A site-specific recombinase (RinQ) is required to exert incompatibility towards the symbiotic plasmid of Rhizobium etli

Abstract

The replication/partition region of the symbiotic plasmid p42d of Rhizobium etli CE3 is characterized by the presence of the repABC operon. A recombinant plasmid containing this region is able to replicate in a R. etli derivative cured from p42d, with the same stability and copy number shown by the parental plasmid. However, when this construct is introduced into the wild-type strain, instead of exerting incompatibility against the p42d, it forms a stable cointegrate with it. In this paper, we show that a site-specific resolvase, and its action sites are essential factors to displace the symbiotic p42d. We propose a model for this novel incompatibility mechanism.