Plants use the plant hormone auxin to incorporate environmental cues into their growth and development to shape the final form. Temperature is an important modulator of all aspects of plant function and growth. In this work, we uncover temperature-regulated accumulation and solubility of members of the AUXIN RESPONSE FACTOR transcription factor family. We determine that ARF7 and ARF19 proteins rapidly hyperaccumulate in response to elevated temperature. Furthermore, we find that diffuse concentrations of ARF protein increase under elevated temperature, consistent with increased solubility. Temperature-driven ARF hyperaccumulation is not fully dependent on the well-established temperature response pathways. We find that natural variation in thermoregulated ARF accumulation is correlated with thermomorphogenesis, suggesting that this is a dial switch in plant temperature response. Regulated ARF thermoaccumulation provides a layer of complexity in shaping and plant growth and form, allowing plants to respond rapidly and persistently to elevated temperatures by modulating levels of nuclear ARF protein accumulation. Elevated temperature is shown to rapidly increase the abundance and solubility of key auxin regulators, ARF7 and ARF19. Natural variation in this thermoregulated accumulation correlates with plant growth responses, suggesting a tunable mechanism for temperature adaptation.
Wilkinson et al. (2026) studied this question.