Wang Wenzhao, Zhou Yihui, Wu Yingling, Dai Xinlong, Liu Yajun, Qian Yumei, Li Mingzhuo, Jiang Xiaolan, Wang Yunsheng, Gao Liping, Xia Tao
State Key Laboratory of Tea Plant Biochemistry and Utilization , Anhui Agricultural University , Hefei 230036 , China.
School of Life Science , Anhui Agricultural University , Hefei 230036 , China.
J Agric Food Chem. 2018 Apr 25;66(16):4281-4293. doi: 10.1021/acs.jafc.8b00946. Epub 2018 Apr 10.
Tea is an important economic crop with a 3.02 Gb genome. It accumulates various bioactive compounds, especially catechins, which are closely associated with tea flavor and quality. Catechins are biosynthesized through the phenylpropanoid and flavonoid pathways, with 12 structural genes being involved in their synthesis. However, we found that in Camellia sinensis the understanding of the basic profile of catechins biosynthesis is still unclear. The gene structure, locus, transcript number, transcriptional variation, and function of multigene families have not yet been clarified. Our previous studies demonstrated that the accumulation of flavonoids in tea is species, tissue, and induction specific, which indicates that gene coexpression patterns may be involved in tea catechins and flavonoids biosynthesis. In this paper, we screened candidate genes of multigene families involved in the phenylpropanoid and flavonoid pathways based on an analysis of genome and transcriptome sequence data. The authenticity of candidate genes was verified by PCR cloning, and their function was validated by reverse genetic methods. In the present study, 36 genes from 12 gene families were identified and were accessed in the NCBI database. During this process, some intron retention events of the CsCHI and CsDFR genes were found. Furthermore, the transcriptome sequencing of various tea tissues and subcellular location assays revealed coexpression and colocalization patterns. The correlation analysis showed that CsCHIc, CsF3'H, and CsANRb expression levels are associated significantly with the concentration of soluble PA as well as the expression levels of CsPALc and CsPALf with the concentration of insoluble PA. This work provides insights into catechins metabolism in tea and provides a foundation for future studies.
茶是一种重要的经济作物，其基因组大小为3.02 Gb。它积累了多种生物活性化合物，尤其是儿茶素，这些化合物与茶的风味和品质密切相关。儿茶素通过苯丙烷类和类黄酮途径生物合成，有12个结构基因参与其合成。然而，我们发现对于茶树中儿茶素生物合成的基本概况仍不清楚。多基因家族的基因结构、位点、转录本数量、转录变异和功能尚未阐明。我们之前的研究表明，茶中类黄酮的积累具有物种、组织和诱导特异性，这表明基因共表达模式可能参与了茶儿茶素和类黄酮的生物合成。在本文中，我们基于对基因组和转录组序列数据的分析，筛选了参与苯丙烷类和类黄酮途径的多基因家族的候选基因。通过PCR克隆验证了候选基因的真实性，并通过反向遗传学方法验证了它们的功能。在本研究中，从12个基因家族中鉴定出36个基因，并将其提交到NCBI数据库。在此过程中，发现了CsCHI和CsDFR基因的一些内含子保留事件。此外，对各种茶组织的转录组测序和亚细胞定位分析揭示了共表达和共定位模式。相关性分析表明，CsCHIc、CsF3'H和CsANRb的表达水平与可溶性PA的浓度显著相关，而CsPALc和CsPALf的表达水平与不溶性PA的浓度相关。这项工作为茶中儿茶素代谢提供了见解，并为未来的研究奠定了基础。
