Elucidating the biosynthetic and regulatory mechanisms of flavonoid-derived bioactive components in Epimedium sagittatum.
Elucidating the biosynthetic and regulatory mechanisms of flavonoid-derived bioactive components in Epimedium sagittatum.
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阐明箭叶淫羊藿中黄酮类生物活性成分的生物合成和调控机制
DOI：
10.3389/fpls.2015.00689
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发表时间：
2015
影响因子：
5.6
通讯作者：
Wang Y
中科院分区：
文献类型：
--
作者：
Huang W;Zeng S;Xiao G;Wei G;Liao S;Chen J;Sun W;Lv H;Wang Y
淫羊藿（Epimedium）是一种中药，几千年来一直被广泛用作补肾和抗风湿药。淫羊藿中黄酮类化合物是主要的生物活性成分。然而，黄酮类化合物的分子生物合成及其调控机制尚不清楚。在这项研究中，我们分离了12个结构基因和两个推测的转录因子（TFs）。植物化学分析表明，两系矢状淫羊藿在叶片发育过程中4种具有代表性的BCs（淫羊藿苷A、B、C和淫羊藿苷）的总含量略有或显著下降。转录分析表明，两个R2R3-MYB TF （EsMYBA1和EsMYBF1）与bHLH TF （EsGL3）和WD40蛋白（EsTTG1）协同调节叶片花青素和黄酮醇类BCs的生物合成。烟草黄酮醇合成酶（EsFLS）过表达导致花中黄酮醇含量升高，花青素含量降低。此外，EsMYB12与四种BCs的积累呈负相关，可能在类黄酮途径中作为转录抑制因子。因此，花青素途径可能与淫羊藿叶片黄酮醇衍生的BCs途径协同作用。更好地了解淫羊藿类黄酮的生物合成及其调控机制将为淫羊藿的功能表征、代谢工程和分子育种研究提供依据。
Herba epimedii (Epimedium), a traditional Chinese medicine, has been widely used as a kidney tonic and antirheumatic medicine for thousands of years. In Epimedium, flavonoids have been demonstrated to be the main bioactive components (BCs). However, the molecular biosynthetic and regulatory mechanisms of flavonoid-derived BCs remain obscure. In this study, we isolated 12 structural genes and two putative transcription factors (TFs) in the flavonoid pathway. Phytochemical analysis showed that the total content of four representative BCs (epimedin A, B, C, and icariin) decreased slightly or dramatically in two lines of Epimedium sagittatum during leaf development. Transcriptional analysis revealed that two R2R3-MYB TFs (EsMYBA1 and EsMYBF1), together with a bHLH TF (EsGL3) and WD40 protein (EsTTG1), were supposed to coordinately regulate the anthocyanin and flavonol-derived BCs biosynthesis in leaves. Overexpression of EsFLS (flavonol synthase) in tobacco resulted in increased flavonols content and decreased anthocyanins content in flowers. Moreover, EsMYB12 negatively correlated with the accumulation of the four BCs, and might act as a transcriptional repressor in the flavonoid pathway. Therefore, the anthocyanin pathway may coordinate with the flavonol-derived BCs pathway in Epimedium leaves. A better understanding of the flavonoid biosynthetic and regulatory mechanisms in E. sagittatum will facilitate functional characterization, metabolic engineering, and molecular breeding studies of Epimedium species.