Developmental and Structural Section
Gleissberg, Stefan , Wreath, Sara , Bartholmes, Conny .
Silencing of EcFLO, a FLORICAULA-like gene from Eschscholzia californica, affects flowering in a morphology- and lineage-specific manner.
FLORICAULA/LEAFY-like (FLO) genes are plant-specific transcriptional regulators of various developmental processes in flowering plant shoots. In Arabidopsis or other core eudicots, FLO genes have been implicated in vegetative to reproductive phase transition, floral meristem identity, phyllotaxy, inflorescence architecture, and leaf dissection. To explore the role of FLO genes in a species basal to core eudicots with distinct morphological characteristics, we are using an improved virus-induced gene silencing (VIGS) protocol in Eschscholzia californica, the California Poppy.
Following inoculation of seedling hypocotyls with a Tobacco Rattle Virus (TRV) construct containing the Eschscholzia FLORICAULA ( EcFLO ) homolog, a high percentage of plants exhibited defects in the flowering region. Plants infected with the empty virus were indistinguishable from untreated plants.
Leaf morphology, phyllotaxy, and branching pattern in the flowering region appear normal in EcFLO-VIGS plants, despite expression of the gene in the peripheral zone of vegetative and reproductive shoot apical meristems and in leaflets.
Altered floral morphology after downregulation of EcFLO suggests a repeated initiation of the floral developmental program and relaxed determinacy of the floral meristem. Interestingly, all flowers eventually form a gynoecium that is often fertile, indicating that EcFLO may not be required for gynoecium initiation. No conversion of floral organs to foliage leaves was observed, instead a range of homeotic transformations among floral organs resulted in mosaic organs. Our observations are being discussed in terms of the lineage- and morphology-specific configuration of a widely conserved function of FLORICAULA/LEAFY genes in floral morphogenesis.
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1 - Ohio University, Environmental and Plant Biology, Porter Hall, Athens, Ohio, 45701, USA
2 - Ohio University, Department of Environmental and Plant Biology, 315 Porter Hall, Athens, OH, 45701, USA
Presentation Type: Oral Paper:Papers for Sections
Date: Tuesday, July 29th, 2008
Time: 11:15 AM