MOE Key Laboratory of Environment Remediation and Ecological Health, College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, China.
Zhejiang Provincial Cultivated Land Quality and Fertilizer Administration Station, Hangzhou, China.
J Pineal Res. 2020 May;68(4):e12642. doi: 10.1111/jpi.12642. Epub 2020 Mar 25.
Melatonin is a universal regulator modulating plant development and responses to abiotic stresses. The alteration and potential roles of melatonin in mediating aluminum (Al) tolerance were investigated in two wheat genotypes differing in Al resistance. Using the high-resolution mass spectrometry, we observed that melatonin contents in Xi Aimai-1 were 1.7-fold higher than that in Yangmai-5. Application of melatonin conferred Al resistance in both genotypes. Melatonin treatment scavenged reactive oxygen species (ROS) accumulation and alleviated Al-induced oxidative damage to lipids and proteins by stimulating antioxidant enzymes and augmenting antioxidants. Additionally, melatonin treatment decreased root tip-Al contents by 19.0% and 15.5% in Xi Aimai-1 and Yangmai-5, respectively. Malate efflux, however, was not altered by melatonin under Al stress. The amount of cell wall polysaccharide and pectin methylesterase activity was significantly increased by Al treatment; but suppressed by melatonin. Melatonin synthesis inhibitor, p-CPA, significantly increased the amount of the Al binding in cell walls of the tolerant genotype, whereas exogenous melatonin decreased cell wall Al content in the sensitive genotype. These results suggest that melatonin alleviated Al toxicity through augmenting antioxidants and inducing antioxidant enzymes to control ROS and enhancing exclusion of Al from root apex by altering cell wall polysaccharides in wheat.
褪黑素是一种普遍的调节剂，可调节植物的发育和对非生物胁迫的反应。本研究在两种耐铝性不同的小麦基因型中，研究了褪黑素在介导铝（Al）耐受性中的变化及其潜在作用。利用高分辨率质谱法，我们观察到，在 Xi Aimai-1 中，褪黑素含量是 Yangmai-5 的 1.7 倍。褪黑素处理可赋予两种基因型的耐铝性。褪黑素处理通过刺激抗氧化酶和增加抗氧化剂来清除活性氧（ROS）的积累并减轻 Al 诱导的脂质和蛋白质氧化损伤。此外，褪黑素处理分别使 Xi Aimai-1 和 Yangmai-5 的根尖 Al 含量降低了 19.0%和 15.5%。然而，在 Al 胁迫下，褪黑素处理并没有改变苹果酸的外排。Al 处理显著增加了细胞壁多糖和果胶甲酯酶活性的含量；但被褪黑素抑制。褪黑素合成抑制剂 p-CPA 显著增加了耐铝基因型细胞壁中 Al 的结合量，而外源性褪黑素则降低了敏感基因型的细胞壁 Al 含量。这些结果表明，褪黑素通过增强抗氧化剂和诱导抗氧化酶来控制 ROS，以及通过改变细胞壁多糖来增强 Al 从根尖的排除，从而缓解 Al 毒性。
