title: Sequence analysis of the 181-kb accessory plasmid pSmeSM11b, isolated from a dominant Sinorhizobium meliloti strain identified during a long-term field release experiment.
abstract: The 181 251 bp accessory plasmid pSmeSM11b of Sinorhizobium meliloti strain SM11, belonging to a dominant indigenous S. meliloti subpopulation identified during a long-term field release experiment, was sequenced. This plasmid has 166 coding sequences (CDSs), 42% of which encode proteins with homology to proteins of known function. Plasmid pSmeSM11b is a member of the repABC replicon family and contains a large gene region coding for a conjugation system similar to that of other self-transmissible plasmids in Rhizobium and Agrobacterium. Another pSmeSM11b gene region, possibly involved in sugar metabolism and polysaccharide catabolism, resembled a region of S. meliloti 1021 megaplasmid pSymB and in the genome of Sinorhizobium medicae WSM419. Another module of plasmid pSmeSM11b encodes proteins similar to those of the nitrogen-fixing actinomycete Frankia CcI3, and which are likely to be involved in the synthesis of a secondary metabolite. Several ORFs of pSmeSM11b were predicted to play a role in nonribosomal peptide synthesis. Plasmid pSmeSM11b has many mobile genetic elements, which contribute to the mosaic composition of the plasmid.
authors.affiliation: Lehrstuhl für Genetik, Fakultät für Biologie, Universität Bielefeld, Postfach 100131, D-33501 Bielefeld, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Stiens
authors.forename: Susanne
authors.initials: S
authors.lastname: Schneiker
authors.forename: Alfred
authors.initials: A
authors.lastname: Pühler
authors.forename: Andreas
authors.initials: A
authors.lastname: Schlüter
mesh_terms: D003227:Conjugation, Genetic; D023061:Gene Order; D005798:Genes, Bacterial; D000455:Medicago sativa / Q000382:microbiology; D008969:Molecular Sequence Data; D018517:Plant Roots / Q000382:microbiology; D010957:Plasmids / Q000235:genetics*; D012093:Replicon / Q000235:genetics; D017422:Sequence Analysis, DNA; D016962:Sinorhizobium meliloti / Q000235:genetics* / Q000254:growth & development