Conjugative transfer of p42a from rhizobium etli CFN42, which is required for mobilization of the symbiotic plasmid, is regulated by quorum sensing.

ABSTRACT: Rhizobium etli CFN42 contains six plasmids. Only one of them, p42a, is self-conjugative at high frequency. This plasmid is strictly required for mobilization of the symbiotic plasmid (pSym). To study the transfer mechanism of p42a, a self-transmissible cosmid clone containing its transfer region was isolated. Its sequence showed that most of the tra genes are highly similar to genes of Agrobacterium tumefaciens pTiC58 and other related plasmids. Four putative regulatory genes were identified; three of these (traI, traR, and cinR) belong to the LuxR-LuxI family. Mutagenesis of these genes confirmed their requirement for p42a transfer. We found that the conjugative transfer of p42a is dependent on quorum sensing, and consequently pSym transfer also was found to be similarly regulated, establ

SUBMITTER: Tun-Garrido C 

PROVIDER: S-EPMC148057 | biostudies-literature | 2003 Mar

REPOSITORIES: biostudies-literature