Spatial Variation in Mycosphere Soil Bacterial Communities of Leucopaxillus giganteus and Its Environmental Drivers in Shanxi, China

Leucopaxillus giganteus, a wild saprotrophic fungus with high edible and medicinal value, has not yet achieved large-scale artificial cultivation. To elucidate the abiotic and biotic factors governing its growth, we analyzed physicochemical properties and bacterial communities of mycosphere and bulk soils from Shanxi Province, China. We observed geographic variation in the diversity, composition, and functional profiles of dominant mycosphere soil bacterial communities. Soil organic carbon, available potassium, altitude, longitude, and latitude were the key factors affecting mycosphere soil bacterial community structure. Distance–decay analysis revealed that the beta diversity of mycosphere soil bacterial communities declined with increasing geographical distance. Bacterial diversity in the L. giganteus mycosphere was significantly lower than that in bulk soil. Genera such as Micromonospora, Streptosporangium, Paraburkholderia, Pedobacter, Caballeronia, Paenibacillus, and Flavobacterium could act as saprotrophic helper bacteria in the mycosphere of L. giganteus. LEfSe analysis revealed 72 genera that exhibited significant abundance differences among samples from six geographic regions, including Bradyrhizobium, Sphingomicrobium, and Phyllobacterium. Functional annotation detected enriched pathways for transport and catabolism, signal transduction, and carbohydrate and lipid metabolism in mycosphere soil bacterial communities. These results advance our understanding of the ecological interactions of L. giganteus and support its artificial cultivation and sustainable resource use.