Community Structures Of Soil Ectomycorrhizal Fungi In Shrublands Of Four Typical Shrub Species In The Mu Us Desert

As an important compoment of fungi,ectomycorrhizal fungi play an important role in promoting plant growth and improving plant resistance to environmental stress.Previous studies on the structural characteristics and ecological functions of ectomycorrhizal fungi community mainly focused on forest ecosystems.However,in desert ecosystems with harsh environments,the fungal composition,community structure,and influences on plants are largely unexplored.The study investigated ectotrphic mycorrhizal fungal community composition,structure characteristics,and key and indicator species of four desert shrub species Artemisia ordosica,Salix psammophila,Hedysarum mongolicum,and Caragana korshinskii in the Mu Su Desert,using field in-situ sampling and high-throughput sequencing technologies.The main findings are as follows:(1)The ectomycorrhizal fungi of the four shrub species belonged to 2 phylum,2 class,4 order,8 families and 11 genera.Among them,basidiomycetes was the dominant species,and ascomycetes accounted for only 2.79% in the relative abundance.The composition of ectomycorrhizal fungi of four typical shrub species at phylum level showed significant differences among species,but rhizospheric and non-rhizospheric compositions were similar.There were 15 endemic species in the ectomycorrhizal fungal community of S.psammophila,but no endemic species were found in the ectomycorrhizal fungal community of H.mongolicum.The functional prediction showed that the relative abundance of functional genes in ectomycorrhizal fungi of the four shrub species greatly varied between species,but the results were similar between rhizosphere and non-rhizosphere.However,there was no significant difference between rhizospheric soil and bulk soil.(2)The community structure of ectomycorrhizal fungi of C.korshinskii was similar to that in bare sand.The abundance index of ectomycorrhizal fungal of S.psammophila was significantly higher than that of other shrub species,but the evenness index and Simpson diversity index were significantly lower than that of other shrubs.The diversity index of S.psammophila and C.korshinskii were significantly lower than that of H.mongolicum and A.ordosica,but the difference between them was not significant.The Chao1 and ACE indexes of H.mongolicum and A.ordosica were between S.psammophila and C.korshinskii,and were significantly higher than that of C.korshinskii.The structure of rhizospheric and non-rhizospheric ectomycorrhizal fungal communities of the same shrub species were similar.(3)The dominant ectotrophic mycorrhiza fungal genera of A.ordosica,C.korshinskii and H.mongolicum ectotrophic were Cortinarius,Inocybe,Hebeloma and Mallocybe,respectively;while those of C.korshinskii were Geopora,Cortinarius,Hebeloma,Inocybe,Tomentella and Mallocybe.The key species in the ectomycorrhizal fungal community of the four shrub species belonged to Inocybe.The number of indicator species was 15,3,and 2,respectively.No indicator species of ectotrophic mycorrhiza fungi were detected in C.korshinskii.To conclude,this study revealed the community structural characteristics of ectomycorrhizal fungi of the four typical shrub species in the Mu Us Desert,and detected the dominant,key and indicator genera,which is helpful to comprehensively understand the microbial composition of desert ecosystems,and adaptive strategies of desert plants,and to provide theoretical support for vegetation restoration of desert ecosystems.