Functional analysis of NLP7 for optimising nitrate responsive growth

植物利用土壤中的养分、阳光以及空气和水中的能量来产生生长所需的所有代谢物。反过来，植物直接和间接地提供了基本上所有维持人类生存的营养物质。从土壤中获取养分需要一种名为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。由于土壤成分不同，植物通过改变养分转运体的水平和活动来适应养分的可获得性，从而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促进生长的机制，人们已经了解了很多，因为它对化肥的应用具有关键影响。农作物的高产在很大程度上依赖于高水平化肥的使用，如NPK来提供主要养分。大约三分之一的氮肥实际上被植物吸收和使用，其余的留在土壤中或被冲走进入水道，在那里它是一种主要污染物。因此，含硝酸盐化肥的应用受到立法的限制，可能需要进一步减少。然而，许多现代作物品种已经被培育成能在高硝酸盐施用量下产生高产的品种。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，并对它们的新陈代谢和生长进行编程，以吸收和代谢硝酸盐以促进生长。我们最近发现了一个协调这一反应的基因开关。我们已经证明，这种转换需要硝酸盐和糖的共同作用，而且它可能为植物提供一种方式，以协调来自土壤的硝酸盐和光合作用产生的能量和碳水化合物的供应，从而为生长提供营养。在这个研究项目中，我们的目标是以一种精确的定量方式了解这种变化，然后微妙地改变成分，看看我们是否可以对硝酸盐和糖水平做出不同的定量反应。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化肥投入的情况下生长并产生良好的产量。这将有助于实现主要农作物更具环境可持续性的农业生产体系。

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.