Identification of a cDNA from the arbuscular mycorrhizal fungus Glomus intraradices that is expressed during mycorrhizal symbiosis and up-regulated by N fertilization

Mol Plant Microbe Interact. 2002 Apr;15(4):360-7. doi: 10.1094/MPMI.2002.15.4.360.


A cDNA library was constructed with RNA from Glomus intraradices-colonized lettuce roots and used for differential screening. This allowed the identification of a cDNA (Gi-1) that was expressed only in mycorrhizal roots and was of fungal origin. The function of the gene product is unknown, because Gi-1 contained a complete open reading frame that was predicted to encode a protein of 157 amino acids which only showed little homology with glutamine synthetase from Helicobacter pylori. The time-course analysis of gene expression during the fungal life cycle showed that Gi-1 was expressed only during the mycorrhizal symbiosis and was not detected in dormant or germinating spores of G. intraradices. P fertilization did not significantly change the pattern of Gi-1 expression compared with that in the unfertilized treatment, whereas N fertilization (alone or in combination with P) considerably enhanced the Gi-1 transcript accumulation. This increase in gene expression correlated with plant N status and growth under such conditions. The possible role of the Gi-1 gene product in intermediary N metabolism of arbuscular mycorrhizal symbiosis is further discussed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Blotting, Northern
  • Bradyrhizobium / drug effects
  • Bradyrhizobium / growth & development
  • Cloning, Molecular
  • DNA, Complementary / chemistry
  • DNA, Complementary / genetics
  • Fertilizers
  • Fungi / genetics*
  • Fungi / growth & development
  • Gene Expression Regulation, Fungal / drug effects
  • Molecular Sequence Data
  • Nitrogen / pharmacology
  • Phosphorus / pharmacology
  • Plant Roots / genetics
  • Plant Roots / microbiology
  • Sequence Analysis, DNA
  • Sequence Homology, Amino Acid
  • Soybeans / genetics
  • Soybeans / microbiology
  • Symbiosis*
  • Up-Regulation / drug effects
  • Water / pharmacology
  • Water / physiology


  • DNA, Complementary
  • Fertilizers
  • Water
  • Phosphorus
  • Nitrogen

Associated data

  • GENBANK/AJ315337