LNK1/2 mediate circadian-gated thermotolerance by regulating ROS homeostasis and activating HSFA8-dependent feedback...

The plant circadian clock synchronizes physiological processes with daily and seasonal environmental changes, ensuring homeostasis and enhancing adaptability. Heat stress has become one of the major factors limiting stable crop yields, but the mechanism by which the circadian clock gates thermotolerance is largely unknown. Here, we demonstrate that LNK1/2 play a predominant role in the circadian gating of thermotolerance, strictly dependent on their transcriptional coactivator activity. The MYB-like transcription factors RVE4/8, components of the LNK-associated daytime complex, contribute partially to this thermotolerance, whereas CCA1/LHY antagonize it. Mechanistically, LNK1/2 promote thermotolerance by regulating the metabolism of reactive oxygen species (ROS), thus promoting a moderate level of H₂O₂ accumulation that enhances heat resistance. HSFA8, whose transcriptional activation is highly dependent on LNK1/2, contributes to circadian stability through a feedback mechanism that fine-tunes temperature compensation. Together, these findings establish LNK1/2 as key regulators of circadian timing, ROS signaling, and HSFA8-dependent feedback that coordinate thermotolerance while preserving circadian homeostasis.