Posttranslational Modifications in Plant Disease Resistance

Abstract Under constant attack from an ever‐evolving array of pathogens, the multilayered plant immune system provides a broad‐spectrum resistance that is the result of millions of years of coevolution of plants and microorganisms. Driving the arms race for survival is the continual diversification of defence and attack mechanisms. This process can be rapidly and efficiently achieved by posttranslational modifications (PTMs). Phosphorylation and ubiquitination are important PTMs involved in plant immune signalling that are exploited by pathogens and plants alike. Identified connections between the two PTMs have been shown to either positively or negatively regulate each other, affecting the activity of a growing number of immune proteins. In various instances, this crosstalk has been shown to link the two alleged levels of innate plant immunity: PAMP‐triggered immunity (PTI) and effector‐triggered immunity (ETI). Understanding how this occurs will lead us to unravel the web that is the plant immune signalling interactome. Key Concepts Natural selection drives the diversification of pathogen virulence and plant resistance mechanisms. Posttranslational modifications are essential for providing rapid and efficient diversification of defence and attack proteins. Phosphorylation and ubiquitination are important posttranslational modifications involved in plant immune signalling. Crosstalk between ubiquitination and phosphorylation regulates plant immune signalling. Crosstalk between ubiquitination and phosphorylation can link different levels of the plant immune system.