Feather-Induced Enrichment of Onygenales Triggers Cross-Kingdom Functional Shifts in Soil Fungal Communities

As typical urban green spaces with high human activity, hospital green soils not only serve as important microbial reservoirs but may also be associated with potential ecological impacts and public-health concerns. However, the ecological distribution patterns and potential pathogenic functional responses of keratinophilic fungi in these soils remain poorly understood. In this study, green space soils from hospitals in 30 cities across 10 provinces in southern China were examined. Using a feather enrichment treatment combined with Illumina MiSeq high-throughput sequencing, the effects of feather addition (simulating exogenous keratin inputs) on fungal community composition, diversity, and function were analyzed. The results revealed that feather enrichment significantly altered fungal community structure. The relative abundance of Ascomycota increased from 50.74% (control) to 97.19% (treatment group), with Onygenales becoming the dominant fungal order (93.72%), indicating a substantial community shift. Additionally, alpha diversity of the soil fungal community decreased. Functionally, the Pathotroph-Saprotroph trophic mode was significantly enriched, and Plant Pathogen-Undefined Saprotroph emerged as the dominant functional guild. Soil pH and carbon-to-nitrogen ratio (C/N) were identified as key environmental factors associated with community shifts, exhibiting strong negative correlations with both Onygenales and the Pathotroph-Saprotroph functional mode (P < 0.01). This study demonstrates that feather enrichment imposes keratin-based selective pressure, specifically enriching keratinophilic fungal taxa while reshaping soil fungal structure and function. These findings deepen our understanding of how keratin-rich inputs reshape fungal communities in hospital green spaces and provide important insights for the ecological risk assessment of soil microbial communities.