Amphibians play an important role in ecosystems all over the globe. However, they are being threatened by the rapid spread of a deadly wildlife disease caused by the fungus Batrachochytrium dendrobatidis (Bd). Many studies have shown that certain cutaneous bacteria provide a natural resistance against Bd, as a result of competitive interactions. However, we know little of the fungal diversity (beyond Bd) that exists on their skin and how those fungi interact with the disease and other cutaneous microbes. To fill this gap, we explored the culturable fungal diversity and function of the skin microbiome of the eastern redback salamander (Plethodon cinereus) at various sites in the New York City area. Individuals were swabbed and plated on two different types of media (PDA and MMN) to maximize culture diversity. Following morphological isolation of the fungal cultures, we extracted, amplified, and sequenced the full ITS region. We hypothesized that salamanders in the New York area would have a species-rich fungal microbiome that varies in composition by location.
Results/Conclusions
Our results suggest a diverse fungal community present on the skin microbiome of P. cinereus. From 27 individuals, we isolated over 100 morphologically-distinct strains. Forty-five of these distinct strains were selected for genomic identification and resulted in 37 OTUs, mainly in the divisions Ascomycota and Basidiomycota. The number of distinct OTUs we identified reveal a culturable species-rich fungal microbiome, the composition of which varied by location. The diversity revealed in our results also suggests the potential for certain strains of these skin-associated fungi present to be inhibitory or facilitatory to Bd growth. In the next stage of this project, we will perform challenge assays with these cultures and Bd in order to determine inhibitory potential and to assess if fungi play a critical and often overlooked role in the microbial defense of amphibians to Bd. Additionally, in the future, we hope to quantify the complex interspecific interactions between bacteria, fungi, and microbial pathogens.