Writing in the Proceedings of the National Academy of Sciences (PNAS), researchers led by Paul Christou from the Universitat de Lleida in Spain report they have genetically engineered corn to contain beta-carotene levels 169 times than normal levels, 6-fold the normal amount of vitamin C, and twice the normal amount of folate.
“The adoption of nutritionally improved corn will help to improve the health and well-being of the world’s poorest people, but this advancement will only be possible if political differences over the development and use of transgenic crops are set aside and their deployment and cultivation is regulated according to robust, science-based criteria,” wrote the researchers in PNAS.
A number of genetically modified plants and crops are coming to light with enhanced nutritional content considered to offer human health benefits, including flavonoid-rich tomatoes, zeaxanthin in potato tubers, and the omega-3 fatty acid, eicosapentaeoic acid (EPA), to soybeans, brassica, and stearidonic acid (SDA) in canola crops.
For the new corn, 10- to 14-day-old corn embryos were infused with five genes: Two genes to synthesise beta-carotene, one gene for folate, one for vitamin C, and one marker gene.
These genes were found to significantly enhance the levels of all three nutrients, compared to wild-type white corn, said the researchers.
Indeed, levels of beta-carotene, a pro-vitamin A nutrient, were five times higher than in the previously engineered Golden Rice, an enriched transgenic rice.
“There is no doubt that the nutritional qualities of plants can be enhanced by genetic engineering and that the results outstrip those achieved through conventional breeding,” wrote the researchers.
“Breeding is rarely an adequate solution on its own because of the characteristics of the plant species itself or the nutrient of interest.
“Therefore, the best biofortification strategies will likely involve genetic engineering in conjunction with conventional breeding, particularly when the direct enhancement of local elite breeding varieties is required,” they added.
The research is reportedly humanitarian in nature and is intended as a way of helping impoverished people in sub-Saharan Africa. Initial field trials of the crop will occur in the US next year, Dr Christou told the BBC.
GM not the cure
News of the development was met by resistance from campaign group Friends of the Earth. The BBC quotes the group’s Claire Oxborrow as saying that fortification of staples would not solve the malnourishment problem, but that people need better access to all foods.
"Supporting families to grow green leafy vegetables in their communities can ensure sufficient levels of vitamin A, as well as a host of other nutrients and vitamins that a narrow GM fix would not even begin to solve," Oxborrow told the BBC.
Dr Christou and his co-workers did address this issue in their article, noting: “In assessing strategies to deal with micronutrient deficiency, the provision of a varied diet with fresh fruit, vegetables, and fish would be ideal. However, where this varied diet is impossible because of poverty and poor governance, super-enhanced, nutritionally complete cereals could provide a durable solution to improve the health and general well-being of impoverished populations.”
Source: Proceedings of the National Academy of Sciences Published online PNAS Early Edition, doi: 10.1073/pnas.0901412106 “Transgenic multivitamin corn: Biofortification of corn endosperm with three vitamins representing three distinct metabolic pathways,” Authors: S. Naqvi, C. Zhu, G. Farre, K. Ramessar, L. Bassie, J. Breitenbach, D. Conesa, G. Ros, G. Sandmann, T. Capell, P. Christou