The LNK1 night light-inducible and clock-regulated gene is induced also in response to warm-night through the circadian clock nighttime repressor in Arabidopsis thaliana

Abstract

Ambient temperature has two fundamental impacts on the Arabidopsis circadian clock system in the processes referred to as temperature compensation and entrainment, respectively. These temperature-related longstanding problems have not yet been fully clarified. Recently, we provided evidence that temperature signals feed into the clock transcriptional circuitry through the evening complex (EC) nighttime repressor composed of LUX-ELF3-ELF4, and that the transcription of PRR9, PRR7, GI and LUX is commonly regulated through the nighttime repressor in response to both moderate changes in temperature (∆6 °C) and differences in steady-state growth-compatible temperature (16 °C to 28 °C). These temperature-associated characteristics of the core clock genes might be relevant to the fundamental oscillator functions. Here, we further show that the recently identified LNK1 night light-inducible and clock-controlled gene, which actually has a robust peak at daytime, is induced also by warm-night through the EC nighttime repressor in a manner very similar to PRR7, which is also night light-inducible daytime gene. Based on these findings, a hypothetical view is proposed with regard to the temperature entrainment of the central oscillator.

Keywords: :

• Arabidopsis thaliana
• circadian clock
• pseudo-response regulator
• temperature response
• transcription circuitry

Disclosure of Potential Conflicts of Interests

There were no potential conflicts of interests to disclose.

Acknowledgments

We would like to thank Dr. Onai and Dr. Ishiura (Nagoya University, Japan) for providing seeds of the pcl1–1 mutant, Dr. Millar (University of Edinburgh, UK) for the elf3–8 mutant and the ELF3:ELF3-YFP elf3–4 transgenic line, and also Dr. Kay (USC Dana and David Dornsife College of Letters, Arts and Sciences, CA) for the elf4–2 mutant and the LUX:LUX-GFP lux-4 transgeneic line. This work was supported by Japan Society for the Promotion of Science [no. 23580133 to T.Y., no. 24380046 to T.M.].