Poster Open Access
Magnaporthe oryzaeis a multihost pathogen that infects >50 species of grasses, including the cereal crops wheat, barley and rice. This pathogen deploys an arsenal of secreted proteins called effectors to infect its host plants and counteract plant defences. How M. oryzae effectors have adapted to various grass hosts is poorly understood. Three effectors, AVR-Pia, AVR1-CO39 and AVR-Pik are known to bind sHMA proteins but can also be recognized by NLR resistance proteins with integrated HMA domains. The aim of this project is to discover new M. oryzaeeffectors that interact with sHMA proteins, and determine the diversification of these effectors in host-specific lineages of M. oryzae. First, we predicted candidate effectors from the secretomes of M. oryzaestrains infecting different grass hosts. We used two major criteria: i) proteins with sequence similarity to known avirulence effectors; ii) Hidden Markov Model profile matches to the MAX structural fold. This resulted in 185 potential effector candidates, which we synthesized and cloned as level 0 Golden Gate vectors, and publicly released as a community bioresource. We have been testing these candidates for their ability to interact with sHMA proteins using yeast two-hybrid screens. We have now identified and validated several new effector-HMA interacting pairs. We will build on this work to improve our understanding of the evolution and diversification of HMA-targeting effectors in M. oryzae.