Rhizobium phaseoli cytochrome c-deficient mutant induces empty nodules on Phaseolus vulgaris L.
A Rhizobium phaseoli cytochrome mutant, unable to oxidize N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD), was isolated after Mu-dl (Kan lac) mutagenesis of the wild-type strain CE-3. Mutant strain CFN4202 had sixfold less haem-c but similar levels of b type, o and aa3 cytochromes than the wild-type strain. CFN4202 strain also showed reduced NADH- and TMPD-oxidase activity than the wild-type strain. Succinate-oxidase activities were very similar. Western blot experiments, using antiserum against bovine c1 and c cytochromes, revealed that both proteins were present in CFN4202 membranes, suggesting a defect of haem binding to cytochrome c. Nodules formed by this strain in Phaseolus vulgaris did not contain bacteroids. These data suggest that the cytochrome c-aa3 chain or some other respiratory chain, containing c-type cytochromes in R. phaseoli, is essential for bacterial division during the early steps of the symbiotic interaction with the legume-host.
Departamento de Biología Molecular de Plantas, Universidad Nacional Autonoma de México, Cuernavaca, Morelos.
M
M
Soberón
G R
GR
Aguilar
F
F
Sánchez
D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D003574:Cytochrome c Group / Q000235:genetics* / Q000502:physiology; D004579:Electron Transport; D007887:Fabaceae / Q000382:microbiology*; D006418:Heme / Q000378:metabolism; D009097:Multienzyme Complexes / Q000378:metabolism; D016254:Mutagenesis, Insertional; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D009586:Nitrogen Fixation; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000378:metabolism; D010946:Plants, Medicinal; D012231:Rhizobium / Q000201:enzymology / Q000235:genetics* / Q000502:physiology; D013559:Symbiosis
D001426:Bacterial Proteins; D003574:Cytochrome c Group; D009097:Multienzyme Complexes; D006418:Heme; D010088:Oxidoreductases; C022691:succinate oxidase; C023107:NADH oxidase; D009247:NADH, NADPH Oxidoreductases