Nitrogen (N) is an essential macronutrient that is required for plant growth and development and has a major impact on crop yield and biomass. However, excessive application of N-based fertilizer results in environmental pollution and increases cultivation cost. A significant target of crop biotechnology is to develop crop varieties with improved N use efficiency (NUE), thereby overcoming these issues. While various aspects of plant N uptake and utilization have been studied, many factors that fundamentally affect NUE remain uncharacterized. For example, much remains to be learnt about the genes that determine NUE. One of the significant barriers to studying NUE is the absence of an in vivo N monitoring system. There are currently several methods for measuring plant N status, but they have limitations in terms of screening for NUE mutants and sensitive NUE assessment. Here, we describe strategies for generating and screening mutant pools using N molecular sensors, comprised of the rice genes OsALN and OsUPS1, the expression of which is sensitive to endogenous N status. Forward and reverse genetic approaches using the molecular N sensors will help identify molecular mechanisms underlying NUE.

中文翻译：

---

氮分子传感器及其在筛选与氮利用效率相关的突变体中的应用

氮 (N) 是植物生长和发育所需的必需常量营养素，对作物产量和生物量有重大影响。然而，过量施用氮基肥料会造成环境污染并增加栽培成本。作物生物技术的一个重要目标是开发具有更高氮利用效率 (NUE) 的作物品种，从而克服这些问题。虽然已经研究了植物 N 吸收和利用的各个方面，但许多从根本上影响 NUE 的因素仍未得到表征。例如，关于决定 NUE 的基因还有很多有待了解。研究 NUE 的主要障碍之一是缺乏体内 N 监测系统。目前有几种测量植物氮状态的方法，但它们在筛选 NUE 突变体和敏感的 NUE 评估方面存在局限性。在这里，我们描述了使用 N 分子传感器生成和筛选突变体库的策略，包括水稻基因 OsALN 和 OsUPS1，其表达对内源 N 状态敏感。使用分子 N 传感器的正向和反向遗传方法将有助于确定 NUE 的分子机制。