Characterization of phage-like pyocins from Pseudomonas SF4C

MARICRUZ FERNANDEZ; AGUSTINA GODINO; GUSTAVO MORALES ; ANALÍA PRÍNCIPE; SONIA FISCHER

Mar del Plata

Congreso; LI reunión anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2015

Bacteriocins are protein produced by bacteria that can kill closely related species. P. fluorescens SF4c is a plantgrowthpromoting bacterium that synthesizes bacteriocins (phage-like pyocins), which inhibit the growth of thephytopathogenic strain Xanthomonas axonopodis pv vesicatoria Xcv Bv5-4a. The aim of this work was tocharacterize the pyocins secreted by the strain SF4c. The complete cluster of pyocins was identified in the genome ofthe strain SF4c, finding structural genes of the pyocins R and F, as well as, regulatory and lytic genes. The structureof the bacteriocin and its mechanism of action on the sensitive strain X. axonopodis pv vesicatoria Xcv Bv5-4a wasstudied by atomic force microscopy (AFM). The pyocins presented a structure similar to the bacteriophage tails andthey were attached to the surface of the cell to exert their antimicrobial action. The action of the pyocins on the cellwas evidenced by a diminution of their volume, observed as a decrease in the height of cell Xcv Bv5-4a in the AFMimage. These results suggest that the mechanism of action of these pyocins involve the damage of the membrane ofsusceptive cells, probably by formation of pores. The characterization of this class of antimicrobial compounds isrelevant because of their potential application as biocontrol agent.