Dissecting the Genome-Wide Evolution and Function of R2R3-MYB Transcription Factor Family in Rosa chinensis

Abstract

<i>Rosa chinensis</i>, an important ancestor species of <i>Rosa hybrida</i>, the most popular ornamental plant species worldwide, produces flowers with diverse colors and fragrances. The R2R3-MYB transcription factor family controls a wide variety of plant-specific metabolic processes, especially phenylpropanoid metabolism. Despite their importance for the ornamental value of flowers, the evolution of <i>R2R3-MYB</i> genes in plants has not been comprehensively characterized. In this study, 121 predicted <i>R2R3-MYB</i> gene sequences were identified in the rose genome. Additionally, a phylogenomic synteny network (synnet) was applied for the <i>R2R3-MYB</i> gene families in 35 complete plant genomes. We also analyzed the <i>R2R3-MYB</i> genes regarding their genomic locations, Ka/Ks ratio, encoded conserved motifs, and spatiotemporal expression. Our results indicated that <i>R2R3-MYBs</i> have multiple synteny clusters. The <i>RcMYB114a</i> gene was included in the Rosaceae-specific Cluster 54, with independent evolutionary patterns. On the basis of these results and an analysis of <i>RcMYB114a</i>-overexpressing tobacco leaf samples, we predicted that <i>RcMYB114a</i> functions in the phenylpropanoid pathway. We clarified the relationship between <i>R2R3-MYB</i> gene evolution and function from a new perspective. Our study data may be relevant for elucidating the regulation of floral metabolism in roses at the transcript level.