation Root hairless Wu et al., 2009

SHORT HYPOCOTYL 2 (SHY2), INDOLE-3-ACETIC ACID INDUCIBLE 3 (IAA3) AT1G04240 transcription factor, member of the Aux/IAA

gene family Initiation Changes in length; Changes in number Knox et al., 2003

SOLITARYROOT (SLR), INDOLE-3-ACETIC ACID INDUCIBLE 14 (IAA14) AT4G14550 auxin-responsive protein Initiation Changes in number Fukaki et al., 2002

SUPERCENTIPEDE1 (SCN1) AT3G07880 Rho GDP-dissociation inhibitor Initiation Changes in length; Changes in shape Parker et al., 2000

TIP GROWTH DEFECTIVE1 (TIP1) AT5G20350 S-acyltransferase InitiationChanges in length; Changes

in shape; Branched root hairs

Ryan et al., 1998

1-PHOSPHATIDYLINOSITOL-4-PHOSPHATE 5-KINASE 3 (PIP5K3) AT2G26420 phosphatidylinositol-4-phosphate 5-kinase 3 Tip growth Changes in length Kusano et al., 2008

ACTIN 2 (ACT2), DEFORMED ROOT HAIRS 1 (DER1), ENHANCER OF LRX1 2 (ENL2), FRIZZY AND KINKED SHOOTS 2 AT3G18780 actin 2 Tip growth Changes in length; Changes

in shape Ringli et al., 2002

ACTIN INTERACTING PROTEIN 1 (AIP1-1) AT2G01330 actin-interacting protein Tip growth Changes in number; Changes in length Ketelaar et al., 2004

ACTIN INTERACTING PROTEIN 1-2 (AIP1-2) AT3G18060 actin-interacting protein Tip growth Changes in number; Changes in length Ketelaar et al., 2004

ACTIN RELATED PROTEIN 2 (ARP2), WURM (WRM) AT3G27000 actin-related protein Tip growth Changes in shape Mathur et al., 2003

ADP RIBOSILATION FACTOR1 (ARF1) AT1G23490 ADP-ribosylation factor GTPase Tip growth No changes Xu and Scheres, 2005

ADP RIBOSYLATION FACTOR 1 (ARF1A1C) AT2G47170 ADP-ribosylation factor GTPase Tip growth Unknown Xu and Scheres, 2005

AGC2-1, OXIDATIVE SIGNAL-INDUCIBLE1 (OXI1) AT3G25250 serine/threonine-protein kinase OXI1 Tip growth Changes in length Rentel et al., 2004

ARABIDOPSIS K TRANSPORTER 1 (AKT1) AT2G26650 potassium channel protein Tip growth Changes in length Desbrosses et al., 2003

ARABIDOPSIS NPK1-RELATED PROTEIN KINASE 2 (ANP2), MITOGEN-ACTIVATED PROTEIN KINASE KINASE KINASES 2 AT1G54960

kinase belonging to STE Ser/Thr protein kinase family and MAP kinase kinasekinase

subfamilyTip growth Branched root hairs;

Changes in position Beck et al., 2010

ARABIDOPSIS NPK1-RELATED PROTEIN KINASE 3 (ANP3), MAPKKK12 AT3G06030 mitogen-activated protein kinase

kinasekinase Tip growth Branched root hairs; Changes in position Beck et al., 2010

ARABIDOPSIS RAC-LIKE 2 (ARAC2), RHO-RELATED PROTEIN FROM PLANTS 7 (ROP7) AT5G45970 Rac-like GTP-binding protein Tip growth Changes in length Jones et al., 2002

ARF-GAP DOMAIN 1 (AGD1) AT5G61980 adenosine diphosphateribosylation factor-gtpase-activating protein Tip growth Changes in shape; changes

in length Yoo et al., 2008

ARMADILLO REPEAT-CONTAINING KINESIN 1 (ARK1), CA-ROP2 ENHANCER 1 (CAE1), MORPHOGENESIS OF ROOT HAIR AT3G54870 armadillo repeat-containing kinesin-like

protein 1 Tip growth Changes in shape; Branched root hairs Jones et al., 2006

ARP3, DISORTED1 (DIS1) AT1G13180 actin-related protein Tip growth Changes in shape Mathur et al., 2003

