Identification, Characterization and Expression Profiling of the RS Gene Family during the Withering Process of White Tea in the Tea Plant ( Camellia sinensis ) Reveal the Transcriptional Regulation of CsRS8 .

Raffinose synthetase (RS) is a key enzyme in the process of raffinose (Raf) synthesis and is involved in plant development and stress responses through regulating Raf content. As a sweetener, Raf makes an important contribution to the sweet taste of white tea. However, studies on the identification, analysis and transcriptional regulation of ( RS genes) are still lacking. In this study, nine CsRSs were identified from the tea plant () genome database. The CsRSs were classified into five groups in the phylogenetic tree. Expression level analysis showed that the varied in different parts of the tea plant. Transcriptome data showed that could respond to persistent drought and cold acclimation. Except for and , the expression pattern of all increased at 12 h and decreased at 30 h during the withering process of white tea, consistent with the change trend of the Raf content. Furthermore, combining yeast one-hybrid assays with expression analysis, we found that CsDBB could potentially regulate the expression of . Our results provide a new perspective for further research into the characterization of genes and the formation of the white tea flavour.