Overlapping Transcriptome\nAlterations Reveal the Mechanism\nof Interaction between Selenium and Zinc and Their Common Effect on\nEssential Nutrient Metabolism in Mung Bean (<i>Vigna radiata</i> L.)

Selenium (Se) and zinc (Zn) deficiencies have become\nserious global\nfood security and public health problems. Biofortification through\nfoliar fertilizer is a nonspecific, low-tech, and cost-effective strategy.\nSe and Zn have overlapping physiological roles and interacting relationships\nin plants. Mung bean is superior for Se enrichment and an excellent\nZn carrier. However, the molecular mechanism underlying the interaction\nbetween Se and Zn in the mung\nbean remains unclear. Herein, Se and Zn accumulation, antioxidant\nactivities, physiological determination, and transcriptomic analysis\nwere performed under both Se and Zn treatments. Common essential roles\nof Se and Zn in mung bean were reflected by the comprehensively altered\nten physiological indexes under both Se2 (24 g·ha<sup>–1</sup>) and Zn1 (1.2 kg·ha<sup>–1</sup>) treatments. Overlapping\ntranscriptome changes and common DEGs in two compared groups revealed\nthat the upregulated expression of sulfate transporters (SULTRs),\nphosphate transporters (PHTs), and Zinc-regulated/Iron-regulated-like\nprotein (ZIP) family genes under Se and Zn treatments directly promoted\nboth Se and Zn intakes. Furthermore, the altered Se/Sulfur, nitrogen,\nand carbohydrate metabolisms are closely interlinked with the uptake\nand assimilation of Se and Zn via the 20 key genes that we filtered\nthrough the protein–protein interaction (PPI) network analysis.\nFurther analysis indicated that l-methionine γ-lyase\n(E 4.4.1.11) genes may play an important role in the transamination\nof selenomethionine and its derivatives; glutamine synthetase (GS),\nnitrate reductase (NR), and starch synthase (SS) genes may regulate\nthe nitrogen assimilation and carbohydrate metabolism, which provide\nmore carriers for Se and Zn; glutathione peroxidase (GPx), glutamate-cysteine\nligase catalytic subunit (GCLC), and serine acetyltransferase (SAT)\ngenes may accelerate the GSH-GSSH cycle and promote Se and Zn storages.\nThis study provides new molecular insights into the comprehensive\nimprovement of the nutritional quality of mung beans in Se and Zn\nbiofortification productions.