Evidence for a role of salicylic acid in the oxidative damage generated by NaCl and osmotic stress in Arabidopsis seedlings
Evidence for a role of salicylic acid in the oxidative damage generated by NaCl and osmotic stress in Arabidopsis seedlings
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DOI：
10.1104/pp.126.3.1024
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发表时间：
2001-07-01
期刊：
影响因子：
7.4
通讯作者：
Botella, MA
中科院分区：
文献类型：
--
作者：
Borsani, O;Valpuesta, V;Botella, MA
先前的研究表明，水杨酸（CSA）是植物抵抗病原体的重要组成部分。我们现在表明，SA 在植物对不利环境条件（例如盐和渗透胁迫）的反应中发挥着作用。我们研究了野生型拟南芥和表达水杨酸羟化酶 (NahG) 基因的 SA 缺陷转基因株系对不同非生物胁迫条件的反应。野生型植物在中等光照条件下在补充有 100 mM NaCl 或 270 mM 甘露醇的培养基中发芽，在芽中显示出广泛的坏死。相比之下，在相同条件下发芽的 NahG 植物保持绿色并长出真叶。在相同条件下，NahG 幼苗没有观察到坏死，这表明 SA 增强了盐和渗透胁迫期间光合组织中活性氧的产生。该假设得到以下观察结果的支持。首先，除草剂甲基紫精是光合作用过程中超氧自由基的产生剂，仅在野生型植物中产生坏死表型。其次，发芽培养基中活性氧清除化合物的存在逆转了盐和渗透胁迫下观察到的野生型坏死表型。第三，与 NahG 幼苗相比，在 NaCl 胁迫下观察到野生型幼苗中谷胱甘肽库的氧化状态有更大的增加。第四，通过脂质过氧化测量，在 NaCl 胁迫下，与 NahG 幼苗相比，野生型幼苗发生了更大的氧化损伤。我们的数据支持 SA 增强拟南芥幼苗萌发应激反应的模型。
Previous studies have shown that salicylic acid CSA) is an essential component of the plant resistance to pathogens. We now show that SA plays a role in the plant response to adverse environmental conditions, such as salt and osmotic stresses. We have studied the responses of wild-type Arabidopsis and an SA-deficient transgenic line expressing a salicylate hydroxylase (NahG) gene to different abiotic stress conditions. Wild-type plants germinated under moderate light conditions in media supplemented with 100 mM NaCl or 270 mM mannitol showed extensive necrosis in the shoot. In contrast, NahG plants germinated under the same conditions remained green and developed true leaves. The lack of necrosis observed in NahG seedlings under the same conditions suggests that SA potentiates the generation of reactive oxygen species in photosynthetic tissues during salt and osmotic stresses. This hypothesis is supported by the following observations. First, the herbicide methyl viologen, a generator of superoxide radical during photosynthesis, produced a necrotic phenotype only in wild-type plants. Second, the presence of reactive oxygen-scavenging compounds in the germination media reversed the wild-type necrotic phenotype seen under salt and osmotic stress. Third, a greater increase in the oxidized state of the glutathione pool under NaCl stress was observed in wild-type seedlings compared with NahG seedlings. Fourth, greater oxidative damage occurred in wild-type seedlings compared with NahG seedlings under NaCl stress as measured by lipid peroxidation. Our data support a model for SA potentiating the stress response of the germinating Arabidopsis seedling.