比什凯克盐碱土壤可培养细菌的多样性

Diversity of bacteria isolated from saline alkali soil of Bishkek region in Kyrgyzstan

摘要:

【目的】通过对吉尔吉斯共和国比什凯克地区一处盐碱土壤样品可培养细菌的分离筛选，初步了解该地区土壤微生物生理多样性和系统发育多样性。【方法】利用加盐(NaCl 5%)的R2A、TSB、1/4×NA和Gause No.1培养基筛选耐盐碱菌株。对部分分离菌株的革兰氏染色、耐盐性、生长温度范围、pH耐受、产酶性能进行了比较，进而采用核糖体DNA扩增片段限制性酶切分析(ARDRA)研究了比什凯克地区耐盐碱细菌的群落结构和多样性。【结果】从比什凯克地区盐碱土样中分离得到120株耐盐碱细菌，通过限制性内切酶Hae III对纯化菌株的16S rRNA基因进行酶切分型，根据ARDRA的酶切图谱，将其划分为19个操作分类单元。16S rRNA基因序列测定和系统发育分析结果显示，分离菌株分布于厚壁菌门、放线菌门、变形菌门下的17个种属，且部分菌株的16S rRNA基因序列同源性低于97%，可能是潜在的新种。【结论】比什凯克地区盐碱土样中的耐盐碱细菌不仅具有丰富的多样性，还蕴藏着具有地域特点的新菌种资源。

Abstract:

[Objective] The diversity of culturable bacteria in saline alkali soil of Bishkek region in Kyrgyzstan was detected by Physiological test and phylogenetic analysis. [Methods] Using the screening media (R2A, TSB, 1/4 x NA and Gause No. 1 medium) containing 5% NaCl, salt resistant strains were screened. Based on morphological characteristics involving gram staining, salt resistance, growth temperature, pH tolerance and enzyme production performance, we researched the taxonomic identity and genetic variability of strains isolated by ARDRA classification map. [Results] One hundred and twenty salt-tolerant strains were isolated from Bishkek saline soil samples. Restriction enzyme Hae III was applied in ARDRA and 19 operational taxonomic units (OTUs) were assigned on the basis of the ARDRA patterns. Each OTU was randomly chosen for 16S rRNA gene sequencing. The phylogenetic analysis on the basis of 16S rRNA gene homology showed that all isolates affiliated to 17 genera, belonged to Firmicutes, Proteobacteria and Actinobacteria. Two of the isolates showed less affilation with known taxon (<97% sequence similarity) and may represent novel taxa. [Conclusion] The results suggest that the salt-tolerant bacteria are abundant, and some unknown taxa maybe exist in Bishkek region.