Partenaires et organisations internationales
(Anglais)
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A, B, BG, DK, FIN, F, D, GR, H, IRL, I, LT, N, PL, P, SI, E, S, CH, GB
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Résumé des résultats (Abstract)
(Anglais)
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This research is focused on the interaction between poplar and xanthomonas populi pv. populi (xpp). This bacterium causes oozing canker on the trunk and leads to important economic losses. The physiology and epidemiology of poplar canker is well characterized but little is known at the molecular level. The goal of this phd project is to identify and characterize the bacterial virulence genes and their target(s) in the host. So far, we have characterized a series of different virulent strains of xpp (cfbp strains : 1817, 1925, 2694 and 2112). This includes pcr-fingerprinting, genomic organization analysis by pfge and transformation tests. We are now studying the responses of different natural hosts (p. trichocarpa x p. euramerica inra clone 717-1b4 ; p. trichocarpa x p. deltoides ; p. maximorwizii x p. deltoides) and non-host plants (nicotiana tabacum and arabidopsis thaliana) to virulent and avirulent xpp strains. We have developed a reliable foliar test on the common clone 717-1b4 that shows a clear response of the host corresponding to the virulence of the bacteria. the response (compatible or incompatible) of the non-host plants is under characterization. To identify virulence genes of xpp, we have used a cloning strategy based on sequence homology with genes in the xanthomonas genus. So far, we have already cloned 4 putative virulence genes (hpag, hpaa, hpab, avrbs2). these genes will now be used for transient/stable transformation of host or non-host plants and their effect on the pathogenicity of xpp will be determined. future steps will include a characterization of the molecular interaction of the virulence gene product with host cell components.
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