Risely A, Byrne Phillip G, Hoye Bethany J, Silla Aimee J
School of Science, Engineering and Environment, Salford University, Manchester, UK.
School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, New South Wales, Australia.
Mol Ecol. 2024 Jan;33(2):e17203. doi: 10.1111/mec.17203. Epub 2023 Nov 14.
The amphibian skin microbiome plays a crucial role in host immunity and pathogen defence, yet we know little about the environmental drivers of skin microbial variation across host individuals. Inter-individual variation in the availability of micro-nutrients such as dietary carotenoids, which are involved in amphibian immunity, may be one factor that influences skin microbial assembly across different life history stages. We compared the effect of four carotenoid supplementation regimes during different life stages on the adult skin microbiome using a captive population of the critically endangered southern corroboree frog, Pseudophryne corroboree. We applied 16S rRNA sequencing paired with joint-species distribution models to examine the effect of supplementation on taxon abundances. We found that carotenoid supplementation had subtle yet taxonomically widespread effects on the skin microbiome, even 4.5 years post supplementation. Supplementation during any life-history stage tended to have a positive effect on the number of bacterial taxa detected, although explanatory power was low. Some genera were sensitive to supplementation pre-metamorphosis, but most demonstrated either additive or dominant effects, whereby supplementation during one life history stage had intermediate or similar effects, respectively, to supplementation across life. Carotenoid supplementation increased abundances of taxa belonging to lactic acid bacteria, including Lactococcus and Enterococcus, a group of bacteria that have previously been linked to protection against the amphibian fungal pathogen Batrachochytrium dendrobatidis (Bd). While the fitness benefits of these microbial shifts require further study, these results suggest a fundamental relationship between nutrition and the amphibian skin microbiome which may be critical to amphibian health and the development of novel conservation strategies.
两栖动物的皮肤微生物群落在宿主免疫和病原体防御中起着至关重要的作用，但我们对宿主个体间皮肤微生物变异的环境驱动因素知之甚少。参与两栖动物免疫的微量营养素（如膳食类胡萝卜素）可利用性的个体间差异，可能是影响不同生命史阶段皮肤微生物群落组装的一个因素。我们使用极度濒危的南部灌丛蛙（Pseudophryne corroboree）的圈养种群，比较了不同生命阶段四种类胡萝卜素补充方案对成年蛙皮肤微生物群的影响。我们应用16S rRNA测序并结合联合物种分布模型，来检验补充类胡萝卜素对分类单元丰度的影响。我们发现，即使在补充类胡萝卜素4.5年后，其对皮肤微生物群仍有微妙但在分类学上广泛的影响。在任何生命史阶段进行补充往往对检测到的细菌分类单元数量有积极影响，尽管解释力较低。一些属在变态前对补充类胡萝卜素敏感，但大多数表现出累加或主导效应，即在一个生命史阶段进行补充分别对整个生命阶段补充有中等或相似的影响。补充类胡萝卜素增加了属于乳酸菌的分类单元的丰度，包括乳球菌属和肠球菌属，这是一组先前与抵御两栖动物真菌病原体蛙壶菌（Bd）相关的细菌。虽然这些微生物变化对健康的益处需要进一步研究，但这些结果表明营养与两栖动物皮肤微生物群之间存在着基本关系，这可能对两栖动物健康和新型保护策略的制定至关重要。
