- August 18, 2026
- By Kimbra Cutlip
Researchers at the University of Maryland contributed to a major advance in the fight against a pest responsible for a 5% yearly reduction in the U.S. wheat yield as well as serious damage to other crops worldwide.
The team cloned a gene that makes wheat resistant to predation by Hessian fly larvae and demonstrated its direct interaction with a protein produced by the insect. The research, described in paper published Friday in the journal Science Advances, breaks through a longstanding barrier to understanding and engineering pest resistance in wheat.
“This is very exciting, because it is the first time anyone has been able to clone pest resistance genes in wheat and demonstrate the direct interaction between the gene and the specific insect pest protein it reacts with,” said study co-author Nidhi Rawat, an associate professor in the Department of Plant Science and Landscape Architecture (PSLA). The study was led by Subhashree Subramanyam of the U.S. Department of Agriculture and Purdue University and Bikram Gill at Kansas State University. It also included Associate Professor Vijay Tiwari of PSLA and researchers from several other institutions.
Hessian flies are tiny, mosquito-like insects that cause hundreds of millions of dollars in damage to cereal crops like wheat, barley and rye around the world. Unlike other pests that eat crops, Hessian fly larvae secrete chemicals through their saliva into plant cells, transforming the cells into abnormal growths that feed fly larvae while robbing plants of nutrients.
Wheat has several genes that help the plant defend against the chemicals in Hessian fly larva saliva, but in 50 years of trying, scientists until now had not been able to demonstrate how those genes interact with the proteins in larvae saliva and trigger an immune response. Rawat and her colleagues developed new genomic tools to pinpoint the location of the Hessian fly resistance gene H13 and successfully grow wheat cultures with an over-expression of the gene in the laboratory.
When H13 detects a specific protein in larval saliva, the gene tells nearby cells to die off and surrounding cells to reinforce their walls, making them harder to penetrate. H13 also causes the wheat cells to produce molecules that are toxic to the larvae. This action cuts off access to the nutritious fluids and tissues in a plant, starving and poisoning the larvae.
After isolating the gene and creating H13-amped-up wheat cultures, Rawat and the research team were able to demonstrate the activation of H13 by a specific protein in the fly larva, validating the molecular mechanism that enables wheat to resist Hessian fly attacks.