The relatively low susceptibility ofHelicoverpa armigera to CrylAc, its history of resistance to chemical insecticides and the seasonal decline in expression of CrylAc in transgenic cotton necessitated the development...The relatively low susceptibility ofHelicoverpa armigera to CrylAc, its history of resistance to chemical insecticides and the seasonal decline in expression of CrylAc 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 CrylAc. A common feature of resistance to CrylA 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） ofH. armigera and Helicoverpa punctigera was undertaken. The binding affinity for CrylAc was higher than for CrylAb, matching their relative toxicities, and CrylAc and CrylAb were found to share at least one binding site in both I-1. armigera and I-1. punctigera. However Cry2Aa did not compete with CrylAc for binding and so could be used in transgenic cotton in combination with CrylAc to control H. armigera and manage resistance. Variation in the susceptibilities of three different H. armigera strains to CrylAc correlated with the parameter Bmax/Kcom.展开更多
The cotton bollworm Helicoverpa armigera and the oriental tobacco budworm H. assulta are sibling species, both being important agricultural pests. Morphologically, the two insects are almost indistinguishable at the e...The cotton bollworm Helicoverpa armigera and the oriental tobacco budworm H. assulta are sibling species, both being important agricultural pests. Morphologically, the two insects are almost indistinguishable at the egg, larval and pupal stages. One of the big challenges in the study of these insects, in particular in integrated pest management, is a timely and dependable identification of these insects at their early stages of development. Here, we report a H. armigera-specific nuclear DNA marker, and demonstrate that it can be employed to reliably discriminate between 1-1. armigera and 11. assulta by simple polymerase chain reaction amplification experiment.展开更多
文摘The relatively low susceptibility ofHelicoverpa armigera to CrylAc, its history of resistance to chemical insecticides and the seasonal decline in expression of CrylAc 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 CrylAc. A common feature of resistance to CrylA 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） ofH. armigera and Helicoverpa punctigera was undertaken. The binding affinity for CrylAc was higher than for CrylAb, matching their relative toxicities, and CrylAc and CrylAb were found to share at least one binding site in both I-1. armigera and I-1. punctigera. However Cry2Aa did not compete with CrylAc for binding and so could be used in transgenic cotton in combination with CrylAc to control H. armigera and manage resistance. Variation in the susceptibilities of three different H. armigera strains to CrylAc correlated with the parameter Bmax/Kcom.
文摘The cotton bollworm Helicoverpa armigera and the oriental tobacco budworm H. assulta are sibling species, both being important agricultural pests. Morphologically, the two insects are almost indistinguishable at the egg, larval and pupal stages. One of the big challenges in the study of these insects, in particular in integrated pest management, is a timely and dependable identification of these insects at their early stages of development. Here, we report a H. armigera-specific nuclear DNA marker, and demonstrate that it can be employed to reliably discriminate between 1-1. armigera and 11. assulta by simple polymerase chain reaction amplification experiment.
