Seasonal And Ontogenetic Variation Of Skin Microbial Communities And Relationships To Natural Disease Dynamics In Declining Amphibians

Keywords

16S amplicon sequencing; Community fingerprinting; Dysbiosis; Eleutherodactylus coqui; Host–pathogen dynamics; Lithobates yavapaiensis

Abstract

Recently, microbiologists have focused on characterizing the probiotic role of skin bacteria for amphibians threatened by the fungal disease chytridiomycosis. However, the specific characteristics of microbial diversity required to maintain health or trigger disease are still not well understood in natural populations. We hypothesized that seasonal and developmental transitions affecting susceptibility to chytridiomycosis could also alter the stability of microbial assemblages. To test our hypothesis, we examined patterns of skin bacterial diversity in two species of declining amphibians (Lithobates yavapaiensis and Eleutherodactylus coqui) affected by the pathogenic fungus Batrachochytrium dendrobatidis (Bd). We focused on two important transitions that affect Bd susceptibility: ontogenetic (from juvenile to adult) shifts in E. coqui and seasonal (from summer to winter) shifts in L. yavapaiensis. We used a combination of community-fingerprinting analyses and 16S rRNA amplicon sequencing to quantify changes in bacterial diversity and assemblage composition between seasons and developmental stages, and to investigate the relationship between bacterial diversity and pathogen load. We found that winter-sampled frogs and juveniles, two states associated with increased Bd susceptibility, exhibited higher diversity compared with summer-sampled frogs and adult individuals. Our findings also revealed that hosts harbouring higher bacterial diversity carried lower Bd infections, providing support for the protective role of bacterial communities. Ongoing work to understand skin microbiome resilience after pathogen disturbance has the potential to identify key taxa involved in disease resistance.

Publication Date

7-1-2015

Publication Title

Royal Society Open Science

Volume

2

Issue

7

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1098/rsos.140377

Socpus ID

84958213665 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/84958213665

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