Variation in phenotype and virulence among enzootic and panzootic amphibian chytrid lineages
Variation in phenotype and virulence among enzootic and panzootic amphibian chytrid lineages
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DOI：
10.1016/j.funeco.2016.11.007
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发表时间：
2017-04-01
期刊：
影响因子：
2.9
通讯作者：
Zamudio, K. R.
中科院分区：
文献类型：
--
作者：
Becker, C. G.;Greenspan, S. E.;Zamudio, K. R.
真菌Batrachochytrium dendrobatim（Bd-GPL）的全球泛动物谱系正在威胁全世界的两栖动物。与此相反，在Bd历史早期分化的四个谱系（Bd-Brazil，Bd-CH，Bd-Cape和Bd-Korea）尚未与两栖动物的衰落直接相关。Bd的进化可能是对宿主和环境施加的强大选择压力的反应，导致病原体表型和基因型之间的差异，这些差异可能直接影响毒力。在这里，我们报告了Bd-Brazil和Bd-GPL的表型、基因型和毒力的变异。具体而言，我们（i）使用了一个控制感染实验，以比较一个Bd-Brazil和三个Bd-GPL分离株对北美两栖类宿主（Lithobates sylvaticus）的毒力，（ii）测试了巴西Bd分离株之间的相对表型和基因型分化，（iii）测试了环境变量和Bd表型之间可能的相关性。我们发现Bd-GPL分离株之间的毒力存在很大差异，并发现我们的Bd-Brazil分离株的毒力与北美Bd-GPL的平均毒力相当。感染来自巴拿马的Bd-GPL分离株的北美宿主没有显示出显著的死亡率。Bd表型在采样地点之间差异显着，这些表型既不是空间聚类，也不与任何环境变量相关。此外，我们发现一个令人惊讶的缺乏相关性基因型分歧和游动孢子和游动孢子囊的大小在我们的样品。虽然Bd-Brazil对L.与一个Bd-GPL分离物相比，这个地方性谱系在我们的实验性第N个美洲宿主中仍然引起约50%的死亡率，这表明如果引入到幼稚的野生种群中，Bd-Brazil具有杀死两栖动物的潜力。我们的研究结果强调，表征多个Bd分离株和谱系的毒力对于理解Bd的进化历史和多样性是重要的。(C)2016 Elsevier Ltd和英国真菌学会。All rights reserved.
The Global Panzootic Lineage of the fungus Batrachochytrium dendrobatidis (Bd-GPL) is threatening amphibians worldwide. In contrast, four lineages (Bd-Brazil, Bd-CH, Bd-Cape, and Bd-Korea) that diverged early in the history of Bd have not yet been directly linked to amphibian declines. Bd likely evolves in response to strong selective pressure imposed by hosts and the environment, leading to differences among pathogen phenotypes and genotypes that may directly affect virulence. Here, We report on variation in phenotype, genotype, and virulence of Bd-Brazil and Bd-GPL. Specifically, we (i) used a controlled infection experiment to compare virulence between one Bd-Brazil and three Bd-GPL isolates on a North American amphibian host (Lithobates sylvaticus), (ii) tested for relative phenotypic and genotypic differentiation among Bd isolates from Brazil, and (iii) tested for possible correlations between environmental variables and Bd phenotypes. We found substantial variation in virulence among Bd-GPL isolates and found that our Bd-Brazil isolate showed virulence comparable to an average North American Bd-GPL. North American hosts infected with a Bd-GPL isolate from Panama did not show significant mortality. Bd phenotypes varied significantly across sampling locations; these phenotypes were neither spatially clustered nor correlated with any environmental variables. Additionally, we found a surprising lack of correlation between genotypic divergence and zoospore and zoosporangium sizes in our sample. Although Bd-Brazil was less virulent infecting L. sylvaticus than one Bd-GPL isolate, this endemic lineage still caused-50% mortality in our experimental Ndrth American hosts, This indicates that Bd-Brazil has the potential to kill amphibians if introduced to na ve wild populations. Our findings underscore that characterizing virulence of multiple Bd isolates and lineages is important for understanding the evolutionary history and diversity of Bd. (C) 2016 Elsevier Ltd and British Mycological Society. All rights reserved.