bacterial disease of nuts and stone fruits
DESCRIPTION
bacterial disease of nuts and stone fruitsTRANSCRIPT
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COST 873
Stone FruitNut Health
Central Science Laboratory, York, UK
Scientific Training Mission
Bacterial Diseases of Nuts and Stone Fruits
Marco Scortichini
C.R.A.- Centro di Ricerca per la Frutticoltura, Roma, Italy
3-6 March, 2008
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A short survey of the global market of Nut and Stone Fruits
Traditional producers: Turkey, Italy, U.S.A., Spain, France
NUTS
Hazelnut
Emerging countries: Iran, China, Azeirbaijan, Chile
Walnut
Traditional producers: China, U.S.A., Turkey, France,
Italy, Spain
Emerging countries: India, Iran, Chile
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Almond
Traditional producers: U.S.A., Spain, Italy, Greece, Turkey
Emerging countries: India, China
Pistachio
Traditional producers: Iran, U.S.A., Turkey, Syria
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STONE FRUITS
Peach
Traditional countries: China, U.S.A., Mediterranean
Europe
Emerging countries: northern Africa (very early ripening
cultivars)
Apricot
Traditional countries: Europe, U.S.A., Eastern Asia
Emerging countries: Pakistan
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Plum
Traditional producers: China, U.S.A., Serbia, Germany, Romania
Emerging countries: Chile
Cherry
Traditional producers: U.S.A., Turkey, Germany, Italy, Russia
Emerging countries: Iran
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WALNUTXanthomonas arboricola pv. juglandis (Walnut bacterial blight)
- Worldwide distributed
- Limiting factor
- Difficult to control
- Different lineages of the pathogen (vertical oozing canker)
Brenneria nigrifluens (Walnut shallow bark canker)
- Worldwide distributed (suspected)
- Increasing importance
- Difficult to control
Brenneria rubrifaciens (Walnut deep bark canker)
- Apparently limited to California, cv. Hartley
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Xanthomonas arboricola pv. juglandis
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Main features:
- Isolation: easy-to-perform (YDC, GYCA, BS, Tween)
- Pathogenicity tests: need humidity
- Identification: still based on classical techniques
- Characterization: relevant genetic variability (rep-PCR,
AFLP) >>> geographic and/or plant organ structure ??
- Chemical control: copper spray treatments (not always
effective) >>> new compounds
- Occurrence of copper-resistant strains
- Is Xaj pollen-transmitted ?? (just one report)
- Brown apical necrosis (BAN): which role for Xaj ??
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Walnut (Juglans regia L.) in Europe and Eastern Asia: adapted to local
environments
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Isoenzimes + UPGMA
AFLP + Multiple canonical analysis
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Brenneria nigrifluens
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Main features:
- Isolation: not easy (typical symptoms but not isolates on plates)
- Isolation media: NSA, Eosin Blue Agar Medium (Difco)
- Pathogenicity tests: need time to reproduce the symptoms
- Identification: classical (urease test: doubtful) + molecular (rep-PCR)
- Molecular diagnosis: improved but to improve (to verify on
naturally infected samples)
A) 350 bp band, rep-PCR/REP
B) 250 bp, minisatellite M13 phage
- Brenneria: associated with trees >>> pathogenic on stressed plants ??
- Fungi play a role(s) in causing the symptoms ??
- Control: is possible ??
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Brenneria rubrifaciens
Very limited knowledge: is present in Europe ??
