Dwarf and delayed-flowering 1, a novel Arabidopsis mutant deficient in gibberellin biosynthesis because of overexpression of a putative AP2 transcription factor

Hiroshi Magome, Shinjiro Yamaguchi, Atsushi Hanada, Yuji Kamiya, Kenji Oda

    Research output: Contribution to journalArticlepeer-review

    250 Citations (Scopus)

    Abstract

    A novel gibberellin (GA)-deficient mutant designated dwarf and delayed-flowering 1 (ddf1) was isolated from a library of activation-tagged Arabidopsis. This mutant showed dwarfism and late-flowering, but the phenotype was rescued by exogenous GA3 like known mutants defective in GA biosynthesis. The contents of bioactive GA4 and GA1 were in fact decreased in ddf1 at least partially through the repression of biosynthetic steps catalyzed by GA 20-oxidase (GA20ox). Genetic and molecular analyses revealed that the ddf1 phenotypes are caused by increased or ectopic expression of a putative AP2 transcription factor. Overexpression of DDF2, encoding another putative AP2 transcription factor closely related to DDF1, also conferred the ddf1-like phenotype. Among genes encoding (putative) AP2 transcription factors in Arabidopsis, DDFs are phylogonetically close to dehydration-responsive element binding protein (DREB1)/C-repeat binding factor (CBF) genes, which are known to be involved in stress responses. The ddf1 mutation upregulates a stress-related gene RD29A. DDF1 mRNA is strongly induced by high-salinity stress within 1 h. Moreover, transgenic plants overexpressing DDF1 showed increased tolerance to high-salinity stress. These results suggest that DDF1 is involved in the regulation of GA biosynthesis and stress tolerance. The possible relation between the contents of endogenous GAs and acquisition of stress protection is discussed.

    Original languageEnglish
    Pages (from-to)720-729
    Number of pages10
    JournalPlant Journal
    Volume37
    Issue number5
    DOIs
    Publication statusPublished - 2004 Mar

    Keywords

    • Ap2 transcription factor
    • Arabidopsis
    • DREB1/CBF family
    • Dwarf and delayed-flowering 1
    • Dwarfism
    • Gibberellin

    ASJC Scopus subject areas

    • Genetics
    • Plant Science
    • Cell Biology

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