Tabashnik Bruce E, Fabrick Jeffrey A, Henderson Scottie, Biggs Robert W, Yafuso Christine M, Nyboer Megan E, Manhardt Nancy M, Coughlin Laura A, Sollome James, Carrière Yves, Dennehy Timothy J, Morin Shai
Department of Entomology, University of Arizona, Tucson, AZ 85721, USA.
J Econ Entomol. 2006 Oct;99(5):1525-30. doi: 10.1603/0022-0493-99.5.1525.
Transgenic crops producing toxins from the bacterium Bacillus thuringiensis (Bt) kill insect pests and can reduce reliance on insecticide sprays. Although Bt cotton (Gossypium hirsutum L.) and Bt corn (Zea mays L.) covered 26 million ha worldwide in 2005, their success could be cut short by evolution of pest resistance. Monitoring the early phases of pest resistance to Bt crops is crucial, but it has been extremely difficult because bioassays usually cannot detect heterozygotes harboring one allele for resistance. We report here monitoring of resistance to Bt cotton with DNA-based screening, which detects single resistance alleles in heterozygotes. We used polymerase chain reaction primers that specifically amplify three mutant alleles of a cadherin gene linked with resistance to Bt cotton in pink bollworm, Pectinophora gossypiella (Saunders), a major pest. We screened DNA of 5,571 insects derived from 59 cotton fields in Arizona, California, and Texas during 2001-2005. No resistance alleles were detected despite a decade of exposure to Bt cotton. In conjunction with data from bioassays and field efficacy tests, the results reported here contradict predictions of rapid pest resistance to Bt crops.
产生苏云金芽孢杆菌（Bt）毒素的转基因作物能够杀死害虫，并可减少对杀虫剂喷洒的依赖。尽管2005年全球范围内转基因抗虫棉（陆地棉）和转基因抗虫玉米（玉米）的种植面积达2600万公顷，但其成功可能会因害虫抗性的进化而夭折。监测害虫对Bt作物抗性的早期阶段至关重要，但这极具难度，因为生物测定通常无法检测到携带一个抗性等位基因的杂合子。我们在此报告了利用基于DNA的筛选方法监测对Bt棉花的抗性，该方法可检测杂合子中的单个抗性等位基因。我们使用了聚合酶链反应引物，该引物能特异性扩增与棉铃虫（棉红铃虫，一种主要害虫）对Bt棉花抗性相关的钙黏蛋白基因的三个突变等位基因。我们在2001年至2005年期间对来自亚利桑那州、加利福尼亚州和得克萨斯州59个棉田的5571只昆虫的DNA进行了筛选。尽管棉铃虫接触Bt棉花已有十年，但未检测到抗性等位基因。结合生物测定和田间药效试验的数据，本文报告的结果与害虫对Bt作物快速产生抗性的预测相矛盾。
