Transcriptome Analysis of Postharvest Lentinula edodes Cell Wall Metabolism During Storage Indicating a Laccase-Mediated Regulatory Network

Postharvest <i>Lentinula edodes</i> (shiitake mushroom) undergoes rapid textural deterioration, which is primarily driven by complex cell wall remodeling. This study investigates the physiological and transcriptomic changes in <i>L. edodes</i> during storage at 4 °C for 8 days. Results showed that cellulose content significantly decreased, while chitin and β-glucan levels exhibited anomalous increases, accompanied by a surge in the activities of cellulase, chitinase, and β-1,3-glucanase. Concurrently, intensifying membrane lipid peroxidation and an imbalance in reactive oxygen species (ROS) homeostasis were observed. Transcriptomic analysis identified 2204 and 1808 differentially expressed genes (DEGs) at the middle (4 d) and late (8 d) storage stages, respectively. Partial Least Squares Regression (PLSR) identified a core module of nine key regulatory genes (VIP > 1.0), including β-glucanase, laccase, and catalase, which significantly contributed to the physiological shifts. The results suggest that an upstream ROS imbalance may contribute to the dysregulation of midstream laccases, potentially reducing the oxidative cross-linking of phenolic components and loosening the cell wall matrix. These alterations may increase the accessibility of structural polysaccharides to downstream cell wall-degrading enzymes, which could contribute to structural collapse, although functional validation is required to establish causality. These findings provide a gene-level framework for understanding postharvest edible fungi physiology.