The RING-Type E3 Ubiquitin Ligase Gene Negatively Regulates Resistance in Cotton ().

Cotton is one of the world's most important economic crops. Verticillium wilt is a devastating cotton disease caused by , significantly impacting cotton yield and quality. E3 ubiquitin ligases are essential components of the ubiquitin-mediated 26S proteasome system, responsible for recognizing ubiquitinated target proteins and promoting their degradation, which play a crucial regulatory role in plant immune responses. In this study, on the basis of the confirmation of differential expression of , a RING-type E3 ubiquitin ligase encoding gene, in two cotton varieties resistant (Zhongzhimian 2) or susceptible (Jimian 11) to , we demonstrated that is a negative regulator of resistance because silencing in cotton and heterogeneously overexpressing the gene in Arabidopsis enhanced and compromised resistance to , respectively. The -mediated immune response seemed to be realized through multiple physiological pathways, including hormone signaling, reactive oxygen species, and lignin biosynthesis. Based on the sequences of isolated from Zhongzhimian 2 and Jimian 11, we found that had identical coding but different promoter sequences in the two varieties, with the promoter of Zhongzhimian 2 being more active than that of Jimian 11 because the former drove a stronger expression of GUS and LUC reporter genes. The results link the ubiquitination pathway to multiple physiological pathways acting in the cotton immune response and provide a candidate gene for breeding cotton varieties resistant to .