ISSN:
1432-2242
Keywords:
Arctic Rhizobium
;
Symbiotic efficiency
;
Nitrogenase
;
Plasmid
;
Deletion mutant
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary Mutagenesis provoked by exposure at elevated temperature of the cold-adapted, arctic Rhizobium strain N31 resulted in the generation of five deletion mutants, which exhibited loss of their smaller plasmid (200 kb), whereas the larger plasmid (〉 500 kb) was still present in all mutants. Deletion mutants did not show differences from the wild type in the antibiotic resistance pattern, the carbohydrates and organic acids utilization, and the growth rate at low temperature. However, deletion mutants differed from the wild type and among themselves in the ex planta nitrogenase activity, the nodulation index, and the symbiotic effectiveness. The deletion mutant N31.6rif r showed higher nodulation index and exhibited higher nitrogenase activity and symbiotic efficiency than the other deletion mutants and the wild type. The process of deletion mutation resulted in the improvement of an arctic Rhizobium strain having an earlier and higher symbiotic nitrogen fixation efficiency than the wild type.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00224194
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