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Characterisation of major Ralstonia solanacearum type III pathogenicity Determinants

Final Activity Report Summary - CHARADE (CHaracterisation of major RAlstonia solanacearum type III pathogenicity DEterminants)

Most pathogenic bacteria are endowed with a Type III secretion system (TTSS) that directly translocates bacterial proteins into the host cell cytoplasm. Besides its inherent interest as a paradigmatic example of information transfer between bacteria and eukaryotes, the TTSS has been shown to be a major pathogenicity determinant. Thus, the study of bacterial effector proteins injected through the TTSS to promote disease is a question hic et nunc in plant and animal pathogenicity.

This study was oriented towards a better understanding of the awr effector gene family, found in the plant pathogen R. solanacearum, whose members exhibit no similarities in the databases. The work carried out in this project included a systematic functional analysis of the awr genes and their protein products. An intriguing cell death phenotype has been observed when the genes are transiently expressed inside plant cells and some of their plant targets have been identified. Experiments are under way to unveil the exact mechanisms through which these bacterial proteins contribute to the development of plants wilting symptoms.

Outcomes of this work include several presentations in workshops and congresses (two poster presentations) as well as the training of two undergraduate students and a PhD student. The interesting scientific results enable us to envision, as foreseen, the publication of an original research article in a high or medium-impact journal at the end of the second year of the project.