Investigation Of The Role Of The Necrotrophic Effector SnTox1 In Virulence In The Stagonospora nodorum-Wheat Interaction

Stagonospora nodorum is a necrotrophic specialist that has been shown to secrete multiple necrotrophic effectors that are important in disease induction on wheat. These necrotrophic effectors interact directly or indirectly with dominant susceptibility genes in wheat in a genotype specific manner, allowing the pathogen to modulate plant defense mechanisms to its advantage. We have cloned the gene encoding the necrotrophic effector SnTox1 and have recently been investigating the SnTox1-Snn1 interaction. The SnTox1-Snn1 interaction is light dependent and has several hallmarks of a resistance response, however, the interaction results in increased susceptibility rather than resistance. SnTox1 is a small secreted protein with several interesting features including 16 cysteine residues, a lysine rich region, and a region with a high degree of homology to plant chitin binding proteins. Currently we are investigating the mode of action of SnTox1 and have preliminary evidence to show that SnTox1 is not internalized into mesophyll cells but remains in the apoplast during the infection process.