Quiles Adrien, Rigaud Thierry, Wattier Rémi A, Grabowski Michal, Bacela Spychalska Karolina
Université Bourgogne Franche-Comté, Laboratoire Biogéosciences, UMR CNRS 6282, 6 Boulevard Gabriel, 21000 Dijon, France.
Department of Invertebrate Zoology and Hydrobiology, University of Lodz, 12/16 Banacha Street, 90-237, Lodz, Poland.
Int J Parasitol Parasites Wildl. 2021 Jan 15;14:121-129. doi: 10.1016/j.ijppaw.2021.01.004. eCollection 2021 Apr.
Parasites and other symbionts deeply influence host organisms, and no living organism can be considered to have evolved independent of its symbionts. The first step towards understanding symbiotic influences upon host organisms is a strong supporting knowledge of parasite/symbiont diversity. Parasites of freshwater amphipods are diverse, with Microsporidia being a major group. These intracellular parasites impact gammarid fitness in different ways, ranging from reduced fitness to increased fecundity. Many Microsporidia have been recorded using molecular data, with multiple taxa pending formal taxonomic description. While some parasites are common, others are known only through sporadic records of single infections. In this study, we focus on rare/sporadic microsporidian infections within , a host species complex with a high level of endemism. In addition to enriching our knowledge on Microsporidia parasite diversity in amphipod hosts, we test whether these symbionts are specific to or if they are the same taxa infecting other gammarid species. Of 2231 hosts from 87 sites, we catalogued 29 sequences of "rare" Microsporidia clustering into 19 haplogroups. These haplogroups cluster into 11 lineages: four pre-described taxa (, and ) and seven 'Molecular Operational Taxonomic Units', which are known from previously published studies to infect other European amphipod species. Our study significantly widens the geographic range of these Microsporidia and expands the known spectrum of hosts infected. Our results suggest that these parasites are ancient infections of European gammarids. For some host-parasite systems, we hypothesize that the common parasite ancestors that infected the hosts' common ancestors, diversified alongside host diversification. For others, we observe Microsporidia taxa with wide host ranges that do not follow host phylogeny.
寄生虫和其他共生体对宿主生物有着深远影响，没有任何一种生物的进化可以被认为是独立于其共生体的。了解共生体对宿主生物影响的第一步是对寄生虫/共生体多样性有扎实的支撑性知识。淡水双足类动物的寄生虫种类繁多，微孢子虫是主要类群。这些细胞内寄生虫以不同方式影响钩虾的适应性，从降低适应性到提高繁殖力。利用分子数据已记录了许多微孢子虫，还有多个分类单元有待正式的分类描述。虽然一些寄生虫很常见，但其他寄生虫仅通过单次感染的零星记录为人所知。在本研究中，我们聚焦于一种具有高度特有性的宿主物种复合体中的罕见/零星微孢子虫感染。除了丰富我们对双足类宿主中微孢子虫寄生虫多样性的认识外，我们还测试这些共生体是否特定于该宿主物种复合体，或者它们是否是感染其他钩虾物种的相同分类单元。在来自87个地点的2231个宿主中，我们编目了29个“罕见”微孢子虫序列，这些序列聚为19个单倍型类群。这些单倍型类群聚为11个谱系：四个先前描述的分类单元（、和）以及七个“分子操作分类单元”，从先前发表的研究可知它们感染其他欧洲双足类物种。我们的研究显著拓宽了这些微孢子虫的地理分布范围，并扩大了已知的受感染宿主谱。我们的结果表明这些寄生虫是欧洲钩虾的古老感染。对于一些宿主 - 寄生虫系统，我们推测感染宿主共同祖先的常见寄生虫祖先随着宿主的多样化而多样化。对于其他系统，我们观察到微孢子虫分类单元具有广泛的宿主范围，并不遵循宿主系统发育。
