Rea has been working in the Professor Martin Howard and Professor Dame Caroline Dean groups to understand long-term temperature sensing in plants, and in particular how plants integrate the variable temperature signals they receive to distinguish between seasons.
From previous work scientists know that the vernalization machinery registers the experience of prolonged cold on the FLC locus through epigenetic marks.
Rea has developed a mathematical model of the vernalization pathway that simulates FLC expression and chromatin dynamics in response to different temperatures. The model was tested against quantitative experimental data of FLC and VIN3 RNA levels collected by Jo Hepworth and found to have strong predictive power.
The model also contributed to the mechanistic understanding of the process. It identified the steps of the pathway that are temperature-sensitive, finding the temperature signals that plants respond to most strongly and showed that almost every step in the pathway responds to temperature in some way, each at a different timescale.
Working with Yusheng Zhao, Rea investigated the slowest of the temperature input pathways, finding a new physical mechanism of temperature sensing. In this, the temperature-dependence of the growth rate is used to control the concentration of a stable protein through reduced dilution, leading to gradual accumulation in the cold. The concentration of this protein is thus a measure of the duration of the cold.
Rea also applied her modelling to understand epigenetic memory in a Swedish accession of Arabidopsis, working with Julia Questa and found a novel epigenetic state for long-term perpetuation of the silencing. The stability of this state was shown to depend on SNPs at the FLC locus.
From data analysis of the vernalization response of multiple accessions, Rea and Jo Hepworth found that the largest differences in their behaviour was due to different FLC starting levels, rather than the epigenetic response.
Rea is now working on a new project to understand the establishment of these initial FLC levels, which determine the degree of the vernalization requirement. This work is combining mathematical modelling with microscopy and molecular biology techniques and is part of the projects looking at ‘Epigenetic memory systems‘ and ‘Quantitative regulation of FLC expression‘.
Zhao Y,Antoniou-Kourounioti RL,Calder G,Dean C,Howard M (2020)Temperature-dependent growth contributes to long-term cold sensing.NaturePublisher's version: 0028-0836
Qüesta J. I., Antoniou-Kourounioti R., Rosa S., Li P., Duncan S., Whittaker C., Howard M., Dean C. (2020)Noncoding SNPs influence a distinct phase of Polycomb silencing to destabilize long-term epigenetic memory at Arabidopsis FLC.Genes & Development (34)Publisher's version: 0890-9369
Antoniou-Kourounioti R. L., Hepworth J., Heckmann A., Duncan S., Qüesta J., Rosa S., Säll T., Holm S., Dean C., Howard M. (2018)Temperature sensing is distributed throughout the regulatory network that controls FLC epigenetic silencing in vernalizationCell Systems (7)Publisher's version: 2405-4712