Biogeographical variation in mycosphere-associated bacterial communities in Leucopaxillus giganteus

Leucopaxillus giganteus is a wild saprotrophic fungus with significant edible and medicinal value in China. Currently, there is a research gap on the biogeographical variation of Leucopaxillus giganteus. To clarify the abiotic and biotic factors influencing its growth, we analyzed the physicochemical properties of mycosphere and bulk soils and associated bacterial communities in Shanxi Province, China. We detected differences in the diversity, structural composition, and functional traits of dominant mycosphere bacterial communities across regions. Soil pH, soil organic carbon, available potassium, and monthly mean temperature were key factors affecting the structure of these communities. Bacterial diversity was significantly reduced in the mycosphere of L. giganteus compared with bulk soil. Genera such as Pseudomonas, Sphingomonas, Mucilaginibacter, and Gemmatimonas may function as saprotrophic helper bacteria in the mycosphere of L. giganteus. The mycosphere soil bacterial communities also showed marked enrichment in functional pathways related to digestive system coordination, immune modulation, membrane transport, nucleotide metabolism, signaling networks, and catabolic processes. These findings provide new insights into the ecological interactions of L. giganteus and have implications for its sustainable utilization, cultivation, and economic benefits.