What is golden rice?
Golden rice
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Golden rice is the result
of an effort to develop rice varieties that produce
provitamin-A (beta-carotene) as a means of alleviating
vitamin A (retinol) deficiencies in the diets of poor
and disadvantaged people in developing countries. Because
traditional rice varieties do not produce provitamin-A,
transgenic technologies were required. |
| Through the work of two European scientists,
Dr. Ingo Potrykus of the Swiss Federal Institute of
Technology in Zurich and Dr. Peter Beyer of the University
of Freiburg in Germany, rice plants were developed containing
two daffodil genes and one bacterial gene that carry
out the four steps required for the production of beta-carotene
in rice endosperm. Endosperm is the nutritive tissue
surrounding the embryo of a seed and makes up the majority
of the rice grain that we eat. The resulting plants
appear normal except that after milling (to remove the
brown bran), their grain is a golden yellow color due
to the presence of provitamin-A (Toenniessen
2000). |
Source: Morten Lillemo,
Agricultural University of Norway
|
How does golden rice produce provitamin-A?
Provitamin-A is not produced by traditional rice varieties.
However, geranylgeranyl diphosphate (GGDP), a compound naturally
present in immature rice endosperm, with the help of several
enzymes not normally found in rice can be used to produce
provitamin-A (Ye
et al. 2000).
Daffodils
Source: www.turtlebackinn.com
|
Two genes from daffodil and
one from the bacterium Erwinia uredovora were inserted
in the rice genome. These three genes produce the enzymes
necessary to convert GGDP to provitamin-A. The inserted
genes are controlled by specific promoters such that
the enzymes and the provitamin-A are only produced in
the rice endosperm (Toenniessen
2000). |
When golden rice is ingested, the human body splits the
provitamin-A to make vitamin A. For a more detailed explanation
of the production of provitamin-A by golden rice, click
here.
Why is vitamin A important?
According to the World Health Organization (WHO), vitamin
A deficiency (VAD) is the leading cause of preventable blindness
in children. For children, a lack of vitamin A causes severe
visual impairments and blindness and significantly increases
the risk of severe illness, and even death, from common
infections such as diarrhea and measles. Pregnant mothers
are also affected by VAD. VAD in pregnant women causes night-blindness
and may also be associated with higher mother-to-child HIV
transmission rates as well as increased risk of maternal
mortality. WHO estimates between 100 and 140 million children
are vitamin A deficient. An estimated 250,000 to 500,000
children with VAD become blind every year and half of those
children die within a year of losing their sight (World
Health Organization 2002).
How much vitamin A will golden rice deliver?
One of the major arguments from opponents of golden rice
is that it will not provide enough vitamin A to benefit
those who are deficient. A statement from the organization
Greenpeace "Genetically
Engineered 'Golden Rice' is Fool's Gold", calculated
that an adult would have to eat 3.7 kilos (8 pounds) of
dry weight golden rice, approximately 9 kilos (20 pounds)
of cooked rice, to meet the daily need of vitamin A from
golden rice. A breast-feeding woman would have to eat at
least 6.3 kilos (14 pounds) dry weight or nearly 18 kilos
(40 pounds) of cooked golden rice per day. Based on these
calculations, Greenpeace estimated a normal daily intake
of 300 grams (0.7 pounds) of golden rice would at best provide
8% of the vitamin A needed daily. In response to the Greenpeace
statement, Dr. Potrykus posted a follow-up
which states the amount of vitamin A delivered by golden
rice can be determined only when data is available from
- new rice varieties bred by plant breeders,
- bioavailability studies to determine how much provitamin-A
is readily available for absorption by the body, and
- nutritional studies on people with VAD.
This information can only be obtained once the golden
rice trait is transferred to local varieties and produced
in quantities sufficient to support necessary field experiments.
According to Potrykus, the intent of golden rice is to supplement
the diet with vitamin A, not provide 100% of the Recommended
Daily Allowance (RDA). Potrykus maintains the goal of golden
rice having a beneficial effect on vitamin A-deficient people
is realistic with experimental golden rice lines possibly
already in the 20-40% RDA range.
For the full text of Potrykus's statement, see: "Genetically
Engineered 'Golden Rice' is Fool's Gold" Response from Professor
Ingo Potrykus
Who "owns" golden rice?
