Department of Biology, Dalhousie University, 1355 Oxford Street, Halifax, NS B3H4J1, Canada.
Planta. 2011 Feb;233(2):407-21. doi: 10.1007/s00425-010-1304-9. Epub 2010 Nov 10.
Within plant systems, two main forms of programmed cell death (PCD) exist: developmentally regulated and environmentally induced. The lace plant (Aponogeton madagascariensis) naturally undergoes developmentally regulated PCD to form perforations between longitudinal and transverse veins over its leaf surface. Developmental PCD in the lace plant has been well characterized; however, environmental PCD has never before been studied in this plant species. The results presented here portray heat shock (HS) treatment at 55 °C for 20 min as a promising inducer of environmental PCD within lace plant protoplasts originally isolated from non-PCD areas of the plant. HS treatment produces cells displaying many characteristics of developmental PCD, including blebbing of the plasma membrane, increased number of hydrolytic vesicles and transvacuolar strands, nuclear condensation, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling positive nuclei, as well as increased Brownian motion within the vacuole. Results presented here for the first time provide evidence of chloroplasts in the vacuole of living protoplasts undergoing environmentally induced PCD. Findings suggest that the mitochondria play a critical role in the cell death process. Changes in mitochondrial dynamics were visualized in HS-treated cells, including loss of mitochondrial mobility, reduction in ΔΨ(m), as well as the proximal association with chloroplasts. The role of the mitochondrial permeability transition pore (PTP) was examined by pre-treatment with the PTP agonist cyclosporine A. Overall, HS is depicted as a reliable method to induce PCD within lace plant protoplasts, and proves to be a reliable technique to enable comparisons between environmentally induced and developmentally regulated PCD within one species of plant.
在植物系统中，存在两种主要形式的程序性细胞死亡（PCD）：发育调控和环境诱导。 lace 植物（Aponogeton madagascariensis）自然经历发育调控的 PCD，在其叶片表面的纵向和横向叶脉之间形成穿孔。 lace 植物中的发育性 PCD 已经得到了很好的描述；然而，在这种植物物种中，环境 PCD 从未被研究过。这里呈现的结果表明，55°C 热休克（HS）处理 20 分钟是 lace 植物原代质体中环境 PCD 的有前途诱导剂，这些质体最初分离自植物非 PCD 区域。HS 处理产生显示出许多发育性 PCD 特征的细胞，包括质膜起泡、水解小泡和跨液泡链的数量增加、核浓缩、末端脱氧核苷酸转移酶介导的 dUTP 缺口末端标记阳性核以及液泡内布朗运动增加。这里呈现的结果首次提供了在活质体中叶绿体经历环境诱导的 PCD 的证据。研究结果表明，线粒体在细胞死亡过程中发挥关键作用。在 HS 处理的细胞中观察到线粒体动力学的变化，包括线粒体迁移性丧失、ΔΨ(m)减少以及与叶绿体的近端关联。通过预先用线粒体通透性转换孔（PTP）激动剂环孢素 A 处理来检查线粒体 PTP 的作用。总体而言，HS 被描绘为在 lace 植物质体中诱导 PCD 的可靠方法，并被证明是一种可靠的技术，可在同一植物物种中比较环境诱导和发育调控的 PCD。
