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Poster

Session: Session 2 Presenting Authors at Posters (Odds)

P-101 - A Pathogen Effector Manipulates a Host Susceptibility Factor to Restructure the Pathogen Interface and Inhibit Defense-Associated Secretion

Wednesday, July 16, 2025
13:30 - 15:15  
Location: Confex Hall 3
Effector Interference Mechanisms
Pathogens have developed intricate strategies to manipulate host cell membrane dynamics, an essential adaptation for survival in environments shaped by innate immune defenses. In plants, membrane structures that envelop invasive hyphal projections of fungal and oomycete pathogens serve as critical sites influencing infection outcomes. Understanding how pathogens transform these host-pathogen interfaces to their advantage remains a key biological question. Here, we identified a conserved effector, secreted by plant pathogenic oomycetes, that co-opts a host Rab GTPase-activating protein (RabGAP), TOPGAP, to remodel the host-pathogen interface. The effector, PiE354, hijacks TOPGAP as a susceptibility factor to usurp its GAP activity on Rab8a, a key Rab GTPase crucial for defense-related secretion. By hijacking TOPGAP, PiE354 purges Rab8a from the plasma membrane, diverting Rab8a-mediated immune trafficking away from the pathogen interface. This mechanism signifies an uncanny evolutionary adaptation of a pathogen effector in co-opting a host regulatory component to subvert defense-related secretion, thereby providing unprecedented mechanistic insights into the reprogramming of host membrane dynamics by pathogens.