PS Webinar Series: The crystal structure of SnTox3 from the necrotrophic fungus Parastagonospora nodorum reveals a unique effector fold and insights into Kex2 protease processing of fungal effectors

Abstract - Plant pathogens cause disease through secreted effector proteins, which act to modulate host physiology and promote infection. Often, effector proteins lack sequence identity to proteins of known function, or functional domains, making it impossible to infer function based on sequence alone. To unravel effector function we utilise structural biology and protein biochemistry techniques, which are often reliant on high yields of protein. In this talk, I will report our experiences expressing the cysteine-rich effector SnTox3 from Parastagonospora nodorum, the causal agent of Septoria nodorum blotch on wheat, which culminated in the structure determination of SnTox3 using X-ray crystallography. I will also present our successes utilising this approach for other effectors from pathogenic fungi, and present data that supports the definition of a new subclass of fungal effectors as well as the implications this has for how we study fungal effectors.

Biography - Megan was awarded her PhD in structural biology and protein biochemistry from the University of Queensland (Brisbane, Australia) in August 2019. She carried out her doctoral studies in the laboratory of Prof. Bostjan Kobe (School of Chemistry and Molecular Biosciences), in collaboration with Dr. Simon Williams and Prof. Peter Solomon in the Research School of Biology at the Australian National University (Canberra, Australia). In March 2019, Megan moved to The Australian National University to work in the newly established plant structural immunology laboratory lead by Dr. Simon Williams. Megan’s current research focuses on using structural biology and protein biochemistry techniques to understand effector function as well as effector recognition and activation of plant innate immune receptor proteins in a variety of plant-pathogen interactions.