Dynamical feedback between circadian clock and sucrose availability explains adaptive response of starch metabolism to various photoperiods.
Dynamical feedback between circadian clock and sucrose availability explains adaptive response of starch metabolism to various photoperiods.
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DOI：
10.3389/fpls.2012.00305
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发表时间：
2012
影响因子：
5.6
通讯作者：
Satake A
中科院分区：
文献类型：
--
作者：
Feugier FG;Satake A
植物在其整个生命周期中都在进行资源管理。白天，它们以光合碳、蔗糖为食，同时将一部分储存在淀粉中供夜间使用。仔细控制碳分配、淀粉降解和蔗糖出口率对于避免碳饥饿至关重要，确保在任何光周期下都能实现最佳生长。对这些关键代谢率的有效调节可以为植物带来进化优势。在这里，我们提出了响应各种光周期的适应性淀粉代谢模型。我们假设叶子中的三个关键代谢率受到昼夜节律调节，并且它们的振荡阶段因蔗糖饥饿而发生变化。我们对各种光周期条件进行梯度下降，以找到相应的最佳相移组，从而最大限度地减少饥饿。收敛结果均与实验数据一致：（1）昼夜淀粉谱呈白天线性增加、夜间线性减少； (2)较短的光周期往往会增加淀粉的合成速度，而较长的夜晚则会降低淀粉的降解速度； (3) 突然的早黄昏表明在较长的夜晚淀粉降解速度较慢。最能解释观察结果的概况与所有速率的昼夜节律调节相对应。这项理论研究将为未来淀粉代谢与生物钟以及植物生产力之间的反馈研究建立框架。
Plants deal with resource management during all their life. During the day they feed on photosynthetic carbon, sucrose, while storing a part into starch for night use. Careful control of carbon partitioning, starch degradation, and sucrose export rates is crucial to avoid carbon starvation, insuring optimal growth whatever the photoperiod. Efficient regulation of these key metabolic rates can give an evolutionary advantage to plants. Here we propose a model of adaptive starch metabolism in response to various photoperiods. We assume the three key metabolic rates to be circadian regulated in leaves and that their phases of oscillations are shifted in response to sucrose starvation. We performed gradient descents for various photoperiod conditions to find the corresponding optimal sets of phase shifts that minimize starvation. Results at convergence were all consistent with experimental data: (1) diurnal starch profile showed linear increase during the day and linear decrease at night; (2) shorter photoperiod tended to increase starch synthesis speed while decreasing its degradation speed during the longer night; (3) sudden early dusk showed slower starch degradation during the longer night. Profiles that best explained observations corresponded to circadian regulation of all rates. This theoretical study would establish a framework for future research on feedback between starch metabolism and circadian clock as well as plant productivity.
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影响因子：
56.9
作者：
Harmer, SL;Hogenesch, LB;Kay, SA
通讯作者：
Kay, SA
影响因子：
9.9
作者：
通讯作者：
--
影响因子：
7.4
作者：
Smith, SM;Fulton, DC;Smith, AM
通讯作者：
Smith, AM
影响因子：
56.9
作者：
James, Allan B.;Monreal, Jose A.;Nimmo, Hugh G.
通讯作者：
Nimmo, Hugh G.
影响因子：
7.4
作者：
Knight, Heather;Thomson, Adrian J. W.;McWatters, Harriet G.
通讯作者：
McWatters, Harriet G.