Data from: Genetic hitchhiking and resistance evolution to transgenic Bt toxins: insights from the African stalk borer Busseola fusca (Noctuidae)

Since transgenic crops expressing Bacillus thuringiensis (Bt) toxins were first released, resistance evolution leading to failure in control of pests populations has been observed in a number of species. Field resistance of the moth Busseola fusca was acknowledged 8 years after Bt maize was introduced in South Africa. Since then, field resistance of this corn borer has been observed at several locations, raising questions about the nature, distribution and dynamics of the resistance trait. Using genetic markers, our study identified four outlier loci clearly associated with resistance. In addition, genetic structure at neutral loci reflected extensive gene flow among populations. A realistically parameterised model suggests that resistance could travel in space at speed of several kilometres a year. Markers at outlier loci delineated a geographic region associated with resistance spread. This was an area of approximately 100 km radius, including the location where resistance was first reported. Controlled crosses corroborated these findings and showed significant differences of progeny survival on Bt plants depending on the origin of the resistant parent. Last, our study suggests diverse resistance mutations, which would explain the widespread occurrence of resistant larvae in Bt fields across the main area of maize production in South Africa.自表达苏云金芽孢杆菌（Bacillus thuringiensis，Bt）毒素的转基因作物首次释放以来，已有多个害虫物种演化出抗性，导致田间虫害防控失效。南非转Bt玉米推广8年后，非洲玉米蛀茎夜蛾（Busseola fusca）的田间抗性被正式确认。此后，多个监测点位均报道了该玉米螟的田间抗性，引发了学界关于抗性性状的本质、分布及动态的诸多疑问。本研究利用遗传标记技术，明确鉴定出4个与抗性显著关联的异常位点（outlier loci）。此外，中性位点的遗传结构分析显示，不同种群间存在广泛的基因流。通过参数设置贴合实际情况的模型模拟，结果表明抗性可在空间上以每年数公里的速度扩散。异常位点的遗传标记可勾勒出与抗性扩散相关的地理区域——该区域半径约100公里，涵盖了首例抗性被报道的点位。控制性杂交实验进一步验证了上述结论，结果显示后代在Bt植株上的存活率存在显著差异，且该差异取决于抗性亲本的来源。最后，本研究提示抗性突变具有多样性，这也解释了南非玉米主产区的转Bt玉米田中为何广泛存在抗性幼虫。