Enhanced oxidative stress in the ethylene-insensitive (ein3-1) mutant of Arabidopsis thaliana exposed to salt stress.
To better understand the role of ethylene signaling in plant stress tolerance, salt-induced changes in gene expression levels of ethylene biosynthesis, perception and signaling genes were measured in Arabidopsis thaliana plants exposed to 15 days of salinity. Among the genes analyzed, EIN3 showed the highest expression level increase under salt stress, suggesting a key role for this ethylene-signaling component in response to salt stress. Therefore, we analyzed the salt stress response over 15 days (by adding 100 mM NaCl to the nutrient solution) in the ein3-1 mutant compared to the wild-type (Col-0) in terms of growth, oxidative stress markers (lipid peroxidation, foliar pigments and low-molecular-weight antioxidants) and levels of growth- and stress-related phytohormones (including cytokinins, auxins, gibberellins, abscisic acid, jasmonic acid and salicylic acid). The ein3-1 mutant grew similarly to wild-type plants both under control and salt stress conditions, which was associated with a differential time course evolution in the levels of the cytokinins zeatin and zeatin riboside, and the auxin indole-3-acetic acid between the ein3-1 mutant and the wild-type. Despite showing no signs of physiological deterioration under salt stress (in terms of rosette biomass, leaf water and pigment contents, and PSII efficiency) the ein3-1 mutant showed enhanced lipid peroxidation under salt stress, as indicated by 2.4-fold increase in both malondialdehyde and jasmonic acid contents compared to the wild-type. We conclude that, at moderate doses of salinity, partial insensitivity to ethylene might be compensated by changes in endogenous levels of other phytohormones and lipid peroxidation-derived signals in the ein3-1 mutant exposed to salt stress, but at the same time, this mutant shows higher oxidative stress under salinity than the wild-type.
Departament de Biologia Vegetal, Universitat de Barcelona, Avinguda Diagonal 645, 08028 Barcelona, Spain.
María Amparo
MA
Asensi-Fabado
Jana
J
Cela
Maren
M
Müller
Laia
L
Arrom
Caren
C
Chang
Sergi
S
Munné-Bosch
D000975:Antioxidants / Q000378:metabolism; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D018533:Biomass; D002734:Chlorophyll / Q000378:metabolism; D003517:Cyclopentanes / Q000378:metabolism; D004268:DNA-Binding Proteins; D005030:Ethylenes / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D007210:Indoleacetic Acids / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects / Q000502:physiology; D008315:Malondialdehyde / Q000378:metabolism; D009154:Mutation; D009687:Nuclear Proteins / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects*; D054883:Oxylipins / Q000378:metabolism; D010937:Plant Growth Regulators / Q000378:metabolism*; D018515:Plant Leaves / Q000235:genetics; D036226:Seedlings / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D015398:Signal Transduction / Q000187:drug effects; D012965:Sodium Chloride / Q000633:toxicity*; D014157:Transcription Factors / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D014867:Water / Q000378:metabolism
D000975:Antioxidants; D029681:Arabidopsis Proteins; D003517:Cyclopentanes; D004268:DNA-Binding Proteins; C106987:EIN3 protein, Arabidopsis; D005030:Ethylenes; D007210:Indoleacetic Acids; D009687:Nuclear Proteins; D054883:Oxylipins; D010937:Plant Growth Regulators; D014157:Transcription Factors; D014867:Water; D002734:Chlorophyll; D012965:Sodium Chloride; D008315:Malondialdehyde; C011006:jasmonic acid; C030737:indoleacetic acid; C036216:ethylene