Insight into a Physiological Role for the EC Night-Time Repressor in the XXXX Circadian Clock.

@entity59376 @entity958 @entity66262 @entity14979 @entity71159 @entity66261
Life cycle adaptation to seasonal variation in photoperiod and temperature is a major determinant of ecological success of widespread domestication of @entity958 . The circadian clock plays a role in the underlying mechanism for adaptation. Nevertheless, the mechanism by which the circadian clock tracks seasonal changes in photoperiod and temperature is a longstanding subject of research in the field. We previously showed that a set of the target genes (i.e. GI, LNK1. @entity66262 and @entity66261 ) of the Evening Complex (EC) consisting of LUX- @entity59376 - @entity71159 is synergistically induced in response to both warm-night and night-light signals. Here, we further show that the responses occur within a wide range of growth-compatible temperatures (16-28  C) in response to a small change in temperature (/\4  C). A dim light pulse (<1   mol m(-2) s(-1)) causes the enhanced effect on the transcription of EC targets. The night-light pulse antagonizes against a positive effect of the cool-night signal on the EC activity. The mechanism of double-checking external temperature and light signals through the EC nighttime repressor might enable plants to ignore (or tolerate) daily fluctuation of ambient temperature within a short time interval in their natural habitats. Taken together, the EC night-time repressor might play a physiological role in tracking seasonal variation in photoperiod and temperature by conservatively double-checking both the light and temperature conditions. Another EC target output gene @entity14979 regulating plant morphologies is also regulated by both the temperature and light stimuli during the night. Hence, the EC night-time repressor is also implicated in a physiological output of the @entity14979 -mediated regulation of morphologies in response to seasonal variation in photoperiod and ambient temperature.
