Fungi are having a moment. The 2021 Netflix documentary “Fantastic Fungi” explores how fungi “literally hold our ecosystems together.” Studies of mushroom-based hallucinogens to treat post-traumatic stress disorder (PTSD) are underway across the globe. From books about trees “talking” to one another via their fungal relationships to a proliferation of Facebook groups for wild foragers—not to mention the mushroom motifs popping up on shower curtains, clothing and pillows—it’s hard to miss the giant wave of interest and enthusiasm for organisms that, traditionally, have been more ignored or feared than revered.
Scientists who study fungi in the Department of Botany scratch their heads over this trend. They’d like to think it’s at least partly a reflection of how discoveries in the field of mycology (“fungus science”) have highlighted the awesome interconnectivity of fungi within the diversity of life on Earth. But what they’ll also tell you is that we don’t know that much about fungi.
“Fungi are really the black box,” says Anne Pringle, who is the Mary Herman Rubinstein Professor of Botany and studies the ecology and evolution of fungi. “If you want to study a group of organisms that people do not understand very well, you turn to fungi.”
Mushrooms, as any forager can attest, are mysterious enough — what makes them pop up when they do? — but at least these macro-fungi are a little easier to spot than the micro-fungi, which include yeasts, rusts, mildews, spores and smuts. Growing inside substrates (even in the built environment), living inside us (or other animals), creeping along underground, fungi present little outward morphology that humans can easily interpret and understand. Nevertheless, they are hugely important and absolutely everywhere.
“You interact with them all the time,” says Pringle. “You may not know it, but if you use laundry detergent, the enzymes in that are derived from fungi. If you drink pop or beer, or eat bread, you are interacting with fungi.”
For Pringle and her students and colleagues, fungi present endlessly fascinating angles to study. The organisms—neither plant nor animal nor bacteria—occupy their own kingdom and play three key roles on Planet Earth: pathogens (commonly thought of as “bad” fungi, because they often kill their hosts), mutualists (living in association with plants, giving and receiving from them), and decomposers (occupying what Pringle calls “the least appreciated role”). All three types are studied here and not just within L&S. Our botany researchers collaborate with colleagues across campus, as well as with other institutions and groups across the nation and the world.
Here at UW, the Fungal Supergroup — a consortium of labs — meets monthly to talk about what’s happening in their areas. Along with Pringle and her Botany colleagues, those in attendance might include researchers from the School of Pharmacy’s new Transdisciplinary Center for Research in Psychoactive Substances, studying mushrooms’ active ingredient, psilocybin, in clinical trials to treat PTSD and depression. They might include medical mycologists from the School of Medicine and Public Health, who are working on treatments for fungal diseases in humans, as well as plant pathologists from the College of Agriculture and Life Sciences who are studying the impact of fungi on crops.
“There are few places on the globe with the collection of expertise with fungi that we have here at UW-Madison,” says Pringle.
Sharing fungal research can be a race against the clock to track a pathogen’s impact on human or animal populations. For Savannah Gentry, a graduate student in the Pringle Lab who studies fungal disease in snakes, collaboration has helped her understand more about the particular fungus she studies. There’s an urgency to her work: Snake populations have been declining worldwide, and they are important as both predators and prey in the ecosystem. Gentry is authoring a paper with Jeff Lorch, a microbiologist at the U.S. Geological Survey National Wildlife Health Center in Madison, on the ability of snake fungal disease to “jump” to other species of reptiles and worked with the UW-Madison School of Veterinary Medicine to set up her experiments (which showed, concerningly, that yes, there can be “spillover” into other animal populations).
Gentry, who also gives talks to herpetology societies in the upper Midwest, says it’s invaluable for graduate students to have a range of conversations and outside perspectives.
“When you’re talking with the community, you get wonderful, fundamental questions that maybe you haven’t thought about in a while,” she says. “I really value the whole framework of the Wisconsin Idea—the intersectionality that bridges communities in the name of science.”
In 2018, Professor Pringle was named a National Geographic Explorer and became part of a group of groundbreaking scientists, conservationists, educators and storytellers supported in their work to “illuminate and protect the wonder of the world.” In this role, Pringle is working with Colombian collaborators to share the results of research with community partners in Bogotá, Colombia, where a “sustainable city” initiative that includes massive tree-planting is underway. Pringle is investigating whether newly planted trees need something called mycorrhizal biofertilizer in order to thrive. It’s a question that the landscaping and agricultural community often ignores, as practitioners get swept up in the “craze” for beneficial fungi.
“What people are doing is buying products from a garden store or agricultural company with no idea what’s in that package, saying, well, if fungi are doing all these amazing things in the environment, they must be able to do things for me, too,” she says.
