Journal of Economic Entomology (2007) 100, 909-915

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Shudong Luo, Kongming Wu, Yan Tian, Gemei Liang, Xue Feng, Jie Zhang and Yuyuan Guo (2007)
Cross-resistance studies of Cry1Ac-resistant strains of Helicoverpa armigera (Lepidoptera: Noctuidae) to Cry2Ab
Journal of Economic Entomology 100 (3), 909-915
Abstract: Bioassays and binding tests between Cry toxins (Cry1Aa, Cry1Ab, Cry1Ac, and Cry2Ab) and brush-border membrane vesicles (BBMVs) from larvae of a Bacillus thurningiensis (Bt)-susceptible (96S) and two Cry1Ac-resistant strains (BtR and LFR10) were conducted for investigating cross-resistance of Cry1Ac-resistant strains to Cry2Ab in Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae). The resistance ratio (RR) values of the BtR and LFR10 strains to Cry1Ac and Cry2Ab were 2,971- and 1.1-fold and 253- and 1.0-fold, respectively, indicating that there was no cross-resistance to Cry2Ab. The binding experiments between Cry toxins and BBMVs from BtR, LFR10, and 96S larvae showed that all of the toxins could bind with these BBMVs, but the Cry2Ab could not displace 125I labeled Cry1Ac and Cry1Ab. The same results were observed in reciprocal binding tests, demonstrating that Cry1A and Cry2Ab had different binding sites in H. armigera and providing a potential mechanism for the lack of cross-resistance between Cry1A and Cry2Ab toxins. These results suggest that the transgenic cotton, Gossypium hirsutum L., expressing Cry1Ac and Cry2Ab genes may be deployed for management of Cry1Ac resistant H. armigera.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Kong Ming Wu, Jie Zhang, Ge-Mei Liang, Yu Yuan Guo

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
resistance/tolerance/defence of host


Pest and/or beneficial records:

Beneficial Pest/Disease/Weed Crop/Product Country Quarant.


Helicoverpa armigera Cotton (Gossypium)
Bacillus thuringiensis genes in crops (entomopathogen) Helicoverpa armigera Cotton (Gossypium)
Bacillus thuringiensis Cry1A-toxin (entomopathogen) Helicoverpa armigera Cotton (Gossypium)
Bacillus thuringiensis Cry2A-toxin (entomopathogen) Helicoverpa armigera Cotton (Gossypium)