title: Isolation and characterization of Tn5 insertion mutants of Pseudomonas syringae pv. syringae altered in the production of the peptide phytotoxin syringotoxin.
abstract: A syringotoxin-producing strain of Pseudomonas syringae pv. syringae (B457) was subjected to Tn5 mutagenesis by the transposon vector pSUP1011. Analyses of auxotrophs obtained suggested simple random insertions of Tn5. Syringotoxin-negative mutants arose at a frequency of about 0.28%. In a Southern blot analysis, the loss of toxin production was associated with Tn5 insertions into chromosomal EcoRI fragments of about 10.5, 17.8, and 19.3 kilobases. Data from a Southern blot analysis of SstI-digested DNA from these mutants suggest that the 10.5- and 17.8-kilobase EcoRI fragments may be adjacent to or near each other. Mutants that produced only 3 to 4% wild-type toxin levels also were identified.
mesh_terms: D001427:Bacterial Toxins / Q000096:biosynthesis*; D001483:Base Sequence; D004251:DNA Transposable Elements; D009154:Mutation; D010452:Peptide Biosynthesis; D010456:Peptides, Cyclic; D010957:Plasmids; D011549:Pseudomonas / Q000235:genetics* / Q000472:pathogenicity
chemical_list: D001427:Bacterial Toxins; D004251:DNA Transposable Elements; D010456:Peptides, Cyclic; C069036:syringotoxin B