Gluten is a group of proteins found in some cereal grains, most notably wheat. While foods containing gluten are part of a healthy diet for people across the globe, these proteins can be detrimental for people with certain food intolerances.
To help people with gluten sensitivities or intolerances be better able to digest foods containing wheat, researchers are determining how to manipulate genes to breed for wheat varieties that do not produce these proteins. Sachin Rustgi, a molecular breeder at Clemson University’s Pee Dee Research and Education Center (REC) near Florence, South Carolina, is leading a grant-funded study using conventional and genome-editing methods to develop reduced immunogenicity, lysine-rich genotypes for use in developing new wheat varieties.
“The long-term goal of this research is to remove immunogenic-gluten proteins, not wheat, from the diet,” Rustgi said.
The two main protein types in gluten are glutenins and gliadins. Glutenins are responsible for dough strength and elasticity. Gliadins provide cohesiveness and extensibility, or stretchiness, to wheat dough and is believed to cause most of the negative health effects. In addition, this protein complex also causes celiac disease, which, if left unchecked, can lead to autoimmune disorders in some people. Other people may experience non-celiac wheat sensitivity with myriads of intestinal and extra-intestinal symptoms.
Lysine is an amino acid, a building block of protein, necessary for human health. Because the body cannot make this amino acid, it must come from food or supplements. Fortifying wheat with lysine can help provide humans with this amino acid.
During this project, researchers will use a novel combination of multi-gene editing and nanoparticle-based gene delivery to alter genes responsible for producing gliadin and glutenin proteins to develop non-immunogenic wheat genotypes. They also will determine commercial acceptance of reduced-immunogenicity wheat lines.
“Millions of people suffer from gluten-related diseases,” said Zachary Jones, a plant and environmental sciences graduate student involved in the study. “We believe providing wheat varieties with a reduced content of immunogenic proteins can offer affordable solutions to everyone.”
Wheat is one of the primary crops grown in Uttar Pradesh (Northern Province), India, where Rustgi grew up. Celiac disease is prevalent in India, affecting about 1.04% of the population. This figure is similar to what has been reported in Western countries. Diarrhea is one symptom of celiac disease. Other symptoms are bloating, constipation, gas, lactose intolerance, nausea or vomiting, pain in the abdomen and loose, greasy, bulky and bad-smelling stools.
“For a long time, Celiac disease was misdiagnosed as ‘summer diarrhea’,” Rustgi said. “People in northern India prefer to eat corn chapatis, unleavened flatbread, in winter and wheat bread in the summer. Eating wheat bread in the summer caused celiac symptoms to appear during the summer months.”
Rustgi’s focus has been on improving wheat productivity.
“During my postdoctoral years, news began to come that summer diarrhea, a killer of children and older adults, is none other than Celiac disease,” he said. “Additionally, I met and interacted with many individuals in Pullman, Washington, who have celiac disease—making me feel that I should work to develop an affordable solution to this problem. The research we are conducting knows no boundaries and is applicable beyond borders.”
In addition to studying how to develop wheat varieties with reduced gluten content, the researchers also will look at the role public opinion plays in social and commercial acceptance of the reduced immunogenicity wheat lines. Surveys will be conducted to get consumer opinions on using genome editing to develop reduced-immunogenicity, high-lysine wheat lines.
Interns from local high schools will be recruited to work on the project at the Pee Dee REC during summer months. High school students working on the project will be afforded training in science, technology, engineering and math, or STEM.
“This student training will help develop a highly skilled future workforce and the Outreach/Cooperative Extension Service component of this study will help improve producer literacy about genome editing technology, as well as reduce or eliminate misconceptions,” Rustgi said. This research is being conducted on wheat grown in fields and tested in laboratories in Clemson’s Advanced Plant Technology Program located at the Pee Dee REC. Joining Rustgi and Jones in this research are Charles Rice, a Clemson biology professor, Nishanth Tharayil, a Clemson plant ecophysiology professor and director of the Multi-User Analytical Laboratory, Gaganjeet Kalara, another Clemson plant and environmental sciences graduate student, and Meghnaa Tallapragda, a former Clemson employee who is now a social scientist and assistant professor at Temple University.
Funding for this project is part of a $16.2 million investment from the United States Department of Agriculture National Institute of Food and Agriculture’s Innovative Plant Breeding Research program. This program supports research that involves innovations in agricultural production to help produce more food with less impact on the environment.