Li Yan, Sun Yan, Cui Huiting, Li Mingna, Yang Guofeng, Wang Zengyu, Zhang Kun
Key Laboratory of National Forestry and Grassland Administration on Grassland Resources and Ecology in the Yellow River Delta, College of Grassland Science, Qingdao Agricultural University, Qingdao, China.
College of Grassland Science and Technology, China Agricultural University, Beijing, China.
Front Plant Sci. 2022 Aug 10;13:971431. doi: 10.3389/fpls.2022.971431. eCollection 2022.
Melatonin is an important, multifunctional protective agent against a variety of abiotic and biotic stressors in plants. Caffeic acid O-methyltransferase (COMT) catalyzes the last step of melatonin synthesis in plants and reportedly participates in the regulation of stress response and tolerance. However, few studies have reported its function in melatonin-mediated drought resistance. In this study, was identified and was strongly induced by drought stress in . overexpression in transgenic tobacco increased tolerance to drought stress with high levels of seed germination, relative water content, and survival rates. overexpression in tobacco improved membrane stability, and plants exhibited lower relative electrolytic leakage and malondialdehyde content, as well as higher photochemical efficiency than the wildtype (WT) under drought stress. The transgenic plants also had higher levels of proline accumulation and antioxidant enzyme activity, which decreased oxidative stress damage due to reactive oxygen species (ROS) hyperaccumulation under drought stress. The transcription of drought stress response and ROS scavenging genes was significantly higher in the overexpression plants than in the WT plants. In addition, transgenic tobacco plants exhibited higher melatonin content under drought stress conditions. Exogenous melatonin was applied to under drought stress to confirm the function of melatonin in mediating drought tolerance; the relative water content and proline content were higher, and the relative electrolytic leakage was lower in melatonin-treated than in the untreated plants. In summary, these results show that plays a positive role in plant drought stress tolerance by regulating endogenous melatonin content.
褪黑素是植物抵御各种非生物和生物胁迫的一种重要的多功能保护剂。咖啡酸O-甲基转移酶（COMT）催化植物褪黑素合成的最后一步，据报道参与胁迫反应和耐受性的调节。然而，很少有研究报道其在褪黑素介导的抗旱性中的功能。在本研究中，[具体基因名称未给出]被鉴定出来，并且在[具体植物名称未给出]中受干旱胁迫强烈诱导。在转基因烟草中过表达[具体基因名称未给出]可提高对干旱胁迫的耐受性，具有高水平的种子萌发率、相对含水量和存活率。在烟草中过表达[具体基因名称未给出]可改善膜稳定性，与野生型（WT）相比，在干旱胁迫下植物表现出较低的相对电解质渗漏率和丙二醛含量，以及较高的光化学效率。转基因植物还具有更高水平的脯氨酸积累和抗氧化酶活性，这减少了干旱胁迫下由于活性氧（ROS）过度积累导致的氧化应激损伤。在过表达[具体基因名称未给出]的植物中，干旱胁迫响应和ROS清除基因的转录显著高于WT植物。此外，在干旱胁迫条件下，[具体基因名称未给出]转基因烟草植物表现出更高的褪黑素含量。在干旱胁迫下，将外源褪黑素应用于[具体植物名称未给出]以证实褪黑素在介导耐旱性中的功能；与未处理的植物相比，褪黑素处理的[具体植物名称未给出]相对含水量和脯氨酸含量更高，相对电解质渗漏率更低。总之，这些结果表明[具体基因名称未给出]通过调节内源性褪黑素含量在植物干旱胁迫耐受性中发挥积极作用。
