Deciphering components of the nitrogen limitation response in arabidopsis

由于人口的增加、人均作物用量的增加和环境问题，世界范围内的作物生产将受到相当大的压力。 除了水的供应，氮是作物生产的主要限制因素。 为了开发出能够更有效地利用氮的作物，我们必须了解基因型对氮的获取和利用的作用。 因此，有必要了解在氮限制条件下控制氮代谢的信号和调节机制的作用。 在这个建议中，研究将集中在拟南芥的分子遗传学和基因组研究。 首先，我们希望更详细地了解植物如何感受氮限制。 其次，我们希望靶向一组转录因子（GNC和CGA-1），我们有相当多的证据表明它们在氮限制下控制碳氮平衡的作用。 此外，这些基因的过表达可导致拟南芥和水稻中生长表型增强。 我们确定了氮限制适应性（nla）基因作为一个关键组成部分的拟南芥植物生长在有限的氮条件下的适应。我们将使用各种技术，包括遗传学，生物化学和生理学方法，以确定额外的基因是氮限制适应性途径所必需的。 此外，我们将描绘GNC和CGA-1转录因子的靶点，这将使我们能够进一步了解它们的作用。 最后，我们将做一个代谢组和转录组分析的响应拟南芥限制氮在野生型和各种突变体和过度表达线，我们已经开发或将在未来开发。 长期目标是利用这些信息来靶向作物中的基因，以开发在使用较少氮肥的田间条件下产量更高的遗传品系。 这反过来将大大提高作物生产的经济和环境可持续性。

Considerable stress will be placed on world-wide crop production due to an increased human population, an increase in the crops used per person and environmental issues. Besides water availability, nitrogen is the major limiting factor in crop production. To develop crops that can use nitrogen more efficiently, we must understand the role of genotype on its acquisition and use. Therefore, it is essential to understand the role of signaling and regulatory mechanisms that control nitrogen metabolism under nitrogen limitation conditions. In this proposal, the studies will focus on molecular genetic and genomic studies in Arabidopsis. First, we wish to understand in much greater detail how a plant senses nitrogen limitation. Second, we wish to target a set of transcription factors (GNC and CGA-1) for which we have considerable evidence for their role in controlling the carbon-nitrogen balance under nitrogen limitation. Further, over-expression of these genes can lead to an enhanced growth phenotype in Arabidopsis and rice. We identified the nitrogen limitation adaptability (nla) gene as a key component for the adaptation of Arabidopsis plant grown under limited nitrogen conditions. We will use a variety of techniques including genetic, biochemical and physiological approaches to identify additional genes that are essential for the nitrogen limitation adaptability pathway. In addition, we will delineate the targets of GNC and CGA-1 transcription factors that will allow us to further understand their roles. Finally, we will do a metabolome and transcriptome analysis of the response of Arabidopsis to limiting nitrogen both in wild-type and in the various mutant and over-expression lines that we have developed or will develop in the future. The long term goal is to use this information to target genes in crop plants to develop genetic lines that yield better under field conditions where less nitrogen fertilizer is used. This, in turn, would significantly improve both the economic and environmental sustainability of crop production.