Re-engineering of amino acid metabolism and protein synthesis in wheat via CRISPR/Cas9 editing of the metabolic regulator, GCN2

We have produced wheat plants that accumulate very low levels of free (non-protein) asparagine in the grain, using CRISPR/Cas9 editing of asparagine synthetase genes. This is important because free asparagine is converted to a toxic contaminant, acrylamide, during everyday cooking and processing. The protein composition of these wheat plants differs from wild type, and this may affect how lines developed from them could be used if they were commercialised. We hypothesise that these changes involve GCN2, which is responsive to amino acid levels and is believed to be involved in the regulation not only of amino acid biosynthesis itself but also its crosstalk with diverse downstream systems, including plant/pathogen responses and defence priming. The student will test this hypothesis and investigate the roles of GCN2 more broadly by knocking out GCN2 in wild-type and low asparagine wheat.

 Rothamsted Research has developed an excellent platform for wheat transformation and genome editing. We have used this platform to produce plants with a range of knockout edits in asparagine synthetase genes. This led to Europe’s first genome edited wheat field trial, now in its 4th year, and subsequently to a project to enable farmers to grow and assess genome edited wheat lines, another European first. We are also using the platform to increase the lysine content of wheat grain. The student will work with the wheat transformation and editing team to design gRNAs to knock out GCN2 and perform the transformation required to introduce the gRNA and Cas9 genes into low asparagine and wild-type wheat backgrounds. Analysis of the edited plants will involve a range of techniques, including molecular biology, biochemistry, analytical techniques, such as HPLC, bioinformatics and analysis of next generation sequencing data, statistical analysis of complex datasets, and plant husbandry. It may even involve benchtop baking of biscuits and bread and the analysis of acrylamide levels. This will provide the student with excellent training for a career in molecular crop science related to a real-world food issue.  

The team has excellent links with other groups at Rothamsted and other institutions across Europe. We encourage and support our students in attending and presenting at conferences in the UK and abroad to start building a network of contacts. We also have links with plant breeders, farmers groups and international food businesses.  

Our aim as the SWBio DTP is to support students from a range of backgrounds and circumstances. Where needed, we will work with you to take into consideration reasonable project adaptations (for example to support caring responsibilities, disabilities, other significant personal circumstances) as well as flexible working and part-time study requests, to enable greater access to a PhD.  All our supervisors support us with this aim, so please feel comfortable in discussing further with the listed PhD project supervisor to see what is feasible.