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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...

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Chapter 14 (Page no: 150)

Countering pest resistance with genetically modified Bt toxins.

Insecticidal crystalline (Cry) toxins from the bacterium Bacillus thuringiensis (Bt) used in sprays and transgenic crop plants have provided major benefits for pest control, including decreased reliance on broad-spectrum chemical insecticides. However, extensive use of Bt toxins has selected for resistance, thus reducing or eliminating these benefits against some populations of at least seven species of major crop pests. This chapter reviews efforts to counter pest resistance to native Bt toxins with genetically engineered toxins called Cry1AbMod and Cry1AcMod. We generated these modified toxins by trimming the genes encoding the native toxins Cry1Ab and Cry1Ac so they lack the nucleotides that code for a portion of the amino-terminal end of the protein, including helix α-1 and part of helix α-2. Consistent with the sequential binding model for the mode of action of the toxins, the Cry1AMod toxins formed oligomers without binding to cadherin, but the native toxins required cadherin for oligomer formation. The modified toxins were more potent than the corresponding native toxins in 13 of 19 pairwise comparisons with 12 resistant strains of nine species of Lepidoptera, including field-selected strains of Plutella xylostella, Trichoplusia ni and Spodoptera frugiperda. The potency of modified toxins relative to native toxins in these resistant strains did not depend on the resistance mechanism. Against susceptible strains, the modified toxins were less effective than their native counterparts in nearly all cases. Transgenic tobacco plants producing Cry1AbMod killed larvae of Manduca sexta, which represents progress towards commercial use of the modified toxins for pest management.

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: 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.

Chapter details

  • Author Affiliation
  • Departamento Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, C.P. 62210, Cuernavaca, Morelos, Mexico.
  • Year of Publication
  • 2015
  • ISBN
  • 9781780644370
  • Record Number
  • 20153137257