Insect resistance to transgenic Bt crops:: Lessons from the laboratory and field
Insect resistance to transgenic Bt crops:: Lessons from the laboratory and field
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DOI：
10.1603/0022-0493-96.4.1031
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发表时间：
2003-08-01
影响因子：
2.2
通讯作者：
Zhao, JZ
中科院分区：
文献类型：
--
作者：
Tabashnik, BE;Carrière, Y;Zhao, JZ
从1996年到2002年，从苏云金芽孢杆菌(Bt)产生杀虫毒素的转基因作物在全世界种植了6200万公顷。尽管预计害虫会迅速对这种Bt作物产生抗性，但在田间暴露于Bt作物导致的抗性频率的增加尚未被记录在案。然而，在实验室和温室试验中，至少有7个三种害虫(小菜蛾[L.]、棉铃虫[Saunders]和棉铃虫Helicoverpa armigera[Hubner])的抗性实验室菌株已经在Bt作物上完成了培育。相比之下，其他几个实验室菌株对饮食中的Bt毒素具有70至10,100倍的抗性，但没有在Bt作物上生存。对高度采用Bt作物的地区的田间种群的监测尚未发现抗性频率的增加。抗性监测的例子包括美国的玉米象(6年)、亚利桑那州的棉铃虫(5年)、中国北部的棉铃虫(3年)和北卡罗来纳州的玉米夜蛾(2年)。推迟对Bt作物抗性的关键因素可能是非Bt寄主植物的避难所，使敏感害虫得以存活，低初始抗性等位基因频率，对Bt作物的抗性隐性遗传，与降低抗性个体相对于非Bt寄主上的敏感个体的适合度的与抗性相关的成本(“适合度成本”)，以及Bt寄主上的抗性品系相对于其在非Bt寄主上的表现所遭受的劣势(“不完全抗性”)。这些因素在害虫-Bt作物系统中的相对重要性各不相同，在某些情况下可能会违反避难策略的关键假设(低抗性等位基因频率和隐性遗传)。Bt作物的成功超出了许多人的预期，但并不排除未来会出现抗性问题。
Transgenic crops that produce insecticidal toxins from the bacterium Bacillus thuringiensis (Bt) grew on >62 million ha worldwide from 1996 to 2002. Despite expectations that pests would rapidly evolve resistance to such Bt crops, increases in the frequency of resistance caused by exposure to Bt crops in the field have not yet been documented. in laboratory and greenhouse tests, however, at least seven resistant laboratory strains of three pests (Plutella xylostella [L.], Pectinophora gossypiella [Saunders], and Helicoverpa armigera [Hubner]) have completed development on Bt crops. In contrast, several other laboratory strains with 70- to 10,100-fold resistance to Bt toxins in diet did not survive on Bt crops. Monitoring of field populations in regions with high adoption of Bt crops has not yet detected increases in resistance frequency. Resistance monitoring examples include Ostrinia nubilalis (Hubner) in the United States (6 yr), P. gossypiella in Arizona (5 yr), H. armigera in northern China (3 yr), and Helicoverpa zea (Boddie) in North Carolina (2 yr). Key factors delaying resistance to Bt crops are probably refuges of non-Bt host plants that enable survival of susceptible pests, low initial resistance allele frequencies, recessive inheritance of resistance to Bt crops, costs associated with resistance that reduce fitness of resistant individuals relative to susceptible individuals on non-Bt hosts ("fitness costs"), and disadvantages suffered by resistant strains on Bt hosts relative to their performance on non-Bt hosts ("incomplete resistance"). The relative importance of these factors varies among pest-Bt crop systems, and violations of key assumptions of the refuge strategy (low resistance allele frequency and recessive inheritance) may occur in some cases. The success of Bt crops exceeds expectations of many, but does not preclude resistance problems in the future.