Qi Guoxiang, Zhao Xiaoqiang, He Fuqiang, Sun Siqi, Shi Zhenzhen, Niu Yining
State Key Laboratory of Aridland Crop Science, College of Agronomy, Gansu Agricultural University, Lanzhou 730070, China.
Plants (Basel). 2024 Oct 11;13(20):2844. doi: 10.3390/plants13202844.
Salt stress can seriously affect the growth and development of maize ( L.), resulting in a great yield loss. Melatonin (MT), an indole hormone, is a potential enhancer of plant tolerance against salt stress. However, the complex mechanisms of MT application in enhancing maize salt tolerance are still unclear. Herein, three-leaf seedlings of salt-susceptible P138 and its salt-resistant ethyl methane sulfonate (EMS)-104 mutant were cultured with or without 150 μM MT application under 0 and 100 mM NaCO treatments for seven days, to systematically explore the response mechanisms of exogenous MT in improving the salt tolerance of maize. The results showed that salt stress triggered an escalation in reactive oxygen species production, enhanced multiple antioxidant enzymes' activities, impaired cellular membrane permeability, inhibited photosynthetic pigment accumulation, and ultimately undermined the vigor and photosynthetic prowess of the seedlings. While suitable MT application counteracted the detrimental impacts of NaCO on seedlings' growth and photosynthetic capacity, the seedling length and net photosynthetic rate of P138 and EMS-104 were increased by 5.5% and 18.7%, and 12.7% and 54.5%, respectively. Quantitative real-time PCR (qRT-PCR) analysis further showed that MT application activated the expression levels of antioxidant enzyme-related genes (, , , and ) and pigment biosynthesis-related genes ( and ) in both maize seedlings under NaCO stress; they then formed a complex interaction network of gene expression, multiple physiological metabolisms, and phenotype changes to influence the salt tolerance of maize seedlings under MT or NaCO stress. To sum up, these observations underscore that 150 μM MT can alleviate salt injury of maize seedlings, which may provide new insights for further investigating MT regulation mechanisms to enhance maize seedlings' salt resistance.
盐胁迫会严重影响玉米（L.）的生长发育，导致产量大幅损失。褪黑素（MT）作为一种吲哚类激素，是增强植物耐盐性的潜在物质。然而，MT 提高玉米耐盐性的复杂机制仍不清楚。在此，将盐敏感型 P138 及其耐盐甲基磺酸乙酯（EMS）-104 突变体的三叶期幼苗在 0 和 100 mM Na₂CO₃ 处理下，分别进行添加或不添加 150 μM MT 的培养，为期七天，以系统探究外源 MT 提高玉米耐盐性的响应机制。结果表明，盐胁迫引发活性氧产生增加，增强多种抗氧化酶活性，损害细胞膜通透性，抑制光合色素积累，最终削弱幼苗活力和光合能力。而适当施用 MT 可抵消 Na₂CO₃ 对幼苗生长和光合能力的不利影响，P138 和 EMS-104 的幼苗长度和净光合速率分别提高了 5.5%和 18.7%，以及 12.7%和 54.5%。定量实时 PCR（qRT-PCR）分析进一步表明，施用 MT 激活了 Na₂CO₃ 胁迫下两种玉米幼苗中抗氧化酶相关基因（、、、和）以及色素生物合成相关基因（和）的表达水平；它们随后形成了一个基因表达、多种生理代谢和表型变化的复杂相互作用网络，以影响 MT 或 Na₂CO₃ 胁迫下玉米幼苗的耐盐性。综上所述，这些观察结果强调 150 μM MT 可减轻玉米幼苗的盐害，这可能为进一步研究 MT 调控机制以增强玉米幼苗耐盐性提供新的见解。
需注意，原文中部分基因名称未给出具体内容，翻译时保留了原文格式。