Isolation: YDC (pink colour of the agar, not colonies)
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HAZELNUT
Xanthomonas arboricola pv. corylina (Bacterial blight of Hazelnut)
- EPPO Quarantine pest (A2 list)
- Worldwide distributed
- Dangerous on young trees
Pseudomonas avellanae (Bacterial canker and decline of hazelnut)
- Very aggressive in northern Greece and central Italy
- Dangerous on acidic soils
Pseudomonas syringae pv. coryli (Bacterial twig dieback of Hazelnut)
- Known only in Italy and Germany
- Damages to twigs and trunk
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Xanthomonas arboricola pv. corylina
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Main features:
- Isolation: quite effective on GYCA, YDC (no selective media)
- Pathogeniciy tests: need humidity
- Characterization: to improve (limited number of international strains)
- Diagnosis: still based on classical techniques
- Cycle of disease: still largely unknown (role(s) of cankers, fallen
leaves, pollen)
- Control: to improve
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Pseudomonas avellanae
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Main features:
- Isolation: easy on NSA, (no selective media), difficult to maintain
- Pathogenicity tests: to perform in early autumn
- Characterization: relevant information (rep-PCR, ITS, MLST)
- Diagnosis: 16S, hrpW (effective, to improve on plant material)
- Control: copper and S.A.R.-related compound (Bion)
- Effective penetration into the tree via leaf scars
- Two different lineages of the pathogen (Italy and Greece)
- Parallel origin of the two lineages in acidic soils ??
- Is P. avellanae present in other countries ?: Slovenija, Croatia ??
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MLST Genetic distance + Mantel test
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Pseudomonas syringae pv. coryli
- The real distribution is unknwon
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ALMOND
Xanthomonas arboricola pv. pruni (Bacterial spot of Almond)
- EPPO Quarantine pest (A2 list)
- Emerging in mediterranean Europe
- Present in India, Australia, New Zealand, U.S.A.
Pseudomonas amygdali (Bacterial canker of Almond)
- Reported only in Greece (Crete) and Turkey
Xylella fastidiosa (Almond leaf scorch)
- EPPO Quarantine pest (A1 list)
- A threat in California
Agrobacterium tumefaciens (Crown gall of Almond)
- To be checked in the nurseries (rootstocks)
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Xanthomonas arboricola pv. pruni
Very limited knowledge about this pathogen on Almond
(only reports on the occurrence)
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Pseudomonas amygdali
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Xylella fastidiosa
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Agrobacterium (Rhizobium) tumefaciens
Prunus webbii: resistant to artificial inoculation
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PISTACHIO
Xanthomonas translucens pv. poae ?? (Pistachio dieback)
- Recently reported in Australia
- Oozing of resin, xylem staining in 2-3-years old twigs, decline
- Kochs postulate only partially fulfilled
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PEACHXanthomonas arboricola pv. pruni (Bacterial spot of Peach)
- EPPO Quarantine pest (A2 list)
- Increasing importance in Europe
- Spreading mainly through latently infected propagative material
Pseudomonas syringae pv. persicae (Bacterial dieback of Peach)
- EPPO Quarantine pest (A2 list)
- Still limited to France (eradicated ?), England (?) and New Zealand (?)
Pseudomonas syringae pv. syringae (Bacterial canker and fruit scab of Peach)
- It can cause severe damage to fruits
Xylella fastidiosa (Phony Peach)
- EPPO Quarantine pest (A1 list)
- A future threat ?? (global warming + vectors spreading)
Agrobacterium tumefaciens (Peach Crown Gall)
- A problem for the rootstocks
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Xanthomonas arboricola pv. pruni
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Main features:
- Isolation: sometimes difficult (GYCA, YDC, NA)
- Pathogenicity tests: requires humidity and high temperatures (25-28C)
- Identification: combination of classical and molecular techniques
- Characterization: good results (rep-PCR, AFLP) at strain level
- Apparently restricted genetic variability
- Molecular diagnosis: to improve (sensitivity, specificity, vegetative samples)
A) 934 bp: RAPD specific fragment
- Control: difficult (copper phytotoxicity) >>> other compounds
- Biological control: how much is effective ??
- Statistical models for predicting the epidemics
- Role(s) of cankers (when present) in the cycle of disease
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Restricted genetic variability of the host plant
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AFLPfAFLP
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Pseudomonas syringae pv. persicae
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Main features:
- Reported only during the 70s
- Are still there field symptoms of the disease ?
