title: Oxidative stress-related responses at transcriptional and enzymatic levels after exposure to Cd or Cu in a multipollution context.
abstract: The physiological effects of Cd and Cu have been highlighted in several studies over the last years. At the cellular level, oxidative stress has been reported as a common mechanism in both stress situations. Nevertheless, because of differences in their redox-related properties, the origin of the stress and regulation of these effects can be very different. Our results show a specific Cd-related induction of NADPH oxidases, whereas both metals induced lipid peroxidation via the activation of lipoxygenases. With respect to the antioxidative defense system, metal-specific patterns of superoxide dismutases (SODs) were detected, whereas gene expression levels of the H2O2-quenching enzymes were equally induced by both metals. Because monometallic exposure is very unusual in real-world situations, the metal-specific effects were compared with the mechanisms induced when the plants are exposed to both metals simultaneously. Combined exposure to Cd and Cu enhanced some of the effects that were induced when only one metal was applied to the medium. Other specific monometallically induced effects, such as a copper zinc superoxide dismutase (CSD2) downregulation due to Cd, were also sustained in a multipollution context, irrespective of the other monometallic effects. Furthermore, specific multipollution effects were unravelled, as iron superoxide dismutase 1 (FSD1) upregulation in the leaves was significant only when both Cu and Cd were applied. Additional relationships between these treatments and the common and specific stress induction mechanisms are discussed.
authors.affiliation: Hasselt University, Centre for Environmental Sciences, Agoralaan Building D, 3590 Diepenbeek, Belgium. karen.smeets@uhasselt.be
authors.forename: Karen
authors.initials: K
authors.lastname: Smeets
authors.forename: Kelly
authors.initials: K
authors.lastname: Opdenakker
authors.forename: Tony
authors.initials: T
authors.lastname: Remans
authors.forename: Suzy
authors.initials: S
authors.lastname: Van Sanden
authors.forename: Frank
authors.initials: F
authors.lastname: Van Belleghem
authors.forename: Brahim
authors.initials: B
authors.lastname: Semane
authors.forename: Nele
authors.initials: N
authors.lastname: Horemans
authors.forename: Yves
authors.initials: Y
authors.lastname: Guisez
authors.forename: Jaco
authors.initials: J
authors.lastname: Vangronsveld
authors.forename: Ann
authors.initials: A
authors.lastname: Cuypers
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000201:enzymology*; D001205:Ascorbic Acid / Q000378:metabolism; D002104:Cadmium / Q000633:toxicity*; D003300:Copper / Q000633:toxicity*; D004787:Environmental Pollution; D015870:Gene Expression / Q000187:drug effects; D005978:Glutathione / Q000378:metabolism; D015227:Lipid Peroxidation; D018384:Oxidative Stress
chemical_list: D002104:Cadmium; D003300:Copper; D005978:Glutathione; D001205:Ascorbic Acid