Elucidating the structural basis of effector induced susceptibility in the Parastagonospora nodorum - wheat interaction
M. OUTRAM (1), X. Zhao (1), S. Breen (2), P. Solomon (2), B. Kobe (1), S. Williams (2) (1) University of Queensland, Australia; (2) The Australian National University, Australia

Parastagonospora nodorum, the causal agent of Septoria Nodorum Blotch, is a major necrotrophic fungal pathogen of wheat worldwide. P. nodorum secretes small cysteine-rich proteinaceous effectors (ToxA, Tox1 and Tox3) that interact with corresponding dominant host sensitivity gene products, promoting cell death and rendering the plant susceptible to disease. Whilst it is now understood that these effectors are required for disease, there is little understanding of their function. Recently Tox3 from P. nodorum has been shown by yeast two-hybrid and co-immunoprecipitation assays to interact with basic and acidic wheat pathogenesis-related 1 (PR1) proteins. We have developed a protein expression and purification system that produces Tox3 and wheat PR1 proteins. The recombinant Tox3 protein was determined to be functional based on wheat infiltration experiments. We present here the in-solution biophysical characterisation of Tox3 and wheat PR1 proteins using multi-angle light scattering coupled with size-exclusion chromatography. We further present the first crystal structure of an acidic wheat PR1 protein. This data provides structural and mechanistic insights into the interaction between Tox3 and wheat PR1 proteins.

Abstract Number: P17-580
Session Type: Poster