In a highly debated move, the inventors of golden rice signed
an agreement in May of 2000 through a small licensing company
(Greenovation, Freiburg, Germany) with Zeneca, the crop
protection and plant science business of AstraZeneca. This
agreement gave Zeneca an exclusive license to charge for
commercial use of the golden rice technology. In late 2000,
a merger of the agrochemical division of AstraZeneca and
Norvartis's agrochemical and seed business was completed
to form the company Syngenta, which now holds the license
for the commercial use of golden rice. Also in this agreement,
Syngenta supports the humanitarian use of golden rice, as
intended by the inventors, for developing countries. The
agreement defines humanitarian use as individuals receiving
$10,000 or less income from golden rice (Potrykus
2001). The agreement also applies to all subsequent
applications of the technology to other crop plants. The
inventors claim this move was essential to ensure further
development of golden rice and timely release of the technology
to those who most need it. Arguments for and against the
agreement with AstraZeneca (now Syngenta) and an explanation
by Potrykus on the need for the agreement can be found at
http://www.biotech-info.net/golden.html.
How will golden rice get to those who need it?
Subsistence farmes plowing a field.
Source: www.catholicrelief.org
|
In order to fulfill the inventors'
goal of helping prevent vitamin A-deficiency in the
poor and disadvantaged of developing countries, golden
rice has to reach subsistence farmers free of charge
and restrictions. Co-inventor Ingo Potrykus has outlined
a strategy to get golden rice to poor farmers. As of
March 2001, golden rice consisted of a series of provitamin-A
producing laboratory lines whose traits must be transferred
to locally adapted varieties in rice-growing countries. |
A "Golden Rice Humanitarian Board" was established to
determine which institutions would initially receive golden
rice, and to ensure that all regulations concerning the
handling and use of genetically modified organisms (GMOs)
would be followed. Currently, the Humanitarian Board has
two partner institutions in the Philippines, four in India,
two in China, one in Vietnam, one in Indonesia, and one
in Africa. As of July 2002, the Board was also in discussions
with two institutions in Latin America (Potrykus
2002). The institutions will be responsible for evaluating
the need for golden rice, analyzing and comparing the pros
and cons of alternative measures, and setting a framework
for the implementation of 'golden rice' that best suits
the needs of the areas the institutions serve. In addition,
bioavailability (the degree that the provitamin-A is readily
available for absorption by the body), substantial equivalence
(measures whether a biotech crop or food has similar health
and nutritional characteristics to a conventional counterpart),
toxicology, and allergenicity assessments will be conducted.
The institutions will also be responsible for transferring
the trait into the best locally-adapted lines by traditional
breeding practices and direct-transformation techniques,
as well as ensuring the varieties used will be important
to the poor, and not fashionable varieties for the middle
class. For the details of Potrykus's strategy, see "Golden
Rice and Beyond"
Will golden rice be accepted?
Although the inventors of 'golden rice' claim that the technology
can ultimately contribute to the reduction of vitamin A
deficiency in many poor and disadvantaged people, a number
of organizations oppose its implementation. Some claim that
'golden rice' is a proverbial 'Trojan horse' that uses our
sympathy for the poor and disadvantaged to gain acceptance
for genetically modified crops. Others feel that 'golden
rice' will not be able to provide vitamin A in levels that
will be beneficial, or that malnutrition will prevent the
vitamin A that is available from being absorbed by the body.
Another opinion is that even if 'golden rice' could help
prevent VAD, it would not be socially accepted by cultures
that value a white colored rice. For articles addressing
some of the arguments against 'golden rice' as well as responses
to the articles from supporters of the technology, visit
the web pages in the Additional Resources section below.
Additional Resources
Contains a list of articles and responses on golden rice,
including several letters from the co-inventor of 'golden
rice' Dr. Ingo Potrykus. http://www.biotech-info.net/golden.html
Grains of delusion: Golden rice seen from the ground. February
2001. An article written and published by: BIOTHAI (Thailand),
CEDAC (Cambodia), DRCSC (India), GRAIN, MASIPAG (Philippines),
PAN-Indonesia and UBINIG (Bangladesh) which oppose the implementation
of golden rice. http://www.grain.org/publications/delusion-en-p.htm
Golden Rice- A Golden Chance for the Underdeveloped World.
by Michael Fumento. American Outlook, July-August 2001.
An interview with co-inventor Dr. Ingo Potrykus. http://www.fumento.com/goldenrice.html
Jason Sutton in the Department of Bioagricultural Sciences
and Pest Management at Colorado State University contributed
the content for this page.
'Golden' Rice