Late blight pathogen targets host Rab-G3 GTPases with an atypical GTPase-activating protein.

ABSTRACT: Late blight pathogen Phytophthora infestans secretes numerous effectors to suppress plant immunity. However, little is known about their underlying biochemical mechanisms. Here we report that, in the host Nicotiana benthamiana, P. infestans core RXLR effector Pi17063 suppresses plant immunity by targeting the host plasma membrane and NbRab-G3 proteins, small GTPases of the Ras-related brain (Rab) family. Pi17063 functions as their specific GTPase-activating protein (GAP), driving them to the cytoplasm-localized guanosine diphosphate (GDP)-bound inactive state. Mutant analysis of the conserved Pi17063 arginine residues showed the essential role of its GAP activity for virulence contribution. All four NbRab-G3 subfamily members are positive immune regulators, and NbRab-G3c mutants lost the a

SUBMITTER: Liu S 

PROVIDER: S-EPMC12315501 | biostudies-literature | 2025 Aug

REPOSITORIES: biostudies-literature