Researchers at SIUC and Texas A&M College Station have completed the world's first entire "physical map" detailing the general lay of the soybean's genetic landscape.

Details were announced as part of a multi-author review of legume genomics in the March 2003 issue of Plant Physiology, published by the American Society of Plant Biologists.

"The map is now available to the entire research community in an open source code format. Basically, anyone can take everything we have done over the last four years, download it onto a computer, and begin working with it," says SIUC plant biotechnologist David Lightfoot, who heads the joint research team. His A&M colleagues are Chencang Wu and Hongbin Zhang.

A genome consists of a life-form's entire package of chromosomes, genes, and DNA. A map helps researchers find their way around the genome by identifying certain "landmarks"--known genes or bits of DNA, for example--and their relative distances from each other.

"Think of it as a framework that provides places to hang information," Lightfoot says. "Once you can link together all those hanging bits of information (with no gaps), you will have the entire sequence of the genome."

Sequencing plays a key role in genetic research because it [identifies and] pinpoints the exact location of every bit of genetic material. "Position is important in knowing what a gene does," Lightfoot says.

Making the map available to researchers worldwide should speed up the sequencing process, he adds.

The SIUC team also is planning to work with 10 researchers from other states to use the map in identifying valuable genes in the soybean's makeup.

The National Science Foundation's Plant Genome Program has underwritten the work done so far.

With additional funding, says Lightfoot, "we think we could capture about 80 percent of the genes we're looking for through a combination of further improvement of the physical map and some gene enrichment technologies that would allow us to hook those genes out of the genome and sequence them."

While locating these genes ultimately will help scientists breed a better bean, results also could lead to improvements in lentils, chickpeas, clover, and other members of the legume family. Lightfoot, one of 26 scientists from around the country who have joined forces to work on legumes, says some members of this group are trying to sequence a fodder crop called barrel medic, while researchers in Japan are focusing on the Japanese version of another fodder crop, birdsfoot trefoil.

"Once we know where the genes go in soybean, we can compare that with where they go in barrel medic and [birdsfoot trefoil]," Lightfoot explains.

"We hope to see that the same genes go together in blocks in all three. If that's the case, we could then predict which genes would be neighbors in all legumes."

From there, it wouldn't take much to pin down what each one does and begin harnessing the most helpful to produce legume "Supercrops."

In some respects, legumes have already achieved star status in the crop world. They play a huge role in feeding the world's peoples and animals, particularly in Third World countries, where they meet as much as two-thirds of human nutritional needs. And because they can pull nitrogen out of the air, they don't need a lot of chemical fertilizers.

That makes legumes a bargain for poor farmers who can't afford fertilizers and a boon to richer ones whose overuse of farm chemicals can lead to water, soil, and air pollution.

But they could be even better, Lightfoot believes.

"Legumes do wonderfully when it rains, not so good when the water is not there--and everything eats on beans," he says. "Being able to build in resistance to drought, disease, and pests is an important target."

Genetic knowledge of legumes might also lead to improvements in other crops.

"There's a lot of complexity built into these plant mechanisms," Lightfoot says.

"If we can understand enough about how they work, maybe we can transfer that knowledge to other plants."

--by K. C. Jaehnig, Media & Communication Resources

Fall 2003 Contents | Perspectives Home | SIUC Home