Plant Molecular Biology 37: 425–435, 1998.
1998 Kluwer Academic Publishers. Printed in Belgium.
Regulation of abscisic acid-induced transcription
Peter K. Busk
and Montserrat Pag
Departament de Gen
etica Molecular. Centre d’Investigaci
o i Desenvolupament. C.S.I.C. Jordi Girona 18-26,
08034 Barcelona, Spain;
Present adress: Plantebiokemisk Laboratorium. Den kongelige Veterinær- og
Landbohøjskole. Thorvaldsensvej 40. 1870 Frederiksberg C. Denmark (
author for correspondence)
Received 22 January 1998; accepted in revised form 27 January 1998
Key words: gene expression, protein-DNA interaction, plant, stress, seed development
The phytohormone abscisic acid is probably present in all higher plants. This hormone is necessary for regulation
of several events during seed development and for the response to environmental stresses such as desiccation, salt
and cold. An important part of the physiological response to abscisic acid is achieved through gene expression.
Here, we summarize the current knowledge of regulation of abscisic acid-induced transcription. The main
focus is on a description of the known abscisic acid-responsive cis-elements, their properties and the possible
transacting factors binding to the elements. Results have shown that cooperative action of cis-elements and the
promoter conﬁguraton is crucial for regulation by abscisic acid. Furthermore, several elements are organ- and
species-speciﬁc. Recent studies of the chromatin structure of abscisic acid-responsive genes point to the importance
of induction of transcription by coactivators or by phosphorylation/dephosphorylation of transcription factors. An
interesting example of activation by a cofactor is the cooperative action between abscisic acid-signaling and the
regulatory protein Viviparous 1 through the abscisic acid responsive element.
The phytohormone abscisic acid (ABA) plays an
important role in many physiological processes. This
hormone is necessary for regulation of several events
during late seed development (see review by [52, 57]).
Furthermore, ABA is crucial for the response to envir-
onmental stresses such as desiccation, salt and cold
(see review by [7, 43]). In this review we describe the
current knowledgeof regulation of ABA-induced tran-
scription. The genetics of ABA perception and gene
expression has been reviewed by McCarty  and
Leung and Giraudat . ABA signalling in guard
cells was reviewed recently [52, 107].
Biological roles of ABA
The concentration of ABA increases in late embryo
development shortly before the onset of desiccation
and seed dormancy [47, 94]. Genetic studies have
shown that ABA is involved in dormancy and matura-
tion, and ABA deﬁcient mutants have been isolated by
screening for precocious germination or reversion of
germination deﬁcient mutations (see review by ).
Transgenic tobacco expressing an ABA-antibody are
practically depleted of free ABA . Seeds of these
plants do not develop correctly which shows that ABA
is necessary for maturation. However, the wild type
level of ABA is far in excess of the concentration
required for maturation  and other factors must
be involved in controlling the developmental program.
Galau and coworkers showed that a few temporal pro-
grams that are unrelated to variations in ABA concen-
tration can explain the patterns of gene-expression in
cotton embryos [22, 36, 37]. These programs appear to
be controlled by maturation and postabscission factors
[23, 37]. The model seems to be valid also in Ara-
bidopsis [27, 72].