AUXIN RESISTANT 1 (AXR1) AT1G05180 NEDD8-activating enzyme E1 regulatory subunit Tip growth Changes in length; Changes

in number Pitts et al., 1998

AUXIN TRANSPORTER PROTEIN 1 (AUX1), MODIFIER OF ARF7/NPH4 PHENOTYPES 1 (MAP1), WAVY ROOTS 5 (WAV5) AT2G38120 auxin transporter protein Tip growth Changes in length Pitts et al., 1998

bHLH84 AT2G14760 basic helix-loop-helix (bHLH) protein Tip growth Branched root hairs; Changes in length Bruex et al., 2012

BIG, CORYMBOSA1 (CRM1), DARK OVER-EXPRESSION OF CAB 1 (DOC1), LOW PHOSPHATE-RESISTANT ROOT 1 (LPR1), AT3G02260 auxin transport protein Tip growth Changes in length Lopez-Bucio et al.,

2005

BRISTLED 1 (BST1), DEFORMED ROOT HAIRS 4 (DER4), MRH3 AT5G65090 inositol-1,4,5 triphosphate 5-phosphatase-like protein Tip growth Changes in length Parker et al., 2000

CAN OF WORMS1 (COW1), SHORT ROOT HAIR 1 (SRH1), ATSFH1 AT4G34580 Sec14p-like phosphatidylinositol transfer

family protein Tip growth Changes in length; Branched root hairs Grierson et al., 1997

CELLULOSE SYNTHASE 6 (CESA6), ISOXABEN RESISTANT 2 (IXR2), PROCUSTE 1 (PRC1) AT5G64740 cellulose synthase A catalytic subunit 6 Tip growth Changes in length; changes

in position Singh et al., 2008

CELLULOSE SYNTHASE-LIKE D2 (CSLD2) AT5G16910 cellulose synthase-like protein D2 Tip growth Changes in length; Changes in shape Bernal et al., 2008

COBRA-LIKE 9 (COBL9), SHAVEN 2 (SHV2), DEFORMED ROOT HAIRS 9 (DER9), MUTANT ROOT HAIR 4 (MRH4) AT5G49270 COBRA-like protein Tip growth Changes in length; Changes

in shape Ringli et al., 2009

CONSTITUTIVE TRIPLE RESPONSE1 (CTR1), SUGAR-INSENSITIVE 1 (SIS1) AT5G03730 RAF-like serine/threonine protein kinase Tip growth Unknown Dolan et al., 1994

CYCLASE ASSOCIATED PROTEIN 1 (CAP1) AT4G34490 cyclase-associated protein Tip growthChanges in length; Changes

in shape; Branched root hairs

Deeks et al., 2007

ECTOPICALLY PARTING CELLS 1 (EPC1) AT3G55830 glycosyltransferase Tip growth Changes in length Bown et al., 2007

ETHYLENE OVERPRODUCER 1 (ETO1) AT3G51770 tetratricopeptide repeat (TPR)-containing protein Tip growth Changes in length Pitts et al., 1998

ETHYLENE RESPONSE 1 (ETR1), ETHYLENE INSENSITIVE 1 (EIN1) AT1G66340 ethylene receptor Tip growth Unknown Dong et al., 2008

EXOCYST SUBUNIT EXO70 FAMILY PROTEIN A1 (EXO70A1) AT5G03540 exocyst subunit exo70 family protein A1 Tip growth Changes in length Synek et al., 2006

EXPANSIN A7 (EXPA7) AT1G12560 expansin A7 Tip growth Changes in length Lin et al., 2011

EXPANSIN A18 (EXPA18) AT1G62980 expansin A18 Tip growth Unknown Cho and Cosgrove, 2002

