Mitochondrial complex II has a key role in mitochondrial-derived reactive oxygen species influence on plant stress gene regulation and defense
Mitochondrial complex II has a key role in mitochondrial-derived reactive oxygen species influence on plant stress gene regulation and defense
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DOI：
10.1073/pnas.1016060108
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发表时间：
2011-06-28
影响因子：
11.1
通讯作者：
Singh, Karam B.
中科院分区：
文献类型：
--
作者：
Gleason, Cynthia;Huang, Shaobai;Singh, Karam B.
线粒体既是ATP的来源，又是活性氧（ROS）产生的场所。然而，很少有关于线粒体活性氧（mROS）生产的网站或这样的mROS在植物中的生物学作用的信息。我们提供的遗传证据表明，线粒体复合物II（复合物II）的电子传递链有助于本地化的mROS，调节植物的胁迫和防御反应。我们通过筛选缺乏GSTF 8基因表达的突变体来识别复合物II亚基中的拟南芥突变体，SDH 1 -1。GSTF 8是一个早期胁迫响应基因，其转录受生物和非生物胁迫诱导，其表达通常被用作早期胁迫和防御反应的标记。对这种突变体的转录分析表明，它改变了SA介导的特定下游应激和防御基因的基因表达，并表现出对特定真菌和细菌病原体的易感性增加。dsr 1突变体还显示出显著降低的琥珀酸脱氢酶活性。使用体内荧光测定，我们证明，根细胞活性氧的生产主要发生在线粒体和较低的突变体响应SA。此外，叶片活性氧的产生较低的突变体无毒细菌感染后。这种突变位于SDH 1 -1的保守区域，是一种独特的植物线粒体突变体，其表现出与降低mROS产生相关的表型。它提供了关键的洞察复杂II功能与理解复杂II的线粒体疾病在真核生物的作用的影响。
Mitochondria are both a source of ATP and a site of reactive oxygen species (ROS) production. However, there is little information on the sites of mitochondrial ROS (mROS) production or the biological role of such mROS in plants. We provide genetic proof that mitochondrial complex II (Complex II) of the electron transport chain contributes to localized mROS that regulates plant stress and defense responses. We identify an Arabidopsis mutant in the Complex II subunit, SDH1-1, through a screen for mutants lacking GSTF8 gene expression in response to salicylic acid (SA). GSTF8 is an early stress-responsive gene whose transcription is induced by biotic and abiotic stresses, and its expression is commonly used as a marker of early stress and defense responses. Transcriptional analysis of this mutant, disrupted in stress responses 1 (dsr1), showed that it had altered SA-mediated gene expression for specific downstream stress and defense genes, and it exhibited increased susceptibility to specific fungal and bacterial pathogens. The dsr1 mutant also showed significantly reduced succinate dehydrogenase activity. Using in vivo fluorescence assays, we demonstrated that root cell ROS production occurred primarily from mitochondria and was lower in the mutant in response to SA. In addition, leaf ROS production was lower in the mutant after avirulent bacterial infection. This mutation, in a conserved region of SDH1-1, is a unique plant mitochondrial mutant that exhibits phenotypes associated with lowered mROS production. It provides critical insights into Complex II function with implications for understanding Complex II's role in mitochondrial diseases across eukaryotes.