Metabolic engineering in mint plants: increasing essential oil yield through genetic manipulation of biosynthetic pathways

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This studentship is an excellent opportunity to become part of an international Global Challenges Research Fundproject to enhance the yield of high-value essential oil compounds in Mentha (mint) plants in order to produce elitemint varieties for cultivation and commercial exploitation by local farming communities in rural Uganda. DifferentMentha species have been shown to preferentially accumulate particular oil components, with the terpenoidcompounds menthol and carvone being most abundant in peppermint (M. x piperita) and spearmint (M. spicata)respectively, and these are used extensively in a broad range of foodstuffs, beverages, cosmetics and medicinalproducts. Other essential oil compounds such as nepetalactone, the active ingredient in catnip, are produced in theclosely related Nepeta genus and research has shown that nepetalactone has good insect repellence qualities, makingit an excellent candidate for the developmental of low-cost mosquito repellents in order to reduce the incidence ofmalaria.The biosynthetic pathways for menthol, carvone and nepetalactone are well-understood, and this project will employplant metabolic engineering via genetic modification to enhance the yield of these compounds in the essential oils.Using advanced modular DNA assembly techniques such as the Golden Gate cloning system, key enzymes involved inthe biosynthesis of menthol, carvone or nepetalactone will be manipulated by overexpression or down-regulationusing RNA interference in order to optimise the production and accumulation of these compounds in transgenic plants.This will involve the creation of single and multi-gene constructs using different combinations of promoters,terminators and regulation mechanisms to identify the optimum combination of genetic modifications to maximise oilcompound yield. Oil composition will be analysed by GC-MS and lines producing optimum oil profiles will be selectedfor growth trials in Uganda.Transgenic lines sent to our partner organisations in Uganda will be cultivated and the oils extracted and sold directlyor used for the development of local food, beverage and cosmetic products. Through partnerships establishedbetween Cardiff and Makerere Universities and with our local business partner organisation CEMPOP, this project willensure that sustainable financial benefits accrue principally to local communities in Uganda, via cooperative groupsset up to grow, harvest and exploit new mint crops.The student will join a dynamic team of scientists working on the BBSRC GCRF-funded project and will be supervisedby a highly-experienced plant molecular biologist and a world-class biological chemist.