While evidence for the role of the microbiome in shaping host stress tolerance is becoming well-established, to what extent this depends on the interaction between the host and its local microbiome is less clear. Therefore, we investigated whether locally adapted gut microbiomes affect host stress tolerance. In the water flea Daphnia magna, we studied if the host performs better when receiving a microbiome from their source region than from another region when facing a stressful condition, more in particular exposure to the toxic cyanobacteria Microcystis aeruginosa. Therefore, a reciprocal transplant experiment was performed in which recipient, germ-free D. magna, isolated from different ponds, received a donor microbiome from sympatric or allopatric D. magna that were pre-exposed to toxic cyanobacteria or not. We tested for effects on host life history traits and gut microbiome composition. Our data indicate that Daphnia interact with particular microbial strains mediating local adaptation in host stress tolerance. Most recipient D. magna individuals performed better when inoculated with sympatric than with allopatric microbiomes. This effect was most pronounced when the donors were pre-exposed to the toxic cyanobacteria, but this effect was also pond and genotype dependent. We discuss how this host fitness benefit is associated with microbiome diversity patterns.

虽然微生物组在塑造宿主胁迫耐受性方面的作用的证据越来越充分，但这在多大程度上取决于宿主与其局部微生物组之间的相互作用尚不清楚。因此，我们研究了局部适应的肠道微生物组是否会影响宿主的应激耐受性。在水蚤Daphnia magna中，我们研究了宿主在面临压力条件时，从其来源区域接收微生物组时是否比从另一个区域接收微生物组时表现更好，尤其是暴露于有毒蓝藻铜绿微囊藻。因此，进行了一项互惠移植实验，其中从不同池塘分离的无菌D. magna接受者接受来自同域或异域的供体微生物组D. magna是否预先暴露于有毒蓝藻。我们测试了对宿主生活史特征和肠道微生物组组成的影响。我们的数据表明，水蚤与特定微生物菌株相互作用，介导宿主应激耐受的局部适应。大多数接受者D. magna个体在接种同域微生物组时的表现优于异域微生物组。当供体预先暴露于有毒蓝藻时，这种效果最为明显，但这种效果也取决于池塘和基因型。我们讨论了这种宿主健康益处如何与微生物组多样性模式相关联。