Xiang Jun, Fu Min, Hong Ni, Zhai Lifeng, Xiao Feng, Wang Guoping
State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China.
College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China.
Arch Virol. 2017 Dec;162(12):3907-3911. doi: 10.1007/s00705-017-3543-6. Epub 2017 Sep 11.
Alternaria fungi are important pathogens infecting a wide variety of organisms. Here, we report a novel double-stranded RNA (dsRNA) mycovirus named Alternaria botybirnavirus 1 (ABRV1) isolated from a phytopathogenic Alternaria sp. strain (SCFS-3) infecting a pear tree in China. ABRV1 has two dsRNA components (dsRNAs 1 and 2) with the sizes of 6,188 and 5,903 bp, containing two putative open reading frames encoding two polyproteins (202 and 192 kDa, respectively). The polyprotein encoded by ABRV1 dsRNA1 shares 41% amino acid (aa) sequence identity with the one encoded by dsRNA2 (instead of dsRNA1) of Sclerotinia sclerotiorum botybirnavirus 1 (SsBRV1). Conversely, the polyprotein encoded by ABRV1 dsRNA2 shares 46% aa sequence identity with the one (i.e., cap-pol fusion protein) encoded by SsBRV1 dsRNA1. ABRV1 has isometric spherical virus particles (~40 nm in diameter), putatively composed of the 60-, 70- and 80-kDa structural proteins. The genomic organization and phylogenetic analyses revealed that ABRV1 belongs to a newly proposed family "Botybirnaviridae", and to our knowledge, this is the first report of a botybirnavirus infecting an Alternaria sp. strain.
链格孢属真菌是感染多种生物体的重要病原体。在此，我们报告了一种从中国一株感染梨树的植物病原性链格孢属菌株（SCFS - 3）中分离出的新型双链RNA（dsRNA）真菌病毒，命名为链格孢葡萄孢双分病毒1（ABRV1）。ABRV1有两个dsRNA组分（dsRNAs 1和2），大小分别为6188和5903 bp，包含两个推定的开放阅读框，分别编码两种多聚蛋白（分别为202和192 kDa）。ABRV1 dsRNA1编码的多聚蛋白与核盘菌葡萄孢双分病毒1（SsBRV1）的dsRNA2（而非dsRNA1）编码的多聚蛋白氨基酸（aa）序列同一性为41%。相反，ABRV1 dsRNA2编码的多聚蛋白与SsBRV1 dsRNA1编码的多聚蛋白（即帽 - 聚合酶融合蛋白）氨基酸序列同一性为46%。ABRV1具有等轴对称球形病毒粒子（直径约40 nm），推测由60 kDa、70 kDa和80 kDa的结构蛋白组成。基因组结构和系统发育分析表明，ABRV1属于一个新提出的“葡萄孢双分病毒科”，据我们所知，这是关于感染链格孢属菌株的葡萄孢双分病毒的首次报道。
