Characterization of a binding site for chemically synthesized lipo-oligosaccharidic NodRm factors in particulate fractions prepared from roots

Plant J. 1995 Feb;7(2):253-60. doi: 10.1046/j.1365-313x.1995.7020253.x.


This paper describes the characteristics of a binding site for the major, lipo-oligosaccharide Nod factor of Rhizobium meliloti in roots of the symbiotic host plant, Medicago truncatula. Chemically synthesized NodRm-IV(Ac, S, C16:2) was labelled by tritiation to a specific activity of 56 Ci mmol-1 and this ligand was shown to be biologically active in the root hair deformation assay at 10(-11) M. Binding of the ligand to a particulate fraction from roots of M. truncatula was found to be saturable and reversible with an affinity (Kd) of 86 nM and the binding characteristics were consistent with a single class of binding sites. Competition with modified Nod factors showed that the binding was independent of both the O-acetyl and the sulphyl group and did not depend on the unsaturation of the fatty acid. However, both moieties of the lipo-oligosaccharide are required for high-affinity binding since tetra-N-acetyl-chitotetraose and palmitate were found to be poor competitors of ligand binding. A binding site with analogous characteristics was also found in a similarly prepared particulate fraction of tomato roots. This binding site for Nod factors, termed NFBS1, which is present in both a leguminous and a non-leguminous plant, may have a more general role than symbiosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites
  • Carbohydrate Sequence
  • Lipopolysaccharides / chemical synthesis
  • Lipopolysaccharides / chemistry
  • Lipopolysaccharides / metabolism*
  • Medicago sativa / microbiology
  • Molecular Sequence Data
  • Sinorhizobium meliloti / metabolism
  • Symbiosis


  • Lipopolysaccharides
  • Nod factor IV, Rhizobium meliloti