Illuminating the Arabidopsis circadian epigenome: Dynamics of histone acetylation and deacetylation

The circadian clock generates rhythms in biological processes including plant development and metabolism. Light synchro-nizes the circadian clock with the day and night cycle and also triggers developmental transitions such as germination, or flowering. The circadian and light signaling pathways are closely interconnected and understanding their mechanisms of action and regulation requires the integration of both pathways in their complexity. Here, we provide a glimpse into how chromatin remodeling lies at the interface of the circadian and light signaling regulation. We focus on histone acetylation/ deacetylation and the generation of permissive or repressive states for transcription. Several chromatin remodelers inter-vene in both pathways, suggesting that interaction with specific transcription factors might specify the proper timing or light -dependent responses. Deciphering the repertoire of chromatin remodelers and their interacting transcription factors will pro-vide a view on the circadian and light-dependent epigenetic landscape amenable for mechanistic studies and timely regu-lation of transcription in plants.

Automated summary

The circadian clock and light signaling pathways are closely interconnected, and chromatin remodeling plays a crucial role in regulating transcription timing and light-dependent responses.