We compared the nodulation competitiveness of three strains of Rhizobium leguminosarum by counting the number of nodules formed on faba bean plants after the application at sowing time of different concentrations of the strains to soils already containing Rhizobium strains of the same species. A relationship of type y = ax was found to exist between the ratio of the nodules formed by the applie...

Physiological responses to infection by strains of Rhizobium leguminosarum which differed in their capacity to reduce N(2) were determined in 26-day-old pea plants (Pisum sativum L. cv. Alaska) grown under uniform environmental conditions in the absence of combined N. The highest N(2) reduction rates, calculated from H(2) evolution and C(2)H(2)-dependent C(2)H(4) production measurements, were a...

Fourteen soil bacteriophages active against Rhizobium trifolii W19 have been studied which fall into four structural groups. Group 1 phages have contractile tails. Some particles show double base plates to which at least three spikes are attached, and fibers are attached to the base plates. Group 2 phages also have contractile tails. At least five spikes are attached to the base plate, and ther...

Of 18 Rhizobium trifolii strains tested, 12 showed a high frequency of loss of nodulation ability after incubation in cultures at elevated temperatures. A correlation between loss of nodulation ability and loss of a large plasmid was demonstrated for R. trifolii. In some nonnodulating (Nod-) mutants, deletions occurred instead of total elimination of the plasmid molecule. The maximum curing eff...

The major oligosaccharide from the core region of the lipopolysaccharide from R. trifolii ANU843 was isolated and its structure determined. It is a trisaccharide consisting of two galacturonic acid residues and one 3-deoxy-D-manno2octulosonic acid (KDO) residue. The two galacturonic acid residues are terminally linked alpha to the C-4 and C-7 atoms of KDO. This structure was determined through ...

B ernhard Epping, A lexander P. H ansen, Bahm an Djalali and Peter M artin Institut für Pflanzenernährung (330), Universität Hohenheim, Fruwirthstraße 20, D-70593 Stuttgart, Bundesrepublik Deutschland Z. Naturforsch. 49c, 343-351 (1994); received February 4, 1994 Phaseolus vulgaris L., Plant x Bacterium Interaction, Rhizobium leguminosarum bv. phaseoli, Rhizobium tropici, Symbiotic Effectivity ...

An interrelationship between introduced and indigenous rhizobia focused on their competitiveness in nodulation was evaluated in a soil pot experiment. Clover seeds were inoculated by six different gradual concentrations of inoculum of two effective Rhizobium leguminosarum bv. trifolii isolates (inoculation strains 1/2 and 14/2). At the beginning of flowering, clover plants were removed from the...

The Rhizobium leguminosarum biovar viciae nodulation protein NodO is partially homologous to haemolysin of Escherichia coli and, like haemolysin, is secreted into the growth medium. The NodO protein can be secreted by a strain of E. coli carrying the cloned nodO gene plus the haemolysin secretion genes hlyBD, in a process that also requires the outer membrane protein encoded by tolC. The relate...