Skip to main content
ISMPMI Congress 2025 Main banner
Icon Legend
This session is not in your schedule.
This session is in your schedule. Click again to remove it.

Poster

Session: Session 1 Presenting Authors at Posters (Evens)

P-052 - Lettuce as a model euasterid II plant for new insights into the functions of the composite bacterial effector AvrRps4

Tuesday, July 15, 2025
09:55 - 11:30  
Location: Confex Hall 3
Extracellular & Intracellular non-self recognition & signaling

This study focuses on the bacterial effector AvrRps4 from the pea pathogen Pseudomonas syringae pv. pisi. Effectors of the AvrRps4 family are processed after delivery into plant cells, and in Arabidopsis both AvrRps4 moieties are required to trigger resistance mediated by the resistance protein pair RPS4/RRS1. The function of the AvrRps4 C-terminus (AvrRps4-C) and its interaction with RRS1 and WRKY transcription factors is well understood. In contrast, little is known about the function of the N-terminal moiety (AvrRps4-N) that is associated with at least two distinct C-termini, AvrRps4-C and HopK1-C. We and collaborators demonstrated that transient expression of AvrRps4-N and XopO-N in Lactuca sativa (lettuce) generates a strong hypersensitive response (HR). In addition, the AvrRps4-N-triggered HR is weakened by co-expression of AvrRps4-C, perhaps explaining why a fusion of these two proteins was retained through evolution. We propose that studying AvrRps4 family effector interactions with lettuce will allow us to dissect AvrRps4-N triggered resistance signaling and to discover host targets of AvrRps4-N that determine disease or resistance. We will provide updates on developing LsEDS1 knock-out lines and a Xanthomonas hortorum pv. vitians strain for disease assays in lettuce. Funded by USDA NIFA PBI 2022-11933 (WG, JS, BY).