The US Department of Agriculture has identified a group of “big eight” foods that cause 90% of food allergies. These foods include wheat and peanuts.
Sachin Rustgi, a member of the American Plant Science Society, is exploring how we can use pedigree to develop less allergenic types of these foods. Rustgi recently presented his research at the Virtual 2020 ASA-CSSA-SSSA Annual Meeting.
Allergic reactions to wheat and peanuts can certainly be prevented by avoiding these foods. “While it sounds simple, it’s hard in practice,” says Rustgi.
Avoiding wheat and peanuts means losing healthy food choices. These two foods are the center of nourishing power.
Wheat is a great source of energy, fiber and vitamins. Peanuts provide protein, good fats, vitamins and minerals.
“People with food allergies can work hard to avoid food, but it’s also possible to have an accidental allergy,” says Rustgi. Allergen exposure can lead to hospitalization, especially for people with peanut allergies.
“For others, escaping wheat and peanuts is not easy for geographical, cultural or economic reasons,” Rustgi explains.
Rustgi and colleagues use plant breeding and genetic engineering to develop less allergic varieties than wheat and peanuts. The goal is to increase food choices for people with allergies.
For wheat, researchers are focusing on a group of proteins called gluten.
The bread itself makes the dough elastic. Gluten also helps the chewing texture of bread.
However, it can cause an immune response in people with celiac disease. In addition, others experience non-celiac gluten sensitivity, which causes a variety of negative symptoms.
Researchers are trying to grow varieties of wheat with a lower content of wheat. The difficulty lies, in part, in the complex nature of gluten genetics. Information needed to prepare gluten DNA in wheat cells.
But it is not a single protein in itself – it is a very different group of proteins. The instruction cells needed to make individual gluten proteins are present in different genes.
In wheat, these gluten genes are transmitted to the cell’s DNA. Because so much of the DNA plays a role in gluten production, it is difficult for plant growers to grow wheat varieties at lower gluten levels.
“When we started this research, the big question was whether it was possible to work on a trait that was controlled by so many genes,” he says.
The situation is the same for peanuts. Peanuts contain 16 different proteins known as allergens.
“Not all peanut proteins are equally allergic,” says Rustgi. Four proteins trigger an allergic reaction in more than half of peanut-sensitive individuals.
Like the gluten genes in wheat, the peanut allergy genes are transmitted to peanut DNA.
“It’s not an easy task with existing technology, to affect the target too much,” says Rustgi.
Rustgi and the research team are testing varieties of wheat and peanuts to find one that is naturally less allergenic than others.
These low-allergenic varieties can be grown with high-yielding or pest-resistant crop varieties with desirable characteristics. The goal is to develop low-allergenic wheat that can be grown commercially.
In addition to traditional breeding efforts, Rustgi also uses genetic engineering to reduce allergic proteins in wheat and peanuts.
For example, a technology called CRISPR allows scientists to make very precise changes in a cell’s DNA.
Rustgi uses CRISPR to target gluten genes in wheat. Recent developments in CRISPR technology allow researchers to target multiple genes at once.
Genes targeted by CRISPR are altered or mutated. This means that cells can no longer ‘read’ these genes to form specific proteins.
“Breaking the gluten genes in wheat can result in wheat that is significantly lower in gluten. A similar approach would work in peanuts, ”Rustgi said.
Other approaches include understanding how gluten production is regulated in wheat cells. As can be seen, a protein acts as a ‘master regulator’ for many gluten genes.
This is important because breaking this basic regulator can lead to low levels of gluten in wheat. Targeting a single gene is easier than trying to destroy several genes.
“Wheat and peanuts are a great source of protein, especially for those who live without them,” he said. “It’s very important to find affordable ways to make wheat and peanuts accessible to everyone.”
Growing wheat and peanuts by reducing allergen levels is a step towards this goal.
“These products will also reduce the risk of accidental allergies,” says Rustgi. “Also, if exposure occurred, they would limit the severity of the reactions.”
Sachin Rustgi is a researcher at Clemson University. This work was supported by the South Carolina and National Peanut Councils, the Life Sciences Discovery Foundation, and Clemson University. 2020 ASA-CSSA-SSSA Annual Meeting, adopted by the American Agronomic Society, the American Plant Science Society and the American Society of Soil Sciences.