Theoretical aspects of temperature effect on cyanobacterial circadian clock

Cyanobacteria exhibit circadian rhythms. Light is generally regarded as a synchronizer to the circadian clock, which can reset the phase of circadian rhythms. Meanwhile, temperature can also tune the progress of circadian rhythms in metazoans and plants. Some temperature responses of the cyanobacterial circadian clock have been observed, and their theoretical explanations are provided. This chapter describes the relationships between the clock and temperature from four points of view: The first is the so-called temperature compensation, which means that the period of circadian rhythms does not change as the temperature changes. Second, the focus is on how temperature cycles can entrain the cyanobacterial circadian clock. Third, a mathematical scenario for the nullification of the circadian clock at low temperatures based on experiments is provided. Fourth, the resonance of circadian rhythms with temperature cycles is described. Based on these observations, the evolutionary scenario of the cyanobacterial circadian clock is discussed.