This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: 141/4/1389    most recent pp.106.081018v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via ISI Web of Science (9) Citing Articles via Google Scholar Google Scholar Articles by Saez, A. Articles by Rodriguez, P. L. Search for Related Content PubMed PubMed Citation Articles by Saez, A. Articles by Rodriguez, P. L. Agricola Articles by Saez, A. Articles by Rodriguez, P. L. Related Collections Biology of Transpiration

DEVELOPMENT AND HORMONE ACTION

Enhancement of Abscisic Acid Sensitivity and Reduction of Water Consumption in Arabidopsis by Combined Inactivation of the Protein Phosphatases Type 2C ABI1 and HAB1^1,[W]

Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científicas, E–46022 Valencia, Spain (A.S., R.S., P.L.R.); and Cell and Developmental Biology Section, Division of Biological Sciences and Center for Molecular Genetics, University of California, San Diego, La Jolla, California 92093–0116 (N.R., M.H.M., J.I.S.)

Abscisic acid (ABA) plays a key role in plant responses to abiotic stress, particularly drought stress. A wide number of ABA-hypersensitive mutants is known, however, only a few of them resist/avoid drought stress. In this work we have generated ABA-hypersensitive drought-avoidant mutants by simultaneous inactivation of two negative regulators of ABA signaling, i.e. the protein phosphatases type 2C (PP2Cs) ABA-INSENSITIVE1 (ABI1) and HYPERSENSITIVE TO ABA1 (HAB1). Two new recessive loss-of-function alleles of ABI1, abi1-2 and abi1-3, were identified in an Arabidopsis (Arabidopsis thaliana) T-DNA collection. These mutants showed enhanced responses to ABA both in seed and vegetative tissues, but only a limited effect on plant drought avoidance. In contrast, generation of double hab1-1 abi1-2 and hab1-1 abi1-3 mutants strongly increased plant responsiveness to ABA. Thus, both hab1-1 abi1-2 and hab1-1 abi1-3 were particularly sensitive to ABA-mediated inhibition of seed germination. Additionally, vegetative responses to ABA were reinforced in the double mutants, which showed a strong hypersensitivity to ABA in growth assays, stomatal closure, and induction of ABA-responsive genes. Transpirational water loss under drought conditions was noticeably reduced in the double mutants as compared to single parental mutants, which resulted in reduced water consumption of whole plants. Taken together, these results reveal cooperative negative regulation of ABA signaling by ABI1 and HAB1 and suggest that fine tuning of ABA signaling can be attained through combined action of PP2Cs. Finally, these results suggest that combined inactivation of specific PP2Cs involved in ABA signaling could provide an approach for improving crop performance under drought stress conditions.

The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (www.plantphysiol.org) is: Pedro L. Rodriguez (prodriguez{at}ibmcp.upv.es).

^[W] The online version of this article contains Web-only data.

Article, publication date, and citation information can be found at www.plantphysiol.org/cgi/doi/10.1104/pp.106.081018.

^* Corresponding author; e-mail prodriguez{at}ibmcp.upv.es; fax 34963877859.

Received March 29, 2006; returned for revision June 8, 2006; accepted June 8, 2006.

This article has been cited by other articles:

				A. Wasilewska, F. Vlad, C. Sirichandra, Y. Redko, F. Jammes, C. Valon, N. F. d. Frey, and J. Leung An Update on Abscisic Acid Signaling in Plants and More ... Mol Plant, March 1, 2008; 1(2): 198 - 217. [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]

				S. E. Nilson and S. M. Assmann The Control of Transpiration. Insights from Arabidopsis Plant Physiology, January 1, 2007; 143(1): 19 - 27. [Full Text] [PDF]