Ambient temperature signalling in plants

• Temperature influences many processes, including flowering, the circadian clock and growth.
• PIF4 controls many responses to warmer temperature.
• H2A.Z-nucleosomes control the ambient temperature transcriptome.

Plants are exposed to daily and seasonal fluctuations in temperature. Within the ‘ambient’ temperature range (about 12–27°C for Arabidopsis) temperature differences have large effects on plant growth and development, disease resistance pathways and the circadian clock without activating temperature stress pathways. It is this developmental sensing and response to non-stressful temperatures that will be covered in this review. Recent advances have revealed key players in mediating temperature signals. The bHLH transcription factor PHYTOCHROME INTERACTING FACTOR4 (PIF4) has been shown to be a hub for multiple responses to warmer temperature in Arabidopsis, including flowering and hypocotyl elongation. Changes in chromatin state are involved in transmitting temperature signals to the transcriptome. Determining the precise mechanisms of temperature perception represents an exciting goal for the field.