Longo Ana V, Zamudio Kelly R
Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA.
ISME J. 2017 Feb;11(2):349-361. doi: 10.1038/ismej.2016.138. Epub 2016 Dec 9.
Fluctuating environments can modulate host-pathogen interactions by providing a temporary advantage to one of the interacting organisms. However, we know very little about how environmental conditions facilitate beneficial interactions between hosts and their microbial communities, resulting in individual persistence with a particular pathogen. Here, we experimentally infected Eleutherodactylus coqui frogs with the fungal pathogen Batrachochytrium dendrobatidis (Bd) under environmental conditions known to confer the survival advantage to the host during the warm-wet season, or alternatively to the pathogen during the cool-dry season. We used 16S rRNA amplicon sequencing to quantify changes in bacterial richness and phylogenetic diversity, and identified operational taxonomic units (OTUs) that became overrepresented or suppressed as a consequence of Bd infection. During the warm-wet season, frogs limited Bd infections, recruited putatively beneficial bacteria and returned to pre-infection levels of richness and phylogenetic diversity. In contrast, during the cool-dry season, Bd infections kept increasing through time, and bacterial diversity remained constant. Our findings confirm that infection outcome not only depends on abiotic factors, but also on biotic interactions between hosts and their associated bacterial communities.
波动的环境可以通过为相互作用的生物体之一提供暂时优势来调节宿主与病原体之间的相互作用。然而，我们对环境条件如何促进宿主与其微生物群落之间的有益相互作用了解甚少，而这种相互作用会导致个体在感染特定病原体的情况下仍能存活。在这里，我们在已知温暖湿润季节有利于宿主存活、凉爽干燥季节有利于病原体存活的环境条件下，用真菌病原体蛙壶菌（Batrachochytrium dendrobatidis，Bd）对寇氏雨蛙（Eleutherodactylus coqui）进行了实验性感染。我们使用16S rRNA扩增子测序来量化细菌丰富度和系统发育多样性的变化，并确定了因感染Bd而数量增加或减少的可操作分类单元（OTU）。在温暖湿润季节，青蛙限制了Bd感染，招募了可能有益的细菌，并恢复到感染前的丰富度和系统发育多样性水平。相比之下，在凉爽干燥季节，Bd感染随时间不断增加，细菌多样性保持不变。我们的研究结果证实，感染结果不仅取决于非生物因素，还取决于宿主与其相关细菌群落之间的生物相互作用。
