title: Regulatory principles and experimental approaches to the circadian control of starch turnover.
abstract: In many plants, starch is synthesized during the day and degraded during the night to avoid carbohydrate starvation in darkness. The circadian clock participates in a dynamic adjustment of starch turnover to changing environmental condition through unknown mechanisms. We used mathematical modelling to explore the possible scenarios for the control of starch turnover by the molecular components of the plant circadian clock. Several classes of plausible models were capable of describing the starch dynamics observed in a range of clock mutant plants and light conditions, including discriminating circadian protocols. Three example models of these classes are studied in detail, differing in several important ways. First, the clock components directly responsible for regulating starch degradation are different in each model. Second, the intermediate species in the pathway may play either an activating or inhibiting role on starch degradation. Third, the system may include a light-dependent interaction between the clock and downstream processes. Finally, the clock may be involved in the regulation of starch synthesis. We discuss the differences among the models' predictions for diel starch profiles and the properties of the circadian regulators. These suggest additional experiments to elucidate the pathway structure, avoid confounding results and identify the molecular components involved.
authors: SynthSys, University of Edinburgh, , C.H. Waddington Building, Mayfield Road, Edinburgh EH9 3JD, UK.
authors: Daniel D
authors: DD
authors: Seaton
authors: Oliver
authors: O
authors: Ebenhöh
authors: Andrew J
authors: AJ
authors: Millar
authors: Alexandra
authors: A
authors: Pokhilko
mesh_terms: D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism; D001683:Biological Clocks; D050260:Carbohydrate Metabolism; D002940:Circadian Rhythm; D003198:Computer Simulation; D025461:Feedback, Physiological; D018506:Gene Expression Regulation, Plant; D007700:Kinetics; D008027:Light; D008962:Models, Theoretical; D009154:Mutation; D017440:Photoperiod; D015398:Signal Transduction; D013213:Starch / Q000378:metabolism*; D049490:Systems Biology
chemical_list: D029681:Arabidopsis Proteins; D013213:Starch
keywords: Arabidopsis thaliana; biological clocks; circadian rhythms; mathematical modelling; starch metabolism; systems biology