A new method for the physical and genetic mapping of large plasmids: application to the localisation of the virulence determinants on the 90 kb plasmid of Salmonella typhimurium.

A new method based on transposon-promoted deletions was used to generate a set of deletions in the 90 kb virulence plasmid of Salmonella typhimurium. The analysis of 16 deletion mutants allowed: (1) construction of the restriction map of the plasmid for HindIII, BamHI and BglII; (2) localisation of the plasmid region involved in virulence; (3) identification of two functional replicons on the plasmid.