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.

植物通过光合作用将空气中的二氧化碳转化为糖来喂养自己。这些糖为植物生长提供能量和基础材料。虽然光合作用只能在光照下进行，但大多数植物在夜间继续生长。它们之所以能做到这一点，是因为白天产生的一些糖以淀粉的形式储存在树叶中。在晚上，淀粉被分解，释放出用于生长的糖。在一天结束的时候，随着天黑，植物必须从光合作用转向淀粉分解，作为它们生长所需的糖的来源。我们知道这种转换在黄昏时逐渐发生。随着光线减弱，光合作用产生的糖供应减少，淀粉产生的糖供应逐渐增加。然而，对于植物如何实现从光合作用到淀粉分解作为糖的来源这一转变，我们几乎一无所知。我们已经发现，淀粉的分解是由一天结束时光线的下降引起的。然而，令人惊讶的是，同样的亮度下降并没有在白天引发淀粉的分解。这一发现表明，植物有一种复杂的机制，可以预测夜晚何时到来，并在那个时刻触发淀粉分解，以应对光线的下降。在这个项目中，我们将研究下降的光照水平如何触发淀粉分解，以及这个过程的时间是否由植物的内部时钟（生物钟）控制。这项研究将利用突变植物，这些植物要么感知光线水平的能力降低，要么内部时钟的功能发生了变化。研究结果将提供有关植物如何在昼夜循环中保持生长的新信息，并深入了解不同的光照制度如何影响植物生产力。

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