title: Transgenic tomatoes showing higher glutathione peroxydase antioxidant activity are more resistant to an abiotic stress but more susceptible to biotic stresses.
abstract: The function of selenium independent glutathione peroxidase (GPx) in response to biotic and abiotic stresses was investigated in transgenic tomato plants overexpressing an exogenous GPx and exhibiting a 50% increase in total GPx activity. GPx-overexpressing and control plants were challenged either by a mechanical stress or by infection with the biotrophic parasite Oidium neolycopersici or the necrotrophic parasite Botrytis cinerea. In mechanically stressed plants, internode growth was significantly less modified in GPx-overexpressing plants compared to controls. This stress resistant phenotype was not accompanied with any change in the global antioxidant response of the plants other than their increased GPx activity. Following infection by O. neolycopersici or by B. cinerea, lesion extension was increased in GPx-overexpressing plants compared with controls. These results showed that GPx overexpression provoked opposite effects in situations of biotic and abiotic challenges, suggesting a key role for this scavenger enzyme in controlling biotic and abiotic stress responses.
authors.affiliation: Clermont Université, Université Blaise Pascal, UMRA 547 PIAF, BP 10448, F-63000 Clermont-Ferrand Cedex, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Herbette
authors.forename: Denis Tourvieille
authors.initials: DT
authors.lastname: de Labrouhe
authors.forename: Joël R
authors.initials: JR
authors.lastname: Drevet
authors.forename: Patricia
authors.initials: P
authors.lastname: Roeckel-Drevet
mesh_terms: D000222:Adaptation, Physiological; D000975:Antioxidants / Q000378:metabolism*; D001203:Ascomycota; D020171:Botrytis; D005979:Glutathione Peroxidase / Q000235:genetics / Q000378:metabolism*; D018551:Solanum lycopersicum / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D010935:Plant Diseases / Q000382:microbiology; D057865:Plant Immunity; D018547:Plant Stems / Q000254:growth & development; D030821:Plants, Genetically Modified / Q000201:enzymology; D013314:Stress, Mechanical; D013312:Stress, Physiological
chemical_list: D000975:Antioxidants; D005979:Glutathione Peroxidase