Advancing Industrial Production of White Grifola frondosa: Liquid Inoculum Culture Parameter Optimization and Molecular Insights into Fruiting Body Development

Grifola frondosa is a valuable medicinal and edible mushroom whose industrial cultivation and developmental mechanisms remain poorly understood. In this study, we systematically investigated the optimal cultivation parameters and molecular basis of fruiting body development using the white strain Gr0001+3 through integrated physiological and transcriptomic approaches. The results showed that the optimal liquid medium composition was glucose (28.5 g/L), yeast extract (11.5 g/L), and MgSO4 (2 g/L), with a C/N ratio of 10:1. This composition achieved a mycelial biomass of 2.333 g/L via an orthogonal design. Ideal culture conditions were 100 mL/250 mL liquid volume, 10% inoculum size, and pH 4.0 in single-factor experiments. The fruiting body developmental transcriptomes were analyzed in four stages: early primordia (EP), middle primordia (MP), late primordia (LP), and mature fruiting body (FB). Principal component analysis revealed distinct transcriptional profiles, with greater similarities among later developmental stages. Differential gene expression peaked during the LP vs. FB transition. Functional enrichment (GO/KEGG) showed conserved biological processes in the MP-LP-FB transitions. Heat shock proteins (hsp_78/hsp_82) and the cAMP signaling pathway component (PKAC) were involved in fruiting body development, based on RT-qPCR. This work establishes practical cultivation parameters and offers fundamental insights into the molecular regulation of G. frondosa development, providing a comprehensive foundation for advancing the industrial production of this mushroom.