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<p>Drought stress severely impairs wheat growth and metabolic homeostasis, with seedlings being highly sensitive. Exogenous sodium nitroprusside (SNP) enhances plant drought tolerance by boosting antioxidant activity, regulating stomatal movement, and promoting osmolyte accumulation, yet its metabolic mechanism in mediating wheat seedling drought responses remains unclear. Using drought-sensitive Zhoumai 18 and drought-tolerant Zhengmai 1860, we investigated SNP’s alleviating effect on drought stress and its metabolic regulatory mechanism via physiological-biochemical assays and untargeted metabolomics. SNP pretreatment mitigated drought-induced damage in both cultivars: it maintained leaf relative water content, reduced cell membrane permeability, increased proline/soluble sugar accumulation, and enhanced activities of antioxidants. Metabolomic analysis revealed SNP primarily regulated arginine-proline metabolism: it upregulated Δ1-pyrroline-5-carboxylate synthetase (P5CS) and pyrroline-5-carboxylate reductase (P5CR) genes to promote proline synthesis, downregulated proline dehydrogenase (ProDH) to inhibit degradation, and modulated polyamine synthesis-related genes, including ornithine decarboxylase (<i>ODC</i>), arginine decarboxylase (<i>ADC</i>), spermidine synthase (<i>SPDS</i>), and S-adenosylmethionine decarboxylase (<i>SAMDC</i>) genes. Notably, the two cultivars showed distinct metabolic responses to SNP. In Zhengmai 1860, SNP coordinated arginine metabolic flux, prioritizing ornithine toward proline synthesis via enhanced P5CS/P5CR, driving significant proline accumulation. In Zhoumai 18, proline biosynthesis relied on the glutamate pathway, while induced ProDH accelerated degradation, leading to much lower proline levels than Zhengmai 1860. This difference in arginine flux distribution and proline synthesis-degradation balance underlies their divergent drought tolerance. Our study provides new insights into SNP-mediated metabolic regulation in wheat drought responses and a theoretical basis for drought-tolerant wheat breeding targeting arginine-proline metabolism.</p>

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Exogenous Sodium Nitroprusside Enhances Drought Resistance in Wheat Seedlings by Regulating Proline Synthesis via the Arginine Pathway

  • 期刊论文

  • 发表日期：

    2026年5月26日

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  • Ruqing Li,
  • Sixu Jin,
  • Menghan Zhang,
  • Anran Wei,
  • Ruili Xue,
  • Shuhan Cheng,
  • Wenjing Bu,
  • Haifang Jiang,
  • Xueli Qi,
  • Yuexia Wang

摘要

Drought stress severely impairs wheat growth and metabolic homeostasis, with seedlings being highly sensitive. Exogenous sodium nitroprusside (SNP) enhances plant drought tolerance by boosting antioxidant activity, regulating stomatal movement, and promoting osmolyte accumulation, yet its metabolic mechanism in mediating wheat seedling drought responses remains unclear. Using drought-sensitive Zhoumai 18 and drought-tolerant Zhengmai 1860, we investigated SNP’s alleviating effect on drought stress and its metabolic regulatory mechanism via physiological-biochemical assays and untargeted metabolomics. SNP pretreatment mitigated drought-induced damage in both cultivars: it maintained leaf relative water content, reduced cell membrane permeability, increased proline/soluble sugar accumulation, and enhanced activities of antioxidants. Metabolomic analysis revealed SNP primarily regulated arginine-proline metabolism: it upregulated Δ1-pyrroline-5-carboxylate synthetase (P5CS) and pyrroline-5-carboxylate reductase (P5CR) genes to promote proline synthesis, downregulated proline dehydrogenase (ProDH) to inhibit degradation, and modulated polyamine synthesis-related genes, including ornithine decarboxylase (ODC), arginine decarboxylase (ADC), spermidine synthase (SPDS), and S-adenosylmethionine decarboxylase (SAMDC) genes. Notably, the two cultivars showed distinct metabolic responses to SNP. In Zhengmai 1860, SNP coordinated arginine metabolic flux, prioritizing ornithine toward proline synthesis via enhanced P5CS/P5CR, driving significant proline accumulation. In Zhoumai 18, proline biosynthesis relied on the glutamate pathway, while induced ProDH accelerated degradation, leading to much lower proline levels than Zhengmai 1860. This difference in arginine flux distribution and proline synthesis-degradation balance underlies their divergent drought tolerance. Our study provides new insights into SNP-mediated metabolic regulation in wheat drought responses and a theoretical basis for drought-tolerant wheat breeding targeting arginine-proline metabolism.