Expression of D-myo-inositol-3-phosphate synthase in soybean. Implications for phytic acid biosynthesis.
Phytic acid, a phosphorylated derivative of myo-inositol, functions as the major storage form of phosphorus in plant seeds. Myo-inositol phosphates, including phytic acid, play diverse roles in plants as signal transduction molecules, osmoprotectants, and cell wall constituents. D-myo-inositol-3-phosphate synthase (MIPS EC 5.5.1.4) catalyzes the first step in de novo synthesis of myo-inositol. A soybean (Glycine max) MIPS cDNA (GmMIPS1) was isolated by reverse transcriptase-PCR using consensus primers designed from highly conserved regions in other plant MIPS sequences. Southern-blot analysis and database searches indicated the presence of at least four MIPS genes in the soybean genome. Northern-blot and immunoblot analyses indicated higher MIPS expression and accumulation in immature seeds than in other soybean tissues. MIPS was expressed early in the cotyledonary stage of seed development. The GmMIPS1 expression pattern suggested that it encodes a MIPS isoform that functions in seeds to generate D-myo-inositol-3-phosphate as a substrate for phytic acid biosynthesis.
Hegeman
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Department of Plant Pathology, Physiology, and Weed Science, Fralin Biotechnology Center, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0346, USA.
Good
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Grabau
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EA
D001483:Base Sequence; D016384:Consensus Sequence; D017124:Conserved Sequence; D018548:Cotyledon / Q000201:enzymology; D018076:DNA, Complementary; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D019753:Intramolecular Lyases / Q000235:genetics* / Q000378:metabolism*; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D010833:Phytic Acid / Q000096:biosynthesis*; D018515:Plant Leaves / Q000201:enzymology; D018517:Plant Roots / Q000201:enzymology; D018547:Plant Stems / Q000201:enzymology; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013025:Glycine max / Q000201:enzymology* / Q000235:genetics*; D014158:Transcription, Genetic
D018076:DNA, Complementary; D007527:Isoenzymes; D012333:RNA, Messenger; D010833:Phytic Acid; D019753:Intramolecular Lyases; C105497:D-myo-inositol-3-phosphate synthase