用天然毒素蛋白杀灭害虫是农林病虫害防治的一个重要发展方向。利用家蚕核型多角体病毒(BmNPV)多角体蛋白基因的部分序列与蝎毒素蛋白基因(BmK ITa1)融合表达,SDS-PAGE分析通过融合表达策略构建的含有蝎毒素蛋白基因的重组病毒具有较高的蝎毒素蛋白表达水平,重组病毒vBmBac(polh-)PH5B/35B-BmK ITa1.6His,在家蚕BmN细胞内的BmKITa1蛋白表达水平分别为0.4、0.2 mg/mL。以家蚕和棉铃虫为供试昆虫,探讨融合蝎毒素蛋白的杀虫效果,结果表明:经口添食含融合蝎毒素蛋白的BmN细胞液对不同龄期家蚕幼虫均具有毒性,尤其对低龄幼虫的毒性较强,蚁蚕添食后的死亡率达80%;给1龄期的家蚕和棉铃虫幼虫经口添食含有不同剂量融合蝎毒素蛋白的BmN细胞破碎液,当添食剂量在2.8μg/头时,家蚕的死亡率即达100%,棉铃虫的死亡率达74%。研究结果提示:BmNPV多角体蛋白编码基因的部分序列与蝎毒素蛋白基因融合表达,可提高蝎毒素蛋白的表达水平,且重组病毒表达的蝎毒素蛋白具有较好的杀虫活性,在较低剂量下即可对低龄昆虫产生良好的杀灭效果。
Using natural toxin proteins to perish pests is an important perspective for control of agricultural and forestry pests.In this study,fusion expression of partial sequence from silkworm(Bombyx mori) nucleopolyhedrovirus(BmNPV) polyhedrin gene and toxin protein gene from Buthus martensii Karsch(BmK ITa1) was achieved.SDS-PAGE analysis showed that the recombinant virus constructed from fusion expression strategy had increased expression level of BmK ITa1 protein.Expression level of BmK ITa1 of the recombinant virus vBmBac(polh-) PH5B/35B-BmK ITa1.6His in silkworm BmN cells was 0.4 and 0.2 mg/mL.To assay insecticidal effect of the recombinant protein,silkworm and cotton bollworm(Helicoverpa armigera) were used as the test insect.The results showed that the perorally ingested BmN cell suspension containing fusion BmK ITa1 protein was toxic to all B.mori larvae at different instars,especially to larvae of lower ages.The mortality of newly hatched silkworm larvae was as high as 80%.After BmN cell rupture suspension containing various doses of fusion BmK ITa1 protein was perorally administered to the 1st instar silkworm and cotton bollworm larvae,100% and 74% of silkworm and cotton bollworm larvae died respectively when the administered dose reached 2.8 μg per larva.These results indicated that fusion expression of partial sequence from BmNPV polyhedron encoding gene and toxin protein gene from B.martensii could increase the expression level of B.martensii toxin protein.Nevertheless,B.martensii toxin protein expressed in the recom-binant virus had good insecticidal effect,being able to perish lower age insect larvae at low doses.