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 体是在某些细菌的细胞质中形成的长的、可延伸的蛋白质聚合物；它们最著名的作用是通过细菌内共生体杀死草履虫。铜绿假单胞菌PA14 是一种不同宿主的机会性病原体，包含具有产生 R 体的潜力并且与毒力有关的基因（称为reb簇）。在这里，我们展示了 PA14 reb簇的产物与 R 体相关联并控制 R 体结构基因的随机表达。PA14在植物和线虫宿主定殖过程中表达reb基因，线虫完全毒力需要 R 体产生。线虫核糖体含量和免疫反应的分析表明，铜绿假单胞菌R 体通过涉及核糖体裂解和翻译抑制的机制起作用。我们的观察提供了对铜绿假单胞菌感染期间 R 体产生的生物学及其后果的深入了解。