The circadian clock regulates auxin signaling and responses in Arabidopsis.
The circadian clock regulates auxin signaling and responses in Arabidopsis.
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DOI：
10.1371/journal.pbio.0050222
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发表时间：
2007-08
期刊：
影响因子：
9.8
通讯作者：
Harmer SL
中科院分区：
文献类型：
--
作者：
Covington MF;Harmer SL
生物钟在植物生理、环境反应和发育的时间调控中起着普遍的作用。相反，植物激素生长素在植物生长发育的空间调控中发挥着同样深远的作用。Went和Thimann在70年前就注意到植物对生长素的敏感性随着一天中的时间而变化，他们无法解释这一观察结果。在这里，我们提出了解释这个谜题的工作，证明生物钟调节生长素信号转导。利用全基因组转录谱分析，我们发现许多生长素诱导的基因受到时钟调控。我们证实内源性生长素信号是通过基于荧光素酶的测定进行时钟调节的。外源生长素对植物生物钟的影响不大，但生物钟控制着植物对生长素的敏感性。值得注意的是，我们发现对外源生长素的转录和生长反应都是由生物钟控制的。因此，生物钟调节着生长素的部分反应，也许是全部反应。因此，以前认为不受昼夜节律控制的植物生理学的许多方面可能显示出一天中特定时间的敏感性，这可能对植物生长和环境反应产生重要影响。大多数高等生物，包括植物和动物，已经发展出一种计时机制，使它们能够预测光和温度等环境参数的每日波动。这种生物钟通过在大约24小时的周期内产生自我维持的基因表达节奏，有效地协调植物的生长和代谢。生长素是确定植物生长和发育的空间模式的主要贡献者之一，它是植物发育几乎所有阶段所必需的激素。生长素还能帮助植物根据光照、重力和水分等环境因素做出正确的定位。我们现在已经发现生长素信号通路从合成到反应的几乎每一步都有昼夜调节的成分表达。我们通过展示植物在一天中的不同时间对生长素的不同敏感性来证明这一观察的相关性：生物钟在转录水平和茎生长水平上控制植物对生长素的敏感性。我们的工作证明了生物钟和生长素信号通路之间的密切联系，并表明其他生长素调节的过程也可能受到昼夜节律的控制。生长素反应的昼夜节律调节表明，植物生理学的许多方面以前不被认为是受昼夜节律控制的，可能表现出一天中特定时间的敏感性。
The circadian clock plays a pervasive role in the temporal regulation of plant physiology, environmental responsiveness, and development. In contrast, the phytohormone auxin plays a similarly far-reaching role in the spatial regulation of plant growth and development. Went and Thimann noted 70 years ago that plant sensitivity to auxin varied according to the time of day, an observation that they could not explain. Here we present work that explains this puzzle, demonstrating that the circadian clock regulates auxin signal transduction. Using genome-wide transcriptional profiling, we found many auxin-induced genes are under clock regulation. We verified that endogenous auxin signaling is clock regulated with a luciferase-based assay. Exogenous auxin has only modest effects on the plant clock, but the clock controls plant sensitivity to applied auxin. Notably, we found both transcriptional and growth responses to exogenous auxin are gated by the clock. Thus the circadian clock regulates some, and perhaps all, auxin responses. Consequently, many aspects of plant physiology not previously thought to be under circadian control may show time-of-day–specific sensitivity, with likely important consequences for plant growth and environmental responses. Most higher organisms, including plants and animals, have developed a time-keeping mechanism that allows them to anticipate daily fluctuations of environmental parameters such as light and temperature. This circadian clock efficiently coordinates plant growth and metabolism with respect to time of day by producing self-sustained rhythms of gene expression with an approximately 24-h period. One of the major contributors in specifying spatial patterns of plant growth and development is auxin, a hormone essential for nearly all stages of plant development. Auxin also helps the plant orient itself properly in response to environmental cues such as light, gravity, and water. We have now found circadian-regulated expression of components from nearly every step in the auxin-signaling pathway, from synthesis to response. We demonstrate the relevance of this observation by showing that plants have differential sensitivity to auxin at different times of day: the clock controls plant sensitivity to auxin at both the level of transcription and stem growth. Our work demonstrates an intimate connection between the clock- and auxin-signaling pathways, and suggests that other auxin-regulated processes may also be under circadian control. The circadian regulation of auxin responses suggests that many aspects of plant physiology not previously thought to be under circadian control may show time-of-day-specific sensitivity.
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影响因子：
56.9
作者：
Harmer, SL;Hogenesch, LB;Kay, SA
通讯作者：
Kay, SA
DOI：
10.1073/pnas.96.25.14652
发表时间：
1999-12-07
影响因子：
11.1
作者：
Bognár, LK;Hall, A;Millar, AJ
通讯作者：
Millar, AJ
影响因子：
7.4
作者：
Fowler, SG;Cook, D;Thomashow, ME
通讯作者：
Thomashow, ME
影响因子：
2.1
作者：
Hanano, Shigeru;Domagalska, Malgorzata A.;Davis, Seth J.
通讯作者：
Davis, Seth J.
影响因子：
9.4
作者：
HANSON, JB;TREWAVAS, AJ
通讯作者：
TREWAVAS, AJ