Downes Sharon, Mahon Rod, Olsen Karen
CSIRO Entomology and Australian Cotton Cooperative Research Centre, Locked Bag 59, Narrabri, NSW 2390, Australia.
J Invertebr Pathol. 2007 Jul;95(3):208-13. doi: 10.1016/j.jip.2007.03.010. Epub 2007 Mar 25.
In the mid-1990 s the Australian Cotton industry adopted an insect-resistant variety of cotton (Ingard) which expresses the Bt toxin Cry1Ac that is specific to a group of insects including the target Helicoverpa armigera. A conservative resistance management plan (RMP), that restricted the area planted to Ingard, was implemented to preserve the efficacy of Cry1Ac until two-gene transgenic cotton was available. In 2004/05 Bollgard II replaced Ingard as the transgenic cotton available in Australia. It improves on Ingard by incorporating an additional insecticidal protein (Cry2Ab). If an appropriate refuge is grown, there is no restriction on the area planted to Bollgard II. In 2004/05 and 2005/06 the Bollgard II acreage represented approximately 80 of the total area planted to cotton in Australia. The sensitivity of field-collected populations of H. armigera to Bt products was assayed before and subsequent to the widespread deployment of Ingard cotton. In 2002 screens against Cry2Ab were developed in preparation for replacement of Ingard with Bollgard II. There have been no reported field failures of Bollgard II due to resistance. However, while alleles that confer resistance to H. armigera in the field are rare for Cry1Ac, they are surprisingly common for Cry2Ab. We present an overview of the current approach adopted in Australia to monitor and adaptively manage resistance to Bt-cotton in field populations of H. armigera and discuss the implications of our findings to date. We also highlight future challenges for resistance management in Australia, many of which extend to other Bt-crop and pest systems.
20世纪90年代中期，澳大利亚棉花产业采用了一种抗虫棉花品种（因加德棉），该品种表达对包括目标害虫棉铃虫在内的一类昆虫具有特异性的Bt毒素Cry1Ac。实施了一项保守的抗性管理计划（RMP），限制因加德棉的种植面积，以保持Cry1Ac的有效性，直到双基因转基因棉花可用。2004/05年度，保铃棉二代取代因加德棉，成为澳大利亚可用的转基因棉花。它通过加入另一种杀虫蛋白（Cry2Ab）对因加德棉进行了改进。如果种植适当的避难作物，保铃棉二代的种植面积没有限制。在2004/05年度和2005/06年度，保铃棉二代的种植面积约占澳大利亚棉花总种植面积的80%。在因加德棉广泛种植之前和之后，对田间采集的棉铃虫种群对Bt产品的敏感性进行了测定。2002年开发了针对Cry2Ab的筛选方法，为用保铃棉二代取代因加德棉做准备。尚未有因抗性导致保铃棉二代田间失效的报道。然而，虽然在田间赋予棉铃虫对Cry1Ac抗性的等位基因很少见，但对Cry2Ab来说却出奇地常见。我们概述了澳大利亚目前采用的监测和适应性管理棉铃虫田间种群对Bt棉花抗性的方法，并讨论了我们迄今研究结果的意义。我们还强调了澳大利亚抗性管理未来面临的挑战，其中许多挑战也适用于其他Bt作物和害虫系统。
