New study finds that some lichens are a foursome rather than a twosome.

That humble little lichen on your local tree might be a quartet of creatures instead of a duo, a new University of Alberta study suggests.

Former University of Alberta student Veera Tuovinen published a study this week in Current Biology on how wolf lichens are actually a partnership between four separate organisms – one alga and three fungi – rather than two as long assumed.

Lichen are those tiny colourful plant-like creatures you often find growing on your local tree, said U of A professor Toby Spribille, a co-author on the study. Symbiotic fusions between algae and fungi, these organisms create spectacular colours and structures their members cannot make on their own, which makes them of great interest to nanotechnologists.

While most people ignore them, lichen are an important food source for animals such as caribou and have great ecological value as absorbers of water, carbon and nitrogen, said Diane Haughland, lichen taxonomist at the Royal Alberta Museum. They’re also very responsive to air pollution and can be used to track air quality. Look at any local tree and you’ll find scores of them in the shape of hammered shields, pixie cups, shrubs and others.

For much of the last 150 years, biologists thought lichens were partnerships between one fungus and one alga, Spribille said. In 2016, his team used DNA analysis to discover that many lichen actually involve at least three creatures working in concert (two fungi and an alga).

During that study, Spribille said the team noticed a third fungus kept turning up in their samples of wolf lichens. (Wolf lichens are commonly found on conifers in the Rockies and sequoias in Yosemite National Park and look like Einstein’s hair dyed bright chartreuse yellow.) Tuovinen decided to investigate this mystery for her PhD, which she finished at Sweden’s Uppsala University.

Tuovinen and her team used lasers, microscopes, fluorescent dyes and DNA analysis to study about 809 wolf lichen samples from North America, Europe, Africa and Asia. Not only did they find this third fungus in 95 per cent of the lichens, but it also looked to be living symbiotically with the lichen’s alga.

“It seems to be playing nice, which was quite surprising,” Spribille said, as on its own this fungus is known as the parasitic witch’s butter mushroom.

Wolf lichens are some of the most intensively studied lichens in the world, which begs the question of how researchers missed this third fungus up until now.

Most researchers study lichen using regular light, under which fungi look like an indistinguishable mess of pale spaghetti, Spribille said. By using laser-activated fluorescent dyes, Tuovinen and her team were able to tell different species apart.

DNA analysis has also improved, he continued. In the past, researchers would deploy markers to detect specific DNA strands they thought might be in a sample – the equivalent of walking into a dark room and asking if Bob is there. Modern technology lets researchers simply sequence all the DNA in a sample to detect everything at once – they can now turn the light on to see that Bob, Jill and 20 others are there.

Haughland, who was not involved in this study, said this research demonstrates the use of new research techniques (specifically fluorescent dyes) and the importance of following your curiosity. It also shows we don’t know nearly as much about lichen as we thought.

“We have to kind of rethink what we know about lichen.”

Spribille said he suspects there are other multi-partner lichens out there. His U of A team is now studying Edmonton-area lichens to figure out how these algae and fungi interact.