Changes in hydrogen peroxide homeostasis trigger an active cell death process in tobacco

Plant J. 2003 Feb;33(4):621-32. doi: 10.1046/j.1365-313x.2003.01655.x.

Abstract

In transgenic tobacco plants with reduced catalase activity, high levels of hydrogen peroxide (H2O2) can accumulate under photorespiratory conditions. Such a perturbation in H2O2 homeostasis induced cell death in clusters of palisade parenchyma cells, primarily along the veins. Ultrastructural alterations, such as chromatin condensation and disruption of mitochondrial integrity, took place before cell death. Furthermore, enhanced transcript levels of mitochondrial defense genes accompanied these mitochondrial changes. Pharmacological data indicated that the initiation and execution of cell death require de novo protein synthesis and that the signal transduction pathway leading to cell death involved changes in ion homeostasis, (de)phosphorylation events and an oxidative burst, as observed during hypersensitive responses. This oxidase-dependent oxidative burst is essential for cell death, but it is not required for the accumulation of defense proteins, suggesting a more prominent role for the oxidative burst in abiotic stress-induced cell death.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis / physiology*
  • Catalase / metabolism
  • Cell Respiration / physiology
  • Homeostasis / physiology*
  • Hydrogen Peroxide / metabolism*
  • Light
  • Oxidation-Reduction
  • Oxidative Stress / physiology
  • Plant Leaves / physiology
  • Plants, Genetically Modified
  • Signal Transduction / physiology
  • Tobacco / genetics
  • Tobacco / physiology*

Substances

  • Hydrogen Peroxide
  • Catalase