Comparative Metabolomics Reveals the Nutritional Merit and Metabolic Basis of a Naturally Occurring White Variant in...

The color of Flammulina filiformis is an important commercial trait, and most natural varieties are yellow. This study focused on a natural white variant strain (CN-01) and a yellow strain (JSH17) of F. filiformis. We conducted physiological index measurement and untargeted metabolomics analysis to systematically evaluate its nutritional quality and preliminarily investigate the metabolic differences associated with its white phenotype. The results showed that the total free amino acid content and sweetness intensity of strain CN-01 were superior to those of strain JSH17, although its bioactive components were comparatively lower. Metabolomics analysis revealed that the differential metabolites between the two strains were predominantly enriched in pathways related to amino acid metabolism, energy metabolism, fatty acid metabolism, and glutathione metabolism. Notably, the aromatic amino acid biosynthesis pathway, which is closely associated with pigment synthesis, was not significantly activated in the white strain, likely serving as the key metabolic reason for the formation of its white phenotype. This study provides a scientific basis for resource evaluation and utilization of natural white F. filiformis and elucidates the biochemical mechanisms underlying its color variation from a metabolic perspective.