USDA Agricultural Research Service, Center for Grain and Animal Health Research, Manhattan, KS 66502, USA.
Pest Manag Sci. 2011 May;67(5):568-73. doi: 10.1002/ps.2099. Epub 2011 Jan 26.
Environmental impacts and resistance to insecticides pose serious challenges to stored-product insect and other types of pest control. Insect-resistant transgenic grain is a potential alternative to fumigants, but candidate control proteins are needed, especially for coleopterans. Therefore, we evaluated the efficacy of a coleopteran-active toxin, Bacillus thuringiensis Cry3Aa, with or without protease inhibitors, in laboratory feeding assays against coleopteran storage pests.
In a comparison of the toxicity of Cry3Aa protoxin towards three species of coleopteran storage pests, Tenebrio molitor L. was found to be most sensitive, Tribolium castaneum (Herbst.) was most refractory and Rhyzopertha dominica F. displayed an intermediate response. For R. dominica, Cry3Aa combined with 3500 mg potato carboxypeptidase inhibitor or 5000 mg aprotinin kg(-1) diet resulted in both delayed development and increased mortality. Potato carboxypeptidase inhibitor and bovine aprotinin reduced the LC(50) of Cry3Aa for R. dominica two- and threefold respectively. Cry3Aa treatment resulted in fewer progeny from R. dominica, and progeny was further reduced when the protoxin was combined with potato carboxypeptidase inhibitor.
These data support the hypothesis that a combination of Cry3Aa protoxin and protease inhibitors, particularly a potato carboxypeptidase inhibitor, may have applications in control strategies for preventing damage to stored products and grains by coleopteran pests.
环境影响和杀虫剂抗性对仓储物害虫和其他类型的害虫防治构成了严重挑战。抗虫转基因谷物是熏蒸剂的潜在替代品，但需要候选控制蛋白，尤其是针对鞘翅目昆虫。因此，我们评估了苏云金芽孢杆菌 Cry3Aa 这种对鞘翅目昆虫具有活性的毒素，以及添加或不添加蛋白酶抑制剂，在实验室饲养试验中对鞘翅目仓储害虫的防治效果。
在 Cry3Aa 原毒素对三种鞘翅目仓储害虫的毒性比较中，发现黄粉虫最敏感，赤拟谷盗最具抗性，玉米象则表现出中等反应。对于玉米象，Cry3Aa 与 3500mg 马铃薯羧肽酶抑制剂或 5000mg 抑肽酶 kg(-1) 饲料结合使用，可导致发育延迟和死亡率增加。马铃薯羧肽酶抑制剂和牛源抑肽酶分别将 Cry3Aa 对玉米象的 LC(50)降低了两倍和三倍。Cry3Aa 处理导致玉米象的后代数量减少，而原毒素与马铃薯羧肽酶抑制剂结合使用时，后代数量进一步减少。
这些数据支持这样一种假设，即 Cry3Aa 原毒素与蛋白酶抑制剂的组合，特别是马铃薯羧肽酶抑制剂，可能在防治鞘翅目害虫对储存产品和谷物造成损害的控制策略中具有应用潜力。
