The Genome-Wide Identification of the R2R3-MYB Gene Family in Chinese Flowering Cabbage and the Characterization of Its Response to Pectobacterium carotovorum Infection

Chinese flowering cabbage is an important bolting stem vegetable widely grown in southern China, but severe losses caused by soft rot disease are very common in this crop. The MYB transcription factor (TF) family is the largest TF family in plants and plays diverse roles in response to stresses. However, the responses of MYB TFs to biotic stress in Chinese flowering cabbage have not been systematically studied. Herein, 255 R2R3-MYB genes were identified in the genome of Chinese flowering cabbage and classified into 29 subgroups based on phylogenetic comparisons with Arabidopsis thaliana. Gene duplication events involved 182 gene duplication pairs, and we found that two tandem duplication events involving R2R3-MYB genes in Chinese flowering cabbage may also affect gene family expansion. Transcriptome data analysis indicated that MYB TF genes are highly enriched in differentially expressed gene (DEG) sets. Combined with phylogenetic and transcriptome analysis, we identified 12 R2R3-MYB genes that potentially play a role in the response to soft rot stress. Our research provides a foundation for further research on the response of R2R3-MYB genes to soft rot stress in Chinese flowering cabbage.