ATP-Binding Cassette (ABC) transporters are proteins that actively mediate the transport of a wide variety of molecules, including drugs. Thus, in parasitology, ABC transporters have gained attention as potential targets for therapeutic drugs. Among the parasitic Platyhelminthes, ABC transporters have been identified and classified in a few species of Trematoda and Cestoda but not in Monogenea. Monogeneans are mainly ectoparasites of marine and freshwater fish, although they can also be found on other aquatic organisms. Severe epizootics caused by monogeneans have been reported around the world, mainly in confined and/or overcrowded fish. The purpose of this study was to identify the ABC transporters in four species of monogeneans (Gyrodactylus salaris, Protopolystoma xenopodis, Eudiplozoon nipponicum and Neobenedenia melleni) for which genomic resources are publicly available. For comparative purposes, ABC transporters were also identified in endoparasitic (Schistosoma mansoni and Echinococcus granulosus) and free-living (Macrostomun lignano and Schmidtea mediterranea) platyhelminths. Thirty-two putative ABC transporters were identified in the genome of G. salaris, 40 in the genome of P. xenopodis, 46 in the transcriptome of E. nipponicum and 9 in a rather limited ESTs set available for N. melleni. Of the eight ABC subfamilies (A–H) known in metazoans, subfamily H was the only one not found in any monogenean species. In contrast, ABCC was the best represented subfamily. Phylogenetic analyses showed a few cases of one-to-one orthologous relationships, which agree with results from other metazoan species. We found some monogenean ABC members related to subfamilies B, C and G involved in drug resistance in humans. This information may be useful for future functional studies on ABC transporters in monogeneans.

ATP结合盒（ABC）转运蛋白是可主动介导包括药物在内的多种分子转运的蛋白质。因此，在寄生虫学中，ABC转运蛋白已成为治疗药物的潜在靶点。在寄生的鸭嘴兽中，ABC转运蛋白已在Trematoda和Cestoda的少数物种中被识别和分类，而在Monogenea中则没有。单基因菌主要是海水和淡水鱼类的外寄生物，尽管它们也可以在其他水生生物中发现。在世界范围内已经报道了由单基因引起的严重的动物流行病，主要发生在密闭和/或拥挤的鱼类中。这项研究的目的是确定在四种单殖吸虫的ABC转运蛋白（三代虫salaris，Protopolystoma xenopodis，其基因组资源可公开获得的Eudiplozoon nipponicum和Neobenedenia melleni。为了进行比较，还在内寄生虫（曼氏血吸虫和细粒棘球E虫）和自由活动性（大梭菌木虱和嗜中叶Schmidtea mediterranea）的蠕虫中鉴定了ABC转运蛋白。三十二个推定的ABC转运中的基因组中鉴定了G. salaris，40中的基因组P. xenopodis，46的转录E. nipponicum在相当有限的EST和9设置可供N. melleni。在后生动物中已知的八个ABC亚科（A–H）中，H亚科是在任何单基因物种中均未发现的唯一一个。相反，ABCC是代表性最好的亚科。系统发育分析显示了少数一对一的直系同源关系，与其他后生物种的结果一致。我们发现一些与亚家族B，C和G有关的单基因ABC成员参与了人类的耐药性。此信息可能对单基因ABC转运蛋白的未来功能研究有用。