2.3. RNA thermosensors
Temperature sensing through RNA structure has earlier been shown in bacteria and animals (Vu et al., 2019). Recently, an RNA based temperature ‘switch’ was also identified in plants. Chung et al.(2020) used ribosome profiling to identify genes that show an increase in translational efficiency at warm temperatures. Interestingly, one of the genes that showed enhanced translation was PIF7 . PIF7mRNA contains a hairpin structure in its 5’-UTR and the structure of this hairpin is temperature dependent (Fig. 2). It has been proposed that at low temperatures the hairpin forms and blocks PIF7 mRNA translation. At warm temperatures, the hairpin can no longer form and PIF7 can be translated (Chung et al., 2020; Fiorucci et al., 2020). As PIF7 is one of the key transcription factors regulating hypocotyl and petiole elongation at warm temperatures, the temperature-dependent folding of its mRNA can be considered a temperature sensor.