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Alien Encounters

New faculty member Kathryn Bushley uses genomic analyses to study the curious characteristics of fungi.
 

Fungi are like aliens on Earth. Neither plant nor animal, they come in all shapes and sizes, from familiar mushrooms, to tangled threads, to slimy films. They make bread and beer possible, but they also cause diseases in animals and plants.

Kathryn Bushley loves fungi enough that she's devoted her career to studying them. Bushley joined the College of Biological Sciences this spring as part of a cluster hiring effort around fungal evolution. “[She] brings considerable intellectual and innovative capacity to the college,” says plant biology Professor George Weiblen,  who led the search. “She is a leader in the use of genomic analyses to address fundamental questions in fungal biology and evolution.”

Bushley's interests in fungi span a wide range of species. She's interested in the genome-scale evolution of fungal metabolism and the role that these metabolites play in interactions with other organisms. For her graduate work, Bushley studied the evolution of non-ribosomal peptide synthetases in Cochliobolus heterostrophus, the fungus that caused southern corn leaf blight and devastated U.S. corn crops in the early 1970s. Non-ribosomal peptide synthetases (NRPSs) allow fungi and bacteria to perform metabolic tricks that are impossible for plants and animals. Normally, living things use ribosomes to make proteins. Fungi can also make proteins using NRPSs, huge proteins that string together peptides without ribosomes and incorporate unusual amino acids, making lifesaving compounds like penicillin and cyclosporin possible.

Bushley plans to build on her graduate research on the evolution of NRPSs to analyze the evolution and regulation of fungal metabolite genes across fungi. She's actively expanding her lab, recruiting graduate students and post-doctoral researchers. She'd also like to move her research into the study of fungi that live on and inside plants, such as endophytes and beneficial root symbionts. Endophytes are fungi that infect plants without causing harm. Certain endophyte species can also infect insects. That's a surprising ability. Most infectious organisms have trouble crossing species, much less jumping from animals to plants. Bushley wants to know how these endophytic fungi got there. "I'm interested in the dual aspects of that ecology," she says.

Bushley caught the fungal bug while she was pursuing a master's degree in environmental science at Duke University. She had the opportunity to do a summer internship studying mycorrhizal fungi, fungi that live in a symbiotic relationship with plants' roots.

"I had never really encountered fungi before that," she says. When that fall, she took a course from Rytas Vilgalys, a prominent mycologist, her fate was sealed. "He turned me on to wanting to do this for a career," she says.

Since deciding to focus on fungi, Bushley has traveled half way around the world to study interesting species. Her new adventure here in Minnesota offers up something equally unusual: colleagues in the same department who study fungi, including another recent hire, Peter Kennedy. Bushley is excited to get to know her plant biologist colleagues as well. "I hope to add a perspective on how fungi may manipulate plants," she says. "Plants harbor an incredible diversity of microbes, and we're just beginning to understand what roles they play."

— Margaret Taylor

 

 

 


Far-flung findings

Busley spent a year in China investigating the evolution of Ophiocordyceps sinensis, an important fungus in traditional Chinese medicine. O. sinensis only grows high on the Tibetan Plateau and has been overharvested to the point that it's classified as an endangered species in China.

O. sinensis is a cousin to the fungus that makes “zombie ants” in the tropical rainforest. It forces infected burrowing moth larvae to point their heads upwards, then the fruiting body sprouts out of the head through the soil surface and releases spores.

At the time, nobody knew whether O. sinensis had to find a mate to reproduce, like animals, or could cross with itself, like many species of plants. Bushley found out through her work that it can cross with itself. That's good news for conservationists because it means that the fungus can keep reproducing even when individuals are rare and scattered far apart.