对小菜蛾协同增效的Cry1和Cry9类蛋白组合的筛选

Screening of synergistic combination between Cry1 and Cry9 toxins against Plutella xylostella

为筛选对小菜蛾具有协同增效作用的苏云金芽胞杆菌Cry蛋白组合,本研究在单独测定对重要蔬菜害虫小菜蛾具有高毒力的Cry1Ai、Cry1Ea和Cry9Aa蛋白杀虫活性的基础上,把Cry1Ai+Cry1Ea、Cry1Ea+Cry9Aa、Cry1Ai+Cry9Aa蛋白进行不同比例的混配,测定其对小菜蛾的毒杀作用。结果发现Cry1Ai+Cry1Ea有相加作用。Cry1Ea+Cry9Aa蛋白和Cry1Ai+Cry9Aa蛋白均在1∶1混配时增效因子最高,分别为6.67和9.06;后两种组合表现出了显著的协同增效作用。本研究获得的两种高效组合将为转基因抗虫植物的研发提供新的基因来源,有望在治理对Cry1A类蛋白产生抗性的害虫中发挥重要的作用。

In order to screen synergistic combination between Cry1 and Cry9 toxins against Plutella xylostella, Cry1Ai, Cry1Ea and Cry9Aa with a high toxicity to P. xylostella, an important insect pest of vegetables, were chosen as candidate proteins, and three combinations, Cry1Ai ＋ Cry1Ea, Cry1Ea q- Cry9Aa and Cry1Ai ＋ Cry9Aa with different ratios, were assayed against the 2nd instar larvae of P. xylostella. The results indicated that an additive effect was revealed with a mixture of Cry1Ai ＋ Cry1Ea proteins. When the ratio of Cry1Ea and Cry9Aa toxins was 1 ： 1, the synergistic factor was biggest at 6.67, and the synergistic factor for the combination between Cry1Ai and Cry9Aa was 9.06. The significant synergisms of Cry1Ea ＋ Cry9Aa and Cry1Ai ＋ Cry9Aa were found. The two high-toxicity combinations of Cry proteins obtained in this study may be new sources for development of new transgenic crops resistant to pest insects, and they might play crucial roles against certain insect pests resisted to Cry1A proteins.