Agricultural Biotechnology Division, National Institute for Biotechnology & Genetic Engineering (NIBGE), Faisalabad, Pakistan.
Pakistan Institute for Engineering and Applied Sciences (PIEAS), Nilore Islamabad, Pakistan.
J Econ Entomol. 2020 Dec 9;113(6):2959-2971. doi: 10.1093/jee/toaa211.
Agricultural pest infestation is as old as domestication of food crops and contributes a major share to the cost of crop production. In a transgenic pest control approach, plant production of Vip3A, an insecticidal protein from Bacillus thuringiensis, is effective against lepidopteran pests. A synthetic Vip3A gene was evaluated for efficacy against Spodoptera litura Fabricius (Lepidoptera: Noctuidae; cotton leafworm), Spodoptera exigua Hübner (Lepidoptera: Noctuidae; beet armyworm), Spodoptera frugiperda Smith (Lepidoptera: Noctuidae; fall armyworm), Helicoverpa armigera Hübner (Lepidoptera: Noctuidae; cotton bollworm), Helicoverpa zea Boddie (Lepidoptera: Noctuidae; corn earworm), Heliothis virescens Fabricius (Lepidoptera: Noctuidae; tobacco budworm), and Manduca sexta L. (Lepidoptera: Sphingidae; tobacco hornworm) in tobacco. In artificial diet assays, the concentration required to achieve 50% mortality was highest for H. zea followed by H. virescens > S. exigua > H. armigera > M. sexta > S. frugiperda > S. litura. By contrast, in bioassays with detached leaves from Vip3A transgenic tobacco, the time until 50% lethality was M. sexta > H. virescens > S. litura > H. zea > H. armigera > S. exigua. There was no significant correlation between the artificial diet and transgenic plant bioassay results. Notably, the two insect species that are best-adapted for growth on tobacco, M. sexta and H. virescens, showed the greatest time to 50% mortality on Vip3A-transgenic tobacco. Together, our results suggest that artificial diet assays may be a poor predictor of Vip3A efficacy in transgenic plants, lepidopteran species vary in their sensitivity to Vip3A in diet-dependent manner, and host plant adaptation of the targeted herbivores should be considered when designing transgenic plants for pest control.
农业害虫的侵害与粮食作物的驯化一样古老，对作物生产成本造成了重大影响。在一种转基因害虫防治方法中，植物生产的 Vip3A 是一种来自苏云金芽孢杆菌的杀虫蛋白，对鳞翅目害虫有效。合成的 Vip3A 基因被评估对斜纹夜蛾 Fabricius（鳞翅目：夜蛾科；棉叶虫）、甜菜夜蛾 Hübner（鳞翅目：夜蛾科；粘虫）、草地贪夜蛾 Smith（鳞翅目：夜蛾科；秋粘虫）、棉铃虫 Hübner（鳞翅目：夜蛾科；棉铃虫）、玉米穗虫 Boddie（鳞翅目：夜蛾科；玉米穗虫）、烟夜蛾 Fabricius（鳞翅目：夜蛾科；烟草夜蛾）和烟卷夜蛾 L.（鳞翅目： Sphingidae；烟草卷叶蛾）具有防治效果。在人工饲料测定中，达到 50%死亡率所需的浓度以 H.zea 最高，其次是 H.virescens>S.exigua>H.armigera>M.sexta>S.frugiperda>S.litura。相比之下，在 Vip3A 转基因烟草离体叶片的生物测定中，50%致死时间是 M.sexta>H.virescens>S.litura>H.zea>H.armigera>S.exigua。人工饲料与转基因植物生物测定结果之间没有显著相关性。值得注意的是，两种最适应在烟草上生长的昆虫物种，烟卷夜蛾和烟夜蛾，在 Vip3A 转基因烟草上表现出最大的 50%死亡率时间。总之，我们的结果表明，人工饲料测定可能是预测 Vip3A 在转基因植物中的功效的一个较差指标，鳞翅目昆虫在依赖于饮食的方式上对 Vip3A 的敏感性不同，在设计用于害虫防治的转基因植物时，应考虑目标食草动物对寄主植物的适应性。
