EAPSI:Using Molecular Techniques to Understand Virulence of the Amphibian-Killing Fungus, Batrachochytrium Dendrobatidis

Mcdonald Caitlin A, Ithaca NY

Investigators

Abstract

The pathogenic fungus, Batrachochytrium dendrobatidis (Bd), is responsible for ongoing global amphibian population declines. It is capable of infecting over 500 amphibian species, however its ability to cause disease in such a diverse range of hosts is still not fully understood. This is in part because there is extensive variability within the fungal lineage. While some fungal isolates cause severe disease and death, others appear to have little effect on the host. In order to better understand this variation, this project will identify fungal gene and protein expression corresponding to virulence in a range of Bd strains from eastern Australia, a region of both high Bd prevalence and impact. This research will be conducted at James Cook University in association with Dr. Lee Berger, who has remained a leading expert on Bd since publishing the first report of the pathogen in 1998. As next-generation sequencing technologies have become more accessible to studies involving non-model systems, our understanding of Bd pathogenicity has improved. There is growing evidence that secreted proteases and peptidases are involved in Bd?s ability to invade and persist within the amphibian host. Moreover this reliance on secreted virulence factors has been demonstrated in a range of other dermatophytic fungal species. Because such mechanisms may play a key role in Bd virulence, this study will quantify the Bd secretome, or the complete profile of all proteins secreted by a cell or organism. Pathogenically and evolutionarily distinct Australian Bd isolates will be grown under a variety of substrate conditions. Using RNA sequencing-directed shotgun proteomics, the secretome of each isolate will be characterized. Differential protein secretion will then be quantified, and changes in the secretome will be correlated to known strain virulence. This study will identify targets for future proteogenomic and functional protein studies, in turn informing host-pathogen-environment dynamics and related amphibian conservation efforts. This NSF EAPSI award is funded in collaboration with the Australian Academy of Science.