title: Evidence of field-evolved resistance of Spodoptera frugiperda to Bt corn expressing Cry1F in Brazil that is still sensitive to modified Bt toxins.
abstract: Brazil ranked second only to the United States in hectares planted to genetically modified crops in 2013. Recently corn producers in the Cerrado region reported that the control of Spodoptera frugiperda with Bt corn expressing Cry1Fa has decreased, forcing them to use chemicals to reduce the damage caused by this insect pest. A colony of S. frugiperda was established from individuals collected in 2013 from Cry1Fa corn plants (SfBt) in Brazil and shown to have at least more than ten-fold higher resistance levels compared with a susceptible colony (Sflab). Laboratory assays on corn leaves showed that in contrast to SfLab population, the SfBt larvae were able to survive by feeding on Cry1Fa corn leaves. The SfBt population was maintained without selection for eight generations and shown to maintain high levels of resistance to Cry1Fa toxin. SfBt showed higher cross-resistance to Cry1Aa than to Cry1Ab or Cry1Ac toxins. As previously reported, Cry1A toxins competed the binding of Cry1Fa to brush border membrane vesicles (BBMV) from SfLab insects, explaining cross-resistance to Cry1A toxins. In contrast Cry2A toxins did not compete Cry1Fa binding to SfLab-BBMV and no cross-resistance to Cry2A was observed, although Cry2A toxins show low toxicity to S. frugiperda. Bioassays with Cry1AbMod and Cry1AcMod show that they are highly active against both the SfLab and the SfBt populations. The bioassay data reported here show that insects collected from Cry1Fa corn in the Cerrado region were resistant to Cry1Fa suggesting that resistance contributed to field failures of Cry1Fa corn to control S. frugiperda.
authors.affiliation: Embrapa Recursos Genéticos e Biotecnologia, Brasília, Distrito Federal, Brazil.
authors.forename: Rose
authors.initials: R
authors.lastname: Monnerat
authors.affiliation: Instituto Mato-Grossense do Algodão, Cuiabá, Mato Grosso, Brazil.
authors.forename: Erica
authors.initials: E
authors.lastname: Martins
authors.affiliation: Embrapa Recursos Genéticos e Biotecnologia, Brasília, Distrito Federal, Brazil; Departamento de Microbiologia, Universidade de Brasília, Brasília, Distrito Federal, Brazil.
authors.forename: Cristina
authors.initials: C
authors.lastname: Macedo
authors.affiliation: Instituto Mato-Grossense do Algodão, Cuiabá, Mato Grosso, Brazil.
authors.forename: Paulo
authors.initials: P
authors.lastname: Queiroz
authors.affiliation: Embrapa Recursos Genéticos e Biotecnologia, Brasília, Distrito Federal, Brazil.
authors.forename: Lilian
authors.initials: L
authors.lastname: Praça
authors.affiliation: Instituto Mato-Grossense do Algodão, Cuiabá, Mato Grosso, Brazil.
authors.forename: Carlos Marcelo
authors.initials: CM
authors.lastname: Soares
authors.affiliation: Embrapa Recursos Genéticos e Biotecnologia, Brasília, Distrito Federal, Brazil.
authors.forename: Helio
authors.initials: H
authors.lastname: Moreira
authors.affiliation: Embrapa Recursos Genéticos e Biotecnologia, Brasília, Distrito Federal, Brazil.
authors.forename: Isabella
authors.initials: I
authors.lastname: Grisi
authors.affiliation: Embrapa Recursos Genéticos e Biotecnologia, Brasília, Distrito Federal, Brazil.
authors.forename: Joseane
authors.initials: J
authors.lastname: Silva
authors.affiliation: Instituto de Biotecnologia, Universidad Nacional Autonoma de México, Cuernavaca, Morellos, Mexico.
authors.forename: Mario
authors.initials: M
authors.lastname: Soberon
authors.affiliation: Instituto de Biotecnologia, Universidad Nacional Autonoma de México, Cuernavaca, Morellos, Mexico.
authors.forename: Alejandra
authors.initials: A
authors.lastname: Bravo
mesh_terms: D000818:Animals; D001413:Bacillus thuringiensis / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics / Q000494:pharmacology*; D001427:Bacterial Toxins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D001681:Biological Assay; D019921:Biotinylation; D001938:Brazil; D007425:Intracellular Membranes / Q000378:metabolism; D008871:Microvilli / Q000378:metabolism; D030821:Plants, Genetically Modified; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D018411:Spodoptera / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D016019:Survival Analysis; D003313:Zea mays / Q000235:genetics* / Q000382:microbiology
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D011994:Recombinant Proteins
references.citation: Toxins (Basel). 2014 Aug;6(8):2239-55
references.pmid: 25089349
references.citation: PLoS One. 2009;4(5):e5545
references.pmid: 19440244
references.citation: Science. 2007 Dec 7;318(5856):1640-2
references.pmid: 17975031
references.citation: Gene. 1991 Dec 1;108(1):115-9
references.pmid: 1662180
references.citation: Biochemistry. 2002 May 14;41(19):6178-84
references.pmid: 11994014
references.citation: Pest Manag Sci. 2011 Aug;67(8):898-903
references.pmid: 21438121
references.citation: Appl Environ Microbiol. 2001 Jan;67(1):323-9
references.pmid: 11133462
references.citation: Appl Environ Microbiol. 2005 Sep;71(9):5627-9
references.pmid: 16151165
references.citation: PLoS One. 2011;6(7):e22629
references.pmid: 21829470
references.citation: Appl Environ Microbiol. 2006 Nov;72(11):7029-35
references.pmid: 16936049
references.citation: Proc Biol Sci. 2003 Nov 7;270(1530):2263-70
references.pmid: 14613613
references.citation: Appl Environ Microbiol. 1999 Feb;65(2):457-64
references.pmid: 9925568
references.citation: Biochem J. 2014 Apr 15;459(2):383-96
references.pmid: 24456341
references.citation: PLoS One. 2011;6(8):e22874
references.pmid: 21857961
references.citation: J Biol Chem. 2009 Nov 20;284(47):32750-7
references.pmid: 19808680
references.citation: J Econ Entomol. 2010 Aug;103(4):1031-8
references.pmid: 20857709
references.citation: Annu Rev Entomol. 2002;47:501-33
references.pmid: 11729083
references.citation: J Biol Chem. 2007 Jul 20;282(29):21222-9
references.pmid: 17537728
references.citation: Experientia. 1990 May 15;46(5):475-7
references.pmid: 2161350
references.citation: Nat Biotechnol. 2008 Feb;26(2):199-202
references.pmid: 18259177
references.citation: J Cell Sci. 1983 Mar;60:181-97
references.pmid: 6874728
references.citation: J Invertebr Pathol. 2014 Oct;122:52-4
references.pmid: 25218399
references.citation: Appl Environ Microbiol. 2008 May;74(9):2565-72
references.pmid: 18326669
references.citation: Nat Biotechnol. 2013 Jun;31(6):510-21
references.pmid: 23752438
references.citation: J Invertebr Pathol. 1996 Nov;68(3):203-12
references.pmid: 8931361
references.citation: PLoS One. 2013;8(7):e68164
references.pmid: 23861865
references.citation: Appl Environ Microbiol. 1994 Dec;60(12):4627-9
references.pmid: 16349471
references.citation: Nat Biotechnol. 2011 Dec;29(12):1128-31
references.pmid: 21983521
references.citation: Trends Microbiol. 2010 May;18(5):189-94
references.pmid: 20338765