de la Poza Marta, Farinós Gema P, Beroiz Beatriz, Ortego Félix, Hernández-Crespo Pedro, Castañera Pedro
Departamento de Biología de Plantas, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, Madrid 28040, Spain.
Environ Entomol. 2008 Oct;37(5):1354-60. doi: 10.1603/0046-225x(2008)37[1354:gsosnl]2.0.co;2.
The Mediterranean corn borer, Sesamia nonagrioides (Lefebvre) (Lepidoptera: Noctuidae), is a major pest of maize in the Mediterranean area. Transgenic Bt maize expressing the Cry1Ab toxin from the bacterium Bacillus thuringiensis can effectively control this pest. The characterization of S. nonagrioides population structure, at a large geographical scale, would provide some insight in decision making for resistance management. The genetic relationships among nine populations from Spain, one from France, one from Italy, three from Greece, and one from Turkey were assessed using Random Amplyfied Polymorphic DNA (RAPD) markers. Populations from France and Spain formed a cluster independent from a cluster of populations collected in Italy, Turkey, and Greece in a unweighted pair-group method with arithmetic average dendrogram constructed from Nei's genetic distances. Average genetic differentiation among samples was significant for all geographical groupings analyzed (F (ST) = 0.160 +/- 0.014 for Spanish populations; 0.133 +/- 0.022 for Spanish and French populations; and 0.095 +/- 0.010 for Greek, Italian, and Turkish populations). Genetic differentiation was also significant for all paired comparisons of populations, including two Spanish populations separated by only 15 km with no apparent geographical barriers. No pattern of isolation by distance was observed among Mediterranean corn borer populations collected in Spain and France. These results suggest a limited genetic exchange between relatively distant S. nonagrioides populations in Europe, which might contribute to decreased rate of spread of resistance alleles once resistance has developed at a certain site.
地中海玉米螟（Sesamia nonagrioides (Lefebvre)，鳞翅目：夜蛾科）是地中海地区玉米的主要害虫。表达来自苏云金芽孢杆菌Cry1Ab毒素的转基因Bt玉米能够有效防治这种害虫。在大地理尺度上对地中海玉米螟种群结构进行特征分析，将为抗性管理决策提供一些见解。利用随机扩增多态性DNA（RAPD）标记评估了来自西班牙的9个种群、来自法国的1个种群、来自意大利的1个种群、来自希腊的3个种群以及来自土耳其的1个种群之间的遗传关系。在根据Nei氏遗传距离构建的非加权算术平均法聚类图中，来自法国和西班牙的种群形成了一个独立的聚类，与在意大利、土耳其和希腊收集的种群聚类不同。对于所有分析的地理分组，样本间的平均遗传分化均显著（西班牙种群的F(ST)=0.160±0.014；西班牙和法国种群的F(ST)=0.133±0.022；希腊、意大利和土耳其种群的F(ST)=0.095±0.010）。种群的所有配对比较中遗传分化也显著，包括仅相隔15公里且无明显地理障碍的两个西班牙种群。在西班牙和法国收集的地中海玉米螟种群中未观察到距离隔离模式。这些结果表明，欧洲相对遥远的地中海玉米螟种群之间的基因交流有限，这可能导致一旦在某个位点产生抗性，抗性等位基因的传播速率降低。
