[The different functions of glnB and glnZ from Azospirillum brasilense YU62 in the control of nitrogen fixation].
The glnB and glnZ genes of A. brasilense have 70% homology at nucleotide sequence. glnB is located in a 3.7 kb Eco RI+ PstI fragment and glnZ is located in a 3.7 kb SalI fragment. Both glnB and glnZ genes were mutagenized by Kmr cassette insertions and glnB- and glnZ- mutants were obtained. glnB- mutant did not have any nitrogenase activity, while glnZ- mutant still has nitrogenase activity. The coding regions of glnB and glnZ were cloned into pVK100 vectors and recombinant plasmids pVK-II and pVK-Z were obtained, respectively. The recombinant plasmids pVK-II and pVK-Z were introduced into glnB- and glnZ- to produce C-glnB and C-glnZ, respectively. C-glnB can restore nitrogenase activity and C-glnZ does not have effect on nitrogenase activity. When pVK-II and pVK-Z were introduced into A. brasilense Yu62 and draT-, respectively, the Yu62-II (containing pVK-II) and draT-II (containing pVK-II) have higher nitrogenase activity than that of wild type Yu62. In contrast, Yu62-Z (containing pVK-Z) and draT-Z (containing pVK-Z) has no effect on nitrogenase activity. The nifA(-)-II (containg pVK-II) and nifA(-)-Z (containing pVK-Z) still have no nitrogenase activity.
Chen
S
S
College of Biology, China Agricultural University, Beijing 100094, China.
Guan
Y
Y
Ying
J
J
Li
Z
Z
Wang
J
J
Li
J
J
D015806:Azospirillum brasilense / Q000201:enzymology / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics* / Q000502:physiology; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D016297:Mutagenesis, Site-Directed; D009586:Nitrogen Fixation / Q000235:genetics*; D009591:Nitrogenase / Q000378:metabolism*; D051922:PII Nitrogen Regulatory Proteins; D010957:Plasmids
D001426:Bacterial Proteins; C100965:GlnZ protein, Azospirillum brasilense; D051922:PII Nitrogen Regulatory Proteins; C404143:PIID regulatory protein, Bacteria; D009591:Nitrogenase