转录因子CsMYB113在茶树花青苷积累中的功能研究与调控机制解析

Anthocyanins are the important functional components in the ‘Zijuan’ tea. Tea from anthocyanin-rich cultivar ‘Zijuan’ can become specialty teas benefit for human health by its high antioxidant activity. About regulation mechanisms of anthocyanin accumulation in ‘Zijuan’ tea, however, is still unknown. In our previous study, we obtained a CsMYB113 transcription factor which significantly up-regulated in the anthocyanin accumulated tissues of ‘Zijuan’ tea based on comparative transcriptome in combined with qRT-PCR analysis. We also found that the expression levels of the CsMYB113 transcription factor showed a good correlation with the anthocyanin content in different tissues of ‘Zijuan’. These results suggested that the CsMYB113 transcription factor may play an important role in the anthocyanin metabolism regulation of tea plants. In order to understand the CsMYB113 transcription factor’s function involved in anthocyanin mechanism, an overexpression vector will be constructed to transform tobacco. The functional analysis of CsMYB113 will be performed by phenotypic characteristics, expression of anthocyanin metabolism related genes, and biochemical measurement. Moreover, we will try to identify proteins and structural genes interacted with CsMYB113 transcription factor using Yeast Two Hybrid System and EMSA assays, respectively. The study will help to find out the functional roles of CsMYB113 transcription factor in the anthocyanin mechanism regulation in tea plants, and consequently provide theory evidence for the anthocyanin mechanism regulation and modification.

花青苷是茶树特色资源‘紫鹃’中重要的功能成分。利用‘紫鹃’做成的茶具有很高的抗氧化活性，对人体健康具有十分重要的作用。然而，‘紫鹃’中花青苷积累的分子机制至今不明晰。申请人前期通过比较转录组结合qRT-PCR分析发现一个MYB转录因子CsMYB113在‘紫鹃’花青苷积累的芽叶组织中显著上调表达，并且其表达量与各组织间的花青苷含量呈现良好的相关性，暗示该转录因子很有可能与茶树花青苷代谢调控相关。本项目拟通过构建超量表达载体转化烟草，结合植株表型观察、花青苷代谢相关基因表达以及生理生化指标测定探讨CsMYB113的生物学功能，进而利用酵母双杂和凝胶阻滞技术明确其互作蛋白及下游调控的结构基因，解析CsMYB113基因的调控机制。本项目的开展将有助于我们深入解析转录因子CsMYB113在茶树花青苷代谢调控中的功能及作用机制，进而为茶树花青苷代谢的调控和改良提供理论依据。

花青苷具有很高的抗氧化活性，对人体健康具有十分重要的作用。然而，茶树中花青苷积累的分子机制至今不明晰。本研究旨在研究CsMYB113基因的生物学功能，并对其调控机制进行初步解析，主要研究结果如下：.1.通过比较转录组筛选到差异表达的CsMYB113基因，该基因属于R2R3型MYB转录因子。亚细胞定位表明CsMYB113基因定位于细胞核。CsMYB113基因的组织表达特性研究发现，该基因的在芽中的表达量较高，并随着叶片成熟，表达量有所下降，且在根中的表达量显著高于叶片。2.超量表达拟南芥后发现，CsMYB113基因能够显著提高转基因株系叶片、茎、根及种子中的花青素含量。qRT-PCR分析结果表明，超量表达CsMYB113基因后可以显著提高LOX、F3H、CHI、DFR等基因的表达。推测CsMYB113基因可以通过上调上述基因的表达量从而提高花青苷的含量。3.茶树瞬时表达结果也表明CsMYB113基因可以提高茶树花青苷含量。.本项目的开展将有助于我们深入解析转录因子CsMYB113在茶树花青苷代谢调控中的功能及作用机制，进而为茶树花青苷代谢的调控和改良提供理论依据。