Genetic and Epigenetic Understanding of the Seasonal Timing of Flowering

The developmental transition to flowering in many plants is timed by changing seasons, which enables plants to flower at a season that is favorable for seed production. Many plants grown at high latitudes perceive the seasonal cues of changing day length and/or winter cold (prolonged cold exposure), to regulate the expression of flowering-regulatory genes through the photoperiod pathway and/or vernalization pathway, and thus align flowering with a particular season. Recent studies in the model flowering plant Arabidopsis thaliana have revealed that diverse transcription factors engage various chromatin modifiers to regulate several key flowering-regulatory genes including FLOWERING LOCUS C (FLC) and FLOWERING LOCUS T (FT) in response to seasonal signals. Here, we summarize the current understanding of molecular and chromatin-regulatory or epigenetic mechanisms underlying the vernalization response and photoperiodic control of flowering in Arabidopsis. Moreover, the conservation and divergence of regulatory mechanisms for seasonal flowering in crops and other plants are briefly discussed.