Flavonoid glycosides are widespread in plants, and are of great interest owing to their diverse biological activities and effectiveness in preventing chronic diseases. , a renowned medicinal plant of the Apocynaceae family, contains diverse flavonoid glycosides and is clinically used to treat rheumatoid arthritis and traumatic injuries. However, the mechanisms underlying the biosynthesis of these flavonoid glycosides have not yet been elucidated. In this study, we used widely targeted metabolomics and full-length transcriptome sequencing to identify flavonoid diversity and biosynthetic genes in . A total of 120 flavonoid glycosides, including 21 -, 96 -, and 3 -glycosides, were identified and annotated. Based on 24,123 full-length coding sequences, 99 uridine diphosphate sugar-utilizing glycosyltransferases (UGTs) were identified and classified into 14 groups. Biochemical assays revealed that four UGTs exhibited -glycosyltransferase activity toward apigenin and luteolin. Among them, PfUGT74B4 and PfUGT92A8 were highly promiscuous and exhibited multisite -glycosylation or consecutive glycosylation activities toward various flavonoid aglycones. These four glycosyltransferases may significantly contribute to the diversity of flavonoid glycosides in . Our findings provide a valuable genetic resource for further studies on and insights into the metabolic engineering of bioactive flavonoid glycosides.

中文翻译：

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多组学分析揭示混杂的O-糖基转移酶参与夹竹桃科黄酮苷的多样性

黄酮苷广泛存在于植物中，由于其多样化的生物活性和预防慢性疾病的功效而引起人们极大的兴趣。夹竹桃科著名药用植物，含有多种黄酮苷，临床用于治疗类风湿性关节炎和跌打损伤。然而，这些黄酮苷生物合成的机制尚未阐明。在这项研究中，我们使用广泛靶向的代谢组学和全长转录组测序来鉴定黄酮类化合物的多样性和生物合成基因。共鉴定并注释了 120 种黄酮苷，包括 21-、96-和 3-糖苷。基于 24,123 个全长编码序列，鉴定出 99 种尿苷二磷酸糖利用糖基转移酶 (UGT)，并将其分为 14 组。生化分析表明，四种 UGT 对芹菜素和木犀草素表现出 β-糖基转移酶活性。其中，PfUGT74B4和PfUGT92A8高度混杂，并对各种黄酮苷元表现出多位点糖基化或连续糖基化活性。这四种糖基转移酶可能对黄酮苷的多样性有显着贡献。我们的研究结果为进一步研究和深入了解生物活性黄酮苷的代谢工程提供了宝贵的遗传资源。