Résumé
GEMO is a project of comparative fungal genomics focusing on related species and sub-species from the Magnaporthe grisea/oryzae species complex. The dataset gathered by the GEMO project encompasses 10 Magnaporthe genomes: 9 M. oryzae genomes from isolates specifically pathogenic on Oryza sativa, Triticum sp, Setaria sp or Eleusine sp, and 1 from a M. grisea isolate specifically pathogenic on Digitaria sp. In this project, the MIG in collaboration with the URGI-Bioger platform are realizing a comparative analysis of these genomes which consists of automatic annotation of genes, structural comparison of these genomes and detection of positive selection in orthologs across this taxonomic sampling [1]. In addition, a detailed evolutionary and syntenic analysis will be performed on two particular groups of genes encoding putative effectors known to be involved in pathogenicity: small secreted proteins (SSPs) and genes involved in the biosynthesis of secondary metabolites. The first step will be to establish the repertory of genes belonging to these families in the 10 available genomes. Different sources of information will be used, such as a set of lists of secondary metabolism genes already established [1], a list of SSP to be compiled fromdifferent sources (transcriptomes, proteomes, effectomes), the automatic annotations of the 10available genomes, and RNAseq data from in planta early infection. We will then address three questions: 1) Are SSP and secondary metabolism genes more subject to birth/death/duplication processes and to horizontal gene transfers, than the rest of the coding genome? 2) Are transposable elements more frequently associated with SSP and secondarymetabolism genes than in the rest of the coding genome? 3) Are SSP and secondary metabolism genes more targeted by positive selection than the rest of the coding genome? All this information will allow depicting the evolutionary history of some pathogenicity and host-specificity related genes in Magnaporthe. [1] Collemare 2007. Communication entre les plantes et leurs agents pathogènes : rôle des métabolites secondaires dans la reconnaissance du champignon Magnaporthe grisea par le riz. PhD Thesis.