Four easy pieces: mechanisms underlying circadian regulation of growth and development

The circadian clock confers rhythms of approximately 24 hours to biological events. It elevates plant fitness by allowing plants to anticipate predictable environmental changes and organize life process to coincide with the most favorable environmental conditions. Many developmental events are circadian regulated to ensure that growth occurs at the ideal time or season relative to available resources. Circadian clock control over growth and development is often achieved through regulation of key phytohormone action. Circadian influence over the genome is widespread and the clock modulates genes involved in phytohormone synthesis and signaling, in addition to other pathways shaping growth and development. This review presents four nonmutually exclusive mechanisms by which temporal information is gleaned from the core oscillator and passed to pathways regulating plant growth and development.

Research highlights▶ Circadian clocks modulate phytohormone action to control growth and development. ▶ Circadian clocks directly regulate genes for phytohormone synthesis and signaling. ▶ Clock proteins interact with phytohormone regulators to influence growth events. ▶ Rhythmic transcription factors convey time cues to growth and development programs. ▶ An emergent mechanism for clock control of transcription is chromatin modification.