若尔盖高原沼泽土和草甸风沙土细菌16S rDNA PCR-RFLP和系统发育分析

16S rDNA PCR-RFLP analysis and phylogeny of bacteria isolated from swamp and meadow aeolian soils in the Zoige Plateau,Sichuan,China

采用稀释平板法从若尔盖高原沼泽土和草甸风沙土分离获得66株细菌,在16S rDNA PCR-RFLP分析的基础上,测定了22株代表菌株的16S rDNA序列,构建了供试细菌的系统发育关系。16S rDNA PCR-RFLP分析中,在78%相似性水平处,除REG14,REG20,REG22和REG55单独成群外,其余菌株分为8个遗传群,其中,群Ⅰ和群Ⅳ最大,均有15个菌株,其次是群Ⅷ,由11个菌株组成,其余21个菌株分布于5个群内。对22个代表菌株16SrDNA全序列系统发育表明,这些菌株分布于不同的系统发育分支。其中,以芽孢杆菌属(Bacillus)、假单胞菌属(Pseudomonas)和分枝杆菌属(Mycobacterium)为主,其余菌株分布于Lysinibacillus属、中华根瘤菌属(Sinorhizobium)、不动杆菌(Acinetobacter)、固氮菌属(Azotobacter)、红球菌属(Rhodococcus)、微球菌属(Micrococcus)和醋酸杆菌属(Acetobacter)等7个属。

Using the pour plate method,66 bacterial strains were isolated from swamp soil and meadow aeolian soils collected in the Zoige Plateau.The genetic diversity and phylogeny were determined by 16S rDNA PCR-RFLP and 16S rRNA gene sequencing analysis.The result of 16S rDNA PCR-RFLP analysis showed that except for the unique strains REG14,REG20,REG22 and REG55,the other strains were clustered into eight different genetic groups at the similarity of 78%.The largest groups were groupⅠand Ⅳ,each containing 15 bacteria,and group Ⅷ,consisting of 11 strains.16S rRNA gene sequences of 22 representative strains were determined and a phylogenic tree was constructed,the results suggested that these bacteria were mainly distributed in the phylogenetic branches of Bacillus,Pseudomonas and Mycobacterium,whereas the remaining strains belonged to genus Lysinibacillus,Sinorhizobium,Acinetobacer,Azotobacter,Rhodococcus,Micrococcus and Acetobacter;Thus,the genetic diversity among the cultivable bacteria in this region was considerable.