Data_Sheet_1_Extreme Diversity of Mycoviruses Present in Isolates of Rhizoctonia solani AG2-2 LP From Zoysia japonica From Brazil.pdf

Zoysia japonica, in Brazil, is commonly infected by Rhizoctonia solani (R. solani) in humid and cool weather conditions. Eight isolates of R. solani, 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 in vitro 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 R. solani AG2-2 LP in South America.

在巴西，结缕草（Zoysia japonica）在潮湿凉爽的气候条件下，常受立枯丝核菌（Rhizoctonia solani，简称R. solani）侵染。研究人员从巴西圣保罗州3个县采集了8株立枯丝核菌分离株，这些分离株此前被鉴定为属于融合群AG2-2 LP，均采自带有大型病斑的样本，随后针对其携带的真菌病毒（mycoviruses）开展了调查。在所有样本中均检测到双链RNA（double-strand RNA，dsRNA）后，研究人员对体外培养菌丝体的去除核糖体RNA总RNA进行了RNA测序（RNA-Seq）分析。最终获得47条部分或完整的独特病毒RNA依赖的RNA聚合酶（RNA dependent-RNA polymerase，RdRp）序列，其中正链单链RNA病毒占比极高。经比对，这些序列与BLAST（Basic Local Alignment Search Tool）搜索得到的首个匹配序列差异显著，表明除1条与α分病毒属（alphapartitivirus）的立枯丝核菌双链RNA病毒2几乎完全匹配的序列外，其余序列均符合潜在新病毒物种的判定标准。令人意外的是，有4条大片段重叠群（contigs）对应的推定病毒RNA无法归类至数据库中已有的任何病毒进化枝，但未检测到与这些片段对应的DNA，证实了其病毒复制型本质。本研究是南美地区首次关于立枯丝核菌AG2-2 LP融合群中真菌病毒存在情况的报道。