Department of Entomology, Texas A&M University, College Station, TX, USA.
Bayer Crop Science, St. Louis, MO, USA.
Pest Manag Sci. 2023 Dec;79(12):5173-5179. doi: 10.1002/ps.7720. Epub 2023 Aug 28.
Pyramiding Bt proteins is a key strategy to delay insect resistance development. However, the durability of pyramided Bt crops for controlling insect pests is threatened by cross-resistance among Bt proteins, which can ultimately contribute to resistance development. The corn earworm, Helicoverpa zea, is a major agricultural pest of pyramided Bt crops. Previous studies have examined cross-resistance and redundant killing of Cry resistance in H. zea, but such information is lacking for Vip3Aa resistance in this pest. Here, we evaluated cross-resistance and redundant killing of Vip3Aa-resistant H. zea to purified Bt proteins, as well as Bt corn and Bt cotton.
Diet bioassays demonstrated high susceptibility of Vip3Aa-resistant H. zea to Cry1Ac, Cry1A.105, and Cry2Ab2 purified proteins. No Vip3Aa-susceptible, -heterozygous, or -resistant H. zea could survive on pyramided Bt corn containing Cry1 and/or Cry2 proteins. Complete redundant killing was observed in pyramided Bt corn containing Cry1 and/or Cry2 proteins against Vip3Aa resistance in H. zea. Vip3Aa-susceptible, -heterozygous, and -resistant H. zea exhibited survival rates ranging from 0.0% to 22.5% on pyramided Bt cotton with Cry1 and/or Cry2 proteins. Incomplete to complete redundant killing was observed for Vip3Aa-resistant H. zea on pyramided Bt cotton containing Cry1 and/or Cry2 proteins.
Our findings indicate that Vip3Aa-resistant H. zea does not exhibit positive cross-resistance to Cry1 or Cry2 proteins. In addition, most pyramided Bt crops showed complete or nearly complete redundant killing of Vip3Aa-resistant H. zea. These results indicate that a pyramiding strategy would often be effective for managing Vip3Aa resistance in regions of the United States where H. zea has not evolved resistance to Cry1 and Cry2 toxins. © 2023 Society of Chemical Industry.
堆叠 Bt 蛋白是延缓昆虫抗药性发展的关键策略。 然而，Bt 蛋白之间的交叉抗性会威胁到堆叠 Bt 作物对害虫的持久性控制，这最终可能导致抗药性的发展。 玉米穗虫（Helicoverpa zea）是堆叠 Bt 作物的主要农业害虫。 以前的研究已经研究了 Cry 抗性在 H. zea 中的交叉抗性和冗余致死，但在这种害虫中缺乏 Vip3Aa 抗性的相关信息。 在这里，我们评估了 Vip3Aa 抗性的 H. zea 对纯化的 Bt 蛋白以及 Bt 玉米和 Bt 棉花的交叉抗性和冗余致死。
饮食生物测定表明，Vip3Aa 抗性的 H. zea 对纯化的 Cry1Ac、Cry1A.105 和 Cry2Ab2 蛋白高度敏感。 没有 Vip3Aa 敏感、杂合或抗性的 H. zea 能够在含有 Cry1 和/或 Cry2 蛋白的堆叠 Bt 玉米上存活。 在含有 Cry1 和/或 Cry2 蛋白的堆叠 Bt 玉米中，观察到对 H. zea 中的 Vip3Aa 抗性的完全冗余致死。 Vip3Aa 敏感、杂合和抗性的 H. zea 在含有 Cry1 和/或 Cry2 蛋白的堆叠 Bt 棉花上的存活率范围为 0.0%至 22.5%。 在含有 Cry1 和/或 Cry2 蛋白的堆叠 Bt 棉花中，对 Vip3Aa 抗性的 H. zea 表现出不完全到完全的冗余致死。
我们的研究结果表明，Vip3Aa 抗性的 H. zea 对 Cry1 或 Cry2 蛋白没有表现出正向交叉抗性。 此外，大多数堆叠 Bt 作物对 Vip3Aa 抗性的 H. zea 表现出完全或几乎完全的冗余致死。 这些结果表明，在尚未对 Cry1 和 Cry2 毒素产生抗性的美国地区，堆叠策略通常是管理 Vip3Aa 抗性的有效方法。 © 2023 化学工业协会。
