盐碱土硅酸盐细菌多样性初步研究

为了给中国北方盐碱地硅酸盐细菌的分类地位提供依据，笔者以3株芽孢杆菌为参照，对分离得到的48株盐碱地硅酸盐细菌进行形态学特征观察、生理生化特性分析，并对其中43个菌株进行16S rDNA限制性酶切片段多样性分析，最后分别用平均连锁法进行聚类分析。结果如下：①生理生化研究结果表明，供试菌株具有较强的NaCl耐受能力，最适pH值和最高pH值耐受能力均高于参照菌株和其他文献报道；②表型特征数值聚类结果表明，供试菌株在80%相似水平上可划分为4个表观群，群Ⅰ在84%的相似水平上又分为3个亚群；③16S rDNA-PCR-RFLP聚类图谱表明，在87%的相似水平上，43个菌株被分成8个遗传群；④表型及遗传多样性2种聚类分析结果均表明，盐碱土中以胶质芽胞杆菌（B. mucilaginosus）为主，分别占81.25%和65%。由此可见，中国北方盐碱土硅酸盐细菌在表型特征和系统发育进化上均呈现多样性，菌株在聚类图谱中的归属与盐碱地生境密切相关。

Preliminary Study on Diversity of Silicate Bacteria from Saline-Alkali Soil

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：（1）The 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.（2）The 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.（3）The 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%.（4）The phenotypic and genetic characteristics analysis suggested that most of the silicate strains from different regions and different saline-alkali soils wasB.mucilaginosus ,and the proportion ofB.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.