title: Optimizing pyramided transgenic Bt crops for sustainable pest management.
abstract: Transgenic crop pyramids producing two or more Bacillus thuringiensis (Bt) toxins that kill the same insect pest have been widely used to delay evolution of pest resistance. To assess the potential of pyramids to achieve this goal, we analyze data from 38 studies that report effects of ten Bt toxins used in transgenic crops against 15 insect pests. We find that compared with optimal low levels of insect survival, survival on currently used pyramids is often higher for both susceptible insects and insects resistant to one of the toxins in the pyramid. Furthermore, we find that cross-resistance and antagonism between toxins used in pyramids are common, and that these problems are associated with the similarity of the amino acid sequences of domains II and III of the toxins, respectively. This analysis should assist in future pyramid design and the development of sustainable resistance management strategies.
authors.affiliation: Department of Entomology, The University of Arizona, Tucson, Arizona, USA.
authors.forename: Yves
authors.initials: Y
authors.lastname: Carrière
authors.affiliation: School of Life Sciences, University of Sussex, Brighton, UK.
authors.forename: Neil
authors.initials: N
authors.lastname: Crickmore
authors.affiliation: Department of Entomology, The University of Arizona, Tucson, Arizona, USA.
authors.forename: Bruce E
authors.initials: BE
authors.lastname: Tabashnik
mesh_terms: D000595:Amino Acid Sequence / Q000235:genetics; D000818:Animals; D001413:Bacillus thuringiensis / Q000235:genetics; D001427:Bacterial Toxins / Q000096:biosynthesis / Q000235:genetics*; D018556:Crops, Agricultural / Q000235:genetics / Q000254:growth & development*; D007313:Insecta / Q000472:pathogenicity; D007305:Insecticide Resistance / Q000235:genetics*; D010572:Pest Control, Biological; D030821:Plants, Genetically Modified / Q000235:genetics / Q000254:growth & development
chemical_list: D001427:Bacterial Toxins