Rhizobium tropici chromosomal citrate synthase gene

Appl Environ Microbiol. 1995 Nov;61(11):3992-7. doi: 10.1128/aem.61.11.3992-3997.1995.

Abstract

Two genes encoding citrate synthase, a key enzyme in the Krebs cycle, have been found in Rhizobium tropici. One of them is in the bacterial chromosome, while the other is in the symbiotic plasmid. We sequenced the chromosomal gene and found that it is very similar to the previously reported plasmidic gene sequence in its structural region but not in its regulatory region. The chromosomal gene is able to complement an Escherichia coli citrate synthase mutant. In R. tropici, a mutant in the chromosomal citrate synthase gene has a diminished citrate synthase activity (in free-living bacteria), a diminished nodulation capacity, and forms nitrogen-fixing nodules. In contrast, the citrate synthase double mutant forms ineffective nodules devoid of bacteroids and forms less nodules than the single chromosomal mutant. It is inferred that both genes are functional and required during the nodulation process in R. tropici.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Chromosomes, Bacterial / genetics*
  • Citrate (si)-Synthase / genetics*
  • DNA Primers / genetics
  • DNA, Bacterial / genetics
  • Escherichia coli / enzymology
  • Escherichia coli / genetics
  • Genes, Bacterial*
  • Genetic Complementation Test
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Phenotype
  • Plasmids / genetics
  • Rhizobium / enzymology*
  • Rhizobium / genetics*
  • Sequence Homology, Amino Acid
  • Sequence Homology, Nucleic Acid
  • Symbiosis

Substances

  • DNA Primers
  • DNA, Bacterial
  • Citrate (si)-Synthase

Associated data

  • GENBANK/L41815