title: Glutathione and transpiration as key factors conditioning oxidative stress in Arabidopsis thaliana exposed to uranium.
abstract: Although oxidative stress has been previously described in plants exposed to uranium (U), some uncertainty remains about the role of glutathione and tocopherol availability in the different responsiveness of plants to photo-oxidative damage. Moreover, in most cases, little consideration is given to the role of water transport in shoot heavy metal accumulation. Here, we investigated the effect of uranyl nitrate exposure (50 μM) on PSII and parameters involved in water transport (leaf transpiration and aquaporin gene expression) of Arabidopsis wild type (WT) and mutant plants that are deficient in tocopherol (vte1: null α/γ-tocopherol and vte4: null α-tocopherol) and glutathione biosynthesis (high content: cad1.3 and low content: cad2.1). We show how U exposure induced photosynthetic inhibition that entailed an electron sink/source imbalance that caused PSII photoinhibition in the mutants. The WT was the only line where U did not damage PSII. The increase in energy thermal dissipation observed in all the plants exposed to U did not avoid photo-oxidative damage of mutants. The maintenance of control of glutathione and malondialdehyde contents probed to be target points for the overcoming of photoinhibition in the WT. The relationship between leaf U content and leaf transpiration confirmed the relevance of water transport in heavy metals partitioning and accumulation in leaves, with the consequent implication of susceptibility to oxidative stress.
authors.affiliation: Instituto de Agrobiotecnología, Universidad Pública de Navarra-CSIC-Gobierno de Navarra, Campus de Arrosadía, 31192, Mutilva Baja, Spain, iker.aranjuelo@unavarra.es.
authors.forename: Iker
authors.initials: I
authors.lastname: Aranjuelo
authors.forename: Fany
authors.initials: F
authors.lastname: Doustaly
authors.forename: Jana
authors.initials: J
authors.lastname: Cela
authors.forename: Rosa
authors.initials: R
authors.lastname: Porcel
authors.forename: Maren
authors.initials: M
authors.lastname: Müller
authors.forename: Ricardo
authors.initials: R
authors.lastname: Aroca
authors.forename: Sergi
authors.initials: S
authors.lastname: Munné-Bosch
authors.forename: Jacques
authors.initials: J
authors.lastname: Bourguignon
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D017360:Arabidopsis / Q000187:drug effects* / Q000235:genetics / Q000502:physiology / Q000528:radiation effects; D001205:Ascorbic Acid / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D005978:Glutathione / Q000378:metabolism*; D008027:Light; D009154:Mutation; D018384:Oxidative Stress / Q000187:drug effects; D010788:Photosynthesis / Q000187:drug effects; D010860:Pigments, Biological; D010937:Plant Growth Regulators / Q000378:metabolism; D018515:Plant Leaves / Q000187:drug effects / Q000235:genetics / Q000502:physiology / Q000528:radiation effects; D018520:Plant Shoots / Q000187:drug effects / Q000235:genetics / Q000502:physiology / Q000528:radiation effects; D018526:Plant Transpiration / Q000187:drug effects; D013312:Stress, Physiological / Q000187:drug effects*; D024505:Tocopherols / Q000378:metabolism; D014501:Uranium / Q000494:pharmacology*
chemical_list: D000975:Antioxidants; D010860:Pigments, Biological; D010937:Plant Growth Regulators; D002734:Chlorophyll; D014501:Uranium; D005978:Glutathione; D001205:Ascorbic Acid; D024505:Tocopherols