Corn smut

Corn Smut

Ustilago maydis diploid teleospores under 160X magnification.

Corn smut is a plant disease caused by the pathogenic fungus Ustilago maydis. This fungus infects maize (corn) and is known for producing large, tumor-like galls on the ears, leaves, and stalks of the plant. While considered a pest in some agricultural contexts, corn smut is also a delicacy in Mexican cuisine, where it is known as huitlacoche.

Biology

Ustilago maydis on a corn plant.

Ustilago maydis is a basidiomycete fungus that undergoes a complex life cycle involving both haploid and diploid stages. The fungus produces haploid sporidia that can germinate and infect corn plants. Upon infection, the fungus induces the formation of galls, which are filled with diploid teleospores. These teleospores are released when the galls mature and rupture, allowing the fungus to spread to new hosts.

Infection Process

The infection process begins when the haploid sporidia land on a susceptible corn plant. The sporidia germinate and form hyphae that penetrate the plant tissues. Once inside, the fungus manipulates the plant's cellular machinery to form galls. These galls can appear on any above-ground part of the plant, including the ears, where they are most commonly observed.

Economic Impact

Corn smut on an infected ear of corn.

In agricultural settings, corn smut is often considered a pest due to its potential to reduce crop yields. However, in regions where huitlacoche is harvested and sold as a food product, the presence of corn smut can be economically beneficial. The fungus is deliberately cultivated in some areas to produce huitlacoche for culinary use.

Culinary Use

Huitlacoche for sale in Oaxaca, Mexico.

In Mexican cuisine, huitlacoche is a prized ingredient, often referred to as the "Mexican truffle." It is used in a variety of dishes, including tacos, quesadillas, and soups. The flavor of huitlacoche is earthy and mushroom-like, with a hint of sweetness.

Popular Dishes

A taco filled with huitlacoche.

• Tacos de Huitlacoche: Soft corn tortillas filled with sautéed huitlacoche, often accompanied by cheese and salsa.

• Quesadillas de Huitlacoche: Quesadillas filled with huitlacoche and Oaxaca cheese, grilled until the cheese is melted and the tortilla is crispy.

A quesadilla de huitlacoche.

Related Pages

• Maize
• Fungal plant pathogens
• Mexican cuisine