FLO4,OsPPDKB,ppdk,OsC4PPDK

| Categories genes  | Tags pericarp  grain  endosperm  reproductive  seed  seed development  grain filling  seed germination 
  • Information
  • PSP score
    • LOC_Os05g33570.2: 0.0664
    • LOC_Os05g33570.1: 0.1106
  • PLAAC score
    • LOC_Os05g33570.2: 0
    • LOC_Os05g33570.1: 0
  • pLDDT score
    • 85.24
  • Protein Structure from AlphaFold and UniProt
    • image
  • Publication
  • Genbank accession number
  • Key message
    • Immunoblot analysis of separated seed tissue fractions (pericarp, embryo + aleurone, seed embryo) revealed that regulatory phosphorylation of PPDK occurs in the non-green seed embryo and green outer pericarp layer, but not in the endosperm + aleurone layer
    • Our results suggest that cytosolic PPDK functions in rice to modulate carbon metabolism during grain filling
    • We have isolated a floury endosperm-4 (flo4) rice mutant with a floury-white endosperm but a normal outer portion
    • We obtained two additional alleles, flo4-2 and flo4-3, that also showed the same white-core endosperm phenotype
    • Expression analyses demonstrated that the cytosolic mRNA of OsPPDKB was induced in the reproductive organs after pollination, and greatly increased until about 10 days after fertilization
    • The single C3 organ type where PPDK is in high abundance, and, therefore, where its function is most amenable to elucidation, are the developing seeds of graminaceous cereals
    • In this report, we suggest a non-photosynthetic function for C3 PPDK by characterizing its abundance and posttranslational regulation in developing Oryza sativa (rice) seeds
    • Using primarily an immunoblot-based approach, we show that PPDK is a massively expressed protein during the early syncitial-endosperm/-cellularization stage of seed development
    • As seed development progresses from this early stage, the enzyme undergoes a rapid, posttranslational down-regulation in activity and amount via regulatory threonyl-phosphorylation (PPDK inactivation) and protein degradation
    • The modestly abundant pool of inactive PPDK (phosphorylated + dephosphorylated) that was found to persist in mature rice seeds was shown to remain largely unchanged (inactive) upon seed germination, suggesting that PPDK in rice seeds function in developmental rather than in post-developmental processes
    • White-core endosperm floury endosperm-4 in rice is generated by knockout mutations in the C-type pyruvate orthophosphate dikinase gene (OsPPDKB)
  • Connection
    • FLO4~OsPPDKB~ppdk~OsC4PPDK, OsDof25, Functions of OsDof25 in regulation of OsC4PPDK, Functions of OsDof25 in regulation of OsC4PPDK
    • FLO4~OsPPDKB~ppdk~OsC4PPDK, OsDof25, Functions of OsDof25 in regulation of OsC4PPDK, Expression studies using promoter GUS plants as well as qPCR experiments showed that OsDof25 expressed in different tissues including both photosynthetic and non-photosynthetic organs and that expression of OsDof25 was partially overlapping with the OsC4PPDK gene

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