In Bogotá, Pringle and her colleagues are challenging assumptions and applying what they already know to find the best solutions. “We’re asking, is this like sprinkling salt into the ocean—there’s already enough mycorrhizae in soil and you don’t need more? Or, if trees do need this to thrive, can we use local fungi, instead of buying commercial products with potentially invasive fungi?” she says.
When humans decide to love something, we often love it blindly and a little too much, without considering its role in the ecosystem. Such is the case with the edible golden oyster mushroom, non-native to Wisconsin but cultivated throughout the state. It’s escaped farms and taken over parks and woodlands. Pringle studies two problems created by the invasion: displacement (other species are getting pushed out) and disruption (the golden oyster may be disturbing carbon cycles in ways we don’t quite understand) and is collaborating with the Northern Research Station of the Forest Service here in Madison.
“It is such a pleasure to work with the Forest Service folks,” says Pringle. “They have a completely different perspective on forests and ecosystem dynamics.”
Another genus of mushroom is invading California. Often called toadstools, Amanita mushrooms can be stunning and sometimes quite toxic. Yen-Wen Wang (who goes by “Denny”), a graduate student in the Pringle Lab, studies two species of Amanita mushrooms: death caps and fly agarics. A single death cap mushroom can kill a person. Fly agarics, on the other hand, are hallucinogenic (they’re also cute and red, and featured everywhere in popular culture, from pillows to stationery to the Super Mario games).
Wang, who studies population genetics in fungi, says he was drawn to UW-Madison because of the rich history of scholarship in these areas. He points to UW geneticists James Crow and Sewall Wright, as well as Kenneth Raper, a microbiologist and mycologist who pioneered the study of a cellular slime mold, as key figures who laid important groundwork.
“There is no doubt that the success of these biologists established the status of UW-Madison in these areas, and this continues to attract more students and faculty to work here,” he says.
UW has been documenting fungal and lichen biodiversity all the way back to the mid-1800s, and nowhere is this more evident than at the Wisconsin State Herbarium, housed on the lowest level of Birge Hall. The herbarium is the repository of one of the largest lichen collections in the western hemisphere (lichens are a symbiosis of fungi and algae), according to director and botany professor Ken Cameron (who is also a world-renowned expert on orchids).
“Lichens are often thought to be a ‘canary in the coal mine’ when it comes to detecting air pollution and climate change,” says Cameron. “Our collections are getting a lot of attention, and we loan them out to institutions and scientists around the world.”
The herbarium also has the second-largest collection of micro-fungi in the world. In 2016, staff discovered something unexpected: examples of fungi collected by George Washington Carver.
The prominent botanist, who had been born a slave and rose to lead the agricultural department at Alabama’s Tuskegee Institute for 47 years, collected specimens of fungi that infect plants, and he shared at least 59 of them with the botany department at UW-Madison.
In the 1960s, the herbarium gave away its entire collection of macro-fungi to the Field Museum in Chicago, so there are no mushrooms on hand, but has doubled down on its preservation and sharing of micro-fungi. Multiple grants from the National Science Foundation have enabled the herbarium to create a digital database of its collection.
“Like libraries and bookstores, we feared that digitizing everything would mean people would never come look at actual items anymore,” says Cameron. “But we’ve seen the opposite—the more information we make available digitally, the more people want to come and see it.”
Cameron, though not a mycologist by training, encounters fungi in his work since orchids (his specialty) can’t survive without them. That includes the coral root orchid, a Wisconsin native so dependent on fungi that it can’t make chlorophyll.
“If you want to epitomize the fragility of the web of life, you just have to look at the orchid,” Cameron says. “It needs a certain insect to pollinate it, a fungus to feed it, the fungus itself needs a healthy clean ecosystem—you break one link and this whole thing collapses.”
Mycologists are working with soil scientists, microbiologists, farmers and others in the agricultural realm to understand the full scope of the role fungi play in the ecosystem. For generations, growers have battled fungal “scourges” with a variety of measures (some harmful). The economic impact of fungi on a crop can be significant. Cameron points to a 1912 federal ban on growing currants to prevent the spread of white pine blister rust (which flourished on currants, a willing host). It’s legal to grow currants again in Wisconsin, but our state’s hop industry—once leading the country—took a hit from downy mildew in the 1920s, and production moved to the West Coast. There’s evidence that hops are making a comeback, though. A better understanding of fungi and fungal relationships can only benefit future efforts to grow crops, treat diseases in animals and people, and understand our own dependence on a kingdom so mysterious, yet so essential to life.
