Gupta Praveen, Saxena Gauri, Gupta Ravi
Department of Botany, University of Lucknow, Lucknow, Uttar Pradesh 226007, India.
Plant Stress Physiology and Proteomics Laboratory, College of General Education, Kookmin University, Seoul 02707, Republic of Korea.
J Exp Bot. 2025 Aug 6. doi: 10.1093/jxb/eraf353.
Nitrate reductase (NR), a key enzyme in nitrogen metabolism, catalyzes the reductive nitric oxide (NO) production in plants. However, the functional roles of NR and NR-mediated NO evolution in shaping stress adaptation in plants remain largely elusive. In recent years, significant progress has been made in NR research, leading to the identification of (i) specific physiological conditions at which NR-mediated NO production takes place, (ii) signaling proteins associated with the activation of NR, and (iii) various post-translational modifications (PTMs) that affect the activity and stability of NR. Emerging evidence has also revealed dynamic interplay among NO, classical phytohormones, and emerging plant growth regulators (PGRs), which collectively modulate defense responses in plants. Notably, NR-dependent NO plays a pivotal role in maintaining nutrient uptake and reactive oxygen species (ROS) homeostasis under various stress conditions and also contributes to root development, stomatal closure, secondary metabolite biosynthesis, defense gene expression, and hypersensitive response, depending on the specific type of stress to facilitate stress mitigation. The present review provides the recent advancements in the regulation of NR activity, the specific cellular signals involved, and the impact of classical phytohormones and emerging PGRs on NO production to broaden our understanding of the multifaceted role of NR and provide insights into potential strategies for improving crop resilience.
硝酸还原酶（NR）是氮代谢中的关键酶，催化植物中还原性一氧化氮（NO）的产生。然而，NR以及NR介导的NO生成在塑造植物胁迫适应性中的功能作用仍 largely elusive。近年来，NR研究取得了显著进展，导致确定了：（i）NR介导的NO产生发生的特定生理条件；（ii）与NR激活相关的信号蛋白；以及（iii）影响NR活性和稳定性的各种翻译后修饰（PTM）。新出现的证据还揭示了NO、经典植物激素和新兴植物生长调节剂（PGR）之间的动态相互作用，它们共同调节植物中的防御反应。值得注意的是，依赖NR的NO在各种胁迫条件下维持养分吸收和活性氧（ROS）稳态方面起着关键作用，并且还根据特定的胁迫类型促进胁迫缓解，对根系发育、气孔关闭、次生代谢物生物合成、防御基因表达和过敏反应有贡献。本综述介绍了NR活性调节、所涉及的特定细胞信号以及经典植物激素和新兴PGR对NO产生的影响方面的最新进展，以拓宽我们对NR多方面作用的理解，并为提高作物抗逆性的潜在策略提供见解。
