ISSN:
1432-072X
Schlagwort(e):
Rhizobium japonicum
;
Ammonium assimilation
;
Asm- mutant
;
E. coli gdh gene
;
Symbiotic nitrogen fixation
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Biologie
Notizen:
Abstract The glutamate dehydrogenase (gdh) gene of Escherichia coli was transferred into an ammonium assimilation deficient mutant (Asm-) of Rhizobium japonicum (CJ9) using plasmid pRP301, a broad host range derivative of RP4. Exconjugants capable of growth on ammonia as sole N-source occurred at a frequency of 6.8×10-6. Assimilatory GDH (NADP+) activity was detected in the strain carrying the E. coli gdh gene and the pattern of ammonia assimilation via GDH was similar to that of the Asm+ wild type strain. However, GDH mediated ammonia assimilation was not subject to regulation by l-glutamate. Nitrogenase activity was expressed ex planta in R. japonicum CJ9 harbouring the gdh gene, however, the presence of the gdh gene did not restore symbiotic effectiveness to the CJ9 Asm- strain in nodules. The gdh plasmid was maintained in approximately 90% of the isolates recovered from soybean nodules.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00454952
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