Illuminating flowers: CONSTANS induces LEAFY expression.

Higher plants must undergo a major developmental switch, the transition to flowering, if they are to successfully complete their life cycle. In many plants, the crucial decision of when to begin to produce flowers is primarily controlled by environmental signals. The process of floral induction involves the integration of the activities of two types of genes: those that control flowering time as a response to the environment as well as an endogenous clock, and those that determine the floral identity of the cells. The first direct link between these two classes of genes has now been demonstrated. Forced expression of CONSTANS, a flowering-time gene, promotes flowering through the transcriptional activation of LEAFY, a flower-meristem-identity gene.