分子工具的快速技术进步使我们能够发现隐藏在寄生虫及其宿主中的新维度:它们的微生物组。越来越多,寄生虫学家描述了面对寄生虫感染的宿主微生物组变化,揭示了这些微观快速进化实体影响宿主-寄生虫相互作用的潜力。然而,宿主微生物群的大多数变化似乎取决于所讨论的宿主和寄生虫物种。此外,与其他微生物组影响因素相比,我们应该了解寄生虫感染作为微生物组调节剂的相对作用(例如,主机大小,年龄,性)。这里,我们对单个中间宿主物种的微生物组进行了表征,该物种被两种属于不同门的寄生虫感染:棘头虫plagiorhynchusallisonae和dilepidida,同时从同一地区收集的感染Serrulata两栖动物。我们使用16SrRNA原核基因的v4高变区来鉴定未感染的血淋巴细菌群落,棘头法仑感染,和受食虫感染的两栖动物,以及两栖动物直接环境中的细菌和感染它们的寄生虫中的细菌。我们的结果表明,寄生虫感染与宿主细菌群落丰富度的差异比两栖动物的大小更密切相关,雌性两栖动物中存在两栖动物卵,甚至是寄生虫。被棘头鱼感染的两栖动物的细菌群落差异最大,与感染和未感染的宿主相比,α多样性显着下降。根据寄生虫感染中微生物组变化的物种特异性性质,我们发现了独特的微生物类群与被每种寄生虫感染的宿主相关联,以及仅在寄生虫物种及其感染宿主之间共享的类群。然而,在所有被寄生的两栖类动物中都检测到一些细菌类群(无论寄生虫种类如何),但不是在未感染的两栖动物或环境中。我们认为,与远缘蠕虫寄生的所有宿主相关的共享细菌可能在帮助宿主防御或寄生虫成功方面很重要,因此可以与宿主-寄生虫的进化相互作用。
The fast technological advances of molecular tools have enabled us to uncover a new dimension hidden within parasites and their hosts: their microbiomes. Increasingly, parasitologists characterise host microbiome changes in the face of parasitic infections, revealing the potential of these microscopic fast-evolving entities to influence host-parasite interactions. However, most of the changes in host microbiomes seem to depend on the host and parasite species in question. Furthermore, we should understand the relative role of parasitic infections as microbiome modulators when compared with other microbiome-impacting factors (e.g., host size, age, sex). Here, we characterised the microbiome of a single intermediate host species infected by two parasites belonging to different phyla: the acanthocephalan Plagiorhynchus allisonae and a dilepidid
cestode, both infecting Transorchestia serrulata amphipods collected simultaneously from the same locality. We used the v4 hypervariable region of the 16S rRNA prokaryotic gene to identify the hemolymph bacterial community of uninfected, acanthocephalan-infected, and
cestode-infected amphipods, as well as the bacteria in the amphipods\' immediate environment and in the parasites infecting them. Our results show that parasitic infections were more strongly associated with differences in host bacterial community richness than amphipod size, presence of amphipod eggs in female amphipods, and even parasite load. Amphipods infected by acanthocephalans had the most divergent bacterial community, with a marked decrease in alpha diversity compared with
cestode-infected and uninfected hosts. In accordance with the species-specific nature of microbiome changes in parasitic infections, we found unique microbial taxa associating with hosts infected by each parasite species, as well as taxa only shared between a parasite species and their infected hosts. However, there were some bacterial taxa detected in all parasitised amphipods (regardless of the parasite species), but not in uninfected amphipods or the environment. We propose that shared bacteria associated with all hosts parasitised by distantly related helminths may be important either in helping host defences or parasites\' success, and could thus interact with host-parasite evolution.