Mathematical models of circadian Ca2+ oscillations

In the model plant Arabidopsis thaliana, the concentration of cytosolic-free Ca2+ ([Ca2+]cyt) oscillates with a circadian rhythm. We are investigating the regulation and role of these oscillations both experimentally and mathematically. Through systems identification, we have developed simple mathematical models from a single experiment measuring [Ca2+]cyt and the promoter activity of CIRCADIAN CLOCK ASSOCIATED 1 (CCA1). Through validation with 4 contrasting datasets, including a clock-arrhythmic transgenic line (CCA1 overexpressor), we demonstrate the necessity for a light input pathway to regulate basal [Ca2+]cyt levels.