Sequence, localization and characteristics of the replicator region of the symbiotic plasmid of Rhizobium etli

• Published in: Microbiology (Society for General Microbiology) Vol. 143; no. 8; pp. 2825 - 2831
• Main Authors: Ramirez-Romero, Miguel A, Bustos, Patricia, Girard, Lourdes, Rodriguez, Oscar, Cevallos, Miguel A, Davila, Guillermo
• Format: Journal Article
• Language: English
• Published: Reading Soc General Microbiol 01-08-1997; Society for General Microbiology
• Subjects: Agrobacterium; Bacteriology; Biological and medical sciences; Cloning, Molecular; DNA Replication; Fundamental and applied biological sciences. Psychology; Gene Dosage; Gene Transfer Techniques; Genetics; Microbiology; Molecular Sequence Data; Plasmids - genetics; Restriction Mapping; Rhizobium - genetics; Rhizobium etli; Rhizobium leguminosarum; Sequence Analysis, DNA; Species Specificity; Symbiosis - genetics; Incompatibility; Plasmid; Site specificity; Symbiosis; Nucleotide sequence; Bacteria; Replication; Rhizobiaceae
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/00221287-143-8-2825

Departamento de Genética Molecular, Centro de Investigación sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Apartado Postal 565-A, Cuernavaca, Morelos, Mexico
Departamento de Ecología Molecular, Centro de Investigación sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Apartado Postal 565-A, Cuernavaca, Morelos, Mexico
1 Author for correspondence: Guillermo Dávila. Tel: [phone]. Fax: [phone]. e-mail: [e-mail]
ABSTRACT
Summary: The replicator region of the symbiotic plasmid of Rhizobium etli CFN42 was cloned and sequenced. A plasmid derivative (pH3) harbouring a 5.6 kb Hin dIII fragment from the symbiotic plasmid was found to be capable of independent replication and eliminated the symbiotic plasmid when introduced into a R. etli CFNX101 strain ( a recA derivative). The stability and the copy number of pH3 were the same as that of the symbiotic plasmid, indicating that the information required for stable replication and incompatibility resides in the 5.6 kb Hin dIII fragment. The sequence analysis of this fragment showed the presence of three ORFs similar in sequence and organization to repA, repB and repC described for the replicator regions of the Agrobacterium plasmids pTiB6S3 and pRiA4b and for the R. leguminosarum cryptic plasmid pRL8JI. Hybridization studies showed that p42d-like replicator sequences are found in the symbiotic plasmids of other R. etli strains and in a ‘cryptic’ plasmid of R. tropici.
Keywords: symbiotic plasmid, plasmid replication, Rhizobium etli
Present address: Departamento de Immunología, Instituto de Investi-gaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, D.F., Mexico.