TY - JOUR

T1 - Probiotic colonization of Xenopus laevis skin causes short-term changes in skin microbiomes and gene expression

AU - Madison, Joseph

AU - Osborne, Owen

AU - Ellison, Amy

AU - Griffith, Christina

AU - Gentry, Lindsey

AU - Gross, Harald

AU - Gratwicke, Brian

AU - Grayfer, Leon

AU - Muletz‐Wolz, Carly

PY - 2025/3/5

Y1 - 2025/3/5

N2 - Probiotic therapies have been suggested for amelioration efforts of wildlife disease such as chytridiomycosis caused by Batrachochytrium spp. in amphibians. However, there is a lack of information on how probiotic application affects resident microbial communities and immune responses. To better understand these interactions, we hypothesized that probiotic application would alter microbial community composition and host immune expression in Xenopus laevis. Accordingly, we applied three amphibian-derived and anti-Batrachochytrium bacteria strains (two Pseudomonas spp., and one Stenotrophomonas sp.) to X. laevis in monoculture and also as a cocktail. We quantified microbial community structure using 16S rRNA gene sequencing. We also quantified genes involved in X. laevis immune responses using RT-qPCR and skin transcriptomics over one and three-week periods. All probiotic treatments successfully colonized X. laevis skin for three weeks, but with differential ASV sequence counts over time. Bacterial community and immune gene effects were most pronounced at week 1 post-probiotic exposure and decreased thereafter. All probiotic treatments caused initial changes to bacterial community alpha and beta diversity, including reduction in diversity from pre-exposure anti-Batrachochytrium bacterial ASV relative abundance. Probiotic colonization by Pseudomonas probiotic strain RSB5.4 reduced expression of regulatory T cell marker (FOXP3, measured with RT-qPCR) and caused the greatest gene expression changes detected by transcriptomics. Single bacterial strains and mixed cultures therefore altered amphibian microbiome-immune interactions. This work will help to improve our understanding of the role of the microbiome-immune interface underlying both disease dynamics and emergent eco-evolutionary processes.

AB - Probiotic therapies have been suggested for amelioration efforts of wildlife disease such as chytridiomycosis caused by Batrachochytrium spp. in amphibians. However, there is a lack of information on how probiotic application affects resident microbial communities and immune responses. To better understand these interactions, we hypothesized that probiotic application would alter microbial community composition and host immune expression in Xenopus laevis. Accordingly, we applied three amphibian-derived and anti-Batrachochytrium bacteria strains (two Pseudomonas spp., and one Stenotrophomonas sp.) to X. laevis in monoculture and also as a cocktail. We quantified microbial community structure using 16S rRNA gene sequencing. We also quantified genes involved in X. laevis immune responses using RT-qPCR and skin transcriptomics over one and three-week periods. All probiotic treatments successfully colonized X. laevis skin for three weeks, but with differential ASV sequence counts over time. Bacterial community and immune gene effects were most pronounced at week 1 post-probiotic exposure and decreased thereafter. All probiotic treatments caused initial changes to bacterial community alpha and beta diversity, including reduction in diversity from pre-exposure anti-Batrachochytrium bacterial ASV relative abundance. Probiotic colonization by Pseudomonas probiotic strain RSB5.4 reduced expression of regulatory T cell marker (FOXP3, measured with RT-qPCR) and caused the greatest gene expression changes detected by transcriptomics. Single bacterial strains and mixed cultures therefore altered amphibian microbiome-immune interactions. This work will help to improve our understanding of the role of the microbiome-immune interface underlying both disease dynamics and emergent eco-evolutionary processes.

M3 - Article

JO - Infection and Immunity

JF - Infection and Immunity

SN - 0019-9567

ER -