Genetic Technology Helps Wheat Make Better Bread, Says UF Expert

By:
Tom Nordlie (352) 392-1773 x 277

Source(s):
Indra Vasil ikv@mail.ifas.ufl.edu, (352) 392-1193
George Lookhart george@usgmrl.ksu.edu, (785) 776-2736
Jane Muir jmuir@ufl.edu, (352) 846-1646, ext. 210

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GAINESVILLE, Fla. — Average wheat varieties could be given superior bread-making qualities, thanks to genetic technology developed at the University of Florida’s Institute of Food and Agricultural Sciences.

“Traditionally, the bread-making characteristics of wheat differ from one variety to another,” said Indra Vasil, graduate research professor emeritus with UF’s Department of Horticultural Sciences and leader of a group that developed the technology. “Wheat that’s easy to grow doesn’t always make good bread, but if it did we could save time and money.”

Wheat’s unique bread-making properties come from complex proteins called glutenins, found in no other cereal grain, Vasil said. Glutenins with high molecular weight (HMW glutenins) make stronger, more elastic dough, which yields chewier bread.

“By controlling HMW glutenins, we can have the best of both worlds,” he said. “We can take a wheat variety that’s very hardy and economical to grow but has poor bread-making qualities and turn it into a good bread-making wheat.”

Wheat varieties used for bread have a genetic structure with three separate sets of chromosomes, Vasil said. Each set has one pair of genes that control HMW glutenins.

“Theoretically, a wheat plant could have all six genes coding for HMW glutenins,” he said. “But in nature it doesn’t work that well. In most wheat varieties, only three to five of these genes are expressed.”

Vasil said traditional breeding methods have been ineffective at manipulating HMW glutenins, because the pairs of genes are so closely linked that the genes cannot be influenced individually. To solve the problem, Vasil devised a method to introduce a naturally occurring wheat gene, known as 1Ax1, into wheat plants. The gene is normally associated with production of HMW glutenins found in wheats with good bread-making qualities.

Vasil and other UF researchers produced the world’s first genetically engineered wheat in 1992. In 1996 they introduced the 1Ax1 gene into a common wheat variety called Bobwhite. The result, technically known as a transgenic crop, was the first known example of a wheat plant that expressed six HMW glutenin genes. During the mid-1990s, funding for the research was provided by the Monsanto Corporation.

In the fall of 1996 Monsanto planted a crop of the transgenic Bobwhite wheat, and after its harvest the following spring, Vasil and a team of experts from the U.S. Department of Agriculture and Kansas State University tested the resulting grain, publishing their results in the Journal of Plant Physiology, Vasil said. It was the first time field test results from a transgenic wheat crop had been published.

Compared to ordinary Bobwhite, the improved variety had 61 percent more HMW glutenins and produced bread that was chewier, contained about 10 percent more protein and had up to 10 percent greater loaf volume, he said. There was no loss of nutritional value or wheat yield.

Vasil said this was the first bread produced with transgenic wheat, but don’t look for similar products on grocery store shelves yet — the UF variety is not currently being farmed.

The technology used to produce the improved Bobwhite wheat is more significant than the variety itself, said George Lookhart, a USDA research chemist in Manhattan, Kansas, who characterized the glutenin proteins and helped evaluate the wheat’s nutritional value.

“Since this technology opens the door for any number of beneficial genes to be introduced to any number of wheat varieties, it’s really a question of what producers, industry and consumers want accomplished,” said Lookhart, who is also an adjunct professor at Kansas State University’s Department of Grain Science and Industry.

UF has obtained a patent on the method Vasil’s research team developed to introduce genes into wheat plants, and also patented the more specific process used to increase HMW glutenins in wheat by introducing the 1Ax1 gene, said Jane Muir, associate director for UF’s Office of Technology Licensing.

“We are seeking licensing partners for both patents,” Muir said. “We’re especially excited about this work because more than half the world’s food supply comes from cereal grains, of which wheat is the most important. So this technology has global implications.”

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Posted: February 14, 2002


Category: UF/IFAS



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