Genetic and physical analyses of group E exo- mutants of Rhizobium meliloti
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چکیده
منابع مشابه
Characterization of polysaccharides of Rhizobium meliloti exo mutants that form ineffective nodules.
Mutants of Rhizobium meliloti SU47 with defects in the production of the Calcofluor-binding expolysaccharide succinoglycan failed to gain entry into alfalfa root nodules. In order to define better the polysaccharide phenotypes of these exo mutants, we analyzed the periplasmic oligosaccharide cyclic (1-2)-beta-D-glucan and lipopolysaccharide (LPS) in representative mutants. The exoC mutant lacke...
متن کاملAll nod genes of Rhizobium meliloti are involved in alfalfa nodulation by exo mutants.
Nodulation of alfalfa by exoB mutants of Rhizobium meliloti occurred without root hair curling or infection thread formation. nod exoB double mutants had the same nodulation deficiency as single nod mutants. Therefore, all the known nod genes are involved in nodule induction by exoB mutants, which apparently occurs via intercellular invasion.
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 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 کاملInterference between Rhizobium meliloti and Rhizobium trifolii nodulation genes: genetic basis of R. meliloti dominance.
Transfer of an IncP plasmid carrying the Rhizobium meliloti nodFE, nodG, and nodH genes to Rhizobium trifolii enabled R. trifolii to nodulate alfalfa (Medicago sativa), the normal host of R. meliloti. Using transposon Tn5-linked mutations and in vitro-constructed deletions of the R. meliloti nodFE, nodG, and nodH genes, we showed that R. meliloti nodH was required for R. trifolii to elicit both...
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ژورنال
عنوان ژورنال: Journal of Bacteriology
سال: 1988
ISSN: 0021-9193,1098-5530
DOI: 10.1128/jb.170.1.474-477.1988