Plant Cell Advance Online Publication
Published on October 21, 2008; 10.1105/tpc.108.061515
Received June 17, 2008
Returned for revision September 19, 2008
Accepted October 6, 2008
The Gibberellic Acid Signaling Repressor RGL2 Inhibits Arabidopsis Seed Germination by Stimulating Abscisic Acid Synthesis and ABI5 Activity
Urszula Piskurewicz 1, Yusuke Jikumaru 2, Natsuko Kinoshita 1, Eiji Nambara 2, Yuji Kamiya 2, and Luis Lopez-Molina 1*
1 Université de Genève, Département de Biologie Végétale, 1211 Geneva 4, Switzerland
2 Plant Science Center, RIKEN, Tsurumi-ku, Yokohama 230-0045, Japan
* To whom correspondence should be addressed. E-mail: luis.lopezmolina{at}unige.ch.
Seed germination is antagonistically controlled by the phytohormones gibberellic acid (GA) and abscisic acid (ABA). GA promotes seed germination by enhancing the proteasome-mediated destruction of RGL2 (for RGA-LIKE2), a key DELLA factor repressing germination. By contrast, ABA blocks germination by inducing ABI5 (for ABA-INSENSITIVE5), a basic domain/leucine zipper transcription factor repressing germination. We show that decreased GA synthesis leads to an increase in XERICO expression, a RING-H2 zinc finger factor promoting an increase of endogenous ABA levels in a RGL2-dependent manner. In turn, increased endogenous ABA synthesis is necessary to elevate not only ABI5 RNA and protein levels but also, critically, those of RGL2. Increased ABI5 protein is ultimately responsible for preventing seed germination when GA levels are reduced. However, overexpression of ABI5 was not sufficient to repress germination, as ABI5 activity requires phosphorylation. The endogenous ABI5 phosphorylation and inhibition of germination could be recapitulated by the addition of a SnRK2 protein kinase to the ABI5 overexpression line. In sleepy1 mutant seeds, RGL2 overaccumulates; germination of these seeds can occur under conditions that produce low ABI5 expression. These data support the notion that ABI5 acts as the final common repressor of germination in response to changes in ABA and GA levels.
This article has been cited by other articles:
|
|
|
|
 
N. Kinoshita, A. Berr, C. Belin, R. Chappuis, N. K. Nishizawa, and L. Lopez-Molina
Identification of growth insensitive to ABA3 (gia3), a Recessive Mutation Affecting ABA Signaling for the Control of Early Post-Germination Growth in Arabidopsis thaliana
Plant Cell Physiol.,
February 1, 2010;
51(2):
239 - 251.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
A. Linkies, K. Muller, K. Morris, V. Tureckova, M. Wenk, C. S.C. Cadman, F. Corbineau, M. Strnad, J. R. Lynn, W. E. Finch-Savage, et al.
Ethylene Interacts with Abscisic Acid to Regulate Endosperm Rupture during Germination: A Comparative Approach Using Lepidium sativum and Arabidopsis thaliana
PLANT CELL,
December 1, 2009;
21(12):
3803 - 3822.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
S. Penfield and J. King
Towards a systems biology approach to understanding seed dormancy and germination
Proc R Soc B,
October 22, 2009;
276(1673):
3561 - 3569.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
M. V. Rodriguez, G. M. Mendiondo, L. Maskin, G. E. Gudesblat, N. D. Iusem, and R. L. Benech-Arnold
Expression of ABA signalling genes and ABI5 protein levels in imbibed Sorghum bicolor caryopses with contrasting dormancy and at different developmental stages
Ann. Bot.,
October 1, 2009;
104(5):
975 - 985.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
C. Belin, C. Megies, E. Hauserova, and L. Lopez-Molina
Abscisic Acid Represses Growth of the Arabidopsis Embryonic Axis after Germination by Enhancing Auxin Signaling
PLANT CELL,
August 1, 2009;
21(8):
2253 - 2268.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
K. Nakashima, Y. Fujita, N. Kanamori, T. Katagiri, T. Umezawa, S. Kidokoro, K. Maruyama, T. Yoshida, K. Ishiyama, M. Kobayashi, et al.
Three Arabidopsis SnRK2 Protein Kinases, SRK2D/SnRK2.2, SRK2E/SnRK2.6/OST1 and SRK2I/SnRK2.3, Involved in ABA Signaling are Essential for the Control of Seed Development and Dormancy
Plant Cell Physiol.,
July 1, 2009;
50(7):
1345 - 1363.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
H. Fujii and J.-K. Zhu
Arabidopsis mutant deficient in 3 abscisic acid-activated protein kinases reveals critical roles in growth, reproduction, and stress
PNAS,
May 19, 2009;
106(20):
8380 - 8385.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
K. Miura, J. Lee, J. B. Jin, C. Y. Yoo, T. Miura, and P. M. Hasegawa
Sumoylation of ABI5 by the Arabidopsis SUMO E3 ligase SIZ1 negatively regulates abscisic acid signaling
PNAS,
March 31, 2009;
106(13):
5418 - 5423.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
