Uncovering the control of leaf starch degradation

揭示叶淀粉降解的控制

• 批准号: BB/L008378/1
• 负责人: Alison Smith
• 金额: $ 69.96万
• 依托单位: John Innes Centre
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2014
• 资助国家: 英国
• 起止时间: 2014 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FL008378%2F1
• 关键词: Uncovering; control; leaf; starch; degradation

Plants feed themselves by converting carbon dioxide from the air into sugars, in the process of photosynthesis. These sugars provide the energy and building blocks for plant growth. Although photosynthesis can only happen in the light, most plants continue to grow at night. They are able to do this because some of the sugars made during the day are stored in leaves as starch. At night, the starch is broken down to release sugars that can be used for growth. We have discovered that plants control very precisely the rate at which starch is broken down to release sugars during the night, so that the supply of starch lasts precisely until the dawn when photosynthesis starts again. This control is very important, because mutant plants that run out of starch before dawn are unable to grow for the last part of the night. They are therefore less productive overall than normal plants. Remarkably, we have shown that the plant must be able to anticipate the length of the night and to do arithmetic in order to achieve this. When it gets dark, the plant measures the amount of starch it has, estimates the time until dawn, then divides the amount of starch by the length of time for which it must last in order to set the correct rate of breakdown to release sugars. We know that the length of time until dawn is measured by the plant's internal circadian clock, but we have very little knowledge of other aspects of the arithmetic division mechanism. The aim of this project is to discover more about how it works. To discover what genes and proteins are involved in the mechanism, we have produced plants that glow in the dark when they run out of starch and stop growing. This achievement means that we can now identify mutant plants that run out of starch at the wrong time; they will glow earlier or later during the night than normal plants. The mutant plants will have defects in genes needed for the arithmetic division mechanism. By identifying the defective genes we will be able to piece together how the arithmetic division mechanism works, and so understand how plants are able to grow all through the night.

在光合作用过程中，植物通过将二氧化碳从空气转化为糖。这些糖为植物生长提供了能量和基础。尽管光合作用只能在光线下发生，但大多数植物在晚上继续生长。他们之所以能够这样做，是因为白天制造的某些糖作为淀粉存储在叶子中。到了晚上，淀粉被分解以释放可用于生长的糖。我们已经发现，植物可以非常精确地控制淀粉分解以在夜间释放糖的速度，以便淀粉的供应持续到精确直至光合作用再次开始时黎明为止。这种控制非常重要，因为在黎明前的最后一部分黎明之前，突变的植物无法生长。因此，它们的总体生产力低于普通植物。值得注意的是，我们已经表明，植物必须能够预测夜晚的长度并进行算术以实现这一目标。当变黑时，植物可以测量其淀粉的量，估计黎明的时间，然后将淀粉的量除以必须持续的时间，以便将正确的分解率设置为释放糖。我们知道，黎明的时间长度是由植物内部昼夜节律衡量的，但是我们对算术分裂机制的其他方面知识很少。该项目的目的是更多地发现有关其工作原理的更多信息。为了发现该机制涉及哪些基因和蛋白质，我们生产的植物在淀粉耗尽并停止生长时会在黑暗中发光。这项成就意味着我们现在可以识别出在错误的时间少量淀粉的突变植物。它们会比普通植物早或晚些时候发光。突变植物将在算术分裂机理所需的基因中存在缺陷。通过识别有缺陷的基因，我们将能够将算术分裂机制的工作原理拼凑在一起，从而了解植物如何在整夜生长。

项目成果

Leaf Starch Turnover Occurs in Long Days and in Falling Light at the End of the Day

• DOI: 10.1104/pp.17.00601
• 发表时间: 2017-08-01
• 期刊: PLANT PHYSIOLOGY
• 影响因子: 7.4
• 作者: Fernandez, Olivier;Ishihara, Hirofumi;Stitt, Mark
• 通讯作者: Stitt, Mark

The Arabidopsis Framework Model version 2 predicts the organism-level effects of circadian clock gene mis-regulation

拟南芥框架模型版本 2 预测生物钟基因失调的生物体水平影响

• DOI: 10.1101/105437
• 发表时间: 2017
• 作者: Chew Y