Zhao Hongda, Zhang Ruixuan, Wu Junyi, Meng Lingjie, Okazaki Yusuke, Hikida Hiroyuki, Ogata Hiroyuki
Chemical Life Science, Institute for Chemical Research, Kyoto University, Gokasho, Uji 611-0011, Japan.
Virus Evol. 2023 Oct 31;9(2):vead064. doi: 10.1093/ve/vead064. eCollection 2023.
Most fungal viruses are RNA viruses, and no double-stranded DNA virus that infects fungi is known to date. A recent study detected DNA polymerase genes that originated from large dsDNA viruses in the genomes of basal fungi, suggestive of the existence of dsDNA viruses capable of infecting fungi. In this study, we searched for viral infection signatures in chromosome-level genome assemblies of the arbuscular mycorrhizal fungus . We identified a continuous 1.5-Mb putative viral region on a chromosome in strain 4401. Phylogenetic analyses revealed that the viral region is related to viruses in the family of the phylum . This viral region was absent in the genomes of four other strains and had fewer signals of fungal transposable elements than the other genomic regions, suggesting a recent and single insertion of a large dsDNA viral genome in the genome of this fungal strain. We also incidentally identified viral-like sequences in the genome assembly of the sea slug that are evolutionally close to the 1.5-Mb putative viral region. In conclusion, our findings provide strong evidence of the recent infection of the fungus by a dsDNA virus.
大多数真菌病毒是RNA病毒，迄今为止，尚未发现感染真菌的双链DNA病毒。最近的一项研究在基部真菌的基因组中检测到源自大型双链DNA病毒的DNA聚合酶基因，这表明存在能够感染真菌的双链DNA病毒。在本研究中，我们在丛枝菌根真菌的染色体水平基因组组装中寻找病毒感染特征。我们在菌株4401的一条染色体上鉴定出一个连续的1.5兆碱基推定病毒区域。系统发育分析表明，该病毒区域与门的科中的病毒有关。该病毒区域在其他四个菌株的基因组中不存在，并且与其他基因组区域相比，真菌转座元件的信号更少，这表明在该真菌菌株的基因组中最近单次插入了一个大型双链DNA病毒基因组。我们还偶然在海蛞蝓的基因组组装中鉴定出与1.5兆碱基推定病毒区域进化关系密切的病毒样序列。总之，我们的发现为双链DNA病毒最近感染该真菌提供了有力证据。
