害虫对转基因Bt作物的抗性及其管理对策

PESTS RESISTANCE TO TRANSGENIC BT CROPS AND THEIR MANAGEMENT STRATEGIES

至今为止，已经有２６种植物成功地转入了Ｂｔ毒蛋白基因，它们将在防治害虫中发挥重要作用．Ｂｔ作物释放的潜在风险是害虫的抗性进化．害虫对Ｂｔ毒蛋白产生抗性的机制包括行为躲避、生理生化机制及遗传机制．抗性等位基因的初始频率和抗性的遗传稳定性等特性影响着抗性管理对策的实施和效用．抗性管理对策包括Ｂｔ作物的轮作、转入多个杀虫基因、Ｂｔ毒蛋白高剂量表达、低剂量表达和目标特异表达以及避难所策略等，它们是互为补充的．其中，“高剂量／避难所”策略受到广泛的重视．但是，这些策略来自理论数学模型和实验室数据。

Insect pests are a major cause of damage to the world's commercially important agricultural crops. Till now, 26 species of plants have been successfully transferred with insecticidal genes from Bacillus thuringiensis (Bt) to control insect pests. One of the potential risks of commercially release of Bt crops is that insect pest may well evolve resistance to Bt pesticidal proteins. The resistance mechanisms include behavioral avoidance, physiological and biochemical mechanisms and their genetic properties. Successful management for Bt resistance depends on the initial frequency of resistance alleles and genetic stability of resistance, as well as other factors. Based on genetic mathematical models and experimental data, several strategies are suggested to delay the insect resistance to Bt toxins. Among them, the ‘high dose/refuges' tactic is paid more attention for managing resistance which depends on the assumption that resistance alleles are recessive. These tactics need further assessment in the field.