Shifts between Nitrospira- and Nitrobacter-like nitrite oxidizers underlie the response of soil potential nitrite oxidation to changes in tillage practices
Shifts between Nitrospira- and Nitrobacter-like nitrite oxidizers underlie the response of soil potential nitrite oxidation to changes in tillage practices
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DOI：
10.1111/j.1462-2920.2009.02070.x
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发表时间：
2010-02-01
影响因子：
5.1
通讯作者：
Le Roux, X.
中科院分区：
文献类型：
--
作者：
Attard, E.;Poly, F.;Le Roux, X.
尽管亚硝酸盐氧化细菌（NOB）在土壤功能中发挥着重要作用，但它们的生态学及其对农业实践产生的干扰的反应却鲜为人知。在 17 个月的时间里，我们调查了四种处理土壤中潜在的亚硝酸盐氧化、PNO、硝化细菌和类硝化螺旋 NOB 的丰度（通过定量 PCR）以及类硝化细菌 NOB 的群落结构（通过 PCR-DGGE 和针对 nxrA 基因的克隆测序）：在先前免耕系统上建立耕作后、在先前耕作系统上停止耕作后以及控制耕作和免耕系统。还调查了关键土壤变量（水分、有机碳含量和总矿化度 - 即氨化作用 - 通过 15N 稀释技术测量）。免耕处理的 PNO 始终高于耕作处理。耕作的开始导致 PNO 急剧而强烈地下降，而停止耕作即使在 17 个月后也没有改变 PNO。 PNO 与类硝化细菌 NOB 的丰度呈强正相关，并且与总矿化度（氮有效性的代表）也呈强相关；相反，PNO 与 Nitrospira 样 NOB 的丰度呈弱负相关。在免耕条件下观察到优势种群的选择，PNO 与类硝化细菌 NOB 的群落结构松散相关。我们的结果表明，在氮利用率高、活性水平高的土壤中，类硝化细菌 NOB 是 NOB 群落中的关键功能参与者，PNO 的变化是由于硝化螺旋菌类 NOB 和类硝化细菌 NOB 之间的变化造成的，并且在较弱的程度上是由类硝化细菌 NOB 内种群的变化引起的。
P>Despite their role in soil functioning, the ecology of nitrite-oxidizing bacteria, NOB, and their response to disturbances such as those generated by agricultural practices are scarcely known. Over the course of 17 months, we surveyed the potential nitrite oxidation, PNO, the abundance of the Nitrobacter- and Nitrospira-like NOB (by quantitative PCR) and the community structure of the Nitrobacter-like NOB (by PCR-DGGE and cloning-sequencing targeting the nxrA gene) in soils for four treatments: after establishment of tillage on a previously no-tillage system, after cessation of tillage on a previously tillage system, and on control tillage and no-tillage systems. Key soil variables (moisture, organic carbon content and gross mineralization - i.e. ammonification - measured by the 15N dilution technique) were also surveyed. PNO was always higher for the no-tillage than tillage treatments. Establishment of tillage led to a strong and rapid decrease in PNO whereas cessation of tillage did not change PNO even after 17 months. PNO was strongly and positively correlated to the abundance of Nitrobacter-like NOB and was also strongly related to gross mineralization, a proxy of N-availability; in contrast, PNO was weakly and negatively correlated to the abundance of Nitrospira-like NOB. Selection of a dominant population was observed under no-tillage, and PNO was loosely correlated to the community structure of Nitrobacter-like NOB. Our results demonstrate that Nitrobacter-like NOB are the key functional players within the NOB community in soils with high N availability and high activity level, and that changes in PNO are due to shifts between Nitrospira-like and Nitrobacter-like NOB and to a weaker extent by shifts of populations within Nitrobacter-like NOB.