Physiological and biochemical changes and microbial community succession during the postharvest rot process of Stropharia rugosoannulata

This study systematically elucidated the microbial community succession and functional gene dynamics during the postharvest spoilage process of Stropharia rugosoannulata by integrating physiological and biochemical indicators with metagenomic analysis. The experimental results demonstrated that as storage time extended, the activities of antioxidant enzymes (superoxide dismutase, peroxidase) in S. rugosoannulata significantly declined, while the content of membrane lipid peroxidation product malondialdehyde increased, leading to compromised cell membrane integrity and creating favorable conditions for microbial colonization. Metagenomic analysis revealed that during the spoilage phase (post-harvest day 14), the relative abundance of Pseudomonadota increased to 85.7%, with Pseudomonas replacing Ewingella as the absolutely dominant microbial population. Further functional gene analysis showed that the post-harvest day 14 exhibited significant enrichment of glycosyltransferases (GT0, GT1, GT2, GT4) and carbohydrate-binding modules (CBM10, CBM16, CBM50), along with pectinase (GH78), chitinase (GH19), and polysaccharide-modifying enzymes (CE4, CE11). This indicated a metabolic shift towards cell wall synthesis and substrate recognition. In contrast, the post-harvest day 7, prior to fruiting body softening, demonstrated high expression of glycoside hydrolases (GH1, GH2, GH4, GH94) and carbohydrate esterase CE8, focusing on the degradation of cellulose and starch. These findings, for the first time from a molecular ecology perspective, clarify that the essence of postharvest spoilage in S. rugosoannulata is a quality deterioration process driven by a Pseudomonas-dominated microbial community. The study provided a basis for the development of targeted antibacterial preservation strategies.