Journal of Chemical Ecology

, Volume 38, Issue 8, pp 958–965

Synergistic Inhibition of the Lethal Fungal Pathogen Batrachochytrium dendrobatidis: The Combined Effect of Symbiotic Bacterial Metabolites and Antimicrobial Peptides of the Frog Rana muscosa

  • Jillian M. Myers
  • Jeremy P. Ramsey
  • Alison L. Blackman
  • A. Elizabeth Nichols
  • Kevin P. C. Minbiole
  • Reid N. Harris
Article

Abstract

A powerful mechanism for protection against disease in animals is synergy between metabolites present in the natural microbiota of the host and antimicrobial peptides (AMPs) produced by the host. We studied this method of protection in amphibians in regard to the lethal disease chytridiomycosis, which is caused by Batrachochytrium dendrobatidis (Bd). In this study, we show that the AMPs of Rana muscosa, as well as the metabolite 2,4-diacetylphloroglucinol (2,4-DAPG) from Pseudomonas fluorescens, a bacterial species normally found on the skin of R. muscosa, were inhibitory to the growth of Bd in vitro. When both AMPs and 2,4-DAPG were used in growth inhibition assays, they worked synergistically to inhibit the growth of Bd. This synergy resulted in reduced minimum concentrations necessary for inhibition by either 2,4-DAPG or AMPs. This inhibitory concentration of AMPs did not inhibit the growth of a P. fluorescens strain that produced 2,4-DAPG in vitro, although its growth was inhibited at higher peptide concentrations. These data suggest that the AMPs secreted onto frog skin and the metabolites secreted by the resident beneficial bacteria may work synergistically to enhance protection against Bd infection on amphibian skin. These results may aid conservation efforts to augment amphibian skins’ resistance to chytridiomycosis by introducing anti-Bd bacterial species that work synergistically with amphibian AMPs.

Keywords

Batrachochytrium dendrobatidis Antimicrobial peptides Metabolites Pseudomonas fluorescens Synergy 2,4-diacetylphloroglucinol Chytridiomycosis Amphibian conservation Probiotic 

Supplementary material

10886_2012_170_MOESM1_ESM.docx (14 kb)
Supplemental Fig. 1Inhibition of Batrachochytrium dendrobatidis growth in vitro by mixtures of AMPs and 2,4-DAPG. A statistically significant interaction between Rana muscosa AMPs and 2,4-DAPG exists as determined by ANOVA (F = 6.13; df = 8,63; P < 0.001). This assay was conducted twice, with ten total replicates per sample. All points denote means, and standard error bars have been omitted for clarity (DOCX 13 kb)

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Copyright information

© Springer Science+Business Media, LLC 2012

Authors and Affiliations

  • Jillian M. Myers
    • 1
  • Jeremy P. Ramsey
    • 1
  • Alison L. Blackman
    • 1
  • A. Elizabeth Nichols
    • 1
  • Kevin P. C. Minbiole
    • 1
    • 2
  • Reid N. Harris
    • 1
  1. 1.Department of BiologyJames Madison UniversityHarrisonburgUSA
  2. 2.Department of ChemistryVillanova UniversityVillanovaUSA

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