School of BioSciences, The University of Melbourne, Parkville 3010, Australia
Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom.
Plant Physiol. 2017 Oct;175(2):947-958. doi: 10.1104/pp.17.00592. Epub 2017 Aug 4.
Circadian clocks drive rhythmic physiology and metabolism to optimize plant growth and performance under daily environmental fluctuations caused by the rotation of the planet. Photosynthesis is a key metabolic process that must be appropriately timed to the light-dark cycle. The circadian clock contributes to the regulation of photosynthesis, and in turn the daily accumulation of sugars from photosynthesis also feeds back to regulate the circadian oscillator. We have previously shown that () is required to sustain Suc-dependent circadian rhythms in darkness. The mechanism by which Suc affects the circadian oscillator in a -dependent manner was unknown. Here, we identify that Suc sustains rhythms in the dark by stabilizing GI protein, dependent on the F-box protein , and implicate (), a negative regulator of ethylene signaling. Our identification of a role for CTR1 in the response to Suc prompted a reinvestigation of the effects of ethylene on the circadian oscillator. We demonstrate that ethylene shortens the circadian period, conditional on the effects of Suc and requiring These findings reveal that Suc affects the stability of circadian oscillator proteins and can mask the effects of ethylene on the circadian system, identifying novel molecular pathways for input of sugar to the Arabidopsis () circadian network.
生物钟驱动着生理和代谢的节律性，以优化植物在行星旋转引起的日常环境波动下的生长和表现。光合作用是一种关键的代谢过程，必须与光暗周期相适应。生物钟有助于调节光合作用，而光合作用产生的糖分的日积累也反过来反馈调节生物钟振荡器。我们之前已经表明，（）是维持黑暗中依赖蔗糖（Suc）的生物钟节律所必需的。蔗糖以依赖（）的方式影响生物钟振荡器的机制尚不清楚。在这里，我们确定蔗糖通过稳定 GI 蛋白在黑暗中维持节律，该过程依赖于 F-box 蛋白（），并暗示（），乙烯信号转导的负调节剂。我们鉴定出 CTR1 在对蔗糖的反应中的作用，促使我们重新研究乙烯对生物钟振荡器的影响。我们证明，乙烯缩短了生物钟周期，这是有条件的，取决于蔗糖的作用，并且需要（）。这些发现表明，蔗糖会影响生物钟振荡器蛋白的稳定性，并可以掩盖乙烯对生物钟系统的影响，从而确定了糖进入拟南芥（）生物钟网络的新的分子途径。
