| Rhizosphere microbial communities of Soybean (Glycine max (L.) Merrill) are important for nutrient absorption and plant health. In order to manipulate microbial populations in rhizosphere benefit for plant growth, a better understanding of the relationship among soil, plant and microbial communities in rhizosphere is greatly needed. In the present study, using the plate culture and PCR-DGGE methods, which the DGGE banding patterns were evaluated by microbial species diversity index analysis, cluster analysis and principal component analysis (PCA). Three experiments were conducted to investigate the impact of soil type, genotype and development stage on the microbial community structures in rhizosphere of soybean.Three soybean genotypes (D2003-1, Hefeng25 and Suinong14) grown in two soil types (Mollisols and Alfisols), were involoved in a pot experiment and the results showed that the soil type was the major factor in shaping the microbial community structure in the rhizosphere, with stronger impact from Mollisls soil than Alfisols soil.Field experiment was only conducted in Alfisols soil with three soybean genotypes. The results from both field and pot experiments showed that microbial community in the rhizosphere succeeded with soybean development stage from the R1 stage to the R8 stage, which indicated the growth stage significantly influenced to the microbial diversity of soybean rhizoshere. Furthermore, this effect varied with the soil type with more stabilization in Mollisols than Alfisols on bacterial and not not detected in fungal community.However, in the plate culture experiment, the culturable bacterial community structures remarkably differed with genotypes, which suggested that genotype only affected a small portion of the total bacteria in rhizosphere, i.e., the fast-growing aerobic heterotrophic bacteria. But in the nature conditions, the difference between the two genotypes was not significant.Sequence analysis of the dominant bands suggested that Proteobacteria, Actinobacteria, Verrucomicrobia, Bacteriodetes, Firmicutes, Nitrospirae and Acidobacteria in bacteria; Ascomycota and Basidiomycota in fungi were commonly inhabited in the soybean rhizosphere. |
