Bastos Gomes Giana, Miller Terrence L, Vaughan David B, Jerry Dean R, McCowan Christina, Bradley Tracey L, Hutson Kate S
Marine and Aquaculture Sciences, College of Science and Engineering and Centre for Sustainable Tropical Fisheries and Aquaculture, James Cook University, Townsville, 4811, QLD, Australia.
Marine and Aquaculture Sciences, College of Science and Engineering and Centre for Sustainable Tropical Fisheries and Aquaculture, James Cook University, Townsville, 4811, QLD, Australia; Fish Health Laboratory, Department of Fisheries Western Australia, South Perth 6151, WA, Australia.
Vet Parasitol. 2017 Apr 15;237:8-16. doi: 10.1016/j.vetpar.2017.03.004. Epub 2017 Mar 6.
Parasitic Chilodonella species, Chilodonella piscicola and Chilodonella hexasticha, cause considerable economic losses globally to freshwater farmed fish production. Some genetic studies of Chilodonella spp. have indicated that many species within the genus may form cryptic species complexes. To understand the diversity of Chilodonella spp. infecting Australian freshwater farmed fish, specimens were isolated from infected barramundi (Lates calcarifer) and Murray cod (Maccullochella peelii) from fish farms in tropical north Queensland (QLD), temperate Victoria (Vic) and New South Wales (NSW) for genetic and morphological analysis. Parasites were stained and measured for morphological description and comparative phylogenetic analyses were performed using the mitochondrial small subunit (mtSSU) rDNA marker. Morphological analyses revealed four distinct morphotypes of Chilodonella infecting farmed barramundi and Murray Cod. Three putative species were isolated from barramundi (Chilodonella hexasticha, C. acuta and C. uncinata) and one from Murray cod (C. piscicola). However, phylogenetic analyses detected only three distinct genotypes, with the putative C. hexasticha and C. piscicola sharing 100% sequence identity. This suggests that Australian isolates of C. hexasticha and C. piscicola could represent the same species and may exhibit phenotypic plasticity. Further molecular analysis, including isolates from the type localities, should be performed to support or refute the synonymy of these species.
寄生性的斜管虫属物种，如鱼斜管虫（Chilodonella piscicola）和六棘斜管虫（Chilodonella hexasticha），在全球范围内给淡水养殖鱼类生产造成了巨大的经济损失。一些关于斜管虫属的遗传学研究表明，该属内的许多物种可能构成隐存种复合体。为了解感染澳大利亚淡水养殖鱼类的斜管虫属物种的多样性，从热带北昆士兰（QLD）、温带维多利亚（Vic）和新南威尔士（NSW）的养鱼场中受感染的尖吻鲈（Lates calcarifer）和墨瑞鳕（Maccullochella peelii）中分离出样本，进行遗传学和形态学分析。对寄生虫进行染色和测量以进行形态学描述，并使用线粒体小亚基（mtSSU）rDNA标记进行比较系统发育分析。形态学分析揭示了感染养殖尖吻鲈和墨瑞鳕的四种不同形态型的斜管虫。从尖吻鲈中分离出三个假定物种（六棘斜管虫、尖锐斜管虫和钩状斜管虫），从墨瑞鳕中分离出一个（鱼斜管虫）。然而，系统发育分析仅检测到三种不同的基因型，假定的六棘斜管虫和鱼斜管虫共享100%的序列同一性。这表明澳大利亚的六棘斜管虫和鱼斜管虫分离株可能代表同一物种，并且可能表现出表型可塑性。应进行进一步的分子分析，包括来自模式产地的分离株，以支持或反驳这些物种的同义性。
