circadian rhythms; photoperiod; systems identification; linear time invariant systems; external coincidence
Abstract :
[en] Circadian oscillators provide rhythmic temporal cues for a range of biological processes in plants and animals, enabling anticipation of the day/night cycle and enhancing fitness-associated traits. We have used engineering models to understand the control principles of a plant's response to seasonal variation. We show that the seasonal changes in the timing of circadian outputs require light regulation via feed-forward loops, combining rapid light-signaling pathways with entrained circadian oscillators. Linear time-invariant models of circadian rhythms were computed for 3,503 circadian-regulated genes and for the concentration of cytosolic-free calcium to quantify the magnitude and timing of regulation by circadian oscillators and light-signaling pathways. Bioinformatic and experimental analysis show that rapid light-induced regulation of circadian outputs is associated with seasonal rephasing of the output rhythm. We identify that external coincidence is required for rephasing of multiple output rhythms, and is therefore important in general phase control in addition to specific photoperiod-dependent processes such as flowering and hypocotyl elongation. Our findings uncover a fundamental design principle of circadian regulation, and identify the importance of rapid light-signaling pathways in temporal control.
Disciplines :
Engineering, computing & technology: Multidisciplinary, general & others
Author, co-author :
Dalchau, N.
Hubbard, K. E.
Robertson, F. C.
Hotta, C. T.
Briggs, H. M.
Stan, G. B.
Goncalves, Jorge ; University of Luxembourg > Luxembourg Centre for Systems Biomedicine (LCSB)
Webb, A. A.
Language :
English
Title :
Correct biological timing in Arabidopsis requires multiple light-signaling pathways.
Publication date :
2010
Journal title :
Proceedings of the National Academy of Sciences of the United States of America
ISSN :
1091-6490
Publisher :
National Academy of Sciences, Washington, United States - District of Columbia