title: Megaplasmid pRme2011a of Sinorhizobium meliloti is not required for viability.
abstract: We report the curing of the 1,360-kb megaplasmid pRme2011a from Sinorhizobium meliloti strain Rm2011. With a positive selection strategy that utilized Tn5B12-S containing the sacB gene, we were able to cure this replicon by successive rounds of selecting for deletion formation in vivo. Subsequent Southern blot, Eckhardt gel, and pulsed-field gel electrophoresis analyses were consistent with the hypothesis that the resultant strain was indeed missing pRme2011a. The cured derivative grew as well as the wild-type strain in both complex and defined media but was unable to use a number of substrates as a sole source of carbon on defined media.
authors.affiliation: Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada.
authors.forename: I J
authors.initials: IJ
authors.lastname: Oresnik
authors.forename: S L
authors.initials: SL
authors.lastname: Liu
authors.forename: C K
authors.initials: CK
authors.lastname: Yost
authors.forename: M F
authors.initials: MF
authors.lastname: Hynes
mesh_terms: D015139:Blotting, Southern; D016521:Electrophoresis, Gel, Pulsed-Field; D017353:Gene Deletion; D005819:Genetic Markers; D010641:Phenotype; D010957:Plasmids / Q000235:genetics*; D016962:Sinorhizobium meliloti / Q000235:genetics* / Q000254:growth & development*
chemical_list: D005819:Genetic Markers