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，需要采用多种研究方法来评估宿主生理的变异情况。在两栖动物中，免疫遗传性状与皮肤微生物群（cutaneous microbiota）的异质性，与疾病抗性的变异存在关联。奥索卡隐鳃鲵（*Cryptobranchus alleganiensis bishopi*）与东部隐鳃鲵（*C. a. alleganiensis*）为评估宿主性状与微生物群落变异提供了理想的模式系统。奥索卡隐鳃鲵在其分布范围内种群数量持续下降，被美国联邦政府列为濒危物种，且存在伤口愈合迟缓的现象，而东部隐鳃鲵亚种并无此问题。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，但尚不清楚这种分化是否与主要组织相容性复合体（major histocompatibility complex, MHC）基因的多样性存在同步性。本研究对密苏里州境内的隐鳃鲵的MHC IIB基因与皮肤微生物群进行了表征，该区域内两种亚种均有分布，但二者并未同域分布。我们比较了两种隐鳃鲵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、性别与身体状况是否与微生物群组成存在关联。总体而言，奥索卡隐鳃鲵的MHC IIB基因多样性低于东部隐鳃鲵亚种。多变量统计分析结果显示，奥索卡隐鳃鲵与东部隐鳃鲵的皮肤微生物群存在分化。MHC IIB等位基因的有无、等位基因分化程度、身体状况与性别，共同决定了种群内隐鳃鲵微生物群的聚类模式。东部与奥索卡隐鳃鲵之间的皮肤微生物群与MHC IIB基因分化，表明两个亚种的免疫功能存在差异。本研究阐明了同步评估宿主遗传性状与微生物群的研究思路，可为自然系统中的微生物群落结构模式提供科学阐释。