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Golden rice is a variety of rice (Oryza sativa) produced through genetic modification to biosynthesise of the precursors of beta-carotene (pro-vitamin A) in the edible parts of rice. The scientific details of the rice were first published in Science in 2000.^[1] Golden rice was developed as a fortified food to be used in areas where there is a shortage of dietary Vitamin A. In 2005, a new variety called golden rice 2 was announced, it produces up to 23 times more beta-carotene than the original variety of golden rice.^[2] Neither variety are available for human consumption.

Although golden rice was developed as a humanitarian tool it has met with significant opposition from environmental and anti-globalization activists.

Contents [hide] 1 Creation of golden rice 2 Golden rice and vitamin A deficiency 3 Golden rice and intellectual property issues 4 Objections 5 References 6 External links

 

Creation of golden rice

Golden rice was created by Ingo Potrykus of the Institute of Plant Sciences at the Swiss Federal Institute of Technology, working with Peter Beyer of the University of Freiburg. The project started in 1992. At the time of publication in 2000, Golden rice was considered a significant breakthrough in biotechnology as the researchers had engineered an entire biosynthetic pathway.

Golden rice was designed to produce Vitamin A precursor beta-carotene in the part of rice that people eat, the endosperm. The rice plant can produce beta-carotene, it is a carotenoid that occurs in the leaves and is involved in photosynthesis, however the plant does not normally produce the pigment in the endosperm since the endosperm is not a tissue where photosynthesis takes place.

Golden rice was created by transforming rice with three beta-carotene biosynthesis genes:

1. psy (photoene synthase)
2. lyc (lycopene cyclase) both from daffodil (Narcissus pseudonarcissus), and
3. crt1 from the soil bacterium Erwinia uredovora

The psy, lyc and crt1 genes were transformed into the nuclear genome and placed under the control of an endosperm specific promoter, so that they are only expressed in the endosperm. The lyc gene transfomed into the rice has a transit peptide sequence attached so that it is targeted to the plastid where geranylgeranyl-diphosphate formation occurs. It was important to use the bacterial gene crt1 since it can catalyze multiple steps in the synthesis of carotenoids, these steps require more than one enzyme in plants.^[3] The end product of the engineered pathway lycopene, if the plant accumulated lycopene the rice would be red. Recent analysis has shown that the plant endogenous enzymes process the lycopene to beta-carotene in the endosperm, giving the rice the distinctive yellow colour for which it is named.^[4] The original Golden rice was called SGR1, under greenhouse conditions it produced 1.6µg/g of carotenoids.

In 2005 a team of Reseachers at biotechnology company Syngenta produced a variety of golden rice called golden rice 2. They combined a photoene synthase gene from maize with the lyc and crt1 from the original golden rice. Golden rice 2, produces 23 times more carotenoids than golden rice (up to 37µg/g), and preferentially accumulates beta-carotene (up to 31µg/g of the 37µg/g of carotenoids). To meet recieve half the Recommended Dietary Allowance (RDA) it is estimated that 72 g of this rice would need to be eaten.

Golden rice has been bred with local rice cultivars in the Philippines, Taiwan and with the American rice variety Cocodrie, the first field trials of these golden rice cultivars were conducted by Louisiana State University AgCenter in 2004.^[5] Field testing will allow more accurate measurment of the nutritional value of golden rice and will enable feeding tests to be performed. Preliminary results from the field tests shown that field grown Golden rice produced 3 to 4 times more beta-carotene than the Golden rice grown under greenhouse conditions.^[6]

In June 2005, researcher Peter Beyer recieved funding from the Bill and Melinda Gates Foundation to further improve Golden rice by increasing levels of or bioavailability of pro-vitamin A, vitamin E, iron, and zinc, and improve protein quality though genetic modification.^[7]

 

Golden rice and vitamin A deficiency

The research that led to golden rice was conducted with the goal of helping the millions of children who suffer from Vitamin A deficiency (VAD). At the beginning of the 21st century, 124 million people were estimated to be affected by VAD, people are affected in 118 counrties in Africa and South East Asia. VAD is responsible for 1-2 million deaths, 500,000 cases of irreversible blindness and millions of cases of xerophthalmia annually.^[8] Children and pregnant women are at highest risk. Vitamin A is supplemented orally and by injection in areas where the diet is deficient in Vitamin A. As of 1999 there were 43 countries that had vitamin A supplementation programs for children under 5, in 10 of those countries 2 high dose supplements are available a year, which according to UNICEF could effectively elimiate VAD.^[9] However UNICEF and a number of NGOs involved in supplementation note that more frequent low-dose supplementation should be a goal where feasible.^[10]

Because many children in countries where there is a dietary deficiency in Vitamin A rely on rice as a staple food, the genetic modification to make rice produce provitamin A (beta-carotene) is seen a simple and less expensive alternative to vitamin supplements or an increase in the consumption of green vegetables or animal products. It is seen as the genetically engineered equivalent of fluoridated water or iodized salt.

Theoretical analyses of the potential nutritional benefits of golden rice show that consumption of golden rice would not eliminate the problems of blindness and increased mortality, but should be seen as a complement to other methods of Vitamin A supplementation^[11]. Golden rice and Golden rice 2 have not undergone nutritional testing.

