Genetic characterization of denitrifier communities with contrasting intrinsic functional traits
Genetic characterization of denitrifier communities with contrasting intrinsic functional traits
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DOI：
10.1111/j.1574-6941.2011.01237.x
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发表时间：
2012-02-01
影响因子：
4.2
通讯作者：
Bakken, Lars R.
中科院分区：
文献类型：
--
作者：
Braker, Gesche;Dorsch, Peter;Bakken, Lars R.
具有反硝化能力的微生物是多源的，并表现出不同的反硝化调节表型（DRP），因此，土壤中的反硝化作用可以通过群落组成来控制。在一项伴随研究（Dorsch等人，2012）和之前的工作，三种有机土壤的异位反硝化测定显示出深刻不同的功能性状，包括N2 O/N2比。在这里，我们探讨了组成的底层反硝化细菌群落通过分析反硝化基因（nirK，nirS和nosZ）的丰度和结构。nosZ（相对于nirK + nirS）的相对丰度是相似的所有社区，因此，在一个土壤中的N2 O还原酶活性低，是不是因为缺乏这种基因的生物。群落组成的土壤之间的相似性普遍较低的nirK和nirS，但不是nosZ。最强大的反硝化（始终低N2 O/N2）的社区有最高的多样性/丰富度的nosZ和nirK，但不是nirS。相反的结果发现，第二土壤同意受损的反硝化作用（整体反硝化活性低，高N2 O/N2）。总之，群落组成和反硝化基因的绝对丰度的差异清楚地反映了在实验室研究中观察到的功能差异，并可能揭示在原位N2 O排放的土壤差异。
Microorganisms capable of denitrification are polyphyletic and exhibit distinct denitrification regulatory phenotypes (DRP), and thus, denitrification in soils could be controlled by community composition. In a companion study (Dorsch et al., 2012) and preceding work, ex situ denitrification assays of three organic soils demonstrated profoundly different functional traits including N2O/N2 ratios. Here, we explored the composition of the underlying denitrifier communities by analyzing the abundance and structure of denitrification genes (nirK, nirS, and nosZ). The relative abundance of nosZ (vs. nirK + nirS) was similar for all communities, and hence, the low N2O reductase activity in one of the soils was not because of the lack of organisms with this gene. Similarity in community composition between the soils was generally low for nirK and nirS, but not for nosZ. The community with the most robust denitrification (consistently low N2O/N2) had the highest diversity/richness of nosZ and nirK, but not of nirS. Contrary results found for a second soil agreed with impaired denitrification (low overall denitrification activity, high N2O/N2). In conclusion, differences in community composition and in the absolute abundance of denitrification genes clearly reflected the functional differences observed in laboratory studies and may shed light on differences in in situ N2O emission of the soils.