Live cell dynamics of production, explosive release and killing activity of phage tail-like weapons for Pseudomonas kin exclusion

Interference competition among bacteria requires a highly specialized, narrow-spectrum weaponry when targeting closely-related competitors while sparing individuals from the same clonal population. Here we investigated mechanisms by which environmentally important Pseudomonas bacteria with plant-beneficial activity perform kin interference competition. We show that killing between phylogenetically closely-related strains involves contractile phage tail-like devices called R-tailocins that puncture target cell membranes. Using live-cell imaging, we evidence that R-tailocins are produced at the cell center, transported to the cell poles and ejected by explosive cell lysis. This enables their dispersal over several tens of micrometers to reach targeted cells. We visualize R-tailocin-mediated competition dynamics between closely-related Pseudomonas strains at the single-cell level, both in non-induced condition and upon artificial induction. We document the fatal impact of cellular self-sacrifice coupled to deployment of phage tail-like weaponry in the microenvironment of kin bacterial competitors, emphasizing the necessity for microscale assessment of microbial competitions. Vacheron et al. visualize the dynamics of production, cellular transport and release of phage tail-like devices called R-tailocins by Pseudomonas bacteria and demonstrate their kin killing activity at single-cell level. The study offers insights into microbial competition mechanisms.

Automated summary

This study investigates the mechanisms by which environmentally important Pseudomonas bacteria perform kin interference competition through the use of R-tailocins. The findings demonstrate the deadly impact of cellular self-sacrifice coupled with deployment of phage tail-like weaponry on closely-related bacterial competitors, highlighting the importance of microscale assessment in microbial competitions.