Melatonin Suppressed the Heat Stress-Induced Damage in Wheat Seedlings by Modulating the Antioxidant Machinery
Melatonin Suppressed the Heat Stress-Induced Damage in Wheat Seedlings by Modulating the Antioxidant Machinery
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褪黑素通过调节抗氧化机制减轻热胁迫对小麦幼苗造成的损伤
DOI：
10.3390/plants9070809
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发表时间：
2020-07-01
期刊：
影响因子：
4.5
通讯作者：
Wang, Chengshe
中科院分区：
文献类型：
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作者：
Buttar, Zeeshan Ali;Wu, Sheng Nan;Wang, Chengshe
褪黑素（n -乙酰-5-甲氧基色胺）是一种多效性信号分子，在调节包括热应激（HS）在内的各种环境胁迫中起着至关重要的作用。本研究发现，在100 μ M褪黑素（MT）预处理后，不同时间的热应激可以通过防止过氧化氢（H2O2）的过度积累、降低脂质过氧化含量（丙二醛（MDA）含量）和增加脯氨酸（Pro）的生物合成来有效减轻氧化应激。此外，小麦幼苗的抗氧化酶，如超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和过氧化物酶（POD）活性显著提高。MT通过调节小麦幼苗抗氧化防御系统，激活抗坏血酸过氧化物酶（APX）组成的抗坏血酸-谷胱甘肽（AsA-GSH）循环，增加谷胱甘肽还原酶（GR）活性，显著提高了小麦幼苗的耐热性。它还通过增加叶绿素含量来保持光合机制的稳定。MT+ hs处理植株的内源MT含量也有所增加。此外，在mt处理的幼苗中，活性氧（ROS）相关基因TaSOD、TaPOD和TaCAT以及抗胁迫应答基因TaMYB80、TaWRKY26和TaWRKY39的表达也被诱导。由于这些显著的变化，与对照相比，mt处理的幼苗的抗逆性有所提高。综上所述，我们的研究结果表明，MT可以通过调节抗氧化防御系统和调节应激反应基因的转录，在提高植物的抗逆性方面发挥关键作用。
Melatonin (N-acetyl-5-methoxytryptamine) is a pleiotropic signaling molecule that plays a crucial role in the regulation of various environmental stresses, including heat stress (HS). In this study, a 100 mu M melatonin (MT) pretreatment followed by exposure to heat stress for different time periods was found to efficiently reduce oxidative stress by preventing the over-accumulation of hydrogen peroxide (H2O2), lowering the lipid peroxidation content (malondialdehyde (MDA) content), and increasing proline (Pro) biosynthesis. Moreover, the activities of antioxidant enzymes, such as superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD), were increased substantially in MT-pretreated wheat seedlings. The presence of MT significantly improved the heat tolerance of wheat seedlings by modulating their antioxidant defense system, activating the ascorbate-glutathione (AsA-GSH) cycle comprising ascorbate peroxidase (APX), and increasing glutathione reductase (GR) activities. It also held the photosynthetic machinery stable by increasing the chlorophyll content. Enhancement in the endogenous MT contents was also observed in the MT+HS-treated plants. Furthermore, the expression of reactive oxygen species (ROS)-related genes TaSOD, TaPOD, and TaCAT, and anti-stress responsive genes, such as TaMYB80, TaWRKY26, and TaWRKY39, was also induced in MT-treated seedlings. Due to these notable changes, an improvement in stress resistance was observed in MT-treated seedlings compared with control. Taken together, our findings suggest that MT can play a key role in boosting the stress tolerance of plants by modulating the antioxidant defense system and regulating the transcription of stress-responsive genes.