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Molecular Mechanisms of Tolerance to Reactive Oxygen Species and Its Induction in Weeds

杂草对活性氧的耐受及其诱导的分子机制

基本信息

批准号：
15380011
负责人：
MATSUMOTO Hiroshi
金额：
$ 4.99万
依托单位：
University of Tsukuba
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15380011/
关键词：
weeds tolerance to photooxidative stress reactive oxygen species anti-oxidative enzyme activity gene of antioxidative enzymes peroxidation of membrane chloroplast ESR analysis 膜の過酸化障害

项目摘要

This study was aimed to elucidate physiological and molecular mechanisms of tolerance of plants including weeds to environmental stress especially to photo-oxidative injury caused by natural and synthetic chemicals.Leguminous weed Sesbania rostrata has tolerance to 0.5% NaCl. S.rostrata actively absorbed Na and Cl ions from roots and translocated them to aboveground parts. Therefore, mechanisms of stress alleviation in shoot cells of this species were investigated. High concentrations of the ions increased the production of reactive oxygen species (ROS) in the cells. S.rostrata has higher constitutive levels of antioxidative enzymes and these enzyme activities were remarkably induced by the salt-stress.Plant species grown with magnesium-deficient condition showed greater tolerance to ROS with increased antioxidative enzyme activities especially cytosolic isoform of ascorbate peroxidase. Induction mechanism of this gene is under examination.The mode of actions of the chemicals that caused the peroxidation injury of the cells in the light and the mechanism of tolerance were investigated. To clarify ROS involvement in phytotoxic action of herbicide quinclorac, quantification methods of H_2O_2 has been established. Since ROS has very high reactivity, identification of ROS species is difficult. However, we succeeded H_2O_2 determination with the chemiluminescent method in specific plant species. We also studied ROS identification in plant cells by using ESR.Leguminous allelopathic plant Mucuna pruriens produces L-DOPA. This compound was elucidated to cause oxidative injury on susceptibel plant spesies by ROS generated from melanin synthesis pathway. Selective action of L-DOPA between plant species is due to differential activity of polyphenol oxidase that is responsible for ROS generation.

本研究旨在阐明包括杂草在内的植物对环境胁迫特别是天然和合成化学物质引起的光氧化损伤的生理和分子机制。豆科杂草田菁耐0.5% NaCl。玫瑰草积极吸收根系中的Na和Cl离子，并将其转移到地上部分。因此，本文对该植物茎部细胞的应激缓解机制进行了研究。高浓度的离子增加了细胞中活性氧（ROS）的产生。盐胁迫显著提高了牛蒡的抗氧化酶组成水平。缺镁条件下生长的植物对活性氧的耐受性增强，抗氧化酶活性特别是抗坏血酸过氧化物酶胞质异构体活性增加。该基因的诱导机制正在研究中。研究了光致细胞过氧化损伤的化学物质的作用方式和耐受性机制。为明确活性氧参与除草剂喹诺啉的植物毒性作用，建立了H_2O_2的定量测定方法。由于活性氧具有很高的反应活性，因此很难鉴定活性氧的种类。然而，我们成功地用化学发光法测定了特定植物中H_2O_2的含量。我们还利用ESR技术研究了植物细胞中ROS的鉴定。豆科化感植物Mucuna pruriens产生左旋多巴。该化合物通过黑色素合成途径产生的ROS对敏感植物产生氧化损伤。L-DOPA在植物物种之间的选择性作用是由于多酚氧化酶的活性差异，多酚氧化酶负责ROS的产生。