Targeted DNA methylation represses two enhancers of FLOWERING LOCUS T in Arabidopsis thaliana

FLOWERING LOCUS T ( FT ) plays a major role in regulating the floral transition in response to an inductive long day photoperiod in Arabidopsis thaliana . Expression of FT in leaves is dependent on the distal transcriptional enhancer Block C , located 5-kilobases (kb) upstream of the transcriptional start site (TSS). We expressed an inverted repeat of Block C to induce local DNA methylation and heterochromatin formation, which lead to FT downregulation in an inductive photoperiod. Using targeted DNA methylation as a tool to uncover further regulatory regions at the FT locus, we identified Block E , located 1 kb downstream of the gene, as a novel enhancer of FT . As Block C , Block E is conserved across Brassicaceae and located in accessible chromatin. Block C and E act as additive transcriptional enhancers that, in combination with the proximal FT promoter, control expression of FT in response to photoperiod in the leaf phloem.