Scientists block fungus gene to protect tomato crops

An international team of plant scientists has pinpointed the exact stretch of DNA in a soil-dwelling fungus that lets it weaponise a protein against crops. Led by Professor Bart Thomma at the University of Cologne, the group found the gene cluster inside Verticillium dahliae—the microbe behind verticillium wilt, a disease that strips leaves and stunts growth in tomatoes, potatoes and cotton. The breakthrough, published Monday in Nature Microbiology, shows how the fungus builds a syringe-like structure called a “mobile fungal starship” to inject a protein that makes plant cells collapse and drop off.

Verticillium wilt costs global agriculture hundreds of millions each year. The pathogen thrives in soil for a decade, waiting for roots to grow nearby. Once inside the plant, it deploys a cocktail of molecules; one of the most damaging is the protein VdAve1. The Cologne-led team used CRISPR gene editing to cut out the tiny section of the fungus’s genome that encodes VdAve1. When that chunk was missing, the microbe lost its ability to cause leaf loss in test plants. “We’ve literally disarmed the pathogen’s delivery system,” Thomma said.

The discovery matters because current control methods—long crop rotations and resistant varieties—are wearing thin. Some tomato growers still spray fungicides every two weeks, raising costs and resistance risks. The newly found gene cluster contains just 14 genes. Blocking any one of them stops the protein production entirely. Industry partners are already testing small-molecule inhibitors that target the cluster, aiming for a seed-treatment spray that would shut down the fungus before it even germinates.

Next steps include field trials in Europe and California to see if the inhibitors work under real conditions. If successful, farmers could swap heavy fungicide schedules for targeted sprays that only affect Verticillium. The research also opens a blueprint for fighting other wilts, such as fusarium, by identifying their own “mobile starships.” With climate change lengthening growing seasons and keeping soils warm, the clock is ticking on solutions that keep crops standing tall.