Courtesy: Medill Reports Chicago
The DNA for soybeans, a major U.S. crop, has been decoded for the first time, paving the way for a healthier, more bountiful legume, researchers said.
“This is a major milestone because it provides a reference sequence, or what we call a reference genome, not only for soybeans but for some other legumes,” said Scott Jackson, a plant geneticist at Purdue University in West Lafayette, Ind., and lead researcher on the project.
He was part of a collaborative effort by researchers at Purdue, Iowa State, the University of Missouri, University of California, Berkeley and the HudsonAlpha Institute for Biotechnology. Their results were published in Nature last week.
Soybeans are a major crop in the U.S., generating an estimated $28.6 billion in 2008. In Illinois, soybeans are the No. 2 crop, accounting for nearly $3 billion of the state’s $9 billion agriculture industry.
Soybeans are a main food source for livestock, and they are commonly used to make foods such as soy milk and tofu. Soybean oil is also used for cooking and can be found in margarine, mayonnaise and many salad dressings.
Jackson and his team unlocked the sequence by first chopping the genome into millions of random pieces. The entire genome was over 1 billion nucleotides long. By comparison, the human genome is about three times as large. A nucleotide is the individual building block of DNA.
After breaking the genome apart, Jackson then had to re-assemble it, piece by piece.
“It was just sort of a large jigsaw puzzle after that,” he said.
Ken Dalenberg, a soybean farmer in Downstate Mansfield, and a director on the United Soybean Board, said this research promises to help in the fight against pests and diseases, which can often wreak havoc on the industry.
This year, for example, white mold afflicted roughly 10 percent of the soybean crop. Dalenberg said that alone translated into a multimillion-dollar loss for farmers.
Knowing the genome’s sequence could prove especially helpful when dealing with soybean rust, a devastating fungal disease, Dalenberg said.
“We have no true genetic resistance against soybean rust,” Dalenberg said. Spraying fungicide helps, but he said it’s only a temporary solution.
“Without having genetic resistance, we don’t have a long-term cure,” he said.
Brian Diers, a soybean genetics professor at the University of Illinois at Urbana-Champaign who was not involved in the genetic sequencing, said the impact won’t be immediate.
“Sequencing of the soybean genome probably won’t have effects right away,” he said, “but what it will do is basically provide a roadmap to better study the soybean genome.”
Diers estimated that it probably will be a few years until Jackson’s work makes its way onto Illinois farms. However, he noted that it is already proving useful in his own line of research.
Diers is investigating how to enhance soybean resistance to aphids, a small insect pest. The soybean sequence has already allowed his team to identify potentially helpful genes more quickly.
The soybean’s genetic sequence could also help scientists develop varieties that produce a greater yield. Dalenberg said this could translate into cheaper crops. As the yield increases, the cost per unit goes down, he said.
However, even more exciting possibilities lie with alternative fuels. Soybean oil is used in the biodiesel industry, and Jackson’s team has already identified more than 1,000 genes that soybeans use to make oil. And finding those genes, and their eventual end products, is important in making biodiesel, Jackson said.
“The type of oils and fatty acids that you want for, say, biodiesel, are very different that what you want for cooking oil,” Jackson said.
Dalenberg said that less than two percent of soybean oil is used to make biodiesel, but that figure is growing.
So what about the genetically modified food debate? According to Jackson, Diers and Dalenberg, it’s a non-starter.
“In the U.S., it’s sort of a settled, done deal,” Jackson said. “Eighty-plus percent of the soybeans are genetically modified or engineered.”
Todd Loesch
