Crop Plants 'Green Factories' for Fish Oils21 November 2013
US - Omega-3 long chain polyunsaturated fatty acids (LC-PUFAs) have been shown to be beneficial for human health and the primary dietary sources of these fatty acids are marine fish either wild stocks or farmed fish (aquaculture).
The increasing demand for fish oils puts pressure on the natural marine resources and highlights the need to identify alternative sustainable sources of Omega-3 LC-PUFAs.
Rothamsted Research scientists, who receive strategic funding from the BBSRC, have successfully engineered the metabolic processes in the seed of false flax (Camelina sativa) to produce up to 12 per cent EPA and 14 per cent DHA. These amounts are very similar to those found in fish oil. The study is published in The Plant Journal.
The Omega-3 LC-PUFAs that are beneficial for health are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). They modulate both metabolic and immune processes and confer the health benefits in areas of Cardiovascular Heart Disease (CHD) and neurodevelopment. Plant sources of Omega-3, e.g. Flax seed, do not produce EPA and DHA; instead they produce shorter chain Omega-3 fatty acids such as a-linolenic acid (ALA).
ALA does not confer the health-beneficial properties associated with EPA and DHA, despite the former also being an Omega-3 fatty acid. The primary source for Omega-3 EPA and DHA are marine algae and diatoms and other photosynthetic organisms that comprise the phytoplankton. They are consumed by fish - and this is how fish accumulate these oils.
Dr Olga Sayanova, Rothamsted Research scientist funded by BBSRC said: "In this work we used as a starting point a plant that is rich in ALA which is the building block that is used to produce EPA and DHA Omega-3 oils.
Having identified in marine algae and other photosynthetic marine organisms the essential genes required to make these beneficial oils, we assembled them together and we introduced them to the Camelina plant. In the first instance, we introduced five genes and on average 24 per cent of the total oil content in the plant seed was EPA.
Then we introduced seven genes and in that case on average eight per cent of the total oil content in the seed of the plant was DHA and 11 per cent EPA. We had instances that these percentages were 14 per cent and 12 per cent respectively. The average accumulation of these oils in the transgenic Camelina plants is comparable to those found in fish oil but Camelina makes none of these naturally.
Professor Johnathan Napier, lead scientist of this project at Rothamsted Research said: "We are very excited with the results that we have achieved with this work. We have managed to generate a plant that can provide terrestrial sustainable sources of fish oils and this achievement can have potentially benefits for our health and the environment. Scientifically, it has been a great achievement as we had to understand really well the fundamental processes that underpin oil synthesis in seeds of plants in order to be able to reconstitute the synthesis of EPA and DHA in the seeds of Camelina."
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