Comparative Molecular Biology in Photoperiodic Flowering Between the Short-Day Plant Rice and the Long-Day Plant Arabidopsis

Abstract

Flowering plants are largely categorized into short-day and long-day plants. In some species, no floral response to photoperiods is observed, which creates another group, day-neutral plants. In 1920, Garner and Allard reported that many flowering plants recognize the day-length to determine flowering-time and set seeds at appropriate seasons (see reviews by [Mouradov et al 2002], [Simpson and Dean 2002]). Recent studies in a short-day plant, rice, and a long-day plant, Ara- bidopsis thaliana, revealed that plants utilize an evolutionarily conserved flow- ering pathway to establish opposite photoperiodic responses (see reviews by [Izawa et al 2003], [Yanovsky and Kay 2003]). Here I summarize recent progress on molecular mechanisms of photoperiodic flowering to overlook genetic players at molecular levels to confer both short-day and long-day responses in photoperi- odic flowering.