There is growing interest in uncovering the viral diversity present in wild animal species. The remote Antarctic region is home to a wealth of uncovered microbial diversity, some of which is associated with its megafauna, including penguin species, the dominant avian biota. Penguins interface with a number of other biota in their roles as marine mesopredators and several species overlap in their ranges and habitats. To characterize the circular single-stranded viruses related to those in the phylum Cressdnaviricota from these environmental sentinel species, cloacal swabs (n = 95) were obtained from King Penguins in South Georgia, and congeneric Adélie Penguins, Chinstrap Penguins, and Gentoo Penguins across the South Shetland Islands and Antarctic Peninsula. Using a combination of high-throughput sequencing, abutting primers-based PCR recovery of circular genomic elements, cloning, and Sanger sequencing, we detected 97 novel sequences comprising 40 ssDNA viral genomes and 57 viral-like circular molecules from 45 individual penguins. We present their detection patterns, with Chinstrap Penguins harboring the highest number of new sequences. The novel Antarctic viruses identified appear to be host-specific, while one circular molecule was shared between sympatric Chinstrap and Gentoo Penguins. We also report viral genotype sharing between three adult-chick pairs, one in each Pygoscelid species. Sequence similarity network approaches coupled with Maximum likelihood phylogenies of the clusters indicate the 40 novel viral genomes do not fall within any known viral families and likely fall within the recently established phylum Cressdnaviricota based on their replication-associated protein sequences. Similarly, 83 capsid protein sequences encoded by the viruses or viral-like circular molecules identified in this study do not cluster with any of those encoded by classified viral groups. Further research is warranted to expand knowledge of the Antarctic virome and would help elucidate the importance of viral-like molecules in vertebrate host evolution.

中文翻译：

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南乔治亚岛和南极半岛四种企鹅物种中新型 Cressdnaviruses 和环状分子的鉴定和分布。

人们对揭示野生动物物种中存在的病毒多样性越来越感兴趣。遥远的南极地区拥有大量未发现的微生物多样性，其中一些与其巨型动物群有关，包括企鹅物种，这是主要的鸟类生物群。企鹅与许多其他生物群相互作用，作为海洋中食肉动物，并且几个物种的范围和栖息地重叠。为了表征与来自这些环境哨兵物种的Cressdnaviricota门中的病毒相关的圆形单链病毒，泄殖腔拭子 ( n= 95) 来自南乔治亚岛的王企鹅，以及横跨南设得兰群岛和南极半岛的同类阿德利企鹅、帽带企鹅和巴布亚企鹅。结合高通量测序、基于引物的环状基因组元件 PCR 回收、克隆和 Sanger 测序，我们从 45 只企鹅中检测到 97 个新序列，包括 40 个 ssDNA 病毒基因组和 57 个病毒样环状分子。我们展示了它们的检测模式，Chinstrap Penguins 拥有最多数量的新序列。发现的新型南极病毒似乎是宿主特异性的，而同域的帽带企鹅和 Gentoo 企鹅共享一个圆形分子。我们还报告了三对成年-小鸡之间的病毒基因型共享，每个 Pygoscelid 物种中都有一个。Cressdnaviricota基于它们的复制相关蛋白序列。同样，由本研究中鉴定的病毒或病毒样环状分子编码的 83 个衣壳蛋白序列与分类病毒组编码的任何衣壳蛋白序列都不聚类。需要进一步研究以扩大对南极病毒组的了解，并将有助于阐明病毒样分子在脊椎动物宿主进化中的重要性。