Modification of plant architecture through the expression of GA 2-oxidase under the control of an estrogen inducible promoter in Arabidopsis thaliana L

Ian S. Curtis, Atsushi Hanada, Shinjiro Yamaguchi, Yuji Kamiya

    Research output: Contribution to journalArticlepeer-review

    20 Citations (Scopus)

    Abstract

    The gibberellin (GA) 2-oxidase (PcGA2ox1) from bean catalyses the 2β-hydroxylation of some precursor and bioactive GAs resulting in their inactivation. We have expressed PcGA2ox1 under the control of the estrogen receptor-based chemical-inducible system, XVE, to modify plant architecture and assess whether transgene expression is localised. Applications of estradiol to the shoot apical region of inducible PcGA2ox1 overexpressors exhibited delays in both bolting (maximum of 46 days) and times to anthesis (maximum of 62 days) compared to wildtype (36 and 41 days, respectively), without altering leaf area. Individual treated leaves showed signs of epinasty and became dark green; such estradiol-treated regions maintained these 'green-islands' well beyond the onset of leaf senescence. Northern blots revealed that the PcGA2ox1 transcript could be detected within 1 h of treatment. The level of PcGA2ox1 transcript appeared to peak 3-5 h after estradiol application in both high and semi expressors. Quantitative Reverse Transcription (QRT)-PCR data showed that GA down-regulated genes AtGA3ox1, AtGA20ox1 and SCARECROW-LIKE3 (SCL3) were up-regulated and the GA up-regulated genes AtGA2ox1 and AtExp1 were down-regulated in estradiol-treated leaves of inducible PcGA2ox1 overexpressors; neighbouring non-treated leaves showing no significant changes. Further molecular analyses revealed that expression of the transgene was confined to estradiol-treated leaves only. Expression profiles of GA down- and up-regulated genes in inducer-treated overexpressors appeared to be synchronised with changes in leaf phenotype. These observations suggest that PcGA2ox1 under the control of the XVE system can be used effectively to alter plant architecture in Arabidopsis by localised 2β-hydroxylation of GAs at estradiol-treated sites.

    Original languageEnglish
    Pages (from-to)957-967
    Number of pages11
    JournalPlanta
    Volume222
    Issue number6
    DOIs
    Publication statusPublished - 2005 Dec 1

    Keywords

    • Chemical-inducible system
    • Estrogen receptor
    • GA 2-oxidase
    • Gene expression
    • Gibberellin

    ASJC Scopus subject areas

    • Genetics
    • Plant Science

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