ANALYTICAL ARGUMENT ON GOLDEN RICE - GENETICALLY ENGINEERED FOOD
Author: Ranjith. M
Tamil Nadu Agricultural University, Coimbatore- 641 003.
The idea for the Golden Rice project arose during an International conference in the Philippines in 1984 (Enserink, 2008). A team which included Ingo Potrykus from the Swiss Federal Institute of Technology in Zurich had succeeded in inducing genetically modified rice to generate carotenoids (Ye et al. 2000). The human body can use this provitamin A to synthesis essential vitamin A. Since grains of rice took on a yellow colour from the provitamin, this variety was quickly named Golden Rice. A cover story in Time Magazine in 2000 raised high expectations: "This rice could save a million kids a year." (Time Magazine 2000.) The article meant that this strain could theoretically be used to combat the vitamin A deficiency (VAD) that poses a problem in many developing countries. Children in particular, suffer serious health disorders if they don't receive enough food with carotenoids. Vitamin A deficiency can be life-threatening. The World Health Organization (WHO) estimates that some 250,000 to 500,000 children go blind every year, and that half of them die within 12 months (Enserink 2008).
A sample of rice grains was sent to Germany by the Golden Rice team in 2001 in order to test their technical quality in trials with mice. In particular, the tests were to find out how much provitamin A was absorbed in the intestines and how much of that could actually be utilised by the body. When rice grains were tested for their carotenoid content before the actual experiment began, scientists were surprised to learn that the rice contained less than one percent of the amount expected. After the rice was cooked, this share was reduced by another 50 percent1. As a result, the testing with mice was discontinued. If these findings, like so many other failures in research that have never been published, were to be verified, it would be certain that the quality of the rice at that time made it completely unsuitable for any real use.
QUESTIONS TO BE ANSWERED
How much carotene in rice degrades during storage?
No data has been published on this so far even though the Golden Rice Humanitarian Board confirms that there is a considerable need for clarity here. Officially, this was to be tested right after the first field trials in 2004: "Because of their chemical nature - several conjugated double bonds - carotenoids are susceptible to light and oxidation. The effects of light and air after harvest can be studied now that the first field trials have begun. From these studies it will be possible to make recommendations as to how and how long to store Golden Rice without losing its beneficial nutritive effects" (Humanitarian Board).
How much provitamin A remains after cooking?
Rice can be boiled, steamed or even fried in many different ways. One publication stated that a 10 percent loss could be expected during the cooking of genetically modified first-generation rice. (Datta, 2003). To date, there are still no data available on systematic trials with different cooking processes and how much carotenoid content is lost in each one.
How well can genetically modified rice be utilised by the body?
Another unknown is the conversion rate of genetically modified rice. The conversion rate (or bio-availability) provides information on how well carotenoids in rice can be absorbed and utilised by the human body. Estimates for GM rice fluctuate between 1:1 and 1:12. This question could be roughly answered by conducting feeding trials with animals, such as those trials originally planned at the German university which were discontinued. To date, nothing has been published on feeding tests
A fierce international controversy is raging over Golden Rice and other genetically modified varieties of rice. Following soy and maize, rice is now in the crosslines of gene technology. This is of supreme importance for developing countries. Although the commercial cultivation of insect-resistant rice has not been allowed in China, and in Europe the debate continues on approving the import of rice from the United States that is resistant to sprayed herbicides, GM rice has reached the European market - in 2006, GM rice both from the United States and China was found in Europe. While the rice from China had reached the market directly without approval from the authorities, the rice from the USA came from a cultivation experiment years earlier. Evidently the GM rice had been mixed in with seed production and had proliferated unnoticed for a longer period of time. In Germany alone, the trade suffered damages of some 10 million EURO because of this contamination with American rice, which the German government admitted when asked. It is evident that even small mistakes can quickly have consequences in global markets. The manufacturers of genetically modified seed lose control over their products far too quickly.
