Characterization of Pseudomonas fluorescens SF39a mutants affected in bacteriocin production

AGUSTINA GODINO; ANALÍA PRÍNCIPE; PAULA CORDERO; VIRGINIA RIGO; EDGARDO JOFRÉ; GLADYS MORI; SONIA FISCHER

Mendoza

Congreso; XLVII reunión anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2012

The objective of the present study was to identify genes involved in the biosynthesis or regulation of a bacteriocin produced by native strain Pseudomonas fluorescens SF39a. Random transposon mutagenesis of strain SF39a was carried out through the use of mini-Tn5Km1. Km-resistant clones were selected and screened for bacteriocin production. To identify the gene interrupted by the insertion of the transposon, flanking DNA region was cloned and sequenced in the mutants. Three transconjugants affected in the bacteriocin production were found: mutants 451 and 495 showed a decreased bacteriocin production while mutant 375 presented an enhanced bacteriocin production. The opposite phenotypes observed in clone 451 and 375 resulted from inactivation of the ptsP gene and cbrA gene, respectively. The former encodes a phosphoenolpyruvate protein and the latter encodes a sensor/histidine kinase of the two-component system CbrA/B. Both genes, ptsP and cbrA, play an important role in various virulence-related processes, such as mobility, biofilm formation and siderophore production. While, in the mutant 495 the transposon was inserted into a gene encoding a putative exported protein. These results provide new information about a possible regulation and export mechanism in the bacteriocins produced by plant-associated Pseudomonas.