Toward building an open-access database of cultured amphibian skin bacteria to inform microbial function against chytridiomycosis

Background/Question/Methods

An increasing number of studies target amphibian skin for culture of symbiotic bacteria that function in antifungal defense.  Are antifungal bacteria closely related or clustered phylogenetically?  Are antifungal bacteria widespread geographically, and do they differ among host species and life-history stages? Here, we synthesize these studies and apply a bioinformatics approach to predict the extent of antifungal capacity across the bacterial phylogenetic tree.  We then use this information to filter publically available datasets from culture-independent studies.  By this method we compare species and treatments for bacterial antagonists of Batrachochytrium dendrobatidis.

Results/Conclusions

A preliminary analysis shows that antifungal bacterial isolates are clustered, but also widespread across a phylogenetic tree based on cultured bacteria.  These include bacteria from over 50 host species across North, Central, and South America, Europe, Australia, and Madagascar.  We can expand the list of known antifungal isolates to include closely related operational taxonomic units (OTUs).  The presence of these OTUs differs among species, changes through host development and differs by geography or environmental conditions of the host in a meta-analysis of amphibian skin-associated bacterial communities.  The predictive potential for this database motivates the goal to build upon this open-access database. This database and culture collection will be useful in future studies utilizing next-generation sequencing to identify potential antifungal function of bacterial communities, and for the identifying key symbionts for further genetic analyses.