Plant Physiology Preview
Published on December 16, 2005; 10.1104/pp.105.070318
Received August 24, 2005
Returned for revision October 13, 2005
Accepted October 23, 2005
The Protein Phosphatase AtPP2CA Negatively Regulates Abscisic Acid Signal Transduction in Arabidopsis
Josef M. Kuhn , Aurélien Boisson-Dernier , Marie B. Dizon , Mohammad H. Maktabi , and Julian I. Schroeder *
Division of Biological Sciences, Cell and Developmental Biology Section, and Center for Molecular Genetics, University of California, La Jolla, California 92093-0116
* Corresponding author; email: julian{at}biomail.ucsd.edu.
To identify new loci in abscisic acid (ABA) signaling, we screened a library of 35S::cDNA Arabidopsis (Arabidopsis thaliana)-expressing lines for ABA-insensitive mutants in seed germination assays. One of the identified mutants germinated on 2.5 µM ABA, a concentration that completely inhibits wild-type seed germination. Backcrosses and F2 analyses indicated that the mutant exhibits a dominant phenotype and that the ABA insensitivity was linked to a single T-DNA insertion containing a 35S::cDNA fusion. The inserted cDNA corresponds to a full-length cDNA of the AtPP2CA gene, encoding a protein phosphatase type 2C (PP2C). Northern-blot analyses demonstrated that the AtPP2CA transcript is indeed overexpressed in the mutant (named PP2CAox). Two independent homozygous T-DNA insertion lines, pp2ca-1 and pp2ca-2, were recovered from the Arabidopsis Biological Resource Center and shown to lack full-length AtPP2CA expression. A detailed characterization of PP2CAox and the T-DNA disruption mutants demonstrated that, whereas ectopic expression of a 35S::AtPP2CA fusion caused ABA insensitivity in seed germination and ABA-induced stomatal closure responses, disruption mutants displayed the opposite phenotype, namely, strong ABA hypersensitivity. Thus our data demonstrate that the PP2CA protein phosphatase is a strong negative regulator of ABA signal transduction. Furthermore, it has been previously shown that the AtPP2CA transcript is down-regulated in the ABA-hypersensitive nuclear mRNA cap-binding protein mutant abh1. We show here that down-regulation of AtPP2CA in abh1 is not due to impaired RNA splicing of AtPP2CA pre-mRNA. Moreover, expression of a 35S::AtPP2CA cDNA fusion in abh1 partially suppresses abh1 hypersensitivity, and the data further suggest that additional mechanisms contribute to ABA hypersensitivity of abh1.
This article has been cited by other articles:
|
|
|
|
 
C. Papdi, E. Abraham, M. P. Joseph, C. Popescu, C. Koncz, and L. Szabados
Functional Identification of Arabidopsis Stress Regulatory Genes Using the Controlled cDNA Overexpression System
Plant Physiology,
June 1, 2008;
147(2):
528 - 542.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
C. Jung, J. S. Seo, S. W. Han, Y. J. Koo, C. H. Kim, S. I. Song, B. H. Nahm, Y. D. Choi, and J.-J. Cheong
Overexpression of AtMYB44 Enhances Stomatal Closure to Confer Abiotic Stress Tolerance in Transgenic Arabidopsis
Plant Physiology,
February 1, 2008;
146(2):
623 - 635.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
A. Rosado, A. L. Schapire, R. A. Bressan, A. L. Harfouche, P. M. Hasegawa, V. Valpuesta, and M. A. Botella
The Arabidopsis Tetratricopeptide Repeat-Containing Protein TTL1 Is Required for Osmotic Stress Responses and Abscisic Acid Sensitivity
Plant Physiology,
November 1, 2006;
142(3):
1113 - 1126.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
Y. Miao, D. Lv, P. Wang, X.-C. Wang, J. Chen, C. Miao, and C.-P. Song
An Arabidopsis Glutathione Peroxidase Functions as Both a Redox Transducer and a Scavenger in Abscisic Acid and Drought Stress Responses
PLANT CELL,
October 1, 2006;
18(10):
2749 - 2766.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
A. Saez, N. Robert, M. H. Maktabi, J. I. Schroeder, R. Serrano, and P. L. Rodriguez
Enhancement of Abscisic Acid Sensitivity and Reduction of Water Consumption in Arabidopsis by Combined Inactivation of the Protein Phosphatases Type 2C ABI1 and HAB1
Plant Physiology,
August 1, 2006;
141(4):
1389 - 1399.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
D. Reyes, D. Rodriguez, M. P. Gonzalez-Garcia, O. Lorenzo, G. Nicolas, J. L. Garcia-Martinez, and C. Nicolas
Overexpression of a Protein Phosphatase 2C from Beech Seeds in Arabidopsis Shows Phenotypes Related to Abscisic Acid Responses and Gibberellin Biosynthesis
Plant Physiology,
August 1, 2006;
141(4):
1414 - 1424.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
J. M. Kwak, V. Nguyen, and J. I. Schroeder
The Role of Reactive Oxygen Species in Hormonal Responses
Plant Physiology,
June 1, 2006;
141(2):
323 - 329.
[Full Text]
[PDF]
|
|
|
|
|
|
|
T. Yoshida, N. Nishimura, N. Kitahata, T. Kuromori, T. Ito, T. Asami, K. Shinozaki, and T. Hirayama
ABA-Hypersensitive Germination3 Encodes a Protein Phosphatase 2C (AtPP2CA) That Strongly Regulates Abscisic Acid Signaling during Germination among Arabidopsis Protein Phosphatase 2Cs
Plant Physiology,
January 1, 2006;
140(1):
115 - 126.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
