主要发现：Here, we report that CBF 1, an AP 2/ERF ‐family transcription factor essential for plant cold acclimation, promotes hypocotyl growth under ambient temperatures in Arabidopsis.

结果：We show that CBF 1 increases the protein abundance of PIF 4 and PIF 5, two phytochrome‐interacting bHLH ‐family transcription factors that play pivotal roles in modulating plant growth and development, by directly binding to their promoters to induce their gene expression, and by inhibiting their interaction with phyB in the light. Moreover, our data demonstrate that CBF 1 promotes PIF 4/PIF 5 protein accumulation and hypocotyl growth at both 22°C and 17°C, but not at 4°C, with a more prominent role at 17°C than at 22°C.

结论：Together, our study reveals that CBF 1 integrates light and temperature control of hypocotyl growth by promoting PIF 4 and PIF 5 protein abundance in the light, thus providing insights into the integration mechanisms of light and temperature signaling pathways in plants.

CBF 1, a key regulator of plant cold acclimation, enhances Arabidopsis hypocotyl growth under ambient temperatures by promoting light‐dependent accumulation of phytochrome‐interacting transcription factors PIF 4 and PIF 5. CBF 1 thus integrates light and temperature control of hypocotyl growth in Arabidopsis.