Improving the nutritional value of Golden Rice through increased pro-vitamin A content

Abstract

'Golden Rice' is a variety of rice engineered to produce β-carotene (pro-vitamin A) to help combat vitamin A deficiency¹, and it has been predicted that its contribution to alleviating vitamin A deficiency would be substantially improved through even higher β-carotene content². We hypothesized that the daffodil gene encoding phytoene synthase (psy), one of the two genes used to develop Golden Rice, was the limiting step in β-carotene accumulation. Through systematic testing of other plant psys, we identified a psy from maize that substantially increased carotenoid accumulation in a model plant system. We went on to develop 'Golden Rice 2' introducing this psy in combination with the Erwinia uredovora carotene desaturase (crtI) used to generate the original Golden Rice¹. We observed an increase in total carotenoids of up to 23-fold (maximum 37 μg/g) compared to the original Golden Rice and a preferential accumulation of β-carotene.