高通量技术解析锡林河底泥反硝化菌群组成及丰度

Pyrosequencing Analysis Reveals Abundance and Community Composition of Denitrifying Bacteria in Xilin River Sludge

反硝化菌驱动的脱氮作用是全球氮循环的重要环节,其群落组成及丰度对气态氮产生的类型和排放量有调控作用。本文结合文献报道的反硝化细菌属,基于16S rRNA基因454焦磷酸测序检测了锡林河底泥中反硝化细菌群落结构组成和丰度。结果发现:5744条优化序列在“属”水平上聚类成2263个OTUs,与GenBank中已知序列比对后获得未分类的细菌属占57.49%。已分类的204个细菌属中20个为反硝化细菌属,包括Flavobacterium 1.40%,Hydrogenophaga 1.23%,Bacillus和Thauera 0.19%,Thiobacillus 0.17%,Hyphomicrobium 0.15%等。其中,黄杆菌属Flavobacterium和噬氢菌属Hydrogenophaga是锡林河底泥中最丰富的反硝化细菌,共占反硝化菌群总组成的69.03%。相关性分析表明:Flavobacterium更喜欢pH相对高的沙粒,促进CH4排放并抑制N2O和CO2产生;而Hydrogenophaga更喜欢营养丰富的细粒,促进N2O和CO2排放并抑制CH4产生。

Nitrogen loss caused by denitrifying bacteria is an important link in the global carbon-nitrogen cycles, whose community compositions and abundance may have a role in regulating emissions and forms of gaseous nitrogen. Based on 454 pyrosequencing of the 16S rRNA gene, as well as the reported denitrifying bacterial genera mentioned in many literatures, we detected community compositions and abundance of denitrifying bacterial communities in Xilin River sludge. The results showed that 5744 quality reads were grouped into 2263 OTUs at genus level (0.05 distance). After alignment with known sequences deposited in GenBank, the unclassified bacteria genera accounted for 57.49%. 204 classified bacterial genera covered 20 denitrifying bacteria genera, including 1.40% of Flavobacterium, 1.23% of Hydrogenophaga, 0.19% of Bacillus and Thauera, 0.17% of Thiobacillus, 0.15% of Hyphomicrobium, etc. Among them, Flavobacterium and Hydrogenophaga were the most dominant denitrifying bacterial genera in Xilin River bottom sludge, accounting for 69.03% of the total denitrifying bacterial genera. Correlation analysis showed that Flavobacterium preferred to attach to coarse sand grains in relatively high pH conditions, promoting the emission of CH4 and inhibiting the production of N2O and CO2. In opposition, Hydrogenophaga showed special preference to fine silt grains in rich nutrition conditions, promoting the emission of N2O and CO2 and inhibiting the production of CH4.