Plant Virology Laboratory, Instituto Biológico, São Paulo, Brazil.
Department of Life Science and System Biology, University of Turin, Turin, Italy.
Front Cell Infect Microbiol. 2019 Jul 12;9:244. doi: 10.3389/fcimb.2019.00244. eCollection 2019.
, in Brazil, is commonly infected by () in humid and cool weather conditions. Eight isolates of , previously identified as belonging to the AG2-2 LP anastomosis group, isolated from samples from large path symptoms, were collected from three counties in São Paulo state (Brazil) and investigated for the presence of mycoviruses. After detection of double-strand RNA (dsRNA) in all samples, RNA_Seq analysis of ribosomal RNA-depleted total RNA from cultivated mycelia was performed. Forty-seven partial or complete viral unique RNA dependent-RNA polymerase (RdRp) sequences were obtained with a high prevalence of positive sense ssRNA viruses. Sequences were sufficiently different from the first match in BLAST searches suggesting that they all qualify as possible new viral species, except for one sequence showing an almost complete match with Rhizoctonia solani dsRNA virus 2, an alphapartitivirus. Surprisingly four large contigs of putative viral RNA could not be assigned to any existing clade of viruses present in the databases, but no DNA was detected corresponding to these fragments confirming their viral replicative nature. This is the first report on the occurrence of mycoviruses in AG2-2 LP in South America.
在巴西， 通常在潮湿和凉爽的天气条件下被 () 感染。从巴西圣保罗州三个县的大病理症状样本中收集了 8 株先前鉴定为属于 AG2-2 LP 吻合组的 ，并调查了其是否存在真菌病毒。在所有样本中检测到双链 RNA(dsRNA)后，对从培养的菌丝体中去除核糖体 RNA 的总 RNA 进行了 RNA_Seq 分析。从 中获得了 47 个部分或完整的病毒独特 RNA 依赖性 RNA 聚合酶(RdRp)序列，阳性单链 RNA 病毒的阳性率很高。序列在 BLAST 搜索中的首次匹配差异很大，表明它们都有资格成为可能的新病毒种，除了一个序列与 Rhizoctonia solani dsRNA virus 2（一种 alfapartitivirus）几乎完全匹配。令人惊讶的是，无法将四个推定的病毒 RNA 大片段分配给数据库中存在的任何现有病毒群，但没有检测到与这些片段相对应的 DNA，证实了它们的病毒复制性质。这是在南美的 AG2-2 LP 中首次报道真菌病毒的发生。
