University of Dundee

China Scholarship Council: Context is everything – how do plant receptor complexes assemble to regulate growth and immunity?

Supervisors: Dr Piers Hemsley, Prof Paul Birch (University of Dundee, Division of Plant Sciences and Prof Terry Smith (University of St Andrews)

Climate change is one of the biggest threats to global food production, leading to unpredictable weather patterns and geographical migration of pathogens. As sessile organisms, plants must respond to a changing environment in situ and have developed complex systems of perception and response to mitigate against environmental stress. Plants perceive physical environmental stimuli, such as pathogens, cell wall changes or hormones governing plant development, through receptor kinases in the plasma membrane. We have found that the correct assembly of activated receptor complexes is governed not only by protein-protein interactions but also by protein-lipid and lipid-lipid interactions. It is therefore necessary to understand the receptor protein complex in the context of its lipid environment. 

Using novel membrane solubilisation techniques to create membrane nanodiscs containing protein complexes and their attendant membrane lipids we have found that naïve receptors form ~300 kDa complexes, but upon ligand binding rapidly form complexes greater than 1 MDa. This is larger than any hypothesised receptor complex, suggesting that previous work has missed many crucial aspects of how these receptor complexes form and function. 

Using the antagonistic plant receptors FLS2 (bacterial immunity) and BRI1 (hormonal regulation of plant development) as test cases, you will define the proteome and lipidome of active and inactive complexes. Using genetic and molecular techniques you will then investigate novel protein components found in each complex for a role in either immunity or plant development. You will also manipulate the membrane lipid components found associated with the activated complex by genetic or chemical means to determine how they impact upon complex formation, stability or signalling efficiency. This knowledge will provide substantial understanding of how plants perceive and respond to their external environment and mitigate against environmental change. 

This project will provide training in molecular biology, protein biochemistry, affinity and size-exclusion chromatography, quantitative plant developmental and immunity biology, plant genetics, plant transformation and mass spectrometry proteomics and lipidomics. You will join a diverse and collaborative lab with opportunities for international conference attendance and a wide range of scientific and transferrable skills training. Recent ~£65 million investment in the Advanced Plant Growth Centre and International Barley Hub ensure that cutting edge plant growth facilities are available, in addition to the world leading biochemical, molecular, lipidomic and proteomic expertise and facilities at Dundee and St. Andrews. 

https://www.lifesci.dundee.ac.uk/people/piers-hemsley 

For further details and informal discussion prospective students are strongly encouraged to contact Dr Piers Hemsley (pahemsley@dundeee.ac.uk), Prof Paul Birch (pbirch@dundee.ac.uk) or Prof Terry Smith (tks1@st-andrews.ac.uk) before submitting an application.