The nolL gene from Rhizobium etli determines nodulation efficiency by mediating the acetylation of the fucosyl residue in the nodulation factor

Mol Plant Microbe Interact. 1999 Mar;12(3):236-46. doi: 10.1094/MPMI.1999.12.3.236.


The nodulation factors (Nod factors) of Rhizobium etli and R. loti carry a 4-O-acetyl-L-fucosyl group at the reducing end. It has been claimed, based on sequence analysis, that NolL from R. loti participates in the 4-O-acetylation of the fucosyl residue of the Nod factors, as an acetyl-transferase (D. B. Scott, C. A. Young, J. M. Collins-Emerson, E. A. Terzaghi, E. S. Rockman, P. A. Lewis, and C. E. Pankhurst. Mol. Plant-Microbe Interact. 9:187-197, 1996). Further support for this hypothesis was obtained by studying the production of Nod factors in an R. etli nolL::Km mutant. Chromatographic and mass spectrometry analysis of the Nod factors produced by this strain showed that they lack the acetyl-fucosyl substituent, having a fucosyl group instead. Acetyl-fucosylation was restored upon complementation with a wild-type nolL gene. These results indicate that the nolL gene determines 4-O-acetylation of the fucosyl residue in Nod factors. Analysis of the predicted NolL polypeptide suggests a transmembranal location and that it belongs to the family of integral membrane transacylases (J. M. Slauch, A. A. Lee, M. J. Mahan, and J. J. Mekalanos. J. Bacteriol. 178:5904-5909, 1996). NolL from R. loti was also proposed to function as a transporter; our results show that NolL does not determine a differential secretion of Nod factors from the cell. We also performed plant assays that indicate that acetylation of the fucose conditions efficient nodulation by R. etli of some Phaseolus vulgaris cultivars, as well as of an alternate host (Vigna umbellata).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylation
  • Amino Acid Sequence
  • Bacterial Proteins*
  • Base Sequence
  • DNA Primers
  • Fucose / metabolism*
  • Gene Deletion
  • Gene Expression Regulation, Bacterial / drug effects
  • Genistein / pharmacology
  • Molecular Sequence Data
  • Nitrogen Fixation / genetics*
  • Plant Proteins / chemistry
  • Plant Proteins / genetics*
  • Plant Proteins / metabolism
  • Rhizobium / genetics*
  • Sequence Homology, Amino Acid


  • Bacterial Proteins
  • DNA Primers
  • Plant Proteins
  • noIL protein, Rhizobium etli
  • Fucose
  • Genistein

Associated data

  • GENBANK/AF047684