Polymorphic repetitive loci of the amphibian pathogen Batrachochytrium dendrobatidis

Abstract

Batrachochytrium dendrobatidis (Bd), the cause of a fatal fungal skin disease of amphibians that has led to massive die-offs, global declines and extinctions, has spread internationally as a pandemic clone with low genetic diversity. A need exists to develop highly polymorphic markers to determine centers of origin and patterns of spread to assist in the development of management strategies. Comparison of paralogous sequences, obtained from the 2 sequenced Bd genomes, indicates useful levels of inter-strain polymorphism in repetitive fragments. We assessed 6 repetitive loci for variation within and among Australian isolates using standard fragment analysis and capillary electrophoresis-single strand conformation polymorphism (CE-SSCP) analysis. Confirmation of inter-isolate polymorphism was achieved for 2 marker systems, highlighting the potential of repetitive loci for the development of polymorphic markers in Bd. In addition, we found that repetitive loci in Bd include possible orthologs of virulence-related genes from pathogenic fungi.