 

Golden rice and intellectual property issues

Potrykus has spearheaded an effort to have golden rice distributed for free to subsistence farmers; this required several companies which had Intellectual Property rights to the results of Beyer's research to license it for free. Beyer had received funding from the European Commissions 'Carotene Plus' research program, by accepting those funds he was required by law to give the rights to his discovery to the corporate sponsors of that program, Zeneca, now Syngenta. Beyer and Poyrykus has used 70 Intellectual Property rights belonging to 32 different companies and universities in the making of golden rice, they needed to establish free licences for all of these so that Syngenta and humanitarian partners in the project could use golden rice in breeding programs and to develop new crops.^[12]

Free licences were granted quickly due to the positive publication that golden rice received; it was the first genetically modified crop that was inarguably beneficial, and thus met with widespread approval. Monsanto was one of the first companies to grant the group free licences.

The group also had to define the cutoff between humanitarian and commercial use, this figure was set at USD$10 000, therefore as long as a farmer or subsequent user of golden rice genetics does not make more than $10 000, then no royalties need to be paid to Syngenta for commercial use.

 

Objections

Greenpeace initially objected to the crop on the basis of the amount of Vitamin A in golden rice. The first strains developed had only 1.6 micrograms of beta-carotene per gram of rice, which would mean that a person would have to eat 1.5–2 kg of the rice per day to get the recommended daily allowance of provitamin A. However, with the development of lines with increased beta carotene Greenpeace has maintained its objection to the crop. Greenpeace opposes all genetically modified organisms, and is concerned that golden rice is a Trojan horse that will "open the door" to more widespread use of GMOs^[13].

Vandana Shiva, an Indian anti-GMO activist, argued that the problem was not particular deficiencies in the crops themselves, but problems with poverty and loss of biodiversity in food crops. These problems are aggravated by the corporate control of agriculture based on genetically modified foods. By focusing on a narrow problem (vitamin A deficiency), Shiva argued, the golden rice proponents were obscuring the larger issue of a lack of broad availability of diverse and nutritionally adequate sources of food.^[14] Similarly other groups have argued that a varied diet containing vitamin A rich foods like sweet potato, leafy green vegetables and fruit would provide children with sufficient vitamin A.^[15] While this is true, a varied diet is beyond the means of the many of the poor, which is why they subsist on a diet of rice.

The aleurone layer that surrounds the rice endosperm is removed by processing in most countries to improve the shelf life of the rice, this process is called milling or polishing. Brown rice with the aleurone intact does contain more B vitamins, iron, manganese, selenium, zinc and phosphorous than milled rice. The Institute of Science in Society claims that if rice weren't milled that supplementation would not be necessary.^[16] However USDA data shows that brown rice does not contain any more beta carotene than milled rice. ^{[17] [18]} Scientists at the International Rice Research Institute are screening rice germplasm, and trying conventional breeding approaches for breeding varieties with increased beta carotene in the aleurone. ^[19]

Many cultures base the quality of rice on its whiteness. In spite of the touted health benefits, due to the yellow coloring of golden rice, recipients may not be easily convinced it is healthier.

 

References

1. ^  Ye et al. 2000. Engineering the provitamin A (beta-carotene) biosynthetic pathway into (carotenoid-free) rice endosperm. Science 287 (5451): 303-305 PMID 10634784
2. ^  Paine et al. 2005. Improving the nutritional value of Golden Rice through increased pro-vitamin A content. Nature Biotechnology doi:10.1038/nbt1082
3. ^  Hirschberg, J. 2001. Carotenoid biosynthesis in flowering plants. Current Opinion in Plant Biology 4:210-218
4. ^  Schaub, P. et al. 2005. Why Is Golden Rice Golden (Yellow) Instead of Red?. Plant Physiology 138:441–450
5. ^  LSU AgCenter Communications. ‘Golden Rice’ Could Help Reduce Malnutrition, 2004
6. ^ Goldenrice.org [1]
7. ^ Grand Challenges in Global Health, Press release, June 27, 2005
8. ^  Humphrey, J.H., West, K.P. Jr, and Sommer, A. 1992. Vitamin A deficiency and attributable mortality in under-5-year-olds. WHO Bulletin 70: 225-232
9. ^  UNICEF. Vitamin A deficiency
10. ^  Vitamin A Global Initiative. 1997. A Strategy for Acceleration of Progress in Combating Vitamin A Deficiency
11. ^  Dawe, D., Robertson, R. and Unnevehr, L. 2002. Golden rice: what role could it play in alleviation of vitamin A deficiency? Food Policy 27:541-560
12. ^  Potrykus, I. 2001. Golden Rice and Beyond. Plant Physiology 125:1157-1161
13. ^  Greenpeace. 2005. All that Glitters is not Gold: The False Hope of Golden Rice
14. ^  Shiva, V. The Golden Rice Hoax
15. ^  Friends of the Earth. Golden Rice and Vitamin A Deficiency
16. ^  Institute of Science in Society. The 'Golden Rice' - An Exercise in How Not to Do Science
17. ^ USDA National Nutrient Database for Standard Reference. Rice, brown, long-grain, cooked
18. ^ USDA National Nutrient Database for Standard Reference. Rice, white, long-grain, regular, cooked
19. ^ International Rice Research Institute. 2005. Prgram 3, Annual Report of the Director General 2004-05