Ye Ying, Liu Ru-Yi, Li Xin, Zheng Xin-Qiang, Lu Jian-Liang, Liang Yue-Rong, Wei Chao-Ling, Xu Yong-Quan, Ye Jian-Hui
Tea Research Institute, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China.
Key Laboratory of Tea Biology and Resources Utilization, Ministry of Agriculture, Tea Research Institute Chinese Academy of Agricultural Sciences, Hangzhou 310000, China.
Hortic Res. 2023 Nov 17;11(1):uhad231. doi: 10.1093/hr/uhad231. eCollection 2024 Jan.
Flavonoids are important compounds in tea leaves imparting bitter and astringent taste, which also play key roles in tea plants responding to environmental stress. Our previous study showed that the expression level of was positively correlated with the accumulation of flavonoids in tea leaves as exposed to sunlight. Here, we newly reported the function of CsMYB67 in regulating flavonoid biosynthesis in tea leaves. CsMYB67 was localized in the nucleus and responded to temperature. The results of transient expression assays showed the co-transformation of and promoted the transcription of promoter in the tobacco system. CsTTG1 was bound to the promoter of based on the results of yeast one-hybrid (Y1H) and transient expression assays, while CsMYB67 enhanced the transcription of through protein interaction with CsTTG1 according to the results of yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC). Thus, CsMYB67-CsTTG1 module enhanced the anthocyanin biosynthesis through up-regulating the transcription of . Besides, CsMYB67 also enhanced the transcription of and through forming transcription factor complexes. The function of on flavonoid biosynthesis in tea leaves was validated by gene suppression assay. As was suppressed, the transcriptional level of was greatly reduced, leading to a significant increase in the contents of total catechins and total anthocyanidins. Hence, CsMYB67 plays an important role in regulating the downstream pathway of flavonoid biosynthesis in summer tea leaves.
黄酮类化合物是茶叶中的重要化合物，赋予茶叶苦涩味，在茶树应对环境胁迫中也起着关键作用。我们之前的研究表明，[此处原文缺失相关基因名称]的表达水平与暴露于阳光下的茶叶中黄酮类化合物的积累呈正相关。在此，我们首次报道了CsMYB67在调节茶叶黄酮类生物合成中的功能。CsMYB67定位于细胞核并对温度作出响应。瞬时表达分析结果表明，[此处原文缺失相关基因名称]和[此处原文缺失相关基因名称]的共转化在烟草系统中促进了[此处原文缺失相关基因名称]启动子的转录。基于酵母单杂交（Y1H）和瞬时表达分析结果，CsTTG1与[此处原文缺失相关基因名称]的启动子结合，而根据酵母双杂交（Y2H）和双分子荧光互补（BiFC）结果，CsMYB67通过与CsTTG1的蛋白相互作用增强了[此处原文缺失相关基因名称]的转录。因此，CsMYB67-CsTTG1模块通过上调[此处原文缺失相关基因名称]的转录增强了花青素的生物合成。此外，CsMYB67还通过形成转录因子复合物增强了[此处原文缺失相关基因名称]和[此处原文缺失相关基因名称]的转录。通过基因抑制试验验证了[此处原文缺失相关基因名称]在茶叶黄酮类生物合成中的功能。随着[此处原文缺失相关基因名称]被抑制，[此处原文缺失相关基因名称]的转录水平大幅降低，导致总儿茶素和总花青素含量显著增加。因此，CsMYB67在调节夏茶黄酮类生物合成的下游途径中起重要作用。
