Functioning haemoglobin genes in non-nodulating plants

Nature. 1988 Jan 14;331(6152):178-80. doi: 10.1038/331178a0.


Haemoglobin has previously been recorded in plants only in the nitrogen-fixing nodules formed by symbiotic association between Rhizobium or Frankia and legume or non-legume hosts. Structural similarities amongst these and animal haemoglobins at the protein and gene level suggested a common evolutionary origin. This suggests that haemoglobin genes, inherited from an ancestor common to plants and animals, might be present in all plants. We report here the isolation of a haemoglobin gene from Trema tomentosa, a non-nodulating relative of Parasponia (Ulmaceae). The gene has three introns located at positions identical to those in the haemoglobin genes of nodulating plant species, strengthening the case for a common origin of all plant haemoglobin genes. The data argue strongly against horizontal haemoglobin gene transfer from animals to plants. The Trema gene has a tissue-specific pattern of transcription and translation, producing monomeric haemoglobin in Trema roots. We have also found that the Parasponia haemoglobin gene is transcribed in roots of non-nodulated plants. These results suggest that haemoglobin has a role in the respiratory metabolism of root cells of all plant species. We propose that its special role in nitrogen-fixing nodules has required adaptation of the haemoglobin-gene regulation pathway, to give high expression in the specialized environment of the nodule.

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • DNA / genetics
  • Hemoglobins / genetics*
  • Molecular Sequence Data
  • Nucleic Acid Hybridization
  • Plant Proteins / analysis
  • Plant Proteins / genetics
  • Plants / genetics*
  • RNA / genetics
  • RNA, Messenger / analysis
  • Transcription, Genetic


  • Hemoglobins
  • Plant Proteins
  • RNA, Messenger
  • RNA
  • DNA

Associated data

  • GENBANK/Y00296