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.

蒙古白环蘑（Leucocalocybe mongolica）是中国内蒙古温带草原特有的、兼具重要文化价值的食用真菌，常形成具有明显植被分带的可见蘑菇圈（fairy ring）。然而其对土壤真菌群落、养分循环及植物生长的生态效应尚未得到充分阐明。
本研究选取6个典型蘑菇圈开展研究，采用高通量测序（High-throughput sequencing）技术分析了内环区域（IA）、出菇区域（FA）及外环区域（OA）的土壤真菌群落组成，并测定了土壤理化性质、酶活性与植物生长指标，以评估其生态功能。
结果显示，出菇区域的真菌α多样性显著低于内环与外环区域；出菇区域以担子菌门（Basidiomycota）为优势类群，其中蒙古白环蘑为核心类群；该区域土壤偏酸性，铵态氮、硝态氮、纤维素酶及漆酶含量显著更高。与之相对，内环与外环区域土壤的几丁质酶、蔗糖酶活性及土壤含水量更高。
网络分析结果表明，出菇区域的真菌群落网络结构最为简单，以蒙古白环蘑为主导；而外环区域的真菌网络结构最为复杂且稳定。
接种实验证实，蒙古白环蘑及其伴生真菌哈茨木霉（Trichoderma harzianum）可显著提升羊草（Leymus chinensis）的株高、地上生物量、光合速率及叶绿素含量。
本研究结果表明，蒙古白环蘑蘑菇圈的中心区域是氮循环与促植物生长的核心功能区；蘑菇圈通过重塑土壤环境与真菌群落结构，形成了“高效核心-多样外围”的空间格局。该研究为提升草原土壤肥力及退化草地修复提供了新的科学参考与研究思路。