Transcriptomic Analysis Reveals the Dependency of Pseudomonas aeruginosa Genes for Double-Stranded RNA Bacteriophage phiYY Infection Cycle

Bacteriophage phiYY is currently the only double-stranded RNA (dsRNA) phage that infects Pseudomonas aeruginosa and is a potential candidate for phage therapy. Here we applied RNA-seq to investigate the lytic cycle of phiYY infecting P. aeruginosa strain PAO1r. About 12.45% (651/5,229) of the host genes were determined to be differentially expressed genes. Moreover, oxidative stress response genes katB and ahpB are upregulated 64- to 128-fold after phage infection, and the single deletion of each gene blocked phiYY infection, indicating that phiYY is extremely sensitive to oxidative stress. On the contrary, another upregulated gene PA0800 might constrain phage infection, because the deletion of PA0800 resulted in a 3.5-fold increase of the efficiency of plating. Our study highlights a complicated dsRNA phage-phage global interaction and raises new questions toward the host defense mechanisms against dsRNA phage and dsRNA phage-encoded hijacking mechanisms.