OPEN ACCESS ARTICLE

This Article Free via Open Access: OA OA Full Text Full Text (PDF) Supplemental Data OA All Versions of this Article: 146/2/623    most recent pp.107.110981v1 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 CrossRef Citing Articles via Google Scholar Google Scholar Articles by Jung, C. Articles by Cheong, J.-J. Search for Related Content PubMed PubMed Citation Articles by Jung, C. Articles by Cheong, J.-J. Agricola Articles by Jung, C. Articles by Cheong, J.-J. Related Collections Biology of Transpiration

ENVIRONMENTAL STRESS AND ADAPTATION TO STRESS

Overexpression of AtMYB44 Enhances Stomatal Closure to Confer Abiotic Stress Tolerance in Transgenic Arabidopsis^{1,[C],[W],[OA]}

Department of Agricultural Biotechnology and Center for Agricultural Biomaterials, Seoul National University, Seoul 151–921, Korea (C.J., J.S.S., S.W.H., Y.J.K., Y.D.C., J.-J.C.); Department of Food and Nutrition, Seowon University, Chongju 361–742, Korea (C.H.K.); and Division of Bioscience and Bioinformatics, Myongji University, Yongin 449–728, Korea (S.I.S., B.H.N.)

AtMYB44 belongs to the R2R3 MYB subgroup 22 transcription factor family in Arabidopsis (Arabidopsis thaliana). Treatment with abscisic acid (ABA) induced AtMYB44 transcript accumulation within 30 min. The gene was also activated under various abiotic stresses, such as dehydration, low temperature, and salinity. In transgenic Arabidopsis carrying an AtMYB44 promoter-driven β-glucuronidase (GUS) construct, strong GUS activity was observed in the vasculature and leaf epidermal guard cells. Transgenic Arabidopsis overexpressing AtMYB44 is more sensitive to ABA and has a more rapid ABA-induced stomatal closure response than wild-type and atmyb44 knockout plants. Transgenic plants exhibited a reduced rate of water loss, as measured by the fresh-weight loss of detached shoots, and remarkably enhanced tolerance to drought and salt stress compared to wild-type plants. Microarray analysis and northern blots revealed that salt-induced activation of the genes that encode a group of serine/threonine protein phosphatases 2C (PP2Cs), such as ABI1, ABI2, AtPP2CA, HAB1, and HAB2, was diminished in transgenic plants overexpressing AtMYB44. By contrast, the atmyb44 knockout mutant line exhibited enhanced salt-induced expression of PP2C-encoding genes and reduced drought/salt stress tolerance compared to wild-type plants. Therefore, enhanced abiotic stress tolerance of transgenic Arabidopsis overexpressing AtMYB44 was conferred by reduced expression of genes encoding PP2Cs, which have been described as negative regulators of ABA signaling.

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: Jong-Joo Cheong (cheongjj{at}snu.ac.kr).

^[C] Some figures in this article are displayed in color online but in black and white in the print edition.

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

^[OA] Open Access articles can be viewed online without a subscription.

www.plantphysiol.org/cgi/doi/10.1104/pp.107.110981

^* Corresponding author; e-mail cheongjj{at}snu.ac.kr.

Received October 15, 2007; accepted December 16, 2007; published December 27, 2007.