Rabelo Marcelo M, Paula-Moraes Silvana V, Pereira Eliseu Jose G, Siegfried Blair D
Department of Entomology, Universidade Federal de Viçosa, Viçosa 36570-900, MG, Brazil.
Department of Entomology and Nematology, West Florida Research and Education Center, University of Florida, Jay, FL 32565, USA.
Toxins (Basel). 2020 Aug 28;12(9):551. doi: 10.3390/toxins12090551.
Insecticidal toxins from (Bt) are valuable tools for pest management worldwide, contributing to the management of human disease insect vectors and phytophagous insect pests of agriculture and forestry. Here, we report the effects of dual and triple Bt toxins expressed in transgenic cotton cultivars on the fitness and demographic performance of (Boddie)-a noctuid pest, known as cotton bollworm and corn earworm. Life-history traits were determined for individuals of three field populations from a region where overwintering is likely. Triple-gene Bt cotton cultivars that express Cry and Vip3Aa toxins killed 100% of the larvae in all populations tested. In contrast, dual-gene Bt cotton that express Cry1Ac+Cry1F and Cry1Ac+Cry2Ab allowed population growth with the intrinsic rate of population growth () 38% lower than on non-Bt cotton. The insects feeding on Bt cotton plants that express Cry1Ac+Cry2Ab, Cry1Ac+Cry1F, or Cry1Ab+Cry2Ae exhibited reduced larval weight, survival rate, and increased development time. Additionally, fitness parameters varied significantly among the insect populations, even on non-Bt cotton plants, likely because of their different genetic background and/or previous Bt toxin exposure. This is the first report of the comparative fitness of field populations on dual-gene Bt cotton after the recent reports of field resistance to certain Bt toxins. These results document the population growth rates of from an agricultural landscape with 100% Bt cotton cultivars. Our results will contribute to the development and validation of resistance management recommendations.
苏云金芽孢杆菌（Bt）产生的杀虫毒素是全球害虫治理的宝贵工具，有助于防治人类疾病的昆虫传播媒介以及农林领域的植食性害虫。在此，我们报告了转基因棉花品种中表达的双价和三价Bt毒素对棉铃虫（Boddie）——一种夜蛾科害虫，也被称为棉铃虫和玉米穗虫——的适合度和种群统计学表现的影响。对来自一个可能有棉铃虫越冬区域的三个田间种群的个体测定了生活史特征。表达Cry和Vip3Aa毒素的三基因Bt棉花品种在所有测试种群中杀死了100%的幼虫。相比之下，表达Cry1Ac+Cry1F和Cry1Ac+Cry2Ab的双基因Bt棉花使种群能够增长，其种群内禀增长率（r）比在非Bt棉花上低38%。取食表达Cry1Ac+Cry2Ab、Cry1Ac+Cry1F或Cry1Ab+Cry2Ae的Bt棉花植株的昆虫幼虫体重减轻、存活率降低且发育时间延长。此外，即使在非Bt棉花植株上，不同昆虫种群的适合度参数也有显著差异，这可能是由于它们不同的遗传背景和/或之前接触过Bt毒素。这是在近期报道了对某些Bt毒素产生田间抗性之后，关于棉铃虫田间种群在双基因Bt棉花上的相对适合度的首次报告。这些结果记录了种植100% Bt棉花品种的农业景观中棉铃虫的种群增长率。我们的结果将有助于制定和验证抗性治理建议。
