Prof Giles JohnsonBSc, PhD


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Research interests

Exposure to environmental stresses, e.g. drought or low or high temperature, can have a damaging effect on plants, reducing the sucess of wild species and the productivity of crops. A common feature of most forms of abiotic stress is the production of reactive oxygen species, highly reactive molecules that can damage proteins, lipids and DNA. The aim of my research is to understand the pathways that lead to active oxygen production and how regulatory mechanisms can ameliorate that production. The particular emphasis is on the interaction between light and stress, and how light induces the production of reactive species.

In attempting to understand the mechanisms of regulation, we adopt a multi-disclipinary approach, combining state of the art spectroscopic and biochemical techniques with comparative studies in ecophysiology. We collaborate with colleages in Manchester and elsewhere in studies using metabolomics, proteomics and systems modelling.  Our research is focussing on the responses of plants to their environment on different time scales: 

In the short term, regulatory mechanisms eist that allow plants to control the capture of light and the flow of electrons to avoid production of reactive oxygen.  We were the firrst group to show evidence that plants operate a pathway of cyclic electron flow under steady state conditions.  This pathway is not widely excepted to be responsible to controlling the efficiency of light capture, through a process called non photochemical quenching.  At the same time, we have shown that the redox poise of the chloroplast plays an essential role in controlling electron transport.

Over longer timescales, plants are able to alter the composition of their cloroplasts to suit the prevailing conditions they experience.  We have identified a key transporter involved in signalling between the chloroplast and the nucleus and have shown that this signalling plays a major role in allowing plants to optimise their growth in natural environments, having a major impact on plant yields.

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Research and projects

No current projects are available for public display