Multi‐Omics Analyses Reveal Key Factors Involved in Genistein Accumulation in <i>Flemingia macrophylla</i> Exposed to Different Magnesium Concentrations

Flemingia macrophylla (Willd.) Merr. is commonly used as ethnic medicine in southwestern China, with genistein and genistin being the primary medicinal components. Magnesium has a significant impact on the growth, development, and accumulation of these active ingredients in F. macrophylla. To explore the effects of magnesium on the growth, development, and accumulation of active ingredients in F. macrophylla, tissue culture seedlings of F. macrophylla were treated with six different concentrations of magnesium, namely, T0 (0 g L^-1), T0.5 (0.045 g L^-1), T1 (0.09 g L^-1), T2 (0.18 g L^-1), T3 (0.27 g L^-1), and T4 (0.36 g L^-1), and then subjected to multi-omic analyses. Analysis of agronomic traits revealed that magnesium treatment significantly promoted rooting, whereas magnesium deficiency restricted root growth. Simultaneously, analysis of seedlings using high-performance liquid chromatography showed that 0.27 and 0.36 g L^-1 magnesium significantly enhanced genistein synthesis and inhibited glycosylation (genistin). Furthermore, transcriptomic, proteomic, and metabolomic analyses indicated that differentially expressed genes and proteins under varying magnesium concentrations were primarily involved in phenylpropanoid, isoflavone, and flavonoid biosyntheses. Specifically, eight gene-protein pairs related to the synthesis of genistein and genistin were identified. Overall, our study identified essential genes/proteins involved in the synthesis of these two compounds and provided new ways to regulate genistein synthesis in medicinal plants.