Fig. 1. Characterization of select tailocin samples.

Tailocins produced by our isolates Pse11, Pse04, Pse06, and Pse05 were characterized further in this study. A Tailocin biosynthetic gene clusters. Genes are colored by the presence of key words in their PHASTER [70] predicted annotations. Genes in the same group of orthologs (“orthogroup,” see Methods, Supplementary Table S3) are joined by a block of color. The products of starred (*) genes are observed in our partially purified tailocin samples using MudPIT proteomics (Methods, Supplementary Table S4). Additional data on these clusters can be found in Supplementary Table S2. B Phylogeny of R-type tailocins by tail tube protein sequence. These are delineated by clade as per their relationship to the following tailocins: P. aeruginosa PAO1 R2 pyocin (Rp1), P. putida BW11M1 R-type tailocin (Rp2), P. fluorescens SF4c R-type tailocin 1 (Rp3), and P. syringae B728a R-type tailocin (Rp4) [26]. C A schematic of tailocin–host interactions characterized in this work is presented (top). Characterization of five lethal tailocin interactions by TEM and by spotting fivefold dilution series of samples (bottom). Scale bar: 20 nm. Gray triangles illustrate the relative concentration of tailocins in the dilution series. Zones of inhibition formed by diluted samples are indicative of nonreplicative toxins, not phages. Spotting was done in triplicate and replicates gave identical data.