白洋淀冬季沉积物好氧反硝化菌垂向分布特征及群落构建

Vertical Distribution Characteristics and Community Construction of Aerobic Denitrification Bacteria from the Sediments of Baiyangdian Lake During the Winter Freezing Period

为了探究白洋淀冬季沉积物好氧反硝化菌群落垂向分布特征、关键物种和群落构建过程,结合好氧反硝化功能基因(napA)高通量测序技术,进行了微生物多样性分析、物种差异分析、关键物种识别和群落构建过程研究.结果表明,该时期白洋淀沉积物高通量测序得到13845个OTUs,共分为10个门类,其中第一大门类为变形菌门,达到29.03%~94.46%,从表层到底层呈下降趋势;占比前二的纲为β-Proteobacteria和γ-Proteobacteria;占比前三的属为Cupriavidus、Aeromonas和Thauera.微生物α多样性显示垂向分组间表层沉积物Chao1指数最大为3327.67±621.28,明显高于底层(2193.96±455.57);中层沉积物Simpson指数最大为0.97±0.013,明显高于表层(0.94±0.029).主成分分析和Venn图显示表层和底层间差异性最显著,Adonis分析表明垂向间存在极其显著差异(P<0.001);随机森林分析和网络分析的关键物种有交叉相同的物种(Bordetella),但差异贡献程度最高的物种不同,分别为Ferrimonas和unassigned;中性群落模型(NCM)结果显示从表层到底层解释率逐渐增大,整个淀区解释率最大(R^(2)=0.655),表、中和底层的标准化随机率(NST)分别为0.29±0.31、0.56±0.35和0.88±0.21,呈现极其显著差异(P<0.001);NCM和NST结果表明由表层到底层随机性选择过程主导程度呈现加强趋势.综上,通过对该时期沉积物好氧反硝化菌群垂向分布特征和群落构建过程进行研究,可为低温好氧反硝化菌的筛选提供技术支持.

To explore the vertical distribution characteristics,key species identification,and community construction of aerobic denitrification bacteria from the sediments of Baiyangdian Lake during the winter freezing period,a MiSeq high-throughput sequencing technique based on napA was used.Moreover,microbial diversity analysis,species difference analysis,key species identification,and community construction were carried out.The results showed that high-throughput sequencing obtained 13845 OTUs,which were divided into 10 phyla;Proteobacteria accounted for the largest proportion with 29.03%-94.46%and showed a decreasing trend from surface sediments to bottom sediments.The top two classes wereβ-Proteobacteria andγ-Proteobacteria,and the top three genera were Cupriavidus,Aeromonas,and Thauera.Theα-diversity showed that the maximum Chao1 index of surface sediments was 3327.67±621.28,which was significantly higher than that of bottom sediments(2193.96±455.57),and the maximum Simpson index of middle sediments was 0.97±0.013,which was significantly higher than that of surface sediments(0.94±0.029).The principal coordinates analysis and Venn diagrams revealed that there were significant differences between surface sediments and bottom sediments.Adonis analysis showed significant differences in vertical distribution(P<0.001).The random forest and network analyses had the same key species,such as Bordetella,but the species with the highest difference contribution degree differed(Ferrimonas and unassigned,respectively).The neutral community model(NCM)showed that the interpretation rate increased gradually from surface sediments to bottom sediments,and the whole area was the largest(R^(2)=0.655).The normalized stochasticity ratios(NST)were respectively 0.29±0.31,0.56±0.35,and 0.88±0.21 and showed significant differences(P<0.001).NCM and NST showed that the dominant degree of random selection process showed a strengthening trend from surface sediments to bottom sediments.Considering all results of this study,the vertical distribution characteristics of aerobic denitrification bacteria in sediments during this period can provide technical support for the screening of low-temperature aerobic denitrification bacteria.