The role of bacterial phytotoxins in inhibiting the eukaryotic proteasome

• The proteasome is essential for plant defense against pathogens.
• Plant pathogens have exploited the host proteasome to increase their virulence.
• Recent data reveal proteasome inhibition as an alternative virulence strategy.

The ubiquitin-26S proteasome degradation system (UPS) plays a pivotal role in almost all aspects of plant life, including defending against pathogens. Although the proteasome is important for plant immunity, it has been found to be also exploited by pathogens using effectors to increase their virulence. Recent work on the XopJ effector and syringolin A/syrbactins has highlighted host proteasome inhibition as a virulence strategy of pathogens. This review will focus on these recent developments.