The golden rice |
Vitamin A deficiency is the leading cause of blindness
in children in developing countries and contributes to high
mortality rates from illnesses such as measles, infectious
disease and diarrhoea. While this can easily be tackled
through better nutrition, many countries lack the infrastructure
or finance to do so with food supplements, an expensive,
and only short-term solution.
A FAIR project, aimed to tackle the problem of vitamin A
deficiency (VAD) by developing a genetically modified variety
of rice that can produce beta-carotene.
Vitamin A, a deadly deficiency
Vitamin A plays a crucial role in human health. It cannot be synthesised by humans who must obtain it through their diet, as preformed vitamin A (retinol) or pro-vitamin A (beta-carotene). Poor nutrition has led to vitamin A deficiency in 118 countries around the world with often fatal results. In the developed world, up to 2 mg of beta carotene are consumed per person/day, in the developing world this can be well below 0.5mg/day. The recommended daily allowance for vitamin A is 1 mg/d (equivalent to approx. 12 mg beta-carotene).
Children are particularly vulnerable and the World Health Organization (WHO) estimates that between 140-250 million pre-school age children worldwide are vitamin A deficient. They risk developing xerophthalmia – the primary cause of childhood blindness. In fact out of the 250,000 to 500,000 children who become irreversibly blind each year, 50% die within 12 months of becoming blind.
Vitamin A deficiency also makes children more susceptible to measles, HIV and other infectious diseases. Men experience reduced sperm count and women are at greater risk of stillbirth and are more likely to pass HIV/AIDS to their children .
Genetic technology transfer
Rice is the staple diet in many countries with a vitamin A problem. Ironically, grains often lose much nutritional value through milling, a process that prevents them becoming rancid in storage.
Through genetic and plant biotechnology developments in Europe, an opportunity arose to develop a rice variety containing high quantities of beta-carotene. This would allow people to absorb enough beta-carotene to synthesise the vitamin A that they lack.
The FAIR project ‘Carotene Plus’ met the challenge. The project originated from work carried out under Rockefeller Foundation funding and brought together experts in plant breeding, molecular genetics and nutrition from Italy (Ente per le Nuove Technologie L’Energia e l’ambiente), Netherlands (Advanta Netherlands), Germany (Albert Ludwigs Universität Freiburg In University Hohenheim Dept Biological Chemistry & Nutrition), France (CNRS Institut de Biologie Moleculaire), Switzerland (Swiss federal Institute of Technology), Spain (Universidad de Sevilla Dept de Genetica) and the UK (University of London Royal Holloway).
Striking gold
The overall objective of the project was to develop carotenoid-enriched plants, such as tomato or rice. The project succeeded in producing two of the three beta-carotene enriched, “golden” crops available worldwide (tomato and rice; the other one, canola, has been produced by Monsanto). In particular, a rice variety was produced that accumulates beta-carotene in its endosperm, the starchy part of the rice grain which is eaten. The research consisted of three phases:
- Phase I: Isolation of genes coding for the enzymes making up the beta-carotene synthesis pathway.
Four enzymes are essential for the synthesis of beta-carotene, phytoene synthase, phytoene desaturase, zeta carotene desaturase and lycopene cyclase.
- Phase II: Transformation of rice.
Rice (Oryza sativa) was transformed with the genes so that they expressed their enzymes in the rice endosperm, creating the building blocks for the synthesis of beta-carotene.
- Phase III: Analysis of transformed rice plants.
This is critical to ensure that the synthesis pathway is functioning and producing beta-carotene in the endosperm. It is also important to assess the quantity and bioavailability of beta-carotene being produced and how any aspect of plant growth may have been altered by the introduction of new genes.
The resulting grains are yellow, leading to the name 'Golden Rice'. The transformed plants grew healthily and the beta-carotene produced will be tested to check its bio-availability.
Successful transformation was a major advance in meeting WHO objectives of eradicating VAD through food fortification but further post-project work was needed both to assess stability of the genetically modified rice and to investigate how to increase the production of beta carotene to a level at which it would make a significant contribution to combating vitamin A deficiency.
From greenhouse to field
Future steps will ensure the successful introduction of Golden Rice into agricultural production and a number of initiatives are currently underway:
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Research to understand regulation of beta-carotene production in golden rice.
The amount of beta-carotene synthesised by the Golden Rice per 100g was not high enough to satisfy the Vitamin A RDA. Understanding how synthesis is regulated will allow scientists to ‘uprate’ production, creating rice grains that contain enough beta carotene to meet RDA requirements in manageable quantities.
-
Introduction of the beta carotene producing characteristics into local rice varieties.
Many types of rice are grown across the world from the familiar water-grown paddy rice to rice grown in dry fields. To be of practical use to farmers, rice suitable for different production systems must be developed, in collaboration with local breeders.
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Nutritional and safety testing.
This is essential as the genetically modified rice must be guaranteed stable and of nutritional benefit before it is released into agriculture.
-
Introduction into agriculture to combat vitamin A deficiency
This will be the fruition of all research and development carried out both during and after the project. It will launch a new phase of continuous monitoring by biologists, nutritionists and agronomists as they examine the impact of Golden Rice on people’s health and on agriculture in developing countries.
Expanding the partnership
In order to bring the regulatory, advisory and research expertise required
to make golden rice available in developing countries, the
technology was licensed to Syngenta AG, which granted a
free non-commercial license to the inventors with the right
to sub-license as part of the company’s commitment
to making Golden Rice freely available for humanitarian
purposes. The inventors granted sub-licenses to the International
Rice Research Institute (IRRI), the Philippine National
Rice Research Centre (PhilRice), the Indian Ministry of
Science, Technology and Human Resources, the Chinese Institute
of Genetics, Academica Sinica, Beijing; the Chinese National
Key Laboratory of Crop Genetic Improvement; and the Cuu
Long Delta Research Institute in Vietnam for further development.
This project has created an environment in which Golden
Rice can be used to address a simple but deadly nutritional
problem without altering agricultural practice or requiring
food supplements. It demonstrates that such projects rely
on bringing together genetic, nutritional, regulatory and
plant breeding expertise from both industrial and academic
fields on an international level to bring the work to a
successful conclusion.
Link:
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quality-of-life/wonderslife/project04_en.html
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