Asgardarchaeota harbour many eukaryotic signature proteins and are widely considered to represent the closest archaeal relatives of eukaryotes. Whether similarities between Asgard archaea and eukaryotes extend to their viromes remains unknown. Here we present 20 metagenome-assembled genomes of Asgardarchaeota from deep-sea sediments of the basin off the Shimokita Peninsula, Japan. By combining a CRISPR spacer search of metagenomic sequences with phylogenomic analysis, we identify three family-level groups of viruses associated with Asgard archaea. The first group, verdandiviruses, includes tailed viruses of the class Caudoviricetes (realm Duplodnaviria); the second, skuldviruses, consists of viruses with predicted icosahedral capsids of the realm Varidnaviria; and the third group, wyrdviruses, is related to spindle-shaped viruses previously identified in other archaea. More than 90% of the proteins encoded by these viruses of Asgard archaea show no sequence similarity to proteins encoded by other known viruses. Nevertheless, all three proposed families consist of viruses typical of prokaryotes, providing no indication of specific evolutionary relationships between viruses infecting Asgard archaea and eukaryotes. Verdandiviruses and skuldviruses are likely to be lytic, whereas wyrdviruses potentially establish chronic infection and are released without host cell lysis. All three groups of viruses are predicted to play important roles in controlling Asgard archaea populations in deep-sea ecosystems.

Asgardarchaeota 含有许多真核生物特征蛋白，被广泛认为代表真核生物最接近的古菌亲属。Asgard 古细菌和真核生物之间的相似性是否延伸到它们的病毒组仍然未知。在这里，我们展示了来自日本下北半岛盆地深海沉积物的 20 个宏基因组组装的 Asgardarchaeota 基因组。通过将宏基因组序列的 CRISPR 间隔搜索与系统基因组分析相结合，我们确定了与 Asgard 古细菌相关的三个家族级病毒组。第一组，verdandiviruses，包括尾病毒类Caudoviricetes (realm Duplodnaviria )；第二种，skuldviruses，由预测为Varidnaviria领域的二十面体衣壳的病毒组成; 第三组，wyrdviruses，与之前在其他古细菌中发现的纺锤形病毒有关。这些 Asgard 古细菌病毒编码的蛋白质中，超过 90% 与其他已知病毒编码的蛋白质没有序列相似性。然而，所有三个提议的家族都由原核生物的典型病毒组成，没有提供感染 Asgard 古细菌和真核生物的病毒之间特定进化关系的迹象。Verdandiviruses 和 skuldviruses 可能会溶解，而 wyrdviruses 可能会建立慢性感染并在没有宿主细胞溶解的情况下释放。预计这三组病毒都将在控制深海生态系统中的 Asgard 古细菌种群中发挥重要作用。