Day Length Signalling and Crosstalk Between Cytoplasmic and Chloroplastic Calcium Oscillations in Arabidopsis thaliana

粮食、水果、蔬菜的生产是靠开花的，没有花就没有农业。植物仔细控制开花时间，以优化授粉和资源，从而最大限度地提高种子产量。开花在一年中非常精确的时间，但这是如何实现的仍然是一个谜。自20世纪30年代初S以来，人们就知道植物通过比较内部时钟的滴答声和它们在一年中不同时间所经历的日长来记录季节。然而，我们仍然对这种内部起搏器和日长之间的信号是如何感知和理解的知之甚少。这个项目将研究使植物在可能的最佳时间开花的关键过程。我将研究钙信号通路参与协调开花时间的假说。钙是植物体内一种重要的信号分子。我之前已经证明，内部计时器产生的钙振荡是由昼夜的相对持续时间决定的。其他实验室的研究表明，在夜幕降临时，叶绿体(发生光合作用的细胞器)中的钙突然增加。我认为，这两个钙信号之间的共生，或者说‘串扰’，涉及到花的定时。为了研究这种可能性，我将开发新的重组技术来操纵活植物中的钙并对其进行成像。我将把这些技术与开花时间基因的分子分析和经典的生理学方案结合起来，阐明钙在开花时间中的作用。这项研究将导致对开花季节性的新的、重要的见解，并将在农业中广泛应用。例如，作物的开花时间可以延长到整个季节，以避免供过于求，从而减少浪费、储存成本和进口需求。因此，通过精准农业控制开花时间可能会改善作物管理做法，生产出更高质量的食品，使农民、消费者和环境受益。

The production of grain, fruit and vegetables relies on flowering; without flowers, therefore, there would be no agriculture. Plants carefully control the timing of flowering to optimise pollination and resources, and thereby maximise seed production. Flowering occurs at very precise times of the year, but how this is achieved remains a mystery. Since the early 1930's it has been known that plants keep track of the seasons by comparing the ticking of an internal chronometer to the day length they experience at different times of the year. However, we still know very little about how the signals between this internal pacemaker and day length are perceived and understood. This project will research that critical process which allows plants to flower at the best possible time. I will investigate the hypothesis that calcium-signalling pathways are involved in coordinating flowering time. Calcium is an essential signalling molecule in plants. I have previously shown that the internal chronometer generates calcium oscillations that are shaped by the relative duration of days and nights. Work in other laboratories has shown that a sudden calcium increase occurs in the chloroplasts (the organelles where photosynthesis occurs), at nightfall. I propose that co-incidence, or 'crosstalk' between these two calcium signals is involved in floral timing. To investigate this possibility, I will develop new recombinant techniques for manipulating and imaging calcium in living plants. I will combine these technologies with molecular analysis of flowering time genes and classic physiological protocols to elucidate the role of calcium in flowering time. This research will lead to new, important insights into the seasonality of flowering that will have general application to agriculture. For example, the flowering of crops may be extended over a whole season to avoid gluts, reducing waste, storage costs and the need for imports. Controlling flowering time by precision agriculture may therefore result in improved crop management practices and the production of higher quality food that will benefit the farmer, the consumer and the environment.