稻瘟菌双分病毒MoPV2特性研究

稻瘟病是稻瘟菌引起的一种世界性病害,每年造成水稻大幅减产。真菌病毒是指能够在真菌体内进行复制和繁殖的病毒,可以作为生物防治的资源。本实验从发病的水稻叶片上采用单孢分离的方法获得纯化培养的稻瘟菌菌株YC13。菌株YC13携带多条dsRNA片段,其中片段F1与Magnaporthe oryzae virus 2(MoV2)的Coat Protein(CP)和RNA-dependent RNA polymerase(RdRp)的氨基酸序列均具有99%的同源性,确定为MoV2的基因组;片段F4、F5序列与双分病毒Penicillium stoloniferum virus F(Ps V-F)的RdRp和CP的氨基酸序列分别具有69%和63%的同源性,命名为Magnaporthe oryzae partitivirus virus 2(MoPV2)。MoPV2的基因组含有2条dsRNA:dsRNA 1编码RdRp,dsRNA 2编码CP。根据MoPV2的RdRp编码的氨基酸序列将MoPV2归属于双分病毒科(Partitiviridae)G ammapartitivirus属,是一种新的真菌病毒。通过病毒粒子转染,将MoPV2转到稻瘟菌菌株RB11。与菌株RB11相比,带毒菌株RB11T25的分生孢子产生量显著减少,并且对大麦活体的致病性也有所降低,但其他生物学特征均无明显的影响。本研究在稻瘟菌中发现了一种新的真菌病毒,该病毒能够使稻瘟菌致病力下降,为稻瘟病的防治提供了潜在的病毒资源。

Characterization of a novel partitivirus in the phytopathogenic fungus Magnaporthe oryzae

Rice blast is one of the most devastating diseases around the world. In this study, YC13, a Magnaporthe oryzae strain isolated from a naturally diseased rice leaf, was studied. Many dsRNA fragments were detected in strain YC13 as shown by agarose gel electrophoresis. Nucleic acid sequence of fragment F1 shared 99% identity with coat protein (CP) and RNA-dependent RNA polymerase (RdRp) of Magnaporthe oryzae virus 2 (MoV2). Fragment F4 and F5 showed 69% and 63% similarity with RdRp and CP of Penicillium stoloniferum virus F (PsV-F) respectively, thus designating the newly isolated partitivirus as Magnaporthe oryzae partitivirus virus 2 (MoPV2). MoPV2 genome was composed of two dsRNA fragments. Among them, dsRNA 1 encodes RdRp, dsRNA 2 encodes CP. Phylogenetic analysis of the conserved RdRp region showed that MoPV2 is a new member of Gammapartitivirus. In order to monitor the influence of MoPV2 to its host, strain RB11T25 with only MoPV2 was obtained by transfecting protoplasts of strain RB11 with viral particles derived from strain YC13. Although no significant morphological differences were observed in strain RB11T25, conidial production and virulence to barley was substantially decreased in comparison to the strain RB11. These results suggested a potential resource for biological control of blast disease.