Specific Task Force COST 873

Determination of the Incidence of the Different Pathovars of Pseudomonas syringae in Stone Fruits

Interested countries: Belgium

Czech Republic

Germany

Hungary

Latvia

Lithuania

Poland

Slovenia

The Netherlands

Turkey

UK

1. The situation

RIPF Skierniewice

The bacterial canker of sweet cherry (Prunus avium)

Naturally induced symptoms from which the pathogens were isolated were:

Pseudomonas syringae pv. syringae : - Fruit spots - Leaf spots- Dead buds with limited progression in the branch- Blossom blast with limited progression in the branch- Only one report (France) of high progression in branches

Pseudomonas syringae pv. morsprunorum race 1- Fruit spots - Leaf spots- Dead buds and blossoms with high progression in branches- Infection of branches and trunk with high progression

Pseudomonas syringae pv. morsprunorum race 2- Fruit spots - Leaf spots- Canker (no information about the importance)

Other Pseudomonas syringae or Pseudomonas viridiflava?

The bacterial canker of wild cherry (Prunus avium)

Naturally induced symptoms from which the pathogens were isolated were:

Pseudomonas syringae pv. avii- Infection of branches and trunk with high progression

Pseudomonas syringae pv. syringae- Leaf spots- Cankers on branches and trunk (no information about the importance)

Pseudomonas syringae pv. morsprunorum race 1- Leaf spots- Cankers on branches and trunk (no information about the importance)

Pseudomonas syringae pv. morsprunorum race 2- Leaf spots

Other Pseudomonas syringae or Pseudomonas viridiflava?

The bacterial canker of sour cherry (Prunus cerasus)

Naturally induced symptoms from which the pathogens were isolated were:

Pseudomonas syringae pv. syringae- Leaf spots- Fruit spots- Dead buds with limited progression in the branch- Woody tissues (no information about the importance)

Pseudomonas syringae pv. morsprunorum race 1- Leaf spots- Fruit spots- Dead buds with limited progression in the branch

Pseudomonas syringae pv. morsprunorum race 2- Leaf spots- Fruit spots- Dead buds with limited progression in the branch

Other Pseudomonas syringae or Pseudomonas viridiflava?

The bacterial canker of plum

Naturally induced symptoms from which the pathogens were isolated were:

Pseudomonas syringae pv. syringae- Leaf spots- Blossom blast- Dead buds with limited progression in the branch- Only one report (Deutschland) of high progression in branches

Pseudomonas syringae pv. morsprunorum race 1- Leaf spots- Infection of trunk with high progression

Other Pseudomonas syringae or Pseudomonas viridiflava?

In stone fruit orchards, several Pseudomonas syringae pathovars and races can be encountered in a same culture, several organs can be attacked, and the situation is complicated by the presence of epiphytic strains unable to cause disease living on plant surfaces.

Pathogenicity tests performed in artificial conditions are not always a perfect imaging of the real potential of a pathogen in nature. Establish relations existing in Europe between specific disease symptoms observed in the orchards and particular pathogens isolated from the lesions is the main initial objective of the STF.

2. The aim of the STF

The situation in cherry and plum is very complex. Clear information doesn’t exist between the precise symptoms the five known pathogens are really able to induce in nature and about their relative importance in the different cultures (sweet cherry, sour cherry, wild cherry, plum). More information on these points would be useful at several levels: - improve our knowledge on the ecology of these pathogens, - better identify the most damaging organisms on each organ in each

culture, for example in preparation of biological control,- better differentiate and classify these pathogens- allow for selection of correct strain in resistance breeding of stone

fruit cultivars- …

Some complexity also exist in peach

Regrouping information from several European regions would give more value and universality to the results, compared to local data for one region or one country. This kind of work is thus well fitted within the frame of a COST project

3. Progress to date

STF Meeting on “Determination of the incidence of the different pathovars ofPseudomonas syringae in stone fruits”

27th-28th March 2008, Skierniewice, Poland (Organizer: Joanna Pulawska)

BelgiumCzech RepublicHungaryLithuaniaPoland SloveniaThe NetherlandsTurkeyUK

- Only isolate strains from diseased plant material (no leaf washing …) or strains whose origin is sure

- Careful description of the symptom observed:xylem (importance), cortical tissues (importance), dead bud, spots on

leaves, expanding necroses on leaves, blossom blight (base of the pedicel), flower necrosis (problem in the flower and sepals), necroses on fruits (type of necrosis)

- Strains named according to generally accepted methods of identification- LOPAT- GATTa tests- Pyoverdin-based identification tests- PCR cfl for coronatine production- PCR syrB and syrD + biological test for syringomycins and syringopeptins production- PCR irp1 (PSYE2-PSYE2R primers) for yersiniabactin production- Rep-PCR for stone fruit Pseudomonas syringae strains- Others

- Determination of reference strains to use in identification

- Standardization of the presentation of information

Standardisation of work to fulfil the STF objectives

Country Scientist Total Isolates Plant Isolates

Specific research programs

Belgium Alain Bultreys 422 Sweet cherrySour cherryWild cherryPlum

233140346

Poland Joana PulawskaMonika Sulikowska

200 Sweet cherrySour cherryPlumPeach

3395448

Interested scientists without specific funding

Czech Republic Jaroslav Horky 4 PeachSour cherry

31

Hungary Sandor Sule 2 Sweet cherry 2

Lithuania Milda VasinauskieneDaiva Burokiene

~ 10

Turkey Hatice Ozaktan 7 Peach 7

Establishment of collections, present situation

Specific research programs:

Belgium: personal research program of A. Bultreys in the Walloon Agricultural Research Centre in Gembloux, and several past grants (F. Legros, V. Gilbert) from the Walloon Region, Head office of the Agriculture

Poland: National project concerning Pseudomonas and Agrobacterium entitled “Phenotypic and genetic characteristics of bacterial pathogens of stone fruit trees, hazelnut and walnut”; will run up to 2011 (M. Sulikowska, J. Pulawska)

4. Plan for 2009

Continuation of isolations and identifications in different countries

STSMs

STF meeting

Thank you for your attention!