Gene-Altered Rice May Help Fight Vitamin A Deficiency Globally
By Guy Gugliotta
The new "golden rice," the result of a research investment of more than $100 million over 10 years, contains three transplanted genes that allow plants to produce rice kernels carrying beta-carotene, a compound that is converted to vitamin A within the human body.
Ingo Potrykus, the Swiss biotechnologist who led the Vitamin A research, said his team is also completing work on another genetically modified rice strain with increased iron content. Iron deficiency-anemia, the world's worst nutrition disorder, affects nearly 2 billion people.
Economic development experts described the vitamin A rice, reported today in the journal Science, as an electrifying breakthrough in efforts to improve the health of billions of poor people, most of them in Asia.
"We cannot reach very many of the malnourished in the world with pills," said Per Pinstrup-Andersen, director general of the International Rice Research Institute. "We have to build the nutrient content of the foods they eat."
Pinstrup-Andersen also suggested that the new rice could provide a public relations boost for plant biotechnology, damned by some environmentalists and consumer activists for promoting "frankenfoods" engineered for high yields, pest resistance and other traits.
"For years consumers have asked, 'What's in it for me?' because the benefits all went to farmers," Pinstrup-Andersen said. "Something like this will help people understand [biotechnology's] tremendous potential."
Although the beta-carotene genes have survived across several generations of engineered laboratory plants, the Philippine-based rice research institute must now put the trait into commercially useful rice strains.
Researchers can either breed the lab strain into a commercial variety through traditional techniques, a process that will take four to eight years, or try to insert the new genes directly into commercial varieties and track them for two years to see if the beta-carotene trait will move to a third generation, said institute biotechnologist Swapan Datta.
"We will probably use both methods," Datta said. Once researchers produce crops of viable seed rice, the institute will offer the new rice free to any nation that wants it. World rice production in 1999 has been estimated at 396.5 million metric tons, 94 percent of which was produced in Asia.
Research on the new rice began in the aftermath of the so-called "Green Revolution," the movement to breed new, high-yield strains of basic grains for individual habitats in the developing world.
The results for rice were spectacular. Production in Asia, where more than 90 percent of the world's rice is consumed, grew by 116 percent between 1966 and 1997, according to the institute.
During the same period, however, Asia's population grew from 1.9 billion to 3.5 billion, with more than 900 million living in poverty. By the mid-1980s, "we believed that rice yields had reached their maximum," said Robert W. Herdt, vice president for program administration at the Rockefeller Foundation, the Green Revolution's main sponsor.
"We became convinced that research in biotech to address that problem was a high priority," Herdt added. The idea of putting a vitamin into rice did not mature until 1990 when Potrykus, a plant biotechnologist at the Institute of Plant Sciences in Zurich's Swiss Federal Institute of Technology, proposed the vitamin A project.
By 2000, Herdt said, the foundation had spent $100 million on rice biotechnology. The researchers also obtained funding from the Swiss Federal Institute and the European Community Biotech Program.
The Zurich team knew that milled rice contains a beta-carotene precursor compound but is unable to convert the precursor into beta-carotene itself.
Beta-carotene, the yellow-orange compound that gives carrots their color, is the world's most common source of vitamin A. Those who lack it suffer from vision impairment, which can lead to blindness, and are more susceptible to a host of other diseases. The United Nations estimates that vitamin A deficiency may cause 2 million deaths each year among children under 5 years old.
After several false starts, Zurich team member Xudong Ye was finally able to engineer a strain of beta-carotene-rich laboratory rice by combining three genes outside the plant and inserting them simultaneously into the chromosome in two packages.
This, said Dartmouth College biologist Mary Lou Guerinot, was a "technical tour de force" because most traits are engineered in plants with a single gene. The vitamin A package borrowed two genes from the daffodil and a third from a bacterium. When polished rice from the mature plants showed a rich golden color, "it was fantastic," Potrykus said.
The iron research also involves three genes, but these are inserted separately, Potrykus said. By March, he said, he will have the first mature genetically engineered rice plants to have both the vitamin A and iron modifications.
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