Novel characteristics (intra and ex planta) of indigenous serogroups of Rhizobium meliloti.

摘要

his thesis presents novel findings regarding symbiotic, physiological, and antigenic characteristics of representatives from an indigenous soil-borne population of Rhizobium meliloti. Nodules were sampled from 'Vernal', 'Anchor', and 'Saranac' alfalfa, and the isolates analyzed serologically. Rhizobium meliloti serogroup 31 was identified as a dominant nodule occupant, with a greater and more consistent nodule occupancy rate on Vernal (60%) compared to Anchor (24%) or Saranac (36%) The symbiotic effectiveness of the parent isolate of serogroup 31 was evaluated on each cultivar over four harvests in a greenhouse study. Only inoculated Vernal responded with an increase in shoot dry weight and N;Several novel phenomena were shown to hinder the production of fluorescent antibody conjugates specific to serogroup 31. An indirect fluorescent methodology, using the biotin-avidin system, was developed to successfully detect and specifically discriminate members of serogroup 31 from other strains of R. meliloti. Using this technique, members of serogroup 31 were found to comprise 17% of the total R. meliloti population in soil samples with a recent history of alfalfa cultivation.;Isolates of Rhizobium meliloti serogroups 31 and 17 were grown in yeast extract mannitol broth (YEM) containing NaCl or polyethylene glycol (PEG). At water potentials below