Photoreceptor Regulation of CONSTANS Protein in Photoperiodic Flowering

• Published in: Science (American Association for the Advancement of Science) 2004-02, Vol.303 (5660), p.1003-1006
• Main Authors: Valverde, Federico, Mouradov, Aidyn, Soppe, Wim, Ravenscroft, Dean, Samach, Alon, Coupland, George
• Format: Article
• Language: English
• Subjects: Antibodies; Arabidopsis - genetics; Arabidopsis - growth & development; Arabidopsis - physiology; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Arabidopsis thaliana; Biological and medical sciences; Biology and morphogenesis of the reproductive apparatus. Photoperiodism, vernalisation; Cell Nucleus - metabolism; Circadian Rhythm; CONSTANS gene; Cryptochromes; Cysteine Endopeptidases - metabolism; Darkness; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Drosophila Proteins; Eye Proteins; Flavoproteins - genetics; Flavoproteins - metabolism; Flowering; Flowers & plants; Flowers - growth & development; Fundamental and applied biological sciences. Psychology; Gene expression regulation; Gene Expression Regulation, Plant; Genes; Genetic aspects; Light; Luminescence; Messenger RNA; Multienzyme Complexes - metabolism; Mutation; Photoperiod; Photoreceptor Cells; Photoreceptor Cells, Invertebrate; Photoreceptors; Photosynthetic Reaction Center Complex Proteins - genetics; Photosynthetic Reaction Center Complex Proteins - metabolism; Phytochrome - genetics; Phytochrome - metabolism; Phytochrome A; Phytochrome B; Plant flowering; Plant growth regulators; Plant physiology and development; Plants; Plants, Flowering of; Plants, Genetically Modified; Proteasome Endopeptidase Complex; Proteins; Receptors, G-Protein-Coupled; Recombinant Fusion Proteins - metabolism; RNA, Messenger - genetics; RNA, Messenger - metabolism; RNA, Plant - genetics; RNA, Plant - metabolism; Transcription Factors - genetics; Transcription Factors - metabolism; Transcription, Genetic; Ubiquitin - metabolism; Vegetative and sexual reproduction, floral biology, fructification
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1091761

Many plants flower in response to seasonal fluctuations in day length. The CONSTANS (CO) gene of Arabidopsis promotes flowering in long days. Flowering is induced when CO messenger RNA expression coincides with the exposure of plants to light. However, how this promotes CO activity is unknown. We show that light stabilizes nuclear CO protein in the evening, whereas in the morning or in darkness the protein is degraded by the proteasome. Photoreceptors regulate CO stability and act antagonistically to generate daily rhythms in CO abundance. This layer of regulation refines the circadian rhythm in CO messenger RNA and is central to the mechanism by which day length controls flowering.