Unité de Recherche IRD 072, CNRS UPR9034, Laboratoire Evolution, Génome et Spéciation, Gif-sur-yvette, France.
PLoS One. 2013 Jul 2;8(7):e69675. doi: 10.1371/journal.pone.0069675. Print 2013.
Transgenic crops expressing Bacillus thuringiensis (Bt) toxins have been adopted worldwide, notably in developing countries. In spite of their success in controlling target pests while allowing a substantial reduction of insecticide use, the sustainable control of these pest populations is threatened by the evolution of resistance. The implementation of the "high dose/refuge" strategy for managing insect resistance in transgenic crops aims at delaying the evolution of resistance to Bt crops in pest populations by promoting survival of susceptible insects. However, a crucial condition for the "high dose/refuge" strategy to be efficient is that the inheritance of resistance should be functionally recessive. Busseolafusca developed high levels of resistance to the Bt toxin Cry 1Ab expressed in Bt corn in South Africa. To test whether the inheritance of B. fusca resistance to the Bt toxin could be considered recessive we performed controlled crosses with this pest and evaluated its survival on Bt and non-Bt corn. Results show that resistance of B. fusca to Bt corn is dominant, which refutes the hypothesis of recessive inheritance. Survival on Bt corn was not lower than on non-Bt corn for both resistant larvae and the F1 progeny from resistant × susceptible parents. Hence, resistance management strategies of B. fusca to Bt corn must address non-recessive resistance.
转 Bt 毒素基因作物已在全球范围内得到广泛应用，尤其是在发展中国家。尽管这些作物在控制靶标害虫的同时大量减少了杀虫剂的使用，但这些害虫种群对杀虫剂的抗性进化仍对可持续控制构成威胁。实施“高剂量/避难所”策略来管理转基因作物中的昆虫抗性，旨在通过促进敏感昆虫的生存来延缓害虫种群对 Bt 作物的抗性进化。然而，“高剂量/避难所”策略要有效的一个关键条件是，抗性的遗传应该是隐性的。南非的黄曲条跳甲已对表达在 Bt 玉米中的 Bt 毒素 Cry1Ab 产生了高水平的抗性。为了测试黄曲条跳甲对 Bt 毒素的抗性遗传是否可以被认为是隐性的，我们用这种害虫进行了控制杂交，并评估了它在 Bt 和非 Bt 玉米上的生存能力。结果表明，黄曲条跳甲对 Bt 玉米的抗性是显性的，这推翻了隐性遗传的假设。对于抗性幼虫和来自抗性×敏感亲代的 F1 后代，在 Bt 玉米上的存活率并不低于在非 Bt 玉米上的存活率。因此，必须针对黄曲条跳甲对 Bt 玉米的非隐性抗性来制定抗性管理策略。
