Dr Jo Hepworth

Postdoctoral Scientist
Dean Lab
Cell and Developmental Biology

I’m a postdoctoral researcher in the group of Prof. Dame Caroline Dean at the John Innes Centre, working on the mechanism and evolution of temperature integration in the model plant Arabidopsis thaliana. I’m a plant geneticist with a passion for understanding how plants coordinate their growth with their environment. In Prof. Dame Caroline Dean’s group I’m working on an ERC-funded project called ‘MEXTIM’: Measurement of temperature exposure and integration over time.

Prof. Dean’s lab works on the genetic mechanisms underlying flowering time control, particularly at the key floral repressor FLOWERING LOCUS C (FLC). FLOWERING LOCUS C (FLC) is a major regulator of development in Arabidopsis thaliana, as its expression pattern determines the life history of the plant by controlling the timing of the transition to flowering. FLC expression must be repressed by experiencing prolonged cold before flowering can occur, in a process called vernalisation. Vernalisation is a highly studied process that in standardised experiments has shed light on the genes required for vernalisation. As a gatekeeper to reproduction, genetic variation at the FLC locus is also under strong selection and variants are known that generate different responses to temperature.

However, although vernalisation allows plants to synchronise flowering with the end of winter, how do plants identify “winter”? The study of FLC has mainly been carried out in constant temperature conditions in the laboratory.  In the field during autumn and winter temperatures can span twenty degrees daily, more than the difference between autumn and winter – how do plants manage to tell the difference?!  In the MEXTIM project we are exploiting the FLC system to determine how organisms can measure and integrate temperature information over months to accurately recognise the passing seasons in time to complete their life cycle. To do this, we have been combining both field and controlled-environment experiments on Arabidopsis thaliana natural variants and mutants to investigate the contribution of known pathways to temperature sensing, and how these pathways have been locally adapted. By working closely with Dr Rea Antoniou Kourounioti in Prof. Martin Howard’s group, we are developing models that can both inform us of the underlying mechanism of temperature sensing, and predict gene responses to different winters.

Recent Publications

Hepworth J., Antoniou-Kourounioti R. L., Bloomer R. H., Selga C., Berggren K., Cox D., Collier Harris B. R., Irwin J. A., Holm S., Säll T., Howard M., Dean C. (2018)

Absence of warmth permits epigenetic memory of winter in Arabidopsis.

Nature communications 9 p639

Publisher’s version: 10.1038/s41467-018-03065-7

Hepworth J., Dean C. (2015)

Flowering Locus C's Lessons: Conserved Chromatin Switches Underpinning Developmental Timing and Adaptation.

Plant Physiology 168 p1237-45

Publisher’s version: 10.1104/pp.15.00496

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