The Characterization of R2R3-MYB Genes in Water Lily Nymphaea colorata Reveals the Involvement of NcMYB25 in Regulating Anthocyanin Synthesis

<i>Nymphaea colorata</i>, valued for its diverse flower colors and attractive shapes, is a popular ornamental aquatic plant. Anthocyanins provide color to flowers, and their biosynthesis is regulated by the R2R3-MYB transcription factor. In this study, we identified and analyzed the R2R3-MYB genes in <i>N. colorata</i>, focusing on their structure, evolution, expression patterns, regulatory mechanisms, and biological functions. We also investigated the role of the <i>NcMYB25</i> gene in anthocyanin biosynthesis. There were 59 R2R3-MYB genes in <i>N. colorata</i>, distributed across 14 chromosomes. Among these, 14 genes were involved in segmental duplications and 6 in tandem duplications. Multiple R2R3-MYB transcription factors appeared to play a role in biological processes in <i>N. colorata</i>, including NcMYB48 in flavonoid synthesis, NcMYB33 in lignin synthesis, NcMYB23 in cold stress response, and NcMYB54 in osmotic stress response. Additionally, we identified 92 miRNAs in <i>N. colorata</i>, with 43 interacting with 35 R2R3-MYB genes. The NcMYB25 protein is localized in the nucleus and possesses transcriptional activation activity. Overexpression of the <i>NcMYB25</i> gene in an apple pericarp resulted in anthocyanin accumulation. These findings provide insight into the evolutionary trajectory of the R2R3-MYB genes in <i>N. colorata</i> and highlight the regulatory function of the <i>NcMYB25</i> gene in anthocyanin biosynthesis.