FAQs on Golden Rice Safety

Agronomically, GR2E Golden Rice is unchanged from conventional rice. The local cultivation practices currently followed for conventional rice varieties, including the application of fertilizer, crop protection products, and labor, are directly applicable to the cultivation of those varieties containing the GR2E nutritional trait. There will be no changes in either the type of production input, or in amounts, with the cultivation of GR2E Golden Rice varieties.

No changes in farm management or cultivation practices are anticipated should GR2E Golden Rice be adopted in agriculture in the future.

Since GR2E Golden Rice does not possess any introduced or altered resistance to insect pests or diseases, there are no selection pressures that could drive the evolution of resistant pest populations, and no anticipated changes in current pest control practices. Thus, there would be no requirement for the adoption of insect resistance management plans or other specific deployment strategies.

The incidence of rice diseases (e.g., bacterial leaf blight, leaf blast, sheath rot, and sheath blight) and damage from insect pests (e.g., rice bug, yellow stem borer) were recorded for GR2E Golden Rice and unmodified control rice grown at five locations during the 2017 boro season in Bangladesh. Based on these observations, there were no indications of altered disease susceptibility of GR2E rice compared to control rice, nor were there any indications that GR2E rice was a preferred host for pest insects.

Observations on the occurrence of pest and beneficial insect species were also recorded during confined field tests of GR2E rice in the Philippines. Overall, there were no indications that GR2E rice was a preferred host for pest insects or that there were any detrimental impacts on the prevalence of beneficial species.

Based on data from the aforementioned field tests, there were no indications that the genetic modification process resulting in GR2E Golden Rice had resulted in an unintended, unexpected, change in pest or disease susceptibility.

The introduced trait of provitamin A production in GR2E Golden Rice grains was not intended to alter a specific agronomic characteristic or to confer a fitness (selection) advantage to rice with respect to either abiotic or biotic stressors. Agronomic and phenotypic data collected from confined field tests of GR2E rice conducted at multiple locations in both Bangladesh and the Philippines have confirmed that the characteristics of rice with respect to seedling germination and vigour, plant growth and morphology, reproductive characteristics, and susceptibility to pests and diseases were not altered as an unintended, unexpected, consequence of the genetic modification process.

If the provitamin A trait is transferred by out-crossing from GR2E rice into other cultivated or weedy rice, progeny plants will not exhibit an altered selection advantage that could cause them to become more weedy or invasive in managed or unmanaged ecosystems. There are no anticipated adverse environmental consequences of introgression of the provitamin A trait from GR2E rice into other rice or sexually compatible species.

Rice is basically a self-pollinated crop, with limited degree of out-crossing (< 0.5 percent). The factors limiting the receptivity of rice flowers to out-crossing include a short style and stigma (1.5 to 4 mm in combined length), short anthers, limited pollen viability and brief period between opening of florets and release of pollen (between 30 seconds and 9 minutes). All wild and cultivated rice can also be wind-pollinated; however, rice pollen is short-lived with most pollen grains losing viability after approximately five minutes under typical environmental conditions.

Pollen viability is an important parameter that may affect gene flow frequencies at longer distances. As part of the characterization of GR2E Golden Rice to assess for potential unintended consequences of the genetic modification process, pollen morphology and viability were compared between GR2E and control rice. Morphologically, the appearance of pollen grains from GR2E and control rice was similar and there was no significant difference in pollen viability between samples obtained from GR2E and control rice. These data support the conclusion that pollen-mediated gene flow (out-crossing) from GR2E Golden Rice compared to conventional rice is unlikely to be changed as a result of altered pollen.

Germination and seedling growth parameters were compared between GR2E Golden Rice and control, non-transformed rice to investigate whether the genetic modification had resulted in unintended changes to the reproductive biology of rice that could affect environmental persistence or crop establishment. Germination tests conducted under two different temperature regimes did not reveal any significant differences in percent germination, total seedling length, or seedling vigour index.

The compositional evaluation of crops intentionally modified to express altered nutritional properties, such as GR2E Golden Rice, is intended to determine whether the composition differs significantly from its traditional counterpart aside from the intended change, and to assess the safety of the intended change and any unintended changes. Golden Rice is intended to produce provitamin A in the grains, unlike white rice, but otherwise its composition is intended to be equivalent to conventional rice.

The composition of key nutrients and anti-nutrients was determined in samples of GR2E rice grain (paddy), straw, and derived bran and compared to corresponding values from samples of conventional white rice. The choice of compositional parameters was based on the OECD consensus document on compositional considerations for new rice varieties, which for rice paddy included proximates, fibre, polysaccharides, fatty acids, amino acids, minerals, vitamins, and anti-nutrients. Straw and bran samples were analyzed for proximates and minerals.

