title: Increased sensitivity to salt stress in tocopherol-deficient Arabidopsis mutants growing in a hydroponic system.
abstract: Recent studies suggest that tocopherols could play physiological roles in salt tolerance but the mechanisms are still unknown. In this study, we analyzed changes in growth, mineral and oxidative status in vte1 and vte4 Arabidopsis thaliana mutants exposed to salt stress. vte1 and vte4 mutants lack α-tocopherol, but only the vte1 mutant is additionally deficient in γ-tocopherol. Results showed that a deficiency in vitamin E leads to reduced growth and increased oxidative stress in hydroponically-grown plants. This effect was observed at early stages, not only in rosettes but also in roots. The vte1 mutant was more sensitive to salt-induced oxidative stress than the wild type and the vte4 mutant. Salt sensitivity was associated with (i) high contents of Na(+), (ii) reduced efficiency of PSII photochemistry (Fv/Fm ratio) and (iii) more pronounced oxidative stress as indicated by increased hydrogen peroxide and malondialdeyde levels. The vte 4 mutant, which accumulates γ- instead of α-tocopherol showed an intermediate sensitivity to salt stress between the wild type and the vte1 mutant. Contents of abscisic acid, jasmonic acid and the ethylene precursor, 1-aminocyclopropane-1-carboxylic acid were higher in the vte1 mutant than the vte4 mutant and wild type. It is concluded that vitamin E-deficient plants show an increased sensitivity to salt stress both in rosettes and roots, therefore indicating the positive role of tocopherols in stress tolerance, not only by minimizing oxidative stress, but also controlling Na(+)/K(+) homeostasis and hormonal balance.
authors.affiliation: Departament de Biologia Vegetal; Facultat de Biologia; Universitat de Barcelona; Barcelona, Spain; Laboratoire des Plantes Extrêmophiles; Center of Biotechnology of Borj Cedria; Hammam, Tunisia.
authors.forename: Hasna
authors.initials: H
authors.lastname: Ellouzi
authors.affiliation: Laboratoire des Plantes Extrêmophiles; Center of Biotechnology of Borj Cedria; Hammam, Tunisia.
authors.forename: Karim Ben
authors.initials: KB
authors.lastname: Hamed
authors.affiliation: Departament de Biologia Vegetal; Facultat de Biologia; Universitat de Barcelona; Barcelona, Spain.
authors.forename: Jana
authors.initials: J
authors.lastname: Cela
authors.affiliation: Departament de Biologia Vegetal; Facultat de Biologia; Universitat de Barcelona; Barcelona, Spain.
authors.forename: Maren
authors.initials: M
authors.lastname: Müller
authors.affiliation: Laboratoire des Plantes Extrêmophiles; Center of Biotechnology of Borj Cedria; Hammam, Tunisia.
authors.forename: Chedly
authors.initials: C
authors.lastname: Abdelly
authors.affiliation: Departament de Biologia Vegetal; Facultat de Biologia; Universitat de Barcelona; Barcelona, Spain.
authors.forename: Sergi
authors.initials: S
authors.lastname: Munné-Bosch
mesh_terms: D000598:Amino Acids, Cyclic; D017360:Arabidopsis / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D003517:Cyclopentanes / Q000378:metabolism; D005030:Ethylenes / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D018527:Hydroponics; D018384:Oxidative Stress / Q000187:drug effects; D054883:Oxylipins / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology*; D024505:Tocopherols / Q000378:metabolism*
chemical_list: D000598:Amino Acids, Cyclic; D003517:Cyclopentanes; D005030:Ethylenes; D054883:Oxylipins; C023863:1-aminocyclopropane-1-carboxylic acid; D012965:Sodium Chloride; C011006:jasmonic acid; C036216:ethylene; D024505:Tocopherols
keywords: hormones; hydrogen peroxide; oxidative stress; salt stress; vitamin E