Isolation And Identification Of Three New Bacteria Including Sphingomonas From Inner Mongolia Grassland Soil

Soil microorganisms are rich in species and quantity resources.The most abundant microbial communities on earth exist,such as bacteria,archaea,fungi,viruses,protozoa and some micro animals.Soil microorganisms are found in almost all phylum,which has important research significance and broad application prospects.Through soil sampling and isolation and identification of soil microorganisms,we can systematically classify and identify the microorganisms that can be cultivated,enrich the types of soil microorganisms,and lay a foundation for the study of the role of soil microorganisms in biogeochemical cycle and ecology.In this paper,bacteria were isolated from three soil samples from Xiwuqi(meadow grassland),Maodeng pasture(typical grassland)and Saihantala(desert grassland)by traditional isolation method,and species classification was performed based on 16 S rRNA gene seqeuncing.In addition,two strains(XHJ-2^T and MHJ-3Q^T)of Sphingomonas and a strain MHJ-10J^T of Pseudomonas were identified as novel species using the multiphase taxonomy.The main results are as follows:1.A total of 136 strains of bacteria were isolated from three type grassland soil samples of Xiwuqi,Maodeng pasture and Saihantala.Baset on 16 S rRNA gene sequence,they belonged to four phyla including Firmicutes,Proteobacteria,Actinobacteria and Bacteroidetes,with 44 genera.The order of population complexity of isolated bacteria was Xiwuqi grassland soil sample > Maodeng pasture soil sample > Saihantala soil sample.2.Classification and identification of Sphingomonas sp.XHJ-2^T and MHJ-3Q^T:Strains XHJ-2^T and MHJ-3Q^T are novel species of genus Sphingomonas of Alphproteobacteria.XHJ-2^T and MHJ-3Q^T cells were gram negative,short rod-shaped and without flagella free.Phylogenetic analysis based on 16 S rRNA gene sequences showed that strain XHJ-2^T and MHJ-3Q^T was most closely related to Sphingomonas zeicaulis 541(97.09%)and Sphingomonas rosea PB196(97.31%),respectively.The genomic DNA G + C contents of XHJ-2^T and MHJ-3Q^T were64.61% and 67.84%,respectively.The main respiratory arousal of XHJ-2^T and MHJ-3Q^T was fanniang-10(Q-10).The major fatty acids of XHJ-2^T were summarized feature 8(C18:1 ?7c and / or C18:1 ?6c)(39.58%)and C16:0(21.75%).The main fatty acids of MHJ-3Q were C15:1 ?5c(34.47%)C15:0 iso(15.71%)and C13:0 iso(11.07%).The main polar lipids of XHJ-2^T were phosphatidyl glycerol(PG),phosphatidyl ethanolamine(PE),an unidentified phospholipid(PL)and an unidentified polar lipid(L).The main polar lipids of strain MHJ-3Q^T were diphosphatidylglycerol(DPG),phosphatidylglycerol(PG),phosphatidyl ethanolamine(PE),a phospholipid with unidentified structure(PL).The type strain,XHJ-2^T(= KCTC 82618 T = CGMCC 17322T)and MHJ-3Q^T(107718T5CGMCC1.12214T).3.Classification and identification of Pseudomonas MHJ-10JT:Strain MHJ-10J^T is novel species of Pseudomonas in Alphaproteobacteria.MHJ-10J^T cells were gram negative,short rod-shaped,with flagella.Phylogenetic analysis based on 16 S rRNA gene sequences showed that strain MHJ-10J^T was most closely related to Pseudomonas lutea OK2T(98.5%).The values of the average nucleotide identities(ANI)between strain MHJ-10J^T and its relatives were all below80.5%.The main respiratory arousal was fanniang-10(Q-10).The mian cellular fatty acids(> 5%)were composed of C16:0(26.39%),summed feature 3(C_18:1 ?6c and/or C_18:1 ?7c,22.22%),summed feature 8(C18:1 ?7c and/or C18:1 ?6c,20.65%),and C17:0cyclo(6.7%).The major components of polar lipids were composed of phosphatidyl ethanolamine(PE),diphosphatidylglycerol(DPG),phosphatidyl glycerol(PG),and a small amount of three unknown phospholipids and two unknown lipids.The genomic DNA GC content of the strain MHJ-10J^T is 64.8 mol%.The type strain of this species is MHJ-10JT(= KCTC 82206 T = CGMCC 17322T).