Salt stress-induced programmed cell death in tobacco protoplasts is mediated by reactive oxygen species and mitochondrial permeability transition pore status
Salt stress-induced programmed cell death in tobacco protoplasts is mediated by reactive oxygen species and mitochondrial permeability transition pore status
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DOI：
10.1016/j.jplph.2005.06.016
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发表时间：
2006-05-01
影响因子：
4.3
通讯作者：
Wang, Genxuan
中科院分区：
文献类型：
--
作者：
Lin, Jiusheng;Wang, Yuan;Wang, Genxuan
线粒体通透性转换孔（PTP）的状态和活性氧（ROS）的水平在动物细胞凋亡的调控中起着关键作用。为了研究盐胁迫诱导烟草（Nicotiana tobacum，品种BY-2）原生质体程序性细胞死亡（PCD）过程中PTP和细胞氧化还原状态的变化，采用流式细胞仪同时检测了盐胁迫诱导烟草原生质体程序性细胞死亡（PCD）、PTP和ROS水平。ROS增加，线粒体减少。在PCD出现之前观察膜电位（Δ Psi（m））。用PTP开放抑制剂CsA（cyclosporin A）预处理可有效地延缓PCD的发生，降低Δ Psi（m），增加ROS含量。在盐胁迫期间添加抗坏血酸（阿萨）显著降低了经历PCD的原生质体的百分比和ROS水平，但增加了Δ Psi（m）。过氧化氢有效地诱导PCD的出现，并引起ROS的增加和Δ Psi（m）的降低。用CsA预处理原生质体可减弱H_2O_2的影响。以上结果表明，盐胁迫诱导烟草原生质体细胞程序性死亡过程中，PTP和ROS的开放状态是必需的。PTIP和ROS的开放状态可以相互促进，提示ROS可能导致自放大过程。这一正反馈回路可能是一个全有或全无的开关，这与PTP是动物和植物PCD的重要协调者和执行者的假设是一致的。(c)2005年Elsevier GmbH。All rights reserved.
The status of mitochondrial permeability transition pore (PTP) and levels of reactive oxygen species (ROS) play key roles in regulating apoptosis in animal cells. To investigate if the PTP and cellular oxidation-reduction state are also involved in salt stress-induced programmed cell death (PCD) in tobacco (Nicotiana tobacum, cultivar BY-2) protoplasts, flow cytometry was used to simultaneously monitor ROS levels, PTP status and PCD. Increased ROS and decreased mitochondrial. membrane potential (Delta Psi(m)) were observed before the appearance of PCD. Pre-treatment with an inhibitor of the PTP opening, cyclosporin A (CsA), effectively retarded the onset of PCD, the Delta Psi(m) decrease and the ROS content increase. Addition of ascorbic acid (AsA) during the salt stress significantly decreased the percentage of protoplasts undergoing PCD and ROS levels but increased Delta Psi(m). Hydrogen peroxide effectively induced the appearance of PCD and caused an increase in ROS and a decrease in Delta Psi(m). Pretreatment of protoplasts with CsA weakened the effects of H2O2. All these results suggest that the open state of PTP and ROS are necessary elements for salt stress-induced PCD in tobacco protoplasts. The open states of PTIP and ROS could promote each other suggesting that ROS could Lead to a self-amplifying process. This positive feedback loop may act as an all-or-nothing switch, which is in good accordance with the hypothesis that PTP is an important coordinator and executioner of PCD in both animals and plants. (c) 2005 Elsevier GmbH. All rights reserved.