Résumé
Ralstonia solanacearum is known as an ancestral soil borne plant vascular pathogen that evolved as a highly profiled organism which causes severe damages on a wide range of hosts. Using CGH micro-arrays, Cellier et al. (submitted) questioned the gene content of 72 R. solanacearum strains mainly from phylotype II. This study provide new insights in the evolutionary history of the R. solanacearum complex along with a clear estimation of the gene content of large set of strains. We used the data obtained in this study to first infer a phylogeny before reconstructing gene presence/absence ancestral status along this same phylogeny. We were then able to compute the number of gene gain and loss along lineages. Those results will be presented in regards to (1) recombination between lineages, (2) gene class dynamics and (3) spatial patterns of genome evolution. (Résumé d'auteur)