Flavonoids in grapes contribute the quality of the berry, but the flavonoid diversity and the regulatory networks underlying the variation require a further investigation. In this study, we integrated multi-omics data to systematically explore the global metabolic and transcriptional profiles in the skins and pulps of three grape cultivars. The results revealed large-scale differences involved in the flavonoid metabolic pathway. A total of 133 flavonoids, including flavone and flavone C-glycosides, were identified. Beyond the visible differences of anthocyanins, there was large variation in other sub-branched flavonoids, most of which were positively correlated with anthocyanins in grapes. The expressions of most flavonoid biosynthetic genes and the major regulators MYBA1 were strongly consistent with the changes in flavonoids. Integrative analysis identified two novel transcription factors (MYB24 and MADS5) and two ubiquitin proteins (RHA2) as promising regulatory candidates for flavonoid biosynthesis in grapes. Further verification in various grape accessions indicated that five major genes including flavonol 3′5′-hydroxylase (F3′5′H), UDP-glucose:flavonoid 3-O-glycosyl-transferase, anthocyanin O-methyltransferase, acyltransferase (3AT), and glutathione S-transferase (GST4) controlled flavonoid variation in grape berries. These findings provide valuable information for understanding the mechanism of flavonoid biosynthesis in grape berries and the further development of grape health products.

中文翻译：

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代谢组和转录组的综合分析提供了对葡萄浆果中类黄酮变异的深入了解

葡萄中的类黄酮有助于浆果的品质，但类黄酮的多样性和变异背后的调控网络需要进一步研究。在这项研究中，我们整合了多组学数据，系统地探索了三个葡萄品种的果皮和果肉中的全局代谢和转录谱。结果揭示了类黄酮代谢途径中涉及的大规模差异。共鉴定出133 种黄酮类化合物，包括黄酮和黄酮C-糖苷。除了花青素的明显差异外，其他亚支化类黄酮也存在很大差异，其中大部分与葡萄中的花青素呈正相关。大多数类黄酮生物合成基因的表达和主要调控因子MYBA1与黄酮类化合物的变化高度一致。综合分析确定了两个新的转录因子（MYB24和MADS5）和两个泛素蛋白（RHA2）作为葡萄类黄酮生物合成的有希望的调节候选物。进一步在多个葡萄种质中验证，黄酮醇3′5′-羟化酶（F3′5′H）、UDP-葡萄糖：黄酮类3-O-糖基转移酶、花青素O-甲基转移酶、酰基转移酶（3AT）等5个主要基因，和谷胱甘肽 S-转移酶( GST4) 控制葡萄浆果中类黄酮的变化。这些发现为理解葡萄浆果中黄酮类化合物的生物合成机制和进一步开发葡萄保健品提供了有价值的信息。