Thermomorphogenesis goes like clockwork: how the circadian clock fine-tunes temperature responses through competing transcriptional repressors

Like many other organisms, plants have an endogenous circadian clock that generates rhythmic outputs with c. 24-h periods, ensuring that developmental and physiological processes occur at an optimal time of day. At the core of the plant circadian clock is an intricate network of transcriptional activators and repressors arranged in interconnected feedback loops (Creux & Harmer, 2019). This central oscillator does not run in isolation but uses environmental signals such as light and temperature to adjust its phase. Simultaneously, the central oscillator gates processes such as growth and flowering in a light- and temperature-dependent manner. But despite advances made in recent years, our understanding of how the central oscillator perceives and relays temperature signals into output signalling pathways is still limited (for a recent review, see Gil & Park, 2019). In a recent article published in New Phytologist, Li et al. (2022; doi: 10.1111/nph.18442) reveal that competition between the two transcriptional repressors CIRCADIAN CLOCK ASSOCIATED 1 (CCA1) and REVEILLE 5 (RVE5), central components of the Arabidopsis circadian clock, helps tune gene expression at high ambient temperature.