Identification of genetic bases of male fertility in Pyricularia oryzae by Genome Wide Association Study (GWAS).

Abstract

The reproductive system of an organism impacts the emergence and evolution of adaptive variants in response to selective constraints. The understanding of the sexual mode of reproduction in pathogens helps to understand their life history. In filamentous Ascomycete fungi, mating type system and the production of gametes are required to reproduce sexually. In the phytopathogenic Ascomycete Pyricularia oryzae, studies of the genetic determinants of sexual reproduction are still limited to the mating type system. This study focuses on identifying the genes involved in male fertility through the production of male gametes known as microconidia. We performed a GWAS analysis coupled with a local score approach on a wild recombinant population of Pyricularia oryzae phenotyped for microconidia production. We identified one genomic region significantly associated with the quantity of microconidia produced. This region contained nine candidate genes, some of them annotated with functions associated to sexual reproduction in model fungi such as Neurospora crassa, Podospora anserina and Sordaria macrospora. The most promising candidate gene contains a Jumonji domain. Proteins belonging to the Jumonji family are conserved among Eukaryotes and are known to be involved in chromatin regulation.