Genetic and spatial interactions between FT, TSF and SVP during the early stages of floral induction in Arabidopsis
Genetic and spatial interactions between FT, TSF and SVP during the early stages of floral induction in Arabidopsis
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DOI：
10.1111/j.1365-313x.2009.03986.x
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发表时间：
2009-11-01
期刊：
影响因子：
7.2
通讯作者：
Coupland, George
中科院分区：
文献类型：
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作者：
Jang, Seonghoe;Torti, Stefano;Coupland, George
开花是由一个网络的途径，收敛到调节少数花整合基因控制。我们在拟南芥中研究了这些整合子中的三个之间的相互作用，即FLOW LOCUS T（FT）、FT的孪生姐妹（TSF）和常量过表达的供应者1（SOC 1），以及它们被MADS盒转录因子短营养期（SVP）抑制。FT是一个移动的信号，从叶片传递到分生组织，以启动开花。使用mRNA无效等位基因，我们表明，FT和密切相关的TSF是不是必不可少的开花，但双突变体是光周期不敏感。这两个基因的失活也完全抑制了由CONSTANS（CO）（光周期途径中的转录调节因子）过度表达引起的早花表型。此外，我们表明，TSF和FT具有相似的生化功能，表明它们在酵母中与相同的bZIP转录因子相互作用。从韧皮部伴随细胞特异性启动子的FT或TSF的表达驱动双突变体的早期开花，因此在分生组织中不需要任何基因的表达。此外，TSF，像FT一样，被SVP抑制，但是三重突变体svp-41 ft-10 tsf-1在分生组织中表达SOC 1比ft-10 tsf-1更快，开花更早。因此，我们区分功能的SVP抑制FT和TSF在叶和SOC 1分生组织。此外，一个时间过程中的原位杂交表明，抑制SVP和激活的SOC 1进行同时在分生组织。这些观察结果澄清了这些早期调节花的过渡之间的关系，并进一步强调在叶和分生组织控制开花时间的相关机制。
P>Flowering is controlled by a network of pathways that converge to regulate a small number of floral integrator genes. We studied the interactions in Arabidopsis between three of these integrators, FLOWERING LOCUS T (FT), TWIN SISTER OF FT (TSF) and SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1), as well as their repression by the MADS box transcription factor SHORT VEGETATIVE PHASE (SVP). FT is a mobile signal transmitted from the leaf to the meristem to initiate flowering. Using mRNA null alleles, we show that FT and the closely related TSF are not essential for flowering, but that the double mutant is photoperiod-insensitive. Inactivation of both genes also fully suppresses the early-flowering phenotype caused by over-expression of CONSTANS (CO), a transcriptional regulator in the photoperiod pathway. In addition, we demonstrate that TSF and FT have similar biochemical functions by showing that they interact in yeast with the same bZIP transcription factors. Expression of FT or TSF from promoters specific for phloem companion cells drives early flowering of the double mutant, so no expression of either gene is required in the meristem. Furthermore, TSF, like FT, is repressed by SVP, but the triple mutant svp-41 ft-10 tsf-1 expresses SOC1 in the meristem sooner and flowers earlier than ft-10 tsf-1. Thus we distinguish the functions of SVP in repressing FT and TSF in the leaf and SOC1 in the meristem. In addition, a time course of in situ hybridizations suggested that repression of SVP and activation of SOC1 proceed simultaneously in the meristem. These observations clarify the relationships between these early regulators of the floral transition, and further emphasize the relatedness of mechanisms acting in the leaf and meristem to control flowering time.