Ti plasmid and chromosomal ornithine catabolism genes of Agrobacterium tumefaciens C58

J Bacteriol. 1983 Jul;155(1):196-202. doi: 10.1128/jb.155.1.196-202.1983.


The pTiC58 plasmid noc genes of Agrobacterium tumefaciens C58 code for nopaline oxidase (nocC), nopaline permease (nocP), the inducible periplasmic protein n1 (nocB), and a function(s) required for ornithine catabolism (nocA). In addition, strains C58 and Ach-5 of A. tumefaciens have chromosomal ornithine catabolism genes. The chromosomal orc gene codes for ornithine dehydrogenase. Strain C58 is normally orc, but orc+ mutants can be selected. We have characterized both chromosomal orc and pTiC58 nocA plasmid genes. Complementation of most chromosomal orc mutants by pTiC58 restored growth on both nopaline and L-ornithine but did not restore ornithine dehydrogenase activity. We conclude that ornithine is an intermediate of nopaline degradation and that the Ti plasmid and chromosome both code for ornithine-degradative enzymes. A model for nopaline catabolism is presented.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Bacterial Proteins / genetics*
  • Chromosomes, Bacterial / physiology*
  • Genes*
  • Genes, Bacterial*
  • Kinetics
  • Membrane Transport Proteins / genetics*
  • Mutation
  • Ornithine / metabolism*
  • Oxidoreductases Acting on CH-NH Group Donors / genetics*
  • Phenotype
  • Plasmids*
  • Rhizobium / genetics*
  • Rhizobium / metabolism
  • Species Specificity


  • Bacterial Proteins
  • Membrane Transport Proteins
  • NocP protein, Agrobacterium tumefaciens
  • Ornithine
  • Oxidoreductases Acting on CH-NH Group Donors
  • nopaline dehydrogenase