Phage tail-like bacteriocins: a new strategy for the biocontrol of phytopatho¬genic bacteria

FISCHER, S; FERNANDEZ, M; PRINCIPE, A

Tucuman

Congreso; XII Congreso Argentino de Microbiología General (SAMIGE); 2017

SAMIGE

Phage tail-like bacteriocins, called tailocins, represent a class of protein complexes synthesized by different bacterial species. The tailocins most known are R-type and F-type pyocins from Pseudomonas aeruginosa. In the last years, R-type pyocins have attracted attention as a strategy to replace antibiotics.Analysis of Pseudomonas spp. genomes showed that tailocins are also abundant in species other than P. aeruginosa. In our lab, we characterized the first tailocin in Pseudomonas fluorescens (strain SF4c).Phage tail-like structures were observed using Transmission Electron Microscopy (TEM) and AtomicForce Microscopy (AFM). These tailocins have antimicrobial activity against phytopathogenic bacteria, such as Xanthomonas axonopodis pv. vesicatoria, the causal agent of bacterial spot on tomato. An analysis through AFM demonstrated that bacteriocins adhere and cause damage to the cell envelope of X. axonopodis pv. vesicatoria Xcv Bv5–4a. This results in a rapid leakage of intracellular materials, with the subsequent decrease of cell volume. Under greenhouse conditions, the foliar application of tailocins significantly reduced of symptoms of bacterial leaf spot on tomato plants. Moreover, the bacteriocins were also effective in decreasing the severity of disease in fruit. Therefore, SF4c tailocins represent an alternative to antibiotics for their application in the biocontrol of bacterial diseases.