By Will Thompson, Earth Matter seasonal and Farm School apprentice (pictured in photo)
Although many farmers throughout the U.S. tremble at the thought of a corn smut (Ustilago maydis) infestation, this unique fungus is multifaceted and has many interesting and delicious uses. These fungal spores infect kernels of corn and suck energy from them to produce silvery, unsightly galls that are filled with resting spores, nick named smut. You may have seen relatives of corn smut in the basidiomycete fungi class while walking around Earth Matter such as mushrooms, puffballs, and stinkhorns, but unlike these others corn smut does not create fruiting bodies.
Considered an agricultural disease in the U.S., corn smut can cause crop loss ranging from 1-5% of a corn crop, so many farmers destroy infected crops and plant smut resistant strains. However, despite this there are some farmers that actually inject their corn crop with corn smut spores, hoping to cultivate the fungus as an edible delicacy. In Mexico and parts of the South Western U.S., where it is known as huitlacoche, the fungus is prized for its unique, earthy flavor and used in dishes much like a rare mushroom. In the Southwest, native groups such Navajo and Zuni have eaten Ustilago maydis for centuries and even used it for ceremonial and medicinal purposes. Only recently has corn smut broken in as an edible ingredient in high-end dinning in the U.S, now popping up on restaurant menus.
Corn smut husks
Another interesting use of corn smut is in biological research. When grown in a lab as a culture Ustilago maydis grows as an yeast that can easily be manipulated and used in experiments. Remarkably the corn smut genome is more closely related to humans than to other budding yeast, and so can be used as a model for experiments around human cell processes and functions. In fact, Ustilago maydis has been used in a number of important research findings in human biology such as studying mechanism of DNA repair, neuron transport, and cell division.
So while corn smut may not be winning any beauty contents, or gaining any love from some corn farmers, this interesting fungus has a lot to offer.