BT rice is modified to express the CRY IA(b) gene of the Bacillus thuringiensis bacterium. The gene confers resistance to a variety of pests including the rice borer through the production of endotoxins. The Chinese Government is currently doing trials on insect resistant cultivars. The benefit of this is that the farmers did not need to spray their crops to control fungal, viral, or bacterial pathogens. In comparison, conventional rice is sprayed three to four times per growing season to control pests. China has approved the rice for large scale use as of 2009. India, Indonesia, and Philippines are expected to carry out cultivation of genetically modified rice in the future.
Researchers in Japan are attempting to develop allergen free rice cultivars for people who are allergic to rice. Researchers are trying to repress the activity of the formation of allergen, AS-Albumin. Thus far the researchers have not been successful in completely eliminating the formation of AS-Albumin.
Also in Japan, lead researcher Fumio Takaiwa of Japan's National Institute for Agrobiological Sciences in Tsukuba tested a type of genetically modified rice on macaques (monkeys) that would prevent allergies to cedar pollen which causes hay fever. The symptoms a person can get to cedar pollen are itchy eyes, sneezing, and other serious allergic reactions. The modified rice contains seven proteins within cedar pollen to block these symptoms. When this was tested on the monkeys, the monkeys did not have any allergy symptoms to cedar pollen. More importantly, they did not have any side effects; Japanese scientists conclude that these types of rice are safe to use as an antihistamine to control cedar pollen allergy. Takaiwa is already doing clinical trials on patients to see if it works the same for humans. He states that if it works it, it will pave the way for genetically modified based vaccines and decrease the opposition toward genetically modified foods.
HUMAN BLOOD PROTEIN
Human serum albumin (HSA) is a blood protein in human plasma. It is used in treatment such as severe burns, liver cirrhosis, and hemorrhagic shock. More importantly, it is used in blood donations and thus is in short supply around the world. In China, the scientists modified brown rice as a cost effective way to produce HSA protein. The Chinese scientists put recombinant HSA protein promoters into 25 rice plants using Agrobacterium. Out of the 25 plants, nine of them breed (brown rice plants), and contained the HSA protein. They confirmed that the genetically modified brown rice had the same amino acid sequence as human serum albumin. They called this protein Oryza sativa recombinant HSA. The modified rice were transparent compared to regular rice. Additionally, they tested this protein on the rats with liver disease. The rats showed improved liver function.
As part of the C4 rice project scientists across the world are collaborating to try to produce a rice that uses C4 photosynthesis. C4 rice has the potential to produce 50% higher yields by turning sunlight into grain more efficiently. According to IRRI, "scientists have already identified crucial genes needed to assemble C4 photosynthesis in rice, and they now aim to produce C4 rice prototypes for testing".
GM rice has the following advantages,
• Increase effective yields and contribute to the fight against hunger and poverty
• Promote sustainable agriculture and help to reduce environmental degradation
• Have a positive impact on people's nutrition and health
• Strengthen the position of poor and small-scale farmers
Golden Rice Humanitarian Board, which steers communications and research around the vitamin A rice, admits that it will not solve all problems: "Golden Rice is not a replacement for existing efforts to tackle the problem, but could substantially complement them in the future and make them more sustainable, especially in remote rural areas."
2. Enserink, M. 2008. Tough Lessons from Golden Rice. In: Science, 230, 468-471.
3. Humanitarian Board. 10 October 2008. Quotes from the website: http://www.goldenrice.org.
4. Datta, K., N. Baisakh, N. Oliva, L. Torrizo, E. Abrigo, J. Tan, M. Rai, S. Rehana, S. Al-
Babili, P. Beyer, I. Potrykus, and S.K. Datta. 2003. Bioengineered 'golden' indica rice cultivars with Beta-carotene metabolism in the endosperm with hygromycin and mannose selection systems. In: Plant Biotechnology Journal, 1, 81-90.
5. Time Magazine. 31 July 2000. This rice could save a million kids a year. Vol. 156, No 5.
6. Ye, X., S. Al-Babili, A. Kloti, J. Zhang, P. Lucca, P. Beyer, and I. Potrykus. 2000. Engineering the provitamin A (Beta -carotene) biosynthetic pathway into (carotenoid-free) rice endosperm. In: Science, 287, 303-305.
About Author / Additional Info:
Am doing my Ph. D. in Agricultural Entomology at Tamil Nadu Agricultural University