CLOCK PIECES. “Up to now, over 20 components related to the circadian clock in Arabidopsis were identified, and homologous genes in other plants have been observed, indicating that this system is highly preserved in plants. The proteins that belong to the circadian clock act at different times during the night and the day, reciprocally regulating the expression of other genes, on the transcriptional and post transcriptional level.”
http://www.scielo.br/scielo.php?pid=S0100-83582016000100191&script=sci_arttext