HEXOKINASE-LIKE 1 (HKL1) AT1G50460 hexokinase Tip growth Changes in shape; Changes in length Karve et al., 2009

INCOMPLETE ROOT HAIR ELONGATION (IRE) AT5G62310 AGC (cAMP-dependent, cGMP-dependent and protein kinase C) kinase family protein Tip growth Changes in length Oyama et al., 2002

INOSITOL POLYPHOSPHATE KINASE 2 ALPHA (IPK2A) AT5G07370 inositol polyphosphate kinase Tip growth Changes in length Xu et al., 2005

INTERACTOR OF CONSTITUTIVE ACTIVE ROPS 1 (ICR1), ROP INTERACTIVE PARTNER 1 (RIP1) AT1G17140 interactor of constitutive active ROPs Tip growth Unknown Lavy et al., 2007

KEULE (KEU) AT1G12360 Sec1 protein Tip growth Changes in shape; Changes in number Assaad et al., 2001

KINKY POLLEN (KIP) AT5G49680 SABRE-like protein Tip growth Changes in length Procissi et l., 2003

KOJAK (KJK), CELLULOSE SYNTHASE LIKE D3 (CSLD3), ROOT HAIR DEFECTIVE 7 (RHD7) AT3G03050 cellulose synthase-like protein D3 Tip growth Changes in length; Changes

in shape Wang et al., 2001

LEUCINE-RICH REPEAT/EXTENSIN 1 (LRX1) AT1G12040 leucine-rich repeat extensin-like protein 1 Tip growth Changes in length; Changes in shape

Baumberger et al., 2001

LEUCINE-RICH REPEAT/EXTENSIN 2 (LRX2) AT1G62440 leucine-rich repeat/extensin 2 Tip growth No changes Baumberger et al., 2003

LJRHL1-LIKE 1 (LRL1), bHLH66 AT2G24260 basic helix-loop-helix (bHLH) protein Tip growth Branched root hairs Bruex et al., 2012

LJRHL1-LIKE 2 (LRL2), bHLH 69 AT4G30980 basic helix-loop-helix (bHLH) protein Tip growth Branched root hairs Bruex et al., 2012

LJRHL1-LIKE 3 (LRL3), bHLH82 AT5G58010 basic helix-loop-helix (bHLH) protein Tip growth Changes in length Bruex et al., 2012

MAP KINASE 4 (MPK4) AT4G01370 mitogen-activated protein kinase Tip growthChanges in shape; Changes in position; Branched root

hairsBeck et al. 2010

MORPHOGENESIS OF ROOT HAIR 1 (MRH1) AT4G18640 LRR receptor-like serine/threonine-protein kinase Tip growth Changes in length; Changes

in shape Jones et al., 2006

MUTANT ROOT HAIR 5 (MRH5), SHAVEN 3 (SHV3), GLYCEROPHOSPHODIESTER PHOSPHODIESTERASE-LIKE 3

(GDPDL3),AT4G26690 glycerophosphoryldiesterphosphodiesterase Tip growth Changes in length; Changes

in shape Jones et al., 2006

MYOSIN 2 (MYA2), ARABIDOPSIS MYOSIN 2 (ATMYA2), MYOSIN X1 2 (XI-2), MYOSIN XI-6 (XI-6) AT5G43900 myosin Tip growth Changes in length Peremyslov et al.,

2008

MYOSIN XI K (XIK) AT5G20490 myosin Tip growth Changes in length Peremyslov et al., 2008

NITRIC OXIDE SYNTHASE 1 (NOS1), NO ASSOCIATED 1 (NOA1), RESISTANT TO INHIBITION WITH FOSMIDOMYCIN 1 AT3G47450 nitric oxide synthase Tip growth Changes in length Lombardo et al., 2006

P-GLYCOPROTEIN 4 (PGP4), ARABIDOPSIS P-GLYCOPROTEIN 4 (ATPGP4), ATP-BINDING CASSETTE B4 (ATABCB4), M AT2G47000 auxin efflux transmembrane transporter Tip growth Changes in length Santelia et al., 2005;

