Li Wei, Zhang Haotian, Shu Yan, Cao Shulin, Sun Haiyan, Zhang Aixiang, Chen Huaigu
Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Jiangsu, Nanjing, 210014, China; Jiangsu Co-Innovation Centre for Modern Production Technology of Grain Crops, Yangzhou University, Jiangsu, Yangzhou, 225009, China.
Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Jiangsu, Nanjing, 210014, China; Hubei Collaborative Innovation Centre for Grain Industry, Yangtze University, Hubei, Jingzhou, 434025, China.
Virus Res. 2021 May;297:198368. doi: 10.1016/j.virusres.2021.198368. Epub 2021 Mar 5.
Rhizoctonia cerealis (teleomorph Ceratobasidium cereale) is a soil-borne plant pathogenic fungus that can cause sharp eyespot in wheat or yellow patch in grasses. In this study, 21 new endornavirus genomes were obtained from five R. cerealis strains through the high-throughput sequencing of viral double-stranded RNA. Eighteen viruses were identified as Alphaendornavirus, and three viruses were identified as new species of Betaendornavirus on the basis of the phylogenetic analysis of the deduced amino acid sequences of RNA-dependent RNA polymerase. Notably, 12 of the new alphaendornaviruses could encode two open reading frames (ORFs), which were a rare feature of Endornaviridae. The amino acid sequences encoded by ORF2 from different endornaviruses had very low identity, and their functions and evolution origins remained unclear. Different endornavirus species with remarkably different genome structures could be found in the same R. cerealis strain. This study indicated that endornaviruses are common in R. cerealis and display wide diversity. Betaendornaviruses were found in R. cerealis, and a new species was proposed. This study is the first to report that the endornaviruses from R. cerealis can encode two ORFs and enhances our understanding of the viruses in the Endornaviridae family.
禾谷丝核菌（有性型为禾谷角担菌）是一种土传植物病原真菌，可引起小麦的纹枯病或禾本科植物的黄斑病。在本研究中，通过对病毒双链RNA进行高通量测序，从5株禾谷丝核菌菌株中获得了21个新的内质网病毒基因组。基于RNA依赖的RNA聚合酶推导氨基酸序列的系统发育分析，18种病毒被鉴定为α内质网病毒，3种病毒被鉴定为β内质网病毒的新物种。值得注意的是，12种新的α内质网病毒可编码两个开放阅读框（ORF），这是内质网病毒科的一个罕见特征。来自不同内质网病毒的ORF2编码的氨基酸序列同一性非常低，其功能和进化起源尚不清楚。在同一株禾谷丝核菌中可发现具有显著不同基因组结构的不同内质网病毒物种。本研究表明内质网病毒在禾谷丝核菌中很常见且具有广泛的多样性。在禾谷丝核菌中发现了β内质网病毒，并提出了一个新物种。本研究首次报道禾谷丝核菌的内质网病毒可编码两个ORF，增进了我们对内质网病毒科中病毒的了解。
