Data from: Influence of immunogenetics, sex, and body condition on the cutaneous microbial communities of two giant salamanders

The complex association between hosts and microbial symbionts requires the implementation of multiple approaches to evaluate variation in host physiology. Within amphibians, heterogeneity in immunogenetic traits and cutaneous microbiota is associated with variation in disease resistance. Ozark (Cryptobranchus alleganiensis bishopi) and eastern hellbenders (C. a. alleganiensis) provide a model system to assess variation in host traits and microbial communities. Ozark hellbenders have experienced declines throughout their range, are federally endangered, and experience wound retardation that is absent in the eastern subspecies. Previous microbial investigations indicate differentiation in the composition of the skin microbiota of both hellbender subspecies, but it is not clear if these patterns are concurrent with diversity in the major histocompatibility complex (MHC) genes. We characterized the MHC IIB and the skin microbiota of hellbenders in Missouri, where both subspecies co-occur though not sympatric. We compared the microbiota composition and MHC diversity between both subspecies and investigated whether individual-level MHC diversity, sex, and body condition were associated with microbiota composition. Overall MHC IIB diversity was lower in Ozark hellbenders compared to the eastern subspecies. Multivariate statistical comparisons identified microbiota differentiation between Ozark and eastern hellbenders. MHC IIB allele presence/absence, allele divergence, body composition, and sex defined grouping of hellbender microbiotas within populations. Differentiation of the cutaneous microbiotas and MHC IIB genes between eastern and Ozark hellbenders suggest that differences exist in immunity between the two subspecies. This study demonstrates how simultaneous assessments of host genetic traits and microbiotas can inform patterns of microbial community structure in natural systems.

宿主与微生物共生体之间的复杂关联，需采用多种研究方法评估宿主生理状态的变异。在两栖动物中，免疫遗传特征与皮肤微生物群的异质性，均与疾病抗性差异显著相关。奥氏隐鳃鲵（Cryptobranchus alleganiensis bishopi）与东部隐鳃鲵（C. a. alleganiensis）是探究宿主特征与微生物群落变异的理想模型系统。奥氏隐鳃鲵在其整个分布区内种群数量持续衰退，被列为联邦濒危物种，且会出现伤口愈合迟缓的症状，而东部亚种并无此表现。既往微生物组研究表明，两种隐鳃鲵亚种的皮肤微生物群组成存在分化，但尚不明确这种分化是否与主要组织相容性复合体（major histocompatibility complex, MHC）基因的多样性相契合。本研究对密苏里州境内的隐鳃鲵（两种亚种同域分布但非同种群栖息）的MHC IIB基因与皮肤微生物群进行了表征，比较了两种亚种的微生物群组成与MHC多样性，并探究了个体水平的MHC多样性、性别与体况是否与微生物群组成存在关联。整体而言，奥氏隐鳃鲵的MHC IIB基因多样性低于东部亚种。多变量统计分析显示，奥氏隐鳃鲵与东部隐鳃鲵的皮肤微生物群存在显著分化。在种群内部，MHC IIB等位基因的有无、等位基因分化程度、体况与性别共同决定了隐鳃鲵微生物群的聚类模式。东部与奥氏隐鳃鲵的皮肤微生物群及MHC IIB基因的分化，提示两种亚种的免疫功能存在差异。本研究证实，同时评估宿主遗传特征与微生物群，能够揭示自然系统中微生物群落结构的构建规律。