Dual mode of action of Bt proteins: protoxin efficacy against resistant insects

• DOI: 10.1038/srep15107
• Publication Date: 2015-10-12T09:24:04Z
• Authors: Bruce E. Tabashnik; Min Zhang; Jeffrey A. Fabrick; Yidong Wu; Meijing Gao; Fangneng Huang; Jizhen Wei; Jie Zhang; Alexander Yelich; Gopalan C. Unnithan; Alejandra Bravo; Mario Soberón; Yves Carrière; Xianchun Li
• Keywords: Bacillus thuringiensis; Cry1Ac; Mode of Action; Bt Cotton

Abstract Transgenic crops that produce Bacillus thuringiensis (Bt) proteins for pest control are grown extensively, but insect adaptation can reduce their effectiveness. Established mode of action models assert Bt Cry1Ab and Cry1Ac produced as inactive protoxins require conversion to a smaller activated form exert toxicity. However, contrary this widely accepted paradigm, we report evidence from seven resistant strains three major crop pests showing were generally more potent than the corresponding toxins. Moreover, resistance was higher toxins in eight nine cases evaluated study. These data previously reported results support new model which kill insects via different pathways. Recognizing be against may help enhance sustain efficacy transgenic crops.