title: Uptake and transfer of a Bt toxin by a Lepidoptera to its eggs and effects on its offspring.
abstract: Research on non-target effects of transgenic crop plants has focused primarily on bitrophic, tritrophic and indirect effects of entomotoxins from Bacillus thuringiensis, but little work has considered intergenerational transfer of Cry proteins. This work reports a lepidopteran (Chlosyne lacinia) taking up a Bt entomotoxin when exposed to sublethal or low concentrations, transferring the entomotoxin to eggs, and having adverse effects on the first filial generation (F1) offspring. Two bioassays were conducted using a sublethal concentration of toxin (100.0 ng/µl Cry1Ac) for adults and a concentration equal to the LC10 (2.0 ng/µl Cry1Ac) for larvae. Cry1Ac is the most common entomotoxin expressed in Bt cotton in Brazil. In the adult diet bioassay there was no adverse effect on the parental generation (P0) adults, but the F1 larvae had higher mortality and longer development time compared to F1 larvae of parents that did not ingest Cry1Ac. For the 3rd instar larvae, there was no measurable effect on the P0 larvae, pupae and adults, but the F1 larvae had higher mortality and longer development time. Using chemiluminescent Western Blot, Cry1Ac was detected in F1 eggs laid by P0 butterflies from both bioassays. Our study indicates that, at least for this species and these experimental conditions, a ∼65 kDa insecticidal protein can be taken up and transferred to descendants where it can increase mortality and development time.
authors.affiliation: Department of Biological Control, Embrapa Genetic Resources and Biotechnology, Brasília, DF, Brazil.
authors.forename: Débora Pires
authors.initials: DP
authors.lastname: Paula
authors.affiliation: Department of Entomology, University of Minnesota, St. Paul, Minnesota, United States of America.
authors.forename: David A
authors.initials: DA
authors.lastname: Andow
authors.affiliation: Department of Molecular Biology, University of Brasilia, Brasília, DF, Brazil.
authors.forename: Renata Velozo
authors.initials: RV
authors.lastname: Timbó
authors.affiliation: Department of Biological Control, Embrapa Genetic Resources and Biotechnology, Brasília, DF, Brazil.
authors.forename: Edison R
authors.initials: ER
authors.lastname: Sujii
authors.affiliation: Department of Biological Control, Embrapa Genetic Resources and Biotechnology, Brasília, DF, Brazil.
authors.forename: Carmen S S
authors.initials: CS
authors.lastname: Pires
authors.affiliation: Department of Biological Control, Embrapa Genetic Resources and Biotechnology, Brasília, DF, Brazil.
authors.forename: Eliana M G
authors.initials: EM
authors.lastname: Fontes
mesh_terms: D000818:Animals; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000378:metabolism* / Q000633:toxicity; D001681:Biological Assay; D004531:Eggs; D004731:Endotoxins / Q000378:metabolism* / Q000633:toxicity; D005260:Female; D006460:Hemolysin Proteins / Q000378:metabolism* / Q000633:toxicity; D007814:Larva / Q000187:drug effects; D007915:Lepidoptera / Q000254:growth & development / Q000378:metabolism*; D030821:Plants, Genetically Modified
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis
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