TITLE:
Water-Deficit Response Is Not Affected by Glutathione Deficiency in Arabidopsis thaliana pad2-1 Plants
AUTHORS:
Tana Jubany-Marí, Seán Meehan, Marta López-Carbonell, Leonor Alegre
KEYWORDS:
Abscisic Acid, Antioxidants, Growth, Hydrogen Peroxide, pad2-1, Water Stress
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.7 No.14,
October
19,
2016
ABSTRACT: Changes in glutathione and ascorbate content,
hydrogen peroxide and abscisic acid were studied in developing leaves in
wild-type (Col-0) and glutathione-deficient mutant pad2-1 lines of Arabidopsis thaliana over a time period
of 9 days of drought followed by re-watering. Glutathione deficient mutant (pad2-1) presents mechanisms of
acclimation to water stress through the reduction of plant biomass and increase
in endogenous concentrations of ascorbate and glutathione. These acclimation
responses to stress appeared along with the first symptoms of stress and we
suggest here that they are regulated by ABA and H2O2.
Normally, wild type plants under conditions of stress require an initial
response phase in which a decrease in antioxidants is observed before reaching
acclimation through the increase in levels of antioxidants. pad2-1 is more sensitive to stress and reacts to it; however, it did not
suffer more oxidative stress than Col-0 plants, even though pad2-1 had higher levels of endogenous H2O2 relative to wild-type. In both water stressed Col-0 and pad2-1 plants increases
in ABA were observed, however, more sharply in wild-type stressed plants. Low levels of glutathione
together with high levels of H2O2 may regulate endogenous
ABA concentrations and could be related to the slow growth rates which were
observed during the experiment. The results highlighted the double function of
glutathione as an antioxidant and signal molecule and also, the different
response patterns of wild-type and pad2-1
when faced with drought stress. The results bring new insights to the responses
of pad2-1 under conditions of water stress.