The ubiquitin-proteasome system (UPS) is an important mechanism that plants use to regulate protein tuover for growth,development,and responses to abiotic and biotic stresses.Among the three main kinds of UPS enzymes,E3 ubiquitin ligases (E3s) are highly flexible and diverse,and each has unique specificity in recognizing substrates.Many studies have indicated that E3s play pivotal roles during plant-pathogen interactions (Duplan and Rivas,2014).