A morning-specific phytohormone gene expression program underlying rhythmic plant growth.
A morning-specific phytohormone gene expression program underlying rhythmic plant growth.
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DOI：
10.1371/journal.pbio.0060225
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发表时间：
2008-09-16
期刊：
影响因子：
9.8
通讯作者：
Chory, Joanne
中科院分区：
文献类型：
--
作者：
Michael, Todd P.;Breton, Ghislain;Hazen, Samuel P.;Priest, Henry;Mockler, Todd C.;Kay, Steve A.;Chory, Joanne
大多数生物体使用每日光/暗周期作为时间线索来控制许多基本的生理过程。在植物中，胚胎茎（下胚轴）的生长速率在一天中的不同时间最大，这取决于外部光周期和内部昼夜节律钟。然而，光信号，生物钟和生长促进激素途径在生长控制中的相互作用仍然知之甚少。在分子水平上，这种生长节律可以归因于几个不同的时间特异性控制层，如转录、信号或蛋白质丰度的定相。为了确定与生长节律控制相关的转录成分，我们应用了时间分析的拟南芥幼苗转录组在多种生长条件和突变体背景下使用DNA微阵列。我们发现，一组植物生长相关基因的共表达在一天的时间时，下胚轴的生长速度是最大的。这种表达与植物激素基因启动子中顺式作用元件（CACATG）的过度表达相关，这足以赋予体内预测的昼夜和昼夜表达模式。利用生物钟和光信号突变体，我们表明，内部一致的植物激素信号能力和外部一致的黑暗需要协调野生型的增长。从这些数据中，我们认为，生物钟间接控制光介导的植物激素转录水平，以一天中的适当时间的许可门控生长。激素途径的这种时间整合允许植物微调植物激素响应以进行季节性和适阴生长调节。植物的茎在黎明时伸长得更快。这种一天中特定时间的生长是由环境线索和生物钟的整合控制的。植物生长的特定效应物是植物激素：生长素、乙烯、赤霉素、脱落酸、油菜素类固醇和细胞分裂素。每一种植物激素在生长过程中既相互独立又相互重叠，了解植物激素之间的相互作用在过去的世纪一直是植物研究的重点。作者提出了一个模型，其中生物钟通过在黎明同步植物激素基因表达来协调生长，允许植物以特定条件的方式控制生长。此外，提出的结果提供了一个新的框架，为未来的实验，旨在了解的整合和串扰的植物激素。为什么植物在黎明时生长得更快？新的研究结果表明，光和生物钟通过在黎明时同步植物激素基因的表达来协调生长。
Most organisms use daily light/dark cycles as timing cues to control many essential physiological processes. In plants, growth rates of the embryonic stem (hypocotyl) are maximal at different times of day, depending on external photoperiod and the internal circadian clock. However, the interactions between light signaling, the circadian clock, and growth-promoting hormone pathways in growth control remain poorly understood. At the molecular level, such growth rhythms could be attributed to several different layers of time-specific control such as phasing of transcription, signaling, or protein abundance. To determine the transcriptional component associated with the rhythmic control of growth, we applied temporal analysis of the Arabidopsis thaliana seedling transcriptome under multiple growth conditions and mutant backgrounds using DNA microarrays. We show that a group of plant hormone-associated genes are coexpressed at the time of day when hypocotyl growth rate is maximal. This expression correlates with overrepresentation of a cis-acting element (CACATG) in phytohormone gene promoters, which is sufficient to confer the predicted diurnal and circadian expression patterns in vivo. Using circadian clock and light signaling mutants, we show that both internal coincidence of phytohormone signaling capacity and external coincidence with darkness are required to coordinate wild-type growth. From these data, we argue that the circadian clock indirectly controls growth by permissive gating of light-mediated phytohormone transcript levels to the proper time of day. This temporal integration of hormone pathways allows plants to fine tune phytohormone responses for seasonal and shade-appropriate growth regulation. In plants, stems elongate faster at dawn. This time-of-day–specific growth is controlled by integration of environmental cues and the circadian clock. The specific effectors of growth in plants are the phytohormones: auxin, ethylene, gibberellins, abscisic acid, brassinosteroids, and cytokinins. Each phytohormone plays an independent as well as an overlapping role in growth, and understanding the interactions of the phytohormones has dominated plant research over the past century. The authors present a model in which the circadian clock coordinates growth by synchronizing phytohormone gene expression at dawn, allowing a plant to control growth in a condition-specific manner. Furthermore, the results presented provide a new framework for future experiments aimed at understanding the integration and crosstalk of the phytohormones. Why do plants grow faster at dawn? New results suggest that light and the circadian clock coordinate growth by synchronizing the expression of plant hormone genes at dawn.
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影响因子：
7.2
作者：
Clough, SJ;Bent, AF
通讯作者：
Bent, AF
影响因子：
64.8
作者：
Doyle, MR;Davis, SJ;Amasino, RM
通讯作者：
Amasino, RM
影响因子：
16
作者：
Belden, William J.;Loros, Jennifer J.;Dunlap, Jay C.
通讯作者：
Dunlap, Jay C.
DOI：
10.1073/pnas.0404552101
发表时间：
2004-08-24
影响因子：
11.1
作者：
Mockler, TC;Yu, XH;Lin, CT
通讯作者：
Lin, CT
影响因子：
9.8
作者：
Covington MF;Harmer SL
通讯作者：
Harmer SL