V-ATPase H表达量下调增强棉铃虫对Cry1Ac的抗性

棉铃虫Helicoverpa armigera是世界性重要农业害虫。目前防治棉铃虫的主要手段是种植转苏云金芽胞杆菌Bacillus thuringiensis(Bt)杀虫蛋白的转基因作物。本文旨在研究棉铃虫V-ATPase H在Cry1Ac蛋白毒力和抗性中的作用。利用实时荧光定量qRT-PCR技术分析V-ATPase H在Cry1Ac抗、感品系棉铃虫幼虫中肠及敏感品系棉铃虫幼虫受Cry1Ac诱导后的表达情况；在昆虫Sf9细胞中过表达V-ATPase H对其进行细胞定位，通过细胞毒力试验验证其对Cry1Ac毒力的影响。结果发现棉铃虫V-ATPase H基因在抗性品系中低表达，并且V-ATPase H在受到Cry1Ac诱导时也低表达；在Sf9细胞内表达V-ATPase H蛋白发现其在整个细胞中都有分布，过表达该蛋白后增强了细胞对Cry1Ac蛋白的敏感性。结果表明V-ATPase H参与Cry1Ac蛋白的毒力。

Down-regulation of V-ATPase subunit H expression increased resistance to Cry1Ac of Helicoverpa armigera (Lepidoptera: Noctuidae)

The cotton bollworm Helicoverpa armigera, which affects many crops such as cotton, is an important agricultural pest worldwide. At present, the main method to control cotton bollworm is to plant the transgenic crops that express Bacillus thuringiensis (Bt) insecticidal proteins. This study aims to explore the role of vacuolar-type proton ATPase subunit H (V-ATPase H) in the toxicity of Cry1Ac and insect resistance to Cry1Ac. Real-time quantitative PCR (qRT-PCR) was used to investigate the expression levels of V-ATPase H in the midgut of Cry1Ac-susceptible and resistant cotton bollworm larvae and in the midgut of Cry1Ac-susceptible larvae that were induced by Cry1Ac. V-ATPase H was overexpressed in Sf9 cells for cellular localization, and its effect on Cry1Ac toxicology was verified by cytotoxicity assay. The results showed that the expression level of V-ATPase H was lower in Cry1Ac-resistant than that in Cry1Ac-susceptible strain. In addition, its expression level was lower in Cry1Ac-induced larvae. The intracellular expression of V-ATPase H showed that it was distributed in the whole cell, and the over-expression of V-ATPase H enhanced the sensitivity of cells to Cry1Ac proteins. The above results indicated that V-ATP H may be involved in the toxicity of Cry1Ac.