Increased survival of western corn rootworm on transgenic corn within three generations of on-plant greenhouse selection
Increased survival of western corn rootworm on transgenic corn within three generations of on-plant greenhouse selection
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DOI：
10.1073/pnas.0805565105
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发表时间：
2008-12-09
影响因子：
11.1
通讯作者：
Hibbard, Bruce E.
中科院分区：
文献类型：
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作者：
Meihls, Lisa N.;Higdon, Matthew L.;Hibbard, Bruce E.
为了延缓昆虫对产生苏云金芽孢杆菌(Bt)毒素的转基因作物的抗性进化，许多地区需要不产生Bt毒素的寄主植物在附近的“避难所”。当Bt作物中的毒素浓度高到足以杀死所有或几乎所有杂合的抗药性昆虫时，这种避难所有望最有效地减缓抗药性。然而，最近引入的Bt玉米不符合控制西部玉米根虫(Diabrotica Virgifera)的“高剂量”标准。采用温室方法在表达Cry3Bb1蛋白的转基因玉米上饲养WCR，其中约25%的先前未暴露的幼虫相对于等值线存活(与田间的1-4%相比)。在温室试验中，在Bt玉米上饲养3代WCR幼虫后，WCR幼虫在Bt玉米和等位基因玉米上的存活率相当，而在人工饲料上用Cry3Bb1蛋白进行饲料生物测定时，持续暴露群体的LC_(50)是对照群体的22倍。经过6个世代的温室选择，Bt玉米上的幼虫回收率与田间等位基因玉米的比率是对照群体的11.7倍。取舍6代并不会降低温室转Bt基因玉米的存活率。结果表明，在没有与未暴露的甲虫交配的情况下，对选择的快速反应是可能的，强调了有效的避难所对抗性管理的重要性。
To delay evolution of insect resistance to transgenic crops producing Bacillus thuringiensis (Bt) toxins, nearby "refuges'' of host plants not producing Bt toxins are required in many regions. Such refuges are expected to be most effective in slowing resistance when the toxin concentration in Bt crops is high enough to kill all or nearly all insects heterozygous for resistance. However, Bt corn, Zea mays, introduced recently does not meet this "high-dose'' criterion for control of western corn rootworm (WCR), Diabrotica virgifera virgifera. A greenhouse method of rearing WCR on transgenic corn expressing the Cry3Bb1 protein was used in which approximately 25% of previously unexposed larvae survived relative to isoline survival (compared to 1-4% in the field). After three generations of full larval rearing on Bt corn (Constant-exposure colony), WCR larval survival was equivalent on Bt corn and isoline corn in greenhouse trials, and the LC50 was 22-fold greater for the Constant-exposure colony than for the Control colony in diet bioassays with Cry3Bb1 protein on artificial diet. After six generations of greenhouse selection, the ratio of larval recovery on Bt corn to isoline corn in the field was 11.7-fold greater for the Constant-exposure colony than the Control colony. Removal from selection for six generations did not decrease survival on Bt corn in the greenhouse. The results suggest that rapid response to selection is possible in the absence of mating with unexposed beetles, emphasizing the importance of effective refuges for resistance management.