14-3-3 proteins act as intracellular receptors for rice Hd3a florigen
14-3-3 proteins act as intracellular receptors for rice Hd3a florigen
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DOI：
10.1038/nature10272
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发表时间：
2011-08-18
期刊：
影响因子：
64.8
通讯作者：
Shimamoto, Ko
中科院分区：
文献类型：
--
作者：
Taoka, Ken-ichiro;Ohki, Izuru;Shimamoto, Ko
75年前提出了“成花素”（1）在叶子中合成并运输到茎尖，在那里它诱导开花。直到最近，遗传和生物化学研究才确定成花素是由FLOWERLOCUS T（FT）编码的，这是一种在高等植物中普遍保守的基因（2-4）。尽管如此，成花素在成花诱导过程中的确切功能仍然知之甚少，成花素的受体尚未确定。在这里，我们发现水稻FT同源物Hd 3a（5）与芽顶端细胞中的14-3-3蛋白相互作用，产生一个易位到细胞核并结合到水稻（Os）FD 1转录因子（拟南芥FD的水稻同源物）的复合物。由此产生的三元“成花素激活复合物”（FAC）诱导A. thaliana APETALA 1（AP 1），导致开花。我们确定了水稻FAC的2.4埃晶体结构，这为成花素在开花中的作用提供了机理依据。本研究结果表明，14-3-3蛋白在植物茎尖细胞中是成花因子的胞内受体，为调控植物开花提供了新的途径。
'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(2-4). 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 angstrom 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.