title: Introduction of the Escherichia coli gdhA gene into Rhizobium phaseoli: effect on nitrogen fixation.
abstract: Rhizobium phaseoli lacks glutamate dehydrogenase (GDH) and assimilates ammonium by the glutamine synthetase-glutamate synthase pathway. A strain of R. phaseoli harboring the Escherichia coli GDH structural gene (gdhA) was constructed. GDH activity was expressed in R. phaseoli in the free-living state and in symbiosis. Nodules with bacteroids that expressed GDH activity had severe impairment of nitrogen fixation. Also, R. phaseoli cells that lost GDH activity and assimilated ammonium by the glutamine synthetase-glutamate synthase pathway preferentially nodulated Phaseolus vulgaris.
mesh_terms: D003001:Cloning, Molecular; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D007887:Fabaceae; D005786:Gene Expression Regulation; D005796:Genes; D005798:Genes, Bacterial; D005969:Glutamate Dehydrogenase / Q000235:genetics*; D005970:Glutamate Synthase / Q000378:metabolism; D005974:Glutamate-Ammonia Ligase / Q000378:metabolism; D009586:Nitrogen Fixation; D009591:Nitrogenase / Q000378:metabolism; D010946:Plants, Medicinal; D010957:Plasmids; D000644:Quaternary Ammonium Compounds / Q000378:metabolism; D012231:Rhizobium / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D013559:Symbiosis
chemical_list: D000644:Quaternary Ammonium Compounds; D009591:Nitrogenase; D005970:Glutamate Synthase; D005969:Glutamate Dehydrogenase; D005974:Glutamate-Ammonia Ligase