Integrated enzyme activity and transcriptomic analyses reveal stage-specific lignocellulose utilization in Pleurotus giganteus

The thermotolerant mushroom Pleurotus giganteus is increasingly cultivated in tropical and subtropical regions, where efficient substrate utilization and yield stability are crucial for sustainable production. Understanding stage-specific nutrient utilization is essential for optimizing cultivation substrates, especially when using agricultural residues. In this study, changes in lignocellulose content, enzyme activities, and gene expression were investigated across distinct developmental stages of P. giganteus on a cultivation substrate. Results showed stage-dependent lignocellulose utilization patterns: cellulose and hemicellulose degradation mainly occurred during mycelial growth, while lignin degradation happened throughout the cycle. The enzyme activity patterns matched the changes in lignocellulose content. Neutral xylanase and cellulase activities peaked during mycelial growth and then decreased, while laccase activity fluctuated and reached a maximum during primordium formation. Transcriptomic analysis revealed a stepwise metabolic shift from nutrient acquisition to morphogenesis and post-harvest physiological adjustment. Differentially expressed genes (DEGs) related to UDP-glycosyltransferase activity were consistently upregulated, while those involved in cofactor binding and amino acid metabolism were downregulated. Specifically, the proportion of CAZyme genes was relatively high and increasing. Integrated analysis of enzyme activities and CAZymes identified 45, 22, and 78 genes associated with laccase, neutral xylanase, and cellulase activities, respectively, which may have positive/negative regulation on enzyme activity. Among them, some genes showed high expression and significant differential expression across stages and may be key for lignocellulose degradation and substrate utilization. Overall, this study provides a basis for optimizing cultivation substrates, improving conversion efficiency, and enhancing agricultural residue utilization in P. giganteus production.