Amino acids promote the rejuvenation of degenerated Metarhizium anisopliae

• The metabolic profiles of normal and degenerated strains were analyzed using LC-MS. • Amino acids, especially Lysine, β-alanine, Arginine, and Glutamate, play a crucial role in M.anisopliae 's sporulation. • The optimal amino acid content in sporulation media was determined through single factor and response surface analysis. • Cultivating degenerated M.anisopliae with an optimized amino acid medium can effectively enhance sporulation while maintaining its virulence. Metarhizium anisopliae , an entomopathogenic fungus widely employed in agricultural and forestry pest control, faces challenges related to colony growth degradation and sporulation decline during industrial production and germplasm preservation. In this study, liquid chromatography-mass spectrometry (LC-MS) was used to detect the metabolomics of the normal strain and degenerated strain, enabling a comparison and analysis of their metabolic profiles. The results revealed significant differences in metabolic phenotypes among different strains of M.anisopliae , with amino acids playing a crucial role in spore production. Through single factor and response surface tests, optimal amino acid concentrations for sporulation media were determined as follows: lysine at 25.00 mg/L, β-alanine at 140.00 mg/L, arginine at 22.5 mg/L, glutamic acid at 155.00 mg/L. Cultivating degenerated M.anisopliae using this optimized amino acid medium resulted in approximately fivefold increase in sporulation without significantly affecting LT 50 values; thus indicating that the formulation promotes M.anisopliae ’s sporulation without compromising its virulence.