Genome-wide identification and characterization of R2R3-MYB transcription factors in pear

The R2R3-MYB proteins comprise the largest diverse family of transcription factors in plants and regulate development and secondary metabolism. Although R2R3-MYB TFs have been investigated in some plant species, no systematic analysis has been conducted in pear. This study identified 184 R2R3-MYB TFs in the pear (Pyrus bretschneideri Rehd.) genome. A comprehensive analysis of this gene family was performed, including phylogeny, gene structure, gene duplication, and conserved motifs. Phylogenetic analysis indicated that 184R2R3MYB TFs can be divided into 34 subgroups. Evolutionary relationships within subgroups were supported by exon/intron structures. The phylogenomic comparison of R2R3-MYB proteinsamong pear, apple and Arabidopsis suggested that most of R2R3-MYB members have strong conserved roles, whereas others might exhibit particular functions. Seven anthocyain-related R2R3-MYB TFs were identified and their expression profiles were also analyzed in different tissues. The function of an anthocyanin R2R3-MYB TF, PyMYB70 was further verified by experimental confirmation. Our findings represent the first step towards understanding the functions of R2R3-MYB transcription factors in pear.