Regulation of Temperature Stress Responses in Plants through Circadian Clock Genes

Plant growth and development are widely affected by ambient temperature conditions. Extreme temperatures cause widespread crop losses worldwide and severely limit the amount of land available for agricultural purposes. Thus, it is urgent to develop crops that are resistant to temperature stress along with other abiotic stresses. Plants memorize changes of temperature signals during a day along with day-length, creating circadian rhythms, which can timely control physiological, and metabolic processes. However, at the same time, they are insensitive to temperature changes and preserve circadian rhythms to maintain growth and survival(temperature compensation). As recent studies have reported that circadian clock genes control plant responses to temperature, attempts to acquire resistance to temperature stresses using circadian clock genes in crops are getting more attention. For example, The DEHYDRATION-RESPONSE ELEMENT-BINDING PROTEIN 1/C-REPEAT BINDING FACTOR (DREB1/CBFs) transcription factors are known as the master regulators in the transcriptional regulatory network for the acquisition of cold stress tolerance. In addition, plants adapt to high temperature stress through thermomorphogenesis, in which PHYTOCHROME INTERACTING FACTOR 4 (PIF4 ) transcriptional factor is involved. Even during the day, the expression of DREB1 and PIF4 varies over time, and plant responses to low and high temperatures show a diurnal cycle. Recent studies suggested that, the central oscillator genes CIRCADIAN CLOCK ASSOCIATED 1/LATE ELONGATED HYPOCOTYL (CCA1/LHY ) and PSEUDO-RESPONSE REGULATOR5/7/9 (PRR5/7/9) and the EVENING COMPLEX (EC ) genes REVEILLE4/REVEILLE8 (REV4/REV8) were involved in the DREB1 pathway of the cold signaling transcription factor, and the regulation of the thermomorphogenesis PIF4 gene. Another central oscillator, TIMING OF CAB EXPRESSION 1 (TOC1), and the regulatory protein ZEITLUPE (ZTL) were also revealed to be involved. In this review, we would like to introduce clock the circadian rhythm regulation and clock genes that are related to response to the temperature changes in plants, which will be used to establish strategies for plants to survive in the rapidly changing global climate.