Identification of R2R3-MYB family in blueberry and its potential involvement of anthocyanin biosynthesis in fruits.

ABSTRACT

BACKGROUND: Blueberries (Vaccinium corymbosum) are regarded as "superfoods" attributed to large amounts of anthocyanins, a group of flavonoid metabolites, which provide pigmentation in plant and beneficial effects for human health. MYB transcription factor is one of vital components in the regulation of plant secondary metabolism, which occupies a dominant position in the regulatory network of anthocyanin biosynthesis. However, the role of MYB family in blueberry responding to anthocyanin biosynthesis remains elusive. RESULTS: In this study, we conducted a comprehensive analysis of VcMYBs in blueberry based on the genome data, including phylogenetic relationship, conserved motifs, identification of differentially expressed MYB genes during fruit development and their expression profiling, etc. A total of 437 unique MYB sequences with two SANT domains were identified in blueberry, which were divided into 3 phylogenetic trees. Noticeably, there are many trigenic and tetragenic VcMYBs pairs with more than 95% identity to each other. Meanwhile, the transcript accumulations of VcMYBs were surveyed underlying blueberry fruit development, and they showed diverse expression patterns, suggesting various functional roles in fruit ripening. More importantly, distinct transcript profiles between skin and pulp of ripe fruit were observed for several VcMYBs, such as VcMYB437, implying the potential roles in anthocyanin biosynthesis. CONCLUSIONS: Totally, 437 VcMYBs were identified and characterized. Subsequently, their transcriptional patterns were explored during fruit development and fruit tissues (skin and pulp) closely related to anthocyanin biosynthesis. These genome-wide data and findings will contribute to demonstrating the functional roles of VcMYBs and their regulatory mechanisms for anthocyanins production and accumulation in blueberry in the future study.