A cryptic plasmid of indigenous Rhizobium meliloti possesses reiterated nodC and nifE genes and undergoes DNA rearrangement
| Autor: | S. T. Whitwill, L. R. Barran, V. K. Rastogi, E. S. P. Bromfield |
|---|---|
| Rok vydání: | 1992 |
| Předmět: |
Genetics
chemistry.chemical_classification biology Strain (chemistry) Immunology Mutant food and beverages General Medicine Agrobacterium tumefaciens biochemical phenomena metabolism and nutrition biology.organism_classification Applied Microbiology and Biotechnology Microbiology Plasmid chemistry Cosmid bacteria Rhizobium Nucleotide Molecular Biology Gene |
| Zdroj: | Canadian Journal of Microbiology. 38:563-568 |
| ISSN: | 1480-3275 0008-4166 |
| DOI: | 10.1139/m92-092 |
| Popis: | Indigenous Rhizobium meliloti were previously characterized on the basis of plasmid profiles and phage sensitivity patterns (phage types). Rhizobium meliloti 1076, which contained two cryptic plasmids, was one of four isolates comprising phage type 23. In this study, the large cryptic plasmid pVS1(size >500 b) was transferred from isolate 1076 into the plasmid-free strain of Agrobacterium tumefaciens UBAPF1. This plasmid contained nucleotide sequences homologous to genes for nodulation (nodB, nodC) and nitrogen fixation (nifH, nifD, nifK, nifE). Cosmid clones possessing the nod and nif homologous sequences, which had been selected from a genomic bank of A. tumefaciens UBAPF1 containing pVS1, complemented R. meliloti nodC and nifE mutants, respectively. These results demonstrate that the nodC and nifE homologous sequences are functionally expressed. Three of four isolates comprising phage type 23 possessed a megaplasmid band in agarose gels characteristic of R. meliloti, as well as two cryptic plasmids. The fourth isolate (No. 323) lacked the large cryptic plasmid corresponding to pVS1, but instead showed a band of lesser mobility than that of the megaplasmids. Nevertheless, its restricted genomic DNA retained the nodC and nifE hybridizing fragments characteristic of pVS1, indicating that the cryptic plasmid has undergone DNA rearrangement. Key words: Rhizobium, plasmid, reiteration, genes, rearrangement. |
| Databáze: | OpenAIRE |
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