Mycorrhizal and rhizospheric fungal community assembly differs during subalpine forest restoration on the eastern Qinghai-Tibetan Plateau. Ectomycorrhizal fungi for Abies faxoniana and Betula albosinensis

Background and aims Revealing the relationship between forest trees and their mycorrhizal and rhizospheric fungi is very important in understanding forest community resistance and stability, and ecosystem functioning (e.g., carbon sequestration). However, the community assembly and function of root symbionts and associated fungi during forest restoration are poorly documented on the Tibetan plateau. Methods In this study, we examined the ectomycorrhizal and rhizospheric fungal communities of two dominant tree species (Abies faxoniana and Betula albosinensis) in subalpine forest communities with distinct forest restoration stages (30- vs. 60-year) after clear-cutting, using Illumina MiSeq sequencing of internal transcribed spacer 2 (ITS2) sequences.Results A total of 1222 EM and 5882 rhizospheric fungal operational taxonomic units (OTUs) were obtained at a 97% sequence similarity level, respectively. They were mainly dominated by Basidiomycota. Tree species identity and forest restoration stage had not a significant effect on the OTU richness of both EM and rhizospheric fungi. However, the community assembly of EM and rhizospheric fungi was significantly different during forest restoration, with opposite patterns shown on ectomycorrhizal and rhizospheric fungi. The ectomycorrhizal fungal community assembly was significantly affected by host tree identity, stand age and population dynamic, while the rhizosphere fungal community was significantly structured by combinations of host trees biomass, soil properties and spatial distance.Conclusions Our data provide important insights that community assembly in EM and rhizosphere fungi may respond idiosyncratically during forest restoration on the eastern Qinghai-Tibetan plateau, potentially altering carbon and nutrient cycles in relation to the tree-mycorrhizae-rhizosphere fungus associations.