The search for viruses infecting fungi, or mycoviruses, has extended our knowledge about the diversity of RNA viruses, as exemplified by the discovery of polymycoviruses, a phylogenetic group of multisegmented RNA viruses with unusual forms. The genomic RNAs of known polymycoviruses, which show a phylogenetic affinity for animal positive-sense single-stranded RNA [(+)RNA] viruses such as caliciviruses, are comprised of four conserved segments with an additional zero to four segments. The double-stranded form of polymycovirus genomic RNA is assumed to be associated with a virally encoded protein (proline-alanine-serine-rich protein [PASrp]) in either of two manners: a capsidless colloidal form or a filamentous encapsidated form. Detailed molecular characterizations of polymycoviruses, however, have been conducted for only a few strains. Here, a novel polymyco-related virus named Hadaka virus 1 (HadV1), from the phytopathogenic fungus Fusarium oxysporum, was characterized. The genomic RNA of HadV1 consisted of an 11-segmented positive-sense RNA with highly conserved terminal nucleotide sequences. HadV1 shared the three conserved segments with known polymycoviruses but lacked the PASrp-encoding segment. Unlike the known polymycoviruses and encapsidated viruses, HadV1 was not pelleted by conventional ultracentrifugation, possibly due to the lack of PASrp. This result implied that HadV1 exists only as a soluble form with naked RNA. Nevertheless, the 11 genomic segments of HadV1 have been stably maintained through host subculturing and conidiation. Taken together, the results of this study revealed a virus with a potential novel virus lifestyle, carrying many genomic segments without typical capsids or PASrp-associated forms.

中文翻译：

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Hadaka病毒1：来自致病性真菌尖孢镰刀菌的无衣壳十一段正感单链RNA病毒。

寻找感染真菌或分枝杆菌病毒的病毒，已经扩展了我们对RNA病毒多样性的认识，例如发现了多分枝杆菌病毒（多系RNA病毒的系统发育群，具有异常形式）即为例证。已知的多分枝杆菌病毒的基因组RNA对动物正向单链RNA [（+）RNA]病毒（例如杯状病毒）显示出亲缘关系，它由四个保守片段组成，另外还有零至四个片段。假定多分枝病毒基因组RNA的双链形式与病毒编码的蛋白质（脯氨酸-富含丙氨酸-丝氨酸的蛋白质[PASrp]）相关，有两种方式：无衣壳的胶体形式或丝状的衣壳形式。然而，仅对少数菌株进行了多霉菌病毒的详细分子表征。这里，鉴定了尖孢镰刀菌。HadV1的基因组RNA由具有11个片段的正义RNA和高度保守的末端核苷酸序列组成。HadV1与已知的多粘菌病毒共享三个保守区段，但缺少PASrp编码区段。与已知的多霉菌病毒和衣壳病毒不同，HadV1不能通过常规超速离心沉淀，这可能是由于缺少PASrp所致。该结果暗示HadV1仅以裸露RNA的可溶形式存在。尽管如此，HadV1的11个基因组片段已通过宿主亚培养和整合而得以稳定维持。两者合计，这项研究的结果揭示了一种具有潜在的新型病毒生活方式的病毒，该病毒携带许多基因组片段，而没有典型的衣壳或与PASrp相关的形式。