Genome-Wide Analysis of the R2R3 MYB Subfamily Genes in Lotus (Nelumbo nucifera)

MYB superfamily is one of the most abundant transcription factors in plants, which are involved in many physiological and biochemical processes. Among them, R2R3 MYB might be the most widely studied subfamily. Here, we characterized the gene structures, expressional patterns, and potential functions of 116 R2R3 MYB genes in a genome-wide manner in lotus (Nelumbo nucifera). Compared with those in Arabidopsis and grape, the lotus R2R3 MYB genes are conserved in exon's number and length. Most of them constitute three exons and two introns with the first two exons being highly conserved in their length. According to the structure of exon and DNA-binding domain-imperfect repeat (R), these R2R3 MYB genes were classified into four groups. The expression of 13 candidate MYB genes that are related to flavonoid biosynthesis was analyzed in lotus different tissues. One gene expresses highly in all tissues and might positively regulate common flavonoid biosynthesis. Two genes might positively regulate anthocyanin and proanthocyanidin biosynthesis, respectively, resulting in the pigmentation of flower and seed. While five members that are similar to Zm38 are expressed lowly in different tissues. This genome-wide analysis of R2R3 MYB genes in lotus may provide more comprehensive insights on the structure and function of this gene family, and hence contribute a lot to plant's genetic engineering in improving the colorization of flowers or other tissues.