Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Instituto de Biologia, Universidade Estadual de Campinas, R. Monteiro Lobato, 255 - CEP 13083-862, Campinas, São Paulo, Brazil.
Sistema Nacional de Investigación, SENACYT, Building 205, City of Knowledge, Clayton, Panama, Republic of Panama.
FEMS Microbiol Ecol. 2021 Apr 6;97(4). doi: 10.1093/femsec/fiab030.
Amphibian skin bacteria may confer protection against the fungus Batrachochytrium dendrobatidis (Bd), but responses of skin bacteria to different Bd lineages are poorly understood. The global panzootic lineage (Bd-GPL) has caused amphibian declines and extinctions globally. However, other lineages are enzootic (Bd-Asia-2/Brazil). Increased contact rates between Bd-GPL and enzootic lineages via globalization pose unknown consequences for host-microbiome-pathogen dynamics. We conducted a laboratory experiment and used 16S rRNA amplicon-sequencing to assess: (i) whether two lineages (Bd-Asia-2/Brazil and Bd-GPL) and their recombinant, in single and mixed infections, differentially affect amphibian skin bacteria; (ii) and the changes associated with the transition to laboratory conditions. We determined no clear differences in bacterial diversity among Bd treatments, despite differences in infection intensity. However, we observed an additive effect of mixed infections on bacterial alpha diversity and a potentially antagonistic interaction between Bd genotypes. Additionally, observed changes in community composition suggest a higher ability of Bd-GPL to alter skin bacteria. Lastly, we observed a drastic reduction in bacterial diversity and a change in community structure in laboratory conditions. We provide evidence for complex interactions between Bd genotypes and amphibian skin bacteria during coinfections, and expand on the implications of experimental conditions in ecological studies.
两栖动物皮肤细菌可能对真菌蛙壶菌（Batrachochytrium dendrobatidis，Bd）提供保护，但皮肤细菌对不同 Bd 谱系的反应仍知之甚少。全球泛生谱系（Bd-GPL）已在全球范围内导致两栖动物减少和灭绝。然而，其他谱系是地方流行的（Bd-Asia-2/Brazil）。全球化导致 Bd-GPL 与地方流行谱系之间接触率的增加，对宿主微生物群-病原体动态可能带来未知的后果。我们进行了一项实验室实验，并使用 16S rRNA 扩增子测序来评估：（i）两个谱系（Bd-Asia-2/Brazil 和 Bd-GPL）及其重组体，在单一和混合感染中，是否会对两栖动物皮肤细菌产生不同的影响；（ii）以及与过渡到实验室条件相关的变化。尽管感染强度存在差异，但我们在 Bd 处理组之间没有观察到细菌多样性的明显差异。然而，我们观察到混合感染对细菌 α 多样性有累加效应，Bd 基因型之间存在潜在的拮抗相互作用。此外，观察到的群落组成变化表明，Bd-GPL 有更高的能力改变皮肤细菌。最后，我们观察到实验室条件下细菌多样性的急剧减少和群落结构的变化。我们为 Bd 基因型和两栖动物皮肤细菌在混合感染期间的复杂相互作用提供了证据，并扩展了实验条件对生态研究的影响。
