松嫩平原盐碱地中耐(嗜)盐菌的生物多样性

Biodiversity of culturable halotolerant and halophilic bacteria isolated from saline-alkaline soils in Songnen Plain

【目的】分离纯化松嫩平原盐碱地中可培养的耐盐菌和嗜盐菌,并分析其生物多样性。【方法】采用纯培养法和定向富集法从该地区盐碱土样中分离耐盐菌和嗜盐菌,然后通过16S rRNA基因同源性比对鉴定所分离细菌的系统发育学地位,从而获取松嫩平原盐碱地中耐盐菌和嗜盐菌的多样性信息。【结果】共分离到细菌40株,分属于细菌域中3个门(Actinobacteria,Firmicutes,γ-Proteobacteria)、8个科、16个属、34个种。其中多数菌株属于厚壁菌门(Firmicutes),最优势属为葡球菌属(Staphylococcus)(8株,占总菌株的20%),其次依次为盐单胞菌属(Halomonas)(5株,12.5%)、芽胞杆菌属(Bacillus)(4株,10%)、大洋芽胞杆菌属(Oceanbacillus)(4株,10%)、库克菌属(Kocuria)(4株,10%)和假单胞菌属(Pseudomonas)(3株,7.5%)等。其中9株细菌的16S rRNA基因序列与最近缘种的同源性在97.2%-99.0%之间,可能为新种。菌株耐盐能力主要在5%-10%之间,其中62.5%的菌株为耐盐菌,其余则为中度嗜盐菌。所有菌株的耐碱能力在pH 9-12之间,其中60%的菌株耐碱能力则高达pH 12,除两株为嗜碱菌,其余均为耐碱菌。【结论】研究结果表明,松嫩平原盐碱地中耐盐菌与嗜盐菌种群丰富,主要以葡萄球菌和盐单胞菌为主,菌株不仅耐盐能力高而且耐碱能力也高,并且该地区可能含有丰富的耐盐菌和嗜盐菌的新物种。

[Objective] To analyze the biodiversity of halotolerant and halophilic bacteria the bacteria in saline-alkaline soils in Songnen Plain,we isolated and purified bacteria samples in the area.,[Methods] Halotolerant and halophilic bacteria were isolated from the enriched cultures of the saline-alkline soil samples through the traditional culture method,and 16S rRNA sequences were amplified and analyzed for the determination of phylogenetic relationships.[Results] Forty strains were obtained and classified into 34 species,16 genera,8 families,3 phylum（Firmicutes,γ-Proteobacteria and Actinobacteria） in the Domain Bacteria.The genus Staphylococcus is the predominant group,followed by Halomonas,Oceanbacillus,Bacillus,Kocuria and Pseudomonas.The 16S rRNA sequences of 9 strains showed 97.2 to 99.0% similarities with their closest type strains,suggesting that they may be the potential novel species.The salt tolerance of the strains is mainly concentrated on the 5%-10% NaCl while alkaline pH resistance of the strains is between pH 9 and 12.Based on the NaCl dependence,62.5% of the strains were grouped into the halotolerant bacteria,and the rest into the moderate halophiles.[Conclusion] The halotolerant and halophilic bacteria are very rich in the saline-alkaline soils in Songnen Plain,and the genera Staphylococcus and Halomonas are the predominant groups.Almost all the bacteria from this area could tolerate not only at the high concentration of NaCl,but also at high alkaline pH.More importantly,a number of novel species may be included in this area.