Kain Wendy, Song Xiaozhao, Janmaat Alida F, Zhao Jian-Zhou, Myers Judith, Shelton Anthony M, Wang Ping
Department of Entomology, Cornell University, New York State Agricultural Experiment Station, Geneva, New York, USA.
Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada.
Appl Environ Microbiol. 2015 Mar;81(5):1884-90. doi: 10.1128/AEM.03382-14. Epub 2014 Dec 5.
Two populations of Trichoplusia ni that had developed resistance to Bacillus thuringiensis sprays (Bt sprays) in commercial greenhouse vegetable production were tested for resistance to Bt cotton (BollGard II) plants expressing pyramided Cry1Ac and Cry2Ab. The T. ni colonies resistant to Bacillus thuringiensis serovar kurstaki formulations were not only resistant to the Bt toxin Cry1Ac, as previously reported, but also had a high frequency of Cry2Ab-resistant alleles, exhibiting ca. 20% survival on BollGard II foliage. BollGard II-resistant T. ni strains were established by selection with BollGard II foliage to further remove Cry2Ab-sensitive alleles in the T. ni populations. The BollGard II-resistant strains showed incomplete resistance to BollGard II, with adjusted survival values of 0.50 to 0.78 after 7 days. The resistance to the dual-toxin cotton plants was conferred by two genetically independent resistance mechanisms: one to Cry1Ac and one to Cry2Ab. The 50% lethal concentration of Cry2Ab for the resistant strain was at least 1,467-fold that for the susceptible T. ni strain. The resistance to Cry2Ab in resistant T. ni was an autosomally inherited, incompletely recessive monogenic trait. Results from this study indicate that insect populations under selection by Bt sprays in agriculture can be resistant to multiple Bt toxins and may potentially confer resistance to multitoxin Bt crops.
在商业温室蔬菜生产中对苏云金芽孢杆菌喷雾剂（Bt喷雾剂）产生抗性的两个粉纹夜蛾种群，被测试对表达复合Cry1Ac和Cry2Ab的Bt棉花（抗虫棉II）植株的抗性。对苏云金芽孢杆菌库尔斯塔克亚种制剂产生抗性的粉纹夜蛾群体，不仅如先前报道的那样对Bt毒素Cry1Ac具有抗性，而且还具有高频率的Cry2Ab抗性等位基因，在抗虫棉II叶片上的存活率约为20%。通过用抗虫棉II叶片进行筛选，建立了抗抗虫棉II的粉纹夜蛾品系，以进一步去除粉纹夜蛾群体中对Cry2Ab敏感的等位基因。抗抗虫棉II的品系对抗虫棉II表现出不完全抗性，7天后的校正存活率为0.50至0.78。对双毒素棉花植株的抗性由两种遗传上独立的抗性机制赋予：一种针对Cry1Ac，另一种针对Cry2Ab。抗性品系对Cry2Ab的50%致死浓度至少是敏感粉纹夜蛾品系的1467倍。抗性粉纹夜蛾对Cry2Ab的抗性是一种常染色体遗传的、不完全隐性的单基因性状。本研究结果表明，农业中受Bt喷雾剂选择的昆虫种群可能对多种Bt毒素具有抗性，并可能对多毒素Bt作物产生抗性。
