|Di Lorenzo, Manuela - OREGON HEALTH & SCIENCES|
|Crosa, Jorge - OREGON HEALTH & SCIENCES|
Submitted to: American Society for Microbiology Meeting
Publication Type: Abstract Only
Publication Acceptance Date: May 18, 2003
Publication Date: May 18, 2003
Citation: Welch, T.J., Di Lorenzo, M., Crosa, J. 2003. Identification of a siderophore biosynthetic gene from the fish pathogen aeromonas salmonicida. 103d American Society for Microbiology Meeting. p.216. Technical Abstract: Aeromonas salmonicida is the causative agent of furunculosis, a septicemic disease of salmonid fish. While production of siderophore activity has been demonstrated in pathogenic strains of A. salmonicida, this activity has not yet been characterized. To identify the genes involved in siderophore synthesis and utilization in A. salmonicida, mutants were generated using the mini-transposon mini-Tn5K, and screened for defects in the production of siderophore activity on chromazurol S agar (CAS agar). Using this approach several mutants with altered siderophore production phenotypes were identified. One such mutant, designated AStn-11, grew poorly and overproduced siderophore activity when grown on CAS agar, this phenotype is likely due to the insertion occurring in a transport gene. By transposon-directed cloning of the insertion in AStn-11, a cluster of genes encoding putative siderophore transport and biosynthetic proteins was identified. One of the genes in the cluster encodes a large nonribosomal peptide synthetase, salF, similar to the enzymes involved in the biosynthesis of a number of peptide-like siderophores. An insertion mutation in salF resulted in the reduction, but not abolishment, of siderophore production, suggesting the existence of multiple siderophores in this strain. By thin layer chromatography we confirmed that multiple siderophores are produced by this strain and showed that the salF gene is essential for the production of one of the siderophores produced.