Biological invasions are among the biggest threats to freshwater biodiversity. This is increasingly relevant in the Murray–Darling Basin, Australia, particularly since the introduction of the common carp (Cyprinus carpio). This invasive species now occupies up to ninety per cent of fish biomass, with hugely detrimental impacts on native fauna and flora. To address the ongoing impacts of carp, cyprinid herpesvirus 3 (CyHV-3) has been proposed as a potentially effective biological control agent. Crucially, however, it is unknown whether CyHV-3 and other cyprinid herpesviruses already exist in the Murray–Darling. Further, little is known about those viruses that naturally occur in wild freshwater fauna, and the frequency with which these viruses jump species boundaries. To document the evolution and diversity of freshwater fish viromes and better understand the ecological context to the proposed introduction of CyHV-3, we performed a meta-transcriptomic viral survey of invasive and native fish across the Murray–Darling Basin, covering over 2,200 km of the river system. Across a total of thirty-six RNA libraries representing ten species, we failed to detect CyHV-3 nor any closely related viruses. Rather, meta-transcriptomic analysis identified eighteen vertebrate-associated viruses that could be assigned to the Arenaviridae, Astroviridae, Bornaviridae, Caliciviridae, Coronaviridae, Chuviridae, Flaviviridae, Hantaviridae, Hepeviridae, Paramyxoviridae, Picornaviridae, Poxviridae, Reoviridae and Rhabdoviridae families, and a further twenty-seven that were deemed to be associated with non-vertebrate hosts. Notably, we revealed a marked lack of viruses that are shared among invasive and native fish sampled here, suggesting that there is little virus transmission from common carp to native fish species, despite co-existing for over fifty years. Overall, this study provides the first data on the viruses naturally circulating in a major river system and supports the notion that fish harbour a large diversity of viruses with often deep evolutionary histories.

中文翻译：

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宏基因组测序显示澳大利亚墨累-达令盆地的本地淡水鱼和入侵淡水鱼之间缺乏病毒交换


生物入侵是淡水生物多样性面临的最大威胁之一。这在澳大利亚墨累-达令盆地越来越重要，特别是自从引入鲤鱼（Cyprinus carpio）以来。这种入侵物种目前占据了鱼类生物量的百分之九十，对本地动植物群产生了巨大的有害影响。为了解决鲤鱼的持续影响，鲤鱼疱疹病毒 3 (CyHV-3) 被提议作为一种潜在有效的生物防治剂。然而，至关重要的是，目前尚不清楚墨累-达令河中是否已经存在 CyHV-3 和其他鲤科疱疹病毒。此外，人们对野生淡水动物群中自然存在的病毒以及这些病毒跨越物种界限的频率知之甚少。为了记录淡水鱼病毒组的进化和多样性，并更好地了解拟议引入 CyHV-3 的生态背景，我们对墨累-达令盆地的入侵鱼类和本地鱼类进行了宏转录组病毒调查，覆盖范围超过 2,200 平方公里。河流系统。在代表 10 个物种的总共 36 个 RNA 文库中，我们未能检测到 CyHV-3 或任何密切相关的病毒。相反，宏转录组学分析确定了 18 种与脊椎动物相关的病毒，这些病毒可归属于沙粒病毒科、星状病毒科、博尔病毒科、杯状病毒科、冠状病毒科、楚病毒科、黄病毒科、汉坦病毒科、肝炎病毒科、副粘病毒科、小核糖核酸病毒科、痘病毒科、呼肠孤病毒科和弹状病毒科，以及进一步二十七个被认为与非脊椎动物宿主有关。 值得注意的是，我们发现这里采样的入侵鱼类和本地鱼类之间明显缺乏共享的病毒，这表明尽管共存了五十多年，但从鲤鱼到本地鱼类之间几乎没有病毒传播。总体而言，这项研究提供了有关在主要河流系统中自然传播的病毒的第一批数据，并支持了鱼类携带大量具有深厚进化历史的病毒多样性的观点。