PCR-DGGE技术解析东北稻田蓝藻群落结构

Cyanobacterial community structure in the paddy fields of northeast China estimated by PCR- DGGE method

[目的]明确东北稻田生态系统蓝藻群落结构组成变化及主要驱动因子。[方法]采用蓝藻特异性引物GC-Cya-b-F371和Cya-R783对采自东北不同土壤类型稻田土壤及田面水提取的DNA进行PCR扩增,采用DGGE电泳和条带测序技术解析稻田蓝藻群落结构。[结果]多样性指数表明,土壤中蓝藻群落结构比田面水体丰富。图谱冗余分析(RDA)显示,稻田土壤中蓝藻群落结构具有明显的地域差异,土壤碳氮比值是驱动土壤蓝藻分布的主要环境因素;而田面水体蓝藻群落结构地域差异不明显,p H值是驱动水体蓝藻分布的主要环境因素。DGGE条带测序发现,稻田蓝藻群落结构组成以丝状颤藻亚纲蓝藻(Oscillatoriophycideae)为主,一些条带基因序列与已知蓝藻相似度低于97%。[结论]东北稻田生态系统蓝藻群落结构复杂多样,生存着一些未知的蓝藻种群。

[ Objective] To explicit the cyanobacterial community structures in the paddy field ecosystems of Northeast China and its major driving environmental factors. [ Methods] The cyanobacterial specific primers GC - Cya - b - F371 and Cya - R783 were used for PCR amplification of extracted soil and floodwater DNAs obtained from different soil types of the paddy fields in Northeast China. The cyanobac- terial community structures were estimated by denaturing gradient gel electrophoresis （DGGE） banding patterns and sequencing methods. [ Results] Diversity indices showed that the cyanobacterial communities in the paddy soils are more abundant than those in the paddy floodwaters. The redundancy analysis （RDA） plots of DGGE banding patterns revealed that the cyanobacterial communities in different soil samples were distinctly different among sampling locations, and soil C/N ratio was ＂the major factor affecting the distribution of the cya- nobacterial composition; whereas, no distinctly difference of the cyanobacterial communities was observed in the paddy floodwaters,and the pH of floodwater was determined as the major factor affecting the distribution of the cyanobacterial communities. DGGE band sequencing showed that filamentous cyanobacterial members belong to Oscillatoriophycideae were dominated in the paddy fields, and several band se- quences had the highest similarity 〈 97% to the known cyanobacteria. [ Conclusion] Cyanobacterial coimnunities were very complexity and diversity, and several unknown cyanobacteria exist in the paddy fields of Northeast China.