Soil fungi regulate the response of plant production-community composition relationship to grazing and mowing in a semi-arid steppe

PURPOSE: Soil fungi have been proven to influence the plant productivity and community composition of grasslands, but regulation of soil fungi on the responses of plant production-community composition relationship to grazing and mowing remains unclear. METHODS: Here, we assessed the functional characteristics of three fungal groups using the Ribosomal Database Project (RDP) classifier and data available in FUNGuild, and we characterized the community of saprotrophic, mycorrhizal, and potential plant pathogenic fungi from surface (0–10 cm) and subsurface soils (10–20 cm) of temperate grasslands, which experienced three management practices, grazing, mowing, and grazing + mowing, respectively. RESULTS: We found that all three disturbances decreased plant aboveground production and changed plant community composition in grasslands. Compared with the control, grazing significantly reduced the richness of both saprophytic fungi and potential plant pathogens from surface soil, where the richness of saprophytic fungi under grazing + mowing was also significantly reduced. No changes in the richness of mycorrhizal fungi among three disturbances were observed compared to the control in the surface soil, where antagonistic interaction between potential plant pathogens and saprotrophic fungi drove the plant production-community composition relationship. On the contrary, three disturbances did not change the richness of all fungal functional guilds in the subsurface soil, where the plant production-community composition relationship was driven by antagonistic interaction between mycorrhizal fungi and potential plant pathogens. CONCLUSION: The findings reveal that antagonistic interaction between fungal guilds played important roles in regulating response of plant production-community composition to grazing and mowing in grasslands. Our finding highlights that potential plant pathogens also have a crucial effect on plant production-community composition relationship. This knowledge is important for predicting the shifts in ecosystem functions as consequence of changes in soil fungal groups during grassland management.