Proanthocyanidin subunit composition determined by functionally diverged dioxygenases

First author: Ji Hyung Jun; Affiliations: University of North Texas (北德克萨斯州大学): Denton, USA

Corresponding author: Richard A. Dixon

Proanthocyanidins (PAs; 原花青素) are primarily composed of the flavan-3-ol (黄烷-3-醇) subunits (-)-epicatechin (表儿茶素) and/or (+)-catechin (儿茶素), but the basis for their different starter and extension unit compositions remains unclear. Genetic and biochemical analyses show that, in the model legume Medicago truncatula, two 2-oxoglutarate-dependent dioxygenases (2-酮戊二酸依赖性双加氧酶), anthocyanidin synthase (ANS) and its homologue leucoanthocyanidin dioxygenase (LDOX; 无色花色素双加氧酶), are involved in parallel pathways to generate, respectively, the (-)-epicatechin extension and starter units of PAs, with (+) catechin being an intermediate in the formation of the (-)-epicatechin starter unit. The presence/absence of the LDOX pathway accounts for natural differences in PA compositions across species, and engineering loss of function of ANS or LDOX provides a means to obtain PAs with different compositions and degrees of polymerization for use in food and feed.

原花青素主要由黄烷-3-醇亚基(-)-表儿茶素和(+)-儿茶素构成，但其起始物以及延伸单位组成的基础还不清楚。遗传学和生化试验显示模式豆科植物苜蓿中的两个2-酮戊二酸依赖性双加氧酶：原花青素合酶ANS和同源的无色花色素双加氧酶LDOX参与了两条平行的通路分别产生(-)-表儿茶素的延伸和原花青素的起始单位，而(+)-儿茶素是形成(-)-表儿茶素起始单位途径的中间产物。LDOX通路的存在或缺失导致了不同物种原花青素组成的自然差异，并且人为导致的ANS或LDOX功能丢失会获得不同组分或不同聚合程度的原花青素用于食物和饲料。

通讯：Richard A. Dixon (https://biology.unt.edu/prof-richard-dixon)

个人简介：牛津大学，生物化学和生物学博士；剑桥大学，植物生物化学博士后。

研究方向：植物自然产物的生物化学、分子生物学及代谢研究。

doi: https://doi.org/10.1038/s41477-018-0292-9

Journal: Nature Plants

Published date: 26 November, 2018