To help forests respond to a changing climate, WVU biologists are learning how bacteria and fungi in the soil sustain the health of forest ecosystems.
Fungi that have close symbiotic relationships with tree roots are called “mycorrhizae,” and Ember Morrissey, associate professor in the Department of Biology at the Eberly College of Arts and Sciences, is studying how two main types of mycorrhizal fungi interact with their host trees and other soil microorganisms.
All mycorrhizal fungi help trees absorb nutrients and water in exchange for carbon produced by the plants, but “arbuscular mycorrhizae” grow inside roots, Morrissey said, while “ectomycorrhizae” live on the root surface. Chanterelles and truffles are examples of mushrooms that sprout from ectomycorrhizal systems.
These two types of fungi are different in the ways they relate to their host trees, and Morrissey suspects they also differ in their relationships with soil microbes that break down organic forest matter like leaf litter and dead roots.
“We think these fungi are interacting in cooperative and competitive ways with microorganisms that decompose dead matter,” Morrissey said.
“For example, ectomycorrhizal fungi can release antimicrobial compounds that suppress rival microbes, reducing competition for nutrients. Many of the antibiotics humans use were first discovered in soil, born from this underground chemical warfare between competing microorganisms.”
Morrissey and Edward Brzostek, professor of biology, hope to determine how these microbial relationships happen and how they affect the movement of nutrients through the forest ecosystem.
The research is being carried out in three different arenas — in the lab, in a greenhouse and in the Fernow Experimental Forest.
“For the field component at Fernow, we’re going to study fully mature trees that associate with the two types of mycorrhizal fungi,” Morrissey said. “We’ll do some sampling of the ‘rhizosphere’ — the area of soil surrounding the tree root — and examine the microbes to see how the mycorrhizae influence the decomposition process.”
In the greenhouse, the team will grow trees and track how they transport nutrients through the mycorrhizae, while the lab will study the microbes’ DNA to understand what the organisms are eating and the production of carbon through the decomposition process.
“Predicting how an ecosystem will respond to change is very challenging, because we don’t know how all the pieces interact,” Morrissey said. “We’re trying to understand how environments will change in the future as some places get warmer and drier while others get warmer and wetter.”
The research team includes WVU undergraduate students, a doctoral student and a postdoctoral researcher. The research will also be incorporated in a citizen science day Morrissey and her colleagues host with fifth graders from a local elementary school.
Students from Morrissey’s newly launched WVU freshman biology class will also help advance the study as they learn fundamental research principles like formulating and testing hypotheses.
In fall 2025, the students isolated bacteria and fungi from tree roots. Using pure culture experiments, they can directly observe how different species of fungi inhibit bacterial growth, Morrissey said.
In the spring, they’ll extract and sequence microbial DNA to identify potential new species and study interactions between them.
A $1.1 million grant from the National Science Foundation supports the three-year study.
“This work should help us understand if the forest will function as a carbon sink or a carbon source in the future,” Morrissey said. “There could also be implications for forest management — like prioritizing oak regeneration if we find ectomycorrhizal systems will be storing more carbon.”