EPIS

The natural resistance of plants to diseases largely relies on a vast number of immune receptors (IRs). These genes exhibit distinctive features: they duplicate at a very high rate, display a particularly significant diversity, and they are organized in complex loci highly variable even among individuals of the same species, which incidentally complicates their annotation and analysis. The central hypothesis of the EPIS project is that this genetic architecture grants the immune system of cultivated plants with a different response ability with respect to the rest of the genome to selective and demographic events. We propose to test this hypothesis within the framework of rice domestication which has caused a substantial loss of genetic diversity with respect to wild forms. The EPIS project will test this hypothesis by studying the impact of domestication and selection on the immunity genes of Asian rice, Oryza sativa, and its wild counterpart, Oryza rufipugon. The specific objectives are (1) to establish a comprehensive inventory of IRs in a representative panel of wild and cultivated rice accessions, (2) to use this rice pan-IRome to elucidate the effects of domestication and selection on IR diversity and study the underlying evolutionary mechanisms, (3) to confront the signatures of selection with the roles of IRs in the immune response to the main fungal pathogen of rice, Pyricularia oryzae. Through these means, the EPIS project will develop new concepts and methods for establishing plant pan-IRomes and produce fundamental knowledge on the evolutionary potential of their immune system. Enhancing the resistance of crops to diseases is a major challenge for future agriculture, aiming to secure food production and reduce the use of phytosanitary products. In this context, EPIS will also generate knowledge directly applicable in crop improvement programs.