Functional analysis of NLP7 for optimising nitrate responsive growth

植物利用土壤中的养分、阳光中的能量、空气和水来产生生长所需的所有代谢物。反过来，植物直接或间接地提供了人类赖以生存的所有营养物质。从土壤中获取养分需要一种叫做转运蛋白的特殊蛋白质，这种蛋白质可以从土壤中吸收微量的养分。由于土壤成分的变化，植物通过改变养分转运体的水平和活动来调整其生长需求以适应养分的可利用性，这样即使养分水平发生变化，植物的生长也能得到优化。关于控制硝酸盐吸收和利用的机制已经了解了很多，因为它对肥料的施用有关键影响。农作物的高产量严重依赖于施用高水平的肥料，如氮磷钾，以提供主要营养。施用的氮肥中约有三分之一被植物吸收和利用，其余的留在土壤中或被冲进水道，这是一种主要污染物。因此，含硝酸盐肥料的使用受到法律的限制，可能需要进一步减少。然而，许多现代作物品种已经培育出高产以应对高硝酸盐施用。因此，我们需要培育新的作物品种，能够在相对较低的硝酸盐水平下保持高水平的生产力。应对这一挑战的一种方法是准确地了解植物如何对土壤中的硝酸盐水平做出反应，并规划它们的新陈代谢和生长，以吸收和代谢硝酸盐以促进生长。我们最近发现了一种协调这种反应的基因开关。我们已经证明，这种转换需要硝酸盐和糖同时起作用，并且它可能为植物提供一种协调土壤中硝酸盐和光合作用产生的能量和碳水化合物的供应的方法，从而为生长提供营养。在这个研究项目中，我们的目标是以精确的定量方式了解这种开关，然后巧妙地改变组件，看看我们是否可以制造出对硝酸盐和糖水平有不同定量反应的开关。然后，我们将测试这是否会改变植物对硝酸盐和光照水平的生长反应。通过这种方式，拟议的研究将提供新的知识和理解，可用于创造新的作物品种，这些品种可以在减少肥料投入的情况下生长并产生良好的产量。这将有助于为主要作物实现更具环境可持续性的农业生产系统。

Plants use nutrients from the soil, energy from sunlight, and air and water to produce all the metabolites they need for growth. In turn plants provide, directly and indirectly, essentially all of the nutrients that sustain humans. Nutrient acquisition from the soil requires special proteins called transporters that can take up trace levels of nutrients from the soil. Because soil composition varies, plants adapt their growth requirements to nutrient availability by altering the levels and activities of nutrient transporters so that plant growth is optimised even though nutrient levels change. Much has been learnt about the mechanisms involved in controlling nitrate uptake and utilisation for growth because it has a key bearing on the application of fertilisers. The high yields of crops are critically dependent on the application of high levels of fertilisers such as NPK to supply the main nutrients. About 1/3 of applied nitrogenous fertiliser is actually taken up and used by the plant, with the rest remaining bound in the soil or washed away into watercourses, where it is a major pollutant. Consequently the application of nitrate-containing fertilisers is limited by legislation, and may need to be reduced further. However, many modern crop varieties have been bred to produce high yields in response to high nitrate applications. Therefore we need to breed new crop varieties that can maintain high levels of productivity in relatively low nitrate levels. One way of approaching this challenge is to understand precisely how plants respond to nitrate levels in the soil and programme their metabolism and growth to take up and metabolise nitrate for growth. We have recently identified a genetic switch that coordinates this response. We have shown that this switch requires both nitrate and sugars to work, and that it may provide a way for plants to coordinate the supply of nitrate from the soil and energy and carbohydrates from photosynthesis to make nutrients for growth. In this research project we aim to understand this switch in a precise quantitative way, and then to subtly alter components to see if we can make a switch that has different quantitative responses to nitrate and sugar levels. We will then test if this alters plant growth responses to nitrate and illumination levels. In this way the proposed research will provide new knowledge and understanding that can be used to create new crop varieties that can grow and produce good yields from reduced inputs of fertilisers. This will help achieve more environmentally sustainable agricultural production systems for major crops.