Abundance and diversity of ammonia-oxidizing bacteria in rhizosphere and bulk paddy soil under different duration of organic management
Abundance and diversity of ammonia-oxidizing bacteria in rhizosphere and bulk paddy soil under different duration of organic management
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DOI：
10.5897/ajmr10.749
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发表时间：
2011-12
影响因子：
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通讯作者：
Shu Wang;Jun Ye;P. Pérez;Danfeng Huang
中科院分区：
文献类型：
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作者：
Shu Wang;Jun Ye;P. Pérez;Danfeng Huang
采用变性梯度凝胶电泳（DGGE）和定量实时PCR（qPCR）方法分别评估常规管理和不同有机管理年限（2、3、5、9年）根际和大块水稻土中nifH基因序列的分子多样性和数量。基于nifH基因序列的克隆的系统发育分布表明，分类群由Alphaproteobacteria（27.6%）、Betaproteobacteria（24.1%）和Gammaproteobacteria（48.3%）组成。根瘤菌目和假单胞菌目成员在主要的固氮生物中普遍存在。当通过qPCR测定nifH基因序列的数量时，检测到2.27×105至1.14×106拷贝/g土壤。除2年有机管理土壤外，有机土壤（根际和土壤）中的nifH基因拷贝数均显着高于CM土壤。此外，有机根际土壤（3、5、9年）中的nifH基因拷贝数显着高于块状土壤。固氮细菌的丰度和多样性随着有机管理的持续时间而增加，但在5年有机管理的根际和土壤中观察到nifH基因拷贝数最高。此外，方差分析和典型对应分析（CCA）表明，C/N、C和N是影响固氮细菌丰度和群落结构的重要因素。
Denaturing gradient gel electrophoresis (DGGE) and quantitative real-time PCR (qPCR) approaches were used to assess respectively the molecular diversity and quantity of the nifH gene sequences in rhizosphere and bulk paddy soil under conventional management and different duration of organic management (2, 3, 5, 9 years). The phylogenetic distribution of clones based on nifH gene sequence showed that taxonomic groups were consisted of Alphaproteobacteria (27.6%), Betaproteobacteria (24.1%) and Gammaproteobacteria (48.3%). Members of the order Rhizobiales and Pseudomonadales were prevalent among the dominant diazotrophs. When the quantity of the nifH gene sequences was determined by qPCR, 2.27 × 105 to 1.14 × 106 copies/g of soil were detected. Except for 2 years organically managed soil, nifH gene copy numbers in organic soil, both rhizosphere and bulk, were significantly higher than in CM soil. Moreover, nifH gene copy numbers in the organic rhizosphere soil (3, 5, 9 years) were significantly higher than in bulk soil. The abundance and diversity of nitrogen-fixing bacteria tended to increase with duration of organic management but the highest number of nifH gene copies was observed in the rhizosphere and bulk soil of 5 years organic management. In addition, analysis of variance and canonical correspondence analysis (CCA) showed that C/N, C and N were important factors influencing the abundance and community structure of nitrogen-fixing bacterial.