Grimwood Rebecca M, Waller Stephanie J, Wierenga Janelle R, Lim Lauren, Dubrulle Jérémy, Holmes Edward C, Geoghegan Jemma L
Department of Microbiology and Immunology, University of Otago, Dunedin 9016, New Zealand.
Sydney Institute for Infectious Diseases, School of Medical Sciences, The University of Sydney, Camperdown, NSW 2006, Australia.
Virus Evol. 2024 Jul 11;10(1):veae050. doi: 10.1093/ve/veae050. eCollection 2024.
Antarctica harbours some of the most isolated and extreme environments on Earth, concealing a largely unexplored and unique component of the global animal virosphere. To understand the diversity and evolutionary histories of viruses in these polar species, we determined the viromes of gill metatranscriptomes from 11 Antarctic fish species with 248 samples collected from the Ross Sea region spanning the Perciformes, Gadiformes, and Scorpaeniformes orders. The continent's shift southward and cooling temperatures >20 million years ago led to a reduction in biodiversity and subsequent radiation of some marine fauna, such as the notothenioid fishes. Despite decreased host species richness in polar regions, we revealed a surprisingly complex virome diversity in Ross Sea fish, with the types and numbers of viruses per host species and individuals sampled comparable to that of fish in warmer marine environments with higher host community diversity. We also observed a higher number of closely related viruses likely representing instances of recent and historic host-switching events among the Perciformes (all notothenioids) than in the Gadiformes, suggesting that rapid speciation events within this order generated closely related host species with few genetic barriers to cross-species transmission. Additionally, we identified novel genomic variation in an arenavirus with a split nucleoprotein sequence containing a stable helical structure, indicating potential adaptation of viral proteins to extreme temperatures. These findings enhance our understanding of virus evolution and virus-host interactions in response to environmental shifts, especially in less diverse ecosystems that are more vulnerable to the impacts of anthropogenic and climate changes.
南极洲拥有地球上一些最为孤立和极端的环境，隐藏着全球动物病毒圈中很大程度上未被探索且独特的部分。为了解这些极地物种中病毒的多样性和进化史，我们测定了来自11种南极鱼类鳃部元转录组的病毒组，共采集了248个样本，样本来自罗斯海区域，涵盖鲈形目、鳕形目和鲉形目。2000多万年前该大陆向南移动以及气温下降导致生物多样性减少，随后一些海洋动物群（如南极鱼科鱼类）辐射演化。尽管极地地区宿主物种丰富度降低，但我们发现罗斯海鱼类的病毒组多样性惊人地复杂，每个宿主物种和所采样个体的病毒类型和数量与宿主群落多样性更高的温暖海洋环境中的鱼类相当。我们还观察到，鲈形目（所有南极鱼科鱼类）中密切相关病毒的数量比鳕形目中更多，这可能代表了近期和历史上宿主转换事件的实例，表明该目中的快速物种形成事件产生了亲缘关系密切的宿主物种，跨物种传播的遗传障碍较少。此外，我们在一种沙粒病毒中发现了新的基因组变异，其核蛋白序列分裂，含有稳定的螺旋结构，表明病毒蛋白可能适应极端温度。这些发现增进了我们对病毒进化以及病毒 - 宿主相互作用如何响应环境变化的理解，特别是在生物多样性较低、更容易受到人为和气候变化影响的生态系统中。
