Genome architecture and virulence gene dynamics in oat crown rust populations

Crown rust caused by Puccinia coronata f. sp. avenae ( Pca ) is the most destructive folia r pathogen of cultivated oat, Avena sativa . Populations of Pca display very high genetic varia bility as demonstrated by the nu merous virulence profiles that can be captured during national and international rust surveys. Such levels of polymorphisms likely confer evolutionar y advantages to the pathogen and drive adaptation to plant resi stance genes deployed in varieties. During the last two decades, Pca populations in the US have undergone drastic virulence shifts yet the underlying genetic and molecular mechanisms responsible for these changes are not understood. Ca pitalizing on the recent release of two genome references for Pca , a comparative population genomics study of two Pca populations collected in 1990 and 2015, respectively, was laun ched. Our goal is to determine the population S1.105 structure and dynamics of Pca , as well as the evolutionary p rocesses that drive virulence ch anges over time, particularly in response to selective pressures and occurrence of sexual reproduction. Overall, this work contributes to the understanding of the biology of Pca and enables the development of molecular markers associated with rust virulence