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.

寄生于螺类的吸虫（Snail-borne trematodes）是一类规模庞大、种类多样，且在演化、生态与医学领域均具有重要意义的寄生虫类群，其常会对宿主施加强烈的选择压力，并导致宿主发病乃至死亡。即便如此，这类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同属螺类——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受到广泛关注，很大程度上得益于 Potamopyrgus antipodarum 与其可致宿主绝育的吸虫寄生虫 Microphallus livelyi 被开发为自然界中宿主-寄生虫协同进化互作研究的经典教科书模型。与之相对，栖息于河口生境、与淡水生境的 Potamopyrgus antipodarum 亲缘关系紧密的 P. estuarinus 与 Microphallus 吸虫之间的互作关系，目前仍鲜有研究。本研究首次发布了分别从 Potamopyrgus antipodarum 与 P. estuarinus 体内分离得到的 Microphallus 吸虫的注释转录组组装结果。本研究还利用这些转录组构建了基因组学资源，可为关注该类螺类-吸虫研究体系乃至其他同类体系的宿主-寄生虫协同进化、局部适应、分子演化与系统发育研究的科研人员提供广泛的研究支撑。对这两份 Microphallus 转录组的分析显示，这两种吸虫类群之间的遗传分化程度，高于寄生于不同种群 Potamopyrgus antipodarum 的 M. livelyi 之间的分化水平，这表明寄生于 P. estuarinus 的 Microphallus 代表了一个独特的演化支系。本研究同时提供了一组极具研究价值的候选基因，这些基因大概率参与了寄生感染过程以及对盐度胁迫的响应。