- Not fluorescent on KB medium >>> CSGA
- Ice nucleation-active bacterium
- Predisposing factors: very cold winter, acidic soils, high nitrogen
very heavy soils
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Pseudomonas syringae pv. persicae
RFLP + NJ
France
New
Zealand
UK
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Pseudomonas syringae pv. syringae
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P. syringae pv. syringae
P. syringae pv. persicae
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Main features:
- It occurs occasionally but can be very severe
- It occurs early in the season but symptoms can overlap with those incited by
X. arboricola pv. pruni
- Little knowledge on its cycle of disease
- Control: difficult
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Xylella fastidiosa
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Main features:
- EPPO Quarantine pest (A1 list)
- Very aggressive on Grapevine and Citrus spp.
- There are lineages of the pathogen structured on host plant basis
>>>> subsp. ?, pathovars ?
- Isolation: difficult (long time)
- Pathogenicity tests: difficult (long time)
- Diagnosis: excellent for Grapevine (DAS-ELISA)
- Molecular diagnosis: to validate
A) Grapevine: 733 bp, 1,0 kb-EcoRI fragment
B) Citrus: 500 bp, RAPD specific fragment
- Are there vector(s) in Europe ??
- Could be the pathogen associated with other (European) weeds
and insects ??
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Agrobacterium (Rhizobium) tumefaciens
- A problem in the nursery (GF 305, 677: very sensitive
- Effectiveness of K84 ?
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APRICOT
Xanthomonas arboricola pv. pruni (Bacterial spot of Apricot)
- EPPO Quarantine pest (A2 list)
- Emerging pathogen on this crop (spreading in Europe)
Pseudomonas syringae pv. syringae (Bacterial canker of Apricot)
- It can cause severe damages and the death of the tree
- Some cultivar (i.e. Aurora) are very susceptible
Pseudomonas viridiflava (Bacterial canker of Apricot)
- It can be associated with P. syringae
Agrobacterium (Rhizobium) tumefaciens (Apricot Crown Gall)
- Problem in nursery
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Xanthomonas arboricola pv. pruni
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Pseudomonas syringae pv. syringae
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Main features:
- It is an emerging disease mainly in temperate, non Mediterranean areas
- High susceptibility of the cultivar, spring frost and light soils are very
important predisposing factors
- Different lineages of the pathogen >>> new pathovar ?
- Control: difficult (as for any fruit tree species)
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JAPANESE PLUM
Xanthomonas arboricola pv. pruni (Bacterial spot of Japanese plum)
- EPPO Quarantine pest (A2 list)
- It can be a limiting factor for the cultivation
- Very susceptible cultivars
- Emerging disease
Xylella fastidiosa (Plum Leaf Scald)
- EPPO Quarantine pest (A1 list)
- Very dangerous in the U.S.A.
Agrobacterium (Rhizobium) tumefaciens (Crown Gall of Plum)
- It is a problem in the nursery
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Xanthomonas arboricola pv. pruni
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Xylella fastidiosa
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Agrobacterium (Rhizobium) tumefaciens
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SWEET and SOUR CHERRY
Pseudomonas syringae pv. morsprunorum (Bacterial canker of Cherry)
- Endemic in many areas of cultivation
- Increasing in importance
Pseudomonas syringae pv. syringae (Bacterial canker of Cherry)
- Associated with PSM ??
Pseudomonas syringae pv. avii (Bacterial canker of Cherry)
- Associated with wild Prunus avium ??
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Pseudomonas syringae complex
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Cycle of disease of Pseudomonads
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Main features:
- A Pseudomonas syringae complex
- Increasing importance for timber production and nursery
- Some lineages are associated with organs (i.e. buds, leaves, twigs) ??
- Rep-PCR can discriminate PSM race 1 from PSM race 2
- Diagnosis: difficult to find out a specific primer
- Which is the role of spring frost ??
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MANY THANKS FOR YOUR KIND ATTENTION !!!
For further pictures:
www.atlasplantpathogenicbacteria.it