Tailocins in action: defence strategie of rhizospheric Pseudomonas

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

La Plata

Workshop; Imaging Techniques for Biotechnology and Biomedical Applications -Workshop-; 2016

Bacteriocins are protein produced by bacteria that can kill closelyrelated species to the producer. P. aeruginosa synthetizes three typesof pyocins that differ in their morphology and killing mode: R, F(phage tail-like bacteriocins) and S (soluble proteins) -type pyocins(Ghequire and De Mot, 2014). P. fluorescens SF4c is a plant-growthpromoting bacterium that produces phage-like pyocins (tailocins),which inhibit the growth of the phytopathogenic strain Xanthomonasaxonopodis pv vesicatoria Xcv Bv5-4a (Fischer et al., 2012). Theaim of this work was to elucidate the action mode of the tailocinssecreted by the strain SF4c. The structure of the tailocin wasvisualized by transmission electron microscopy (TEM) and atomicforce microscopy (AFM). Action mechanism of the tailocins on thestrains X. axonopodis pv vesicatoria Xcv Bv5-4a and P. protegensCHA0 was studied by atomic force microscopy (AFM). The pyocinspresented a structure similar to the bacteriophage tails and they wereattached to the surface cell Xcv Bv5-4a to exert their antimicrobialaction. The tailocins action was evidenced in the AFM images as adecrease in the cell height of strain Xcv Bv5-4a. These results suggestthat the action mechanism ofthese pyocins involve thedamage of the membrane ofsusceptive cells, probably byformation of pores and then, aloss of intracellular material.In contrast, the tailocins havenot effect on strain CHA0. Thecharacterization of this class ofantimicrobial compounds isrelevant for their potentialapplication as biocontrol agent