Preliminary Study On Resources Of Microbial In Salty Soil Of Qaidam Basin

In this research, we measured the soil physical and chemical properties and microbial quantity determination of salt lake soil of Qaidam basin, isolated culturable microbes and conducted the molecular biological identification and the study of the salt tolerance patterns of the isolates. We got the following conclusions:1. The pH of Qaidam basin salt lake soil is 6.72 to 8.53, which revealed that the soil is neutral or alkaline; the content of organic matter, total N, total P, total K, nitrate nitrogen, Available P, Available K is 1.37-2.96g·kg-1, 0.007-0.722g·kg-1, 0.215-0.904 g·kg-1, 17.59-25.46 g·kg-1, 1.18-5.90 mg·kg-1, 1.37-6.65 mg·kg-1, 35.72-228.29 mg·kg-1, respectively.The microbial biomass of the region I or the region II in Qaidam basin is far lower than that of the region III.2. Among collected soil samples, the No.7 soil sample has the most strain counts and species, and the No.6 sample has the least; considering the previous conclusions, we can conclude that the soil microbial populations of region III are richer than that of the region I or the region II in the Qaidam basin. R2 A medium is the most suitable for the microorganism isolation in this study, and the F5 medium is the secondly. CMKA medium is more suitable for isolating special bacteria. while the CCMS medium is not suitable in this study3. Phylogenetic analysis of the 197 isolates were done base on the sequence of 16 s rDNA. The results indicated that all strains can be divided into 18 genus s and 47 species. Actinomycetes include 7 genus : Prauserella、Kocuria、Actinoalloteichus、Nocardiopsis、Streptomyces and Saccharopolyspora, while bacteria include 11 genus: Staphylococcus、Bacillus、Lentibacillus、Oceanobacillus、Halobacillus、Chromohalobacter、Halomonas and Planococcus 、Corynebacterium、Gracilibacillus and Microbulbifer.4. The results of the salt tolerance test of the 12 chosen actinomycetes showed that 7 of the strains could grow on the medium with no salt and the other 5 strains were halophilic actinomycetes. For the mixed salt,2 strains are mild halotolerant microorganisms, 2 are medium halotolerant, 7 strains are highly halotolerant and 1 strain is extremely halotolerant. For NaCl, 1 strain is mild halotolerant microorganisms, 6 strains are medium halotolerant, 3 strains are highly halotolerant and 2 strains are extremely halotolerant. For MgCl2, 3 strains are mild halotolerant microorganisms, 1 strain is medium halotolerant, 3 strains are highly halotolerant and 5 strains are extremely halotolerant. For CaCl2, 3 strains are mild halotolerant microorganisms and 9 strains are medium halotolerant microorganisms.5. The 16 S rDNA of strain 95 and 173 were sequenced and blasted in the EzBiocloud. The similarity of 16 S rDNA sequence of strain 95 and the most closely related type strain Streptomycessedi 65188(T) is 98.12% and a stable separate lineage was formed in the N-J and M-L phylogenetic tree. The similarity of 16 S rDNA sequence of strain 173 and the most closely related type strain Aliifodinibius roseusYIMD15(T) is 95.10% and a stable separate lineage was formed in the N-J and M-L phylogenetic tree. The results of the morphology observation physiology, biochemistry identification chemical test and molecular analysis suggested that the strain 95 and 173 should be considered to be new speciess.