Transcriptomic and metabolomic investigation of metabolic disruption in Vigna unguiculata L. triggered by acetamiprid and cyromazine

A variety of pesticides are often used in agricultural management to control target pests but may trigger disruptions in the metabolism of nontarget organisms, ultimately affecting crop quality. Acetamiprid (ACE) and cyromazine (CYR) are two frequently used insecticides on cowpea, so it is critical to understand whether these two insecticides cause metabolic disorders in cowpea quality changes and the mechanism by which they do so. Here, we used metabolomic and transcriptomic methods to explore the mechanisms of the effects of ACE, CYR, and their mixture (MIX) on cowpea. In this study, ACE, CYR and MIX had no significant effects on plant biomass or growth status but decreased the contents of starch, soluble protein, and total flavonoids. All treatments reduced the total flavonoid content, but MIX showed the largest reduction of 10.02%. Metabolomic and transcriptomic analyses revealed that ACE markedly affected amino acid metabolism, and CYR and MIX affected sugar metabolism and flavonoid synthesis pathways. ACE and CYR reduced the levels of alanine, glutamic acid, isoleucine and phenylalanine and the expression of amino acid-related genes in cowpea, while MIX significantly increased the levels of most amino acids. All pesticide treatments reduced saccharide levels and related genes, with the most pronounced reduction in the MIX treatment. Exposure to ACE decreased the content of naringenin chalcone and quercetin and increased the content of anthocyanins in cowpeas, while MIX caused a significant decrease in the contents of quercetin and anthocyanins. According to the current study, single and mixed pesticides had different effects on the active ingredients of cowpea, with MIX causing the most significant decrease in the metabolite content of cowpea. These results provide important insights from a molecular perspective on how neonicotinoids and triazine insecticides affect cowpea metabolism.