title: First in Vivo Batrachochytrium dendrobatidis Transcriptomes Reveal Mechanisms of Host Exploitation, Host-Specific Gene Expression, and Expressed Genotype Shifts.
abstract: For generalist pathogens, host species represent distinct selective environments, providing unique challenges for resource acquisition and defense from host immunity, potentially resulting in host-dependent differences in pathogen fitness. Gene expression modulation should be advantageous, responding optimally to a given host and mitigating the costs of generalism. Batrachochytrium dendrobatidis (Bd), a fungal pathogen of amphibians, shows variability in pathogenicity among isolates, and within-strain virulence changes rapidly during serial passages through artificial culture. For the first time, we characterize the transcriptomic profile of Bd in vivo, using laser-capture microdissection. Comparison of Bd transcriptomes (strain JEL423) in culture and in two hosts (Atelopus zeteki and Hylomantis lemur), reveals >2000 differentially expressed genes that likely include key Bd defense and host exploitation mechanisms. Variation in Bd transcriptomes from different amphibian hosts demonstrates shifts in pathogen resource allocation. Furthermore, expressed genotype variant frequencies of Bd populations differ between culture and amphibian skin, and among host species, revealing potential mechanisms underlying rapid changes in virulence and the possibility that amphibian community composition shapes Bd evolutionary trajectories. Our results provide new insights into how changes in gene expression and infecting population genotypes can be key to the success of a generalist fungal pathogen.
authors.affiliation: Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York 14853 ellisona@cardiff.ac.uk.
authors.forename: Amy R
authors.identifier: 0000-0003-3885-6077
authors.initials: AR
authors.lastname: Ellison
authors.affiliation: Department of Biology, University of Maryland, College Park, Maryland 20742.
authors.forename: Graziella V
authors.identifier: 0000-0001-5264-4762
authors.initials: GV
authors.lastname: DiRenzo
authors.affiliation: Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York 14853.
authors.forename: Caitlin A
authors.initials: CA
authors.lastname: McDonald
authors.affiliation: Department of Biology, University of Maryland, College Park, Maryland 20742.
authors.forename: Karen R
authors.identifier: 0000-0002-2719-1551
authors.initials: KR
authors.lastname: Lips
authors.affiliation: Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York 14853.
authors.forename: Kelly R
authors.identifier: 0000-0001-5107-6206
authors.initials: KR
authors.lastname: Zamudio
mesh_terms: D000818:Animals; D002025:Bufonidae / Q000235:genetics / Q000382:microbiology; D008411:Chytridiomycota / Q000235:genetics* / Q000472:pathogenicity; D005786:Gene Expression Regulation; D005838:Genotype; D054884:Host-Pathogen Interactions / Q000235:genetics*; D006801:Humans; D059467:Transcriptome / Q000235:genetics*
keywords: Batrachochytrium dendrobatidis; gene expression; laser capture microdissection; pathogen; transcriptomics