Department of Entomology, Louisiana State University Agricultural Center, Baton Rouge, LA, USA.
Department of Entomology, Texas A&M University, College Station, TX, USA.
Pest Manag Sci. 2017 Dec;73(12):2495-2503. doi: 10.1002/ps.4644. Epub 2017 Aug 24.
Gene-pyramiding by combining two or more dissimilar Bacillus thuringiensis (Bt) proteins into a crop has been used to delay insect resistance. The durability of gene-pyramiding can be reduced by cross-resistance. Fall armyworm, Spodoptera frugiperda, is a major target pest of the Cry2Ab2 protein used in pyramided Bt corn and cotton. Here, we provide the first experimental evaluation of cross-resistance in S. frugiperda selected with Cry2Ab2 corn to multiple Bt sources including purified Bt proteins, Bt corn and Bt cotton.
Concentration - response bioassays showed that resistance ratios for Cry2Ab2-resistant (RR) relative to Cry2Ab2-susceptible (SS) S. frugiperda were -1.4 for Cry1F, 1.2 for Cry1A.105, >26.7 for Cry2Ab2, >10.0 for Cry2Ae and -1.1 for Vip3A. Larvae of Cry2Ab2-heterozygous (RS), SS and RR S. frugiperda were all susceptible to Bt corn and Bt cotton containing Cry1 (Cry1F or Cry1A.105) and/or Vip3A proteins. Pyramided Bt cotton containing Cry1Ac + Cry2Ab2 or Cry1Ab + Cry2Ae were also effective against SS and RS, but not RR.
These findings suggest that Cry2Ab2-corn-selected S. frugiperda is not cross-resistant to Cry1F, Cry1A.105 or Vip3A protein, or corn and cotton plants containing these Bt proteins, but it can cause strong cross-resistance to Cry2Ae and Bt crops expressing similar Bt proteins. © 2017 Society of Chemical Industry.
通过将两种或多种不同的苏云金芽孢杆菌（Bt）蛋白组合到作物中进行基因叠加已被用于延缓昆虫抗性。基因叠加的持久性可能会因交互抗性而降低。草地贪夜蛾，Spodoptera frugiperda，是使用叠加 Bt 玉米和棉花的 Cry2Ab2 蛋白的主要靶标害虫。在这里，我们首次对使用 Cry2Ab2 玉米选择的 S. frugiperda 进行了交叉抗性的实验评估，包括纯化的 Bt 蛋白、Bt 玉米和 Bt 棉花等多种 Bt 来源。
浓度-反应生物测定显示，Cry2Ab2 抗性（RR）相对于 Cry2Ab2 敏感（SS）S. frugiperda 的抗性比为 Cry1F 的-1.4，Cry1A.105 的 1.2，Cry2Ab2 的>26.7，Cry2Ae 的>10.0，Vip3A 的-1.1。Cry2Ab2 杂合（RS）、SS 和 RR S. frugiperda 的幼虫均对含有 Cry1（Cry1F 或 Cry1A.105）和/或 Vip3A 蛋白的 Bt 玉米和 Bt 棉花敏感。含有 Cry1Ac+Cry2Ab2 或 Cry1Ab+Cry2Ae 的叠加 Bt 棉花对 SS 和 RS 有效，但对 RR 无效。
这些发现表明，Cry2Ab2 玉米选择的 S. frugiperda 对 Cry1F、Cry1A.105 或 Vip3A 蛋白或含有这些 Bt 蛋白的玉米和棉花植物没有交叉抗性，但它可以对表达类似 Bt 蛋白的 Cry2Ae 和 Bt 作物引起强烈的交叉抗性。© 2017 化学工业协会。
