Clock components, LHY and CCA1, control flowering through both a blue light receptor, FHA/CRY2, and a floral inducer, CO, in Arabidopsis

Abstract

In many organisms, a wide variety of biological processes are controlled by circadian rhythms. Two Myb-related genes, LHY and CCA1, have been shown to be closely associated with clock function in Arabidopsis. lhy cca1 double mutant plants flower much earlier than wild-type plants under SD and lose free-running rhythms in constant light. Loss-of-function of either a blue light receptor gene, FHA/CRY2 or a floral inducer gene, CO, causes late flowering and decreased expression of a floral activator gene, FT, under LD. To understand molecular mechanisms on photoperiodic control of flowering, we have tested genetic interactions among lhy, cca1, GI-ox, co, fha/cry2. Our results suggest that both FHA/CRY2 and CO mediate a circadian clock and a photoperiodic control of flowering in Arabidopsis.