Characterization of Transformed Arabidopsis with Altered Alternative Oxidase Levels and Analysis of Effects on Reactive Oxygen Species in Tissue1[W]
Characterization of Transformed Arabidopsis with Altered Alternative Oxidase Levels and Analysis of Effects on Reactive Oxygen Species in Tissue1[W]
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DOI：
10.1104/pp.105.070763
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发表时间：
2005-11
期刊：
影响因子：
7.4
通讯作者：
A. L. Umbach;F. Fiorani;J. Siedow
中科院分区：
文献类型：
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作者：
A. L. Umbach;F. Fiorani;J. Siedow
植物线粒体的替代氧化酶（AOX）将电子从泛醌池转移到氧中，没有能量守恒。AOX可以使用超过细胞色素途径容量的还原剂，防止过度还原的泛醌池形成活性氧（ROS），因此可能参与对氧化应激的适应。AOX与线粒体ROS的联系仅在分离的线粒体和悬浮培养细胞中进行了研究。为了研究整个植物的ROS和AOX，我们构建了拟南芥（Arabidopsis thaliana）的转化系：AtAOX1a过表达株、AtAOX1a反义株和突变的、组成活性的AtAOX1a过表达株。在KCN存在的情况下，突变型或野生型AOX过表达者的叶片组织的氧化损伤没有增加，而反义系的损伤水平高于未转化叶片。同样，在KCN处理下，反义根和未转化根（而非过表达根）的ROS产量显著增加。因此，当细胞色素途径被化学抑制时，AOX在叶和根中起作用，就像在悬浮细胞中一样，改善ROS的产生。然而，与悬浮培养细胞相比，在非极限生长条件下，无论转化类型如何，均未检测到所选电子传递组分或氧化应激相关酶的叶片转录物水平发生变化。此外，使用反义线的微阵列研究显示，AOX影响线粒体外，特别是叶绿体和几种碳代谢途径。这些结果说明了将AOX转化研究扩展到整个组织的价值。
The alternative oxidase (AOX) of plant mitochondria transfers electrons from the ubiquinone pool to oxygen without energy conservation. AOX can use reductant in excess of cytochrome pathway capacity, preventing reactive oxygen species (ROS) formation from an over-reduced ubiquinone pool, and thus may be involved in acclimation to oxidative stresses. The AOX connection with mitochondrial ROS has been investigated only in isolated mitochondria and suspension culture cells. To study ROS and AOX in whole plants, transformed lines of Arabidopsis (Arabidopsis thaliana) were generated: AtAOX1a overexpressors, AtAOX1a anti-sense plants, and overexpressors of a mutated, constitutively active AtAOX1a. In the presence of KCN, leaf tissue of either mutant or wild-type AOX overexpressors showed no increase in oxidative damage, whereas anti-sense lines had levels of damage greater than those observed for untransformed leaves. Similarly, ROS production increased markedly in anti-sense and untransformed, but not overexpressor, roots with KCN treatment. Thus, AOX functions in leaves and roots, as in suspension cells, to ameliorate ROS production when the cytochrome pathway is chemically inhibited. However, in contrast with suspension culture cells, no changes in leaf transcript levels of selected electron transport components or oxidative stress-related enzymes were detected under nonlimiting growth conditions, regardless of transformation type. Further, a microarray study using an anti-sense line showed AOX influences outside mitochondria, particularly in chloroplasts and on several carbon metabolism pathways. These results illustrate the value of expanding AOX transformant studies to whole tissues.