Overexpression of BBX18 Promotes Thermomorphogenesis Through the PRR5-PIF4 Pathway

Geonhee Hwang, Jeeyoon Park, Soohwan Kim, Jeonghyang Park, Dain Seo, Eunkyoo Oh

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


Thermomorphogenesis is the morphological response of plants to an elevation in the ambient temperature, which is mediated by the bHLH transcription factor PIF4. The evening-expressed clock component, PRR5, directly represses the expression of PIF4 mRNA. Additionally, PRR5 interacts with PIF4 protein and represses its transactivation activity, which in turn suppresses the thermoresponsive growth in the evening. Here, we found that the B-box zinc finger protein, BBX18, interacts with PRR5 through the B-Box2 domain. Deletion of the B-Box2 domain abolished the functions of BBX18, including the stimulation of PIF4 mRNA expression and hypocotyl growth. Overexpression of BBX18, and not of B-Box2-deleted BBX18, restored the expression of thermoresponsive genes in the evening. We further show that BBX18 prevents PRR5 from inhibiting PIF4-mediated high temperature responses. Taken together, our results suggest that BBX18 regulates thermoresponsive growth through the PRR5-PIF4 pathway.

Original languageEnglish
Article number782352
JournalFrontiers in Plant Science
Publication statusPublished - 2021 Nov 24

Bibliographical note

Funding Information:
This research was funded by the Basic Research Lab Program (2020R1A4A2002901) and the Basic Science Research Program (2019R1A2C1003783) of the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT, and a grant from Korea University.

Publisher Copyright:
Copyright © 2021 Hwang, Park, Kim, Park, Seo and Oh.


  • BBX18
  • PIF4
  • PRR5
  • high temperature
  • thermomorphogenesis

ASJC Scopus subject areas

  • Plant Science


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