Distinct roles of CONSTANS target genes in reproductive development of Arabidopsis.

In plants, flowering is triggered by endogenous and environmental signals. CONSTANS (CO) promotes flowering of Arabidopsis in response to day length. Four early target genes of CO were identified using a steroid-inducible version of the protein. Two of these genes, SUPPRESSOR OF OVEREXPRESSION OF CO 1 (SOC1) and FLOWERING LOCUS T (FT), are required for CO to promote flowering; the others are involved in proline or ethylene biosynthesis. The SOC1 and FT genes are also regulated by a second flowering-time pathway that acts independently of CO. Thus, early target genes of CO define common components of distinct flowering-time pathways.