Abstract
CSN5 is one of the subunits of the COP9 signalosome, which can regulate plant life activities by participating in the ubiquitination process. It is also positively correlated with JA signal intensity in plants and regulates JA-dependent plant defense responses. In this study, a total of three CSN5 family genes were identified in tomatoes and a systematic bioinformatics analysis was performed to clarify their similarities and differences. In addition, by analyzing the publicly available transcriptome data and qRT-PCR experiments, it was found that SlCSN5-2 and SlCSN5-3 were up-regulated under gray mold disease stress, and the potential key gene SlCSN5-3 was up-regulated most significantly. Silencing SlCSN5-3 in tomatoes resulted in reduced resistance to gray mold disease, and it was clear that SlCSN5-3 positively regulates tomatoes' resistance to gray mold disease through the JA pathway.