Kang J, Onstad D W, Hellmich R L, Moser S E, Hutchison W D, Prasifka J R
Department of Entomology, University of Illinois, 320 Morrill Hall, 505 South Goodwin Ave., Urbana, IL 61801, USA.
Environ Entomol. 2012 Feb;41(1):200-11. doi: 10.1603/en11133.
We used a mathematical model with processes reflecting larval mortality resulting from feeding on cross-pollinated ears or Bt ears of corn to analyze the risk of evolution of Cry-toxin resistance in Ostrinia nubilalis (Hübner). In the simulations, evolution of resistance was delayed equally well by both seed mixtures and blocks with the same proportion of refuge. Our results showed that Bt-pollen drift has little impact on the evolution of Bt resistance in O. nubilalis. However, low-toxin expression in ears of transgenic corn can reduce the durability of transgenic corn expressing single toxin, whereas durability of pyramided corn hybrids is not significantly reduced. The toxin-survival rate of heterozygous larvae in Bt-corn ears expressing one or two proteins has more impact on evolution of Bt resistance in O. nubilalis than the parameters related to larval movement to Bt ears or the toxin-survival rate of the homozygous susceptible larvae in Bt ears. Bt resistance evolves slower when toxin mortality is distributed across the first two larval stadia than when only the first instars are susceptible to Bt toxins. We suggest that stakeholders examine toxin-survival rates for insect pests and take into account that instars may feed on different parts of Bt corn.
我们使用了一个数学模型，该模型中的过程反映了以异花授粉玉米穗或Bt玉米穗为食导致的幼虫死亡率，以此来分析欧洲玉米螟（Ostrinia nubilalis (Hübner)）对Cry毒素产生抗性进化的风险。在模拟中，种子混合物和具有相同避难所比例的种植区对延缓抗性进化的效果相同。我们的结果表明，Bt花粉漂移对欧洲玉米螟Bt抗性的进化影响很小。然而，转基因玉米穗中低毒素表达会降低表达单一毒素的转基因玉米的持久性，而复合性状玉米杂交种的持久性则不会显著降低。在表达一种或两种蛋白的Bt玉米穗中，杂合幼虫的毒素存活率对欧洲玉米螟Bt抗性进化的影响，比与幼虫向Bt玉米穗移动相关的参数或Bt玉米穗中纯合敏感幼虫的毒素存活率的影响更大。当毒素死亡率分布在前两个幼虫龄期时，Bt抗性的进化比仅第一龄幼虫对Bt毒素敏感时更慢。我们建议利益相关者检查害虫的毒素存活率，并考虑到不同龄期幼虫可能取食Bt玉米的不同部位。
