title: Generation of phytate-free seeds in Arabidopsis through disruption of inositol polyphosphate kinases.
abstract: Phytate (inositol hexakisphosphate, IP6) is a regulator of intracellular signaling, a highly abundant animal antinutrient, and a phosphate store in plant seeds. Here, we report a requirement for inositol polyphosphate kinases, AtIPK1 and AtIPK2beta, for the later steps of phytate synthesis in Arabidopsis thaliana. Coincident disruption of these kinases nearly ablates seed phytate without accumulation of phytate precursors, increases seed-free phosphate by 10-fold, and has normal seed yield. Additionally, we find a requirement for inositol tetrakisphosphate (IP4)/inositol pentakisphosphate (IP5) 2-kinase activity in phosphate sensing and root hair elongation. Our results define a commercially viable strategy for the genetic engineering of phytate-free grain and provide insights into the role of inositol polyphosphate kinases in phosphate signaling biology.
authors.affiliation: Department of Pharmacology and Cancer Biology, Howard Hughes Medical Institute, Duke University Medical Center, Durham, NC 27710, USA.
authors.forename: Jill
authors.initials: J
authors.lastname: Stevenson-Paulik
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Bastidas
authors.forename: Shean-Tai
authors.initials: ST
authors.lastname: Chiou
authors.forename: Roy A
authors.initials: RA
authors.lastname: Frye
authors.forename: John D
authors.initials: JD
authors.lastname: York
mesh_terms: D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D017343:Genes, Plant; D005818:Genetic Engineering; D009154:Mutation; D010641:Phenotype; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics / Q000378:metabolism*; D010833:Phytic Acid / Q000096:biosynthesis / Q000378:metabolism*; D012639:Seeds / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D010833:Phytic Acid; D017853:Phosphotransferases (Alcohol Group Acceptor)