Tajima, T., Oda, A., Nakagawa, M., Kamada, H. Background-dependent effects of polyglutamine variation in the Arabidopsis thaliana gene ELF3. ELF3-PIF4 interaction regulates plant growth independently of the Evening Complex. Nieto, C., López-Salmerón, V., Davière, J. Natural variants of ELF3 affect thermomorphogenesis by transcriptionally modulating PIF4-dependent auxin response genes. Ambient temperature signal feeds into the circadian clock transcriptional circuitry through the EC night-time repressor in Arabidopsis thaliana. ELF3 controls thermoresponsive growth in Arabidopsis. The evening complex coordinates environmental and endogenous signals in Arabidopsis. The ELF4–ELF3–LUX complex links the circadian clock to diurnal control of hypocotyl growth. The broad footprint of climate change from genes to biomes to people. The ability of temperature to rapidly shift ELF3 between active and inactive states via phase transition represents a previously unknown thermosensory mechanism. A purified fragment encompassing the ELF3 PrD reversibly forms liquid droplets in response to increasing temperatures in vitro, indicating that these properties reflect a direct biophysical response conferred by the PrD. In both Arabidopsis and a heterologous system, ELF3 fused with green fluorescent protein forms speckles within minutes in response to higher temperatures, in a PrD-dependent manner. The temperature sensitivity of ELF3 is also modulated by the levels of ELF4, indicating that ELF4 can stabilize the function of ELF3. We show that ELF3 proteins in plants from hotter climates, with no detectable PrD, are active at high temperatures, and lack thermal responsiveness. Here we find that the length of the polyQ repeat correlates with thermal responsiveness. ELF3 contains a polyglutamine (polyQ) repeat 8, 9, 10, embedded within a predicted prion domain (PrD). The evening complex consists of EARLY FLOWERING 3 (ELF3) 4, 7, a large scaffold protein and key component of temperature sensing ELF4, a small α-helical protein and LUX ARRYTHMO (LUX), a DNA-binding protein required to recruit the evening complex to transcriptional targets. The evening complex acts as a temperature-responsive transcriptional repressor, providing rhythmicity and temperature responsiveness to growth through unknown mechanisms 2, 4, 5, 6. The evening complex is a major signalling hub and a core component of the plant circadian clock 2, 3. However, the mechanisms by which plants sense temperature are not well understood.
Temperature controls plant growth and development, and climate change has already altered the phenology of wild plants and crops 1.
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