State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, No. 2, West Yuanmingyuan Road, Beijing 100193, China.
ERI de Biotecnología y Biomedicina (BIOTECMED), Department of Genetics, Universitat de València, 46100 Burjassot, Spain.
Toxins (Basel). 2018 Nov 4;10(11):454. doi: 10.3390/toxins10110454.
The oriental armyworm (OAW), (Walker), is a destructive pest of agricultural crops in Asia and Australia. Commercialized Bt crops have performed very well against their target pests; however, very few studies have been done on the susceptibility of OAW to Bt toxins in either sprays or expressed in Bt crops. In this work, we evaluated the toxicities of Cry1Ab, Cry1Ac, Cry1Ah, Cry1Fa, Cry2Aa, Cry2Ab, Cry1Ie, Vip3Aa19, Vip3Aa16, and Vip3Ca against OAW neonate larvae, as well as the interaction between Cry and Vip toxins. The results from bioassays revealed that LC (lethal concentration for 50% mortality) values ranged from 1.6 to 78.6 μg/g (toxin/diet) for those toxins. Among them, Vip3 proteins, along with Cry1A proteins and Cry2Aa, were the ones with the highest potency, with LC values ranging from 1.6 to 7.4 μg/g. Synergism between Cry and Vip toxins was observed, being high in the combination of Vip3Aa16 with Cry1 toxins, with synergetic factors ranging from 2.2 to 9.2. The Vip3Ca toxin did not show any synergistic effect with any of the toxins tested. These results can help in designing new combinations of pyramiding genes in Bt crops, as well as in recombinant bacteria, for the control of OAW as well as for resistance management programs.
东方粘虫（OAW），（Walker），是亚洲和澳大利亚农业作物的破坏性害虫。商业化的 Bt 作物对其靶标害虫表现非常出色；然而，很少有研究涉及 OAW 对 Bt 毒素在喷雾或在 Bt 作物中表达的敏感性。在这项工作中，我们评估了 Cry1Ab、Cry1Ac、Cry1Ah、Cry1Fa、Cry2Aa、Cry2Ab、Cry1Ie、Vip3Aa19、Vip3Aa16 和 Vip3Ca 对 OAW 幼虫的毒性，以及 Cry 和 Vip 毒素之间的相互作用。生物测定结果表明，这些毒素对 OAW 幼虫的致死浓度（LC50）值范围为 1.6 至 78.6μg/g（毒素/饲料）。其中，Vip3 蛋白与 Cry1A 蛋白和 Cry2Aa 一起具有最高的效力，LC 值范围为 1.6 至 7.4μg/g。Cry 和 Vip 毒素之间存在协同作用，Vip3Aa16 与 Cry1 毒素的组合协同作用最高，协同因子范围为 2.2 至 9.2。Vip3Ca 毒素与测试的任何毒素均未显示出协同作用。这些结果有助于设计 Bt 作物和重组细菌中基因叠加的新组合，以控制 OAW 以及抗性管理计划。
