L- Myo-inositol 1-phosphate synthase in the aquatic fern Azolla filiculoides

• Published in: Plant physiology and biochemistry Vol. 42; no. 2; pp. 97 - 102
• Main Authors: Oren Benaroya, Rony, Zamski, Eli, Tel-Or, Elisha
• Format: Journal Article
• Language: English
• Published: Paris Elsevier Masson SAS 01-02-2004; Elsevier
• Subjects: Azolla; Biological and medical sciences; Cations, Divalent - metabolism; Enzymes; Ferns - enzymology; Ferns - genetics; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Plant; Kinetics; L- myo-inositol 1-phosphate synthase; Metabolism; Metal binding; Myo-Inositol-1-Phosphate Synthase - genetics; Myo-Inositol-1-Phosphate Synthase - metabolism; Phosphate storage; Plant Leaves - enzymology; Plant physiology and development; IRRI; Phosphate storage; L- myo-inositol 1-phosphate synthase; Metal binding; INPS; Azolla; PCR; L-myo-inositol 1-phosphate synthase; Isomerases; myo-Inositol-1-phosphate synthase; Enzyme; Intramolecular lyases; Pteridophyta; Azolla filiculoides; Filicineae
• ISSN: 0981-9428; 1873-2690
• DOI: 10.1016/j.plaphy.2003.11.008

L-
Myo-inositol 1-phosphate synthase (INPS EC 5.5.1.4) catalyzes the conversion of D-glucose 6-phosphate to L-
myo-inositol 1-phosphate. INPS is a key enzyme involved in the biosynthesis of phytate which is a common form of stored phosphates in higher plants. The present study monitored the increase of INPS expression in
Azolla filiculoides resulting from exposure to inorganic phosphates, metals and salt stress. The expression of INPS was significantly higher in
Azolla plants that were grown in rich mineral growth medium than those maintained on nutritional growth medium. The expression of INPS protein and corresponding mRNA increased in plants cultured in minimal nutritional growth medium when phosphate or Zn
2+, Cd
2+ and NaCl were added to the growth medium. When employing rich mineral growth medium, INPS protein content increased with the addition of Zn
2+, but decreased in the presence of Cd
2+ and NaCl. These results indicated that accumulation of phytate in
Azolla is a result of the intensified expression of INPS protein and mRNA, and its regulation may be primarily derived by the uptake of inorganic phosphate, and Zn
2+, Cd
2+ or NaCl.