title: Changes in hydrogen peroxide homeostasis trigger an active cell death process in tobacco.
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.
authors.affiliation: Department of Plant Systems Biology, Flanders Interuniversity Institute for Biotechnology, Ghent University, K.L. Ledeganckstraat 35, B-9000 Gent, Belgium.
authors.forename: James F
authors.initials: JF
authors.lastname: Dat
authors.forename: Riikka
authors.initials: R
authors.lastname: Pellinen
authors.forename: Tom
authors.initials: T
authors.lastname: Beeckman
authors.forename: Brigitte
authors.initials: B
authors.lastname: Van De Cotte
authors.forename: Christian
authors.initials: C
authors.lastname: Langebartels
authors.forename: Jaakko
authors.initials: J
authors.lastname: Kangasjärvi
authors.forename: Dirk
authors.initials: D
authors.lastname: Inzé
authors.forename: Frank
authors.initials: F
authors.lastname: Van Breusegem
mesh_terms: D017209:Apoptosis / Q000502:physiology*; D002374:Catalase / Q000378:metabolism; D019069:Cell Respiration / Q000502:physiology; D006706:Homeostasis / Q000502:physiology*; D006861:Hydrogen Peroxide / Q000378:metabolism*; D008027:Light; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000502:physiology; D018515:Plant Leaves / Q000502:physiology; D030821:Plants, Genetically Modified; D015398:Signal Transduction / Q000502:physiology; D014026:Nicotiana / Q000235:genetics / Q000502:physiology*
chemical_list: D006861:Hydrogen Peroxide; D002374:Catalase