Article
- The EMBO Journal (2008) 27, 1277 - 1288
- doi:10.1038/emboj.2008.68
Published online: 3 April 2008
Subject Categories:
Arabidopsis COP1 shapes the temporal pattern of CO accumulation conferring a photoperiodic flowering responseEMBO Open
Seonghoe Jang1, Virginie Marchal1, Kishore C S Panigrahi1, Stephan Wenkel1,4, Wim Soppe1, Xing-Wang Deng2, Federico Valverde3 and George Coupland1
- Department of Plant Developmental Biology, Max Planck Institute for Plant Breeding Research, Cologne, Germany
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT, USA
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC, Universidad de Sevilla, Sevilla, Spain
Correspondence to:
George Coupland, Department of Plant Developmental Biology, Max Planck Institute for Plant Breeding Research, Carl von Linne Weg 10, Cologne 50829, Germany. Tel.: +49 221 5062 205; Fax: +49 221 5062 207; E-mail: coupland@mpiz-koeln.mpg.de
4Present address: Department of Plant Biology, Carnegie Institution of Washington, 260 Panama Street, Stanford, CA 94305, USA
Received 19 November 2007; Accepted 10 March 2008
Abstract
The transcriptional regulator CONSTANS (CO) promotes flowering of Arabidopsis under long summer days (LDs) but not under short winter days (SDs). Post-translational regulation of CO is crucial for this response by stabilizing the protein at the end of a LD, whereas promoting its degradation throughout the night under LD and SD. We show that mutations in CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1), a component of a ubiquitin ligase, cause extreme early flowering under SDs, and that this is largely dependent on CO activity. Furthermore, transcription of the CO target gene FT is increased in cop1 mutants and decreased in plants overexpressing COP1 in phloem companion cells. COP1 and CO interact in vivo and in vitro through the C-terminal region of CO. COP1 promotes CO degradation mainly in the dark, so that in cop1 mutants CO protein but not CO mRNA abundance is dramatically increased during the night. However, in the morning CO degradation occurs independently of COP1 by a phytochrome B-dependent mechanism. Thus, COP1 contributes to day length perception by reducing the abundance of CO during the night and thereby delaying flowering under SDs.
Keywords:
- CONSTANS,
- flowering,
- photomorphogenesis,
- ubiquitin ligase
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