Integrating sugar and light signals
In plants, sugars are produced from photosynthesis in a light-dependent manner. Hexose sugars, such as glucose, are used directly in metabolism or converted into sucrose for long-distance transport, polysaccharides, such as starch, for storage or complex polymers for building cell walls. Almost all fixed carbon on Earth is derived from conversion of atmospheric CO2 into sugars by photosynthesis. Understanding how plant cells sense and respond to sugars in the
context of the daily environment is a fundamental question in biology with important implications for crop improvement.
One research interest of the lab is to decipher interactions between carbohydrate metabolism and light signalling. Recent research revealed a role for photosynthetically-derived sugars in setting the plant circadian clock, a biological time-keeping mechanism (Haydon et al., 2013). This work showed that daily rhythms of light-dependent accumulation of sugars feed into the circadian gene regulatory network. Research in the lab aims to investigate the contribution of photosynthetic sugar production for a wider range of gene networks in the context of light signalling pathways and the molecular mechanisms of how this impacts on plant physiology and development. We use forward genetics to identify novel mutants with altered transcriptional responses to changes in sugar availability, as well as high-throughput chemical genetic screens to identify novel small molecule modifiers.
We use high-throughput screens of luciferase reporters to identify genetic or chemical modifiers of transcriptional reporters.
Circadian clocks drive biological rhythms to allow organisms to anticipate daily and seasonal changes in environment associated with the rotation of the planet. The components and mechanisms of the circadian oscillator in Arabidopsis has been the focus of intense research for many years, leading to a well-refined working model. We are interested in how metabolism regulates the oscillator, which appears to occur through multiple, distinct pathways to affect both circadian period (Haydon et al. 2013) and amplitude (Haydon et al. 2017). By deepening our understanding of how rhythmic photosynthetic metabolism contributes to biological time-keeping in plants, we hope to contribute to the working model of the circadian oscillator.
Circadian rhythms in Arabidopsis seedlings using a firefly luciferase reporter
Tissue-specific transcriptional reporters
We are developing a versatile luminescent reporter system to define cell-type specific molecular phenotypes. We use
these tools, in combination with transcriptomics, to identify transcriptional signatures associated with changes in environmental conditions.
Photomorphogenic signalling from the cell wall
Research in the lab also investigates modes of signalling from the plant cell wall, a complex and dynamic structure comprised of a matrix of complex carbohydrate polymers and proteins. We have identified mutants with cell wall defects that activate light signalling pathways (Sinclair et al. 2017). We aim to understand the mechanism and physiological significance of these intriguing signalling pathways acting from the cell wall.
Research in the lab has been funded by the BBSRC and The Royal Society with additional support from the University of York and The University of Melbourne.