Chimeric AGAMOUS repressor induces serrated petal phenotype in Torenia fournieri similar to that induced by cytokinin application
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The homeotic protein AGAMOUS (AG) terminates the floral meristem and promotes the development of stamens and carpels in <i>Arabidopsis</i>. Disruption of its function or expression of the chimeric AG repressor (<i>AGSRDX</i>) results in redundant petals, known as a double flower phenotype. To investigate whether this morphological change in <i>Arabidopsis</i> is applicable to ornamental flowers to increase their horticultural value, we introduced <i>AGSRDX</i> into torenia (<i>Torenia fournieri</i> Lind.) plants. Transgenic torenia plants expressing <i>AGSRDX</i> showed no redundancy in petal number, although they exhibited serration in petal margins, anthocyanin accumulation and morphological change in the stigma surface, and formation of extra vascular bundles in petals and styles. Anatomical observation of petals and styles revealed that these phenotypes are highly similar to those of forchlorfenuron (CPPU)-treated torenia plants especially in the derangement of vascular bundles. Phenotypes similar to <i>AGSRDX</i> transgenic torenia plants were also observed when the chimeric repressors for torenia C-function genes <i>TfFAR</i> or <i>TfPLE1</i>, homologs of <i>Antirrhinum FARINELLI</i> and <i>PLENA</i> respectively, were expressed. These results suggest that the morphological changes in <i>AGSRDX</i> transgenic torenia plants are induced by the disruption of C-function. These novel phenotypes might be caused by the modification of cytokinin-dependent regulation in vascular bundle formation and ectopic expression of the chimeric repressors in all whorls by the cauliflower mosaic virus (CaMV) 35S promoter.
- Plant tissue culture letters
Plant tissue culture letters 25(1), 45-53, 2008-03-01
Japanese Society for Plant Cell and Molecular Biology