Guangdong Key Laboratory of Plant Molecular Breeding, College of Agriculture, South China Agricultural University, Guangzhou, 510642, China.
Plant Physiol Biochem. 2022 Jun 15;181:33-41. doi: 10.1016/j.plaphy.2022.04.004. Epub 2022 Apr 7.
Tartary buckwheat shows health benefits with its high antioxidant activity and abundant flavonoid content. However, glycosylated flavonoid accumulation patterns and their molecular basis remain unidentified in Tartary buckwheat. Here, our metabolomics analysis revealed that F3'H branching was the major flavonoid metabolic flux in Tartary buckwheat. Interestingly, metabolome results also showed that the most abundant flavonoids were mainly in the glycosylated form, including flavonoid glycosides and flavonoid diglycosides in Tartary buckwheat. However, the flavonoid glycosides glycosyltransferase (GGT) gene catalyzing the second glycosylation step of flavonoid diglycoside has not been discovered yet in Tartary buckwheat. Thus, we explored GGT genes in the transcriptome-metabolome correlation network and confirmed that FtUGT79A15 showed the rhamnosyltransferase activity to catalyze quercetin 3-O-glucoside to rutin invitro and inplanta. Overall, FtUGT79A15 was identified to involve in the flavonoid diglycoside biosynthesis pathway in Tartary buckwheat.
苦荞具有高抗氧化活性和丰富的类黄酮含量，对健康有益。然而，苦荞中糖基化类黄酮的积累模式及其分子基础仍不清楚。在这里，我们的代谢组学分析表明，F3'H 分支是苦荞中类黄酮代谢的主要途径。有趣的是，代谢组学结果还表明，含量最丰富的类黄酮主要以糖苷形式存在，包括苦荞中的类黄酮糖苷和类黄酮二糖苷。然而，催化类黄酮二糖苷第二步糖基化的类黄酮糖苷基转移酶（GGT）基因尚未在苦荞中发现。因此，我们在转录组-代谢组关联网络中探索了 GGT 基因，并证实 FtUGT79A15 具有鼠李糖基转移酶活性，能够在体外和体内将槲皮素 3-O-葡萄糖苷催化成芦丁。总的来说，FtUGT79A15 被鉴定为参与苦荞中类黄酮二糖苷的生物合成途径。
