Characterization of the R2R3-MYB Transcription Factor CsMYB113 Regulates Anthocyanin Biosynthesis in Tea Plants (Camellia sinensis)

Tea plant (Camellia sinensis) has very long history of cultivation and abundant germplasm resources in China. Purple bud is a characteristic variety, which has attracted the attention of breeding researchers because it accumulated a large number of anthocyanins naturally. In many species, R2R3-MYB transcription factors (TFs) were proved to be involved in the regulation of anthocyanin biosynthesis. Research on anthocyanin metabolism has been relatively clear in some species, but that needs to be further elucidated in tea plants. In this research, an R2R3-MYB transcription factor CsMYB113 related to the anthocyanin accumulation regulation was identified from tea plants. Spatial and temporal expression analysis revealed differential expression of CsMYB113 among different tissues and organs, with highest expression occurring in the roots. Subcellular localization assays showed that CsMYB113 localized in the nucleus. Ectopic expression of CsMYB113 increased pigmentation and anthocyanin contents by the upregulation of the expression levels of genes in anthocyanin biosynthesis pathway among different tissues of Arabidopsis. Moreover, transient overexpression of 35S::CsMYB113 in tea plant increased the anthocyanin contents in the leaves. Our results indicated that CsMYB113 plays important role in the anthocyanin biosynthesis regulation in tea plants. It will also provide useful candidate gene for the modification of anthocyanin metabolism by genetic engineering in plants.