TUCSON, Ariz. (AP) — Scientists have completed sequencing the highly complex genome of the maize plant and say the accomplishment could herald a second "green revolution" in more productive and nutritious cereal crops.
Much of the work for the four-year, $30 million collaborative effort by 150 researchers to create a genetic road map for future manipulation of the maize plant was done at the University of Arizona's Arizona Genomics Institute.
The ultimate goal of the push to decode the genomes of food crops is ending world hunger through a "safe and secure food supply," said Rod Wing, the institute's director. Wing's lab previously produced a genetic map for the rice plant.
"Seed companies and maize geneticists will pounce on this data to find their favorite genes," said Richard K. Wilson, in a news release from Washington University in St. Louis.
Wilson is director of Washington University's Genome Center and senior author of the paper detailing the work of the Maize Genome Sequencing Consortium, published in the Nov. 20 edition of the journal Science.
Researchers at Cold Spring Harbor Laboratory in New York and Iowa State University in Ames also played key roles in the study.
"This should greatly accelerate the improvement of corn overall," said Brian Larkins, a UA plant scientist who was not involved in any of the studies.
Larkins, who has devoted four decades to improving the nutritional quality of corn, said "having this knowledge of the genomic structure allows scientists to very accurately dissect what happens during the breeding process. It makes it easier to make novel combinations of genes."
Corn is an important crop, accounting for $47 billion of the U.S. farm economy, according to the report in Science.
Corn is mostly used in this country, though, for fuel, animal feed and in high-fructose, low-nutrition, processed foods.
While only 5 percent to 10 percent of the corn crop "ends up as corn flakes or tortillas," it is an important food crop, said Larkins, which has "spread all over the world" from its beginnings as a domesticated crop in Mexico and Meso-America 10,000 years ago.
"Certainly, there are things that can be done to improve the crop in terms of its protein quality, its nitrogen-use efficiency, yield potential and other traits, including vitamin and mineral content," Larkins said.
To those who oppose genetic manipulation, Larkins points out: "Corn is basically a genetically engineered crop. It started 10,000 years ago, and we've been manipulating it ever since."
UA entomologist Bruce Tabashnik, who has studied inadvertent and unwelcome effects of genetic modification of plants, said this breakthrough should actually aid efforts to avoid such things.
"Knowledge is power, and we will have the power to do many things that weren't conceivable before. The challenge will be to use that knowledge and power wisely," said Tabashnik, who is not connected to any of the studies.
"I think it's really important to make the distinction between an advance in fundamental knowledge and the application of that knowledge to advance specific goals. What my colleagues have done is a wonderful, breathtaking achievement."
In a flurry of related articles published the same day in Science, the Proceedings of the National Academy of Science and the Public Library of Science Genetics, scientists at the UA and elsewhere unveiled 13 studies that mine the data for additional discoveries.
Yeisoo Yu, a research associate professor at the Arizona Genomics Institute, worked with Wing on the map of the maize strain known as B73 and also co-authored a companion study with the UA's Carol Soderlund that identified sets of characteristics that are unique to maize.
The maize genome — which contains its entire set of DNA — is the biggest plant genome decoded so far, he said.
It contains 2.5 billion base pairs covering 10 chromosomes, with 85 percent of its DNA composed of transposable elements, according to a release from the National Science Foundation, which bankrolled the study, along with the U.S. Departments of Agriculture and Energy.
"The genome itself is very complex, even more so than the human genome," Yu said.
Advances in genetics helped the researchers decode maize, creating both a genetic and physical map of the corn strain in less than four years. The earlier human genome effort took many more researchers and 13 years to complete.
"Now the technology is very advanced," said Yu, who said the knowledge gained from this project would make future efforts even simpler.
It was still a challenge, Wing said in a telephone call from Manila, where he was attending an international conference on rice genetics.
The draft of the maize genome was completed in Wing's lab in February 2008. Then, he said, researchers at Washington University, the UA and Cold Spring Harbor in New York "began to edit it to a final product."
He compared it to trying to "edit" a 16,000-word paper in which all words and all the letters within the words are scrambled.
Now, though, the genome is "anchored to a genetic map, ordering the traits like yield, plant height, resistance to drought and others," Wing said.
"If you now have a trait for yield, you can go to the genome and say this one has 20 genes, and one of them is probably a gene for that.
"This is going to be a major contribution to plant biology and plant genetics," Wing said. "Maize and rice are some of the most important cereals in the world. By releasing this highly edited genome, we empower scientists around the world for new discoveries to face the looming challenge of producing a safe and secure food supply."