Abstracts now available online - Euro Fed Lipid

The Production and Accumulation of Very Long Chain
Polyunsaturated Fatty acids (VLC-PUFAs) in Arabidopsis thaliana.
Monica Venegas-Caleron, Richard Haslam, Olga Sayanova, and Johnathan Napier.
Crop Performance and Improvement, Rothamsted Research, Harpenden, AL5 2JQ, UK.
Humans are not capable of de novo synthesis of VLC-PUFA such as, eicosapentaenoic
acid (EPA) and docosahexaenoic acid (DHA). Therefore the human diet must contain
these essential fatty acids. In particular EPA and DHA derived from fish have been
shown to improve human health. In particular it is suggested that n-3 VLC-PUFAs may
reduce the risk of metabolic syndrome, a term used to describe a collection of
pathologies indicative of a progression towards heart disease, diabetes, stroke and
obesity, which constitutes an increasing public health problem in industrialised societies.
The ability to produce such fatty acids in plants, as an alternative to marine sources, is
therefore of considerable interest.
The efficient reconstitution of VLC-PUFA biosynthesis in transgenic plants has been
demonstrated. However, a “substrate dichotomy” between the two key enzyme activities
(desaturases and elongases) of PUFA biosynthesis currently prevents high level
accumulation of these fatty acids in transgenic plants. In order to investigate this
bottleneck, Arabidopsis transgenic lines of different backgrounds are being
characterised expressing conventional and alternative desaturation pathways for
arachidonic acid (AA) and EPA. In particular, we are examining the contribution of acylchannelling
enzymes such as PDAT and LPAAT to the distribution of substrates for
VLC-PUFA biosynthesis. This is being achieved by using Arabidopsis mutants with T-
DNA disruptions in target genes that encode such activities. This approach will provide
an insight into lipid biosynthesis and hopefully deliver transgenic plants accumulating
high levels of VLC-PUFAs.
Acknowledgements
This work was supported as part of the EU Frame Work VI LIPGENE project (FP6-
2002-FOOD-1-505944). Rothamsted Research receives grant aided support from the
BBSRC.
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