ABSTRACT

The world is undergoing a sixth mass extinction, and the drastic decline of amphibians in the last several decades is a major contributing factor. The spread of the deadly Batrachochytrium dendrobatidis (Bd) fungus is a major causative agent, and captive breeding programs are under way to try and save endangered populations. However, how captivity affects Bd infection and the skin microbiota is not clear. We identified the skin bacteria of the South Australian frog Crinia signifera and showed that their culture-dependent skin microbiota is moderately stable in cohorts sampled from the same location in subsequent years. Their microbiota was also structurally different to that of a sympatric frog species, Limnodynastes tasmaniensis, indicating a specific microbial signature. Twenty-four C. signifera were placed into captivity for four weeks, exposed to a range of water salinity levels, during which time there was a significant reduction in identifiable skin bacterial species diversity, richness, and a change in microbial structure. The infection intensity of Bd was also significantly reduced in captivity, with some frogs becoming completely clear of infection, whilst water salinity level was not a significant determinant of Bd infection or skin microbiota.

摘要

世界正在经历第六次大规模灭绝，过去几十年两栖动物的急剧减少是一个主要因素。致命的Batrachochytrium dendrobatidis ( Bd ) 真菌的传播是主要病原体，目前正在进行圈养繁殖计划以试图拯救濒临灭绝的种群。然而，圈养如何影响Bd感染和皮肤微生物群尚不清楚。我们鉴定了南澳大利亚青蛙Crinia signifera的皮肤细菌，并表明它们的培养依赖性皮肤微生物群在随后几年从同一地点取样的队列中是适度稳定的。它们的微生物群在结构上也与同域青蛙物种不同，Limnodynastes tasmaniensis，表明特定的微生物特征。将 24只C. signifera圈养 4 周，暴露在一定范围的水盐度水平下，在此期间，可识别的皮肤细菌物种多样性、丰富度和微生物结构的变化显着降低。Bd的感染强度在圈养中也显着降低，一些青蛙完全没有感染，而水盐度水平不是Bd感染或皮肤微生物群的重要决定因素。