Data from: De novo transcriptome characterization of a sterilizing trematode parasite (Microphallus sp.) from two species of New Zealand snails

Snail-borne trematodes represent a large, diverse, and evolutionarily, ecologically, and medically important group of parasites, often imposing strong selection on their hosts and causing host morbidity and mortality. Even so, there are very few genomic and transcriptomic resources available for this important animal group. We help to fill this gap by providing transcriptome resources from trematode metacercariae infecting two congeneric snail species, Potamopyrgus antipodarum and P. estuarinus. This genus of New Zealand snails has gained prominence in large part through the development of P. antipodarum and its sterilizing trematode parasite Microphallus livelyi into a textbook model for host-parasite coevolutionary interactions in nature. By contrast, the interactions between Microphallus trematodes and P. estuarinus, an estuary-inhabiting species closely related to the freshwater P. antipodarum, are relatively unstudied. Here, we provide the first annotated transcriptome assemblies from Microphallus isolated from P. antipodarum and P. estuarinus. We also use these transcriptomes to produce genomic resources that will be broadly useful to those interested in host-parasite coevolution, local adaption, and molecular evolution and phylogenetics of this and other snail-trematode systems. Analyses of the two Microphallus transcriptomes revealed that the two trematode types are more genetically differentiated from one another than are M. livelyi infecting different populations of P. antipodarum, suggesting that the Microphallus infecting P. estuarinus represent a distinct lineage. We also provide a promising set of candidate genes likely involved in parasitic infection and response to salinity stress.

螺传吸虫（Snail-borne trematodes）是一类物种丰富、多样性极高，且在进化、生态与医学领域均具有重要意义的寄生虫类群，它们通常会对宿主施加强烈的选择压力，并引发宿主的发病与死亡。尽管如此，这一具有重要研究价值的动物类群，其可获取的基因组与转录组资源却极为匮乏。本研究通过获取寄生于两种近缘螺类——Potamopyrgus antipodarum与P. estuarinus——的吸虫囊蚴（trematode metacercariae）的转录组资源，填补了这一研究空白。该新西兰螺属类群之所以广受关注，很大程度上源于P. antipodarum及其专性寄生的莱氏微茎吸虫（Microphallus livelyi）被开发为自然界宿主-寄生虫共进化互作（host-parasite coevolutionary interactions）的经典教科书模型。与之形成鲜明对比的是，栖息于河口生境、与淡水螺P. antipodarum亲缘关系紧密的P. estuarinus，其与微茎属吸虫（Microphallus）之间的互作关系却鲜有研究。本研究首次发布了分别从P. antipodarum和P. estuarinus体内分离得到的微茎属吸虫的注释化转录组组装（annotated transcriptome assemblies）结果。本研究还基于上述转录组数据构建了基因组学资源，可为关注该类群及其他螺-吸虫系统的宿主-寄生虫共进化、本地适应（local adaption）、分子进化（molecular evolution）与系统发育学（phylogenetics）研究的科研人员提供广泛的研究支撑。对两种微茎属吸虫转录组的分析结果显示，这两类吸虫之间的遗传分化程度，高于分别寄生于不同种群P. antipodarum的M. livelyi之间的遗传分化，这表明寄生于P. estuarinus的微茎吸虫代表了一个独特的演化支系。本研究同时提供了一批极具研究潜力的候选基因集，这些基因大概率参与了寄生虫感染过程以及盐度胁迫（salinity stress）应答过程。