Communities Of Ectomycorrhizal Fungi Associated With Several Common Tree Species In Qilian Mountains

Ectomycorrhizal(ECM)fungi are plant root symbiotic microorganisms that profoundly impact and regulate various ecological processes,such as nutrient acquisition,plant population dynamics,and carbon,nitrogen and phosphorus cycles.It is well known that the community structure of ECM fungi could be influenced by multiple biotic and abiotic factors;however,which environmental factors primarily affect ECM fungi in some specific habitats? whether they exhibit significant host preference? These questions require further investigation.The Qilian mountains are very fragile due to high altitude,and much attentions have been paid for ecological protection and restoration in this region.In this study,several common tree species in the Qilian mountains,including Picea crassifolia from different regions,and Pinus tabuliformis,Populus davidiana,Picea wilsonii and Betula albosinensis in a same habitat,were selected as target tree species.The ECM fungal communities of each tree species were analyzed using high-throughput sequencing technology.In addition,we analyzed environmental factors,such as soil chemical properties and climatic factors.This study aimed to explore the influences of environmental factors and host plant identity(tree species)on ECM fungal communities.The research results are presented below.(1)A total of 394 ECM species(OTUs),belonging to 4 orders and 8 genera,were identified from the roots of Picea crassifolia that were collected from six sites at a large scale.Among them,the dominant genus was Sebacina(relative abundance was 44.8%),and the dominant species was Sebacina epigaea(12.8%).The species richness of ECM fungi varied among sampling sites,and the best predictor was soil p H(which had a significant positive correlation with species richness).The species composition of ECM fungal community also differed among sites,and it was mainly regulated by soil p H and soil carbon-nitrogen ratio.In addition,the community similarity of ECM fungi between samples correlated negatively with the distance between sites,showing a clear phenomenon of distance decay.(2)A total of 271 ECM fungal OTUs,belonging to 7 orders and 19 genera,were identified from the roots of Pinus tabuliformis,Populus davidiana,Picea wilsonii and Betula albosinensis that were collected from a same habitat.The most dominant ECM fungal genus in the roots of Pinus tabuliformis,Populus davidiana and Picea wilsonii was Sebacina,while Cortinarius was the dominant ECM fungal genus for Betula albosinensis.The most dominant ECM fungal species in the roots of Pinus tabuliformis was Sebacina cystidiata(20.1%),and that of Populus davidiana was Sebacina sp.(10.3%),while Cenococcum sp.was the most dominant fungi for both Picea wilsonii and Betula albosinensis(11.5% and 22.1%,separately).Only 19 OTUs were shared among the four tree species,while up to 30% of OTUs were unique for each tree species.The ECM fungal community composition differed significantly among different tree species.These results suggest that ECM fungi exhibit significant host preference.The above results indicate that the Qilian mountains have a high biodiversity of ECM fungi,but the diversity of Picea crassifolia is higher than that of Pinus tabuliformis,Populus davidiana,Picea wilsonii and Betula albosinensis.Soil p H and host plant identity(tree species)are key factors that determine the diversity and community composition of ECM fungi in this region.This study can facilitate our understanding of the community assembly of ECM fungi,and can also provide theoretical guidance and technical supports for biodiversity conservation,fungal resource exploration,and forest restoration in the region of Qilian Mountains.