Transfer of nitrate reductase genes of the cyanobacterium Nostoc muscorum into Rhizobium japonicum.
Transformation of Rhizobium japonicum CB1809 was studied using DNA from the cyanobacterium Nostoc muscorum ATCC 27893. A spontaneous nitrate reductase deficient (Nar-) mutant (NR-6) of R. japonicum CB1809 was isolated with a frequency of 8.4 X 10(-7). Streptomycin (Sm) and Neomycin (Neo) resistance markers were introduced into strain NR-6, and the resulting strain was designated NR-6 SmR NeoR. Experiments with cyanobacterial DNA and live cells of strain NR-6 SmR NeoR indicated transformation of nitrate reductase (nar) genes of N. muscorum into this strain. This conclusion was supported by the reversion frequency of strain NR-6 SmR NeoR to Nar+ and the transformation frequency when recipient cells were exposed to N. muscorum DNA (with heat-treated DNA as control). Comparisons of growth, nitrate uptake, assimilatory nitrate reductase activity and nodulation of parent CB1809, NR-6 SmR NeoR and five transformant clones (Nar+) suggest that there may be considerable homology between the nar genes of R. japonicum CB1809 and N. muscorum.
D000458:Cyanobacteria / Q000201:enzymology / Q000235:genetics*; D004247:DNA / Q000235:genetics; D004352:Drug Resistance, Microbial; D005796:Genes; D009154:Mutation; D009355:Neomycin / Q000494:pharmacology; D009565:Nitrate Reductases / Q000235:genetics*; D012231:Rhizobium / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*; D013307:Streptomycin / Q000494:pharmacology; D014170:Transformation, Genetic
D004247:DNA; D009565:Nitrate Reductases; D009355:Neomycin; D013307:Streptomycin