The GA2 Locus of Arabidopsis thaliana Encodes ent-Kaurene Synthase of Gibberellin Biosynthesis

Shinjiro Yamaguchi, Tai Ping Sun, Hiroshi Kawaide, Yuji Kamiya

    Research output: Contribution to journalArticle

    140 Citations (Scopus)

    Abstract

    The ga2 mutant of Arabidopsis thaliana is a gibberellin-deficient dwarf. Previous biochemical studies have suggested that the ga2 mutant is impaired in the conversion of copalyl diphosphate to ent-kaurene, which is catalyzed by ent-kaurene synthase (KS). Over-expression of the previously isolated KS cDNA from pumpkin (Cu-curbita maxima) (CmKS) m the ga2 mutant was able to complement the mutant phenotype. A genomic clone coding for KS, AtKS, was isolated from A. thaliana using CmKS cDNA as a heterologous probe. The corresponding A. thaliana cDNA was isolated and expressed in Escherichia coli as a fusion protein. The fusion protein showed enzymatic activity that converted [3H]copalyl diphosphate to [3H]ent-kaurene. The recombinant AtKS protein derived from the ga2-1 mutant is truncated by 14 kD at the C-terminal end and does not contain significant KS activity in vitro. Sequence analysis revealed that a C-2099 to T base substitution, which converts Gln-678 codon to a stop codon, is present in the AtKS cDNA from the ga2-1 mutant. Taken together, our results show that the GA2 locus encodes KS.

    Original languageEnglish
    Pages (from-to)1271-1278
    Number of pages8
    JournalPlant physiology
    Volume116
    Issue number4
    DOIs
    Publication statusPublished - 1998 Jan 1

    ASJC Scopus subject areas

    • Physiology
    • Genetics
    • Plant Science

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