Abstract
A variety of circadian rhythms have been observed in angiosperms. In contrast, only a very few examples have only been reported in relatively primitive plants: gymnosperms, ferns and bryophytes. We started the study of circadian rhythms and its molecular basis using the moss Physcomitrella patens, to which gene-targeting techniques are applicable. From P. patens, we have so far identified several clock-controlled genes (ccgs), all of which exhibited damping oscillation in continuous darkness while showing arrhythmic expression profiles in continuous light. The latter feature is contrasting to ccgs in angiosperms, which generally show rhythmic expression in continuous light. We show here results of recent analyses on some ccgs such as Lhcb genes and on moss homologs of Arabidopsis "clock gene" CCA1.
