Smut Fighters Tackle ‘Rot’
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Michael Perlin looks at a lot of smut.
He even likes to eat it.
But don’t get the wrong idea.
Ustilago maydis, also known as corn smut, is a fungus that causes hundreds of millions of dollars in losses to the United States corn crop annually. Also known as the Mexican truffle, the black bulbous fungus is considered a delicacy.
“It’s sort of like a crunchy mushroom with a smoky flavor,” says Perlin, a U of L biology professor.
Eating corn smut is safe, yet the processes leading to such fungal diseases can be dangerous to agriculture and people.
Perlin and his research colleagues want to better understand how corn smut and other fungi develop, invade and take over a host organism.
“Fungi exhibit dimorphism,” Perlin explains. “That is, they can grow in a yeast-like, single-celled form or they can switch to a fuzzy filamentous form. That’s important because a lot of organisms that cause disease change from a yeast-like phase to a filamentous phase.”
Once inside a human host, for instance, fungal organisms can switch to a dangerous form inside the bloodstream or the digestive tract and cause infections. People with weakened immune systems, including those with AIDS or patients undergoing chemotherapy, are susceptible to wild yeast-borne fungal diseases such as Candida albicans.
Perlin’s research team uses bread yeast as the basic model system to understand how many fungal systems work.
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Biology professor Michael Perlin, above cetner, works with students to study how corn smut and other fungi invade organisms.
“Yeast is a well-understood, well-characterized model system,” Perlin says. “The signaling pathways used by plant pathogens such as corn smut are the same ones used by yeast to make the switch from one form to another.”
Perlin’s young biology colleagues Zhanyang Yu, a Fellow and teaching assistant, and Ben Lovely, a master’s degree student, are trying to disrupt the signaling pathways in yeast. By altering genes, disrupting proteins and causing other havoc inside the yeast cell the researchers want to find the key components leading to the dimorphic switch.
“It’s important to know how these pathogen pathways work, the whole nine yards,” Lovely says.
“Our hypothesis has been that this dimorphic switch is an absolute requirement for causing disease,” Perlin says.
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Biology Fellow Zhanyang Yu grows an ustilago maydis sample to study gene expression in fungi.
Ironically, the smut fighters are finding that mating may play a key role in fungal pathogens to make the dimorphic switch.
“Mating is one reason for a fungal system to become filamentous,” Perlin says. “In the fungal system, a pheromone is secreted during mating. The receptor for that pheromone basically says, ‘Hey, I’m here.’ A receptor for that pheromone acts on the signal. They come together and fuse, and filamentous growth results.”
With more findings, Perlin says that more research funding should follow.
“The university has been generous with start-up monies for this work,” he says. “I think we’re ready for the next phase, to seek NIH (National Institutes of Health), NSF (National Science Foundation) and USDA (U.S. Department of Agriculture) funding.”
Lovely agrees, adding, “What we’re doing has economic importance for farmers and importance for everybody’s health—just from looking at corn fungus.”
