Influence of different cultivars on populations of ammonia-oxidizing bacteria in the root environment of rice
Influence of different cultivars on populations of ammonia-oxidizing bacteria in the root environment of rice
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DOI：
10.1128/aem.68.6.3067-3075.2002
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发表时间：
2002-06-01
影响因子：
4.4
通讯作者：
Okuyama, H
中科院分区：
文献类型：
--
作者：
Briones, AM;Okabe, S;Okuyama, H
对不同水稻品种根环境中氨氧化细菌（AOB）的活性和分布进行了比较研究。尽管在生长过程中环境条件相同，但仍存在显著差异。通过N-15稀释技术获得的总硝化速率在现代品种IR 63087 -1-17中显著高于两个传统品种。系统发育分析的基础上铵单加氧酶基因（amoA）确定菌株相关的多形亚硝化螺菌和亚硝化单胞菌europaea为优势AOB在我们的实验水稻系统。建立了一种利用16 SrRNA荧光标记的寡核苷酸探针测定根生物膜样品上AOB丰度的方法。检测到的丰度水平表明水稻根部富集AOB。我们鉴定了IR 63087 -1-17根上40 - 69%的AOB为亚硝化单胞菌属，而其它品种根上的AOB中，该亚群占7 ~ 23%。amoA基因的变性梯度凝胶电泳和克隆的amoA文库的分析普遍支持这些结果。在水培条件下，不同水稻品种次生根周围的氧浓度分布存在显著差异，其中IR 63087 -1-17的氧泄漏量最大。结果表明，品种差异的组成和活性的根相关的AOB人口可能会导致微尺度差异O-2的可用性。
Comparisons of the activities and diversities of ammonia-oxidizing bacteria (AOB) in the root environment of different cultivars of rice (Oryza sativa L.) indicated marked differences despite identical environmental conditions during growth. Gross nitrification rates obtained by the N-15 dilution technique were significantly higher in a modern variety, IR63087-1-17, than in two traditional varieties. Phylogenetic analysis based on the ammonium monooxygenase gene (amoA) identified strains related to Nitrosospira multiformis and Nitrosomonas europaea as the predominant AOB in our experimental rice system. A method was developed to determine the abundance of AOB on root biofilm samples using fluorescently tagged oligonucleotide probes targeting 16S rRNA. The levels of abundance detected suggested an enrichment of AOB on rice roots. We identified 40 to 69% of AOB on roots of IR63087-1-17 as Nitrosomonas spp., while this subpopulation constituted 7 to 23% of AOB on roots of the other cultivars. These results were generally supported by denaturing gradient gel electrophoresis of the amoA gene and analysis of libraries of cloned amoA. In hydroponic culture, oxygen concentration profiles around secondary roots differed significantly among the tested rice varieties, of which IR63087-1-17 showed maximum leakage of oxygen. The results suggest that varietal differences in the composition and activity of root-associated AOB populations may result from microscale differences in O-2 availability.