Antarctic Fish Gill Viromes

Antarctica harbours some of the most isolated and extreme environments on Earth, concealing a largely unexplored fraction of the virosphere. Using meta-transcriptomics, we investigated the viromes of 11 groups of Antarctic fish collected from the Ross Sea region spanning the Perciformes, Gadiformes, and Scorpaeniformes, aiming to understand the evolutionary trajectories of viruses in these polar species. The continent's shift southward and cooling temperatures over 20 million years ago led to a reduction in biodiversity and subsequent adaptive radiation of marine fauna, particularly of notothenioid (Perciformes) fish. Despite the lower host species richness in polar regions, our study revealed a surprisingly complex virome diversity in Ross Sea fish, comparable to that of fish in more diverse and warmer marine environments. We observed instances of both virus-host co-divergence and host-switching events, particularly among notothenioid fish, suggesting a link between speciation and viral diversity. These findings emphasise the importance of understanding virus-host interactions in response to environmental shifts, especially in less diverse ecosystems vulnerable to the impacts of climate change and human activities.

南极洲拥有地球上最为偏远且极端的环境之一，隐匿着病毒圈（virosphere）中大量尚未被探索的区域。本研究采用元转录组学（meta-transcriptomics）技术，对采集自罗斯海区域、隶属于鲈形目（Perciformes）、鳕形目（Gadiformes）及鲉形目（Scorpaeniformes）的11组南极鱼类的病毒组（virome）进行了解析，旨在探究这些极地物种体内病毒的演化轨迹。2000万年前，南极洲向南漂移且气温持续下降，致使海洋生物多样性降低，随后海洋动物群发生适应性辐射，其中尤以隶属于鲈形目的南极鱼亚目（Notothenioidei）鱼类最为显著。尽管极地海域的宿主物种丰富度较低，但本研究揭示出罗斯海鱼类拥有出人意料的复杂病毒组多样性，其丰富程度可与物种更丰富、水温更高的海洋环境中的鱼类病毒组相媲美。研究团队观测到病毒-宿主共分化与宿主切换两类事件，尤其在南极鱼亚目鱼类中更为突出，这表明物种形成与病毒多样性之间存在关联。本研究结果凸显了解析病毒-宿主互作关系以响应环境变化的重要性，尤其是在那些易受气候变化与人类活动影响的低生物多样性生态系统中。