Geographic Provenances Outweigh Tissue Compartments in Bacteriome Assembly of the Ectomycorrhizal, Edible, and Hallucinogenic if Undercooked, Lanmoa asiatica (Boletaceae, Boletales) Mushroom from Yunnan China.

Ectomycorrhizal fungal sporomes represent complex microuniverses harboring structurally and functionally eclectic microbiomes with significant ecological roles and potential anthropogenic applications. Nevertheless, the factors governing the assembly of these microbial communities remain poorly understood, and numerous fungal taxa, including many ectomycorrhizal species, remain uninvestigated. This study characterizes the bacteriome of the socioculturally and economically important yet hallucinogenic-if-raw ectomycorrhizal bolete Lanmoa asiatica. We analyzed 36 basidiomata from four geographic locations within China, partitioning each into pileus, stipe, and hymenophore tissues, and sequenced the V5-V7 region of the bacterial 16S rRNA gene. Proteobacteria dominated (>85%), with Pantoea, Sphingomonas, and the Burkholderia complex identified as core genera. Contrary to expectations, α-diversity was highest in the stipe (Chao1 index up to 1934) rather than the exposed hymenophore. PERMANOVA indicated that geographic origin (R2 = 0.46, p < 0.001) was a stronger structuring force than tissue type (R2 = 0.28, p < 0.01). Functional prediction via PICRUSt2 revealed enrichments in lipid metabolism, antimicrobial resistance, and apoptosis pathways across sites, while tissue-specific functions involved carbohydrate and nitrogen metabolism. These findings support a hierarchical model of bacteriome assembly where broad-scale environmental filters override micro-niche differentiation, providing a biogeographic framework for the conservation of this highly valued edible mushroom.