Dual mode of action of Bt proteins: protoxin efficacy against resistant insects.
Dual mode of action of Bt proteins: protoxin efficacy against resistant insects.
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Bt 蛋白的双重作用模式：原毒素对抗抗性昆虫的功效
DOI：
10.1038/srep15107
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发表时间：
2015-10-12
影响因子：
4.6
通讯作者：
Li X
中科院分区：
文献类型：
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作者：
Tabashnik BE;Zhang M;Fabrick JA;Wu Y;Gao M;Huang F;Wei J;Zhang J;Yelich A;Unnithan GC;Bravo A;Soberón M;Carrière Y;Li X
转基因作物生产苏云金杆菌（Bt）蛋白质的害虫控制广泛种植，但昆虫适应可能会降低其效力。已建立的作用模式模型断言Bt蛋白Cry1Ab和Cry1Ac是作为非活性原毒素产生的，需要转化为较小的活化形式以发挥毒性。然而，与这种被广泛接受的范式相反，我们报告了来自三种主要作物害虫的七种抗性菌株的证据，表明Cry1Ab和Cry1Ac原毒素通常比相应的活化毒素更有效。此外，在这项研究中评估的9例病例中，有8例对活化毒素的耐药性高于原毒素。这些数据和以前报道的结果支持一个新的模型，其中原毒素和活化毒素通过不同的途径杀死昆虫。认识到原毒素比活化毒素对抗性昆虫的作用更强，可能有助于提高和维持转基因Bt作物的功效。
Transgenic crops that produceBacillus thuringiensis(Bt) proteins for pest control are grown extensively, but insect adaptation can reduce their effectiveness. Established mode of action models assert that Bt proteins Cry1Ab and Cry1Ac are produced as inactive protoxins that require conversion to a smaller activated form to exert toxicity. However, contrary to this widely accepted paradigm, we report evidence from seven resistant strains of three major crop pests showing that Cry1Ab and Cry1Ac protoxins were generally more potent than the corresponding activated toxins. Moreover, resistance was higher to activated toxins than protoxins in eight of nine cases evaluated in this study. These data and previously reported results support a new model in which protoxins and activated toxins kill insects via different pathways. Recognizing that protoxins can be more potent than activated toxins against resistant insects may help to enhance and sustain the efficacy of transgenic Bt crops.