Catalase is a sink for H2O2 and is indispensable for stress defence in C3 plants
Catalase is a sink for H2O2 and is indispensable for stress defence in C3 plants
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DOI：
10.1093/emboj/16.16.4806
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发表时间：
1997-08
期刊：
影响因子：
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通讯作者：
H. Willekens;S. Chamnongpol;M. Davey;M. Schraudner;C. Langebartels;M. Van Montagu;D. Inzé;W. Van Camp-W.
中科院分区：
文献类型：
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作者：
H. Willekens;S. Chamnongpol;M. Davey;M. Schraudner;C. Langebartels;M. Van Montagu;D. Inzé;W. Van Camp-W.
过氧化氢（H2O2）与许多强制降解条件有关。H2O2水平的控制是复杂的，解剖产生和缓解H2O2胁迫的机制是困难的，特别是在完整的植物。我们已经使用具有超过10%野生型过氧化氢酶活性的转基因烟草来研究过氧化氢酶的作用和H2O2胁迫对植物的影响。过氧化氢酶缺乏的植物在低光下没有表现出可见的病症，但在强光下，叶片上迅速出现白色坏死病变。病变的形成需要光呼吸活动，因为在CO2浓度升高的情况下可以防止损伤。在叶片坏死过程中没有检测到H2O2的积累。替代的H2O2清除机制可能补偿了过氧化氢酶活性的降低，如抗坏血酸过氧化物酶和谷胱甘肽过氧化物酶水平的增加所示。叶片坏死与氧化型谷胱甘肽的积累和抗坏血酸的4倍减少相关，表明过氧化氢酶对于维持氧化应激期间的氧化还原平衡至关重要。这种控制可能不限于过氧化物酶体H2O2的产生。过氧化氢酶作为H2O2的细胞库发挥作用，如通过外源过氧化氢酶对过氧化氢酶缺乏的补充以及过氧化氢酶缺乏和对照叶盘在去除外部H2O2方面的比较所证明的。胁迫分析表明，缺乏过氧化氢酶的植物对百草枯、盐和臭氧的敏感性增加，但对低温的敏感性没有增加。
Hydrogen peroxide (H2O2) has been implicated in many stress conditions. Control of H2O2 levels is complex and dissection of mechanisms generating and relieving H2O2 stress is difficult, particularly in intact plants. We have used transgenic tobacco with ∼10% wild‐type catalase activity to study the role of catalase and effects of H2O2 stress in plants. Catalase‐deficient plants showed no visible disorders at low light, but in elevated light rapidly developed white necrotic lesions on the leaves. Lesion formation required photorespiratory activity since damage was prevented under elevated CO2. Accumulation of H2O2 was not detected during leaf necrosis. Alternative H2O2‐scavenging mechanisms may have compensated for reduced catalase activity, as shown by increased ascorbate peroxidase and glutathione peroxidase levels. Leaf necrosis correlated with accumulation of oxidized glutathione and a 4‐fold decrease in ascorbate, indicating that catalase is critical for maintaining the redox balance during oxidative stress. Such control may not be limited to peroxisomal H2O2 production. Catalase functions as a cellular sink for H2O2, as evidenced by complementation of catalase deficiency by exogenous catalase, and comparison of catalase‐deficient and control leaf discs in removing external H2O2. Stress analysis revealed increased susceptibility of catalase‐deficient plants to paraquat, salt and ozone, but not to chilling.