Community Structure And Diversity Of Microorganism In Biological Soil Crusts And Underneath Soil Of Inner Mongolia Deserts

Desertification is a significant global ecological and environmental problem and its hamful effects are major in China. Inner Mongolia,’riched’ in deserts, is often well known as "Origin of Sandstorm" and where is attracted much attention in desertification control. Biological soil crusts (BSCs) is able to limit further development of desertification and helpful in restoration of deserted soil, making it being important in the desert ecosystem stability, restoration and reconstruction. Microorganism is an important component and plays a key role in the formation and development in BSCs. The study on microbial community will provide evidence for the function of microorganism in the development of BSCs and lay the foundation for the related microbial resources. However, Microorganism community structure and composition in BSCs and underneath soil of Inner Mongolia deserts is remain unknown and conduct the relevant research will be of important theoretical and practical value.Based on Miseq high-throughput sequencing, in this study we anlysis microbial community structure of different types BSCs and their underneath soil in Kubuqi and Maowusu desert at different seasons, and then determined the relathionships between envrinmental features and microbial composition in canonical correspondence analysis (CCA). Results and conclusions are as the followings:(1) Soil physicochemical properties:pH and water content of BSCs was less than the corresponding underneath soil, but organic matter, available nitrogen and chlorophyll content were quite the contrary; in comparasion of the same type samples from the same place, pH of May was higher than September; BSCs available nitrogen content in May was lower than that in September, while available phosphorus and organic matter content was in the opposite; in underneath soil, available nitrogen and available phosphorus conten in May was lower than in September, but organic matter content was in the opposite.(2) Microbial diversity differences are significant in time and space:September samples was higher than May samples; BSCs bacterial diversity is generally higher than the underneath soil, and most BSCs fungal diversity is lower than the underneath soil; Maowusu microbial diversity is higher than Kubuqi.(3) Community structure:12 samples had bacterial OTU number range of 585-1130 in May, they were dominanted by Proteobacteria (9.46% -39.99%), Firmicutes (0.000035% -63.48%), Acidobacteria(0.13% -40.89%), Actinobacteria (4.71% -30.89%), Bacteroidetes (1.92% -27.68%), Chloroflexi (0.19% -7.05%), Cyanobacteria (0.034% -45.54%), Gemmatimonadetes (0.013%-11.53%). Proteobacteria, Cyanobacteria and Bacteroidetes are dominant species in BSCs, Proteobacteria, Acidobacteria and Actinobacteria are dominant species in underneath soil.11 samples had bacterial OTU number range of 4348-7439 in September, they were dominated by Proteobacteria (26.91% -48.86%), Bacteroidetes (2.52%-13.39%), Actinobacteria (7.33% -44.61%), Fusobacteria (0.00% -5.61%), Acidobacteria (7.62% -23.50%), Gemmatimonadetes (1.15% -6.77%), Firmicutes (0.23% -9.35%). Proteobacteria, Actinobacteria,Bacteroidetes and Cyanobacteria are dominant species in BSCs, Proteobacteria, Actinobacteria, Bacteroidetes are dominant species in underneath soil.In September, fungal OTU had 90-417, of which the major failed to classified into known taxa but the others belonged in five known phylum, namely Zygomycota (Zygomycota) (0.00% -9.77%), Basidiomycota (0.00% -30.69%), Glomeromycota (0.00% -0.12%), Chytridiomycota (0.00% -1.6%), Ascomycota (7.28% -50.50%).(4) canonical correspondence nalysis:soil moistureorganic matter, chlorophyll and pH had more effect on the composition of microbial communities while available nitrogen and phosphorus had less effect.