The twilight zone: the initiation of starch degradation in leaves

暮光区：叶子中淀粉降解的开始

• 批准号: BB/N001389/1
• 负责人: Alison Smith
• 金额: $ 67.88万
• 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: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FN001389%2F1
• 关键词: twilight; zone; initiation; 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. At the end of the day, as it gets dark, plants must switch from photosynthesis to starch breakdown as their source of sugars for growth. We know that this switch happens gradually during twilight. As the light fades and the supply of sugars from photosynthesis goes down, the supply of sugars from starch gradually increases. However, almost nothing is known about how plants bring about this transition from photosynthesis to starch breakdown as the source of sugars. We have discovered that starch breakdown is triggered by falling light levels at the end of the day. Surprisingly, however, the same fall in light levels does not trigger starch breakdown in the middle of the day. This discovery implies that plants have a sophisticated mechanism that anticipates when the night will come, and triggers starch breakdown in response to falling light levels only at that point. During this project, we will investigate how falling light levels trigger starch breakdown, and whether the timing of this process is controlled by the plant's internal clock (the circadian clock). The research will make use of mutant plants that have either a reduced ability to perceive light levels, or alterations in the functioning of their internal clock. The outcomes will be new information about how plants maintain their growth throughout the day night cycle, and insights into how different light regimes may affect plant productivity.

植物通过在光合作用过程中将空气中的二氧化碳转化为糖来自我维持。这些糖为植物生长提供能量和组成部分。虽然光合作用只能在光照下进行，但大多数植物在夜间仍能继续生长。它们之所以能够做到这一点，是因为白天产生的一些糖以淀粉的形式储存在叶子中。晚上，淀粉被分解，释放出可用于生长的糖。一天结束时，天黑了，植物必须从光合作用转向淀粉分解，作为生长所需的糖源。我们知道这种转变在黄昏时逐渐发生。随着光线变暗，光合作用提供的糖分减少，淀粉提供的糖分逐渐增加。然而，人们对植物如何实现从光合作用到淀粉分解作为糖源的转变几乎一无所知。我们发现淀粉分解是由一天结束时光照水平下降引发的。然而，令人惊讶的是，同样的光照水平下降并不会在中午引发淀粉分解。这一发现意味着植物具有复杂的机制，可以预测夜晚何时到来，并仅在该时刻响应光线强度的下降而触发淀粉分解。在这个项目中，我们将研究降低的光照水平如何触发淀粉分解，以及该过程的时间是否由植物的内部时钟（生物钟）控制。该研究将利用突变植物，这些植物要么感知光水平的能力降低，要么改变其内部时钟的功能。结果将是关于植物如何在昼夜周期中保持生长的新信息，以及对不同光照状况如何影响植物生产力的见解。

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

Rising rates of starch degradation during daytime and trehalose 6-phosphate optimize carbon availability.

• DOI: 10.1093/plphys/kiac162
• 发表时间: 2022-08-01
• 期刊: PLANT PHYSIOLOGY
• 影响因子: 7.4
• 作者: Ishihara, Hirofumi;Alseekh, Saleh;Feil, Regina;Perera, Pumi;George, Gavin M.;Niedzwiecki, Piotr;Arrivault, Stephanie;Zeeman, Samuel C.;Fernie, Alisdair R.;Lunn, John E.;Smith, Alison M.;Stitt, Mark
• 通讯作者: Stitt, Mark

Sucrose synthases are not involved in starch synthesis in Arabidopsis leaves.

• DOI: 10.1038/s41477-022-01140-y
• 发表时间: 2022-05
• 期刊: NATURE PLANTS
• 影响因子: 18
• 作者: Funfgeld, Maximilian M. F. F.;Wang, Wei;Ishihara, Hirofumi;Arrivault, Stephanie;Feil, Regina;Smith, Alison M.;Stitt, Mark;Lunn, John E.;Niittyla, Totte
• 通讯作者: Niittyla, Totte