New research finds that fungi that live in healthy plants are sensitive to climate change

Spruce, pine, fir, and other trees tower over the cool patches of land that stretch across North America, northern Europe, and Russia in a great ring across the globe. These boreal forests form the largest terrestrial ecosystem on Earth and the northernmost forests.

Nestled within the photosynthetic, or light-eating, tissues of boreal trees—and between them are fungi within the cloud-like lichens and feathery mosses that carpet the land. These fungi are endophytes, meaning they live inside plants, often in a mutually beneficial arrangement.

“To be a plant is to live in a fungal world,” said Betsy Arnold, a professor in the School of Plant Sciences in the College of Agriculture, Life and Environmental Sciences and a professor in the Department of Ecology and Evolutionary Biology in the College of Science and Evolutionary Biology. A member of the Bio5 Institute. “Endophytic fungi are critical to plant health in ways that are not yet fully understood, but what we generally know from endophytes is that they protect plants from disease and “They’re great at helping us become more resilient to environmental stresses. Like heat. They’ve been part of a major revolution in how we think about plants.”

A decade ago, Arnold and his team embarked on a month-long adventure in the wilderness of northeastern Canada to understand how these fungal species adapt to different microenvironments and what they might do under future climate change. Can be beneficial.

They found great diversity among fungi and that they were adapted to their local conditions in very specific ways, indicating that they would be sensitive to changes in climate. Since the health of fungi is closely linked to the health of their hosts, these findings have implications for future overall health. Boreal forests And for our planet.

Boreal forests are central to our planet’s carbon and water cycles, Arnold said. “And our work highlights that they are home to some of the most evolutionarily diverse fungal endophytes in the world—endophytes that are found nowhere else.”

After more than a decade of analysis, they had results published In the journal Current biology.

“Our joint study sheds light on the diversity of newly discovered endophytic fungi in the boreal biome and their sensitivity to climate,” said study co-lead author Shuzo Oita, who did doctoral studies in Arnold’s lab. completed and is now a research scientist at Sumitomo. Chemical Company, Ltd. “Endophytes are often overlooked because they are found in healthy plant tissues, but their importance in biodiversity and ecosystems has only recently been revealed.”

Flight for Fungus

Gathering the data to reach this conclusion was a major effort that required Arnold and his colleagues to do the most intense fieldwork of their lives, he said.

For a month during the summer of 2011, the team contracted with an expert pilot to “access places where roads don’t go,” Arnold said. The six-person team traveled through Canada’s southern boreal forests to the edge of the arctic tundra, landing their floatplane in lakes along the way.

Thirty-six times they flew and landed among the distant lakes that dot the landscape. Typically, they spent about six to 24 hours at each sampling site.

During the day, they collected healthy spruce tree leaves and fresh moss and lichens from the ground, putting their scientific treasures into zip-lock bags as they went. They also drilled tree rings, hoping to reveal their past, such as their age and exposure to wildfires. They also measured different forest properties to understand how plants varied across the landscape.

By night, as the northern lights fluttered overhead, they processed their samples in portable laboratories inside the pilots’ quarters. They sterilize fresh tissues to prepare them for DNA extraction and isolate fungal cultures to visualize and document the strains living in their samples.

“We would often work until 2 or 3 in the morning and sleep for a few hours before moving on to the next site,” Arnold said. The long days paid off: “In the fungal world, an hour of fieldwork is a year of characterization and a decade of potential analysis. And in just a few weeks, we covered a lot of ground.”

As they traveled from the warmer southern regions to the colder north, they repeated their patterns at intervals of about 100 miles. They also sampled along a band of latitude that was just as wide but represented much less change in climate, Arnold said.

They strategically modeled across these two dimensions to ensure that any differences in fungal biodiversity were indeed due to environmental differences rather than distance alone. Together, they covered nearly 1,500 miles in the De Havilland Otter that was their mobile home, often sharing their travel space with extra tanks of fuel.

Older studies have examined the correlation between biodiversity and latitude, which is often used as a proxy for climate. These studies found that, in general, life becomes more diverse near the equator, Arnold said. For example, for many groups of organisms, those in tropical rainforests have greater biodiversity than those in arctic tundra.

It turns out, it’s not that simple when it comes to fungi in the boreal zone.

“We show that boreal fungal communities do not necessarily change with climate in the same way as plant communities. Fungal species and host,” said co-lead author Jana Yu Ren, who completed her doctoral work and conducted laboratory analysis for the project as a postdoctoral scientist with Arnold before moving to Washington State University. “This means that We need to protect plants. and their fungal endophytes in the boreal biome, not just in one place, or we risk losing important biodiversity and protective fungi in these important forests.”

Arnold believes that the particular climate dependence of these fungal endophytes reflects a process of co-evolution with their hosts — or “research and development,” as he puts it — as plants find ideal endophyte partners. And plants thrive despite specific stresses. In these harsh northern landscapes.

“Endophytes are found all over the world, but are isolated in different environments. We think that endophytes are associated, in part, with how plants cope with environmental challenges on a global scale—that is, with their internal fungi. With partners,” said Arnold.

“There is not much information about an individual. Endophyte Does for individual plant. So, our study is fundamental in that we tried to find out who these endophytes are, and how they are distributed, and how they might change with a changing climate.”

She hopes future research can build on her findings.

“What we do know is that we’re losing that biodiversity when those forests are changing, and we still don’t know what the key drivers are,” he said.

Collaborator Francois Lotzoni, a professor of biology at Duke University and co-architect of the study with Arnold, agreed.

“It was some of the most complex fieldwork I’ve ever done, but it was one of the most exciting research experiences I’ve ever had,” Lotzoni said.

“Research is essential to document biodiversity in our changing world. The specimens we collect are deposited in herbaria and therefore have lasting value for understanding how species, their distribution , their genes and the ecosystems they inhabit change over time. In turn, the best way. Herbaria are being integrated with research labs at world-class universities to serve the scientific community.”

Within this mindset, Arnold is now working to use homegrown Arizona endophytes to increase crop resilience in this changing world.

“Just as boreal forests have an unexpected diversity of endophytes, so do plants in Arizona,” Arnold said. “Our next steps are to use these rich and ancient endophytes as tools to help plant growth. Ultimately, we hope that by understanding these fungi on a global scale, we can understand one of the most important aspects of our planet’s biodiversity. Not only can we chart the past and future of the element, but we can also use it to help crops in our local areas thrive with limited water and rising temperatures. You could say the future is fungal. “

Other co-authors are Jolanta Miadlikowska from Duke University, Bernard Ball from University College Dublin and Duke University, Ignazio Carbone from North Carolina State University, Georgiana May from the University of Minnesota, Nopaka B. Zimmerman from the University of San Francisco, Dansville. from the University of Florida and Valerie Truitt from the University of Arizona Laboratory of Tree Ring Research.