FKF1 Conveys Timing Information for CONSTANS Stabilization in Photoperiodic Flowering

• Published in: Science (American Association for the Advancement of Science) 2012-05, Vol.336 (6084), p.1045-1049
• Main Authors: Song, Young Hun, Smith, Robert W., To, Benjamin J., Millar, Andrew J., Imaizumi, Takato
• Format: Article
• Language: English
• Subjects: Actins; Agronomy. Soil science and plant productions; Arabidopsis - genetics; Arabidopsis - growth & development; Arabidopsis - metabolism; Arabidopsis - physiology; Arabidopsis Proteins - chemistry; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Binding; Biological and medical sciences; Crop harvesting; Cumulative distribution functions; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Flowering; Flowers - growth & development; Fundamental and applied biological sciences. Psychology; Gene expression; Gene expression regulation; Gene Expression Regulation, Plant; Genes; Genetics and breeding of economic plants; Light; Logical Thinking; Messenger RNA; Modeling; Models, Biological; Mutation; Photoperiod; Physiological regulation; Plants; Plants, Genetically Modified; Promoter Regions, Genetic; Protein Binding; Protein Interaction Domains and Motifs; Protein Stability; Proteins; Releasing; Repressor Proteins - metabolism; RNA, Messenger - genetics; RNA, Messenger - metabolism; RNA, Plant - genetics; RNA, Plant - metabolism; Shoring; Stabilization; Transcription Factors - genetics; Transcription Factors - metabolism; Transcription, Genetic; Transcriptional regulatory elements
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1219644

Plants use day-length information to coordinate flowering time with the appropriate season to maximize reproduction. In Arabidopsis, the long day-specific expression of CONSTANS (CO) protein is crucial for flowering induction. Although light signaling regulates CO protein stability, the mechanism by which CO is stabilized in the long-day afternoon has remained elusive. Here, we demonstrate that FLAVIN-BINDING, KELCH REPEAT, F-BOX 1 (FKF1) protein stabilizes CO protein in the afternoon in long days. FKF1 interacts with CO through its LOV domain, and blue light enhances this interaction. In addition, FKF1 simultaneously removes CYCLING DOF FACTOR 1 (CDF1), which represses CO and FLOWERING LOCUS T (FT) transcription. Together with CO transcriptional regulation, FKF1 protein controls robust FT mRNA induction through multiple feedforward mechanisms that accurately control flowering timing.