Sensitive to freezing6 integrates cellular and environmental inputs to the plant circadian clock
Sensitive to freezing6 integrates cellular and environmental inputs to the plant circadian clock
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DOI：
10.1104/pp.108.123901
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发表时间：
2008-09-01
期刊：
影响因子：
7.4
通讯作者：
McWatters, Harriet G.
中科院分区：
文献类型：
--
作者：
Knight, Heather;Thomson, Adrian J. W.;McWatters, Harriet G.
拟南芥（Arabidopsis thaliana）的对冷冻敏感的突变体6（sfr 6）在长日照下开花较晚，这是由于长日照下光周期开花途径中的组分表达减少所致。基因表达的微阵列分析表明，一个与生物钟相关的基序，晚上元件，在sfr 6植物中下调基因的启动子中过度表达。叶片运动节律的分析发现，sfr 6植物表现出蔗糖（Suc）依赖的长周期表型;与野生型拟南芥不同，在sfr 6植物中的时钟没有在Suc存在下的较短的节奏。Sfr 6植物对Suc的其他发育反应没有改变，这表明对Suc的不敏感性仅限于时钟。我们研究了24小时内sfr 6和Suc对时钟基因表达的影响。sfr 6突变导致生物钟成分CIRCADIAN CLOCK ASSOCIATED 1、GIGANTEA和TIMING OF CAB 1的表达减少。这些变化独立于Suc的补充而发生。野生型植物表现出小的增加时钟基因的表达在Suc的存在下，这种响应Suc减少在Sfr 6植物。这项研究表明，时钟基因表达水平和时间的大的变化可能对时钟输出的影响不大。此外，虽然Suc影响拟南芥时钟的周期和准确性，但它导致时钟基因表达的相对较小的变化。
The sensitive to freezing6 (sfr6) mutant of Arabidopsis (Arabidopsis thaliana) is late flowering in long days due to reduced expression of components in the photoperiodic flowering pathway in long-day photoperiods. Microarray analysis of gene expression showed that a circadian clock-associated motif, the evening element, was overrepresented in promoters of genes down-regulated in sfr6 plants. Analysis of leaf movement rhythms found sfr6 plants showed a sucrose (Suc)-dependent long period phenotype; unlike wild-type Arabidopsis, the clock in sfr6 plants did not have a shorter rhythm in the presence of Suc. Other developmental responses to Suc were unaltered in sfr6 plants, suggesting insensitivity to Suc is restricted to the clock. We investigated the effect of sfr6 and Suc upon clock gene expression over 24 h. The sfr6 mutation resulted in reduced expression of the clock components CIRCADIAN CLOCK ASSOCIATED1, GIGANTEA, and TIMING OF CAB1. These changes occurred independently of Suc supplementation. Wild-type plants showed small increases in clock gene expression in the presence of Suc; this response to Suc was reduced in sfr6 plants. This study shows that large changes in level and timing of clock gene expression may have little effect upon clock outputs. Moreover, although Suc influences the period and accuracy of the Arabidopsis clock, it results in relatively minor changes in clock gene expression.