Community Structure Analysis Of Bacteria And Ammonia-Oxidizing Bacteria In Steppe And Wetland Soil

Wetlands are important natural environment of human resources, it has great environmental regulation features and ecological benefits. Though there are rich resources in Inner Mongolia Plateau wetland soil, it is also the most threatened ecosystems which is rarely studied and reported. The function of Wetlands as a nitrogen source, sink or converter in the global biogeochemical cycles has increasingly attracted people's attention. Though there are rich wetland resources in Mongolian Plateau, it is also the most threatened ecosystems which is rarely studied and reported. The study about the community structure changes of N-cycle bacteria in the area is almost blank.In this paper, we studied the community structure and Genetic diversity of wetland soil bacteria and ammonia oxidizing bacteria (AOB) in Xilin River of Inner Mongolia Plateau by 16S rDNA-PCR-DGGE, and sequenced certain typical dominant AOB groups, constructed the phylogenetic tree. The main results are as follows:Shannon-wiener Index (H),Richness (S) and Evenness (E) both in bacteria and AOB increased and then decreased from the 5 terrestrial distribution samples:samples of sediment collected in the bottom at the centre river (HX)→samples of sediment collected in the riverside (HB)→samples collected in the low floodplain (DQ)→samples collected in the high floodplain (EQ)→samples collected in the typical steppe (TN), showed that the community structure and diversity of bacteria and AOB had obviously land distribution features. Wetland transition areas of high soil microorganisms diversity, can provide a microbial ecology basis for the high biological productivity in this area.Shannon-wiener Index (H),Richness (S) in the towertip was higher than the indexes in the sample among towers whether in enclosed or garzing plots. Indicating that the towertip was more sutiable for the aerobic bateria to survive.Cluster analysis of the DGGE patterns demonstrated that the diversity of bacterial in 3 river samples HX, HB, DQ was simple with each other; the AOB in 2 river samples HX, HB and WJ, FJ samples between towers that Perennial flooded can be clustered together, concluded that water environment is a very important factor infect the bacteria's community structures.From the sequencing of the AOB partial 16srRNA genes fragments and study of phylogenetic tree, we find that the community was dominanted by beta Proteobacteria, most of them were Nitrosospira-related and Nitrosomonas-related sequences, we infered that in the river environment, Nitrosomonas sp. may be the dominant species. Our research can provide basic data for the Inner Mongolia Plateau wetlands nitrogen cycle, contribute to global climate change and provide a theoretical basis for ecological and environmental protection.