Fungal Community Dynamics and Growth Promoting Effects on Leymus chinensis in Leucocalocybe mongolica Fairy Rings
Leucocalocybe mongolica is an endemic and culturally important edible mushroom found in the temperate grasslands of Inner Mongolia, China. It often forms visible fairy rings with distinct vegetation zones. However, its ecological impact on soil fungal communities, nutrient cycling, and plant growth is not well understood.In this study, six typical fairy rings were examined. High-throughput sequencing was used to analyze soil fungal communities in three zones: the inner area (IA), the fruiting area (FA), and the outer area (OA). We also measured soil properties, enzyme activities, and plant growth to evaluate ecological functions.Fungal alpha-diversity was significantly lower in the FA than in the IA and OA. The FA was dominated by Basidiomycota, mainly Leucocalocybe. FA soils were more acidic and had higher levels of ammonium, nitrate, cellulase, and laccase. In contrast, IA and OA soils had more chitinase, sucrase, and moisture. Network analysis showed that the FA had the simplest fungal network structure, dominated by Leucocalocybe, while the OA had the most complex and stable network.Inoculation tests showed that L. mongolica and its associated fungus Trichoderma harzianum significantly improved plant height, aboveground biomass, photosynthetic rate, and chlorophyll content in the grass Leymus chinensis.These results suggest that the center of L. mongolica fairy rings acts as a core area for nitrogen cycling and plant growth promotion. The fairy ring creates a "high-efficiency center--diverse periphery" spatial pattern by reshaping the soil environment and fungal community structure. This study offers new insights for enhancing grassland soil fertility and restoring degraded land.