Cho et al., 2007

PHOSPATIDYLINOSITOL 3-KINASE (PI3K), VACUOLAR PROTEIN SORTING 34 (VPS34) AT1G60490 phosphatidylinositol 3-kinase Tip growth Changes in length; Changes

in number Lee et al., 2008

PHOSPHATIDYLINOSITOL 4-OH KINASE BETA1 (PI4KBETA1) AT5G64070 phosphatidylinositol 4-OH kinase B Tip growth No changes Preuss et al., 2006

PROFILIN 1, PFN1, PRF1 AT2G19760 profilin 1 Tip growth Changes in length Ramachandran et al., 2000

PROLINE-RICH EXTENSIN-LIKE RECEPTOR KINASE 13 (PERK13), ROOT HAIR SPECIFIC 10 (RHS10) AT1G70460 proline-rich extensin-like receptor kinase Tip growth Changes in length Won et al., 2009

PROLYL 4-HYDROXYLASE 2 (P4H2) AT3G06300 P4H isoform 2 Tip growth Changes in length; Changes in number Velasquez et al., 2011

PROLYL 4-HYDROXYLASE 5 (P4H5) AT2G17720 2-oxoglutarate (2OG) and Fe(II)-dependent oxygenase-like protein Tip growth Changes in length Velasquez et al., 2011

PROLYL 4-HYDROXYLASE 13 (P4H13) AT2G23096 2-oxoglutarate (2OG) and Fe(II)-dependent oxygenase-like protein Tip growth Changes in length Velasquez et al., 2011

PROLINE-RICH PROTEIN 3 (PRP3) AT3G62680 proline-rich protein Tip growth Unknown Fowler et al., 1999

RAB GTPASE HOMOLOG A4B (RABA4B), GTP-BINDING PROTEIN 3 (GB3) AT4G39990 RabGTPase Tip growth No changes Preuss et al., 2004

REDUCED RESIDUAL ARABINOSE 1 (RRA1) AT1G75120 nucleotide-diphospho-sugar transferase family protein Tip growth Changes in length Egelund et al., 2007

REDUCED RESIDUAL ARABINOSE 2 (RRA2) AT1G75110 nucleotide-diphospho-sugar transferase family protein Tip growth Changes in length Egelund et al., 2007

REDUCED RESIDUAL ARABINOSE 3 (RRA3) AT1G19360 nucleotide-diphospho-sugar transferase family protein Tip growth Changes in length Velasquez et al., 2011

RHO GUANYL-NUCLEOTIDE EXCHANGE FACTOR 4 (ROPGEF4), ROOT HAIR SPECIFIC 11 (RHS11) AT2G45890 Rho guanyl-nucleotide exchange factor

activity Tip growth Changes in length Won et al., 2009

RHO-RELATED PROTEIN FROM PLANTS 4 (ROP4), RAC-LIKE GTP BINDING PROTEIN 5 (RAC5), ARABIDOPSIS THALIANA

GERANYLGERANYLATED PROTEIN 3 (ATGP3)AT1G75840 Rac-like GTP-binding protein Tip growth Changes in shape Molendijk et al., 2001

RHO-RELATED PROTEIN FROM PLANTS 6 (ROP6), RAC-LIKE 3 (RAC3) AT4G35020 Rac-like GTP-binding protein Tip growth Changes in shape Molendijk et al., 2001

ROOT AND POLLEN ARFGAP (RPA), MATERNAL EFFECT EMBRYO ARREST 28 (MEE28) AT2G35210 ADP-ribosylation factor GTPase-activating

protein Tip growthChanges in shape; Changes

in length; Branched root hairs

Song et al., 2006

ROOT HAIR DEFECTIVE 1 (RHD1), ROOT EPIDERMAL BULGER (REB1), UDP-GLUCOSE 4-EPIMERASE (UGE4) AT1G64440 UDP-glucose 4-epimerase Tip growth Changes in length; Changes

in shapeSchiefelbein and Somerville, 1990

ROOT HAIR DEFECTIVE 2 (RHD2), RESPIRATORY BURST OXIDASE HOMOLOG C (RBOHC) AT5G51060 respiratory burst oxidase-C Tip growth Changes in length Schiefelbein and

