The Predominant Bacterium Group Analysis Of Saline Soil And The Polyphasic Taxonomy Study Of Strains Q1U~T、Q1R~T And BZ1~T

This paper firstly introduced the overview of taxonomic study of bacteria and introduced the progress in the study of the taxonomy of the genera Halomonas,Prolinoborus and Bacillus. Selective isolation for bacteria in soil samples collected from Inner Mongolia and Qinghai was studied, the strains isolated from the samples were researched using 16 S r RNA gene sequence, and the predominant bacterium group and polyphasic taxonomy were also studied.Different selective media were used for isolation, and 16 S r RNA gene sequences were amplified and analyzed for the determination of phylogenetic relationships. Phylogenetic analysis based on 16 S r RNA gene sequences revealed that the culturable bacteria are very rich in the saline-alkaline soils, 40 representative strains were classified into 15 genera, 12 families and three phyla(Firmicutes, Actinobacteria and Proteobacteria) in the Domain Bacteria. The genus Bacillus is the predominant genus.Three strains, designed Q1 UT, Q1 RT and BZ1 T, showed 16 S r RNA gene sequence similarities of 98.34 %, 97.95 % and 98.28 % to their most closely related species,respectively. As a result, the three strains were estimated as new species and subjected to polyphasic studies. Strain Q1 UT was aerobic, Gram-negative and rod-shaped, its colonies were yellow, it was found to grow at Na Cl concentrations of 0-20 % w/v(optimum 7.5 %w/v), temperatures of 2-37 ℃(optimum 30-33 ℃) and p H 6.0-9.0(optimum p H 7.0), the major ubiquinone was Q-9. Strain Q1 RT was Gram-negative, its colonies were milk-white,it was found to grow at Na Cl concentrations of 0-9 % w/v(optimum 2.5 % w/v),temperatures of 2-38 ℃(optimum 30 ℃) and p H 5.0-9.0(optimum p H 8.0). Strain BZ1 T was Gram-positive, aerobic and rod-shaped, its colonies were yellow, it was found to grow at Na Cl concentrations of 0-5.5 % w/v(optimum 0.5 % w/v), temperatures of 6-40 ℃(optimum 30-33 ℃) and p H 6.0-9.0(optimum p H 7.0), the predominant menaquinone was MK-7, the major fatty acids were iso-C15:0、anteiso-C15:0 and iso-C14:0, the polar lipid acids were DPG, PE and PG.Based on the results of morphological characteristics, physiological and biochemical characteristics, chemical analysis and molecular systematics study, it was proved that thesethree strains represented novel species. The name Halomonas lutescens sp. nov. was proposed for strain Q1 UT, the name Prolinoborus albatus sp. nov. was proposed for strain Q1 RT, the name Bacillus depressus sp. nov. was proposed for strain BZ1 T.