Factors Affecting the Enhancement of Oxidative Stress Tolerance in Transgenic Tobacco Overexpressing Manganese Superoxide Dismutase in the Chloroplasts
Factors Affecting the Enhancement of Oxidative Stress Tolerance in Transgenic Tobacco Overexpressing Manganese Superoxide Dismutase in the Chloroplasts
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DOI：
10.1104/pp.107.3.737
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发表时间：
1995-03
期刊：
影响因子：
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通讯作者：
L. Slooten;K. Capiau;W. V. Camp;M. V. Montagu;Chris Sybesma;Dirk;lnzé
中科院分区：
文献类型：
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作者：
L. Slooten;K. Capiau;W. V. Camp;M. V. Montagu;Chris Sybesma;Dirk;lnzé
以烟草品种PBD 6和SR 1为试材，研究了转锰超氧化物歧化酶（MnSOD）基因烟草的遗传转化。过表达的MnSOD抑制活性的SOD（内源MnSOD和叶绿体和胞质Cu/ZnSOD）是突出的在年轻的叶片，但消失的大部分或完全老化的叶片。转基因植物和对照植物生长在不同的光强度，然后测定氧自由基胁迫的耐受性，在叶盘测定和丰富的抗氧化酶和底物的叶子。转基因植株对甲基紫精（MV）的抗性增强，与对照植株相比，只有在高光强下生长。在这两个品种的FeSOD，抗坏血酸过氧化物酶，脱氢抗坏血酸还原酶，和单脱氢抗坏血酸还原酶的活性和谷胱甘肽和抗坏血酸的浓度（所有表示在叶绿素的基础上）在生长过程中随着光照强度的增加而增加。这些成分中的大多数与MV耐受性相关。有人认为，超氧化物歧化酶的过度表达导致增强的耐受性MV依赖性氧化应激，只有当这些组件中的一个或多个也存在于高水平。此外，结果表明，在变种SR 1的过表达MnSOD增强主要是基质抗氧化系统。
Two varieties of tobacco (Nicotiana tabacum var PBD6 and var SR1) were used to generate transgenic lines overexpressing Mn-superoxide dismutase (MnSOD) in the chloroplasts. The overexpressed MnSOD suppresses the activity of those SODs (endogenous MnSOD and chloroplastic and cytosolic Cu/ZnSOD) that are prominent in young leaves but disappear largely or completely during aging of the leaves. The transgenic and control plants were grown at different light intensities and were then assayed for oxygen radical stress tolerance in leaf disc assays and for abundance of antioxidant enzymes and substrates in leaves. Transgenic plants had an enhanced resistance to methylviologen (MV), compared with control plants, only after growth at high light intensities. In both varieties the activities of FeSOD, ascorbate peroxidase, dehydroascorbate reductase, and monodehydroascorbate reductase and the concentrations of glutathione and ascorbate (all expressed on a chlorophyll basis) increased with increasing light intensity during growth. Most of these components were correlated with MV tolerance. It is argued that SOD overexpression leads to enhancement of the tolerance to MV-dependent oxidative stress only if one or more of these components is also present at high levels. Furthermore, the results suggest that in var SR1 the overexpressed MnSOD enhances primarily the stromal antioxidant system.