Comparison Of Microbial Community Structure Characteristics Between Moss Crust And Soil Crust And Subsoil In Different Succession Stages In The Kubuqi Desert

Soil crust is an important part of desert ecosystem,and microorganisms are the main driving force for the formation and development of soil crust,which play an indispensable role in soil crust.In this paper,q PCR and high-throughput sequencing techniques were used to study the microbial communities structure characteristics of moss crusts and soil crusts(physical crusts,algae crusts)and subsoil in different succession stages in Kubuqi Desert,Inner Mongolia.The main conclusions are as follows:(1)With the development of crusts,the content of soil organic matter,total nitrogen,available nitrogen,and total phosphorus reached the highest in moss crusts,indicating that moss plants can effectively improve soil nutrient content.The absolute abundance of bacterial communities in moss crusts and soil crusts and subsoil microbial communities at other different succession stages was the highest,and the absolute abundance of bacterial communities in moss crusts was significantly higher than that in subsoil.The absolute abundance of diazotrophic communities was the highest in algal crusts.The absolute abundance of archaeal communities was the highest in physical crusts,and the absolute abundance of archaeal communities in the subsoil was significantly higher than that in moss crusts.The absolute abundance of fungal communities gradually decreased with the succession of crusts.(2)During the succession process,the composition of bacterial communities was significantly different.Cyanobacteria had the highest relative abundance in physical crusts,and the dominant genera in physical crusts included norank＿f＿＿Chroococcidiopsaceae,etc.Proteobacteria had the highest relative abundance in algal crusts,and the dominant genera in algal crusts were Rubellimicrobium,etc.Actinobacteria had the highest relative abundance in moss crusts,and the dominant genera in moss crusts were Microvirga,etc.The relative abundance of Actinobacteria in the subsoil was higher than that of moss crusts,and the dominant genus in the subsoil was Rubrobacter,etc.The relative abundance of Proteobacteria in the diazotrophic communities was the highest in the physical crust,and the relative abundance of Cyanobacteria was the highest in the algal crust.The dominant genus in the three crusts was Skermanella,and the relative abundance gradually decreased with the succession of crusts.Compared with moss crusts,the relative abundance of Proteobacteria in the subsoil increased,while the relative abundance of Cyanobacteria decreased significantly.The dominant genus in the subsoil was Azohydromonas,etc.The relative abundance of Crenarchaeota was the highest in the three crusts,and the dominant genus was Candidatus＿Nitrocosmicus.The relative abundance of Crenarchaeota was also the highest in the subsoil,and the dominant genera in the subsoil were norank＿f＿＿Nitrososphaeraceae.The relative abundance of Ascomycota in the fungal communities was the highest in the three crusts,and the relative abundance gradually increased.The dominant genera in the physical crust include Cladosporium,the dominant genus in algal crusts was unclassified＿p＿＿Ascomycota.The dominant genera in moss crusts are Octosporella and so on.The relative abundance of SAR＿k＿＿norank in subsoil was the highest,and the dominant genus in subsoil was Gregarina et al.(3)Through co-occurrence network analysis,it was found that the key groups in the early and middle stages of succession(physical crusts,algae crusts)in bacterial communities were more complex.In moss crusts,they were transformed into multiple genera of Acidobacteria,and in subsoil,they were transformed into multiple genera of Actinobacteria.The key groups of algae crusts in the diazotrophic communities were unclassified＿f＿＿Nostocaceae and Nostoc of Cyanobacteria.The key nitrogen-fixing groups in physical crusts,moss crusts and subsoil belonged to Proteobacteria,mainly Skomanella and Azohydromonas.The unclassified＿f＿＿Nitrososphaeraceae or unclassified＿k＿＿norank＿d＿＿Archaea was the key group in the archaeal communities of moss crusts and other soil crusts at different succession stages,and the key archaeal group in subsoil was transformed from unclassified＿k＿＿norank＿d＿＿Archaea to the nitrosative genus of Candidatus＿Nitrocosmicus.The key fungi in the fungal communities of moss crusts and other soil crusts at different succession stages were Ascomycota,and the key fungi in subsoil changed from multiple genera of Ascomycota to multiple genera of SAR supergroup(norank＿c＿＿Glissomonadida,Nudifila).In summary,this paper provides basic data and theoretical support for the study of artificial moss crust desert ecological management.