Impact of violated high-dose refuge assumptions on evolution of Bt resistance.
Impact of violated high-dose refuge assumptions on evolution of Bt resistance.
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DOI：
10.1111/eva.12355
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发表时间：
2016-04
影响因子：
4.1
通讯作者：
Van den Berg J
中科院分区：
文献类型：
--
作者：
Campagne P;Smouse PE;Pasquet R;Silvain JF;Le Ru B;Van den Berg J
表达苏云金芽孢杆菌（Bt）毒素的转基因作物已被广泛且成功地用于控制目标害虫，同时允许大幅减少杀虫剂的使用。抗性的进化（对Bt毒素的敏感性的可遗传降低）可能对目标害虫的持续控制构成威胁，但高剂量避难所（HDR）管理策略是延迟Bt抗性抵消进化的关键。HDR策略依赖于敏感和抗性个体之间的交配频率，因此抗性等位基因的部分显性或害虫种群本身的非随机交配可以提高抗性进化的速度。使用经典的Wright-Fisher遗传模型，我们研究了偏离标准避难所模型假设对害虫种群抗性进化的影响。我们表明，当Bt选择是强的，甚至偏离随机交配和/或严格隐性电阻，低于检测阈值可以产生显着增加的速度电阻进化。每当模型违反的数量级超过抗性等位基因的初始频率时，抗性进化就会加速。我们还表明，存在一个健身成本的抗性个体的庇护作物不能很容易地克服违反HDR假设的影响。我们提出了一个参数明确的框架，使各种领域的情况和模型推理的比较。使用这个模型，我们提出了新的经验估计的速度的阻力演变（和时间失去控制），其简单的计算依赖于所观察到的变化阻力等位基因频率。
Transgenic crops expressing Bacillus thuringiensis (Bt) toxins have been widely and successfully deployed for the control of target pests, while allowing a substantial reduction in insecticide use. The evolution of resistance (a heritable decrease in susceptibility to Bt toxins) can pose a threat to sustained control of target pests, but a high‐dose refuge (HDR) management strategy has been key to delaying countervailing evolution of Bt resistance. The HDR strategy relies on the mating frequency between susceptible and resistant individuals, so either partial dominance of resistant alleles or nonrandom mating in the pest population itself could elevate the pace of resistance evolution. Using classic Wright‐Fisher genetic models, we investigated the impact of deviations from standard refuge model assumptions on resistance evolution in the pest populations. We show that when Bt selection is strong, even deviations from random mating and/or strictly recessive resistance that are below the threshold of detection can yield dramatic increases in the pace of resistance evolution. Resistance evolution is hastened whenever the order of magnitude of model violations exceeds the initial frequency of resistant alleles. We also show that the existence of a fitness cost for resistant individuals on the refuge crop cannot easily overcome the effect of violated HDR assumptions. We propose a parametrically explicit framework that enables both comparison of various field situations and model inference. Using this model, we propose novel empiric estimators of the pace of resistance evolution (and time to loss of control), whose simple calculation relies on the observed change in resistance allele frequency.