Hormone recognition, binding and selectivity

The auxin receptor TIR1 and the related AFBs are expressed from insect cells and binding is explored in terms of kinetics (surface plasmon resonance, Biacore), thermodynamics (isothermal titration calorimetry, ITC) and structure. It is known that auxin completes a nascent substrate binding pocket as it binds to TIR1. The substrates are the Aux/IAA transcriptional regulators which, on binding, become ubiquitinated through the ubiquitin E3 ligase activity of TIR1. We are exploring how selectivity is conferred for different auxins and different Aux/IAAs, and how these two variables affect each other. We are building pharmacophoric maps of auxin receptors in order to inform rational design and selection of novel auxins and anti-auxins.

We are starting to examine auxin transport proteins with the same degree of molecular precision. We recently published a pharmacophoric map of the auxin uptake carrier AUX1, reviewed the biochemistry of AUX1, and presented a model of PIN2.

Biosensors

Biosensors, like receptor proteins, need to recognise analytes with appropriate sensitivity and selectivity. The group is developing hormone sensor domains in order to generate experimental plant hormone biosensors. This work includes the development of DNA aptamers as sensor elements (see project details below), enzyme-based electrochemical sensors and polymeric nanomaterials as vehicles for sensors.

E-noses in agriculture

Electronic devices for detecting volatiles have developed rapidly and small, portable and highly sensitive devices are available for a wide range of applications. Communication via volatiles is commonplace in nature and I am interested in applying e-noses as real-time sensors for biological responses for the benefit of agriculture. This work is in collaboration with Dr James CovingtonLink opens in a new window (School of Engineering, University of Warwick).

Nanoparticles and plants

We are discovering the rules governing how nanoparticles get into plant tissues and into plant cells. Our focus is on "soft" particles. These are carbon-based polymers which can be designed and made to specification, and which we link to a fluor allowing us to visualise uptake in living plants. There is interest in developing nanoparticles as vehicles for carrying e.g. crop protection agents, as aids to precision farming. There is also concern over plastic nanoparticles as pollution in the environment and their potential to damage plants. By finding characters which either promote or interfere with uptake into plants we will be able to make informed decisions on polymer nanoparticles in agriculture.

Developing national policy for "Growing British":

Working with Warwick Crop Centre and other national agencies I am interested in how we can promote horticulture in the UK as a vital food production sector.