The repAC replication system of the Rhizobium leguminosarum pRL7 plasmid is functional: Implications regarding the origin and evolution of repABC plasmids

► We evaluated the functionality of the repAC genes of Rhizobium leguminosarum pRL7. ► The repAC genes are organized in an operon. ► The repAC are capable of sustaining replication but in an unstable manner. ► RepA has a marginal role in the negative regulation of its own transcription. ► RepC is essential for replication, and the oriV resides within its coding region.