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

我们建议研究的影响，环境触发器的时间生产的N2 O，数量和表达的反硝化基因和它们的作用，调节反硝化和N2 O排放。主要感兴趣的土壤环境条件或触发因素是电子供体（碳）的添加、电子受体（N氧化物）的添加、水分和温度波动。已经确定了这项赠款申请的几个短期目标：1）利用可调谐半导体激光-微量气体分析仪（TDL-TGA），研究碳、氮、热和水文事件对反硝化和N2 O排放的触发作用。2）利用最新的分子生物学技术，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时间响应，以及它们在反硝化和N2 O排放中的调控作用。评估目前用于检查快速和长期时间响应的引物的代表性。4）检查长期（十年）土壤过程对土壤特性的影响（有机质含量，土壤结构/建筑），表现在土壤景观与短期影响（每日/季节）进程（碳，氮，温度和水分添加）对马铃薯种植系统完整土样中关键基因的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.