中国典型冻土区土壤可培养细菌多样性

Diversity of culturable bacteria in the typical frozen soil areas in China

摘要:

摘要:【目的】对比分析中国典型高纬度冻土区和高海拔冻土区土壤可培养细菌的多样性。【方法】采用NM、TSA、R2A 3 种培养基分离培养不同冻土区土壤可培养细菌，用通用引物扩增分离的细菌16S rRNA 基因，根据系统发育分析进行鉴定。【结果】从6 个样品中得到冻土土壤可培养细菌的菌落数量为4．70×103－2.57×105 cfu/g(土壤干重) ，根据不同的菌落形态分离出144 株可培养细菌。纯培养物的16S rRNA 基因部分序列分析表明:我国高纬度冻土区土壤样品中的细菌分别属于Firmicutes 分支(59. 52%)、Gammaproteobacteria分支(38.10%)、Betaproteobacteria 分支(2.38%)，其中假单胞菌属(Pseudomonas)、芽胞杆菌属(Bacillus)、类芽胞杆菌属(Paenibacillus) 的菌株为该区域的三大优势菌群。我国高海拔冻土区土壤样品中分离细菌属于Gammaproteobacteria 分支(89.22%)、Firmicutes 分支(8.82%)和Bacteroidetes 分支(1.96%)。优势菌群为假单胞菌属(Pseudomonas)。【结论】我国高纬度冻土区和高海拔冻土区土壤具有较高的可培养细菌多样性;不同类型冻土区土壤可培养细菌群落组成不同。本文研究结果将为我国冻土区土壤细菌资源研究与利用提供理论依据。

Abstract:

Abstract:［Objective］The diversity of culturable bacteria in the six frozen soils from High-latitude area and High-altitude area were analyzed by using culture-dependent approaches．［Methods］Three solidified media were used to isolate culturable bacteria． Bacterial 16S rRNA genes of the isolates were PCR amplified using bacteria-universal primers，and then were sequenced． The resulting bacterial 16S rRNA gene sequences were subjected to phylogenetic analysis．［Results］The abundance of culturable bacteria ranged from 4.70×103 to 2.57×105 colony forming units (CFU) per gram of soils (dry weight)． A total of 144 bacterial strains were obtained． The bacterial isolates from the High-latitude area were affiliated with three phyla (Firmicutes，Gammaproteobacteria，and Betaproteobacteria) with Pseudomonas，Bacillus，and Paenibacillus strains being dominant． The bacterial isolates from High-altitude area could be grouped into three different phyla (Gammaproteobacteria，Firmicutes，and Bacteroidetes) with Pseudomonas strains be dominant． ［Conclusion］The culturable bacteria are abundant and diverse in the frozen soils of High-latitude and High-altitude areas． The results also showed that the culturable bacterial community structure varied among different research areas．Our data have implications for a better understanding of culturable bacterial community in the frozen soils in China．