title: Resistance to dual-gene Bt maize in Spodoptera frugiperda: selection, inheritance, and cross-resistance to other transgenic events.
abstract: Transgenic crop "pyramids" producing two or more Bacillus thuringiensis (Bt) toxins active against the same pest are used to delay evolution of resistance in insect pest populations. Laboratory and greenhouse experiments were performed with fall armyworm, Spodoptera frugiperda, to characterize resistance to Bt maize producing Cry1A.105 and Cry2Ab and test some assumptions of the "pyramid" resistance management strategy. Selection of a field-derived strain of S. frugiperda already resistant to Cry1F maize with Cry1A.105 + Cry2Ab maize for ten generations produced resistance that allowed the larvae to colonize and complete the life cycle on these Bt maize plants. Greenhouse experiments revealed that the resistance was completely recessive (Dx = 0), incomplete, autosomal, and without maternal effects or cross-resistance to the Vip3Aa20 toxin produced in other Bt maize events. This profile of resistance supports some of the assumptions of the pyramid strategy for resistance management. However, laboratory experiments with purified Bt toxin and plant leaf tissue showed that resistance to Cry1A.105 + Cry2Ab2 maize further increased resistance to Cry1Fa, which indicates that populations of fall armyworm have high potential for developing resistance to some currently available pyramided maize used against this pest, especially where resistance to Cry1Fa was reported in the field.
authors.affiliation: Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil.
authors.forename: Oscar F
authors.initials: OF
authors.lastname: Santos-Amaya
authors.affiliation: Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil.
authors.forename: João V C
authors.initials: JV
authors.lastname: Rodrigues
authors.affiliation: Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil.
authors.forename: Thadeu C
authors.initials: TC
authors.lastname: Souza
authors.affiliation: Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil.
authors.forename: Clébson S
authors.initials: CS
authors.lastname: Tavares
authors.affiliation: Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil.
authors.forename: Silverio O
authors.initials: SO
authors.lastname: Campos
authors.affiliation: Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil.
authors.forename: Raul N C
authors.initials: RN
authors.lastname: Guedes
authors.affiliation: Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil.|Instituto Nacional de Ciência e Tecnologia em Interações Planta-Praga, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil.
authors.forename: Eliseu J G
authors.initials: EJ
authors.lastname: Pereira
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology; D060467:Disease Resistance / Q000235:genetics*; D004351:Drug Resistance / Q000235:genetics; D004731:Endotoxins / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology; D005260:Female; D056084:Genetic Fitness / Q000235:genetics; D006460:Hemolysin Proteins / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology; D006790:Host-Parasite Interactions / Q000235:genetics; D040582:Inheritance Patterns; D008297:Male; D010935:Plant Diseases / Q000235:genetics* / Q000469:parasitology; D030821:Plants, Genetically Modified; D012641:Selection, Genetic; D018411:Spodoptera / Q000235:genetics* / Q000502:physiology; D003313:Zea mays / Q000235:genetics* / Q000378:metabolism / Q000469:parasitology
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis