USES OF THE <I>PSEUDOMONAS SYRINGAE</I> EFFECTOR PROTEIN HOPU1 RELATED TO ITS ABILITY TO ADP-RIBOSYLATE EUKARYOTIC RNA BINDING PROTEINS

摘要

The bacterial plant pathogen Pseudomonas syringae injects effector proteins into host cells via a type III protein secretion system to cause disease. The invention relates to the discovery that the type III effector HopUl is a mono- ADP- ribosyltransferase (ADP-RT) and suppresses plant innate immunity. The HopU1 substrates in Arabidopsis thaliana extracts were RNA-binding proteins that possess RNA-recognition motifs (RRMs). A. thaliana knock-out lines defective in the glycine-rich RNA-binding protein AtGRP7, a HopU1 substrate, were more susceptible than wild type plants to P. syringae. The ADP-ribosylation of AtGRP7 by HopU1 required two arginines within the RRM. The invention provides novel methods for the modulation of the innate immune response of a plant to a biotic stress, including methods for enhancing or suppressing the innate immune response of the plant.