To synchronize flowering time with spring, many plants undergo vernalization, a floral-promotion process triggered by exposure to long-term winter cold. In Arabidopsis thaliana, this is achieved through cold-mediated epigenetic silencing of the floral repressor, FLOWERING LOCUS C (FLC). COOLAIR, a cold-induced antisense RNA transcribed from the FLC locus, has been proposed to facilitate FLC silencing. Here, we show that C-repeat (CRT)/dehydration-responsive elements (DREs) at the 3′-end of FLC and CRT/DRE-binding factors (CBFs) are required for cold-mediated expression of COOLAIR. CBFs bind to CRT/DREs at the 3′-end of FLC, both in vitro and in vivo, and CBF levels increase gradually during vernalization. Cold-induced COOLAIR expression is severely impaired in cbfs mutants in which all CBF genes are knocked-out. Conversely, CBF-overexpressing plants show increased COOLAIR levels even at warm temperatures. We show that COOLAIR is induced by CBFs during early stages of vernalization but COOLAIR levels decrease in later phases as FLC chromatin transitions to an inactive state to which CBFs can no longer bind. We also demonstrate that cbfs and FLCΔCOOLAIR mutants exhibit a normal vernalization response despite their inability to activate COOLAIR expression during cold, revealing that COOLAIR is not required for the vernalization process.
No new data have been generated for this manuscript. Previously published datasets used for this study are deposited in NCBI, under BioProject accession codes PRJNA416120 and PRJNA732005.
Genome-wide identification of CBFs targets in ArabidopsisNCBI BioProject, PRJNA732005.
- Ilha Lee
- Ilha Lee
- Yuehui He
- Yuehui He
- Ilha Lee
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
- Richard Amasino, University of Wisconsin Madison, United States
© 2023, Jeon et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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