Looking closer at the hidden diversity belowground

Adam Frew did not set out to become a fungal ecologist. During his PhD in Australia, he studied how plants interact with insect herbivores. Mycorrhizal fungi entered the picture because he wanted to know whether they could change a plant’s ability to defend itself against insects.

As he got deeper into the field, one question increasingly preoccupied him. Researchers were studying how mycorrhizal fungi affected plants, yet many experiments relied on the same handful of fungal species.

 “We knew that different fungi could have different effects, but we knew much less about what that diversity meant for plants,” Adam says.

And then my world changed.

At the time, he lacked the methods to study this diversity. A colleague suggested a research stay in Maarja Öpik’s lab in Tartu, Estonia, where there was strong expertise in identifying mycorrhizal fungi using molecular methods.

“And then my world changed,” he says.

The stay gave him the means to investigate which fungi were present and shifted the direction of his research. From then on, he increasingly focused on fungal communities: which fungi occur where, what shapes those communities, and how they affect the plants they associate with.

Fungi are part of the plant story

For Adam, the importance of mycorrhizal fungi extends far beyond their effects on individual plants. 

“Fungi helped make plants what they are today,” he says. “They allowed plants to come onto land half a billion years ago.”

Mycorrhizal fungi occur across many environments and can shape plant communities as well as nutrient and carbon cycling. Treating plants separately from their fungal partners can therefore leave researchers with only part of the picture. 

Fungi helped make plants what they are today.

“It is a bit like going into a forest and only measuring tree height and thinking you now have all the information you need to understand what is happening there,” Adam says.

As vegetation shifts and plants change their distributions, some trees may struggle in places where they previously thrived. To understand and predict those changes, Adam argues that researchers also need to consider the fungi the trees depend on.

“If we want to predict how things are going to change, or manage and look after these systems, then we need to understand that part as well,” he says.

Mapping fungal diversity in Sweden

One of the first questions Adam wants to explore at UPSC is which arbuscular mycorrhizal fungi are present in Sweden and what determines where they occur. He has been investigating similar questions in Australia, but northern Sweden offers a very different ecological setting.

“We have very little data, so there is a lot that is simply unknown,” he says. “I do not know what to expect, which makes it very exploratory but extremely cool.”

He is also moving into a new research direction: trees that can associate with two different types of mycorrhizal fungi. Arbuscular mycorrhizal fungi interact closely with cells inside plant roots, while ectomycorrhizal fungi grow around the outside of roots and are common among many forest trees in northern Europe.

Poplar, alder and willow can associate with both types. Such dual associations are relatively uncommon, and observations suggest these trees may cope particularly well with stressful environments. 

“I want to understand the relative importance of these two types of fungi for these trees,” he says. “That is quite a new direction for me, and I am really excited to explore it.”

Adam Frew wants to understand which mycorrhizal fungi occur in Sweden, what shapes their distribution and how they influence plants and ecosystems.

ImageMalin Grönborg

A fungal perspective on forests

After spending his research career in Australia, Adam had long been interested in working in Northern Europe. Previous stays in Finland and Estonia had introduced him to the research environment, and he already knew UPSC through colleagues and collaborators.

“People always spoke very positively about the environment here,” he says.

Adam was recruited to UPSC within the Wallenberg Initiatives in Forest Research, WIFORCE, which brings together research ranging from fundamental plant biology and ecology to forest management and the relationships between forests and people.

WIFORCE is trying to capture the whole picture - and fungi are an important part of that.

That broad perspective fits well with Adam’s research on mycorrhizal fungi.

“WIFORCE is trying to capture the whole picture,” he says. “And fungi are an important part of that.”

He hopes his group can contribute knowledge about the fungal communities associated with forests and how they influence plants and ecosystems. 

“It is kind of a privilege, but also a responsibility,” he says.

Building a culture of curiosity

For Adam, unanswered questions are part of what makes research exciting – and he wants to create a group where that curiosity drives the work.

“I love talking about science and looking at new findings together and asking: but what does that mean? We do not understand this yet.”

He also values the sense of community he has found at UPSC and enjoys life in Umeå, from its university atmosphere to the sharp contrast between winter and summer – extremes that he says he likes.

There is plenty he wants to explore, but he also knows that research does not always follow the path one expects.

“You may have an idea of where you want to go, and then it might shift. You have got to enjoy the ride.”