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Unraveling community structure, ecophysiology, and regulation of new acid-tolerant denitrifiers driving high N2O emissions from cryoturbated peat soil in acidic tundra

揭示酸性苔原低温扰动泥炭土中新型耐酸反硝化菌的群落结构、生态生理学和调控，导致高氧化亚氮排放

基本信息

批准号：
220549886
负责人：
Professor Dr. Marcus A. Horn
金额：
--
依托单位：
Institut für Mikrobiologie (ifmb)
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2012
资助国家：
德国
起止时间：
2011-12-31 至 2017-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/220549886?language=en
关键词：
Unraveling community structure ecophysiology regulation

项目摘要

Cryoturbated peat circles in arctic tundra are ‘hot spots’ of N2O emission, while adjacent unturbated peat sites are not. Such permafrost-affected systems are projected to react to global warming and harbor new acid-tolerant denitrifiers. Although denitrification is a major source of N2O in peatlands, and denitrifiers contribute to the control of N2O emissions, the ecophysiology and spatial distribution of active denitrifiers in cryoturbated and unturbated peat is essentially unknown. Thus, the vertical and horizontal distribution of active denitrifiers associated with N2O emissions, and the effect of experimental warming on such organisms will be addressed by structural gene and transcript directed barcoded amplicon pyrosequencing and qPCR, most probable numbers, total cell counts, microcosms, and N2O-flux measurements in the field. Dissimilatory nitrate reducers (DNRA) might release N2O and will likewise be assessed. New active key structural genes of denitrifiers and the relative importance of Bacteria, Archaea, and Fungi will be determined by the ‘double RNA approach’ and ‘subtractive transcriptomics’. ‘Differentiating pyrosequencing based RNA and DNA stable isotope probing’ will be applied to elucidate 16S rRNA genes concomitant to structural genes of active organic acid assimilating denitrifiers and DNRA. The regulation of new denitrifiers by temperature, O2, and pH will be evaluated in microcosms by structural gene and transcript directed qPCR together with process analyses. New denitrifiers will be isolated and characterized by a directed cultivation strategy.

北极冻土带的低温扰动泥炭圈是N2O排放的“热点”，而邻近的未扰动泥炭地则不是。这种受永久冻土影响的系统预计会对全球变暖做出反应，并孕育新的耐酸反硝化菌。尽管反硝化作用是泥炭地N2O的主要来源，而反硝化剂有助于控制N2O的排放，但活性反硝化剂在低温扰动和非扰动泥炭中的生态生理和空间分布基本上是未知的。因此，与N2O排放相关的活性反硝化菌的垂直和水平分布，以及实验变暖对这些生物的影响，将通过结构基因和转录本定向条形码扩增子焦磷酸测序和qPCR、最可能数量、总细胞计数、微生物和野外N2O通量测量来解决。异化硝酸盐还原剂（DNRA）可能释放N2O，并将同样进行评估。反硝化菌的新活性关键结构基因以及细菌、古细菌和真菌的相对重要性将通过“双RNA方法”和“减法转录组学”来确定。“区分焦磷酸测序的RNA和DNA稳定同位素探测”将用于阐明与活性有机酸同化反硝化菌和DNRA结构基因伴随的16S rRNA基因。通过结构基因和转录本定向qPCR以及工艺分析，将在微观环境中评估温度、O2和pH对新型反硝化菌的调节作用。新的反硝化菌将通过定向培养策略进行分离和鉴定。