Comprehensive Analysis of Metabolic Fluxes from Leucoanthocyanins to Anthocyanins and Proanthocyanidins (PAs)
Comprehensive Analysis of Metabolic Fluxes from Leucoanthocyanins to Anthocyanins and Proanthocyanidins (PAs)
复制标题
从无色花青素到花青素和原花青素 (PA) 的代谢通量的综合分析
DOI：
10.1021/acs.jafc.0c05048
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发表时间：
2020
影响因子：
6.1
通讯作者：
Xia Tao
中科院分区：
文献类型：
--
作者：
Wang Peiqiang;Zhang Lingjie;Zhao Lei;Zhang Xinfu;Zhang Hanghang;Han Yahui;Jiang Xiaolan;Liu Yajun;Gao Liping;Xia Tao
花青素和PAS是两种最常见的黄酮类化合物，广泛存在于不同的物种中。在它们的合成和调控方面取得了很大的进展。在本研究中，我们分析了二氢黄酮醇4-还原酶(DFR)在体外和体内过表达所获得的合成前体亮色花青素的代谢通量。在弱酸性条件下，CsDFRa酶促反应生成的不稳定产物亮蓝很容易转化为C型碳正离子，可进一步参与体外合成C型多糖类化合物。此外，还研究了烟草高表达CsDFRaa和拟南芥DFR和花青素合成酶(ANS)突变体中的代谢产物。CsDFR转基因烟草花瓣花色苷含量显著增加，但未检测到儿茶素和PA。艾娜。突变体Taliana中，EC型碳正离子主要积累在野生型(WT)中，而C型碳正离子仅在突变体中检测到。在茶树中，C型多胺的积累与CsDFRa的表达呈显著正相关。综上所述，亮氰素不仅参与下游花青素和表儿茶素的合成，而且还可以转化为C型碳正离子参与C型多胺的合成。因此，从亮蓝蛋白出发，形成了向儿茶素、氰化物和C型碳正离子的三种代谢通量。这些结果丰富了亮氨酸花色苷的代谢通量，进一步阐明了DFR在C型PA形成过程中的作用。
Anthocyanins and PAs are the two most common flavonoids, which are widely present among diverse species. Great progress has been made in their synthesis and regulation. In this study, we analyzed the metabolic fluxes from their synthetic precursor leucoanthocyanins, which were obtained by overexpression of dihydroflavonol 4-reductase (DFR)in vitroandin vivo. The unstable product leucocyanidin generated in the CsDFRa enzymatic reaction was easily converted into C-type carbocations under weak acidic conditions, which could be further involved in the synthesis of C-type PAsin vitro. Additionally, the metabolites in tobacco overexpressingCsDFRaandArabidopsis thalianaDFR and anthocyanidin synthase (ANS) mutants were investigated. InCsDFRatransgenic tobacco, the content of anthocyanins in the petals was greatly increased, but no catechin or PA was detected. InA. thaliana, EC-type carbocation was mainly accumulated in the wild type (WT), and the C-type carbocation was only detected in theansmutant. In tea plant, the accumulation of C-type PAs is strong positively correlated with the expression ofCsDFRa. In summary, leucocyanidin is not only involved in the synthesis of downstream anthocyanin and epicatechin but also can be converted into C-type carbocation to participate in the synthesis of C-type PAs. Hence, from leucocyanidin, three metabolic fluxes were formed toward catechin, cyanidin, and C-type carbocation. These results enriched the metabolic fluxes of leucoanthocyanins and further elaborated the roles of DFR in the process of C-type PA formation.