Wheat gene for Hessian fly resistance cloned after 50-year search

Researchers at the University of Maryland and collaborators have cloned the wheat gene H13, which confers resistance to Hessian fly larvae, and demonstrated its direct interaction with a specific protein in the insect's saliva. The findings were published August 14, 2026, in the journal Science Advances.

Hessian flies are small, mosquito-like insects whose larvae secrete chemicals into wheat cells, transforming them into abnormal growths that feed the larvae while depriving the plant of nutrients. The pest causes hundreds of millions of dollars in damage globally and reduces U.S. wheat yields by roughly 5% annually.

For 50 years, scientists knew that wheat possessed genetic resistance to the fly but could not isolate the responsible genes or show how they interact with larval saliva proteins. The wheat genome's size and repetitive sequences made cloning individual resistance genes extremely difficult.

The team developed new genomic tools to pinpoint the location of H13 and created wheat cultures that overexpress the gene. When H13 detects a specific protein in larval saliva, it triggers nearby plant cells to die and surrounding cells to reinforce their walls, while also producing molecules toxic to the larvae.

This response cuts off the larvae's access to nutritious plant fluids and tissues, effectively starving and poisoning them. The researchers validated this molecular mechanism by demonstrating H13 activation by the specific salivary protein in their laboratory cultures.

The breakthrough enables researchers to begin developing gene-based solutions for a persistent agricultural pest that affects wheat growers worldwide. The study was led by Subhashree Subramanyam with Nidhi Rawat, associate professor of plant science at UMD, as a co-author.