Species Diversity Of Cyanobacteria In Biological Soil Crusts In Gurbantunggut Desert

Biological soil crusts are the "skin" of the desert ecosystem.There are well-developed biological soil crusts(BSCs)in the Gurbantungut Desert.As one of the important microbes of biological soil crusts,cyanobacteria play an important role in improving Soil fertility,windbreak and sand fixation,water conservation,accelerating soil maturation,and promoting the colonization of vascular plants are important ecological functions.Early scholars have done a lot of research on the distribution and ecological functions of cyanobacteria in the Gurbantungut Desert.There are also many studies on the diversity of cyanobacteria based on traditional morphological identification and high-throughput sequencing methods,but with the development of molecular biology,higher resolution and accuracy of cyanobacteria taxonomy needs to be carried out.Therefore,in this experiment,38 cyanobacteria strains were cultured,separated and purified from the biological soil crust of the Gurbantunggut Desert,and the niche,traditional morphological identification,16SrDNA and ITS secondary structure multi-combination method was used to compare the experimental algae.Strains were identified by taxonomy.At the same time,the biological crusts at 5 different sites in the Gurbantunggut Desert were selected to compare and study the differences in the diversity of cyanobacteria and their main environmental impact factors.The main findings are as follows:1)The experimental algae strains belong to Oscillatoriales,Nostocales,Chroococcales and Synechococcales.2)The experimental algae strains in Oscillatoriales belong to the genus Microcoleus,Symplocastrum and Pycnacronema.The identified known species are Microcoleus vaginatus,M.steenstrupii,Symplocastrum californicum,and the unknown species are Microcoleus sp.CXA0202-3,Microcoleus sp.CXA009-3(CXA013-2),Pycnacronema sp.53-3-5B;3)The experimental strains of Nostocales belong to the genus Tolypothrix,Scytonema,and Nostoc.The identified known species are Nostoc indistinguendum,Nostoc commune,Tolypothrix distorta,Tolypothrix campylonemoides,Scytonema hyalinum and Scytonema cf ocellatum;4)The experimental strains of Chroococcales belong to the genus Chroococcidiopsis.The unknown species discovered are Chroococcidiopsis sp.47-8(CXA026-2),Chroococcidiopsis sp.CXA027-1,Chroococcidiopsis sp.57-3-1(CXA029-2);5)The experimental algae strains of Synechococcales should belong to Leptolyngbya,Trichocoleus and Nodosilinea.The identified known species are Leptolyngbya Albertano-Kovacik,Leptolyngbya tenerrima,Trichocoleus desertorum,Nodosilinea epilithica.6)In the Gurbantunggut Desert,different regions affect the species composition and community structure of cyanobacteria.M.vaginatus and M.steenstrupii have obvious advantages in almost every site;in the stage of algal crust and lichen crust,the structure of cyanobacteria community differs or differs significantly between different sites.7)Organic matter,total nitrogen,and crust type are the key factors affecting the community structure of biological crust cyanobacteria in large-scale areas.The results of this study will provide a theoretical basis for in-depth understanding of the diversity and taxonomic status of cyanobacteria in the Gurbantunggut Desert,as well as a scientific basis for the environmental driving factors of cyanobacteria species composition and community structure in a large-scale area.