Microbiology Resource of the Month: Microvirus Genomes Found in Gila Monster Feces

May 26, 2021

Announcement: Genome Sequences of Microviruses Identified in Gila Monster Feces

Resource: 33 Unique Microvirus Genomes

Model structure of phi X 174, a bacteriophage belonging to the Microviridae family.
Model structure of phi X 174, a bacteriophage belonging to the Microviridae family.
Source: wikimedia.org
Microviruses are single-stranded DNA bacteriophages that, as the name implies, are amongst the smallest DNA viruses identified to date. These tiny microbes exist in a variety of environments and are known to infect a wide range of bacterial hosts, including Bdellovibrio spp., a predatory bacterium found in freshwater, estuarine and marine habitats, and various species of enterobacteria, usually found in animal gut samples.

Recently, a team of scientists published the genomes of 33 microviruses that were isolated from a unique source: Gila monster feces. Little is known about the viruses that infect the heavy, slow moving venomous lizards of the North American Sonoran Desert, so Arvind Varsani, Ph.D., Associate Professor of the Biodesign Center for Fundamental and Applied Microbiomics, and his colleagues at Arizona State University set out to further investigate the reptile’s viral diversity. We asked Varsani about his team’s discovery.

What are microviruses and where are they typically found?

Varsani: Microviridae is a family of bacteriophages that have single-stranded DNA genomes, small, icosahedral capsids and 2 classified subfamilies, Gokushovirinae and Bullavirinae.

Based on the few microviruses that have been cultured and studied, we know that they infect enterobacteria (usually gut bacteria), and thus they can be abundant in fecal samples.

From where did you isolate these particular microvirus sequences?

Varsani: We identified these viruses in the fecal samples of 14 individual Arizona-dwelling Gila monsters in 2016. It is therefore likely that they infect the gut bacteria of Gila monsters.

What makes the Gila Monster a unique host for these microbes?

Gila monster
Photo of a Gila monster, a large species of venomous lizard native to the southwestern United States and northwestern Mexican state of Sonora.
Source: fws.gov
Varsani: We were initially trying to identify what would be infecting Gila monsters, but we ended up finding these viruses that likely infect bacteria in the gut of the animals. Nonetheless, we know very little about viruses infecting Gila monsters, and that knowledge gap is what prompted our discovery study.

How will you use these genomes in your future research?

Varsani: These genomes will be analyzed within a broader context of all microviruses to understand their diversity, distribution and evolution.

How will other scientists in the research community use this resource?

Varsani: This resource adds new sequence data with a source and geographic location. This resource can be incorporated into larger studies to address diversity, distribution and evolution of microviruses, as well as their association to gut flora of animals.

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Author: Ashley Hagen, M.S.

Ashley Hagen, M.S.
Ashley Hagen, M.S. is the Scientific and Digital Editor for the American Society for Microbiology and host of ASM's Microbial Minutes.