13 research outputs found
Insertion sequence (IS) hybridization supports classification of Rhizobium meliloti by phage typing
Relative genetic structure of a population of Rhizobium meliloti isolated directly from soil and from nodules of alfalfa (Medicago sativa) and sweet clover (Melilotus alba)
Effectiveness of three inoculation methods for lucerne ( Medicago sativa
The efficacy of ALOSCA®, coated and peat seed inoculant treatments on the nodulation of lucerne sown in two soils in Canterbury, New Zealand was investigated. The commercial inoculant was Sinorhizobium meliloti strain RRI128. It was recovered from the nodules of lucerne plants grown from ALOSCA®, peat and coated seed at both sites. Coated seed had the highest nodule occupancy with 45% and 47% of nodules containing S. meliloti strain RRI128 at the Ashley Dene and Lincoln University field sites, respectively. ALOSCA® had only 9% and 16% of nodules from the Ashley Dene and Lincoln University field sites, respectively, containing S. meliloti strain RRI128. Naturalised Rhizobium strains were also recovered from the nodules of lucerne plants grown from ALOSCA®, coated and peat seed inoculant treatments. A single genotype (genotype A) of a Rhizobium sp. was recovered more frequently than the inoculated S. meliloti strain in the nodules of plants grown from peat treated seed at Lincoln University (30% vs 22%) and in the nodules of ALOSCA® treated seed at Ashley Dene (54% vs 9%). Bare seed was also nodulated by the Rhizobium sp. genotype A with 57% and 28% of nodules from plants grown from uninoculated seed at Ashley Dene and Lincoln University, respectively, containing this strain. This research shows delivery by an appropriate inoculation treatment is required to maximise occupancy by the commercial strain
Resuscitation of Viable But Not Culturable Sinorhizobium meliloti 41 pRP4-luc: Effects of Oxygen and Host Plant
Generation of Rhizobium strains with improved symbiotic properties by random DNA amplification (RDA)
Cross-species transferability of EST-SSR markers developed from the transcriptome of Melilotus and their application to population genetics research
Long-term field release of bioluminescent Sinorhizobium meliloti strains to assess the influence of a recA mutation on the strains' survival
Selbitschka W, Keller M, Miethling-Graff R, et al. Long-term field release of bioluminescent Sinorhizobium meliloti strains to assess the influence of a recA mutation on the strains' survival. MICROBIAL ECOLOGY. 2006;52(3):583-595.A field release experiment was carried out to study the fate of the isogenic, firefly luciferase (luc) gene-tagged Sinorhizobium meliloti strains L1 (RecA(-)) and L33 (RecA(+)) in the environment. Both strains were released at concentrations of approximately 10(6) cfu g(-1) soil in replicate and randomized field plots, which had been sown with alfalfa (Medicago sativa). The survival of both strains during the following 7 years could be subdivided into three phases: a sharp decline for more than two orders of magnitude within the first 4 months (phase I), followed by fluctuations around an average number of 10(4) cfu g(-1) soil for nearly 4 years (phase II), and a further decline to approximately 60 cfu g(-1) (phase III). At most sampling dates, no significant differences in the survival of both strains were detected, indicating that the recA gene function was dispensable under these environmental conditions. During the field inoculation, both strains were dispersed accidentally by wind in small numbers to noninoculated field plots. Strain L33 established at a concentration of more than 10(3) cfu g(-1) soil with subsequent seasonal fluctuations. Although strain L1 must have been disseminated to a similar extent, it could never be recovered from noninoculated field plots, indicating that the recA mutation interfered with the strain's capability to establish there. At the beginning of the field experiment, an indigenous alfalfa-nodulating population was below the limit of detection. In the following years, however, an indigenous population arose, which finally outcompeted both strains for saprophytic growth and alfalfa nodulation. RecA(-) strain L1 was outcompeted for alfalfa nodulation slightly faster than its RecA(+) counterpart L33. The diversity of the indigenous population was characterized by employing the Enterobacterial Repetitive Intergenic Consensus polymerase chain reaction fingerprint method. Typing of 2731 root nodule isolates revealed a total of 38 fingerprint groups. More than 80% of the isolates could be grouped into six dominant fingerprint groups, indicating that a few dominant bacterial strain types had outcompeted the released strains