黑龙江大豆轮作和连作土壤细菌群落多样性比较

Comparison of bacterial diversity in rotational and continuous soybean cropping soils in Heilongjiang

为研究大豆轮作和连作对土壤细菌群落多样性的影响,提取黑龙江大豆轮作和连作土壤微生物总DNA,采用细菌通用引物27F和1492R扩增了土壤细菌16S rDNA片段,构建了细菌16S rDNA克隆文库,并对文库中的细菌群落多样性进行了分析。通过16S rDNA序列同源性分析,发现76.5%克隆序列与环境中未培养细菌的16S rDNA序列有较高的相似性,仅有23.5%的克隆序列与GenBank数据库中可培养细菌有较高的相似性,表明黑龙江大豆田土壤中的多数细菌尚未培养。系统发育分析表明黑龙江土壤细菌分属于6大类群,其中变形菌Proteobacteria和酸杆菌Acidobacteria所占比例较大,另有少量厚壁菌Firmicutes、放线菌Actinobacteria、芽单胞菌Gemmatimonadetes和未分类的细菌。大豆轮作土壤细菌多样性更为丰富,并以变形菌为优势细菌类群;而大豆连作土壤细菌多样性有所减少,以酸杆菌为优势细菌类群。表明黑龙江大豆田土壤中细菌多样性十分丰富,其种植方式对土壤细菌群落结构影响较大。

Total DNA of the microbes in rotational and continuous soybean cropping soils in Heilongjiang were extracted and amplified using the bacterial general primers 27 F and 1492 R. The bacterial 16 S rDNA clone libraries were constructed and analyzed to study the effects of soybean rotational and continuous cropping on the soil bacterial diversity. The 16 S rDNA sequence homology analysis indicated that 76. 5%clone sequences were similar to those of uncultured bacteria in the environment,while only 23. 5% clone sequences were most closely related to those of cultured bacteria in GenBank,suggesting great potential for undeveloped bacterial resources available in soybean fields in Heilongjiang. Phylogenetic analysis also showed that the sequenced clones fell into 6 major lineages within the domain bacteria. Among them,members of the Proteobacteria and Acidobacteria were the dominant group. Firmicutes,Actinobacteria,Gemmatimonadetes and unclassified bacteria were less well represented. The bacterial diversity in rotational soils was rich,and the main bacterial group was Proteobacteria. But the bacterial diversity in soybean continuous cropping soils was somewhat decreased, and the main bacterial group was Acidobacteria. The results revealed high diversity of soil bacteria in soybean fields in Heilongjiang,and planting mode did have a significant impact on the soil bacterial community structure.