Genetically Engineered Rice with Enhanced Iron and Carotenoids

Micronutrient deficiency is one of the major nutritional problem in the population of developing countries. Rice, a staple food contains very low amount of minerals and vitamins in the consumable milled seeds. In mature rice seed, external aleurone layer and embryo accumulates maximum amount of minerals, which are removed during milling leaving behind very low nutrient content in the edible seeds. Therefore, to increase the nutritional components in consumable rice grains, biotechnological strategy have been employed. Rice ferritin gene (Osfer2) has been cloned and overexpressed in Pusa Sugandhi II under the control of the endosperm specific promoter OsglutelinA2. The resulting transgenic milled seeds of Pusa sugandhi II showed up to 7.8 fold of ferritin overexpression and 2.09 fold of iron increment. In addition, phytic acid functions as antinutrient by chelating divalent metals such as iron, zinc that reduces mineral nutrition in cereal grains. The biosynthesis of phytic acid involves a complex metabolic pathway where myo-inositol phosphate synthase (MIPS) and inositol phosphate kinase-1 (IPK1) play the vital role. Aleurone layer specific downregulation of phytic acid biosynthesis through RNAi mediated silencing of mips and ipk gene expression has been employed for indirect enrichment of mineral in transgenic rice seed endosperms. Moreover, it has been noted that the transgenic plants possess no significant differences in morphological as well as other agronomic characters with those of non-transgenic plants. For accumulation of carotenoids (pro-vitaminA) in rice endosperm, phytoene synthase (psy) gene cloned from rice variety has been used together with phytoene desaturase to transform rice variety where both the genes were driven by endosperm-specific glutalin promoter. We are aiming to develop low phytate, low lipoxygenase rice with enhanced iron, zinc and β-carotene enriched nutrition rice.