| 1,In this study, we attempted to analyze culturable-bacteria diversity from soil in natural Populus Euphratica forest in Shaya county of Xinjiang. Through conventional dilution-plating method, we isolated 69 pure cultivable strains. Among them 40 strains were gram-positive, 29 strains were gram-negative, and 18 strains were coccus, 51 strains were rod-shaped. The phenotypic properties, biochemical characterization, 16S rRNA gene sequence analysis and phylogenetic analyses showed that 69 strains belonged to Firmicutes, Actinobacteria, Gamma- proteobacteria and CFB (Cytophaga-Flexibacter-Bacteroides),respectively. Among them 32 strains belonged to Firmicutes (46.4%), including genus of Bacillus and Planococcus; 18 strains belonged to Actinobacteria (26.1%), including genus of Arthrobacter, Kocuria, Leucobacter, Citricoccus and Promicromonospora; 17 strains belonged to Gamma-proteobacteria (24.6%), including genus of Pseudomonas and Psychrobacter; 2 strains belonged to CFB (2.9%), the genus of Sphingobacterium. All of the strains were allocated into 10 genera and 31 OTUs. Bacillus (33.3%) was predominant. The biological diversity index displayed that Simpson diversity index D was 0.7929, Shannon-Wiener diversity index H was 0.7821 and Shannon-Wiener uniformity index E was 0.7821. The data showed that there was a high diversity of bacteria. Most of these isolates could grew under extreme drouthy conditions, identical with the environment of Populus Euphratica forest.2,Strains HS39 was characterized using a polyphasic approach. The results were as follows: cells are Gram-staining-negative, non-motile, non-spore-forming, strictl y aerobic rods, 1.0-1.5μm in length and 0.6-0.8μm in diameter. After 2 days of incubation on LB agar, colonies are 1.0-2.0 mm in diameter, yellow, convex, circular and smooth with entire margins. Growth occurs between 10 and 40℃; the optimum temperature for growth is 30-37℃. The pH range for growth is 5.5-9.0, with an optimum between pH 6.5 and 8.0. Growth occurs in the presence of 0-5 % (w/v) NaCl. Optimum NaCl concentration for growth is 0-3%. Strains HS39 are positive for catalase and oxidase activities, assimilation of D-glucose, N-acetylglucosamine, D-saccharose, D-maltose and salicin. Analysis of the 16S rRNA gene sequence of strain HS39T revealed that it is a member of the genus Sphingobacterium. Sphingobacterium mizutaii ATCC 33299T was the nearest relative (94.0% 16S rRNA gene sequence similarity). The G+C content of the genomic DNA was 40.2 mol%. The major fatty acids were iso-C15:0, iso-C17:0 3-OH and summed feature 3 (comprising C16:1ω6c and/or C16:1ω7c). The predominant isoprenoid quinone was MK-7. On the basis of phenotypic properties and phylogenetic inference, strain HS39T represents a novel species of the genus Sphingobacterium, for which the name Sphingobacterium shayense is proposed. The type strain is HS39T (= CCTCC AB 209006T = NRRL B-59203T). |
