Assignment of biological functions to specific plasmids in a local isolate of Rhizobium cicer

Yıldız E., Ozcengız G., Icgen B., Alaeddınoglu N.

FOLIA MICROBIOLOGICA, vol.44, pp.55-58, 1999 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 44
  • Publication Date: 1999
  • Doi Number: 10.1007/bf02816222
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.55-58
  • Middle East Technical University Affiliated: Yes


The genetic basis of symbiosis, mucoid structure and melanin biosynthesis in a local isolate of Rhizobium cicer was investigated. The strain was avery effective symbiont and produced substantial amounts of exopolysaccharides and melanin. It harbored three high-molar-mass plasmids of 55, 80 and 130 kb, respectively. Thirty-one melanin production-negative (Mep(-)) derivatives were obtained through plasmid curing. The plasmid patterns of cured derivatives indicated that the loss of 55 and/or 80 kb plasmids was sufficient for obtaining Mep- phenotype. The specific involvement of 55-kb plasmid in melanin production was confirmed upon re-introduction of this plasmid into one of the Mep- derivatives. Further investigation also indicated that the 130-kb plasmid might be necessary for both mucoidal appearance and symbiotic functions.