is involved in the photoperiod- and sucrose-mediated control of flowering time in chrysanthemum.

The chrysanthemum genome harbors three genes: and are thought to act as regulators of floral induction under long-day (LD) and short-day (SD) conditions, respectively, whereas the function of is currently unclear. The objective of the present research was to explore the function of in the determination of flowering time of the photo-insensitive chrysanthemum cultivar 'Floral Yuuka', both in response to variation in the photoperiod and to the exogenous provision of sucrose. Spraying leaves of 'Floral Yuuka' plants with 50 mM sucrose accelerated flowering and increased the level of transcription in the leaf more strongly than either or under both long and SD conditions. Transcription profiling indicated that all three genes were upregulated during floral induction. The relationship of the sequence with that of other members of the family suggested that its product contributes to the florigen rather than to the anti-florigen complex. The heterologous expression of in the mutant rescued the mutant phenotype, showing that could compensate for the absence of . These results suggest that acts as a regulator of floral transition and responds to both the photoperiod and sucrose.