Genome-wide identification of wheat Ubiquitin-conjugating enzyme gene family and its role in wheat powdery mildew disease resistance

Ubiquitin-conjugating enzyme (UBC) E2 is a critical component of the ubiquitination process. It interacts with the RING domain of E3 ligases through its UBC domain, enables specific identification of substrate proteins, thereby plays a pivotal role in plant growth and development. In this study, the number, gene structure, and evolutionary relationships of UBC genes in wheat and Arabidopsis thaliana were analyzed at a whole-genome level. Furthermore, the roles of TaUBC genes in wheat resistance to powdery mildew were investigated. A total of 180 UBC genes were identified in wheat and categorized into 15 Classes through phylogenetic analysis. Quantitative real-time PCR analysis revealed significant expression changes of TaUBC1A-5, TaUBC1A-6, TaUBC3A-5, TaUBC3B-14, TaUBC5A-2, TaUBC6A-2, and TaUBC7A-2 after the powdery mildew infection, compared to the 0-h time point. Virus-induced gene silencing experiments demonstrated that TaUBC3A-5 positively regulates wheat resistance to powdery mildew, whereas TaUBC3B-14 acts as a negative regulator. These findings provide valuable insights into the function of the UBC gene family in wheat and offer support for development of new disease-resistant wheat germplasm using UBC genes.