Genetic and pathogenic diversity of Pseudomonas syringae isolates associated with diseases on Belgian fruit trees
(2008)
Files
Gilbert.pdf
Restricted Access - Adobe PDF
- 5.71 MB
Details
- Authors
- Supervisors
- Abstract
- Pseudomonas syringae is divided in more than 50 pathovars. P. syringae pv. morsprunorum (Psm) is reported on stone fruit trees but two races are described and may cause distinct diseases. P. syringae pv. syringae (Pss) is reported, among 180 other hosts, on pear and stone fruit trees; Pss is phenotypically, in pathogenicity, and genetically heterogeneous. Other P. syringae isolates are found on diseased organs. In order to control the disease, a better understanding of the diversity of P. syringae in fruit trees is needed. Genetic characterization of 356 Belgian and 44 foreign P. syringae isolates was done by REP-, ERIC-, BOX- and IS50-PCR. BOX-PCR was useful in identifying Psm race 1 and Psm race 2. The race 2 was found frequently on sour cherry in Belgium. The combination of the four methods was the most discriminative to assess diversity amongst P. syringae and grouped the isolates in distinct genetic populations. Each Psm race 1 and race 2 was relatively homogeneous and genetically distinct from each other. Pss was heterogeneous and its genetic populations from pear, cherry, and plum were distinct from each other. Within cherry trees, homogeneous genetic populations were found on sweet and sour cherry. Interestingly, some genetic populations were more numerous than other ones. However, several genetic populations co-exist on a same host. One hundred and twenty P. syringae isolates were chosen among the different genetic populations and were tested for pathogenicity on different fruit trees organs and on lilac leaf. Psm race 1 and race 2 were mainly pathogenic on cherry twigs but Psm race 1 was more frequently pathogenic on sweet cherry than race 2. Pss isolates aggressive on most (all) organs of all fruit trees tested, were phytotoxin-producing, and isolated from all fruit trees. BOX-PCR was useful in identifying these isolates. On pear, genetic characters and pathogenicity tests highlighted the presence of pear pathogenic P. syringae genetic populations different from phytotoxin-producing Pss populations. The results of this work will make possible to consider the detection of pathogens directly in nurseries and will help researchers involved in disease control, to choose representative isolates of the damaging P. syringae populations on fruit trees.
- Affiliations
Citations
Gilbert, V. (2008). Genetic and pathogenic diversity of Pseudomonas syringae isolates associated with diseases on Belgian fruit trees. https://hdl.handle.net/2078.5/97566