THE prtRGENE INDIRECTLY ACTIVATES THE BACTERIOCIN PRODUCTION INPseudomonas fluorescens SF4C

MARICRUZ FERNANDEZ; AGUSTINA GODINO; ANALÍA PRÍNCIPE; SONIA FISCHER

Córdoba

Congreso; LII Reunión Anual-Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2016

Bacteriocins are proteins produced by bacteria that can kill closely related species.P. fluorescensSF4c is a plant-growth promoting bacterium that synthesizes bacteriocins (phage-like pyocins), which inhibit the growth of phytopathogenic strains belonging to the generaPseudomonasandXanthomonas. The complete pyocin cluster was identified in the genome of the strain SF4c, finding structural genes of R and F-type pyocins, as well as, regulatory and lytic genes. TheprtRgene is one of these putative regulatory genes and its ortholog inP. aeruginosaencodes a repressor protein. The aim of this work was to study the function ofprtRin strain SF4c. The amino acid sequence of PrtR from strain SF4c is characteristic of repressor proteins. PrtR has two Pfam domains: a helix-turn-helix DNA binding domain of transcription regulators in the N-terminal end and a peptidase-S24 domain with a C1 repressor in the C-terminal end. A mutantprtRwas constructed by gene replacement via homologous recombination and calledP. fluorescensSF4c-prtR. Surprisingly, this mutant showed a deficiency in bacteriocin production compared with the wild-type strain. These results indicate thatprtRactivates the pyocin production in strain SF4c, probably, by indirect modulation. PrtR could repress the activity of a second repressor, still unknown, leading to activation of pyocin synthesis as final result