Metabolomics and Transcriptomics Analyses Explore the Genes Related to the Biosynthesis of Antioxidant Active Ingredient Isoquercetin

<i>Astragalus membranaceus</i> is a model of traditional 'homologous nature of medicine and food'. Its stems and leaves have been proven to have a variety of biological activities. In this study, high-throughput sequencing technology was used to sequence transcriptomics and metabolomics <i>A. membranaceus</i> stems and leaves at different growth stages (flowerless stage, flower bud stage, flowering stage, green fruit stage, mature fruit staged, and withering stage), and a regulation analysis was conducted on its differentially expressed genes and differentially accumulated metabolites. The results showed that five hub genes, <i>PAL</i>, <i>CHI</i>, <i>AMIE</i>, <i>CAD</i>, and <i>PRX</i>, were found to play a central regulatory role in flavonoid biosynthesis. The combined analysis of transcriptomics and metabolomics constructed a flavonoid metabolic regulatory network during the growth and development of <i>A. membranaceus</i> stems and leaves. At the same time, based on the significant antioxidant activity of isoquercitrin, three genes that may be related to isoquercitrin biosynthesis were screened, namely <i>IF7MAT</i>, <i>FG3</i>, and <i>UGT78D2</i>. The results of this study provide insights into the biosynthesis and comprehensive development and utilization of flavonoids in <i>A. membranaceus</i>.