Species from the grass powdery mildew pathogen genus Blumeria infect wild grass and cereal crop plants with high but varying degree of host-specificity. The evolutionary history of the Blumeria species complex is highly dynamic and involves several host-jumps and hybridization events. However, the fungal and plant genes that determine infection success of individual Blumeria lineages on their respective hosts are still unknown and hence the understanding of the evolution of host-specificity remains incomplete.

Additionally, individual isolates of single host-specific Blumeria lineages show race-specific avirulence on distinct host genotypes that contain corresponding resistance (R) genes. The identification and deployment of new R genes represents an important pillar of modern plant resistance breeding. However, the genomic origin of many corresponding fungal avirulence-determining genes is still unknown. Their identification and diversity analysis represent an integral part of pathogen-informed resistance breeding strategies. Moreover, fungal avirulence and virulence genes represent major drivers of pathogen population dynamics both during past and current pathogen evolution. Furthermore, there is growing evidence that R gene mediated resistance also plays an important role in the maintenance of host-specificity barriers.

Therefore, our goal is to identify and study host and pathogen genetic factors that determine the interaction outcome and drive co-evolutionary dynamics between Blumeria lineages and their corresponding hosts. To do so, we use pathogen and host genomics coupled with crossing, phenotypic association studies and gene function analysis.