Proanthocyanidin subunit composition determined by functionally diverged dioxygenases
Proanthocyanidin subunit composition determined by functionally diverged dioxygenases
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DOI：
10.1038/s41477-018-0292-9
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发表时间：
2018-12-01
期刊：
影响因子：
18
通讯作者：
Dixon, Richard A.
中科院分区：
文献类型：
--
作者：
Jun, Ji Hyung;Xiao, Xirong;Dixon, Richard A.
原花青素（PAs）主要由黄烷-3-醇亚基(-)-表儿茶素和/或(+)-儿茶素组成，但它们不同的起始和延伸单元组成的基础尚不清楚。遗传和生化分析表明，在模型豆科植物中，花青素合成酶（anthocyanidin synthase， ANS）及其同源物白花色素双加氧酶（leooanthocyanidin dioxygenase， LDOX）通过平行途径分别生成PAs的(-)-表儿茶素延伸和起始单元，而（+）儿茶素是形成(-)-表儿茶素起始单元的中间体。LDOX途径的存在/缺失解释了不同物种间PA组成的自然差异，ANS或LDOX的工程功能丧失为获得不同组成和聚合程度的PA提供了一种方法，可用于食品和饲料。
Proanthocyanidins (PAs) are primarily composed of the flavan-3-ol subunits (-)-epicatechin and/or (+)-catechin, 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, anthocyanidin synthase (ANS) and its homologue leucoanthocyanidin dioxygenase (LDOX), 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.