Abstract
Diverse organisms possess a circadian system that arrows them to coordinate physiological events with environmental day/night cycles.
In plants, a small family of genes, named ARABIDOPSIS PSEUDO RESPONSE REGULATORs (APRRs), are intriguing with special reference to circadian rhythms. To characterize these intriguing circadian-associated genes, we here employed an established Arabidopsis cell line (named T87). When T87 cells were grown in an appropriate light and dark (LD) cycle, cell autonomous diurnal oscillations of the APRR1/TOC1 quintet genes were observed at the level of transcription, as are in intact plants. After transferred to the conditions without any environmental time cues, particularly in constant dark (DD), we further showed that free-running circadian rhythms persisted in the cultured cells. This is the first indication of cell autonomous circadian rhythms in cultured cells in Arabidopsis thaliana, which will provide us with an alternative and advantageous means to characterize the plant biological clock.
