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武汉大学 (2010)

Study on Diversity of Culturable Bacteria in Xinjiang Desert and Polyphasic Taxonomy Study of Four Novel Species

安红丽;

Titre : Study on Diversity of Culturable Bacteria in Xinjiang Desert and Polyphasic Taxonomy Study of Four Novel Species

Auteur : 安红丽;

Grade : Doctoral Dissertation 2010

Université : 武汉大学

Résumé
Xinjiang is located in northwestern China, the unique climate and geographical conditions result in the novel microbial resources in the area. In this study,404 bacteria isolated and initiatively indentified from samples collected in Xinjiang desert sand, desert sand near plant roots, mining soil and sand samples after exposure to gamma radiation, were belonging to 5 phylum,8 classes,16 orders,37 families and 53 genera. Predominant bacteria belong to Actinobacteria, followed by Firmicutes. Drought-tolerant, few nutrients and radiation-resistant bacteria were the major bacterial groups in this region.12.6% bacteria whose 16S rDNA sequence similarities were less than 97% may be potential new taxa. Date analyses for bacterial diversity of four samples indicated that soil samples showed higher diversity and evenness than the other three samples.In addition, polyphasic taxonomic approach was used to identify strainl0-1-101T, 10-1-84T,13-4-17T, and T104-41T.Strain 10-1-101T, isolated from a sand sample collected from the desert of Xinjiang, China, was a Gram-negative, aerobic, motile, rod-shaped bacterium. Colonies grown on 0.1 x trypticase soy broth agar were circular, convex and light-pink-coloured. Its major cellular fatty acids were C18:1ω7c (72.71%) and C16:0 (7.05%). The DNA G+C content of this strain was 68.8 mol% and Q-10 was the major respiratory quinone. In addition,16S rRNA gene sequence analysis indicated that strain 10-1-101T was related to type strains of the genus Skermanella, with similarities ranging from 92.74% to 94.07%. On the basis of genotypic, phenotypic and phylogenetic data, this strain represents a novel species of the genus Skermanella, for which the name Skermanella xinjiangensis sp. nov. is proposed, with 10-1-101T (=CCTCC AB 207153T=NRRL B-51273T) as type strain.A Gram-negative, aerobic, motile and rod-shaped Sphingomonas-like bacterium, strain 10-1-84T, was isolated from a sand sample collected from the desert of Xinjiang, China, and was subjected to a polyphasic taxonomic approach. The strain contained Q-10 as the major predominant ubiquinone and C18:1ω7c, C16:0, C14:0 2-OH and C 16.1ω7c and/or C 15:0 iso 2-OH as the major fatty acids. The polyamine pattern predominantly contains sym-homospermidine. The main polar lipids were sphingoglycolipid, phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidyldimethylethanolamine and phosphatidylethanolamine. The DNA G+C content of this strain was 63.3 mol%. Levels of 16S rRNA gene sequence similarity between strain 10-1-84T and the type strains of Sphingomonas species ranged from 91.105% to 96.544%. Phylogenetic analysis based on 16S rRNA gene sequence indicated that strain 10-1-84T belonged to the genus Sphingomonas. On the basis of phylogenetic analysis and physiological and biochemical characterization, strain 10-1-84T represents a novel species of the genus Sphingomonas, for which the name Sphingomonas xinjiangensis sp. nov. is proposed, with 10-1-84T (CCTCC AB 208035T=NRRL B-51332T) as type strain.A Gram-positive, rod-shaped, motjiuile and endspore-forming bacterium, designated strain 13-4-17T, was isolated from desert soil sample from xinjiang in China and have been characterized using a polyphasic taxonomy approach.16S rRNA gene sequence analysis showed that strain 13-4-17T belonged to the genus Paenibacillus ; highest sequence similarities were with Paenibacillus chitinolyticus IFO 15660T (93.921%), Paenibacillus thailandensis KCTC 13043 T (93.591%), Paenibacillus pabuli JCM 9074 T (93.557%), Paenibacillus kribbensis AM49T (93.520%). The strain were found to have meso-diaminopimelic acid in the cell-wall peptidoglycan, MK-7 as its predominant menaquinone and anteiso-C15:0 as its major fatty acid. The G+C content of the genomic DNA of the strain 13-4-17T was 53.8 mol%. Based on the physiological, chemotaxonomic and phylogenetic characteristics, strain 13-4-17T was classified as representing a novel species of the genus Paenibaillus, for which the name Paenibacillus deserti sp. nov is proposed. The type strain is 13-4-17T(=CCTCC AB 208034T=KCTC 13238T).Strain T104-41T, which was isolated from a soil sample collected from the xijiang. The organism was coccobacillusshaped, non-motile and formed red-coloured, Gramnegative bacterium colonies on 0.1×trypticase soy broth agar. The respiratory quinine was ubiquinone-10. The major fatty acids were C18:1ω7c and C16:1ω7c and/or C16:1ω6c. The G+C content of the genomic DNA was 71.75 mol%. A comparison of sequences in GenBank revealed that strain T104-41T exhibited highest 16S rRNA gene sequence similarity (91.849-98.007%) with Roseomonas species. DNA-DNA hybridization experiments revealed a low level levels of relatedness between strain T104-41T and the phylogenetically most closely related species Roseomonas vinacea KCTC 22045T (22.96%). Strain T104-41T could be distinguished from all Roseomonas species with validly published names by differences in phenotypic and genotypic properties. In view of the combined phenotypic, chemotaxonomic and phylogenetic data, strain T104-41T should be classified as a representative of a novel species in the genus Roseomonas, Roseomonas xinjiangensis sp. nov. ; the type strain is T104-41T (= CCTCC AB 208251T=NRRL B-59266T).

Mots clés : Xinjiang; Bacterial diversity; Polyphasic taxonomy; Skermanella; Sphingomonas;

Présentation (CNKI)

Page publiée le 19 mai 2018