Professor University of Neuchâtel Neuchatel, SWITZERLAND
Plant-fungal interactions are characterized by evolutionary arms races, where fungal effectors target important plant functions and plants in turn evolve to recognize effectors. Crops may suffer breakdowns in effective resistance caused by pathogen evolution faster than new resistance can be deployed. Recent work showed that rapid evolutionary change in effector proteins was facilitated by transposable elements (TEs). High TE activity is hypothesized to contribute to faster effector evolution. Determining mechanisms of recent effector evolution could help predict resistance durability, however few studies addressed such questions at species and genome-wide scales. Here, we take a comparative genomics and species-wide approach to define TE dynamics at effector gene loci across two major pathosystems. In the fungal wheat pathogen Zymoseptoria tritici, we analyzed a 1000-genome panel and identified fast TE content turnovers near the major effector gene AvrStb6 causing losses and chromosomal rearrangements. Across host-specific lineages of Magnaporthe oryzae, we revealed TE insertion dynamics most likely underpinning the observed translocations, duplications and losses of effector genes. The recent diversification of M. oryzae lineages and ongoing gene flow produced significant shared TE polymorphisms among lineages. Our work demonstrates how TE dynamics are an integral component of pathogen effector evolution and need to inform resistance management.
