The GEMO project: Hitchhiking DNA in Magnaporthe oryzae

Abstract

National audienceMagnaporthe oryzae is a successful pathogen of crop plants and a threat for food production worldwide. This species gathers pathogens of different Poaceae including rice and wheat and causes the main fungal disease of rice worldwide. The Evolutionary Genomics of Magnaporthe oryzae (GEMO) project is an attempt to identify the genomic determinants and evolutionary events involved in pathogenesis, host specificity and adaptation. We have analyzed and compared a dataset of ten closely related genomes of the Magnaporthe oryzae/grisea species complex selected for their different main host and host range. We put emphasis on the horizontally acquired material that we predicted with a parametric detection method based on tetranucleotide signature. We outline the general content of the predicted transferred regions and propose for some candidates the likely taxonomy of their potential donors. We depicted and compared the functional profiles of the host and acquired genes and investigated the intermingling of horizontal transfers with our de novo prediction of transposable elements as a potential adaptative and evolutionary feed. First results pointed out a few large transferred regions potentially acquired from distant species identified by alignment-free methods, including several plant-pathogen fungi. These candidates called for further research around their potential contribution to phenotype, in a step to open the general study of the yet unresolved evolutionary tangram of the Magnaporthe oryzae pathogenesis