Proper timing of the flowering transition in plants is a key developmental process necessary for adaptation to various ecological niches. Many plant species require exposure to the prolonged cold of winter to flower, a temperature-sensing process referred to as vernalization. The cold memory is maintained mitotically and thus is an epigenetic switch that promotes flowering in spring. The cold-induced epigenetic switch is an important factor that affects the yield of various agricultural crops, because certain plants cannot flower at the proper time without vernalization. In Arabidopsis thaliana, prolonged exposure to cold epigenetically represses the expression of a floral repressor, FLOWERING LOCUS C (FLC). This is achieved by the increase of the evolutionary conserved Polycomb Repressive Complex2 (PRC2)-mediated epigenetic silencing mark, trimethylation of histone H3 at lysine 27 (H3K27me3), at FLC. However, how plants sense the prolonged cold and measure the duration of cold exposure are not known. Therefore, my research aims to identify and characterize the network of genes controlling a cold-induced epigenetic switch in plants.

Epigenetic regulation of plant-environment interactions