Molecular characterization of a novel mycovirus of the family Tymoviridae isolated from the plant pathogenic fungus Fusarium graminearum
Molecular characterization of a novel mycovirus of the family Tymoviridae isolated from the plant pathogenic fungus Fusarium graminearum
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DOI：
10.1016/j.virol.2015.12.004
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发表时间：
2016-02-01
期刊：
影响因子：
3.7
通讯作者：
Guo, Lihua
中科院分区：
文献类型：
--
作者：
Li, Pengfei;Lin, Yanhong;Guo, Lihua
我们从植物病原真菌F.graminearum菌株SX64中分离到一种新的真菌病毒--禾谷镰刀菌MycoymoVirus 1(FgMTV1/SX64)，该病毒与Tymoridae家族成员有亲缘关系。测定了FgMTV1/SX64株7863个核苷酸的完整序列，其中不包括PolyA尾部。据预测，FgMTV1/SX64的基因组包含4个开放阅读框架(ORF)。最大的ORF1全长6723个核苷酸(NT)，编码2242个氨基酸(AA)，包含正链RNA病毒复制相关蛋白(RPS)的甲基转移酶(MTR)、类型病毒内肽酶(Pro)、病毒RNA解旋酶(Hel)和RNA依赖RNA聚合酶(RdRp)四个保守结构域。ORF2-4推测编码三种假定的小蛋白，但它们的功能尚不清楚。基于推测的RP蛋白和三个保守结构域(MTR、Hel和RdRp)的序列比对和系统发育分析表明，FgMTV1/SX64与Tymoviridae家族的病毒关系最密切，但有明显的分支。虽然FgMTV1/SX64感染对其寄主菌株SX64的产孢量、生物量和致病力影响很小或没有影响，但它对菌落生长速度、菌落直径和脱氧雪腐镰刀菌烯醇(DON)的产生有显著影响。这是从植物病原真菌中分离到的一种类似胸腺的真菌病毒的第一个分子特征。据推测，霉菌病毒FgMTV1/SX64是Tymoridae科新提出的菌丝病毒谱系中具有代表性的成员。(C)2015 Elsevier Inc.保留所有权利。
We isolated a novel mycovirus, Fusarium graminearum mycotymovirus 1 (FgMTV1/SX64), which is related to members of the family Tymoviridae, from the plant pathogenic fungus F. graminearum strain SX64. The complete 7863 nucleotide sequence of FgMTV1/SX64, excluding the poly (A) tail, was determined. The genome of FgMTV1/SX64 is predicted to contain four open reading frames (ORFs). The largest ORF1 is 6723 nucleotides (nt) in length and encodes a putative polyprotein of 2242 amino acids (aa), which contains four conserved domains, a methyltransferase (Mtr), tymovirus endopeptidase (Pro), viral RNA helicase (Hel), and RNA-dependent RNA polymerase (RdRp), of the replication-associated proteins (RPs) of the positive-strand RNA viruses. ORFs 2-4 putatively encode three putative small hypothetical proteins, but their functions are still unknown. Sequence alignments and phylogenetic analyses based on the putative RP protein and the three conserved domains (Mtr, Hel and RdRp) showed that FgMTV1/SX64 is most closely related to, but distinctly branched from, the viruses from the family Tymoviridae. Although FgMTV1/SX64 infection caused mild or no effect on conidia production, biomass and virulence of its host F. graminearum strain SX64, its infection had significant effects on the growth rate, colony diameter and deoxynivalenol (DON) production. This is the first molecular characterization of a tymo-like mycovirus isolated from a plant pathogenic fungus. It is proposed that the mycovirus FgMTV1/SX64 is a representative member of new proposed lineage Mycotymovirus in the family Tymoviridae. (C) 2015 Elsevier Inc. All rights reserved.