Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

CABI Book Chapter

Bt resistance: characterization and strategies for GM crops producing Bacillus thuringiensis toxins.

Book cover for Bt resistance: characterization and strategies for GM crops producing <i xmlns="http://www.w3.org/1999/xhtml">Bacillus thuringiensis</i> toxins.

Description

This book focuses on descriptions of the extent of use of Bacillus thuringiensis (Bt) crops and the emerging problem of resistance, recent progress in elucidating the mechanism of action of Bt toxins and describing the different resistance mechanisms and strategies for coping with resistance in the field. There are four sections. In the first section ('The extent of use of Bt crops and the emergin...

Chapter 9 (Page no: 98)

Roles of ABC proteins in the mechanism and management of Bt resistance.

Genetic studies of strains of insects that have developed resistance to pore-forming Cry toxins from Bacillus thuringiensis (Bt) have provided useful and unexpected insights into the mode of action of the toxin. Independent approaches in five species of Lepidoptera have converged on the same result: that mutations in a member of the superfamily of ABC transporters confer resistance to Cry toxins. These mutations range from a single amino acid insertion to truncations that delete most of the protein. This result is surprising, because since the first detection of the specific binding of Cry toxins to sites in the lepidopteran midgut in 1988, no studies had documented any sort of interaction between Cry toxins and ABC proteins. It is hypothesized that ABC transporters mediate the critical step of Cry pore insertion into the membrane. Heterologous expression of ABC proteins has recently shown that they can facilitate cell swelling by Cry toxins, which is indirect evidence of pore formation. It is suggested that the 'ATP-switch' mechanism of ABC proteins that drives the transport of small molecules across cell membranes might be exploited to potentiate Bt action and to guide the design of improved Cry toxins.

Other chapters from this book

Chapter: 1 (Page no: 1) Successes and failures of transgenic Bt crops: global patterns of field-evolved resistance. Author(s): Tabashnik, B. E., Carrière, Y.
Chapter: 2 (Page no: 15) Status of resistance to Bt cotton in China: cotton bollworm and pink bollworm. Author(s): Gao YuLin, Liu ChenXi, Wu YiDong, Wu KongMing
Chapter: 3 (Page no: 26) Insect resistance to Bt toxins in Brazil and Latin America. Author(s): Monnerat, R., Martins, E., Queiroz, P., Praça, L., Soares, C. M.
Chapter: 4 (Page no: 36) Resistance of Busseola fusca to Cry1Ab Bt maize plants in South Africa and challenges to insect resistance management in Africa. Author(s): Berg, J. van den, Campagne, P.
Chapter: 5 (Page no: 49) Resistance of cabbage loopers to Btk in a greenhouse setting: occurrence, spread and management. Author(s): Janmaat, A., Franklin, M., Myers, J. H.
Chapter: 6 (Page no: 56) Different models of the mode of action of Bt 3d-Cry toxins. Author(s): Bravo, A., Gómez, I., Mendoza, G., Gaytán, M., Soberón, M.
Chapter: 7 (Page no: 69) Roles of insect midgut cadherin in Bt intoxication and resistance. Author(s): Fabrick, J. A., Wu YiDong
Chapter: 8 (Page no: 87) Mechanism of Cry1Ac resistance in cabbage loopers - a resistance mechanism selected in insect populations in an agricultural environment. Author(s): Wang, P.
Chapter: 10 (Page no: 107) The role of proteolysis in the biological activity of Bt insecticidal crystal proteins. Author(s): Zalunin, I. A., Elpidina, E. N., Oppert, B.
Chapter: 11 (Page no: 119) The lessons that Caenorhabditis elegans has taught us about the mechanism of action of crystal proteins. Author(s): Sitaram, A., Aroian, R. V.
Chapter: 12 (Page no: 126) The development and prospect of discovery of Bt toxin genes. Author(s): Zhang Jie, Shu ChangLong, Wang ZeYu
Chapter: 13 (Page no: 138) Cry toxin binding site models and their use in strategies to delay resistance evolution. Author(s): Jakka, S., Ferré, J., Jurat-Fuentes, J. L.
Chapter: 14 (Page no: 150) Countering pest resistance with genetically modified Bt toxins. Author(s): Soberón, M., García-Gómez, B. I., Pacheco, S., Sánchez, J., Tabashnik, B. E., Bravo, A.
Chapter: 15 (Page no: 162) RNA interference strategy for crop protection against insect pests. Author(s): Sneha Yogindran, Rajam, M. V.
Chapter: 16 (Page no: 173) Resistance management for Bt maize and above-ground lepidopteran targets in the USA: from single gene to pyramided traits. Author(s): Huang, F. N.
Chapter: 17 (Page no: 186) Insect resistance management and integrated pest management for Bt crops: prospects for an area-wide view. Author(s): Hutchison, W. D.