Terminal Restriction Fragment Length Polymorphism Analysis Of Methanotrophs In Wetland Soils Of Dry-Uplake In The Inner Mongolia Plateau

Methane is not only important source of energy and chemical raw material, but also one of the most important greenhouse gases, which is only second to carbon dioxide in the atmosphere. Aerobic methanotrophs are the sole biological sink for methane in aerobic soils, which is significant to reduce the greenhouse gas emission and manage the carbon cycling. Wetlands represent a major global source of methane, and they are being disrupted by human activity. So it is significant to biologically control the greenhouse effect and atmospheric environment by studying ecological distribution of methanotrophs in soils, exploring the effects of ecological environment on community structure and diversity in drying-up wetland. By using modern molecular ecology techniques, there are many studies of methanotrophs in farmlands, forests, grasslands, wetlands and sea, but less in wetland of dry-up lake.The method of terminal restriction fragment length polymorphism (T-RFLP) was used to study the key functional gene pmoA of the aerobic methanotrophs by capillary electrophoresis in the wetland soils of dry-up lake in the Inner Mongolia Plateau. Basing on the biodiversity analysis, hierarchical cluster analysis and principal component analysis (PCA), the results as follows:The diversity and evenness indexes of methanotrophs were higher at the later dry-up plots (S1and S2), and the opposite results were shown at the earlier dry-up plot (S3) and the adjacent steppe (S4).The methanotrophs’ similarity coefficients gradually declined from the centre of the lake to the adjacent steppe, indicating community’s dynamic succession. The terminal restriction fragment of95bp represented the dominant species owned by S1, S2and S3.457bp represented another dominant species of S2, and131bp represented another dominant species of S3.82bp and89bp represented the dominant species of S4.Basing on the multivariate analysis of T-RFLP, the principal component analysis biplot showed that the soil ammonium nitrogen was the main factor which effected methanotrophs community. The soil water content, C/N and soil organic matter had significant influence on the methanotrophs of S1, S2and S3, respectively. In addition, high pH value (8.5～9.7) had inhibitory effects on the whole soil microbial community, but it did not have influence on methanotrophs.The analysis of T-RFLP was affected by some important factors, including the specificity of PCR primer, the selection of restriction enzyme, the concentration of DNA samples and the screening of the T-RFLP peak profiles, and so on.