The secret life of mushrooms

What can be deadly poisonous but taste great on pizza? What creature can have as much mass as several dozen blue whales, but hide in the back corner of a minibar? The answer: the mushroom. Mushrooms are diverse and mysterious creatures. More than that, they are pillars of our ecosystem. Without fungi, our planet would be a different place.

Dr. Ewald Langer is a professor at the Department of Ecology. He deals with mycology, the study of fungi. "The subject of fungi seems uninteresting to many at first glance," Langer says. "But most go wide-eyed when you explain where they encounter fungi every day."

From A for antibiotics to Z for lemon juice.

Mushrooms are everywhere. They're not just in our environment, they live in us and on us. "As we sit and converse, we breathe in fungal spores," Langer said. Most of the time, they don't harm us in the process. However, there are counterexamples: "Athlete's foot, for example, is a parasite that many of us are familiar with," says the biologist. "Up to 25 percent of Germans suffer from it. In occupational groups that often wear rubber boots, it's up to 80 percent." But it is not only here that we encounter them.

Without mushrooms, many foods could not be produced. "The lemon juice from the supermarket has often never seen a lemon," Langer explains. "It is industrially produced by feeding the fungus Aspergillus niger. The waste product is lemon juice." Chemically, he says, this is the same as the juice from a lemon.

Other example: Yeasts are nothing other than fungi. In plain language, this means that without fungi there would be no beer or wine. But not only would we have to do without certain beverages, even basic foodstuffs would be more difficult to produce without mushrooms. In Central Europe, for example, yeast is usually used to bake bread.

The chemical and pharmaceutical industries also often depend on fungi. "The stain-removing active ingredients in detergents, for example, come from fungi," Langer says. Not only our clothes, but also our health profi ts. One of the most significant discoveries in modern medicine is antibiotics. In 1928, the Scottish physician Alexander Fleming discovered that a certain mold kills bacteria. Penicillin, the first antibiotic, was later produced from an active ingredient in this fungus. Even fungicides, called fungicides, are derived from fungi!

"The ecosystem would not function without them".

That's just the everyday benefits of fungi. In fact, they lay the foundation for life on Earth. "Our ecosystem wouldn't work without fungi," Langer says. "Even the landfall of plants in the Devonian age more than 358 million years ago would have been impossible without fungi." Some fungi are so-called saprophytes. They feed on dead organic material and often have parasitic properties. "Other fungi are what are called symbionts." They live in symbiosis with plants. Wherever there are trees, there are fungi. The two are interdependent. "Ultimately, it's a trade-off between plants and fungi," Langer explains. "The fungi get sugars from the
photosynthesis of the plants, and the plants get water and nutrients such as nitrogen in return." Without fungi, much of the plant life, which in turn is the basis of life for other living things, could not survive. As if that weren't amazing enough, they have even more to offer.

2400 years, 600 tons, one fungus

What many don't know: The largest known living thing in the world is a fungus. In 2000, U.S. researchers in Oregon were searching for the cause of forest dieback there. Climate change? No. A single fungus. A so-called Hallimasch had settled there and attacked the trees. How can that be? A single fungus puts a forest at risk? "The part of the fungus we can see, the one with the cap, that's just the fruiting body,"
explains Langer. "But fungi form huge systems, most of which run underground." Microscopically thin strands underground make up most of the living thing. Fungi are often gigantic networks. The Hallimasch in Oregon has spread over an area of more than 900 acres and weighs about 600 tons. All parts combined, it has the biomass of several dozen blue whales. It is the heaviest known creature in the world and the oldest: probably 2400 years old. When it was created, the Greek crisis was still understood as the war between Athens and Sparta.

Neither plants nor animals

This example alone shows that fungi are fascinating. It is no wonder that Professor Langer and his team are passionate about this subject. He explains the tasks of his department at the University of Kassel with great enthusiasm. "We close research gaps," says Langer. "It's real detective work." The department's staff researches ecology and describes new species of fungi. The work for this takes them around the world. For example, Prof. Langer has conducted research on the tropical island of La Réunion. Here there are numerous endemic fungi, species that only occur there. "We collect mushrooms and mushroom samples and generate genetic data sequences, so-called DNA barcodes," says the mycologist. "After that, we feed them into a public database."

Fungi are neither plants nor animals. "They form their own realm among living things," Langer says. About 110,000 species of fungi are known to researchers. "However, extrapolations suggest that there are five to six million species," he explains. Unlike plants, fungi have hardly been researched. "If you want to identify plants, you need a single book. With fungi, it's a whole shelf." Usable DNA sequences of just 25,000 fungal species have been deposited, he says. "There's still a lot to discover." The department also oversees the Kellerwald Edersee National Park. "The national park in northern Hesse has primeval forest qualities," Langer said. "There is a long deadwood tradition here, meaning a lot of very old dead wood." That could be seen, for example, in special fungi. The fungi there are typical of old dead wood, he said. "So the mushrooms tell us if we're dealing with a virgin forest-like forest." At the nature park, the department often organizes field trips with students. Langer is convinced outdoors is the best place to learn. "You remember names and characteristics of mushrooms better if you've seen and touched them." Another mission of the department is forest conservation. "We research the ecology of harmful fungi." For example, he said, ash trees and other tree species are endangered by a harmful fungus from China. "These harmful fungi are what we want to understand."

Are vegetarians allowed to eat pizza funghi?

Mushrooms have another special feature: they often taste very good. Prof. Dr. Langer is a mushroom collector himself and leads mushroom tours. "The curly hen, for example, is very tasty," says Langer. But the expert warns, "There are only about 400 edible mushrooms." Most others of the 6,000 known species of mushrooms in Germany are poisonous, he says. "Definitely don't go mushroom picking without someone who knows exactly what you're looking for."

One question remains: If mushrooms are neither plants nor animals, what exactly are we eating when they're on our plates? "What's interesting is that mushrooms are more closely related to animals than they are to plants." Mushrooms and animals? Would vegetarians then even be allowed to eat a pizza funghi? Prof. Langer gives the all-clear: "But of course! Mushrooms are ideal for vegetarian and vegan diets." Just one of the many amazing facts about them. Hats off to the mushroom.

By David Wüstehube

This article appeared in publik 4/2018 (Dec. 18, 2018).