Abstract
In Arabidopsis thaliana, CONSTANS (CO) plays a central role in photoperiodic flowering through positively regulating the floral switch gene, FT. We first identified two cis-elements required for CO activation in the FT promoter by transient assays of Arabidopsis seedlings. We further identified a 10bp essential core consensus sequence as the true target of CO from the 21bp element II, one of the identified cis-elements, using its derivatives with scanning mutations. We next found several genes which have more than two consensus sequences in their promoters and exhibited distinct expression patterns between co mutant and the wild type in the public Arabidopsis microarray data. Finally, we next verified them as downstream genes of CO by transient analysis. The Hd1 gene, a rice ortholog of CO, can activate FT promoter in this transient assay. Therefore, we are now investigating on the cis-element recognition between CO and Hd1 in the transient analysis.
