Pseudomonas syringae uses the syringe-like Type III Secretion System (T3SS) to inject Type III Secreted Effector (T3SE) proteins into the plant host. The primary role of T3SE proteins is believed to be the suppression of innate immunity. Recognition of effector proteins by the host Resistance (R) proteins results in the initiation of defense responses, including the hypersensitive response (HR). The pathogen can then evolve or acquire new T3SE proteins that evade the host defense response.
Given these dual roles of virulence and defense induction, T3SEs provide excellent tools to probe innate immunity in plants. My lab focuses on identifying new components in innate immunity and understanding their roles in defense, using a wide variety of experimental approaches.