Rational metabolic engineering of oilseed fatty acid composition

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Objective: To modify the oil composition of a target plant species in a predictable manner

There is continued interested in using vegetable oils for a range of different applications, including nutrition, industrial uses (e.g. lubricants) and more recently as biofuels (i.e. biodiesel). Considerable progress has been made over the last ten years in taking forward earlier biochemical models for plant lipid biosynthesis, predominantly through the use of genetic and metabolic engineering approaches. This has resulted in a framework model for the underlying biosynthetic routes for any given fatty acid, further underpinned by the molecular characterisation of the genes encoding the primary biosynthetic activities. However, a plethora of transgenic experiments indicate that our understanding of lipid synthesis and accumulation is at best partial, as witnessed by the relatively few examples of heterologous fatty acids accumulating to high levels in transgenic plants. For example, plants engineered to synthesis long chain polyunsaturated fatty acids such as those found in fish oils fail to efficiently accumulate these compounds, instead accumulating to high levels biosynthetic intermediates.

Therefore, the primary aim of this project is to identify (via biochemistry, reverse genetics and transgenesis) the endogenous factors which contribute to the channelling of fatty acids from their site of synthesis, through various stages of modification through to their ultimate site of deposition (triacyglcerols in seeds, but also membrane lipids). The identification of such factors (most likely to representing acyl-exchange enzymes) will allow the refining of our model of plant lipid synthesis and deposition and facilitate genetic interventions (GM or non-GM) to modify seed oil composition for any particular desired end-use.

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