The Salmonella typbimurium RecJ function permits growth of P22 abc phage on recBCD⁺ hosts

We describe recJ mutants of Salmonella typhimurium. The recJ gene maps between sufD and serA (min 62) and is transcribed counterclockwise. Unlike recJ mutants of Escherichia coli, recJ strains of S. typhimurium are sensitive to irradiation with UV light. This sensitivity is equivalent to or greater that that displayed by recBCD mutant strains. The residual ability of phage P22 abc (anti-recBCD) mutants to form plaques on recBCD⁺ strains is eliminated in recJ hosts. Thus host RecJ function appears to substitute for the anti-RecBCD functions of phage P22 and may serve to limit RecBCD activity.