Symbiotic loci of Rhizobium meliloti identified by random TnphoA mutagenesis
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چکیده
منابع مشابه
Directed transposon Tn5 mutagenesis and complementation analysis of Rhizobium meliloti symbiotic nitrogen fixation genes.
An 18 kb region adjacent to and surrounding the genes for nitrogenase (nif) was cloned from the genome of the symbiotic nitrogen-fixing species Rhizobium meliloti. A total of 31 Tn5 insertions in the nif region were constructed and assayed for their effect on symbiotic nitrogen fixation (Fix phenotype). Fix- insertions were found in two clusters, one 6.3 kb region not containing essential symbi...
متن کاملPhysical and genetic characterization of symbiotic and auxotrophic mutants of Rhizobium meliloti induced by transposon Tn5 mutagenesis.
We have physically and genetically characterized 20 symbiotic and 20 auxotrophic mutants of Rhizobium meliloti, the nitrogen-fixing symbiont of alfalfa (Medicago sativa), isolated by transposon Tn5 mutagenesis. A "suicide plasmid" mutagenesis procedure was used to generate TN-5-induced mutants, and both auxotrophic and symbiotic mutants were found at a frequency of 0.3% among strains containing...
متن کاملThe lipo-oligosaccharidic symbiotic signals of Rhizobium meliloti.
288 time to identify the carbohydrate-bearing structures. Recent examples of glycoproteins originally detected with lectins that have now been identified are desmosomal glycoproteins [ 151 and integrins [ 161. Changes in the carbohydrate moieties of adhesion molecules can alter their function [ 17-19] and thus the lectin patterns may turn out to provide new insights into the changes in the adhe...
متن کاملRhizobium meliloti exopolysaccharides: genetic analyses and symbiotic importance.
Genetic experiments have indicated that succinoglycan (EPS I), the acidic Calcofluor-binding exopolysaccharide, of the nitrogen-fixing bacterium Rhizobium meliloti strain Rm1021 is required for nodule invasion and possibly for later events in nodule development on alfalfa and other hosts. Fourteen exo loci on the second megaplasmid have been identified that are required for, or affect, the synt...
متن کاملA phosphate transport system is required for symbiotic nitrogen fixation by Rhizobium meliloti.
The bacterium Rhizobium meliloti forms N2-fixing root nodules on alfalfa plants. The ndvF locus, located on the 1,700-kb pEXO megaplasmid of R. meliloti, is required for nodule invasion and N2 fixation. Here we report that ndvF contains four genes, phoCDET, which encode an ABC-type transport system for the uptake of Pi into the bacteria. The PhoC and PhoD proteins are homologous to the Escheric...
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ژورنال
عنوان ژورنال: Journal of Bacteriology
سال: 1988
ISSN: 0021-9193,1098-5530
DOI: 10.1128/jb.170.9.4257-4265.1988