Somerville, 1990

ROOT HAIR DEFECTIVE 3 (RHD3), GOLGI MUTANT 8 (GOM8) AT3G13870 GTP-binding protein Tip growthChanges in length; Changes

in shape ; Branched root hairs

Schiefelbein and Somerville, 1990

ROOT HAIR DEFECTIVE 4 (RHD4), ATSAC7 AT3G51460 phosphatidylinositol-4-phosphate phosphatase Tip growth Changes in length; Changes

in shapeSchiefelbein and Somerville, 1990

ROOT HAIR DEFECTIVE 6-LIKE 2 (RSL2), bHLH85 AT4G33880 basic helix-loop-helix (bHLH) protein Tip growth Branched root hairs; Changes in length Bruex et al., 2012

ROOT HAIR SPECIFIC 1 (RHS1), CALMODULIN-LIKE PROTEIN 7 (CML7) AT1G05990 calmodulin-like protein 7 Tip growth Changes in length Won et al., 2009

ROOT HAIR SPECIFIC 2 (RHS2) AT1G12950 MATE efflux family protein Tip growth Changes in length Won et al., 2009

ROOT HAIR SPECIFIC 3 (RHS3) AT1G16440 serine/threonine protein kinase Tip growth Changes in shape; Branched root hairs Won et al., 2009

ROOT HAIR SPECIFIC 16 (RHS16) AT4G29180 serine/threonine-protein kinase Tip growth Branched root hairs Won et al., 2009

STOMATAL CYTOKINESIS-DEFECTIVE 1 (SCD1) AT1G49040 protein containing N-terminal DENN domain and eight C-terminal WD-40 repeats Tip growth Changes in length Falbel et al., 2003

SUPPRESSOR OF AUXIN RESISTANCE1 (SAR1), ARABIDOPSIS NUCLEOPORIN 160 (ATNUP160), NUCLEOPORIN 160 (NUP160) AT1G33410 suppressor of auxin resistance1 protein Tip growth Changes in shape; Changes

in number Cernac et al., 1997

TINY ROOT HAIR 1 (TRH1) AT4G23640 potassium transporter Tip growth Changes in length; Changes in shape Rigas et al., 2001

VILLIN 4 (VLN4) AT4G30160 villin, an actin binding protein Tip growth Changes in length Zhang et al., 2011

XYLOGLUCAN XYLOSYLTRANSFERASE 5 (XXT5) AT1G74380 xyloglucan ?-1,6-xylosyltransferase Tip growth Changes in shape Zabotina et al., 2008

GENERAL REGULATORY FACTOR 11 (GRF11), ROOT HAIR SPECIFIC 5 (RHS5) AT1G34760 protein belonging to the 14-3-3 family Unknown Unknown Won et al., 2009

GLYCEROL-3-PHOSPHATE PERMEASE 2 (G3PP2), ROOT HAIR SPECIFIC 15 (RHS15) AT4G25220 glycerol-3-phosphate permease 2 Unknown Unknown Won et al., 2009

METHYL ESTERASE 15 (MES15), ROOT HAIR SPECIFIC 9 (RHS9) AT1G69240 carboxylesterase Unknown Unknown Won et al., 2009

PHYTOCHROME A (PHYA), ELONGATED HYPOCOTYL 8 (HY8), FAR RED ELONGATED 1 (FRE1), FAR RED ELONGATED

HYPOCOTYL 2 (FHY2)AT1G09570 phytochrome A Unknown Changes in number De Simone et al.,

2000

PHYTOCHROME B (PHYB), OUT OF PHASE 1 (OOP1) AT2G18790 phytochrome B Tip growth Changes in length; Changes in number Reed et al., 1993

