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First published online August 13, 2008; 10.1104/pp.108.122945 Plant Physiology 148:1094-1105 (2008) © 2008 American Society of Plant Biologists Putrescine Is Involved in Arabidopsis Freezing Tolerance and Cold Acclimation by Regulating Abscisic Acid Levels in Response to Low Temperature1Unitat de Fisiologia Vegetal, Facultat de Farmàcia, Universitat de Barcelona, 08028 Barcelona, Spain (J.C.C., T.A., A.F.T.); Departamento de Biotecnología, Instituto Nacional de Investigación y Tecnología Agraría y Alimentaria, 28040 Madrid, Spain (R.L.-C., J.S.); Max-Planck Institut für Züchtungsforschung, D–50829 Cologne, Germany (R.A., C.K.); Departamento de Biología de Plantas, Centro de Investigaciones Biológicas, 28040 Madrid, Spain (J.S.); and Departament de Bioquímica i Biologia Molecular, Universitat de València, Burjassot, 46100 València, Spain (A.F.)
The levels of endogenous polyamines have been shown to increase in plant cells challenged with low temperature; however, the functions of polyamines in the regulation of cold stress responses are unknown. Here, we show that the accumulation of putrescine under cold stress is essential for proper cold acclimation and survival at freezing temperatures because Arabidopsis (Arabidopsis thaliana) mutants defective in putrescine biosynthesis (adc1, adc2) display reduced freezing tolerance compared to wild-type plants. Genes ADC1 and ADC2 show different transcriptional profiles upon cold treatment; however, they show similar and redundant contributions to cold responses in terms of putrescine accumulation kinetics and freezing sensitivity. Our data also demonstrate that detrimental consequences of putrescine depletion during cold stress are due, at least in part, to alterations in the levels of abscisic acid (ABA). Reduced expression of NCED3, a key gene involved in ABA biosynthesis, and down-regulation of ABA-regulated genes are detected in both adc1 and adc2 mutant plants under cold stress. Complementation analysis of adc mutants with ABA and reciprocal complementation tests of the aba2-3 mutant with putrescine support the conclusion that putrescine controls the levels of ABA in response to low temperature by modulating ABA biosynthesis and gene expression.
1 This work was supported by the Ramón y Cajal Program of the Spanish Ministry of Science and Education to A.F. and by projects BIO2002–11200–E and BIO2005–09252–C02–01 to A.F.T., EU–QLK5–CT–2002–00841 to A.F.T. and C.K., 2005SGR00020 (Generalitat de Catalunya) to T.A., and BIO2007–65248 and GEN2006–27787–E to J.S. C.K. and A.F.T. acknowledge support from Deutscher Akademischer Austausch Dienst and Ministerio de Educación y Ciencia-"Acciones Integradas" (HA2001–0001). J.C.C. is a FPI fellow of the Spanish Ministry of Science and Education. 2 Present address: Consorci CSIC-IRTA, Laboratori de Genètica Molecular Vegetal, IBMB-CSIC, Jordi Girona 18–26, 08034 Barcelona, Spain. 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: Alejandro Ferrando (alejandro.ferrando{at}uv.es). www.plantphysiol.org/cgi/doi/10.1104/pp.108.122945 * Corresponding author; e-mail alejandro.ferrando{at}uv.es. Received May 14, 2008; accepted July 25, 2008; published August 13, 2008. This article has been cited by other articles:
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