NSF awards WUGSC, CSHL, AGI and ISU $29.5M to sequence the corn genome

UA-bred technology will lead effort to lay corn's genome bare

Scientists embarking on an ambitious $29.5 million effort to uncover corn's genetic code will use an approach developed by UA researchers to drastically reduce the project's time and cost.

Researchers at the University of Arizona's Bio5 Institute will join colleagues at three other universities in the effort to decode the complete DNA sequence of the corn plant, the second major effort in sequencing the genome of a food crop for the UA. The Maize Genome Sequencing Project was announced Tuesday by the National Science Foundation.

Leading the UA team is Rod Wing, professor of plant sciences and director of the plant genomics institute. He developed technology that provides a so-called physical map of the genome, enabling researchers to focus solely on genes, looking past stretches known as "non-coding" DNA.

With Wing's approach, scientists can sequence the genome at a fraction of the cost in time and money it took to decipher the human genome, which isn't much bigger than corn's. The Human Genome Project was a $3 billion, 13-year effort.

The UA scientists join colleagues at Washington University in St. Louis, Iowa State University in Ames and Cold Spring Harbor Laboratory in Cold Spring Harbor, N.Y. About $6 million will come to the UA over the course of the four-year project. Carol Soderlund, a Bio5 researcher, developed software that will be used to generate the genetic map.

The UA has already collaborated with Washington University and the Cold Spring Harbor Laboratory on a project to sequence the rice genome, which was published in the journal Nature in August. Rice was the first food crop to have its full genome sequenced.

While the rice genome research was a breakthrough, sequencing the corn genome is daunting because of its larger size and more complex genetic arrangements. According to the National Science Foundation, it contains an estimated 50,000 to 60,000 genes scattered among the 2.5 billion bases of DNA that make up its 10 chromosomes. By comparison, the human genome contains about 2.9 billion bases and about 26,000 genes.

"The rice genome is really one of the best examples of very accurate sequencing work," said Rob Leonard, plant sciences department head.

The fact that the National Science Foundation awarded so much of its resources for this project to one group bodes well for the UA and the Bio5 Institute, he said.

"It goes to show just how well-thought-of our work in genetics and plant genomics is viewed nationally," he said. "And that's in large part because of Wing's great success in the rice sequencing project.

"We're viewed now as one of the major players in plant- genome sequencing."

The implications of genome sequencing stem from an understanding of the plants' makeup, which in turn leads to experiments designed to improve the crops, producing varieties that are more disease-resistant, grow in different climates or with less water, are more nutritious and have a greater yield, scientists say.

"What this program is going to yield is the knowledge of the structural nature and organization of genes in a corn plant, which will also give a lot of information about the genes that exist in most cereal plants," said Brian Larkins, a UA regents' professor of plant sciences. "You have a template you can use to more or less dissect all of the gene expression patterns in a developing plant."

Scientists could potentially use that information to change the nature of the kinds of starches, protein and oils in seeds, improving the crops.

Improvements don't even have to come from the controversial area of genetic engineering, Larkins said. By applying knowledge of the genome, scientists can use various genes simply as markers for conventional breeding.

"If you can apply that to all cereal crops, then it can dramatically accelerate the development of improved varieties," he said.

● Contact reporter Eric Swedlund at 573-4115 or at eswedlund@azstarnet.com.