Molecular Ecological Characterization Of Different Treatments On Microbial Community Structure In Acid Sulfate Soil

Sulfur is one of the most necessary nutrients for rice growth. Sulfate-reducing bacteria(SRB) are the main functional microbial group and play important roles in sulfate reduction in the rice paddy soils. Acid sulfate soils contain iron sulfide.When the soils are drained, exposed to air by a lowering of the water falde, the sulfides react with oxygen to form sulfuric acid. In this study, a series of uncultivated and cultivated (paddy field) acid sulfate soils were used to test.The potential responses of bacteria、archaea and SRB community structure soil amendments, using culture-independent molecular techniques such as soil DNA extraction, polymerase chain reaction (PCR), real-time PCR, denaturing gradient gel electrophoresis (DGGE) and sequencing. The major contents and findings of the main results are as follows:1. The basic chemical properties in the paddy soil, i.e., soil pH, organic C, available P and sulfate concentrations increased significantly with soil modification.Soil microbial biomass C showed a significantly increase compared with the control. Biochar (5%) had higher effect on microbial biomass C than manure (5%) or lime (1%)2. The lateral community structure was investigated in order to understand the response to different amendments in rice paddy, including lime (1%), Biochar (5%), manure (5%). Significant differences in the bacterial were observed among different treatments, but the dominant taxa had no Significant differences.Sequence-based analysis of16S rDNA indicated that the dominant taxa were Actinomyces, Uncultured bacterium, Thiomonas and Deltaproteobacteria.3. The SRB community structure and sulfate reduction process in paddy soils amending with biochar manure and lime were examined in the culture experiment. No significant differences of SRB community structure were observed among different paddy soils amending with biochar manure and lime treatments, however significantly increased in the natural amended paddy soil. Phylogenetic analysis indicated that Desulfonema, Desulfomicrobium, Desulfovibrio, Thiococcus, Thiobacillus and Uncultured SRB were found, uncultured SRB were also found with a high proportion in the paddy soils.4. The archaea types were very abundance in different amended paddy soil. There were significant discrepancy in archaea diversity among different soil, due to the influence of pH, soil moisture, the content of carbon and other factors. High archaea biological diversity was found in the acidic soil. The results showed that there were some degree of decline in archaea community structure under the different amendments. The phylogenetic analysis based on the DGGE profiles showed that the archaea dominant taxa was Thermoprotei、Methanobacteria and Uncultured bacterium.