The unknown world of fungi under our feet
5 October 2022
By taking soil samples and studying fungal DNA contained in them, Anna Rosling's research team is unearthing the diversity and distribution of a previously completely unknown group of fungi that they call ancient root fungi. In 2011, they were able to describe the first species of the group fungi after culturing it in the lab. But hundreds of uncultured species remain to be described.
“For instance, Russula fungi form a mycelium under the ground, where it spreads. There are lots of mycelia in the soil. But we cannot see the vast majority of fungi. They do not have a fruiting body, and that is what interests us,” says Anna Rosling, a researcher at the Department of Ecology and Genetics.
She and her colleagues take soil samples in order to find these invisible fungi. From these, they extract DNA sequences that they then compare with known fungi in reference databases.
“And then you suddenly come up with fungi that are not known anywhere. They have no known reference and are unknown to science. And in practice, this list is endless. Because only a fraction of them, between one and five per cent, have names, so the majority are these unknown fungi. There is a group of them, we are trying to sort them out and find out which ones they are,” says Anna Rosling.
Fairly common fungal group
Urrotssvampar means “ancient root fungi” and is the Swedish name that she and her research team have proposed to give to the fungi they have discovered.
“We and others had been seeing DNA from this group of fungi ever since DNA samples began to be taken from soil, and we can see it is a fairly common fungal group in many samples. In the first field study I ever did, we grew fungi from roots and were lucky enough to be able to culture one of these. I went out and took those samples back in 1999. And in 2011, we could describe it,” says Anna Rosling
This group of fungi, invisible to the naked eye, already existed in the era of the dinosaurs and can be found all over the world. There may be as many as 300 species in Sweden alone. But scientists still know very little about how they live and what their function is in nature.