Here, we describe a tripartite circular single-stranded (ss) DNA mycovirus, named Fusarium graminearum gemytripvirus 1 (FgGMTV1). The genome of FgGMTV1 comprises three circular ssDNA segments (DNA-A, DNA-B, and DNA-C). Sequence alignments and phylogenetic analyses showed that FgGMTV1 is nested within the family Genomoviridae. We also constructed the first infectious DNA clones of a DNA mycovirus. Our results show that DNA-A and DNA-B are mutually interdependent for their replication and are associated with severely reduced colony growth and hypovirulence. DNA-C relies on DNA-A and DNA-B for replication and is necessary for the recovery of abnormal fungal phenotypes. DNA-C also enhances the accumulation of viral DNA in infected fungi and permits stable colonization and easy transmission via conidia. This is the first multipartite DNA virus isolated from a fungus. Our phylogenetic analyses also suggest that the multipartite genome of FgGMTV1 may have evolved from a monopartite genome of an ancient genomovirus.

在这里，我们描述了一个名为Fusarium graminearum gemytripvirus 1（FgGMTV1）的三方圆形单链（ss）DNA支原体病毒。FgGMTV1的基因组包含三个环状ssDNA片段（DNA-A，DNA-B和DNA-C）。序列比对和系统发育分析表明，FgGMTV1嵌套在Genomoviridae家族中。我们还构建了DNA真菌病毒的第一个传染性DNA克隆。我们的结果表明，DNA-A和DNA-B的复制相互依赖，并与菌落生长和低毒力严重降低有关。DNA-C依赖于DNA-A和DNA-B进行复制，并且是恢复异常真菌表型所必需的。DNA-C还可以增强病毒DNA在受感染真菌中的积累，并可以稳定定居并易于通过分生孢子传播。这是从真菌中分离出的第一种多部分DNA病毒。我们的系统发育分析还表明，FgGMTV1的多部分基因组可能已经从古老的基因病毒的单部分基因组进化而来。