Host phylogeny is the primary determinant of ectomycorrhizal fungal community composition in the permafrost ecosystem of eastern Siberia at a regional scale

Ectomycorrhizal (EM) fungal communities have been studied worldwide; however, those in the very cold and dry continental climate zone of northern Eurasia remain understudied. We investigated EM fungal community structure on plant roots and its determinants in eastern Siberia. We identified 291 EM fungal taxa belonging to 37 fungal genera from nine sites spanning 2100 km. In a variation partitioning analysis, host plant phylogeny was the primary factor that explained variation in fungal community composition, followed by spatial distance, soil, and climate. Host specificity and preference were attributed to differences in EM fungal community composition among host plants. The EM fungal community on Larix cajanderi, the dominant canopy tree in the region, was characterized by a high proportion of Suillus and Rhizopogon species. This implies that these specialist fungal symbionts have a close ecological relationship with pioneer Larix trees to adapt to the harsh continental climate of Siberia.

Automated summary

EM fungal communities on plant roots in eastern Siberia are primarily influenced by host plant phylogeny, followed by spatial distance, soil, and climate. The dominant canopy tree Larix cajanderi harbors a high proportion of Suillus and Rhizopogon species in its root system, indicating a close ecological relationship between these specialist fungal symbionts and the pioneer Larix trees in adapting to the harsh continental climate of Siberia.