Houwenhuyse Shira, Bulteel Lore, Vanoverberghe Isabel, Krzynowek Anna, Van de Maele Marlies, Coone Manon, Van den Wyngaert Silke, Sinnesael Arne, Stoks Robby, Decaestecker Ellen
Microbiome EcoEvo Group, Laboratory of Aquatic Biology, Department of Biology, Campus KULAK, Eteinne Sabbelaan 53, University of Leuven - KU Leuven, Kortrijk 8500, Belgium.
Laboratory of Microbiology, Department of Biochemistry and Microbiology, Faculty of Sciences, Karel Lodewijk Ledeganckstraat 35, Gent University, Gent 9000, Belgium.
ISME J. 2025 Jan 2;19(1). doi: 10.1093/ismejo/wrae249.
Organisms are facing multiple, potentially interacting stressors in natural populations. The ability of populations coping with combined stressors depends on their tolerance to individual stressors and how stressors interact, which may not be correctly captured in controlled laboratory settings. One reason for this is that the microbial communities in laboratory settings often differ from the natural environment, which could result in different stressor responses and interaction patterns. In this study, we investigated the impact of single and combined exposure to a toxic cyanobacterium and an oomycete parasite on the performance of three Daphnia magna genotypes. Daphnia individuals were sterilized and subsequently exposed to a natural or a laboratory-derived microbial inoculum. Survival, reproduction and body size were monitored, and gut microbiomes were characterized. Our study confirmed that natural and laboratory microbial inocula and gut microbiomes are differently structured. An antagonistic interaction between the two biotic stressors was revealed with respect to survival when Daphnia, across all three genotypes, were exposed to the laboratory microbial inoculum, with a higher survival in the multiple stressor treatment than in the single stressor treatments. In contrast, no antagonistic interaction was detected in Daphnia exposed to a natural microbial inoculum, where the interaction effects were mainly host genotype-dependent. Our results provide the first causal evidence that host-stressor interaction patterns may be shaped by the gut microbiome and the uptake from certain strains from the environment. This raises concern that the many multiple stressor studies on lab-cultured animals with a differently structured microbiome may provide misleading results.
在自然种群中，生物体面临着多种可能相互作用的应激源。种群应对复合应激源的能力取决于它们对单个应激源的耐受性以及应激源之间的相互作用方式，而在受控的实验室环境中可能无法正确捕捉到这些情况。原因之一是实验室环境中的微生物群落通常与自然环境不同，这可能导致不同的应激源反应和相互作用模式。在本研究中，我们调查了单独暴露和联合暴露于有毒蓝藻和卵菌寄生虫对三种大型溞基因型表现的影响。大型溞个体经过灭菌处理，随后暴露于天然或实验室来源的微生物接种物中。监测其生存、繁殖和体型，并对肠道微生物群进行表征。我们的研究证实，天然和实验室微生物接种物以及肠道微生物群的结构不同。当所有三种基因型的大型溞暴露于实验室微生物接种物时，在生存方面揭示了两种生物应激源之间的拮抗相互作用，复合应激源处理组的生存率高于单一应激源处理组。相比之下，在暴露于天然微生物接种物的大型溞中未检测到拮抗相互作用，其相互作用效应主要取决于宿主基因型。我们的结果提供了首个因果证据，表明宿主 - 应激源相互作用模式可能受到肠道微生物群以及从环境中摄取某些菌株的影响。这引发了人们的担忧，即许多针对具有不同结构微生物群的实验室养殖动物的复合应激源研究可能会提供误导性结果。
