Unraveling the Mechanism Underlying the Glycosylation and Methylation of Anthocyanins in Peach
Unraveling the Mechanism Underlying the Glycosylation and Methylation of Anthocyanins in Peach
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DOI：
10.1104/pp.114.246876
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发表时间：
2014-10-01
期刊：
影响因子：
7.4
通讯作者：
Han, Yuepeng
中科院分区：
文献类型：
--
作者：
Cheng, Jun;Wei, Guochao;Han, Yuepeng
花色苷的修饰对提高花色苷在植物体内的稳定性具有重要作用。在这里，六个花色苷鉴定桃（桃），其结构多样性归因于糖基化和甲基化。有趣的是，桃与野生种新疆杏非常相似，但在花的花青素组成方面与山桃和甘肃杏都不同。这表明桃很可能是从P. ferganensis驯化而来的。随后，负责花青素的甲基化和糖基化的基因被鉴定，并且它们的时空表达导致花、叶和果实中花青素积累的不同模式。桃类黄酮3-O-糖基转移酶（F3 GT）基因PpUGT 78 A1和PpUGT 78 A2对花色素苷的活性不同，为F3 GT基因在植物中的分化进化提供了一个例证。花色素苷O-甲基转移酶（AOMT）基因PpAOMT 1和PpAOMT 2在叶和花中均有表达，但只有PpAOMT 2负责桃花色素苷3'位的O-甲基化。此外，我们的研究揭示了一个新的分支的UGT 78基因在植物中，缺乏高度保守的内含子2的UGT基因家族，与一个巨大的变异的氨基酸残基的位置22的植物次级产物糖基转移酶框。我们的研究结果不仅提供了深入了解花青素糖基化和甲基化桃的机制，但也将有助于在未来的尝试操纵类黄酮的生物合成桃以及在其他植物。
Modification of anthocyanin plays an important role in increasing its stability in plants. Here, six anthocyanins were identified in peach (Prunus persica), and their structural diversity is attributed to glycosylation and methylation. Interestingly, peach is quite similar to the wild species Prunus ferganensis but differs from both Prunus davidiana and Prunus kansueasis in terms of anthocyanin composition in flowers. This indicates that peach is probably domesticated from P. ferganensis. Subsequently, genes responsible for both methylation and glycosylation of anthocyanins were identified, and their spatiotemporal expression results in different patterns of anthocyanin accumulation in flowers, leaves, and fruits. Two tandem-duplicated genes encoding flavonoid 3-O-glycosyltransferase (F3GT) in peach, PpUGT78A1 and PpUGT78A2, showed different activity toward anthocyanin, providing an example of divergent evolution of F3GT genes in plants. Two genes encoding anthocyanin O-methyltransferase (AOMT), PpAOMT1 and PpAOMT2, are expressed in leaves and flowers, but only PpAOMT2 is responsible for the O-methylation of anthocyanins at the 3' position in peach. In addition, our study reveals a novel branch of UGT78 genes in plants that lack the highly conserved intron 2 of the UGT gene family, with a great variation of the amino acid residue at position 22 of the plant secondary product glycosyltransferase box. Our results not only provide insights into the mechanisms underlying anthocyanin glycosylation and methylation in peach but will also aid in future attempts to manipulate flavonoid biosynthesis in peach as well as in other plants.