Environmental regulation of denitrifying activity in soil producing nitrous oxide and the expression of denitrifier genes in the soil bacteria

我们建议研究环境触发因素对N2O时间生成的影响、反硝化基因的数量和表达及其在调节反硝化和N2O排放中的作用。土壤环境条件或触发因素主要是电子供体（碳）的添加，电子受体（N氧化物）的添加，湿度和温度波动。该资助申请的几个短期目标已经确定：1)利用可调谐二极管激光痕量气体分析仪（TDL-TGA），研究碳、氮、热和水文事件作为反硝化和N2O排放触发因素的作用。2)利用最先进的分子工具，定量分析土壤中关键反硝化基因的数量和表达对环境条件的快速响应，以及它们在调节反硝化和N2O排放中的作用。3)建立马铃薯生产土壤中反硝化基因的反硝化菌和引物培养库，评估目前用于检测快速和长期响应的引物的代表性。4)研究受长期（年代际）土壤过程（有机质含量、土壤结构/结构）影响的土壤特征在土壤景观中与受短期（日/季节）过程（碳、氮、温度和水分添加）影响的土壤特征对马铃薯种植系统完整土芯中关键反硝化基因拷贝数和基因表达的影响

We propose to study the influence of environmental triggers on the temporal production of N2O, the number and expression of denitrifier genes and their role in regulating denitrification and N2O emissions. The soil environmental conditions or triggers that are of primary interest are the addition of electron donor (carbon), the addition of electron acceptor (N oxides), moisture and temperature fluctuation. Several short-term objectives for this grant application have been identified:1) Utilizing a tunable diode laser - trace gas analyzer (TDL-TGA), to study the role of carbon, nitrogen, thermal and hydrologic events as triggers of denitrification and N2O emissions.2) Utilizing state-of-the-art molecular tools, to quantity the rapid temporal response of the number and expression of key denitrification genes in soil to environmental conditions, and their role in regulating denitrification and N2O emissions.3) To build a culture library of denitrifiers and primers for the denitrification genes in soils under potato production, assessing the representativeness of primers currently being utilized to examine rapid and longer-term temporal responses.4) To examine the impact of soil characteristics influenced by long-term (decadal) soil processes (organic matter content, soil structure/architecture) as expressed in soil landscapes vs. those influenced by short-term (daily/seasonal) processes (carbon, nitrogen, temperature and moisture additions) on the number of gene copies and gene expression of key denitrifier genes in intact soil cores from a potato cropping system in N.B.