Natural temperature fluctuations promote COOLAIR regulation of FLC

Zhao, Y., Zhu, P., Hepworth, J., Bloomer, R., Antoniou-Kourounioti, R. L. , Doughty, J., Heckmann, A., Xu, C., Yang, H. and Dean, C. (2021) Natural temperature fluctuations promote COOLAIR regulation of FLC. Genes and Development, 35(11-12), pp. 888-898. (doi: 10.1101/gad.348362.121) (PMID:33985972) (PMCID:PMC8168555)

Abstract

Plants monitor many aspects of their fluctuating environments to help align their development with seasons. Molecular understanding of how noisy temperature cues are registered has emerged from dissection of vernalization in Arabidopsis, which involves a multiphase cold-dependent silencing of the floral repressor locus FLOWERING LOCUS C (FLC). Cold-induced transcriptional silencing precedes a low probability PRC2 epigenetic switching mechanism. The epigenetic switch requires the absence of warm temperatures as well as long-term cold exposure. However, the natural temperature inputs into the earlier transcriptional silencing phase are less well understood. Here, through investigation of Arabidopsis accessions in natural and climatically distinct field sites, we show that the first seasonal frost strongly induces expression of COOLAIR, the antisense transcripts at FLC. Chamber experiments delivering a constant mean temperature with different fluctuations showed the freezing induction of COOLAIR correlates with stronger repression of FLC mRNA. Identification of a mutant that ectopically activates COOLAIR revealed how COOLAIR up-regulation can directly reduce FLC expression. Consistent with this, transgenes designed to knockout COOLAIR perturbed the early phase of FLC silencing. However, all transgenes designed to remove COOLAIR resulted in increased production of novel convergent FLC antisense transcripts. Our study reveals how natural temperature fluctuations promote COOLAIR regulation of FLC, with the first autumn frost acting as a key indicator of autumn/winter arrival.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Antoniou Kourounioti, Dr Rea Laila
• Authors: Zhao, Y., Zhu, P., Hepworth, J., Bloomer, R., Antoniou-Kourounioti, R. L., Doughty, J., Heckmann, A., Xu, C., Yang, H., and Dean, C.
• College/School: College of Medical Veterinary and Life Sciences > School of Molecular Biosciences
• Journal Name: Genes and Development
• Publisher: Cold Spring Harbor Laboratory Press
• ISSN: 0890-9369
• ISSN (Online): 1549-5477
• Published Online: 13 May 2021
• Copyright Holders: Copyright © 2021 Zhao et al.
• First Published: First published in Genes and Development 35(11-12): 888-898
• Publisher Policy: Reproduced under a Creative Commons License