Coprinopsis cinerea Enhances Corn Straw Degradation Efficiency in Association with Remodeled Bacterial Communities and Metabolic Pathways

Coprinopsis cinerea (C. cinerea) is a well-recognized model fungus for lignocellulose degradation, yet its microecological mechanism in regulating native microbiota during straw decomposition remains poorly understood. We constructed a physically separated two-layer solid-state microcosm with an upper sterilized corn straw layer and a lower unsterilized field soil layer retaining native bacterial communities, and collected samples on days 15, 30 and 45 post-inoculation for 16S rRNA sequencing, untargeted metabolomics and co-occurrence network analysis. Inoculation did not increase overall bacterial richness and temporarily reduced ASV richness at day 30, but induced marked community structure shifts: enrichment of lignocellulolytic taxa Pseudomonas and Flavobacterium, reduction in Acidobacteriota, and a denser, more synergistic microbial network at the mid-stage. Metabolically, inoculation enhanced early phenylalanine metabolism linked to lignin degradation, and mid- to late-stage ABC transporter, glycolysis/gluconeogenesis and purine metabolism pathways; by day 45, cellulose and hemicellulose degradation rates were 13% and 29% higher in the inoculated group. In conclusion, C. cinerea enhances straw lignocellulose degradation via multi-level microecological remodeling of bacterial communities and metabolic pathways as well as potential direct enzymatic contributions, providing a reference for developing microbiome-modulating fungal inoculants. This study is limited to bacterial responses, with fungal community dynamics uncharacterized.