Transcriptional regulation of ABI3- and ABA-responsive genes
including RD29B and RD29A in seeds, germinating embryos,
and seedlings of Arabidopsis
Kazuo Nakashima
1
, Yasunari Fujita
1
, Koji Katsura
1
, Kyonoshin Maruyama
1
, Yoshihiro
Narusaka
1,
, Motoaki Seki
2,3
, Kazuo Shinozaki
2,3,4
and Kazuko Yamaguchi-
Shinozaki
1,4,5,
*
1
Biological Resources Division, Japan International Research Center for Agricultural Sciences (JIRCAS),
1-1 Ohwashi, Tsukuba 305-8686, Japan;
2
Laboratory of Plant Molecular Biology, RIKEN Tsukuba Institute,
3-1-1 Koyadai, Tsukuba 305-0074, Japan;
3
Plant Functional Genomics Group, RIKEN Genomic Science
Center, Yokohama 230-0045, Japan;
4
Core Research for Evolutional Science and Technology (CREST),
Japan Science and Technology Agency, Kawaguchi 332-0012, Japan;
5
Laboratory of Plant Molecular
Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1 Yayoi, Bunkyo-
ku, Tokyo 113-8657, Japan (*author for correspondence; e-mail kazukoys@jircas.affrc.go.jp);
Present
address: Department of Biology, Tokyo Gakugei University, 4-1-1 Nukuikita-machi, Koganei-shi, Tokyo 184-
8501, Japan
Received 26 May 2005; accepted in revised form 23 August 2005
Key words: Arabidopsis, ABA, ABI3, ABRE, DRE, germinating embryo
Abstract
ABA-responsive elements (ABREs) are cis-acting elements and basic leucine zipper (bZIP)-type ABRE-
binding proteins (AREBs) are transcriptional activators that function in the expression of RD29B in
vegetative tissue of Arabidopsis in response to abscisic acid (ABA) treatment. Dehydration-responsive
elements (DREs) function as coupling elements of ABRE in the expression of RD29A in response to ABA.
Expression analysis using abi3 and abi5 mutants showed that ABI3 and ABI5 play important roles in the
expression of RD29B in seeds. Base-substitution analysis showed that two ABREs function strongly and
one ABRE coupled with DRE functions weakly in the expression of RD29A in embryos. In a transient
transactivation experiment, ABI3, ABI5 and AREB1 activated transcription of a GUS reporter gene driven
by the RD29B promoter strongly but these proteins activated the transcription driven by the RD29A
promoter weakly. In 35S::ABI3 Arabidopsis plants, the expression of RD29B was up-regulated strongly, but
that of RD29A was up-regulated weakly. These results indicate that the expression of RD29B having
ABREs in the promoter is up-regulated strongly by ABI3, whereas that of RD29A having one ABRE
coupled with DREs in the promoter is up-regulated weakly by ABI3. We compared the expression of 7000
Arabidopsis genes in response to ABA treatment during germination and in the vegetative growth stage,
and that in 35S::ABI3 plants using a full-length cDNA microarray. The expression of ABI3- and/or ABA-
responsive genes and cis-elements in the promoters are discussed.
Introduction
The phytohormone abscisic acid (ABA) plays
important roles in the adaptation of vegetative
tissue to abiotic environmental stresses such as
drought and high salinity as well as in seed
maturation and dormancy. ABA promotes stoma-
tal closure in guard cells by controlling solute
Plant Molecular Biology (2006) 60:51–68 Ó Springer 2006
DOI 10.1007/s11103-005-2418-5