The adsorption of Pseudomonas aeruginosa bacteriophage φKMV is dependent on expression regulation of type IV pili genes

Pseudomonas aeruginosa bacteriophage phi KMV requires type IV pili for infection, as observed from the phenotypic characterization and phage adsorption assays on a phage infection-resistant host strain mutant. A cosmid clone library of the host (P. aeruginosa PAO1) genomic DNA was generated and used to select for a clone that was able to restore phi KMV infection in the resistant mutant. This complementing cosmid also re-established type IV pili-dependent twitching motility. The correlation between bacteriophage phi KMV infectivity and type IV pili, along with its associated twitching motility, was confirmed by the resistance of a P. aeruginosa PAO1 Delta pilA mutant to the phage. Subcloning of the complementing cosmid and further phage infection analysis and motility assays suggests that a common regulatory mechanism and/or interaction between the ponA and pilMNOPQ gene products are essential for bacteriophage phi KMV infectivity.