title: Origin and seed phenotype of maize low phytic acid 1-1 and low phytic acid 2-1.
abstract: Phytic acid (myo-inositol-1, 2, 3, 4, 5, 6-hexakisphosphate or Ins P(6)) typically represents approximately 75% to 80% of maize (Zea mays) seed total P. Here we describe the origin, inheritance, and seed phenotype of two non-lethal maize low phytic acid mutants, lpa1-1 and lpa2-1. The loci map to two sites on chromosome 1S. Seed phytic acid P is reduced in these mutants by 50% to 66% but seed total P is unaltered. The decrease in phytic acid P in mature lpa1-1 seeds is accompanied by a corresponding increase in inorganic phosphate (P(i)). In mature lpa2-1 seed it is accompanied by increases in P(i) and at least three other myo-inositol (Ins) phosphates (and/or their respective enantiomers): D-Ins(1,2,4,5,6) P(5); D-Ins (1,4,5,6) P(4); and D-Ins(1,2,6) P(3). In both cases the sum of seed P(i) and Ins phosphates (including phytic acid) is constant and similar to that observed in normal seeds. In both mutants P chemistry appears to be perturbed throughout seed development. Homozygosity for either mutant results in a seed dry weight loss, ranging from 4% to 23%. These results indicate that phytic acid metabolism during seed development is not solely responsible for P homeostasis and indicate that the phytic acid concentration typical of a normal maize seed is not essential to seed function.
authors.affiliation: United States Department of Agriculture-Agricultural Research Service, National Small Grain Germplasm Research Facility, P.O. Box 307, Aberdeen, Idaho 83210, USA. vraboy@uidaho.edu
authors.forename: V
authors.initials: V
authors.lastname: Raboy
authors.forename: P F
authors.initials: PF
authors.lastname: Gerbasi
authors.forename: K A
authors.initials: KA
authors.lastname: Young
authors.forename: S D
authors.initials: SD
authors.lastname: Stoneberg
authors.forename: S G
authors.initials: SG
authors.lastname: Pickett
authors.forename: A T
authors.initials: AT
authors.lastname: Bauman
authors.forename: P P
authors.initials: PP
authors.lastname: Murthy
authors.forename: W F
authors.initials: WF
authors.lastname: Sheridan
authors.forename: D S
authors.initials: DS
authors.lastname: Ertl
mesh_terms: D004586:Electrophoresis / Q000379:methods; D007295:Inositol Phosphates / Q000737:chemistry / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D009154:Mutation; D010641:Phenotype; D010710:Phosphates / Q000302:isolation & purification / Q000378:metabolism; D020161:Physical Chromosome Mapping; D010833:Phytic Acid / Q000096:biosynthesis / Q000378:metabolism*; D012639:Seeds / Q000254:growth & development / Q000502:physiology*; D013237:Stereoisomerism; D003313:Zea mays / Q000235:genetics / Q000254:growth & development / Q000502:physiology*
chemical_list: D007295:Inositol Phosphates; D010710:Phosphates; D010833:Phytic Acid