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An Arabidopsis mutant with deregulated ABA gene expression: implications for negative regulator function
Author(s) -
Foster Randy,
Chua NamHai
Publication year - 1999
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.1999.00384.x
Subject(s) - arabidopsis , mutant , abscisic acid , biology , transgene , luciferase , gene , gene expression , arabidopsis thaliana , microbiology and biotechnology , regulator , regulation of gene expression , genetics , transfection
Summary The physiological acclimation of plants to osmotic stresses involves a complex programme of gene regulation. In one signalling pathway, elevated levels of abscisic acid (ABA) activate a subset of stress genes. Because ABA responses lack a definable morphological phenotype, we have screened for mutants that exhibit deregulated ABA‐responsive gene expression. To monitor this ABA response, a line ofArabidopsis thalianacarrying a transgene composed of the ABA‐responsiveArabidopsis kin2promoter fused to the coding sequence for the firefly luciferase gene,kin2::luc, was generated. Patterns of ABA‐responsive luciferase activity were monitored by photon counting. In contrast to wild‐type plants which display a transient activation ofkin2::luc, an ABA deregulated gene expression mutant (ade1) exhibits both sustained and enhanced levels of transgene activity. Levels ofkin2,cor47andrab18expression inade1plants are also enhanced and prolonged indicating that the molecular mechanism(s) altered inade1plants affects the regulation of other ABA‐responsive genes. The mutant phenotype is specific for the ABA response as cold‐induciblekin2expression is unaltered inade1plants. Genetic analyses indicate that theade1mutant is a monogenic recessive trait. A role for negative regulator function in ABA signalling is discussed.