Abstract: In this study, PacBio sequencing technology was utilized to perform high-throughput sequencing of bacterial DNA from the mycelial, surrounding, and control soils ofOphiocordyceps sinensis. The alpha- and beta-diversity of the bacterial community were analyzed, and the molecular ecological network and key microorganisms were identified, and their ecological functions were predicted by FAPROTAX. Analysis revealed that the number of bacterial OTU and species richness (ACE, Chao1) in the mycelial soil were significantly higher than those in control and surrounding soils. In terms of species composition, Acidobacteria was the dominant phylum in both the control and surrounding soils (31.0% and 36.5%, respectively), and the dominant phylum in the mycelial soil was Proteobacteria (36.1%). Molecular ecological network analysis showed that the control soil network exhibited higher complexity. In contrast, the networks of the surrounding and mycelial soils showed lower connectivity but stronger positive correlations among bacterial. A total of 15 key microorganisms were identified across the three bacterial networks, with the least number of key microorganisms in the control soil (20.0%) and the most in the surrounding soil (46.7%). FAPROTAX functional prediction showed that soils with different ecological niches exhibited different ecological functions. The ureolysis, nitrate reduction, fermentation, and phototrophy functional abundances were significantly higher in the mycelial soil compared to the control soil (P<0.05). The abundances of fermentation, nitrate reduction, and phototrophy functions were significantly higher in the mycelial soil than in the surrounding soil (P<0.05). In conclusion, the diversity, composition, and structure of soil bacterial communities in different ecological niches ofO. sinensiswere significantly different, reflecting the screening and filtering effect ofO. sinensison soil bacterial communities. These findings provided foundational data for further research on the mechanisms ofO. sinensisoccurrence and for optimizing its artificial cultivation, with significant technical support implications for poverty alleviation in Tibetan regions.

Key words: Ophiocordyceps sinensis, soil microorganisms, bacterial communities, molecular ecological networks, microbial functions