Small molecules with hydantoin-containing and spiro-like structures promote devernalization in Arabidopsis

Abstract Monocarpic plants flower only once and then produce seeds. Many monocarpic plants require a cold treatment known as vernalization before they flower. This requirement delays flowering until the plant is exposed to warm temperatures in the spring. Exposure to high temperature following vernalization causes devernalization, which cancels the vernalized state, resulting in delayed flowering and the resumption of vegetative growth. In this study, we screened over 16,000 chemical compounds and identified five small molecules (devernalizers; DVRs) that induce devernalization at room temperature without requiring a high-temperature treatment. Treatment with DVRs reactivated the expression of FLOWERING LOCUS C (FLC), a master repressor of flowering, and delayed flowering time. Three of the DVRs share two structures: a hydantoin-like region and a spiro-like carbon. Treatment with DVR06, which has a simple chemical structure that includes these structures, delayed flowering time, and reduced the amount of repressive histone modification at FLC. Our extensive chemical screening revealed that hydantoin and spiro are key chemical signatures that reduce repressive histone modifications and promote devernalization in plants.