SUMMARY : GOLDEN RICE
One of the applications of recombinant DNA technology in enriched foods field is golden rice. The organism used is daffodil or maize, bacteria Erwinia uredovora and Escherichia coli. The insertion of phytoene synthase (psy) gene from daffodil or maize and phytoene desaturase (crt I) from Erwinia uredovora into rice genome reintroduced carotenoid biosynthetic pathway in the endosperm that was absent before. This gives the ability of making β-carotene (precursor of Vitamin A) in the endosperm instead of vegetative tissue of rice plants. The phosphomannose isomerase (Pmi) gene from E. coli helps in positive selection of intended genes for producing golden rice . The recombinant DNA product is golden rice. The first generation of golden rice obtained by introducing foreign psy gene of daffodil and crt I gene of bacterium Erwinia uredovora into wild type rice strain genome. This produced 6 μg/g of carotenoids that correspond to1.6 μg/g of β-carotene . The successor GR2 is obtained by replacing psy gene from daffodil with similar gene from maize, produced total carotenoid up to two fold (maximum 37 μg/g) that correspond to 31 μg/g of β-carotene . Rather than spotting white colour as ordinary rice, golden rice is yellow dependent on the quantity of accumulated β-carotene inside grains which is absent in wild type rice strain . The application of this product is to provide adequate vitamin A according to recommended daily allowance (RDA) in rice-based developing countries that being plague with vitamin A deficiency (VAD) issue. Lack in daily supplementation of vitamin A weakened immune system of million infant and children, caused death while left thousands blind. The death rate for women during or shortly after pregnancy also suffered from VAD . The countries affected by VAD especially in Southeast Asia relied on rice as their basic staple. Thus supplementation of Vitamin A through rice is potentially effective when other source...
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