东北旱田土壤中Anabaena伴生细菌的分离与鉴定

Isolation and identification of bacteria associated with Anabaena from upland soils in northeast China

[背景]鱼腥藻(Anabaena)在农田土壤中广泛分布,具有固碳和固氮功能。明确伴生细菌与蓝细菌的关系,对提高农田土壤中Anabaena的功能具有重要意义。[目的]从东北不同旱田土壤中分离Anabaena sp.PCC7120的伴生细菌,初步鉴定伴生细菌的分类归属,推测伴生细菌的功能,为明确旱田土壤蓝细菌与伴生细菌的关系提供数据支撑。[方法]采用平板分离、PCR-DGGE、克隆测序技术测定并分析不同旱田土壤中伴生细菌的16S rRNA基因序列,确定伴生细菌的分类地位。[结果]PCR-DGGE图谱显示东北旱田14个土样中分离获得Anabaena sp.PCC7120伴生细菌数量和种类不同;PCR-克隆测序获得伴生细菌的16S rRNA基因序列37条,可鉴定到种水平的菌株36条,主要归为鞘氨醇盒菌属(Sphingopyxis)、贪噬菌属(Variovorax)、黄杆菌属(Flavobacterium)和红球菌属(Rhodococcus)等,推测这些伴生细菌具有适应寡营养、富集微量元素、清除毒素等功效。[结论]东北旱田不同土壤中Anabaena sp.PCC7120伴生细菌种类和数量各异,这些伴生细菌主要隶属于Sphingopyxis、Variovorax、Flavobacterium和Rhodococcus等属。

[Background] Anabaena distribute widely in agricultural soils and have the ability of fixing-carbon and fixing-nitrogen. Clarifying the relationship between cyanobacteria and their associated bacteria is beneficial to improve the function of Anabaena in agricultural soils. [Objective] To isolate associated bacteria with Anabaena sp. PCC7120 from different upland soils in northeast China, to taxonomically identify the associated bacteria, to speculate the function of associated bacteria, and to provide data support for clarifying the relationship between soil cyanobacteria and their associated bacteria. [Methods] Isolation from cultured plate, PCR-DGGE and cloning-sequencing were used to obtain and analyze 16 S rRNA gene sequences of associated bacteria with Anabaena sp. PCC7120 from different upland soils and to determine their taxonomic position. [Results] PCR-DGGE profiles showed there are different quantity and type of associated bacteria with Anabaena sp. PCC7120 from 14 upland soils in northeast China. PCR cloning-sequencing result showed that 37 sequences of associated bacteria were obtained, and 36 sequences were identified at species level. The associated bacteria mainly belong to Sphingopyxis, Variovorax, Flavobacterium, Rhodococcus, and these bacteria were suspected with the functions of adapting oligotrophic condition, enriching trace elements, removing toxins. [Conclusion] There are different quantity and type of associated bacteria with Anabaena sp. PCC7120 from upland soils in northeast China. These associated bacteria were mainly members of Sphingopyxis, Variovorax, Flavobacterium and Rhodococcus.