Regulation of Flowering Time by Trehalose-6-Phoshate Signaling

通过海藻糖-6-磷酸信号调节开花时间

• 批准号: 196338676
• 负责人: Professor Dr. Markus Schmid
• 金额: --
• 依托单位: The James Hutton Institute (JHI)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2011
• 资助国家: 德国
• 起止时间: 2010-12-31 至 2013-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/196338676?language=en
• 关键词: Regulation; Flowering; Time; Trehalose; Phoshate

The induction of flowering is a central event in the life cycle of plants. Because of its importance, flowering is under the control of a complex genetic circuitry that integrates endogenous (hormones, carbohydrates, age) and environmental signals (temperature, photoperiod). Under inductive photoperiod, FLOWERING LOCUS T (FT), a key regulator of flowering time in Arabidopsis thaliana, is induced in the leaf vasculature and acts as a long distance signal to initiate flowering at the shoot meristem. The disaccharide trehalose-6-phosphate (T6P) has been shown to act as signalling molecule in coordinating carbohydrate status with developmental processes. Arabidopsis thaliana plants deficient in the T6P-synthesizing enzyme TREHALOSE-6-PHOSPHATE SYSNTHASE 1 (TPS1) flower extremely late. We recently showed that TPS1/T6P signalling regulates the expression of several flowering-time genes throughout the plant. In the leaf vasculature T6P/TPS1 is absolutely required for the induction of FT, whereas at the shoot apical meristem (SAM) MIR156 and its targets, the SQUAMOSA PROMOTER BINDING PROTEIN LIKE (SPL) genes are targeted by T6P/TPS signalling. Together the environmental (photoperiod) and physiologic (T6P/TPS1) signals ensure that flowering commences only when the conditions are optimal, that is, day length exceeds a certain minimum and the carbohydrate status supports the energy-demanding transition to flowering and seed production. However, many questions regarding the function of T6P/TPS1 remain open.Here we propose a series of experiments with the aim to better integrate T6P/TPS1 signalling into the canonical flowering time pathways. Our preliminary results suggest that T6P/TPS1 regulates flowering in part through the modulation of cell-cycle-dependent SAM maintenance, a previously unexplored aspect that we wish to investigate further. In addition, we have preliminary evidence that T6P/TPS1 affects the ability of plants to respond to changes in ambient temperature as well as chilling (vernalization) treatments. The connection between the T6P/TPS1 pathway and the temperature-dependent regulation of flowering will be analysed. Apart from the above-mentioned analyses that focus on known genes and pathways we will also identify novel components of the T6P/TPS1 signalling pathway. To this end we have already carried out a large-scale mutagenesis screen to identify suppressors of late flowering of the tps1 mutant. As part of the priority program we will identify and characterize in detail the causal genes and place them into the T6P/TPS1 signalling pathway. In summary, the proposed experiments will provide valuable insight into the integration of carbohydrate signalling and flowering time pathways.

开花的诱导是植物生命周期中的一个中心事件。由于其重要性，开花受到复杂的遗传电路的控制，该遗传电路整合了内源性信号（激素、碳水化合物、年龄）和环境信号（温度、光周期）。在诱导光周期下，拟南芥开花时间的关键调节因子 FLOWERING LOCUS T (FT) 在叶片维管系统中被诱导，并充当长距离信号以启动芽分生组织的开花。二糖海藻糖 6-磷酸 (T6P) 已被证明可作为协调碳水化合物状态与发育过程的信号分子。缺乏 T6P 合成酶 TREHALOSE-6-PHOSPHATE SYSNTHASE 1 (TPS1) 的拟南芥植物开花极其晚。我们最近表明 TPS1/T6P 信号传导调节整个植物中几个开花时间基因的表达。在叶脉管系统中，T6P/TPS1 对于诱导 FT 是绝对必需的，而在茎尖分生组织 (SAM) MIR156 及其靶标中，SQUAMOSA PROMOTER BINDING PROTEIN LIKE (SPL) 基因是 T6P/TPS 信号传导的目标。环境（光周期）和生理（T6P/TPS1）信号共同确保只有在最佳条件下才开始开花，即日长超过一定的最小值，并且碳水化合物状态支持向开花和种子生产的能量需求过渡。然而，关于 T6P/TPS1 功能的许多问题仍然悬而未决。在这里，我们提出了一系列实验，旨在更好地将 T6P/TPS1 信号转导整合到规范的开花时间途径中。我们的初步结果表明，T6P/TPS1 部分通过调节细胞周期依赖性 SAM 维持来调节开花，这是我们之前未探索的方面，我们希望进一步研究。此外，我们有初步证据表明 T6P/TPS1 会影响植物对环境温度变化以及低温（春化）处理的反应能力。将分析 T6P/TPS1 途径与温度依赖性开花调节之间的联系。除了上述关注已知基因和通路的分析之外，我们还将鉴定 T6P/TPS1 信号通路的新成分。为此，我们已经进行了大规模的诱变筛选，以确定 tps1 突变体晚花的抑制子。作为优先计划的一部分，我们将详细识别和表征致病基因，并将它们放入 T6P/TPS1 信号通路中。总之，所提出的实验将为碳水化合物信号传导和开花时间途径的整合提供有价值的见解。