Comparison of benefit to sugarcane plant growth and 15N2 incorporation following inoculation of sterile plants with Acetobacter diazotrophicus wild-type and Nif- mutants strains

Mol Plant Microbe Interact. 2001 Mar;14(3):358-66. doi: 10.1094/MPMI.2001.14.3.358.


The ability of the nitrogen-fixing bacterial endophyte Acetobacter diazotrophicus strain PAl5 to enhance the growth of sugarcane SP70-1143 was evaluated in the growth chamber, greenhouse, and field by comparing plants inoculated with wild-type and Nif mutant MAd3A in two independent experiments. The wild-type and Nif mutant strains colonized sugarcane plants equally and persisted in mature plants. In N-deficient conditions, sugarcane plants inoculated with A. diazotrophicus PAl5 generally grew better and had a higher total N content 60 days after planting than did plants inoculated with mutant MAd3A or uninoculated plants. These results indicate that the transfer of fixed N from A. diazotrophicus to sugarcane might be a significant mechanism for plant growth promotion in this association. When N was not limiting, growth enhancement was observed in plants inoculated with either wild-type or Nif- mutants, suggesting the additional effect of a plant growth promoting factor provided by A. diazotrophicus. A 15N2 incorporation experiment demonstrated that A. diazotrophicus wild-type strains actively fixed N2 inside sugarcane plants, whereas the Nif- mutants did not.

Publication types

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

MeSH terms

  • Acetobacter / genetics*
  • Acetobacter / metabolism
  • Acetobacter / ultrastructure
  • Genes, Bacterial*
  • Microscopy, Electron
  • Mutation
  • Nitrogen Fixation* / genetics*
  • Nitrogen Fixation* / physiology
  • Nitrogen Isotopes
  • Plant Roots / growth & development
  • Plant Roots / metabolism
  • Plant Roots / microbiology
  • Poaceae / growth & development
  • Poaceae / metabolism
  • Poaceae / microbiology*
  • Symbiosis


  • Nitrogen Isotopes