Two new publications!
I've just published two related papers on amphibian chytridiomycosis:
Grogan, L. F., Cashins, S. D., Skerratt, L. F., Berger, L., McFadden, M. S., Harlow, P., Hunter, D. A., Scheele, B. C., Mulvenna, J. (2018) Evolution of resistance to chytridiomycosis is associated with a robust early immune response. Molecular Ecology, doi:10.1111/MEC.14493.
Grogan, L. F., Mulvenna, J., Gummer, J. P. A., Scheele, B. C., Berger, L., Cashins, S. D., McFadden, M. S., Harlow, P., Hunter, D. A., Trengove, R. D., Skerratt, L. F. (2018) Survival, gene and metabolite responses of Litoria verreauxii alpinafrogs to fungal disease chytridiomycosis. Scientific Data, doi:10.1038/sdata.2018.33.
Potentiating the evolution of immunity is a promising strategy for addressing biodiversity diseases. Assisted selection for infection resistance may enable the recovery and persistence of amphibians threatened by chytridiomycosis, a devastating fungal skin disease threatening hundreds of species globally. However, knowledge of the mechanisms involved in the natural evolution of immunity to chytridiomycosis is limited. Understanding the mechanisms of such resistance may help speed‐assisted selection. Using a transcriptomics approach, we examined gene expression responses of endangered alpine tree frogs (Litoria verreauxii alpina) to subclinical infection, comparing two long‐exposed populations with a naïve population. We performed a blinded, randomized and controlled exposure experiment, collecting skin, liver and spleen tissues at 4, 8 and 14 days postexposure from 51 wild‐caught captively reared infection‐naïve adult frogs for transcriptome assembly and differential gene expression analyses. We analysed our results in conjunction with infection intensity data, and the results of a large clinical survival experiment run concurrently with individuals from the same clutches. Here, we show that frogs from an evolutionarily long‐exposed and phenotypically more resistant population of the highly susceptible alpine tree frog demonstrate a more robust innate and adaptive immune response at the critical early subclinical stage of infection when compared with two more susceptible populations. These results are consistent with the occurrence of evolution of resistance against chytridiomycosis, help to explain underlying resistance mechanisms, and provide genes of potential interest and sequence data for future research. We recommend further investigation of cell‐mediated immunity pathways, the role of interferons and mechanisms of lymphocyte suppression.
The fungal skin disease chytridiomycosis has caused the devastating decline and extinction of hundreds of amphibian species globally, yet the potential for evolving resistance, and the underlying pathophysiological mechanisms remain poorly understood. We exposed 406 naïve, captive-raised alpine tree frogs (Litoria verreauxii alpina) from multiple populations (one evolutionarily naïve to chytridiomycosis) to the aetiological agent Batrachochytrium dendrobatidis in two concurrent and controlled infection experiments. We investigated (A) survival outcomes and clinical pathogen burdens between populations and clutches, and (B) individual host tissue responses to chytridiomycosis. Here we present multiple interrelated datasets associated with these exposure experiments, including animal signalment, survival and pathogen burden of 355 animals from Experiment A, and the following datasets related to 61 animals from Experiment B: animal signalment and pathogen burden; raw RNA-Seq reads from skin, liver and spleen tissues; de novo assembled transcriptomes for each tissue type; raw gene expression data; annotation data for each gene; and raw metabolite expression data from skin and liver tissues. These data provide an extensive baseline for future analyses.