title: The cellular redox state as a modulator in cadmium and copper responses in Arabidopsis thaliana seedlings.
abstract: The cellular redox state is an important determinant of metal phytotoxicity. In this study we investigated the influence of cadmium (Cd) and copper (Cu) stress on the cellular redox balance in relation to oxidative signalling and damage in Arabidopsis thaliana. Both metals were easily taken up by the roots, but the translocation to the aboveground parts was restricted to Cd stress. In the roots, Cu directly induced an oxidative burst, whereas enzymatic ROS (reactive oxygen species) production via NADPH oxidases seems important in oxidative stress caused by Cd. Furthermore, in the roots, the glutathione metabolism plays a crucial role in controlling the gene regulation of the antioxidative defence mechanism under Cd stress. Metal-specific alterations were also noticed with regard to the microRNA regulation of CuZnSOD gene expression in both roots and leaves. The appearance of lipid peroxidation is dual: it can be an indication of oxidative damage as well as an indication of oxidative signalling as lipoxygenases are induced after metal exposure and are initial enzymes in oxylipin biosynthesis. In conclusion, the metal-induced cellular redox imbalance is strongly dependent on the chemical properties of the metal and the plant organ considered. The stress intensity determines its involvement in downstream responses in relation to oxidative damage or signalling.
authors.affiliation: Centre for Environmental Sciences, Environmental Biology, Hasselt University, Diepenbeek, Belgium. ann.cuypers@uhasselt.be
authors.forename: Ann
authors.initials: A
authors.lastname: Cuypers
authors.forename: Karen
authors.initials: K
authors.lastname: Smeets
authors.forename: Jos
authors.initials: J
authors.lastname: Ruytinx
authors.forename: Kelly
authors.initials: K
authors.lastname: Opdenakker
authors.forename: Els
authors.initials: E
authors.lastname: Keunen
authors.forename: Tony
authors.initials: T
authors.lastname: Remans
authors.forename: Nele
authors.initials: N
authors.lastname: Horemans
authors.forename: Nathalie
authors.initials: N
authors.lastname: Vanhoudt
authors.forename: Suzy
authors.initials: S
authors.lastname: Van Sanden
authors.forename: Frank
authors.initials: F
authors.lastname: Van Belleghem
authors.forename: Yves
authors.initials: Y
authors.lastname: Guisez
authors.forename: Jan
authors.initials: J
authors.lastname: Colpaert
authors.forename: Jaco
authors.initials: J
authors.lastname: Vangronsveld
mesh_terms: D017360:Arabidopsis / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D002104:Cadmium / Q000378:metabolism / Q000494:pharmacology*; D003300:Copper / Q000378:metabolism / Q000494:pharmacology*; D015870:Gene Expression / Q000187:drug effects; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics; D006861:Hydrogen Peroxide / Q000378:metabolism; D015227:Lipid Peroxidation; D008954:Models, Biological; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology*; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D015398:Signal Transduction; D013312:Stress, Physiological
chemical_list: D010940:Plant Proteins; D017382:Reactive Oxygen Species; D002104:Cadmium; D003300:Copper; D006861:Hydrogen Peroxide