Integrated Transcriptomic and Metabolic Framework for Carbon Metabolism and Plant Hormones Regulation in Vigna radiata during Post-Germination Seedling Growth

During mung bean post-germination seedling growth, various metabolic and physiological changes occurred, leading to the improvement of its nutritional values. Here, transcriptomic and metabolomic analyses of mung bean samples from 6-hour, 3-day and 6-day after imbibition (6-HAI, 3-DAI, and 6-DAI) were performed to characterize the regulatory mechanism of the primary metabolites during the post-germination seedling growth. From 6-HAI to 3-DAI, rapid changes in transcript level occurred, including starch and sucrose metabolism, glycolysis, citrate cycle, amino acids synthesis, and plant hormones regulation. Later changes in the metabolites, including carbohydrates and amino acids, appeared to be driven by increases in transcript levels. During this process, most amino acids and monosaccharides kept increasing, and accumulated in 6-day germinated sprouts. These processes were also accompanied with changes in hormones including abscisic acid, gibberellin, jasmonic acid, indole-3-acetic acid, etc. Overall, these results will provide insights into molecular mechanisms underlying the primary metabolic regulation in mung bean during post-germination seedling growth.