ABCs of Insect Resistance to Bt.

Bruce E Tabashnik

doi:10.1371/journal.pgen.1005646

Abstract

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ABCs of Insect Resistance to Bt.

Highlights

In a breakthrough that promises to accelerate progress in understanding Cry2 toxins, Tay et al, in this issue of PLOS Genetics [9], identify a gene tightly linked with resistance to Cry2Ab in Helicoverpa armigera, one of the world’s most damaging crop pests
As part of Australia’s proactive program for monitoring resistance to Bacillus thuringiensis (Bt) crops, screening of field populations for resistance to Cry2Ab began in 2002, two years before farmers there started planting Bt cotton producing this toxin in combination with Cry1Ac
Despite the 85% adoption of Bt cotton producing Cry2Ab and Cry1Ac in Australia since 2005 [7], eight years of monitoring data from the robust F1 screen method show no significant increase in the frequency of resistance to Cry2Ab (0.032 in 2007–2008 to 0.021 in 2014–2015 for H. armigera; 0.010 to 0.011 over the same eight years for H. punctigera) [21]

Summary

Introduction

In a breakthrough that promises to accelerate progress in understanding Cry2 toxins, Tay et al, in this issue of PLOS Genetics [9], identify a gene tightly linked with resistance to Cry2Ab in Helicoverpa armigera, one of the world’s most damaging crop pests. As part of Australia’s proactive program for monitoring resistance to Bt crops, screening of field populations for resistance to Cry2Ab began in 2002, two years before farmers there started planting Bt cotton producing this toxin in combination with Cry1Ac. Using a method called the F2 screen, the second generation progeny of single pairs of field-collected insects were tested on an artificial diet treated with Cry2Ab. In the first year of screening, the Australian team detected resistance to Cry2Ab in one of the 28 isofemale lines that were tested [10].

Results

Conclusion