title: Tn5-mediated integration of the delta-endotoxin gene from Bacillus thuringiensis into the chromosome of root-colonizing pseudomonads.
abstract: Gene replacement mediated by Tn5 sequences was used to integrate the Bacillus thuringiensis subsp. kurstaki HD-1 delta-endotoxin gene (tox) into the chromosome of two corn root-colonizing strains of Pseudomonas fluorescens. A Tn5 transposase deletion element containing the tox gene (delta Tn5-tox) was substituted for a Tn5 element previously present in the P. fluorescens chromosome. Two classes of delta Tn5-tox elements were made. The first class encodes kanamycin resistance in addition to the Tox protein, whereas the second class encodes only the Tox protein. Both classes of delta Tn5-tox elements can no longer transpose, owing to a 324-base-pair deletion in the transposase gene of IS50R, minimizing the potential for horizontal gene transfer of the tox gene to other bacterial species. A frameshift mutation in the transposase gene of IS50L was also constructed to eliminate the possibility of suppression or of a spontaneous reversion at the ochre termination codon that would create an active transposase. Expression of the Tox protein in P. fluorescens strains 112-12 and Ps3732-3-7 was demonstrated by an immunological assay (Western blot) and toxicity against larvae of the tobacco hornworm (Manduca sexta).
mesh_terms: D001413:Bacillus thuringiensis / Q000235:genetics*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D002876:Chromosomes, Bacterial; D004251:DNA Transposable Elements; D004274:DNA, Recombinant; D004731:Endotoxins / Q000096:biosynthesis / Q000235:genetics*; D005798:Genes, Bacterial; D006460:Hemolysin Proteins; D009154:Mutation; D009693:Nucleic Acid Hybridization; D009713:Nucleotidyltransferases / Q000235:genetics; D011551:Pseudomonas fluorescens / Q000235:genetics* / Q000378:metabolism; D019895:Transposases
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004251:DNA Transposable Elements; D004274:DNA, Recombinant; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis; D009713:Nucleotidyltransferases; D019895:Transposases