Functional characterization of three flavonol synthase genes from Camellia sinensis: Roles in flavonol accumulation
Functional characterization of three flavonol synthase genes from Camellia sinensis: Roles in flavonol accumulation
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茶花中三种黄酮醇合酶基因的功能特征：在黄酮醇积累中的作用
DOI：
10.1016/j.plantsci.2020.110632
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发表时间：
2020-11-01
期刊：
影响因子：
5.2
通讯作者：
Xia, Tao
中科院分区：
文献类型：
--
作者：
Jiang, Xiaolan;Shi, Yufeng;Xia, Tao
黄酮醇衍生物是一类对人体有益的黄酮类化合物。他们在茶中的大量存在与涩味有关。迄今为止，茶树黄酮醇类化合物生物合成的机理仍不清楚。在这项研究中，我们使用生物信息学分析挖掘茶叶基因组，并获得了三个cDNA注释为黄酮醇脱氢酶（FLS）。三种cDNA，即CsFLSa、B和C，在大肠杆菌中异源表达。大肠杆菌中诱导表达重组蛋白，并将重组蛋白与三种底物二氢甘普非醇（DHK）、二氢槲皮素（DHQ）和二氢杨梅素（DHM）共同孵育。所得数据显示三种rCsFLS优选催化（DHK）。在烟草中过量表达这两种cDNA都导致了花中的kampferol含量的增加和花色素苷含量的减少。进一步代谢分析的黄烷-3-醇在年轻的茶芽的特点是山奈酚衍生物是最丰富的，其次是槲皮素，然后杨梅素衍生物。综上所述，这些数据特征的关键步骤致力于茶叶中黄酮醇的生物合成。此外，这些数据增强了对茶叶中黄酮醇与其他主要黄酮类化合物（如黄烷-3-醇）之间代谢积累相关性的理解。
Flavonol derivatives are a group of flavonoids benefiting human health. Their abundant presence in tea is associated with astringent taste. To date, mechanism pertaining to the biosynthesis of flavonols in tea plants remains unknown. In this study, we used bioinformatic analysis mining the tea genome and obtained three cDNAs that were annotated to encode flavonol synthases (FLS). Three cDNAs, namely CsFLSa, b, and c, were heterogenously expressed in E. coli to induce recombinant proteins, which were further used to incubate with three substrates, dihydrokampferol (DHK), dihydroquercetin (DHQ), and dihydromyricetin (DHM). The resulting data showed that three rCsFLSs preferred to catalyze (DHK). Overexpression of each cDNA in tobacco led to the increase of kampferol and the reduction of anthocyanins in flowers. Further metabolic profiling of flavan-3-ols in young tea shoots characterized that kaempferol derivatives were the most abundant, followed by quercetin and then myricetin derivatives. Taken together, these data characterized the key step committed to the biosynthesis of flavonols in tea leaves. Moreover, these data enhance understanding the metabolic accumulation relevance between flavonols and other main flavonoids such as flavan-3-ols in tea leaves.