Involved in myo-inositol synthesis. Is a key enzyme in the phytic acid biosynthesis pathway in seeds. D-glucose 6-phosphate = 1D-myo-inositol 3-phosphate Polyol metabolism; myo-inositol biosynthesis; myo-inositol from D-glucose 6-phosphate: step 1/2. Highly expressed in embryos, but transcripts are undetectable in roots, leaves, flowers and anthers. Expressed in the apical region of globular-stage embryos 2 days after anthesis (DAA). Expressed in the scutellum and aleurone layer 4 DAA. Expression in these cells increases until 7 DAA, and then gradually decreases. Induced by sucrose and glucose (PubMed:11975732). Induced by abscisic acid (ABA) (PubMed:11975732, PubMed:24467907). Plants silencing RINO1 show a low phytic acid phenotype in seeds, and high accumulation of inorganic phosphate (Pi) in seeds. Belongs to the myo-inositol 1-phosphate synthase family.