Two opines control conjugal transfer of an Agrobacterium plasmid by regulating expression of separate copies of the quorum-sensing activator gene traR.

ABSTRACT: Conjugal transfer of Ti plasmids from Agrobacterium spp. is controlled by a hierarchical regulatory system designed to sense two environmental cues. One signal, a subset of the opines produced by crown gall tumors initiated on plants by the pathogen, serves to induce production of the second, an acyl-homoserine lactone quorum-sensing signal, the quormone, produced by the bacterium itself. This second signal activates TraR, and this transcriptional activator induces expression of the tra regulon. Opines control transfer because the traR gene is a member of an operon the expression of which is regulated by the conjugal opine. Among the Ti plasmid systems studied to date, only one of the two or more opine families produced by the associated tumor induces transfer. However, two chemically diss

SUBMITTER: Oger P 

PROVIDER: S-EPMC134798 | biostudies-literature | 2002 Feb

REPOSITORIES: biostudies-literature