golden rice has 20 times more beta-carotene
UK scientists have developed a new genetically modified strain of
golden rice that is said to produce 23 times more beta-carotene than the
previous variety, reports Dominique Patton.
The news raises once again
the complex issue of genetic modification of plants for the benefit of poor
countries. Increasing GM research could also become an issue for the health
New biotech capabilities
are allowing researchers to develop plants with higher amounts of health
nutrients. Last year a team at Bristol University engineered a new strain of
Arabidopsis, a relative of the cabbage, which had substantial quantities of they
fatty acids arachidonic acid (ARA) and eicosapentaenoic acid (EPA).
Another team, in Germany,
designed a linseed plant that accumulates significant levels of PUFA.
Like the new rice, such
developments offer cheaper or more plentiful supply of key nutrients than
current sources, however they also face safety concerns and consumer resistance
to genetic engineering.
Syngenta's original golden
rice, developed in Switzerland five years ago, has not yet been grown in field
trials in Asia, although the firm says that public rice research institutions in
the Philippines, Vietnam, India, Bangladesh, China and Indonesia are in various
stages of developing locally adapted varieties.
Greenpeace has criticised
the lack of information given on the bioavailability of beta-carotene from the
rice in the body, noting that the original variety was also designed to increase
intake of this nutrient but children could not get their daily requirement from
eating normal quantities of rice.
It adds that several other
approaches to solve vitamin A deficiency have been shown to work efficiently and
the Golden Rice project is likely to distract the necessary public awareness of
solutions like vitamin A supplementation and political efforts against
The Golden Rice
Humanitarian Board, chaired by co-inventor of golden rice Professor Ingo
Potrykus from the Swiss Federal Institute of Technology and Professor Peter
Beyer from the University of Freiburg, noted that the rice “is but one tool
in a larger toolbox from which country health officials, farmers and consumers
could choose in their efforts to fight vitamin A deficiency” and that it
could complement existing efforts to eradicate deficiency of the vitamin.
In Asia, the average person
eats rice two or three times a day and it has also has become a staple food in
many African countries. Milled white rice contains essentially no beta-carotene
and unmilled brown rice contains a very small amount.
Rachel Drake and colleagues
from Syngenta discuss the new development in a letter to Nature Biotechnology
(doi:10.1038/nbt1082). “We hypothesized that the daffodil gene encoding
phytoene synthase (psy), one of the two genes used to develop Golden Rice, was
the limiting step in beta-carotene accumulation. Through systematic testing of
other plant psys, we identified a psy from maize that substantially increased
carotenoid accumulation in a model plant system."