斜纹夜蛾和甜菜夜蛾核型多角体病毒异源重组后的变异

Host range changes generated by heterogeneous recombination of two nucleopolyhedroviruses isolated from Spodoptera litura and Spodoptera exigua

为了明确不同宿主域核型多角体病毒(NPV)间的重组特性,揭示病毒进化规律以及发掘宿主域扩大病毒,本试验将2种病毒[不能经口感染甜菜夜蛾的斜纹夜蛾核型多角体病毒日本福冈株(SlNPV)、不能经口感染斜纹夜蛾的甜菜夜蛾核型多角体病毒美国株(SeNPV)]共同侵染宿主活体,通过饲料添毒法测定病毒异源重组前后的活性,并进一步通过透射电镜观察病毒多角体超微结构,利用限制性酶切比较病毒基因组遗传差异。结果发现,SlNPV和SeNPV在共同经口侵染甜菜夜蛾后,产生能成功侵染甜菜夜蛾和斜纹夜蛾的宿主域扩大重组病毒(Sl-NPV-1)株系,其对斜纹夜蛾的致死中浓度(LC50)与SlNPV间无显著差异,同时SlNPV-1对甜菜夜蛾的侵染力显著低于SeNPV。SlNPV-1株系的超微结构与SlNPV无显著差异。另外,SlNPV-1基因组DNA限制性酶切图谱与SlN-PV的图谱相同。表明,SlNPV和SeNPV混合侵染活体宿主后,能产生对斜纹夜蛾和甜菜夜蛾都具有侵染活性的宿主域扩大重组病毒。

To study the recombination characteristics between nucleopolyhedroviruses（NPVs）,and reveal the rules of evolution in NPVs and explore new NPVs with expanded host range,two NPVs[Spodoptera litura NPV（SlNPV） and S.exigua NPV（SeNPV）] were used to co-infect alive host in vivo.The biological activities of NPVs before and after co-infection were determined,and the ultrastructure of polyhedra were observed under transmission electron microscope.The results showed that,oral co-infection of SlNPV and SeNPV resulted in a new strain of NPV（SlNPV-1） which could infect both S.litura and S.exigua.The lethal concentration of 50 percent individuals（LC50） of SlNPV-1 against S.litura was not significantly different from that of SlNPV.The biological activity of SlNPV-1 against S.exigua,was significantly lower than that of SeNPV.The ultrastructure of polyhedra in SlNPV-1 was not significantly different from that of SlNPV.Restriction enzyme profiles of genomic DNA from SlNPV-1 was the same as that of SlNPV.All these results indicated that co-infection of SlNPV and SeNPV in vivo could generate a new strain of NPV with an expanded host range againt both S.litura and S.exigua.