US - A new type of soybean with low allergen content and better nutritional properties has been conventionally bred by scientists from the Universities of Arizona and Illinois.
In the United States, nearly 15 million people and 1 in 13 children suffer from food allergy, and soybeans contain several allergenic and anti-nutritional proteins that affect soybean use as food and animal feed.
A decade-long effort by scientists has yielded a new soybean with significantly reduced levels of three key proteins responsible for both its allergenic and anti-nutritional effects.
"We have created a low-allergen and low anti-nutritional inhibitor soybean using conventional breeding methods," said Eliot Herman, a professor at the University of Arizona and an author on the study.
Back in 2003, Professor Herman, then at the US Department of Agriculture, made national headlines when he and his colleagues addressed P34 as the soybean's key allergen, and genetically engineered it out of the crop.
Although the new soybean may have been less likely to cause allergic reactions, testing was impeded by its transgenic production especially in key applications such as infant formula.
To circumvent the issue, the scientists set out to create a similar soybean using conventional breeding methods.
After screening 16,000 different varieties of soybean for the desired trait, they found one that almost completely lacked the allergen P34.
The team combined this variety with two varieties, previously identified by co-author Theodore Hymowitz from the University of Illinois, that lacked soybean agglutinin and trypsin inhibitors. These proteins are responsible for the soybean's anti-nutritional effects in livestock and humans.
"We really believed in this goal and wanted to produce an enhanced soybean that could be used," Mr Herman said. "That became the motivation for using conventional breeding rather than the transgenic approach."
After nearly a decade of crossbreeding each variety to the soybean reference genome called Williams 82, the team has produced a soybean that lacks most of the P34 and trypsin inhibitor protein, and completely lacks soybean agglutinin.
Beyond these characteristics, the soybean is nearly identical to Williams 82. The team has dubbed the new variety "Triple Null."
"We think this will be embraced by many, whether they prefer conventional breeding or transgenic methods of food production," said Monica Schmidt, an assistant professor at the University of Arizona and the lead author of the study.
"It can be grown organically, with pesticides, and although conventional itself it could be transformed to add other producer or consumer traits."
In collaboration with scientists at Purdue University, tests are planned to evaluate the efficacy of the low-allergen soybean in swine.
The Purdue team has bred a line of swine that develops a strong allergenic response very similar to that of human infants allergic to soybean formula. The swine studies will enable testing of Triple Null and enable new approaches to mitigate soybean allergies in humans.
Mr Herman explained: "We hope this work will offer a new approach to developing low-allergen foods and help to bend down the curve of growing food allergy."
Triple Null also has applications for livestock and agriculture with soybean being the primary global input of vegetable protein for animal feed and aquaculture.
Before soybean is used in feed, it must undergo a heating process to eliminate anti-nutritional proteins that the scientists eliminated in the new variety, hence it provides opportunities for cost savings.
Mr Herman said. "At the current rate, we'll have to more than double the amount of animal feed by the year 2050. This means that several hundred million more tons of soybean will need to be processed before it can be fed to animals."
By preemptively knocking out the anti-nutritional components of soybean, the researchers hope Triple Null can eliminate the need for extra processing and make creation of animal feed more efficient, potentially developing a raw soybean as animal feed.
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