RNA病毒家族Picobirnaviridae传统上与陆生哺乳动物和鸟类的胃肠道系统有关,在动物粪便样本中检测到大多数病毒。脊椎动物的转录组学研究,无脊椎动物,微生物群落,和环境样本导致了该家族的基因组和系统发育多样性的巨大扩展。然而,小比尔病毒仍然分类不佳,只有一个属和三个物种被国际病毒分类委员会正式批准。此外,无法在实验室环境中培养小癌细胞病毒或在动物组织样本中分离它们,结合基因组中细菌遗传基序的存在,这表明这些病毒可能代表RNA噬菌体,而不是与动物感染有关。利用来自哺乳动物的2,286个小比尔病毒的数据集,鸟,爬行动物,鱼,无脊椎动物,微生物群落,和环境样本,我们确定了七个一致的系统发育簇,可能代表我们暂时命名为“Alpha-”的Picobirnavirus属,\'贝塔-\',\'Gamma-\',\'三角洲-\',\'Epsilon-\',\'Zeta-\',和\'Etapicobirnavirus\'。对病毒-宿主系统发育之间的拓扑一致性的统计分析表明,跨物种传播比任何其他RNA病毒家族都更加频繁。此外,细菌核糖体结合位点基序在Picobirnavirus基因组中的富集程度高于两组已建立的RNA噬菌体-Leviviricetes和Cystoviridae。总的来说,我们的发现支持了Picobirnaviridae具有细菌宿主的假设,并为这种高度多样化和普遍存在的RNA病毒家族提供了较低级别的分类学分类。
The RNA virus family Picobirnaviridae has traditionally been associated with the gastrointestinal systems of terrestrial mammals and birds, with the majority of viruses detected in animal stool samples. Metatranscriptomic studies of vertebrates, invertebrates, microbial communities, and environmental samples have resulted in an enormous expansion of the genomic and phylogenetic diversity of this family. Yet picobirnaviruses remain poorly classified, with only one genus and three species formally ratified by the International Committee of Virus Taxonomy. Additionally, an inability to culture picobirnaviruses in a laboratory setting or isolate them in animal tissue samples, combined with the presence of bacterial genetic motifs in their genomes, suggests that these viruses may represent RNA bacteriophage rather than being associated with animal infection. Utilising a data set of 2,286 picobirnaviruses sourced from mammals, birds, reptiles, fish, invertebrates, microbial communities, and environmental samples, we identified seven consistent phylogenetic clusters likely representing Picobirnavirus genera that we tentatively name \'Alpha-\', \'Beta-\', \'Gamma-\', \'Delta-\', \'Epsilon-\', \'Zeta-\', and \'Etapicobirnavirus\'. A statistical analysis of topological congruence between virus-host phylogenies revealed more frequent cross-species transmission than any other RNA virus family. In addition, bacterial ribosomal binding site motifs were more enriched in Picobirnavirus genomes than in the two groups of established RNA bacteriophage-the Leviviricetes and Cystoviridae. Overall, our findings support the hypothesis that the Picobirnaviridae have bacterial hosts and provide a lower-level taxonomic classification for this highly diverse and ubiquitous family of RNA viruses.