Nitrogen (N) is an essential macronutrient for plants, and a major limiting factor for plant growth and crop production. Nitrate is the main source of N available for plants in agricultural soils and in many natural environments. Sustaining agricultural productivity is of paramount importance in the current scenario of increasing world population, diversification of crop uses, and climate change. Plant productivity for major crops around the world is still supported by excess application of N-based fertilizers with detrimental economic and environmental impacts. Thus, understanding how plants regulate nitrate uptake and metabolism is key for developing new crops with enhanced N use efficiency (NUE) and to cope with future world food demands. The study of plant responses to nitrate has gained considerable interest over the last thirty years. This review provides an overview of key findings in nitrate research, spanning biochemistry, molecular genetics, genomics and systems biology. We discuss how we reached our current understanding of nitrate transport, local and systemic nitrate sensing/signaling, and the regulatory networks underlying nitrate-controlled outputs in plants. We hope this summary serves not only as a time-line and information repository, but also as a base to outline important open questions for future research.

氮是植物必需的大量营养素，也是植物生长和作物生产的主要限制因素。硝酸盐是农业土壤和许多自然环境中植物可用氮的主要来源。在当前世界人口增加，农作物用途多样化和气候变化的当前情况下，维持农业生产力至关重要。过量施用氮基肥料对全球主要农作物的植物生产力仍然具有不利的经济和环境影响。因此，了解植物如何调节硝酸盐的吸收和代谢对于开发具有更高氮利用效率（NUE）的新作物以及应对未来世界粮食需求至关重要。在过去的三十年中，植物对硝酸盐反应的研究引起了相当大的兴趣。这篇综述概述了硝酸盐研究的主要发现，涵盖了生物化学，分子遗传学，基因组学和系统生物学。我们讨论了如何达到对硝酸盐运输，局部和系统性硝酸盐感应/信号以及植物中硝酸盐控制输出的基础监管网络的当前理解。我们希望该摘要不仅可以作为时间表和信息存储库，而且可以作为概述未来研究的重要开放性问题的基础。