Transcriptomic analysis reveals cell wall polysaccharide metabolism associated with post-harvest softening in shiitake mushrooms (Lentinula edodes)

Shiitake mushrooms ( Lentinula edodes ) undergo rapid softening during postharvest storage, which reduces their texture, quality, and shelf life. To elucidate the underlying mechanisms, we examined cell wall polysaccharide metabolism during storage at 10 ± 0.5 °C. After 12 d, firmness declined markedly, accompanied by decreases in chitin, cellulose, and total cell wall polysaccharides. Meanwhile, activities of cellulase, chitinase, and β-1,3-glucanase increased significantly. Transcriptomic sequencing identified 9139 differentially expressed genes (DEGs): 1672 in W6 d vs W0 d, 3954 in W12 d vs W0 d, and 3513 in W12 d vs W6 d. KEGG enrichment analysis revealed that softening involves diverse pathways, including starch and sucrose metabolism, glycolysis/gluconeogenesis, fructose and mannose metabolism, oxidative phosphorylation, the TCA cycle, autophagy regulation, pyruvate metabolism, pentose and glucuronate interconversions, amino sugar and nucleotide sugar metabolism, galactose metabolism, and biotin metabolism. Several genes encoding cell wall–degrading enzymes were highlighted: one 1,3-β-D-glucosidase, three β-D-glucosidases, one 1,3-β-glucan synthase, one cellulase, one hexokinase, two endo-1,3-β-glucanases, one pyruvate kinase, three chitinases, one chitin synthase, and one chitosanase. These results demonstrate that softening is closely linked to coordinated changes in polysaccharide degradation, enzyme activity, and gene expression, providing new insights into the molecular basis of postharvest textural deterioration in L. edodes .