Cytosolic glutamine synthetase is present in the phloem sap of rice (Oryza sativa L.)

Tomohiro Tanaka, Nobuo Suzui, Hiroaki Hayashi, Tomoyuki Yamaya, Tadakatsu Yoneyama

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


The presence of glutamine synthetase (GS) in the rice sieve tube was examined. Proteins in the rice phloem sap from leaf sheaths were separated by sodium dodecylsulfate-polyacrylamide gel electrophoresis, transferred to polyvinylidine difluoride membranes and immunoblotted with anti-GS1 antibody. A cross-reacting band, thought to be GS1, was detected in the phloem sap. Moreover, the phloem sap contained a significant amount of GS transferase activity. Previous studies have shown that the concentrations of substrates and cofactors in the rice phloem sap are sufficient for cytosolic GS reaction. These data suggest that physiologically active GS1 is present in rice phloem sap, which might convert glutamate to glutamine in vivo.

Original languageEnglish
Pages (from-to)102-106
Number of pages5
JournalSoil Science and Plant Nutrition
Issue number1
Publication statusPublished - 2009 Feb


  • GS1
  • Glutamine synthetase
  • Nitrogen
  • Phloem sap
  • Rice (Oryza sativa L.)

ASJC Scopus subject areas

  • Soil Science
  • Plant Science


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