A Pair of Related Genes with Antagonistic Roles in Mediating Flowering Signals

Flowering in Arabidopsis is promoted via several interacting pathways. A photoperiod-dependent pathway relays signals from photoreceptors to a transcription factor gene, CONSTANS ( CO ), which activates downstream meristem identity genes such as LEAFY ( LFY ). FT , together with LFY , promotes flowering and is positively regulated by CO . Loss of FT causes delay in flowering, whereas overexpression of FT results in precocious flowering independent of CO or photoperiod. FT acts in part downstream of CO and mediates signals for flowering in an antagonistic manner with its homologous gene, TERMINAL FLOWER1 ( TFL1 ).