Circadian entrainment and gating in a natural plant population

Abstract Circadian clocks coordinate physiology, development and behaviour with cycles of day and night, which contributes to organismal fitness. For this to occur, the circadian clock must be aligned with the natural daily fluctuations in the environmental conditions. Here, we investigated under natural conditions the role of environmental cues in adjusting the circadian clock, and how this affects clock outputs. By combining novel field-based experimentation in a natural plant population with genome-wide analysis and machine-learning strategies for data interpretation, we inferred that temperature cues change circadian timing under natural conditions. We inferred that low temperature cues can shift circadian phase under naturally fluctuating conditions, and that there are seasonal changes in the effects of temperature upon circadian entrainment. We also identified extensive circadian modulation of temperature responses under field conditions. Therefore, plasticity of circadian timing under natural conditions allows flexible responses of both the clock and its outputs to environmental stimuli.