Improving crop nitrogen use efficiency

在农业中使用氮肥对农民来说是一项很大的投入成本，对环境有深刻的负面影响。随着能源价格的上涨，氮肥的成本也将增加，因为其生产涉及到一个需要大量能源的过程。高投入作物依赖于氮肥的使用；然而，这些肥料中的大部分氮(约70%)作为径流流失到地表水和地下水中。此外，氮肥负责一氧化二氮的产生(农业土壤占总产量的70%)，这对温室气体和酸雨的形成有很大贡献。从经济和环境的角度来看，在保持作物产量的同时减少目前水平的氮肥的使用显然是有价值的。在拟议的工作中，我们计划研究水稻和玉米的氮素利用效率。我们将使用转录本和代谢物图谱来分析它们在不同氮素限制条件下的生长情况。此外，通过前期的工作，我们已经培育出了大量的水稻和玉米转基因品系。我们将继续使用生理、生化、分子和基因组分析来更详细地研究那些具有有趣表型的基因。我们将把这两项工作结合起来，以产生关于更多基因的想法来测试。这些构建物将被转化为水稻(由我们)、玉米(由我们的合作伙伴先正达)和大麦(由Good博士的团队通过省级资助计划)，并对产生的品系在氮素限制条件下的生长改善进行测试。在我们的受控生长设施中，任何在这些条件下生长得到改善的品系都将由我们的合作伙伴先正达进行田间测试，看看它们是否提高了氮素利用效率。最终，这项研究将有助于降低农民的经济成本，有助于减少农业生产对水生生态系统(地表水和地下水)的影响，并减少排放到空气中的一氧化二氮水平。

The use of nitrogenous fertilizers in farming is a large input cost to farmers and has a profound negative impact on the environment. As the price of energy increases the cost of nitrogen fertilizer will also increase as its production involves a process that requires large amounts of energy. High input crops are dependent on the use of nitrogenous fertilizers; however, the majority of the nitrogen from these fertilizers (approximately 70%) is lost as runoff into surface and ground waters. Furthermore, nitrogenous fertilizers are responsible for the production of nitrous oxide (agricultural soils account for 70% of production), which contribute significantly to greenhouse gases and the formation of acid rain. It is clearly valuable from both an economic and environmental point of view to decrease the use of nitrogenous fertilizers from current levels while maintaining crop yields. In the proposed work, we plan on studying nitrogen use efficiency in rice and corn. We will use both transcript and metabolite profiling to analyze their growth under varying nitrogen limitation conditions. In addition, through previous work we have generated a large number of rice and corn transgenic lines. We will continue to study in greater detail those having interesting phenotypes using physiological, biochemical, molecular and genomic analyses. We will combine these two lines of work to generate ideas about additional genes to test. These constructs will be transformed into rice (by us), into corn (by our partners Syngenta) and into barley (by Dr. Good's group through a provincial funding program) and the resulting lines tested for improved growth under nitrogen limitation conditions. Any lines with improved growth under these conditions in our controlled growth facilities will be field tested by our partners Syngenta to see if they have improved nitrogen use efficiency. Ultimately this research will assist in reducing the economic cost to farmers and help reduce the impact of agricultural production on aquatic ecosystems (surface and ground water) and reduce the levels of nitrous oxide being released into the air.