Abstract

Signal transduction events that lead to circadian control of physiology are poorly understood. Cytosolic free calcium oscillates with circadian rhythm in plants and is postulated to be an output signal of the clock. A six months project has been conducted to complement a set of data already existing to show the importance of calcium in that processes, and the genes that might be under calcium regulation. We monitored Arabidopsis transcriptome using Affymetrix chips under an ectopic ramp of calcium. Calcium surprisingly changes the period of circadian regulated genes and affects some of the core clock components such as CCA1 /LHY and PRR3 and 9. Functional enrichment analysis revealed pleiotropic effect of the calcium treatment similar to salt treatments, inducing stress related gene expression. Our data also highlighted some potential candidates involved in calcium/clock signalling like Calmodulin like protein (CML) 23 and 24.