Author:
Audran Corinne,Liotenberg Sylviane,Gonneau Martine,North Helen,Frey Anne,Tap-Waksman Karine,Vartanian Nicole,Marion-Poll Annie
Abstract
Abscisic acid (ABA) is involved in seed development and plant adaptation to
environmental stresses. ABA is synthesized from cleaved xanthophylls and
zeaxanthin epoxidase (ZEP) is the enzyme responsible for the conversion of
zeaxanthin to violaxanthin. In this study, we have characterized the
ABA1 gene (AtZEP) of
Arabidopsis thaliana L. and show that this complements
the aba1 mutant, defective in zeaxanthin epoxidation.
The molecular basis for two aba1 mutant alleles has been
determined and the reduction in their AtZEP transcript
levels correlates with the molecular defect identified. As
AtZEP mRNA abundance was not affected in two other
ABA-deficient mutants (aba2 and
aba3) and in two ABA-insensitive mutants
(abi1 and abi2), no feedback
regulation of ABA biosynthesis seems to occur at the level of
ZEP transcription. Steady state transcript levels
increased in roots during rapid water stress as well as progressive drought
stress, providing evidence that zeaxanthin epoxidation contributed to the
regulation of ABA biosynthesis in roots and consequently to the plant adaptive
response to hydric stress. In seeds in situ
hybridization analysis detectedAtZEP mRNA in the embryo
cells from the globular stage to desiccation phase. In contrast, expression of
AtZEP in maternal tissues was specific to the maturation
phase. These results are discussed in relation to the role of ABA both in
response to drought stress and in seed development.
Subject
Plant Science,Agronomy and Crop Science
Cited by
30 articles.
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