Tylewicz Szymon, Tsuji Hiroyuki, Miskolczi Pál, Petterle Anna, Azeez Abdul, Jonsson Kristoffer, Shimamoto Ko, Bhalerao Rishikesh P
Umea Plant Science Center, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, S-901 87 Umea, Sweden;
Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan; and.
Proc Natl Acad Sci U S A. 2015 Mar 10;112(10):3140-5. doi: 10.1073/pnas.1423440112. Epub 2015 Feb 23.
A complex consisting of evolutionarily conserved FD, flowering locus T (FT) proteins is a regulator of floral transition. Intriguingly, FT orthologs are also implicated in developmental transitions distinct from flowering, such as photoperiodic control of bulbing in onions, potato tuberization, and growth cessation in trees. However, whether an FT-FD complex participates in these transitions and, if so, its mode of action, are unknown. We identified two closely related FD homologs, FD-like 1 (FDL1) and FD-like 2 (FDL2), in the model tree hybrid aspen. Using gain of function and RNAi-suppressed FDL1 and FDL2 transgenic plants, we show that FDL1 and FDL2 have distinct functions and a complex consisting of FT and FDL1 mediates in photoperiodic control of seasonal growth. The downstream target of the FT-FD complex in photoperiodic control of growth is Like AP1 (LAP1), a tree ortholog of the floral meristem identity gene APETALA1. Intriguingly, FDL1 also participates in the transcriptional control of adaptive response and bud maturation pathways, independent of its interaction with FT, presumably via interaction with abscisic acid insensitive 3 (ABI3) transcription factor, a component of abscisic acid (ABA) signaling. Our data reveal that in contrast to its primary role in flowering, FD has dual roles in the photoperiodic control of seasonal growth and stress tolerance in trees. Thus, the functions of FT and FD have diversified during evolution, and FD homologs have acquired roles that are independent of their interaction with FT.
由进化上保守的FD和开花位点T（FT）蛋白组成的复合物是花转变的调节因子。有趣的是，FT直系同源物也参与了与开花不同的发育转变，例如洋葱鳞茎形成的光周期控制、马铃薯块茎形成以及树木生长停止。然而，FT-FD复合物是否参与这些转变，如果参与，其作用模式尚不清楚。我们在模式树杂种山杨中鉴定出两个密切相关的FD同源物，类FD1（FDL1）和类FD2（FDL2）。通过功能获得和RNA干扰抑制FDL1和FDL2的转基因植物，我们表明FDL1和FDL2具有不同的功能，并且由FT和FDL1组成的复合物介导了季节性生长的光周期控制。FT-FD复合物在生长光周期控制中的下游靶标是类AP1（LAP1），它是花分生组织特征基因APETALA1的树木直系同源物。有趣的是，FDL1还参与适应性反应和芽成熟途径的转录控制，与其与FT的相互作用无关，推测是通过与脱落酸不敏感3（ABI3）转录因子相互作用，ABI3是脱落酸（ABA）信号传导的一个组分。我们的数据表明，与它在开花中的主要作用相反，FD在树木季节性生长的光周期控制和胁迫耐受性中具有双重作用。因此，FT和FD的功能在进化过程中已经多样化，并且FD同源物已经获得了与其与FT相互作用无关的作用。
