Growth, activity and temperature responses of ammonia-oxidizing archaea and bacteria in soil microcosms
Growth, activity and temperature responses of ammonia-oxidizing archaea and bacteria in soil microcosms
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DOI：
10.1111/j.1462-2920.2007.01563.x
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发表时间：
2008-05-01
影响因子：
5.1
通讯作者：
Prosser, James I.
中科院分区：
文献类型：
--
作者：
Tourna, Maria;Freitag, Thomas E.;Prosser, James I.
氨氧化作为硝化过程的第一步，在氮的全球循环中起着核心作用。虽然传统上认为细菌是氨氧化的原因，但宏基因组研究的数据和分离出的一种自养、氨氧化、非嗜热的海洋古细菌表明了古细菌的作用。海洋和陆地环境中非嗜热古细菌氨氧化的证据主要基于细菌和古细菌氨单加氧酶（amo）基因的丰度，而不是活性。本研究通过分析16S rRNA基因和编码氨单加氧酶a亚基的关键功能基因amoA的转录活性，确定了温度对硝化土壤微生物中氨氧化细菌和古细菌反应的影响。在硝化过程中，氨氧化细菌的相对丰度和转录活性几乎没有变化。相比之下，对古细菌16S rRNA和amoA基因的变性梯度凝胶电泳分析为活性古细菌氨氧化剂群落结构的变化提供了强有力的证据。在不同温度的孵育期间，群落结构的变化是相似的，大部分活动是由于与地下和海洋环境有关的一组非嗜热crenarchaea，而不是土壤。研究结果表明，crenarchaea在土壤硝化作用中的作用，需要进一步了解其生物地理学。
Ammonia oxidation, as the first step in the nitrification process, plays a central role in the global cycling of nitrogen. Although bacteria are traditionally considered to be responsible for ammonia oxidation, a role for archaea has been suggested by data from metagenomic studies and by the isolation of a marine, autotrophic, ammonia-oxidizing, non-thermophilic crenarchaeon. Evidence for ammonia oxidation by non-thermophilic crenarchaea in marine and terrestrial environments is largely based on abundance of bacterial and archaeal ammonia monooxygenase (amo) genes, rather than activity. In this study, we have determined the influence of temperature on the response of ammonia-oxidizing bacteria and archaea in nitrifying soil microcosms using two approaches, involving analysis of transcriptional activity of 16S rRNA genes and of a key functional gene, amoA, which encodes ammonia monooxygenase subunit A. There was little evidence of changes in relative abundance or transcriptional activity of ammonia-oxidizing bacteria during nitrification. In contrast, denaturing gradient gel electrophoresis analysis of crenarchaeal 16S rRNA and crenarchaeal amoA genes provided strong evidence of changes in community structure of active archaeal ammonia oxidizers. Community structure changes were similar during incubation at different temperatures and much of the activity was due to a group of non-thermophilic crenarchaea associated with subsurface and marine environments, rather than soil. The findings suggest a role for crenarchaea in soil nitrification and that further information is required on their biogeography.