Urbana, Illinois
May 4, 2006Researchers
have isolated two Chinese soybean lines that grow without the
primary protein linked to soy allergies in children and adults.
The two lines already are adapted to Illinois-like conditions
and will be given away to breeders seeking to produce new
varieties of allergy-free soybeans without genetic engineering.
Crop scientists at the
University of Illinois at
Urbana-Champaign and the
Donald Danforth Plant
Science Center in St.
Louis screened more than 16,000 soybean lines kept in the USDA's
National Soybean Germplasm Collection. The findings will appear
later this year in the journal
Crop Science.
The two soybean lines (PI
567476 and PI 603570A) contain virtually identical genetic
mutations that do not contain the leading allergy-causing P34
protein, which consists of 379 amino acids, said Theodore
Hymowitz, emeritus professor of plant genetics in the crop
sciences department at the U. of I.
"We are releasing this
information with no patents so that companies and breeders
involved with soybeans can incorporate these two lines as
quickly as possible," Hymowitz said. Companies in Japan, Canada
and across the United States have been following the research
effort, he added.
The research, which was funded
primarily by the Illinois-Missouri Biotechnology Alliance, went
through two stages.
First, using a specially
developed immunochemistry approach, Hymowitz's post-doctoral
assistant Leina M. Joseph examined 100 lines of soybeans per day
for nine months from the UI-based collection. Seeds were
crushed, treated and placed on a membrane for screening. A
second screening using stronger antibodies and protein gels was
done to confirm the absence of P34 in the two domestic lines,
Joseph said.
After the two lines were
isolated, seeds were sent to the Danforth Center for additional
molecular analysis to determine why P34 was absent. Six
identical genetic mutations were found in each, indicating the
two lines may be related, Hymowitz said.
"The lack of the protein was
confirmed by more-detailed two-dimensional protein assays," said
Eliot M. Herman, a lead scientist at Danforth who probed the
seeds with post-doctoral researcher Monica A. Schmidt. "We then
isolated the gene responsible for the lesion, and we found there
was a single significant change in the gene's sequence that
likely produced a protein which could not be made as a stable
product."
Herman discovered P34 in the
early 1990s and in 2003 had successfully used a gene-silencing
technique to create a soybean line in which P34 was "knocked
out." However, because of public resistance to genetically
modified products researchers have been seeking a more
traditional approach. Because the newly identified lines occur
naturally, they can be successfully crossed into other soybean
lines "without any biotechnology-derived component," the
researchers noted.
"Soybeans are slowly but surely
increasingly being used in the foods we eat, and with that we
are noticing an increase in the number of children and adults
that have allergies to soybeans," Hymowitz said.
Currently, 6 percent to 8
percent of children are allergic to soy-based products,
including infant formulas, while 2 percent of adults have had
allergic reactions, which range from harmless skin reactions and
gastrointestinal irritation to more serious facial swelling,
shortness of breath, difficulty swallowing and fainting.
Avoiding soy products is
becoming more difficult because of soy's use as fillers and
components of many menu items. While people can read labels
before preparing meals at home, avoiding soy at restaurants
isn't as easy, Hymowitz said. |