Transcriptional Regulation of ELF4 Expression and Resetting of Circadian Clock by Light

昼夜节律是包括植物和动物在内的生物的生化、生理或行为过程中大约24小时的循环。生物钟在植物生物学中起着至关重要的作用，因此在农业中也是如此，因为生物钟控制的输出包括发芽时间、光合作用的昼夜优化和花的转换。每一种都被证明对植物的健康至关重要。昼夜节律可以通过昼夜循环来同步，因此植物可以正确地预测黎明和黄昏。尽管参与感知光信号的光感受器已经被很好地建立，但光信号是如何从光感受器传递到中央时钟的在很大程度上仍然是未知的。此外，关于中枢时钟基因的节律表达模式和循环输出响应(如植物的生长和光合作用活性)是如何产生和控制的，人们还知之甚少。本项目的目的是研究一组光和生物钟调控的转录因子(FHY3、FAR1、HY5、CCA1和LHY)在转录调控早花4(ELF4)基因表达和响应日光条件变化的生物钟重置中的作用。预计这项研究的结果将为生物钟调节的转录回路提供新的见解，并有助于更好地理解高等植物的生理和生殖。反过来，所获得的信息有可能用于未来在作物生长优化中的应用(如增加适合度、增加杂交活力和纬向生长限制)。该项目还将为在校儿童、本科生、研究生和博士后研究员提供极好的培训机会。

Circadian rhythm is a roughly 24-hour cycle in the biochemical, physiological, or behavioral processes of living entities, including both plants and animals. The circadian clock plays a crucial role in plant biology, and hence in agriculture, because outputs controlled by the clock include the timing of germination, diurnal optimization of photosynthesis, and floral transition. Each has been shown to be crucial for plant fitness. The circadian rhythms can be synchronized by the day/night cycle so that plants can correctly anticipate dawn and dusk. Although the photoreceptors involved in perceiving the light signals have been well established, how the light signals are transduced from the photoreceptors to the central clock remain largely unknown. In addition, little is known about how the rhythmic expression pattern of central clock genes and cyclic output responses (such as growth and photosynthetic activity of plants) are generated and controlled. The goal of this project is to investigate the role of a set of light- and circadian clock-regulated transcription factors (FHY3, FAR1, HY5, CCA1 and LHY) in transcriptional regulation of EARLY FLOWERING 4 (ELF4, a central clock component) gene expression and resetting of the circadian clock in response to changes in daily light conditions. It is expected that results from this study will provide fresh insights into the transcriptional circuitry underlying circadian clock regulation and lead to a better understanding of the physiology and reproduction in higher plants. In turn, the obtained information has the potential to be used for future application in optimizing growth of crop plants (such as increased fitness, increased hybrid vigor and latitudinal growth limit). This project will also provide excellent training opportunities for school children, undergraduate, graduate students and postdoc fellows.