Abstract:

To provide the basis for the phylogeny of the silicate bacterial strains isolated from the north of China, 48 silicate bacteria obtained together with 3 reference strains were investigated for their morphological characteristics and physiological and biochemical properties. In addition, 43 of the 48 strains were characterized using 16S rDNA-RFLP. The phenotypic and genetic diversity were analyzed by UPMGA (unweighted pair-group method using arithmetic averages). The results were as follows: ①The physiological and biochemical results showed that the NaCl tolerance of the silicate bacteria strains was strong, and the optimum pH value and the maximum tolerated pH of these tested strains were higher than those of the reference strains and those reported in the literature. ②The UPMGA results of phenotypic characteristics demonstrated that 48 tested strains could be divided into 4 groups at 80% similarity and groupⅠcould be divided into 3 sub-groups at 84% similarity. ③The results based on the dendrogram generated by 16S rDNA-PCR-RFLP analysis of 43 tested strains indicated that 8 genetic groups were formed at similarity of 87%. ④The phenotypic and genetic characteristics analysis suggested that most of the silicate strains from different regions and different saline-alkali soils was B. mucilaginosus, and the proportion of B. Mucilaginosus in the 2 analysis methods was 81.25% and 65% respectively. All this revealed the phenotypic and genetic phylogenetic differentiations among the tested silicate bacteria from the saline-alkali soil in the north of China. Also it showed the attribution of the tested bacteria strains in the clustering pattern was closely related to the habitats of saline-alkali soil.