14-3-3 proteins act as intracellular receptors for rice Hd3a florigen

• Published in: Nature (London) Vol. 476; no. 7360; pp. 332 - 335
• Main Authors: Taoka, Ken-ichiro, Ohki, Izuru, Tsuji, Hiroyuki, Furuita, Kyoko, Hayashi, Kokoro, Yanase, Tomoko, Yamaguchi, Midori, Nakashima, Chika, Purwestri, Yekti Asih, Tamaki, Shojiro, Ogaki, Yuka, Shimada, Chihiro, Nakagawa, Atsushi, Kojima, Chojiro, Shimamoto, Ko
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 18.08.2011; Nature Publishing Group
• Subjects: 14-3-3 Proteins - metabolism; 631/337/572; 631/449/2679/2681; 631/45/535; Agronomy. Soil science and plant productions; Amino acids; Arabidopsis Proteins - chemistry; Biological and medical sciences; Calcium-Binding Proteins - chemistry; Cell Nucleus - metabolism; Cytoplasm; Experiments; Flowers - growth & development; Flowers - metabolism; Frequency distribution; Fundamental and applied biological sciences. Psychology; Gene expression; Gene Expression Regulation, Plant; Genetic aspects; Genetics and breeding of economic plants; Humanities and Social Sciences; letter; MADS Domain Proteins - chemistry; Models, Molecular; multidisciplinary; Multiprotein Complexes - chemistry; Multiprotein Complexes - metabolism; Oryza - genetics; Oryza - growth & development; Oryza - metabolism; Physiological aspects; Plant proteins; Plant Proteins - chemistry; Plant Proteins - genetics; Plant Proteins - metabolism; Plant Shoots - cytology; Polymerase chain reaction; Protein Binding; Proteins; Rice; Science; Science (multidisciplinary); Sequence Homology, Amino Acid; Transcription Factors - chemistry; Two-Hybrid System Techniques; Yeast; Japan; Monocotyledones; Activation; Biochemistry; Cereal crop; Arabidopsis thaliana; Induced flowering; Oryza sativa; Gene; Cruciferae; Gramineae; Dicotyledones; Angiospermae; Flowering; Genetics; Transcription factor; Locus; Apex; Biological receptor; Translocation; Protein; Spermatophyta; Intracellular; Phytohormone; Experimental plant; Shoot
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/nature10272

How florigen says it with flowers Florigen, a plant hormone that translocates from leaves to the shoot apex to induce flowering, is encoded by the FLOWERING LOCUS T ( FT ) gene. The detailed molecular mechanism for florigen action and the identity of its receptors remained unknown. Ko Shimamoto and colleagues show that in rice, florigen binds to 14-3-3 proteins, a type of regulatory molecule present in all eukaryotic cells, and to the transcription factor OsFD1. The crystal structure of the resulting florigen activation complex (FAC) has been determined, providing a mechanistic basis for florigen function in flowering. This work offers clues for improving agriculturally important traits by manipulating florigen and its regulators. ‘Florigen’ was proposed 75 years ago 1 to be synthesized in the leaf and transported to the shoot apex, where it induces flowering. Only recently have genetic and biochemical studies established that florigen is encoded by FLOWERING LOCUS T ( FT ), a gene that is universally conserved in higher plants 2 , 3 , 4 . Nonetheless, the exact function of florigen during floral induction remains poorly understood and receptors for florigen have not been identified. Here we show that the rice FT homologue Hd3a 5 interacts with 14-3-3 proteins in the apical cells of shoots, yielding a complex that translocates to the nucleus and binds to the Oryza sativa (Os)FD1 transcription factor, a rice homologue of Arabidopsis thaliana FD. The resultant ternary ‘florigen activation complex’ (FAC) induces transcription of OsMADS15 , a homologue of A. thaliana APETALA1 ( AP1 ), which leads to flowering. We have determined the 2.4 Å crystal structure of rice FAC, which provides a mechanistic basis for florigen function in flowering. Our results indicate that 14-3-3 proteins act as intracellular receptors for florigen in shoot apical cells, and offer new approaches to manipulate flowering in various crops and trees.