These authors contributed equally to this work.
Resetting and regulation of FLOWERING LOCUS C expression during Arabidopsis reproductive development
Article first published online: 19 JAN 2009
© 2009 The Authors. Journal compilation © 2009 Blackwell Publishing Ltd
The Plant Journal
Volume 57, Issue 5, pages 918–931, March 2009
How to Cite
Choi, J., Hyun, Y., Kang, M.-J., In Yun, H., Yun, J.-Y., Lister, C., Dean, C., Amasino, R. M., Noh, B., Noh, Y.-S. and Choi, Y. (2009), Resetting and regulation of FLOWERING LOCUS C expression during Arabidopsis reproductive development. The Plant Journal, 57: 918–931. doi: 10.1111/j.1365-313X.2008.03776.x
- Issue published online: 19 FEB 2009
- Article first published online: 19 JAN 2009
- Received 10 November 2008; revised 26 November 2008; accepted 3 December 2008; published online 19 January 2009.
- FLOWERING LOCUS C;
- epigenetic resetting;
- FLC regulators
The epigenetic regulation of the floral repressor FLOWERING LOCUS C (FLC) is one of the critical factors that determine flowering time in Arabidopsis thaliana. Although many FLC regulators, and their effects on FLC chromatin, have been extensively studied, the epigenetic resetting of FLC has not yet been thoroughly characterized. Here, we investigate the FLC expression during gametogenesis and embryogenesis using FLC::GUS transgenic plants and RNA analysis. Regardless of the epigenetic state in adult plants, FLC expression disappeared in gametophytes. Subsequently, FLC expression was reactivated after fertilization in embryos, but not in the endosperm. Both parental alleles contributed equally to the expression of FLC in embryos. Surprisingly, the reactivation of FLC in early embryos was independent of FRIGIDA (FRI) and SUPPRESSOR OF FRIGIDA 4 (SUF4) activities. Instead, FRI, SUF4 and autonomous-pathway genes determined the level of FLC expression only in late embryogenesis. Many FLC regulators exhibited expression patterns similar to that of FLC, indicating potential roles in FLC reprogramming. An FVE mutation caused ectopic expression of FLC in the endosperm. A mutation in PHOTOPERIOD-INDEPENDENT EARLY FLOWERING 1 caused defects in FLC reactivation in early embryogenesis, and maintenance of full FLC expression in late embryogenesis. We also show that the polycomb group complex components, Fertilization-Independent endosperm and MEDEA, which mediate epigenetic regulation in seeds, are not relevant for FLC reprogramming. Based on our results, we propose that FLC reprogramming is composed of three phases: (i) repression in gametogenesis, (ii) reactivation in early embryogenesis and (iii) maintenance in late embryogenesis.