A comparison of the refractile bodies (R-bodies) of certain bacteria—III. Nucleotide sequence homologies and R-body function

Pseudomonas aeruginosa PA14 produces R-bodies, extendable protein polymers with roles in host colonization and virulence

R-bodies are long, extendable protein polymers formed in the cytoplasm of some bacteria; they are best known for their role in killing of paramecia by bacterial endosymbionts. Pseudomonas aeruginosa PA14, an opportunistic pathogen of diverse hosts, contains genes (referred to as the reb cluster) with potential to confer production of R-bodies and that have been implicated in virulence. Here, we show that products of the PA14 reb cluster associate with R-bodies and control stochastic expression of R-body structural genes. PA14 expresses reb genes during colonization of plant and nematode hosts, and R-body production is required for full virulence in nematodes. Analyses of nematode ribosome content and immune response indicate that P. aeruginosa R-bodies act via a mechanism involving ribosome cleavage and translational inhibition. Our observations provide insight into the biology of R-body production and its consequences during P. aeruginosa infection.

R-bodies are long, extendable protein polymers formed in the cytoplasm of some bacteria. Here, Wang et al. show that Pseudomonas aeruginosa produces R-bodies during colonization of plant and nematode hosts, and R-bodies induce ribosome cleavage and translational inhibition in nematodes.

R-bodies in Pseudomonas aeruginosa strain 44T1

For the first time R-bodies are described in a new strain 44T1 of Pseudomonas aeruginosa. Its size was measured as being 0.22 to 0.37 microns of width per 0.27 to 0.41 microns of length and 5 to 9 spiral turns about 16 nm. These structures are similar to previously observed in bacteria and are related with physiological state of bacteria in minimal conditions of growth.