title: Evidence of oral toxicity of Photorhabdus temperata strain K122 against Prays oleae and its improvement by heterologous expression of Bacillus thuringiensis cry1Aa and cry1Ia genes.
abstract: Photorhabdus temperata strain K122 exhibited oral toxicity against Prays oleae with an LC50 of 58.1 x 10(6) cells ml(-1). Recombinant P. temperata strains expressing the cry1Aa and/or cry1Ia genes of Bacillus thuringiensis have been constructed. The two cry genes, encoding delta-endotoxins, were placed under the control of the lac promoter and IPTG dependent expression in P. temperata was demonstrated. The presence of the cry genes in K122 resulted in a clear improvement of oral toxicity. This improvement was of 6.2-, 6.6-, and 14.6-fold for the strains K122(pBCcry1Aa), K122(pBScry1Ia), and K122(pBCcry1Aa + pBScry1Ia), respectively. Furthermore, determination of the Synergistic Factor between Cry1Aa and Cry1Ia showed that they act synergistically. This work demonstrates that the heterologous expression of B. thuringiensis cry genes in P. temperata can be used to improve and broaden its host range for insect control.
authors.affiliation: Laboratory of Biopesticides, Centre of Biotechnology of Sfax, P.O. Box K, 3038. Sfax, Tunisia.
authors.forename: Slim
authors.initials: S
authors.lastname: Tounsi
authors.forename: Ammar Ebn
authors.initials: AE
authors.lastname: Aoun
authors.forename: Mark
authors.initials: M
authors.lastname: Blight
authors.forename: Ahmed
authors.initials: A
authors.lastname: Rebaî
authors.forename: Samir
authors.initials: S
authors.lastname: Jaoua
mesh_terms: D000818:Animals; D001413:Bacillus thuringiensis / Q000235:genetics*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000235:genetics* / Q000633:toxicity; D001427:Bacterial Toxins / Q000235:genetics* / Q000633:toxicity; D015153:Blotting, Western; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics; D004274:DNA, Recombinant; D004591:Electrophoresis, Polyacrylamide Gel; D004731:Endotoxins / Q000235:genetics* / Q000633:toxicity; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D006460:Hemolysin Proteins; D009036:Moths / Q000382:microbiology*; D010572:Pest Control, Biological; D020637:Photorhabdus / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology*; D011401:Promoter Regions, Genetic; D014169:Transformation, Bacterial
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004269:DNA, Bacterial; D004274:DNA, Recombinant; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis