Identification of two fix loci controlling the expression of nif genes in Rhizobium meliloti 41

1989 ◽  
Vol 215 (2) ◽  
pp. 345-348 ◽  
Author(s):  
Z. Banfalvi ◽  
V. Petkova ◽  
M. Lados ◽  
K. Slaska-Kiss ◽  
P. Putnoky ◽  
...  
Keyword(s):  
Rhizobium Meliloti ◽  
Nif Genes

scholarly journals Clustering of nitrogen fixation (nif) genes in Rhizobium meliloti.

1982 ◽  
Vol 149 (1) ◽  
pp. 221-228 ◽  
Author(s):  
D Corbin ◽  
G Ditta ◽  
D R Helinski
Keyword(s):  
Nitrogen Fixation ◽  
Rhizobium Meliloti ◽  
Nif Genes

Symbiotic gene probes hybridize to cryptic plasmids of indigenous Rhizobium meliloti

1988 ◽  
Vol 34 (5) ◽  
pp. 703-707 ◽  
Author(s):  
L. R. Barran ◽  
E. S. P. Bromfield
Keyword(s):  
Dna Sequences ◽  
Rhizobium Meliloti ◽  
Dna Probes ◽  
Cryptic Plasmid ◽  
Nodule Development ◽  
Nif Genes ◽  
Symbiotic Gene ◽  
Gene Probes ◽  
Cryptic Plasmids

DNA probes for host specific nodulation (hsn) common nodulation (nod), exopolysaccharide (exo), nodule development (ndv) and nitrogenase structural (nif) genes were used to examine a collection of symbiotically effective, genotypically distinct isolates of indigenous Rhizobium meliloti for reiteration of symbiotic DNA sequences on cryptic plasmids. Nineteen of 30 isolates possessed at least one cryptic plasmid with reiterated DNA sequences, and of these isolates 15, 5, and 1 contained cryptic plasmids that hybridized to hsn, nif, and nod gene probes respectively; both hsn and nif probes hybridized to a single cryptic plasmid in each of two isolates. The exo and ndv probes did not hybridize to cryptic plasmids in any of the 30 isolates of R. meliloti.

EFFECTS OF SOIL ACIDITY ON RHIZOBIA NUMBERS, NODULATION AND NITROGEN FIXATION BY ALFALFA AND RED CLOVER

1977 ◽  
Vol 57 (2) ◽  
pp. 197-203 ◽  
Author(s):  
W. A. RICE ◽  
D. C. PENNEY ◽  
M. NYBORG
Keyword(s):  
Nitrogen Fixation ◽  
Soil Ph ◽  
Soil Acidity ◽  
Field Experiments ◽  
Rhizobium Meliloti ◽  
Acid Soils ◽  
Red Clover ◽  
Ion Concentration ◽  
Hydrogen Ion Concentration ◽  
Greenhouse Experiments

The effects of soil acidity on nitrogen fixation by alfalfa (Medicago sativa L.) and red clover (Trifolium pratense L.) were investigated in field experiments at 28 locations, and in greenhouse experiments using soils from these locations. The pH of the soils (limed and unlimed) varied from 4.5 to 7.2. Rhizobia populations in the soil, nodulation, and relative forage yields (yield without N/yield with N) were measured in both the field and greenhouse experiments. Rhizobium meliloti numbers, nodulation scores, and relative yields of alfalfa decreased sharply as the pH of the soils decreased below 6.0. For soils with pH 6.0 or greater, there was very little effect of pH on any of the above factors for alfalfa. Soil pH in the range studied had no effect on nodulation scores and relative yields of red clover. However, R. trifolii numbers were reduced when the pH of the soil was less than 4.9. These results demonstrate that hydrogen ion concentration is an important factor limiting alfalfa growth on acid soils of Alberta and northeastern British Columbia, but it is less important for red clover. This supports the continued use of measurements of soil pH, as well as plant-available Al and Mn for predicting crop response to lime.

scholarly journals Electrophoretic separation of the three Rhizobium meliloti replicons.

1991 ◽  
Vol 173 (16) ◽  
pp. 5173-5180 ◽  
Author(s):  
B W Sobral ◽  
R J Honeycutt ◽  
A G Atherly ◽  
M McClelland
Keyword(s):  
Rhizobium Meliloti ◽  
Electrophoretic Separation
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