生物钟参与调控植物体几乎所有的新陈代谢和生长发育过程。光是自然环境条件下调控生物钟的主要因素。植物通过“输入途径”将外界环境中光信号的变化传递到生物钟“中央振荡器”来调节中央振荡器核心基因的表达，进而通过“输出途径”调节植物体内的各种节律性反应。拟南芥CCA1基因编码一个MYB转录因子，是生物钟中央振荡器的核心成员。然而，目前光信号调节CCA1 节律性表达的分子机理尚不清楚。本项目将聚焦研究两个关键的科学问题：1）远红光受体光敏色素A（phyA）介导的远红光信号是如何传导到中央振荡器调节CCA1的节律性表达；2）phyA信号传导途径如何与生物钟中央振荡器相互协调控制CCA1的节律性表达，使植物得以保持与外界环境的一致性。该项目研究成果将极大地促进我们对于植物生物钟分子调控机理的理解，并对作物育种和农业生产也有重要的指导意义。

Circadian clock regulates almost every aspect of metabolism and development in plants. Light is a major environmental factor regulating circadian clock. Plants use a series of photoreceptors to perceive the light signals and through the "input pathway", transduce the light signal to the "central oscillator" of the clock, to regulate the rhythmic expression of key components of the central oscillator, and through the "output pathway" to regulate various rhythmic responses. In Arabidopsis, CCA1 encodes a MYB-type transcription factor, which is a key component of the central oscillator. Nevertheless, the molecular mechanisms underlying light regulation of rhythmic CCA1 expression are largely unclear. The two major objectives of this project are: 1) To investigate the molecular mechanisms of phytochrome A (phyA) mediated far-red light signal regulation of rhythmic CCA1 expression; and 2) To investigate the molecular mechanisms coordinating phyA signaling pathway and the central oscillator in regulation of rhythmic CCA1 expression. The expected results will greatly enhance our understanding of the molecular mechanisms governing circadian clock in plants, and provide useful guidance for crop breeding and agriculture.