Insect Science (2005) 12, 231-240
Chunyan Liao, Liz Brooks, Stephen C. Trowell and Raymond J. Akhurst (2005)
Binding of Cry delta-endotoxins to brush border membrane vesicles of Helicoverpa armigera and Helicoverpa punctigera (Lepidoptera: Noctuidae)
Insect Science 12 (4), 231-240
Abstract: The relatively low susceptibility of Helicoverpa armigera to Cry 1 Ac, its history of resistance to chemical insecticides and the seasonal decline in expression of Cry 1 Ac in transgenic cotton necessitated the development of cotton expressing two insecticidal proteins to provide sustainable control of this multinational pest. To manage the resistance issue, it was essential that the second insecticidal protein have a significantly different mode of action to Cry1 Ac. A common feature of resistance to Cry1 A proteins in several species as well as H. armigera has been a change in the binding site. A study of binding sites for some Cry proteins in the brush border membrane vesicles (BBMV) of H. armigera and Helicoverpa punctigera was undertaken. The binding affinity for Cry1Ac was higher than for Cry1Ab, matching their relative toxicities, and Cry1Ac and Cry1Ab were found to share at least one binding site in both H. armigera and H. punctigera. However Cry2Aa did not compete with Cry 1 Ac for binding and so could be used in transgenic cotton in combination with Cry 1 Ac to control H. armigera and manage resistance. Variation in the susceptibilities of three different H. armigera strains to Cry 1 Ac correlated with the parameter Bmax/Kcom.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
general biology - morphology - evolution
resistance/tolerance/defence of host
