title: Is the mature endotoxin Cry1Ac from Bacillus thuringiensis inactivated by a coagulation reaction in the gut lumen of resistant Helicoverpa armigera larvae?
abstract: Bacillus thuringiensis endotoxins (Bt-toxins) are the most important biopesticides used in controlling insect pests and vectors of diseases. The emergence of widespread resistance to Bt in some insect species is a serious threat to agricultural production. Analysis of Bt-resistant and susceptible laboratory strains of Helicoverpa armigera revealed elevated immune responses involving increased melanization and the presence of a soluble toxin-binding glycoprotein in the hemolymph and gut lumen of the resistant strain. We propose a resistance mechanism against toxins based on a systemic immune-induction that can be transmitted to the next generation by a maternal effect.
authors.affiliation: Insect Molecular Biology, School of Agriculture and Wine, University of Adelaide, Glen Osmond, SA 5064, Australia.
authors.forename: Gang
authors.initials: G
authors.lastname: Ma
authors.forename: Harry
authors.initials: H
authors.lastname: Roberts
authors.forename: Muhammad
authors.initials: M
authors.lastname: Sarjan
authors.forename: Nicki
authors.initials: N
authors.lastname: Featherstone
authors.forename: Jelle
authors.initials: J
authors.lastname: Lahnstein
authors.forename: Ray
authors.initials: R
authors.lastname: Akhurst
authors.forename: Otto
authors.initials: O
authors.lastname: Schmidt
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000378:metabolism / Q000494:pharmacology*; D001427:Bacterial Toxins / Q000378:metabolism / Q000494:pharmacology*; D003433:Crosses, Genetic; D004731:Endotoxins / Q000378:metabolism / Q000494:pharmacology*; D041981:Gastrointestinal Tract / Q000276:immunology / Q000378:metabolism; D006460:Hemolysin Proteins; D019476:Insect Proteins / Q000502:physiology; D007305:Insecticide Resistance / Q000235:genetics / Q000502:physiology*; D007814:Larva / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D008969:Molecular Sequence Data; D009036:Moths / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism / Q000502:physiology*; D010572:Pest Control, Biological; D017386:Sequence Homology, Amino Acid
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins; D006460:Hemolysin Proteins; D019476:Insect Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis; C041137:storage proteins, Insecta