Graduate Student University of California, Riverside RIVERSIDE, California
Body of Abstract: Effectors, small, secreted proteins which modulate plant immune response, are critical for successful fungal infection. While the effector proteins of biotrophic and hemibiotrophic fungi have been well characterized, little research has been done on the effector proteins of necrotrophic fungal plant pathogens. Beginning in 2016, research on necrotrophic fungal effectors began to illuminate the vast collection of effector proteins found in the genomes of necrotrophic fungi. Many of these predicted effectors lack a N-terminal signal peptide targeting them for the traditional secretion pathway, so it remains unclear how these effectors are delivered to the apoplastic space, and subsequently, plant cells. Recent discoveries have shown that Arabidopsis thaliana utilizes extracellular vesicles (EVs) to deliver sRNAs to its fungal pathogen, Botrytis cinerea. This exchange of EVs is potentially bidirectional, with fungal EVs packaging and delivering fungal effectors into plant cells. In fact, EVs have been shown to transport the effectors of human fungal pathogens into human cells, though no such research has been done on necrotrophic fungal plant pathogens. With this in mind, our goal is to examine the EVs of Botrytis cinerea to determine if they are trafficking effector proteins. We have identified potential effector proteins and through the generation of mutant B. cinerea strains with the effectors knocked out or tagged with YFP we will determine the transport mechanism of the identified effectors. Preliminary data has indicated that our chosen proteins are in fact effector proteins, as the deletion mutants show a decreased ability to infect and kill A. thaliana cells. Our research will greatly expand the understanding of the roles of extracellular vesicles in fungal pathogenesis as well as identify a non-conventional secretion pathway of protein effectors.