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

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Ken-ichiro Taoka, Izuru Ohki, Hiroyuki Tsuji, Kyoko Furuita, Kokoro Hayashi, Tomoko Yanase, Midori Yamaguchi, Chika Nakashima, Yekti Asih Purwestri, Shojiro Tamaki, Yuka Ogaki, Chihiro Shimada, Atsushi Nakagawa, Chojiro Kojima, Ko Shimamoto
Nature, 2011, 476(7360): 332-335  DOI: 10.1038/nature10272;      追溯原文......本站官方QQ群:62473826

'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 2.4Å 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.

14-3-3蛋白起水稻成花素受体的作用

成花素的概念在75年就已经提出,它在叶中合成然后转移到茎顶端并诱导开花。近些年,我们从遗传和生化角度研究了编码成花素的基因FT,该基因在高等植物中非常保守。但是,在花诱导阶段对成花素的确切功能我们还知之甚少。本文中,我们发现水稻Hd3a蛋白(与FT同源)能与14-3-3蛋白在茎顶端细胞中互作,互作形成的复合物转运至核内,与转录因子OsFD1结合,产生的三体“成花素激活复合物(FAC)”能诱导OsMADS15(与拟南芥AP1同源)转录,促进开花。我们还提供了FAC复合物2.4A的晶体结构。这为成花素在开花上的功能提供了一个生化依据。我们的结论表明14-3-3蛋白是成花素的胞内受体,这为操控各种作物和树木的开花提供了新的方法。


基因列表
  成花素基因;抽穗期基因;生育期基因;光周期敏感基因;感光基因 Hd3a; FT
  14-3-3蛋白 GF14c; 14-3-3
  bZIP转录因子 OsFD1; OsbZIP77