Multi-omics analysis reveals ThMYB6 regulation of flavonoid biosynthesis in differently colored tuberous roots of Tetrastigma hemsleyanum

Feng Yang¹Qiaoyue Xing¹Shouzan Liu¹Yiwen Gu¹Ziyue Wang¹Hongyan Wang¹Qiong Shen¹Shan Li¹Bojie Feng^2*Yan Bai^1*

• ¹Zhejiang Agriculture and Forestry University, Hangzhou, China
• ²General Station of Zhejiang Forestry Extension, Hangzhou, China

Tetrastigma hemsleyanum Diels et Gilg (Vitaceae) is a medicinally valuable plant typically with a whitish root cross-section. Resource surveys discovered some roots of T. hemsleyanum with a yellow-brown root cross-section and stronger antioxidant properties. Given the poorly understood molecular mechanisms underlying these phenotypic differences, this study performed metabolomic and transcriptomic analyses to investigate the quality differences between the two types. Metabolomic analysis identified significant changes in 217 metabolites between the two types, among which 57 flavonoids, such as Hesperetin-7-O-glucoside, were significantly higher in the yellow-brown roots. Transcriptomic analysis revealed 3516 differentially expressed genes, many associated with flavonoid biosynthesis. Differences in root quality were largely attributed to varied flavonoid production. Analysis of transcription factors regulating this process identified a strong correlation between MYB6 genes and flavonoids biosynthesis. Functional analysis indicated that the ThMYB6 factor of the R2R3 MYB subgroup 5 regulates flavonoid production in T. hemsleyanum. This research establishes a theoretical foundation for enhancing the medicinal properties of T. hemsleyanum, while deepening our mechanistic understanding of flavonoid biosynthesis, thereby providing scientific support for the medicinal exploitation of T. hemsleyanum.