Characterization of loss-of-function mutants of AtGSTU7, AtGSTU8, AtGSTU18 and AtGSTU25 of Arabidopsis thaliana in response to abiotic stresses
Date Issued
2011
Date
2011
Author(s)
Chen, Yin-Chu
Abstract
Glutathione S-transferases (GSTs) have been well-documented to be involved in oxidative stress metabolism. However, reports on GST gene participating in regulatory function are limited. Previously our lab had found that glutathione S-transferase U17 (AtGSTU17) knock-out plants were more tolerant to drought and salt stresses than wild-type plants. The mechanism causing these phenotypes of atgstu17 can be explained mostly by the combined effect of elevated contents of both glutathione and abscisic acid. Thus, AtGSTU17 plays a negative role in regulating abiotic stress tolerance. Three homozygous knockout mutants, atgstu7, atgstu8, atgstu18, were chosen for further study with their function in response to abiotic stress. Preliminary stress experiments indicated that the mentioned above atgstu mutants showed different phenotypes from the atgstu17 mutant plants in terms of salt and drought tolerance. However, the germination rates of the three mutants were higher than wild-type plants when they were treated with abscisic acid, salt, and osmotic stress. We suggested that these three genes might play a negative regulatory role during seed imbibitions and seedling development under stress conditions. Genetic analysis of F2 segergating population indicated that wild-type (AtGSTU25/AtGSTU25), hemizygous (AtGSTU25/atgstu25), and homozygous mutant (atgstu25/atgstu25) plants were in a ratio of 1:2:0, indicating that the homozygous mutant allele is lethal.
Subjects
Glutathione S-transferases
glutathione
oxidative stress
drought tolerance
salt tolerance
Type
thesis
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