Genome-wide identification and characterization of the R2R3MYB transcription factor superfamily in eggplant (Solanum melongena L.)

The R2R3MYB proteins comprise one of the largest families of transcription factors and play regulatory roles in developmental processes and defense responses in plants. However, limited comprehensive genomic and functional analyses of these genes in eggplant (Solanum melongena L.) have been performed. In this study, 73 R2R3MYB genes were identified in the recently released eggplant genome and further classified into 20 subgroups based on the phylogenetic analysis of their complete protein sequences. Phylogenetic comparisons of this superfamily’s members among eggplant, tomato, Arabidopsis, grape, rice, poplar, soybean, cucumber and apple revealed that the putative functions of some of the eggplant R2R3MYB proteins were clustered into the Arabidopsis functional clades. The tissue specificity or differential expression of SmR2R3MYBs in different tissues suggested the differential regulation of tissue development as well as metabolism. The transcript abundance analysis under abiotic stress identified a group of R2R3MYB genes that responded to one or more treatments, suggesting that SmR2R3MYBs played major roles in the plants response to abiotic stress and were involved in signal transduction pathways. Genes related to anthocyanin synthesis were also identified. This study not only provides a solid foundation for the functional dissection of the eggplant R2R3MYB gene family, but may also be useful for the future synthesis of anthocyanins in eggplant.