Plants adapt to changing environmental conditions by adjusting their growth physiology. Nitrate (NO3-) and ammonium (NH4+) are the major inorganic nitrogen forms for plant uptake. However, high NH4+ inhibits plant growth, and roots undergo striking changes, such as inhibition of cell expansion and division, leading to reduced root elongation. In this work, we show that high NH4+ modulates nitrogen metabolism and root developmental physiology by inhibiting iron (Fe)-dependent Jasmonate (JA) signaling and response in Arabidopsis (Arabidopsis thaliana). Transcriptomic data suggested that NH4+ availability regulates Fe and JA-responsive genes. High NH4+ levels led to enhanced root Fe accumulation, which impaired nitrogen balance and growth by suppressing JA biosynthesis and signaling response. Integrating pharmacological, physiological, and genetic experiments revealed the involvement of NH4+ and Fe-derived responses in regulating root growth and nitrogen metabolism through modulation of the JA pathway during NH4+ stress. The JA signaling transcription factor MYC2 directly bound the promoter of the NITRATE TRANSPORTER 1.1 (NRT1.1) and repressed it to optimize the NH4+/Fe-JA balance for plant adaptation during NH4+ stress. Our findings illustrate the intricate balance between nutrient and hormone-derived signaling pathways that appear essential for optimizing plant growth by adjusting physiological and metabolic responses during NH4+/Fe stress.

中文翻译：

---

茉莉酸信号通过抑制铵胁迫期间铁的积累来调节根系生长


植物通过调整其生长生理来适应不断变化的环境条件。硝酸盐 (NO3-) 和铵 (NH4+) 是植物吸收的主要无机氮形式。然而，高NH4+会抑制植物生长，根部会发生显着变化，例如抑制细胞扩张和分裂，导致根部伸长减少。在这项工作中，我们发现高 NH4+ 通过抑制拟南芥 (Arabidopsis thaliana) 中铁 (Fe) 依赖性茉莉酸 (JA) 信号和反应来调节氮代谢和根发育生理学。转录组数据表明 NH4+ 的可用性调节 Fe 和 JA 响应基因。高 NH4+ 水平导致根部 Fe 积累增加，从而抑制 JA 生物合成和信号反应，从而损害氮平衡和生长。综合药理学、生理学和遗传实验揭示了 NH4+ 和 Fe 衍生反应在 NH4+ 胁迫期间通过调节 JA 途径参与调节根生长和氮代谢。 JA 信号转录因子 MYC2 直接结合硝酸盐转运蛋白 1.1 (NRT1.1) 的启动子并对其进行抑制，以优化 NH4+/Fe-JA 平衡，以适应 NH4+ 胁迫期间的植物适应。我们的研究结果说明了营养和激素衍生信号通路之间的复杂平衡，这对于通过在 NH4+/Fe 胁迫期间调整生理和代谢反应来优化植物生长至关重要。