What are mycorrhizae, and why should we care?
Mycorrhizae are fungi that grow around the roots of plants. Mycorrhizae form large networks of thin, cotton-like filaments that spread throughout the soil around the plant, from the lowest parts of the roots, up to the soil surface.
A network of mycorrhizal fungi can break down organic matter, such as dry leaves, and even mine minerals in rocks. Mycorrhizae deliver water and essential nutrients directly to plants’ roots. In return, the plant roots provide sugary food to the fungi.
Adriana Corrales is a fungi ecologist and expedition leader at the Society for the Protection of Underground Networks (SPUN). SPUN is a nonprofit research organization that maps fungi worldwide.
Adriana explains the importance of mycorrhizae for plants: “The fungi form a microbiome [a community of microbes] on the plant’s roots in the same way that microbes in our gut help us digest food. We have these bacteria in our gut that break down the food we eat so we can absorb it. In this case, the fungi digest the food in the soil and bring the nutrients to the plant in exchange for sugar.”
Researchers at groups like SPUN are studying mycorrhizae around the world. Scientists have sequenced the genomes (genetic codes) of hundreds of mycorrhizal species, but none yet from from South America. And scientists are hard at work to change this.
Mycorrhizae research in South America
Adriana and her team are collecting mycorrhizal fungi samples in high-altitude forests in Colombia. Adriana has been studying fungi for 15 years, and she has found 20 species of fungi that have never been described by science.
“Oh, this one is so beautiful! Spectacular!” Adriana yells as she cuts a purple-capped mushroom, the size of her pinky finger, from the ground. Finding a mushroom indicates that there’s a whole unseen organism underground. “It looks like they are made of sugar candy,” she says.
When the experts find mushrooms, they first inspect them with the naked eye. Then they smell them. Some mushrooms of the Russulaceae family smell like fish, while others, like those of the genus Lactarius, have a hint of honey or maple syrup. Sometimes the researchers even bite off a little piece of the mushroom and then spit it out to avoid poisoning.
At night, back at their hotel bungalows in the jungle, they store their finds in plastic boxes out on the balcony. They then use a surgical knife to cut off a piece of each mushroom for detailed DNA analysis.
These samples are sent to labs in the U.S. to sequence their genomes. The complete genome can also reveal different characteristics of the species, such as their functions, what kinds of nutrients they obtain more effectively, and how they might interact with the trees around them.
Across South America, scientists are studying mycorrhizae in different habitats. In Argentina, Valeria Faggioli, a biologist at the National Agricultural Technology Institute, has been studying mycorrhizal fungi associated with the endangered monkey puzzle tree in remnants of the Atlantic Forest. In Chile, César Marín, a fungi ecologist at Santo Tomas University, is studying how fungi partner with the alerce tree, the largest tree species in South America.
David Brown adapted this story for Mongabay Kids. It is based on an article by Sofia Moutinho published on Mongabay News:
