Scientists from the USDA's Agricultural Research Service (ARS) have made significant progress in combating Fusarium head blight, a dangerous disease that affects wheat and other cereal crops worldwide.
Farmers need to be vigilant and recognize the signs of Fusarium head blight, a grain disease that thrives in high humidity and warmth. This disease, caused by the fungus Fusarium graminearum, leads to significant crop losses of wheat and barley totaling over $1 billion annually. Additionally, the fungus produces mycotoxins that can contaminate grain, making it unsuitable for consumption as food or feed.
The new method has allowed to break the situation with Fusarium head blight, potentially reducing the health risks for people, farmers' incomes, and the U.S. wheat export market valued at $5.94 billion.
The discovery of the group, published in the journal Molecular Plant-Microbe Interactions, focuses on a key molecule naturally produced by the fungus known as FgTPP1.
Matthew Helm, group leader and molecular biologist at the ARS Plant Science Research Unit in West Lafayette, Indiana, explained: "This molecule helps the fungus break down the plant's defense mechanisms or weaken them enough to provide an opportunity for reproduction in the rest of the plant."
FgTPP1 is one of the many molecules that the fungus uses to infect wheat plants and cause Fusarium head blight. The fact that other Fusarium species also produce FgTPP1 "suggests that it plays an important role," added Helm.
To test this hypothesis, researchers applied a standard procedure to remove the FgTPP1 gene from the fungus. Then, in laboratory conditions, they infected the heads of sensitive hybrid wheat plants with the fungus lacking the gene. They also infected a second group of wheat heads with the fungus containing FgTPP1. This allowed scientists to compare the development of Fusarium head blight in wheat heads exposed to two types of fungi.
As expected, wheat heads exposed to the fungus lacking the gene fared better against the pathogen compared to those infected with the intact fungus: the former led to disease in 18–27% of wheat heads, while the latter affected 50%.
Thus, researchers demonstrated that during infection, the fungus uses FgTPP1 to disable the plant's defense response, facilitating its spread and the occurrence of Fusarium head blight.
Helm's team is now studying which wheat proteins are key targets for FgTPP1 and whether it is possible to slow the spread of the fungus throughout the plant by removing them.
"Most importantly," emphasized Helm, "is to avoid harm to the plant by removing a protein that is also important to it."
The research results will be valuable for commercial wheat cultivation, which, thanks to this approach, naturally resists the disease and prevents mycotoxins from contaminating the grain intended for consumers and livestock. Ultimately, the implementation and study of new methods, similar to this one, "add another solution to the arsenal of tools that American farmers can use to combat Fusarium head blight in wheat and possibly barley," Helm concluded.
