CUR - The Council on Undergraduate Research

The Characterization of the Microbiome for the Northern Two-lined Salamander (Eurycea bislineata) and Its Ecological Interactions with the Pathogen Batrachochytrium dendrobatidis

Kristen Enns, Matthew H. Becker PhD Department of Biology and Chemistry, Liberty University, 1971 University Blvd. Lynchburg, VA 24515

Fungal pathogens are a major threat to amphibians worldwide, but the most prevalent fungal pathogen is Batrachochytrium dendrobatidis (Bd). Bd is a chytrid fungus that is highly virulent and has been linked to population decline in numerous amphibian populations across the world due to the development of chytridiomycosis. Bd infects the amphibian’s skin by rooting their spherical thalli into the amphibian’s keratinized epidermal layer of their skin, disrupting the exchange of many vital molecules such as oxygen, carbon dioxide, and ions. The focus of this project was to characterize the skin microbiome of the Northern two-lined salamander. The resident microbiome of an individual is intricately linked to its survival and overall health due to its role in metabolism, the immune system, and in defense. It has been demonstrated that the microbiome plays a vital role in pathogen-host interactions, so it is vital to better understand the role that the microbiome plays when it comes to preventing pathogens, such as Bd. This project focused on describing the microbiome of the Northern two-lined salamander by collecting swabs from individuals caught along the Blue Ridge Parkway. All bacterial samples were isolated on R2A media and the 16S rRNA gene was extracted using a freeze-thaw technique. Once the DNA was extracted, a PCR was run, and samples were sent off for sequencing. We are currently, using sequences to identify each unique morphotype that was cultured on R2A. The hope is that this project is to act as springboard for future work when bacterial isolates can be used in a challenge assay against Bd in hopes of finding bacterial strains that inhibit the fungal pathogen.

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