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="">Bacillus thuringiensis</i> toxins.


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 16 (Page no: 173)

Resistance management for Bt maize and above-ground lepidopteran targets in the USA: from single gene to pyramided traits.

Since first being commercialized in 1996, transgenic maize expressing Bacillus thuringiensis (Bt) proteins has gained widespread acceptance in the world. In 2013, nearly 50 Mha of Bt maize were planted in 15 countries. In the same year, growers in the USA alone planted c.30 Mha of Bt maize, which accounted for 76% of the total Bt maize area of the country. Up to now, Bt maize technology can be classified into two generations. The first generation of Bt maize contains only a single Bt gene for a target. In 2010, the second generation of Bt maize became commercially available and this expresses two or more pyramided Bt proteins. Currently, the pyramided products are predominant in the USA. The major lepidopteran targets of Bt maize in the USA are corn borers (Crambidae), the corn earworm, Helicoverpa zea, and the fall armyworm, Spodoptera frugiperda. To counter the threat of insect resistance, two resistance management strategies for Bt maize, 'high dose/refuge' and gene pyramiding, have been implemented. The long-term use of Bt maize against the major agricultural pests in North America provides a good opportunity to analyse the effectiveness of the adopted insect resistance management (IRM) plans. Analysis of the available data shows that all corn borer species remain susceptible to Bt proteins and that no field resistance has occurred after nearly two decades of intensive use of Bt maize in the continent. Pyramided Bt maize is effective in controlling corn earworm and fall armyworm, although recent studies indicate that field resistance to single-gene Cry1F maize in the fall armyworm has occurred in the south-east coastal areas of the US mainland. Knowledge of the resistance management gained from the USA should be useful for other countries in their sustainable use of Bt crop technology.

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: 9 (Page no: 98) Roles of ABC proteins in the mechanism and management of Bt resistance. Author(s): Heckel, D. G.
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: 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.