The role of heterologous nifAc product in the regulation of nif expression in Agrobacterium tumefaciens.
The plasmids pCK5, pCK3, pSZ36, and pSZ23-CA, which carried constitutive nifAc gene of Azotobacter chroococcum and Klebsiella pneumoniae were transferred into A. tumefaciens C58/pGV3850 with triparental mating. The growth rate of these transconjugants was similar to the wild type. Nitrogenase synthesis was demonstrated by Western blotting, in the presence of 10 mmol/L NH4+, and the nitrogenase activity was restored to 73%, 24%, 11%, and 62%, respectively. The results showed that the regulative gene of nitrogen fixation in A. chroococcum and K. pneumoniae played a regulative role for the expression of A. tumefaciens nitrogen fixation gene. Among them, the role of A. chroococcum nifAc gene was the strongest, the fusion plasmid pSZ23-CA which carried nifA-ntrC gene of K. pneumoniae was stronger, and the nifAc gene of K. pneumoniae was weak.
Zhang
J
J
Institute of Microbiology, Academia Sinica, Beijing, China.
Zhang
J
J
D016960:Agrobacterium tumefaciens / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D015153:Blotting, Western; D003227:Conjugation, Genetic; D004587:Electrophoresis, Agar Gel; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D005798:Genes, Bacterial; D009586:Nitrogen Fixation / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology*
D001426:Bacterial Proteins; C061338:NifA protein, Bacteria; D014157:Transcription Factors