tailieunhanh - Báo cáo khoa học: Regulation of output from the plant circadian clock

Plants, like many other organisms, have endogenous biological clocks that enable them to organize their physiological, metabolic and developmental processes so that they occur at optimal times. The best studied of these biolo-gical clocks are the circadian systems that regulate daily ( 24 h) rhythms. At the core of the circadian system in every organism are oscillators respon-sible for generating circadian rhythms. | IFEBS Journal REVIEW ARTICLE Regulation of output from the plant circadian clock Esther Yakir Dror Hilman Yael Harir and Rachel M. Green Department of Plant Sciences and the Environment Institute for Life Sciences Hebrew University Jerusalem Israel Keywords circadian Arabidopsis plant output pathway transcription oscillator hormone calcium Correspondence R. M. Green Department of Plant Sciences and the Environment Institute for Life Sciences Hebrew University Givat Ram Jerusalem 91904 Israel Fax 972 2 658 4425 Tel. 972 2 658 5391 E-mail rgreen@ Received 24 October 2006 accepted 23 November 2006 doi Plants like many other organisms have endogenous biological clocks that enable them to organize their physiological metabolic and developmental processes so that they occur at optimal times. The best studied of these biological clocks are the circadian systems that regulate daily 24 h rhythms. At the core of the circadian system in every organism are oscillators responsible for generating circadian rhythms. These oscillators can be entrained set by cues from the environment such as daily changes in light and temperature. Completing the circadian clock model are the output pathways that provide a link between the oscillator and the various biological processes whose rhythms it controls. Over the past few years there has been a tremendous increase in our understanding of the mechanisms of the oscillator and entrainment pathways in plants and many useful reviews on the subject. In this review we focus on the output pathways by which the oscillator regulates rhythmic plant processes. In the first part of the review we describe the role of the circadian system in regulation at all stages of a plant s development from germination and growth to reproductive development as well as in multiple cellular processes. Indeed the importance of a circadian clock for plants can be gauged by the fact that so many facets of plant development .