LAUSR

Puccinia graminis f. sp. tritici, the causative agent of wheat stem rust, uses various effectors to infect its plant host. However, host recognition of effectors and the subsequent immune responses can provide resistance to infection and, in response, the fungal pathogen modifies its effectors. Two new studies now identify such effectors that are crucial targets of plant immune responses. Salcedo et al. compared whole-genome sequences of natural and mutagenized fungal strains to identify AvrSr35, which interacts with the Sr35 immune receptor. Insertion of a mobile element into and inactivation of the effector gene was associated with evasion of plant resistance. Chen et al. identified the AvrSr50 effector in a spontaneous virulent mutant that was able to overcome Sr50-dependent resistance. Identification of these two effectors will help with surveillance for the emergence of resistant wheat stem rust variants and the development of new strategies to provide plant resistance.