PROLINE-RICH PROTEIN 1 (PRP1), ROOT HAIR SPECIFIC 7 (RHS7) AT1G54970 proline-rich protein Unknown Unknown Won et al., 2009

ROOT HAIR SPECIFIC 4 (RHS4) AT1G30850 unknown function Unknown Unknown Won et al., 2009

ROOT HAIR SPECIFIC 6 (RHS6) AT1G51880 serine/threonine protein kinase Unknown No changes Won et al., 2009

ROOT HAIR SPECIFIC 8 (RHS8) AT1G63450 exostosin Unknown Unknown Won et al., 2009

ROOT HAIR SPECIFIC 12 (RHS12) AT3G10710 pectinesterase Unknown Unknown Won et al., 2009

ROOT HAIR SPECIFIC 13 (RHS13) AT4G02270 unknown function Unknown Unknown Won et al., 2009

ROOT HAIR SPECIFIC 14 (RHS14) AT4G22080 pectatelyase activity Unknown Unknown Won et al., 2009

ROOT HAIR SPECIFIC 17 (RHS17) AT4G38390 GDP-fucose protein O-fucosyltransferase Unknown Unknown Won et al., 2009

SENESCENCE-ASSOCIATED GENE 21 (SAG21), ARABIDOPSIS THALIANA LATE EMBRYOGENENSIS ABUNDANT LIKE 5

(ATLEA5)AT4G02380 senescence-associated protein Tip growth Changes in length Salleh et al., 2012

TUBULIN ALPHA-6 (TUA6) AT4G14960 tubulin alpha-6 chain Initiation Branched root hairs; Changes in position Bao et al., 2001

UDP-GALACTOSE TRANSPORTER 7 (UTR7) AT4G31600 UDP-N-acetylglucosamine (UAA) transporter family protein Tip growth Changes in length; Changes

in shape Handford et al., 2012

XYLOGLUCAN ENDOTRANSGLYCOSYLASE (XET) AT1G10550 Xyloglucan endotransglucosylase/hydrolase protein Unknown Unknown Vissenberg et al.,

2005

XYLOGLUCANASE 113 (XEG113) AT2G35610 xyloglucanase 113 Tip growth Changes in length Velasquez et al., 2011

Oryza sativa

OsAPY1 Os07g0682800 apyrase Tip growth Changes in length Yuo et al., 2009

OsCSLD1 BK000089 cellulose synthase-like protein D1 Tip growth Changes in length Kim et al., 2007

OsEXPA17 DQ061058 alpha-expansin Tip growth Changes in length ZhiMing et al., 2011

OsEXPA30 AC092697_13 beta expansin Tip growth Unknown ZhiMing et al., 2011

OsEXPB5 Os04g0552200 beta expansin Initiation Unknown Won et al., 2010

OsRHL1 BAD72512 bHLH transcription factor Tip growth Changes in length Ding et al., 2009

Zea mays

ROOTHAIRLESS 1 (RTH1) AY265854 subunit of th the exocyst complex Tip growth Changes in length Wen and Schnable, 1994

ROOTHAIRLESS 3 (RTH3) AY265855 COBRA-like protein Tip growth Changes in length Wen and Schnable, 1994

Hordeum vulgare

BETA-EXPANSIN 1 (EXPB1) AY351786 beta expansin Initiation Unknown Kwasniewski and Szarejko, 2006

Solanum lycopersicum

LeAGP-1 X99148 arabinogalactan Tip growth Unknown Gao et al., 1999

DIF10 X99451 extensin-like protein Tip growth Unknown Bucher et al., 1997

DIF54 X99452 extensin-like protein Tip growth Unknown Bucher et al., 1997

EXTENSIN-LIKE PROTEIN 1 (EXT1), LeEXT1 AJ417830 extensin-like protein Tip growth Unknown Bucher et al., 2002

FER AF437878 bHLH transcriptional regulator Cell differentiation Changes in position; Changes in number Ling et al., 2002

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