Fungus That Tastes Just Right: PNNL Researchers Study Plant Material in Soils that Offers Clues for Making Sustainable Bioproducts

by Allan Brettman (Pacific Northwest National Laboratory) Discerning leaf-cutter ants know what food they like to eat. They turn up their scent-detecting antennae at some plant material in soils in favor of others that fungus has degraded just the way they like it. That’s partly because the ants helped cultivate the fungi and, in true farmer-like fashion, they know where the fungus holds its nutrients.

In an ongoing study, Pacific Northwest National Laboratory (PNNL) researchers are forming a clearer picture of how plant matter is transformed in the microbial gardens the ants create.

“We’re starting to really unravel the complexity of the fungal garden ecosystem,” said Kristin Burnum-Johnson , a PNNL bioanalytical chemist in the Earth and Biological Sciences Directorate. “We’re looking at this ecosystem on a microscale, studying how it can degrade this plant material so efficiently. You have a very complex system with multiple layers. The only way we can truly understand how it works is homing in and understanding how things are happening at each level—where the activity is.”

In the latest of three studies of these softball-sized garden ecosystems, Burnum-Johnson’s research team focused on lipids that are present in the leaf-cutter ants’ cultivated fungus—called Leucoagaricus gongylophorus. The work stems from Burnum-Johnson’s selection to receive a U.S. Department of Energy (DOE) 2019 Early Career Research Program award in which she embarked on exploring how leaf-cutter ants take advantage of such microbial communities by maintaining fungal gardens that release useful metabolites from plant biomass.

This detailed understanding of how fungus degrades biomass could one day help scientists develop microbial systems for sustainable bioproduct production, such as biofuels or renewable chemicals. READ MORE