The United States Department of Agriculture identifies 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 Crop Science Association, will explore how we can use breeding to develop less allergenic types of these foods. Rustgi recently presented his research at the 2020 ASA-CSSA-SSSA AGM.
Allergic reactions caused by wheat and peanuts can be prevented by avoiding these foods, of course. “While that’s simple, it’s difficult in practice,” Rustgi says.
Avoiding wheat and peanuts means losing healthy food choices. Both of these foods are nutritional power plants.
Wheat is a good source of energy, fiber and vitamins. Peanuts provide protein, good fats, vitamins and minerals.
“People with food allergies can try hard to avoid the foods, but it is possible to inadvertently appear allergenic,” says Rustgi. Allergies can lead to hospitalization, especially for people with peanut allergies.
“For others, wheat and peanuts are not easy to avoid for geographical, cultural or economic reasons,” Rustgi explains.
Rustgi and his colleagues are using plant breeding and genetic engineering to develop less allergenic varieties of wheat and peanuts. Their goal is to increase food choices for people with allergies.
For wheat, researchers focus on a group of proteins, called gluten.
The gluten in bread flour makes an elastic dough. Gluten also contributes to the delicate texture of bread.
But gluten can trigger an immune response in individuals with celiac disease. In addition, others experience non-celiac gluten sensitivity, leading to a number of adverse symptoms.
Researchers have been trying to breed wheat varieties with lower gluten content. The challenge, in part, lies in the complex nature of gluten genetics. The information needed to make gluten is rooted in the DNA in wheat cells.
But gluten is not one protein – it is a group of many proteins. The guide cells needed to make the individual gluten proteins are in different genes.
In wheat, these gluten genes are distributed throughout cell DNA. Because so many portions of DNA play a role in gluten formation, it is difficult for plant breeders to reproduce wheat varieties with lower gluten levels.
When we began this research, a key question was whether it was possible to work on a feature that was controlled by so many genes. “
Sachin Rustgi, Member of the American Crop Science Association
For peanuts, the situation is similar. Peanuts contain 16 different proteins known as allergens.
“Not all peanut proteins are equally allergenic,” says Rustgi. Four proteins stimulate an allergic reaction in more than half of nut-sensitive individuals.
Like the gluten genes in wheat, the peanut allergen genes are distributed throughout the peanut DNA.
“Achieving these many targets is no easy task, even with current technology,” says Rustgi.
Rustgi and the research team are testing many types of wheat and peanuts to find some that are naturally less allergenic than others.
These low-allergenic varieties can be bred with crop varieties that have desirable symptoms, such as high yield or pest resistance. The goal is to develop commercially grown low-allergenic wheat.
In addition to traditional breeding efforts, Rustgi also uses genetic engineering to reduce allergenic proteins in wheat and peanuts.
For example, a technology called CRISPR allows scientists to make very precise changes to cell DNA.
Rustgi uses CRISPR to target gluten genes in wheat. Recent advances in CRISPR technology allow researchers to target multiple genes simultaneously.
CRISPR-targeted genes are altered or translocated. This means that cells can no longer ‘read’ these genes to make the specific proteins.
“Disturbing the gluten genes in wheat could result in wheat production with significantly lower levels of gluten. A similar approach would work in peanuts,” says Rustgi.
Other approaches include understanding how gluten production is regulated in wheat cells. As it turns out, one protein serves as a ‘key regulator’ for many gluten genes.
That’s important because disturbing this key regulator could lead to lower gluten levels in wheat. It is easier to target one gene than to try to disturb several gluten genes.
“Wheat and peanuts are the main sources of protein for many, especially those living in conditions where there are no resources,” says Rustgi. “Finding affordable ways to provide wheat and peanuts to all is very important.”
The development of wheat and peanuts with lower levels of allergens is a key step towards this goal.
These crops also reduce inadvertent exposure to allergens. Also, they would limit the severity of reactions if they occurred. “
Sachin Rustgi, Member of the American Crop Science Association
Source:
American Agronomy Association