Hope for the Hungry as Scientists Decode Rice Gene

Seattle Post-Intelligencer

April 5, 2002

Researchers from the University of Washington and China have cracked
the genetic code of rice, a scientific sequencing feat that should lead
to improved grain crops and help reduce hunger and malnutrition around
the world.

The new maps of the rice genome will make it easier for plant breeders to develop hardy, high-yielding versions of a variety of crops without genetic engineering, scientists say.

The breakthrough by UW geneticists Jun Yu and Gane Ka-Shu Wong, in conjunction with a Chinese research group, is detailed in one of two papers dealing with rice genetics being published today in the journal Science.

Wong and Yu sequenced the most commonly grown variety of rice in China and many other Asian-Pacific regions. Rice is a staple for more than half the world's population.

"If you think about why the Chinese want to sequence rice, it's the No. 1 food on the table," said Yu, associate director of the Chinese genome center in Beijing and a UW faculty member. "There is nothing in the Chinese diet that compares with rice."

A group from Syngenta AG's Torrey Mesa Research Institute in San Diego sequenced a different variety of rice. That genetic map also appears in today's Science.

"The future of agriculture will be navigated using the rice genome map," said Steve Briggs, president of the research institute.

Genetic Blueprint Similar to Corn, Wheat

The genetic blueprint of rice is similar to the genomes for corn, wheat and other plants descended from wild grasses. Plant geneticists say the rice map will make it much quicker to identify genetic traits and create new versions of crops by the old-fashioned method of cross breeding.

"Over the past ten years, scientists have worked out the relationship between the layout of the gene sets for all the major cereal crops, so knowing where a gene is on rice will tell us where it is on corn and wheat," Wong said.

"This is important," he said, "because the corn and wheat genomes are six and 40 times larger than rice, so they are much more expensive to sequence."

Syngenta and the UW-China consortium published draft maps of the genomes of separate subspecies of rice. A more complete map is nearing completion by an international consortium of scientists.

This will be the first genetic mapping project "to yield tangible results for humankind from the standpoints of food security and combating malnutrition," the directors of two major international crop research centers wrote in a Science article accompanying the genome reports.

New Rice Varieties Could Be Produced

Stephen Goff, leader of the Syngenta team, said the variety it studied, known as japonica, should reveal the gene that causes production of Vitamin A. That information could speed the development of rice varieties that have higher levels of the nutrient. Vitamin A deficiency is a major cause of blindness in Asia.

Conventional plant breeding is a laborious process, sometimes requiring a decade or more of crossing and back-crossing plants to ensure that the resulting crop variety has the best traits possible. Scientists say knowledge of the rice genome will enable them to find the genetic traits they want in seed banks and then to track those traits through the new plant varieties they're developing.

"It takes what is usually a 12- to 15-year activity to something that takes three or four years. That's pretty major," said Jeffrey Bennetzen, a Purdue University biologist .

By using conventional breeding methods, crop developers avoid the hassle of getting government approval to test and commercialize genetically engineered crops. Biotech crops have met strong consumer resistance in Europe, and some U.S. food companies have shied from using them.

The UW-China effort is the first to release all its data to a public database, Yu said. "We want to encourage the scientific field to conduct more research on rice. The way you push the field forward is by providing information."

In a controversy that mirrored the publication last year of the human genome, some scientists have criticized the withholding of rice genome data by private companies. Syngenta, part of a Swiss-based agrichemical company, plans to maintain a proprietary database of its genomic information.

Syngenta intends to start field-testing this summer a variety of corn that was developed using the rice data to be more resistant to cold, damp weather in the spring.

The genome mapping suggests rice may have more genes than humans. The genome of the indica type studied by the UW-China group is believed to contain 45,000 to 56,000 genes, compared with 30,000 to 40,000 for humans. The japonica subspecies is believed to have 42,000 to 63,000.

"As for rice perhaps having more genes than humans, it was a slight blow to my human-chauvinistic views of the world," Wong said. "But if there's one thing that makes us special, compared to plants, it's our brain. The bottom line is I am clinging to my human-chauvinistic views."

Copyright 2002, Seattle Post-Intelligencer