Systematic analysis of potato MYB family genes and their potential functions in anthocyanin biosynthesis

MYB proteins, one of the largest transcription factor superfamilies in plant kingdom, play essential roles in plant development and metabolic regulation, including anthocyanin biosynthesis. MYB family genes have been widely identified in many plant species, but which have not yet been comprehensively identified and systematically analyzed in the latest potato genome (DM v6.1, the PGSC 2020). In this study, a total of 294 StMYB genes were identified, including 149 St1R-MYBs, 142 St2R-MYBs, and three St3R-MYBs. The 142 St2R-MYB proteins were classified into 20 subgroups, and similar protein motifs were found within the same subgroup. A total of 12 candidate St2R-MYB genes were screened out by phylogenetic clustering analysis for regulating anthocyanin biosynthesis. Among them, four genes StMYB_66, StMYB_99, StMYB_150 and StMYB_248 had negative regulatory functions, while the functions of four genes StMYB_240, StMYB_241, StMYB_242 and StMYB_243 were opposite in anthocyanin biosynthesis through tobacco transient transformation. These results laid the foundation for further study on biological functions and molecular mechanisms of the St2R-MYB genes regulating anthocyanin biosynthesis in potato, and provided theoretical basis and new gene resources for the breeding of colorful potato varieties.