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Can J Microbiol

Title:		"Evidence and characterization of a gene cluster required for the production of viscosin, a lipopeptide biosurfactant, by a strain of Pseudomonas fluorescens"
Author(s):		Braun PG; Hildebrand PD; Ells TC; Kobayashi DY;
Address:		"Atlantic Food and Horticulture Research Centre, Agriculture and Agri-Food Canada, Kentville, NS. braung@em.agr.ca"
Journal Title:		Can J Microbiol
Year:		2001
Volume:		47
Issue:		4
Page Number:		294 - 301
DOI:		10.1139/w01-017
ISSN/ISBN:		0008-4166 (Print) 0008-4166 (Linking)
Abstract:		"The genetic control of viscosin production was examined in a strain of Pseudomonas fluorescens (PfA7B) that causes broccoli head rot. Viscosin is a potent lipopeptide biosurfactant that enables the bacteria to come into intimate contact with the difficult-to-wet waxy heads of broccoli. Tn5 mutagenesis completely disrupted viscosin production as shown by HPLC analysis of the mutagenized cell lysates. The Vis- mutants retained their pectolytic capability and were able to decay potato slices. On broccoli, however, the Vis- mutants caused decay of wounded florets, but the decay failed to spread to adjacent nonwounded florets as had occurred with the wild-type PfA7B. Triparental matings of the Vis- mutants with their corresponding wild-type clones and the helper Escherichia coli HB101 carrying the mobilization plasmid pPK2013 resulted in three stable viscosin-producing transconjugants that caused typical decay of broccoli tissue. Linkage maps of clones and protein profiles showed that a 25-kb chromosomal DNA region of PfA7B affected the production of three high molecular mass proteins required for viscosin synthesis. These proteins, approximately 218, 215, and 137 kDa in size, likely compose a synthetase complex that assembles the nine amino acid peptide of viscosin and subsequently attaches this to the hydrophobic fatty acid component of the molecule. A probe made from this DNA region hybridized with DNA fragments of other phytopathogenic pseudomonads to varying degrees"
Keywords:		"Anti-Bacterial Agents/biosynthesis Brassica/microbiology Cosmids/genetics DNA, Bacterial/chemistry/isolation & purification Electrophoresis, Polyacrylamide Gel Escherichia coli/genetics Gene Library Genetic Complementation Test Genetic Linkage Ligases/met;"
Notes:		"MedlineBraun, P G Hildebrand, P D Ells, T C Kobayashi, D Y eng Canada 2001/05/19 Can J Microbiol. 2001 Apr; 47(4):294-301. doi: 10.1139/w01-017"