School of Biology and Basic Medical Science, Medical College of Soochow University, Suzhou, Jiangsu 215123, China.
Virus Res. 2011 Jul;159(1):51-6. doi: 10.1016/j.virusres.2011.04.025. Epub 2011 May 6.
SpltNPV-C3 is a novel nucleopolyhedrovirus (NPV) screened from 189 wild Spodoptera litura nucleopolyhedrovirus (SpltNPV) clones collected throughout Japan and has high potential insecticidal activity against S. litura. In this study, we constructed two recombinant SpltNPVs, SpltNPV-Δegt and SpltNPV-Δegt-BmK, which were characterized by the disruption of the UDP-glucosyltransferase gene (egt) only and by replacing the egt locus with the Buthus martensi insect-specific toxin gene (BmK ITa1), respectively. The insecticidal activity of these two recombinant viruses was evaluated by 50% lethal time (LT(50)) and 50% lethal concentration (LC(50)) using third instar S. litura larvae. Bioassays showed that the LT(50) of SpltNPV-Δegt was reduced by 25% at a dose of 10(9) Occlusion bodies (OBs)/ml compared to the wild-type SpltNPV. However, the LC(50) values did not change. The SpltNPV-Δegt-BmK reduced LT(50) by 28% at the highest dose of OBs (10(9) OBs/ml) compared to the wild-type SpltNPV, and the LC(50) was nearly an order of magnitude lower than those of the wild-type SpltNPV and SpltNPV-Δegt. However, there was no discernable difference in the LT(50) between SpltNPV-Δegt-BmK and SpltNPV-Δegt when the 3rd instars of S. litura were fed a dose of 10(8) or 10(9) OBs/ml. The results suggest that these two recombinant forms of SpltNPV provide further opportunities to develop these viruses into commercially viable products to control S. litura populations.
SpltNPV-C3 是一种新型的核型多角体病毒（NPV），从日本各地收集的 189 个野生斜纹夜蛾核型多角体病毒（SpltNPV）克隆中筛选出来，对斜纹夜蛾具有很高的潜在杀虫活性。在本研究中，我们构建了两种重组 SpltNPV，SpltNPV-Δegt 和 SpltNPV-Δegt-BmK，它们分别通过破坏 UDP-葡萄糖基转移酶基因（egt）和用 Buthus martensi 昆虫特异性毒素基因（BmK ITa1）取代 egt 基因来进行特征化。通过使用三龄斜纹夜蛾幼虫评估这两种重组病毒的 50%致死时间（LT(50)）和 50%致死浓度（LC(50)）来评价它们的杀虫活性。生物测定表明，与野生型 SpltNPV 相比，剂量为 10(9)个包埋体（OBs）/ml 时，SpltNPV-Δegt 的 LT(50)降低了 25%。然而，LC(50)值没有变化。SpltNPV-Δegt-BmK 在最高 OBs 剂量（10(9)OBs/ml）下，与野生型 SpltNPV 相比，LT(50)降低了 28%，LC(50)比野生型 SpltNPV 和 SpltNPV-Δegt 低近一个数量级。然而，当三龄斜纹夜蛾幼虫喂食 10(8)或 10(9)OBs/ml 剂量时，SpltNPV-Δegt-BmK 和 SpltNPV-Δegt 之间的 LT(50)没有明显差异。结果表明，这两种重组形式的 SpltNPV 为进一步开发这些病毒成为商业可行的产品来控制斜纹夜蛾种群提供了机会。
