Transcription factor PbbZIP4 is targeted for proteasome-mediated degradation by the ubiquitin ligase PbATL18 to influence pear's resistance to Colletotrichum fructicola by regulating the expression of PbNPR3.

Pear anthracnose caused by Colletotrichum fructicola is one of the main fungal diseases in all pear-producing areas. The degradation of ubiquitinated proteins by the 26S proteasome is a regulatory mechanism of eukaryotes. E3 ubiquitin ligase is substrate specific and is one of the most diversified and abundant enzymes in the regulation mechanism of plant ubiquitination.