This study investigated the dynamic changes of quality formation and metabolite profiles during the development of Morchella fruiting bodies. Morchella fruiting bodies at three developmental stages: primordium (YJ), small mushroom (XG), and mature ascocarp (ZNG) were used to identify key metabolites that affect the quality of the mushroom by the combined use of routine tests and untargeted metabolomics. The results demonstrated that during the growth and development of Morchella fruiting bodies, the contents of major nutritional components, including proteins, polysaccharides and crude fat, increased significantly (P < 0.05). Across the three developmental stages, 16 free amino acids including aspartic acid, glutamate and threonine, and 6 nucleotides including 5’-cytidine monophosphate (CMP), 5’-uridine monophosphate (UMP), and 5’-xanthosine monophosphate (XMP), were detected, and the total contents of free amino acids and nucleotides ranged from 1 291.01–5 857.72 mg/kg and 792.74–1 903.82 μg/g, respectively. Furthermore, untargeted metabolomics analysis identified 1 624 metabolites at these three developmental stages, predominantly comprising organic acids, amino acids and lipids. The vitamin B6 metabolism, riboflavin metabolism, arginine and proline metabolism, arginine biosynthesis, and nucleotide metabolism pathways were significantly enriched. Among 37 key differential metabolites involved in these significantly enriched pathways, 4-acetamidobutanoate and N6-(1,2-dicarboxyethyl)-adenosine monophosphate (AMP) were significantly positively correlated with the nutritional and flavor compounds of Morchella fruiting bodies, while L-arginine, agmatine, hypoxanthine, xanthine, deoxyinosine, inosine, and xanthosine were significantly negatively correlated with them. These metabolites participated in amino acid metabolism and energy metabolism during the growth of Morchella fruiting bodies, serving as potential factors regulating the quality formation of Morchella fruiting bodies
