title: 14-3-3 proteins act as intracellular receptors for rice Hd3a florigen.
abstract: 'Florigen' was proposed 75 years ago 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. 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 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.
authors.affiliation: Laboratory of Plant Molecular Genetics, Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan.
authors.forename: Ken-ichiro
authors.initials: K
authors.lastname: Taoka
authors.forename: Izuru
authors.initials: I
authors.lastname: Ohki
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tsuji
authors.forename: Kyoko
authors.initials: K
authors.lastname: Furuita
authors.forename: Kokoro
authors.initials: K
authors.lastname: Hayashi
authors.forename: Tomoko
authors.initials: T
authors.lastname: Yanase
authors.forename: Midori
authors.initials: M
authors.lastname: Yamaguchi
authors.forename: Chika
authors.initials: C
authors.lastname: Nakashima
authors.forename: Yekti Asih
authors.initials: YA
authors.lastname: Purwestri
authors.forename: Shojiro
authors.initials: S
authors.lastname: Tamaki
authors.forename: Yuka
authors.initials: Y
authors.lastname: Ogaki
authors.forename: Chihiro
authors.initials: C
authors.lastname: Shimada
authors.forename: Atsushi
authors.initials: A
authors.lastname: Nakagawa
authors.forename: Chojiro
authors.initials: C
authors.lastname: Kojima
authors.forename: Ko
authors.initials: K
authors.lastname: Shimamoto
mesh_terms: D048948:14-3-3 Proteins / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry; D002135:Calcium-Binding Proteins / Q000737:chemistry; D002467:Cell Nucleus / Q000378:metabolism; D035264:Flowers / Q000254:growth & development* / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D026161:MADS Domain Proteins / Q000737:chemistry; D008958:Models, Molecular; D046912:Multiprotein Complexes / Q000737:chemistry / Q000378:metabolism; D012275:Oryza / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018520:Plant Shoots / Q000166:cytology; D011485:Protein Binding; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000737:chemistry; D020798:Two-Hybrid System Techniques
chemical_list: D048948:14-3-3 Proteins; C091535:AP1 protein, Arabidopsis; D029681:Arabidopsis Proteins; D002135:Calcium-Binding Proteins; C503117:FD protein, Arabidopsis; C418905:FT protein, Arabidopsis; C087620:GF14 protein, Arabidopsis; D026161:MADS Domain Proteins; D046912:Multiprotein Complexes; D010940:Plant Proteins; D014157:Transcription Factors