Fungal Community Composition And Maintenance Mechanism Of Ectomycorrhizal Of Three Herbaceous Plants In Central Inner Mongolia

Ectomycorrhizal(EM)fungi is mutualistic symbionts formed between host plant and soil fungi,which play an important role in plant growth and development,environment adaptation and energy interaction.Carex pediformis,Polygonum divaricatum,Carex yinshanica,as the dominant herbs in the subalpine region of Inner Mongolia,plays an important role in maintaining subalpine ecosystems and maintaining biodiversity.There are abundant and unique mycorrhizal fungi in special habitats in the subalpine region of central Inner Mongolia.However,the research on the EM root fungi(including EM fungi and non-EM fungi)of C.pediformis,P.divaricatum and C.yinshanensis has not been reported yet.Therefore,in this study,C.pediformis,P.divaricatum and C.yinshanensis in the subalpine(Jiufeng and Chunkun)areas of central Inner Mongolia were taken as the research objects.The internal transcribed spacer 2(ITS2)of fungal r RNA in EM roots was sequenced by highthroughput sequencing technology,and the fungal community composition and maintenance mechanism of EM roots were analyzed.The main research results are as follows:(1)Two types of EM have been found in the subalpine region,namely "dauciform" root and linear root.Among them,the most abundant mycorrhizal types of C.pediformis are "dauciform" root types,with 15 and 12 species respectively in the two regions,and the most typical linear root types,9 and 3 species respectively;In P.divaricatum,there are 6 and 1 "dauciform" root types,and 2 and 1 Linear root types,respectively;No "dauciform" root was found in C.yinshanensis,but only one kind of linear root with no obvious infection.(2)By analyzing the diversity and community composition of EM fungi in subalpine areas,it is concluded that on the whole,there are a few dominant evolutionary lineages and a large number of rare evolutionary lineages /Tomentella?Thelephora and/tricholoma are the dominant evolutionary branches shared by the two regions.The species diversity and community composition of EM fungi in different host plants and sampling sites were significantly different.The composition of EM fungal community is mainly restricted by soil conditions on the local scale,while on the regional scale,it is mainly affected by climatic factors.Both deterministic and stochastic processes participated in the composition of herbaceous EM fungal communities in the subalpine region of central Inner Mongolia,and were strongly affected by ecological drift in the stochastic process.(3)For the non-EM fungi,the distribution of non-EM fungi is a few dominant classes and a large number of rare classes;Leotiomycetes,dothideomycetes and sordariomycetes are the dominant classes shared by the two regions,most of which belong to saprophytic fungi and pathogenic fungi.In the ? diversity analysis,there was no significant difference in the diversity of non-EM fungi in Jiufeng Mountain,but there was significant difference in the diversity of non-EM fungi in Chunkun mountain.?diversity analysis showed that there were significant differences in the composition of non-EM fungal communities among the three herbaceous plants in Jiufeng Mountain.The NMDS ranking analysis based on envfit test showed that soil factors were the most important factors affecting the composition of non-EM fungal communities in plant roots.The community assembly is also dominated by both deterministic and stochastic processes,and is also strongly affected by ecological drift in the stochastic process.In this study,EM fungi and non-EM fungi were found in the roots of C.pediformis,P.divaricatum and C.yinshanica in the subalpine meadows of Chunkun Mountain and Jiufeng Mountain in central Inner Mongolia.And analyzed their species diversity,community composition and maintenance mechanism.It provides theoretical basis for vegetation protection and grassland desertification control.