Belden Lisa K, Hughey Myra C, Rebollar Eria A, Umile Thomas P, Loftus Stephen C, Burzynski Elizabeth A, Minbiole Kevin P C, House Leanna L, Jensen Roderick V, Becker Matthew H, Walke Jenifer B, Medina Daniel, Ibáñez Roberto, Harris Reid N
Department of Biological Sciences, Virginia Tech Blacksburg, VA, USA ; Smithsonian Tropical Research Institute Balboa, Ancón, Republic of Panamá
Department of Biological Sciences, Virginia Tech Blacksburg, VA, USA.
Front Microbiol. 2015 Oct 27;6:1171. doi: 10.3389/fmicb.2015.01171. eCollection 2015.
Vertebrates, including amphibians, host diverse symbiotic microbes that contribute to host disease resistance. Globally, and especially in montane tropical systems, many amphibian species are threatened by a chytrid fungus, Batrachochytrium dendrobatidis (Bd), that causes a lethal skin disease. Bd therefore may be a strong selective agent on the diversity and function of the microbial communities inhabiting amphibian skin. In Panamá, amphibian population declines and the spread of Bd have been tracked. In 2012, we completed a field survey in Panamá to examine frog skin microbiota in the context of Bd infection. We focused on three frog species and collected two skin swabs per frog from a total of 136 frogs across four sites that varied from west to east in the time since Bd arrival. One swab was used to assess bacterial community structure using 16S rRNA amplicon sequencing and to determine Bd infection status, and one was used to assess metabolite diversity, as the bacterial production of anti-fungal metabolites is an important disease resistance function. The skin microbiota of the three Panamanian frog species differed in OTU (operational taxonomic unit, bacterial species) community composition and metabolite profiles, although the pattern was less strong for the metabolites. Comparisons between frog skin bacterial communities from Panamá and the US suggest broad similarities at the phylum level, but key differences at lower taxonomic levels. In our field survey in Panamá, across all four sites, only 35 individuals (26%) were Bd infected. There was no clustering of OTUs or metabolite profiles based on Bd infection status and no clear pattern of west-east changes in OTUs or metabolite profiles across the four sites. Overall, our field survey data suggest that different bacterial communities might be producing broadly similar sets of metabolites across frog hosts and sites. Community structure and function may not be as tightly coupled in these skin symbiont microbial systems as it is in many macro-systems.
包括两栖动物在内的脊椎动物体内寄生着各种各样的共生微生物,这些微生物有助于宿主抵抗疾病。在全球范围内,尤其是在山地热带系统中,许多两栖动物物种受到一种壶菌——蛙壶菌(Batrachochytrium dendrobatidis,简称Bd)的威胁,这种壶菌会引发一种致命的皮肤病。因此,Bd可能是栖息在两栖动物皮肤上的微生物群落多样性和功能的强大选择因子。在巴拿马,两栖动物数量的减少以及Bd的传播情况都得到了追踪。2012年,我们在巴拿马完成了一项实地调查,以研究在Bd感染背景下的蛙类皮肤微生物群。我们聚焦于三种蛙类物种,从四个地点的总共136只青蛙中,每只青蛙采集两份皮肤拭子样本。这些地点自Bd出现后,从西到东在时间上存在差异。一份拭子用于通过16S rRNA扩增子测序评估细菌群落结构并确定Bd感染状况,另一份用于评估代谢物多样性,因为细菌产生抗真菌代谢物是一项重要的抗病功能。巴拿马这三种蛙类物种的皮肤微生物群在OTU(操作分类单元,约等同于细菌物种)群落组成和代谢物谱方面存在差异,不过代谢物方面的差异模式不太明显。巴拿马和美国的蛙类皮肤细菌群落之间的比较表明,在门水平上有广泛的相似性,但在较低分类水平上存在关键差异。在我们于巴拿马进行的实地调查中,在所有四个地点,只有35只个体(约26%)被Bd感染。基于Bd感染状况,OTU或代谢物谱没有聚类现象,并且在四个地点之间,OTU或代谢物谱也没有明显的东西向变化模式。总体而言,我们的实地调查数据表明,不同的细菌群落可能在不同的蛙类宿主和地点产生大致相似的代谢物集合。在这些皮肤共生微生物系统中,群落结构和功能的耦合程度可能不像在许多宏观系统中那样紧密。