Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Plant Protection, South China Agricultural University, Guangzhou, 510642, China.
Institute of Plant Protection, Jiangxi Academy of Agricultural Sciences, Nanchang, 330200, China.
Arch Virol. 2024 Mar 22;169(4):78. doi: 10.1007/s00705-024-06009-3.
Mycoviruses are viruses that infect fungi and oomycetes. They are widespread in all major groups of plant-pathogenic fungi and oomycetes. To date, only the full genome of dsRNA mycoviruses and the contigs of positive-sense single-stranded RNA (+ssRNA) mycoviruses have been reported in Ustilaginoidea virens, which is the notorious causal agent of rice false smut (RFS). Here, we report the molecular characterization of a novel +ssRNA mycovirus, Ustilaginoidea virens narnavirus 4 (UvNV4), isolated from U. virens strain Uv418. UvNV4 has a genome of 3,131 nucleotides (nt) and possesses an open reading frame (ORF) predicted to encode an RNA-dependent RNA polymerase (RdRp) of 1,017 amino acids (aa) sequence with a molecular mass of 116.6 kDa. BLASTp analysis revealed that the RdRp showed 50.34% aa sequence identity to that of the previously described Zhangzhou Narna tick virus 1. Phylogenetic analysis indicated that UvNV4 is closely related to members of the family Narnaviridae. Taken together, these results clearly demonstrate that UvNV4 is a novel +ssRNA virus infecting U. virens.
真菌病毒是感染真菌和卵菌的病毒。它们广泛存在于所有主要的植物病原真菌和卵菌类群中。迄今为止，只有 dsRNA 真菌病毒的全基因组和正单链 RNA(+ssRNA)真菌病毒的连续序列在 Ustilaginoidea virens 中被报道过，它是水稻假黑粉病（RFS）的臭名昭著的病原体。在这里，我们报告了一种新型的+ssRNA 真菌病毒 Ustilaginoidea virens narnavirus 4（UvNV4）的分子特征，该病毒是从 U. virens 菌株 Uv418 中分离出来的。UvNV4 的基因组为 3131 个核苷酸（nt），具有一个开放阅读框（ORF），预测编码一个 1017 个氨基酸（aa）序列的 RNA 依赖性 RNA 聚合酶（RdRp），分子量为 116.6 kDa。BLASTp 分析显示，RdRp 的 aa 序列与先前描述的 Zhangzhou Narna tick virus 1 有 50.34%的同源性。系统发育分析表明，UvNV4 与 Narnaviridae 家族的成员密切相关。综上所述，这些结果清楚地表明 UvNV4 是一种感染 U. virens 的新型+ssRNA 病毒。
