In a recent study published in Nature Communications, a team of researchers led by Byrd Center's ZhiPing Zhong has unveiled how viruses that infect microbes can potentially influence the cycling of methane, a critical greenhouse gas, through various ecosystems. By meticulously examining nearly a thousand metagenomic DNA datasets across 15 distinct environments—from the depths of diverse lakes to the guts of cows—the team discovered that these microbial viruses possess specialized genes, known as auxiliary metabolic genes (AMGs), which play a crucial role in regulating methane processes.

Zhong, a microbiologist focusing on the ecology and evolution of microbes in different settings, emphasizes the significance of understanding microbial dynamics in methane processes. Even though the microbial contribution to methane cycling has been studied extensively, the viral aspect remained largely unexplored. This research sheds light on this overlooked area and underscores the variability of viral impacts on methane cycling, contingent on their habitat.

Microbiology Professor Matthew Sullivan, Byrd Center principal investigator and co-author of the study, highlighted the omnipresence of viruses and their profound influence on ecological and biogeochemical cycles. He pointed out that their research enhances our understanding of metabolic genes encoded by viruses, demonstrating how these viruses significantly influence microbial metabolism during infection, particularly in the context of methane cycling.

This research comes at a time when the critical role of microbes in exacerbating atmospheric warming is acknowledged, yet the effect of viruses on these microbes' methane production remains a puzzle. The team has spent nearly a decade on sample collection and data analysis of the sediments of Vrana Lake in Croatia—a methane-rich environment within a protected nature reserve. Here, they discovered a rich diversity of viral communities and 13 types of AMGs that influence host metabolisms. However, no direct evidence was found that these lake-sediment viruses encode methane metabolism genes themselves.

The study illustrates that methane metabolism AMGs are predominantly found in host-associated environments, such as within the rumen —a fermentation chamber in the gut of certain mammals. These environments are known to contribute significantly to global methane emissions. This research suggests a complex interplay between viruses, living organisms, and their shared environments—potentially more interconnected than previously considered.

Zhong suggested that the worldwide effects of viruses could be undervalued, emphasizing the need for more comprehensive research in this area, hinting at the intricate relationship between viruses, climate change, and methane emissions.

Other co-authors of the study include Jingjie Du, formerly at Ohio State, Stephan Kostlbacher and Petra Pjevac from the University of Vienna, and Sandi Orlić from the Ruđer Bošković Institute.

The National Science Foundation, the Croatian Science Foundation, and the U.S. Department of Energy supported this research, marking a significant step toward understanding the impact of viruses and climate change.

Read about this study or download the PDF. 

Learn more by visiting Ohio State News.