How leafcutter ants cultivate a fungal garden to degrade plants and provide insights into future biofuels

Read the full story from Pacific Northwest National Laboratory.

Scientists have spent decades finding ways to efficiently and affordably degrade plant materials so that they can be converted into useful bioproducts that benefit everyday life. 

Bio-based fuels, detergents, nutritional supplements, and even plastics are the result of this work. And while scientists have found ways to degrade plants to the extent needed to produce a range of products, certain polymers such as lignin, which is a primary ingredient in the cell wall of plants, remain incredibly difficult to affordably break down without adding pollutants back into the environment. These polymers can be left behind as waste products with no further use. 

A specialized microbial community composed of fungus, leafcutter ants, and bacteria is known to naturally degrade plants, turning them into nutrients and other components that are absorbed and used by surrounding organisms and systems. But identifying all components and biochemical reactions needed for the process remained a significant challenge—until now. 

As part of her Department of Energy (DOE) Early Career award, Kristin Burnum-Johnson, science group leader for Functional and Systems Biology at Pacific Northwest National Laboratory (PNNL), and a team of fellow PNNL researchers, developed an imaging method called metabolome informed proteome imaging (MIPI). This method allows scientists to peer deep down to the molecular level and view exactly what base components are part of the plant degradation process, as well as what, when, and where important biochemical reactions occur that make it possible. 

Using this method, the team revealed important metabolites and enzymes that spur different biochemical reactions that are vital in the degradation process. They also revealed the purpose of resident bacteria in the system—which is to make the process even more efficient. These insights can be applied to future biofuels and bioproducts development. 

The team’s research was recently published in Nature Chemical Biology.