中文摘要：抗性昆虫的出现会限制转BT基因作物的可持续生产。另外，在转基因作物中非预期标记基因的存在也是一个重要的环境和健康问题。因此，无标记转基因作物的研发是抗性管理的必要条件。本文测试了Cry2Aa（D42 / k63f / k64p）基因在抗虫转基因烟草研发中的作用，利用Cre/lox介导重组方法从表达Cry2Aa（D42 / k63f / k64p）基因的转基因烟草中消除了选择性标记基因，并成功研发了表达Cry2A基因的无标记T2转基因烟草。实时免疫印迹分析表明， Cry2A基因可以在转基因植物中表达；昆虫饲养试验表明，在表达Cry2A基因的无标记T2转基因植物中棉叶虫与棉铃虫的死亡率分别为82%-92%和52%-61%。研究结果表明，Cry2Aa基因能用于抗虫转Bt基因作物品种中，并将防护由不同害虫所造成的作物损失。
外文摘要：Emergence of resistant insects limits the sustainability of Bacillus thuringiensis (Bt) transgenic crop plants for insect management. Beside this, the presence of unwanted marker gene(s) in the transgenic crops is also a major environmental and health concern. Thus, development of marker free transgenic crop plants expressing a new class of toxin having a different mortality mechanism is necessary for resistance management. In a previous study, we generated an engineered Cry2Aa (D42/K63F/K64P) toxin which has a different mortality mechanism as compared to first generation Bt toxin Cry1A, and this engineered toxin was found to enhance 4.1-6.6-fold toxicity against major lepidopteran insect pests of crop plants. In the present study, we have tested the potency of this engineered synthetic Cry2Aa (D42/K63F/K64P) toxin as a candidate in the development of insect resistant transgenic tobacco plants. Simultaneously, we have eliminated the selectable marker gene from the Cry2Aa (D42/K63F/K64P) expressing tobacco plants by exploiting the Cre/lox mediated recombination methodology, and successfully developed marker free T2 transgenic tobacco plants expressing the engineered Cry2Aa toxin. Real time and western blot analysis demonstrated the expression of engineered toxin gene in transgenic plants. Insect feeding assays revealed that the marker free T2 progeny of transgenic plants expressing Cry2Aa (D42/K63F/K64P) toxin showed 82-92 and 52-61 % mortality to cotton leaf worm (CLW) and cotton bollworm (CBW) respectively. Thus, this engineered Cry2Aa toxin could be useful for the generation of insect resistant transgenic Bt lines which will protect the crop damages caused by different insect pests such as CLW and CBW.
外文关键词：Bacillus thuringiensis；Cry2Aa；Cre/lox recombination；Selectable marker gene；GM crops；Insect resistance；Lepidopteran pests
作者：Gayen, Srimonta；Mandal, Chandi Charan；Samanta, Milan Kumar；等
作者单位：密歇根大学
期刊名称：WORLD JOURNAL OF MICROBIOLOGY & BIOTECHNOLOGY
期刊影响因子：1.532
出版年份：2016
出版刊次：4
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