Genetically engineered rice containing larger amounts of nicotianamine to enhance the antihypertensive effect.

Nicotianamine (NA), a metal chelator ubiquitous in higher plants, serves as an antihypertensive substance in humans. To engineer a novel antihypertensive rice that contains larger amounts of NA, the barley NA synthase gene, HvNAS1, was introduced into rice via Agrobacterium-mediated transformation. The introduced HvNAS1 was driven by pGluB-1, which induces strong gene expression in the endosperm of rice seeds. The NA content in transgenic rice seeds was up to fourfold greater than that in non-transgenic rice seeds. The Cre/loxP DNA excision (CLX) system was used to remove the selectable marker gene for antibiotic resistance. Furthermore, the transgenic rice was crossed with a cleistogamous mutant to prevent gene transfer via pollen dispersal. These two modifications may minimize public concern with regard to the use of this transgenic rice.