Project description:Global amphibian declines and extinction events are currently occurring at an unprecedented rate. While various factors are influencing these declines, one factor that is readily identifiable is disease. Specifically, the fungal pathogen Batrachochytrium dendrobatidis is thought to play a major role in amphibian declines in tropical and neotropical regions of the globe. While the effects of this chytrid fungus have been shown to be devastating, certain individuals and relict populations have shown resistance. This resistance has been attributed in part to the cutaneous microbiome. Many identified bacterial species that make up the microbiome have shown anti-B. dendrobatidis activity in vitro. One bacteria that is commonly associated as being a member of the amphibian microbiome across amphibian species and shows such anti-B. dendrobatidis activity is Serratia marcescens. Here, we look at transcriptomic shifts in gene expression of S. marcescens (high homology to strain WW4) in response to both live and heat-killed B. dendrobatidis.
Project description:This experiment examined the transcriptional response of juvenile amphibian hosts (common frog, Rana temporaria) to two important amphibian pathogens: Batrachochytrium dendrobatidis (Bd) and Ranavirus. Common frogs are non-model organisms which do not have a reference genome.
Project description:Chytridiomycosis is an emerging infectious disease of amphibians caused by the chytrid Batrachochytrium dendrobatidis (Bd). The disease has been associated with global amphibian declines and is driving the species in the wild to extinction. Using DNA microarray technology we have analysed transcriptional changes in Xenopus tropicalis during the course (7 and 42 days) of infection by Bd under warm (26oC) and cold (18oC) temperatures.
Project description:The Global Pandemic Lineage (GPL) of the amphibian pathogen Batrachochytrium dendrobatidis (Bd) has been described as a main driver of amphibian extinctions on nearly every continent. Near complete genome of three Bd-GPL strains have enabled studies of the pathogen but the genomic features that set Bd-GPL apart from other Bd lineages is not well understood due to a lack of high-quality genome assemblies and annotations from other lineages. We used long-read DNA sequencing to assemble high-quality genomes of three Bd-BRAZIL isolates and one non-pathogen outgroup species Polyrhizophydium stewartii (Ps) strain JEL0888, and compared these to genomes of previously sequenced Bd-GPL strains. The Bd-BRAZIL assemblies range in size between 22.0 and 26.1 Mb and encode 8495-8620 protein-coding genes for each strain. Our pan-genome analysis provided insight into shared and lineage-specific gene content. The core genome of Bd consists of 6278 conserved gene families, with 202 Bd-BRAZIL and 172 Bd-GPL specific gene families. We discovered gene copy number variation in pathogenicity gene families between Bd-BRAZIL and Bd-GPL strains though none were consistently expanded in Bd-GPL or Bd-BRAZIL strains. Comparison within the Batrachochytrium genus and two closely related non-pathogenic saprophytic chytrids identified variation in sequence and protein domain counts. We further test these new Bd-BRAZIL genomes to assess their utility as reference genomes for transcriptome alignment and analysis. Our analysis examines the genomic variation between strains in Bd-BRAZIL and Bd-GPL and offers insights into the application of these genomes as reference genomes for future studies.