Springer Nature is making SARS-CoV-2 and COVID-19 research free. View research | View latest news | Sign up for updates

Structure and role in symbiosis of the exoB gene of Rhizobium leguminosarum bv trifolii

  • 63 Accesses

  • 12 Citations

Abstract

The Rhizobium leguminosarum bv trifolii exoB gene has been isolated by heterologous complementation of an exoB mutant of R. meliloti. We have cloned a chromosomal DNA fragment from the R. leguminosarum bv trifolii genome that contains an open reading frame of 981 bp showing 80% identity at the amino acid level to the UDP-glucose 4-epimerase of R. meliloti. This enzyme produces UDP-galactose, the donor of galactosyl residues for the lipid-linked oligosaccharide repeat units of various heteropolysaccharides of rhizobia. An R. leguminosarum bv trifoliiexoB disruption mutant differed from the wild type in the structure of both the acidic exopolysaccharide and the lipopolysaccharide. The acidic exopolysaccharide made by our wild-type strain is similar to the Type 2 exopolysaccharide made by other R. leguminosarum bv trifolii wild types. The exopolysaccharide made by the exoB mutant lacked the galactose residue and the substitutions attached to it. The exoB mutant induced the development of abnormal root nodules and was almost completely unable to invade plant cells. Our results stress the importance of exoB in the Rhizobium-plant interaction.

This is a preview of subscription content, log in to check access.

Author information

Additional information

Received: 31 May 1996 / Accepted: 18 December 1996

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Sánchez-Andújar, B., Coronado, C., Philip-Hollingsworth, S. et al. Structure and role in symbiosis of the exoB gene of Rhizobium leguminosarum bv trifolii . Mol Gen Genet 255, 131–140 (1997). https://doi.org/10.1007/s004380050481

Download citation

  • Key wordsRhizobium leguminosarum bv trifolii
  • Trifolium subterraneum
  • Trifolium repens
  • exoB gene
  • Exopolysaccharide