title: Induction of Oxidative Stress and Antioxidative Mechanisms in Arabidopsis thaliana after Uranium Exposure at pH 7.5.
abstract: To evaluate the environmental impact of uranium (U) contamination, it is important to investigate the effects of U at ecologically relevant conditions. Since U speciation, and hence its toxicity, strongly depends on environmental pH, the present study aimed to investigate dose-dependent effects of U at pH 7.5. Arabidopsis thaliana plants (Mouse-ear Cress) were exposed for three days to different U concentrations at pH 7.5. In the roots, the increased capacities of ascorbate peroxidase and glutathione reductase indicate an important role for the ascorbate-glutathione cycle during U-induced stress. However, a significant decrease in the ascorbate redox state was observed after exposure to 75 and 100 µM U, indicating that those roots are severely stressed. In accordance with the roots, the ascorbate-glutathione cycle plays an important role in the antioxidative defence systems in A. thaliana leaves exposed to U at pH 7.5 as the ascorbate and glutathione biosynthesis were upregulated. In addition, small inductions of enzymes of the antioxidative defence system were observed at lower U concentrations to counteract the U-induced stress. However, at higher U concentrations it seems that the antioxidative defence system of the leaves collapses as reductions in enzyme activities and gene expression levels were observed.
authors.affiliation: Belgian Nuclear Research Centre (SCK•CEN), Biosphere Impact Studies, Boeretang 200, 2400 Mol, Belgium. eline.saenen@sckcen.be.|Hasselt University, Centre for Environmental Sciences, Agoralaan Building D, 3590 Diepenbeek, Belgium. eline.saenen@sckcen.be.
authors.forename: Eline
authors.initials: E
authors.lastname: Saenen
authors.affiliation: Belgian Nuclear Research Centre (SCK•CEN), Biosphere Impact Studies, Boeretang 200, 2400 Mol, Belgium. nele.horemans@sckcen.be.
authors.forename: Nele
authors.initials: N
authors.lastname: Horemans
authors.affiliation: Belgian Nuclear Research Centre (SCK•CEN), Biosphere Impact Studies, Boeretang 200, 2400 Mol, Belgium. nathalie.vanhoudt@sckcen.be.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Vanhoudt
authors.affiliation: Belgian Nuclear Research Centre (SCK•CEN), Biosphere Impact Studies, Boeretang 200, 2400 Mol, Belgium. hildegarde.vandenhove@sckcen.be.
authors.forename: Hildegarde
authors.initials: H
authors.lastname: Vandenhove
authors.affiliation: Belgian Nuclear Research Centre (SCK•CEN), Biosphere Impact Studies, Boeretang 200, 2400 Mol, Belgium. geert.biermans@gmail.com.|Hasselt University, Centre for Environmental Sciences, Agoralaan Building D, 3590 Diepenbeek, Belgium. geert.biermans@gmail.com.
authors.forename: Geert
authors.initials: G
authors.lastname: Biermans
authors.affiliation: Belgian Nuclear Research Centre (SCK•CEN), Biosphere Impact Studies, Boeretang 200, 2400 Mol, Belgium. mvhees@sckcen.be.
authors.forename: May
authors.initials: M
authors.lastname: Van Hees
authors.affiliation: Belgian Nuclear Research Centre (SCK•CEN), Biosphere Impact Studies, Boeretang 200, 2400 Mol, Belgium. jwannijg@sckcen.be.
authors.forename: Jean
authors.initials: J
authors.lastname: Wannijn
authors.affiliation: Hasselt University, Centre for Environmental Sciences, Agoralaan Building D, 3590 Diepenbeek, Belgium. jaco.vangronsveld@uhasselt.be.
authors.forename: Jaco
authors.initials: J
authors.lastname: Vangronsveld
authors.affiliation: Hasselt University, Centre for Environmental Sciences, Agoralaan Building D, 3590 Diepenbeek, Belgium. ann.cuypers@uhasselt.be.
authors.forename: Ann
authors.initials: A
authors.lastname: Cuypers
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D017360:Arabidopsis / Q000187:drug effects* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000378:metabolism; D001205:Ascorbic Acid / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005978:Glutathione / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D018384:Oxidative Stress; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism; D014501:Uranium / Q000494:pharmacology*
chemical_list: D000975:Antioxidants; D029681:Arabidopsis Proteins; D014501:Uranium; D005978:Glutathione; D001205:Ascorbic Acid
keywords: Arabidopsis thaliana; ascorbate-glutathione cycle; gene expression; oxidative stress; uranium toxicity