Plant Science Innovation, Center for


Date of this Version



Published in final edited form as: Curr Opin Plant Biol. 2008 August ; 11(4): 396–403. doi:10.1016/j.jbi.2008.06.007


Copyright © 2008 Elsevier Ltd.


Phytopathogenic bacteria suppress plant innate immunity and promote pathogenesis by injecting proteins called type III effectors into plant cells using a type III protein secretion system. These type III effectors use at least three major strategies to alter host responses. One strategy is to alter host protein turnover, either by direct cleavage or by modulating ubiquitination and targeting to the 26S proteasome. Another strategy involves alteration of RNA metabolism by transcriptional activation or ADP-ribosylation of RNA-binding proteins. A third major strategy is to inhibit the kinases involved in plant defence signalling, either by removing phosphates or by direct inhibition. The wide array of strategies bacterial pathogens employ to suppress innate immunity suggest that circumvention of innate immunity is critical for bacterial pathogenicity of plants.