Dual role and metabolic reprogramming: Key amino acids in marinade bidirectionally control aflatoxin B1 biosynthesis in Aspergillus parasiticus

This study revealed the effects and underlying mechanisms of key amino acids in marinade on A. parasiticus growth and aflatoxin B 1 (AFB 1 ) biosynthesis. Six key amino acids (with a concentration gradient of 0.5-8 g/L) from the marinade were selected and cultured them synchronously with A. parasiticus in this study. Solid/liquid culture combined with LC-MS/MS technology was used to analyse the effects of amino acids on colony growth, spore production, mycelial dry weight, and AFB 1 biosynthesis in A. parasiticus , and metabolomics was employed to elucidate the regulatory mechanisms of key amino acids. Results demonstrated that arginine, glycine, and lysine exhibited varying degrees of inhibitory effects. Specifically, 8 g/L lysine completely inhibited AFB 1 biosynthesis and significantly suppressed the mycelial growth. Proline, phenylalanine, and leucine remarkably promoted both the growth of A. parasiticus and AFB 1 production, with AFB 1 content reaching 324.50 ng/mL in the 8 g/L proline group, 3.45 times higher than in the control group. Metabolomic analysis indicated that proline synergistically enhanced AFB 1 biosynthesis by activating metabolic pathways, including the tricarboxylic acid (TCA) cycle and gibberellin metabolism. In contrast, lysine disrupted glucose metabolism and the TCA cycle, destroyed cell membrane integrity and inhibited A. parasiticus growth and toxin production at multiple levels. This study clarified the bidirectional regulatory effects and mechanisms of key amino acids in marinade, providing crucial technical references and theoretical foundations for controlling AFB 1 contamination in the production of marinated products by regulating marinade amino acid composition.