The only biologically meaningful difference between GR2E Golden Rice and control rice was in levels of beta-carotene and other provitamin A carotenoids in the grain. Except for beta-carotene and related carotenoids, the compositional parameters measured in GR2E rice were within or similar to the range of natural variability of those components in conventional rice varieties with a history of safe consumption.

Other than the intended production of provitamin A in the grains, GR2E Golden Rice was found to be compositionally equivalent to conventional rice and there were no observed unintended, unexpected, changes in nutrient composition as a result of the genetic modification process.

As a macronutrient, protein is an essential component of the human diet and consumption of proteins as a class of dietary substances is not inherently associated with adverse effects. Of the thousands of proteins that may be ingested daily, only a very small number have the potential to exert anti-nutritional or toxic effects, or elicit allergic reaction in previously sensitized individuals.

Assessing the safety of newly-expressed proteins produced in the edible portions of a genetically engineered food crop is an integral component of the overall safety assessment. As there is currently no single criterion that is sufficiently predictive of potential toxicity or allergenicity, a “weight-of-evidence” approach is recommended for hazard identification that considers the history of use, amino acid sequence similarity to known toxins or allergens, function or mode of action, digestibility under standardized in vitro conditions, stability to heat or processing, and expression levels and potential dietary exposure.

GR2E Golden Rice contains three newly expressed proteins:

• ZmPSY1 – phytoene synthase from another food crop, maize, which catalyzes the condensations of two molecules of geranylgeranyl diphosphate to form 11-cis-phytoene, the first committed step in the carotenoid biosynthetic pathway;

• CRTI – phytoene desaturase from a common bacterial species (Pantoea ananatis), which catalyzes the conversion of 11-cis-phytoene to all-trans-lycopene, an immediate precursor of beta-carotene; and

• PMI – phosphomannose isomerase from the bacterium Escherichia coli, a normal inhabitant of the intestinal flora of humans and animals, which allows for positive selection of transformed plants on media containing mannose as the sole carbon source.

Each of the newly expressed proteins in GR2E rice was evaluated using the “weight-of-evidence” approach, and for each protein:

• bioinformatics studies confirmed the lack of any significant amino acid sequence similarity to proteins known to be toxic via oral exposure or to allergens;

• digestibility studies confirmed rapid degradation in the presence of simulated gastric fluid containing pepsin; and

• heat stability studies demonstrated rapid inactivation at temperatures below those used for cooking or processing.

In addition, mouse acute oral toxicity testing of the CRTI and PMI proteins showed a lack of toxic effects at dosages thousands of times more than any realistically conceivable dietary exposure from consuming GR2E rice. Taken together, the evidence indicates that neither ZmPSY1, CRTI, or PMI are likely to be toxic or result in allergic reactions in humans or animals. Conventional white rice is not considered a source of toxins or a significant source of anti-nutritional factors, nor is it considered by allergists to be a common allergenic food, and the genetic modification resulting in GR2E Golden Rice has not altered this safety profile.

The safety assessment of all foods derived from genetically engineered plants is based on the evaluation of these foods relative to their conventional counterparts that have a history of safe use. This concept has been described in international consensus documents, such as the Principles for the Risk Analysis of Foods Derived from Modern Biotechnology and the Guideline for the Conduct of Food Safety Assessment of Foods Derived from Recombinant-DNA Plants published by the Codex Alimentarius Commission.

In conducting the safety assessment of food/feed derived from GR2E Golden Rice, a number of criteria have been addressed including:

• characterisation of the transferred genes and their origin, function, and stability in the rice genome;

• characterization and concentrations of newly expressed proteins in the whole food;

• comprehensive nutrient compositional analyses of grain, straw, and derived bran;

• evaluation of intended and unintended changes; and

• the potential for any newly expressed proteins to be either allergic or toxic in humans or animals.

The purpose of these evaluations was to determine whether the use of GR2E Golden Rice in food, feed, or for processing, would raise any new safety concerns relative to conventional rice. The studies were not intended to address questions related to the efficacy of GR2E Golden Rice in helping to address vitamin A deficiency in affected population sub-groups, which can only be adequately addressed following regulatory authorization.

No potential public health and safety concerns were identified in the assessment of GR2E Golden Rice. Collectively, the data support the conclusion that food and/or livestock animal feed derived from provitamin A biofortified GR2E rice is as safe as food or feed derived from conventional rice varieties.