Arabidopsis EARLY FLOWERING 3 controls temperature responsiveness of the circadian clock independently of the evening complex

Abstract

Daily changes in light and temperature are major entrainment cues that enable the circadian clock to generate internal biological rhythms that are synchronized with the external environment. With the average global temperature predicted to keep increasing, the intricate light-temperature coordination that is necessary for clock functionality is expected to be seriously affected. Hence, understanding how temperature signals are perceived by the circadian clock has become an important issue. In Arabidopsis, the clock component EARLY FLOWERING 3 (ELF3) not only serves as a light Zeitnehmer, but also functions as a thermosensor participating in thermomorphogenesis. However, the role of ELF3 in temperature entrainment of the circadian clock is not fully understood. Here, we report that ELF3 is essential for delivering temperature input to the clock. We demonstrate that in the absence of ELF3, the oscillator is unable to respond to temperature changes, resulting in an impaired gating of thermoresponses. Consequently, clock-controlled physiological processes such as rhythmic growth and cotyledon movement were disturbed. Genetic analyses suggest that the evening complex is not required for ELF3-controlled thermoresponsiveness. Together, our results reveal that ELF3 is an essential Zeitnehmer for temperature sensing of the oscillator, and thereby for coordinating the rhythmic control of thermoresponsive physiological outputs.

Novel exotic alleles of EARLY FLOWERING 3 determine plant development in barley

“…AtELF3 also controls growth in response to ambient temperature and photoperiod (Anwer et al ., 2020; Box et al ., 2015; Jung et al ., 2020; Raschke et al ., 2015; Thines and Harmon, 2010; Zhu et al ., 2021). It was suggested to support crop improvement under higher temperature (Zhu et al ., 2021). For barley, Ejaz and von Korff (2017) could show that a non-functional elf3 leads to earlier flowering under high ambient temperature, whereas a functional ELF3 leads to later flowering.…”

“…ELF3, as a part of the circadian clock, might influence this as well in barley, as shown in Saade et al (2016), where ELF3 Hsp effects were increased under salinity stress (for HEA, TGW and HEI). AtELF3 also controls growth in response to ambient temperature and photoperiod (Anwer et al, 2020;Box et al, 2015;Jung et al, 2020;Raschke et al, 2015;Thines and Harmon, 2010;Zhu et al, 2021). It was suggested to support crop improvement under higher temperature (Zhu et al, 2021).…”

“…Together with ELF4 and LUX ARRYTHMO (LUX), AtELF3 forms the evening complex (EC), a transcriptional regulator, which is an integral part of the circadian clock, repressing clock and growth-associated transcription factors (Huang and Nusinow, 2016; Nusinow et al ., 2011). For loss-of-function AtELF3 mutants an early flowering phenotype was shown (Zagotta et al ., 1996) and in the context of this analysis it is important to note that AtELF3 controls photoperiod-responsive growth and flowering time, as well as temperature responsiveness of the circadian clock (Anwer et al ., 2020; Jung et al ., 2020; Zhu et al ., 2021).…”

The intersection between circadian and heat-responsive regulatory networks controls plant responses to increasing temperatures

“…ELF3's role in sensing ambient temperature changes extends beyond hypocotyl elongation. ELF3 also functions as a thermosensor in the temperature entertainment of the circadian clock [ 134 ].…”

An exotic allele of barley EARLY FLOWERING 3 contributes to developmental plasticity at elevated temperatures

“…The copyright holder for this preprint this version posted August 15, 2022. ; https://doi.org/10.1101/2022.08.15.503967 doi: bioRxiv preprint Zhu et al (2022) Barley ELF3 alleles tune phenotypic plasticity in response to high temperature based on studies in the model plant Arabidopsis thaliana. In Arabidopsis, changes in ambient temperature are perceived via multiple systems.…”