title: Histopathological effects and determination of the putative receptor of Bacillus thuringiensis Cry1Da toxin in Spodoptera littoralis midgut.
abstract: Bacillus thuringiensis subsp. aizawai strain HD133, known by its effectiveness against Spodoptera species, produces many insecticidal proteins including Cry1Ab, Cry1Ca and Cry1Da. In the present study, the insecticidal activity of Cry1Da against Spodoptera littoralis was investigated. It showed toxicity with an LC(50) of 224.4 ng/cm(2) with 95% confidence limits of (178.61-270.19) and an LC(90) of 467.77 ng/cm(2) with 95% confidence limits of (392.89-542.65). The midgut histopathology of Cry1Da fed larvae showed vesicle formation in the apical region, vacuolization and destruction of epithelial cells. Biotinylated-activated Cry1Da toxin bound protein of about 65 kDa on blots of S. littoralis brush border membrane preparations. This putative receptor differs in molecular size from those recognized by Cry1C and Vip3A which are active against this polyphagous insect. This difference in midgut receptors strongly supports the use of Cry1Da as insecticidal agent, particularly in case of Cry and/or Vip-resistance management.
authors.affiliation: Biopesticides Team (LPAP), Centre of Biotechnology of Sfax, University of Sfax, P.O. Box 1177, 3018 Sfax, Tunisia.
authors.forename: Dalel
authors.initials: D
authors.lastname: BenFarhat-Touzri
authors.forename: Marwa
authors.initials: M
authors.lastname: Saadaoui
authors.forename: Lobna
authors.initials: L
authors.lastname: Abdelkefi-Mesrati
authors.forename: Imen
authors.initials: I
authors.lastname: Saadaoui
authors.forename: Hichem
authors.initials: H
authors.lastname: Azzouz
authors.forename: Slim
authors.initials: S
authors.lastname: Tounsi
mesh_terms: D000818:Animals; D001413:Bacillus thuringiensis / Q000378:metabolism* / Q000472:pathogenicity; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000633:toxicity*; D004731:Endotoxins / Q000633:toxicity*; D006460:Hemolysin Proteins / Q000633:toxicity*; D054884:Host-Pathogen Interactions; D019476:Insect Proteins / Q000378:metabolism*; D007306:Insecticides / Q000633:toxicity*; D007413:Intestinal Mucosa / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D007814:Larva / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D010572:Pest Control, Biological; D011956:Receptors, Cell Surface / Q000378:metabolism*; D018411:Spodoptera / Q000187:drug effects*
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; C095416:Cry toxin receptors; D004731:Endotoxins; D006460:Hemolysin Proteins; D019476:Insect Proteins; D007306:Insecticides; D011956:Receptors, Cell Surface; C030956:insecticidal crystal protein, Bacillus Thuringiensis