Type of fitness cost influences the rate of evolution of resistance to transgenic Bt crops.
Type of fitness cost influences the rate of evolution of resistance to transgenic Bt crops.
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DOI：
10.1111/1365-2664.12680
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发表时间：
2016-10
期刊：
影响因子：
--
通讯作者：
Bonsall MB
中科院分区：
文献类型：
--
作者：
Hackett SC;Bonsall MB
害虫抗药性的演变是可持续农业面临的重大挑战。对于表达苏云金芽孢杆菌（Bt）的转基因作物，晶体（Cry）毒素抗性进化可能会被高剂量/避难所策略延迟，其中种植无毒避难所以促进易感昆虫的生存。高剂量/避难所策略可能与抗性等位基因相关的适应性成本相互作用，以进一步延迟抗性。然而，虽然在该领域报告了各种各样的健身成本，但它们通常表示为对竞争等生态条件不敏感的生存或生存能力的固定减少。此外，潜在的动态后果限制易感昆虫的避难所，这只代表了一小部分的可用空间很少被考虑。我们提出了一个广义离散时间模型，利用动态规划方法来获得最佳的管理决策控制理论昆虫害虫种群暴露于Bt作物。我们认为三种基因型（敏感纯合子，耐药纯合子和杂合子）和实施健身成本的抗性Bt毒素的相对竞争能力的抗性昆虫或作为一个惩罚的繁殖力下降。模型分析重复和对比两种类型的密度依赖：均匀的密度依赖，在整个景观和异质密度依赖的竞争强度成反比的规模与补丁大小，并分别确定为避难所和Bt作物同样运作。当Bt的种植被最佳地决定时，与降低抗性昆虫的竞争能力的同等适合性成本相比，适合性成本对繁殖力允许种植更大面积的Bt作物。异质竞争只影响模型的预测时，Bt在每个赛季的种植面积的比例是最佳的决定和抗性不是隐性的。 合成与应用。当抗性进化的限制并非不可克服时，单靠高剂量/避难所策略不足以长期保持对转基因苏云金芽孢杆菌（Bt）作物的易感性。健身成本可能会增强避难所的延迟效应，但它们这样做的程度取决于生物学上如何实现成本。适用于其他变量独立的健身成本可能更有利于阻力管理比成本，只有可见的选择在有限的生态条件下。当抗性进化的限制并非不可克服时，单靠高剂量/避难所策略不足以长期保持对转基因苏云金芽孢杆菌（Bt）作物的易感性。健身成本可能会增强避难所的延迟效果，但它们的作用程度取决于成本在生物学上的实现方式。适用于其他变量独立的健身成本可能更有利于阻力管理比成本，只有可见的选择在有限的生态条件下。
The evolution of resistance to pesticides by insect pests is a significant challenge for sustainable agriculture. For transgenic crops expressing Bacillus thuringiensis (Bt), crystalline (Cry) toxins resistance evolution may be delayed by the high‐dose/refuge strategy in which a non‐toxic refuge is planted to promote the survival of susceptible insects. The high‐dose/refuge strategy may interact with fitness costs associated with resistance alleles to further delay resistance. However, while a diverse range of fitness costs are reported in the field, they are typically represented as a fixed reduction in survival or viability which is insensitive to ecological conditions such as competition. Furthermore, the potential dynamic consequences of restricting susceptible insects to a refuge which represents only a fraction of the available space have rarely been considered. We present a generalized discrete time model which utilizes dynamic programming methods to derive the optimal management decisions for the control of a theoretical insect pest population exposed to Bt crops. We consider three genotypes (susceptible homozygotes, resistant homozygotes and heterozygotes) and implement fitness costs of resistance to Bt toxins as either a decrease in the relative competitive ability of resistant insects or as a penalty on fecundity. Model analysis is repeated and contrasted for two types of density dependence: uniform density dependence which operates equally across the landscape and heterogeneous density dependence where the intensity of competition scales inversely with patch size and is determined separately for the refuge and Bt crop. When the planting of Bt is decided optimally, fitness costs to fecundity allow for the planting of larger areas of Bt crops than equivalent fitness costs that reduce the competitive ability of resistant insects. Heterogeneous competition only influenced model predictions when the proportional area of Bt planted in each season was decided optimally and resistance was not recessive. Synthesis and applications. The high‐dose/refuge strategy alone is insufficient to preserve susceptibility to transgenic Bacillus thuringiensis (Bt) crops in the long term when constraints upon the evolution of resistance are not insurmountable. Fitness costs may enhance the delaying effect of the refuge, but the extent to which they do so depends upon how the cost is realized biologically. Fitness costs which apply independently of other variables may be more beneficial to resistance management than costs which are only visible to selection under a limited range of ecological conditions. The high‐dose/refuge strategy alone is insufficient to preserve susceptibility to transgenic Bacillus thuringiensis (Bt) crops in the long term when constraints upon the evolution of resistance are not insurmountable. Fitness costs may enhance the delaying effect of the refuge, but the extent to which they do so depends upon how the cost is realized biologically. Fitness costs which apply independently of other variables may be more beneficial to resistance management than costs which are only visible to selection under a limited range of ecological conditions.
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影响因子：
2.2
作者：
Ingber, David A.;Gassmann, Aaron J.
通讯作者：
Gassmann, Aaron J.
生物相互作用控制对毒物的遗传适应。
DOI：
10.1098/rspb.2015.0071
发表时间：
2015-05-07
期刊：
Proceedings. Biological sciences
影响因子：
--
作者：
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通讯作者：
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影响因子：
5.4
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Alphey L
影响因子：
1.6
作者：
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通讯作者：
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影响因子：
4.2
作者：
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