title: Different Ancestries of R Tailocins in Rhizospheric Pseudomonas Isolates.
abstract: Bacterial genomes accommodate a variety of mobile genetic elements, including bacteriophage-related clusters that encode phage tail-like protein complexes playing a role in interactions with eukaryotic or prokaryotic cells. Such tailocins are unable to replicate inside target cells due to the lack of a phage head with associated DNA. A subset of tailocins mediate antagonistic activities with bacteriocin-like specificity. Functional characterization of bactericidal tailocins of two Pseudomonas putida rhizosphere isolates revealed not only extensive similarity with the tail assembly module of the Pseudomonas aeruginosa R-type pyocins but also differences in genomic integration site, regulatory genes, and lytic release modules. Conversely, these three features are quite similar between strains of the P. putida and Pseudomonas fluorescens clades, although phylogenetic analysis of tail genes suggests them to have evolved separately. Unlike P. aeruginosa R pyocin elements, the tailocin gene clusters of other pseudomonads frequently carry cargo genes, including bacteriocins. Compared with P. aeruginosa, the tailocin tail fiber sequences that act as specificity determinants have diverged much more extensively among the other pseudomonad species, mostly isolates from soil and plant environments. Activity of the P. putida antibacterial particles requires a functional lipopolysaccharide layer on target cells, but contrary to R pyocins from P. aeruginosa, strain susceptibilities surpass species boundaries.
authors.affiliation: Centre of Microbial and Plant Genetics (CMPG), University of Leuven, Heverlee, Belgium maarten.ghequire@biw.kuleuven.be.
authors.forename: Maarten G K
authors.initials: MG
authors.lastname: Ghequire
authors.affiliation: Group of Morphology, Biomedical Research Institute (BIOMED), Hasselt University, Diepenbeek, Leuven, Belgium.
authors.forename: Yörg
authors.initials: Y
authors.lastname: Dillen
authors.affiliation: Group of Morphology, Biomedical Research Institute (BIOMED), Hasselt University, Diepenbeek, Leuven, Belgium.
authors.forename: Ivo
authors.initials: I
authors.lastname: Lambrichts
authors.affiliation: Laboratory of Molecular Immunology, Department of Microbiology and Immunology, Rega Institute, University of Leuven, Belgium.
authors.forename: Paul
authors.initials: P
authors.lastname: Proost
authors.affiliation: Proteomics and Microbiology Laboratory, Research Institute for Biosciences, University of Mons, Mons, Belgium.
authors.forename: Ruddy
authors.initials: R
authors.lastname: Wattiez
authors.affiliation: Centre of Microbial and Plant Genetics (CMPG), University of Leuven, Heverlee, Belgium.
authors.forename: René
authors.initials: R
authors.lastname: De Mot
mesh_terms: D001430:Bacteriocins / Q000235:genetics / Q000378:metabolism*; D016680:Genome, Bacterial; D020071:Interspersed Repetitive Sequences; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D005810:Multigene Family; D028521:Musa / Q000382:microbiology; D009154:Mutation; D012275:Oryza / Q000382:microbiology; D010802:Phylogeny; D017105:Pseudomonas Phages / Q000235:genetics / Q000378:metabolism; D016958:Pseudomonas putida / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism* / Q000821:virology; D011709:Pyocins / Q000378:metabolism; D020539:Sequence Analysis, Protein; D016622:Silver Staining / Q000379:methods
chemical_list: D001430:Bacteriocins; D011709:Pyocins
keywords: antibacterial; bacteriocin; phage tail; pyocin