title: [Genetic diversity of rhizobial bacteria nodulating Tibetia himalaica in eastern Qinghai-Tibet plateau].
abstract: OBJECTIVE
  Genetic diversity of the rhizobial bacteria nodulating Tibetia himalaica in the eastern part of Qinghai-Tibet Plateau (Ganzi State, Sichuan) were evaluated.
  
  
  METHODS
  The pure culture method was used for isolating the rhiobial strains from the nodules. BOXAIR, 16S rDNA sequences, 16S rDNA PCR-RFLP and Principal Component Analysis (PCA) were used to determine the genetic diversity and phylogenetic relationships. The growth in different salt contents, pH and temperatures were tested.
  
  
  RESULTS
  In total 22 strains were isolated from 12 samples in 8 counties. The strains tested were classified into 4 clusters in 16S rDNA PCR-RFLP, and 8 clusters were formed in BOXAIR. The 16S rDNA Simpson genetic diversity index was D = 0. 872. The strains tested were closely related to Rhizobium (11/22 strains), Mesorhizobium (4/22 strains) and Rhizobium- Agrobacterium (7/22 strains). All strains could regularly grow in YMA medium amended with 1% NaCl, and 15/22 strains could grow in 4% NaCl. SCAU679, SCAU694 and SCAU706 could adapt to 7% NaCl, while SCAU689 could tolerant 8% NaCl. Among the strains tested, 15 strains could grow in the pH range from 4.0 to 11; 16 isolates grew well from 4 to 45 degrees C, and all of 22 strains could grow at 28 degrees C after treatment at 60 degrees C for 10 min.
  
  
  CONCLUSIONS
  This study revealed the high genetic diversity of the rhizobia isolated from Tibetia himalaica in the eastern part of Qinghai-Tibet Plateau. The strains tested were adapted to high salt, different range of temperatures and pH.
authors.affiliation: Department of Microbiology, College of Resource and Environmental Sciences, Sichuan Agricultural University, Chengdu 611130, China. jianghm06@163.com
authors.forename: Huaming
authors.initials: H
authors.lastname: Jiang
authors.forename: Ke
authors.initials: K
authors.lastname: Zhao
authors.forename: Songqing
authors.initials: S
authors.lastname: Liu
authors.forename: Xinchun
authors.initials: X
authors.lastname: Liu
authors.forename: Renquan
authors.initials: R
authors.lastname: Li
authors.forename: Wanren
authors.initials: W
authors.lastname: Peng
authors.forename: Bo
authors.initials: B
authors.lastname: Zhang
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Zhang
mesh_terms: D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D007887:Fabaceae / Q000382:microbiology*; D014644:Genetic Variation; D008969:Molecular Sequence Data; D010802:Phylogeny; D053204:Root Nodules, Plant / Q000382:microbiology*; D012988:Soil Microbiology; D018609:Tibet