Más Paloma
Consorcio CSIC-IRTA, Laboratorio de Genética Molecular Vegetal, Instituto de Biología Molecular de Barcelona (IBMB-CSIC), Barcelona, Spain.
Int J Dev Biol. 2005;49(5-6):491-500. doi: 10.1387/ijdb.041968pm.
The daily rotation of the earth on its axis leads to predictable periodic fluctuations of environmental conditions. Accordingly, most organisms have evolved an internal timing mechanism, the circadian clock, which is able to recognize these 24-hour rhythmic oscillations. In plants, the temporal synchronization of physiology with the environment is essential for successful plant growth and development. The intimate connection between light signaling pathways and the circadian oscillator allows the anticipation of the environmental transitions and the measurement of day-length as an indicator of changing seasons. In recent years, significant advances have been made in the genetic and molecular dissection of the plant circadian system, mostly in Arabidopsis thaliana. The overall plant clock organization is highly complex; the system seems to include several input pathways, tightly regulated central oscillators and a myriad of outputs. The molecular cloning and characterization of a number of clock components has greatly improved our view of the plant central oscillator and additional players will most likely come into place very soon. Molecular mechanisms underlying circadian clock function are also beginning to be characterized. The emerging model relies on negative feedback loops at the core of the oscillator. Additional levels of post-transcriptional and post-translational regulation also contribute to the generation and maintenance of the rhythms. Globally, these studies have shed new light on how the clock coordinates plant physiology and development with the daily and seasonal environmental cycles.
地球每天绕轴自转导致环境条件出现可预测的周期性波动。因此，大多数生物进化出了一种内部计时机制——生物钟，它能够识别这些24小时的节律性振荡。在植物中，生理过程与环境的时间同步对于植物的成功生长和发育至关重要。光信号通路与生物钟振荡器之间的紧密联系使得植物能够预测环境变化，并将日长作为季节变化的指标进行测量。近年来，在植物生物钟系统的遗传和分子解析方面取得了重大进展，主要是在拟南芥中。植物生物钟的整体组织非常复杂；该系统似乎包括多个输入途径、受到严格调控的中央振荡器以及众多输出。一些生物钟组件的分子克隆和表征极大地改善了我们对植物中央振荡器的认识，而且很可能很快会有更多组件被发现。生物钟功能的分子机制也开始得到表征。新出现的模型依赖于振荡器核心的负反馈环。转录后和翻译后调控的其他层面也有助于节律的产生和维持。总体而言，这些研究为生物钟如何协调植物生理过程和发育与每日和季节性环境周期提供了新的见解。
