Compositional analyses were performed on samples of rice grain, straw, and derived bran obtained from golden rice event GR2E and near-isogenic control PSBRc82 rice grown at four locations in the Philippines during 2015 and 2016. Grain samples were analyzed for key nutritional components, including proximates, fiber, polysaccharides, fatty acids, amino acids, minerals, vitamins, and antinutrients. Samples of straw and bran were analyzed for proximates and minerals. The only biologically meaningful difference between GR2E and control rice was in levels of β-carotene and other provitamin A carotenoids in the grain. Except for β-carotene and related carotenoids, the compositional parameters of GR2E rice were within the range of natural variability of those components in conventional rice varieties with a history of safe consumption. Mean provitamin A concentrations in milled rice of GR2E can contribute up to 89–113% and 57–99% of the estimated average requirement for vitamin A for preschool children in Bangladesh and the Philippines, respectively.

Golden Rice with β-carotene in the grain helps to address the problem of vitamin A deficiency. Prior to commercialize Golden Rice, several performance and regulatory checkpoints must be achieved. We report results of marker assisted backcross breeding of the GR2E trait into three popular rice varieties followed by a series of confined field tests of event GR2E introgression lines to assess their agronomic performance and carotenoid expression. Results from confined tests in the Philippines and Bangladesh have shown that GR2E introgression lines matched the performance of the recurrent parents for agronomic and yield performance, and the key components of grain quality. Moreover, no differences were observed in terms of pest and disease reaction. The best performing lines identified in each genetic background had significant amounts of carotenoids in the milled grains. These lines can supply 30–50% of the estimated average requirements of vitamin A.

part of the studies involved in safety assessment of genetically engineered crops includes characterizing the organization, integrity, and stability of the inserted DnA and evaluating the potential allergenicity and toxicity of newly-expressed proteins. Molecular characterization of the introduced DnA in provitamin A biofortified rice event GR2E confirmed insertion of a single copy of the transfer-DNA in the genome and its inheritance as a single locus. Nucleotide sequencing of the inserted DNA confirmed it was introduced without modifications. The phytoene synthase, and carotene desaturase proteins did not display sequence similarity with allergens or toxins. Both proteins were rapidly digested in simulated gastric fluid and their enzymatic activity was inhibited upon heat treatment. Acute oral toxicity testing of the protein in mice demonstrated lack of adverse effects. These evidences substantiated the lack of any identifiable hazards for both proteins and in combination with other existing comparative analyses provided assurance that food derived from this rice is safe. this conclusion is in line with those of the regulatory agencies of US food and Drug Administration, Health canada and food Standard Australia and new Zealand.Vitamin A deficiency (VAD) persists as a major public health nutrition problem, especially in sub-Saharan Africa and South Asia. Severe deficiency can lead to disorders such as xerophthalmia, the leading cause of preventable childhood blindness, anemia, and weakened host resistance to infection, which can increase the severity of infectious diseases and risk of death 1,2 . VAD increases vulnerability to a range of illnesses including diarrhea, measles, and respiratory infections, which are the leading causes of mortality among children in low and middle income countries, where risk of infection and risk of mortality can be compounded by coexisting under-nutrition. The prevalence and severity of xerophthalmia, anemia and the less-measurable "vicious cycle" between VAD and infection in vulnerable groups, notably young children and pregnant or lactating mothers, represent the most compelling consequences of VAD and underscore its significance as a public health problem around the world. In Bangladesh, the prevalence of VAD among preschool and school age children is a serious public health problem, with respective rates found to be 20.5 percent and 20.9 percent, respectively 3 .In Southeast Asian countries, the average per capita milled rice consumption is 130 kg/year or 360 g/day, providing nearly two-thirds of the necessary caloric intake. The high consumption of rice may reflect a lack of dietary diversity, which, when combined with the poor micronutrient content of polished rice in general and lack of any provitamin A, specifically, is a risk factor for VAD 4 . In addition to existing efforts, a complementary intervention for reducing VAD in the highest-risk countries is the biofortification of staple food crops with provitamin A. This approach has been successfully used with crops such ...

No abstract