Evolution of Flower Development: from Phenotypes to Genes
Martin, Cathie , Lara-Palmero, Sara , Nichols, John , Baumann, Kim , Perez-Rodrigues, Maria , Glover, Beverley .
The contribution of petal cell shaping to pollinator attraction.
Conical petal epidermal cells significantly enhance the attractiveness of a flower to its pollinators. This occurs in a number of ways. Conical cells enhance colour saturation, they may provide tactile cues, they reduce petal reflexing, they increase petal temperature and they may enhance scent emission. Our field trials of pollination success have shown that cell morphology has a more significant effect on pollinator attraction and seed set than floral pigmentation in Antirrhinum majus. The different effects of conical petal cells may be of different degrees of significance in the interactions of particular pollinators with different plant species and it is likely that loss of this specialised cell type is associated with shifts in pollination system. Conical cells are widely distributed in both monocots and eudicots and are morphologically similar in diverse plants, suggesting that they are ancestral, but have been independently lost, multiple times. We hypothesise that the loss of the conical cell form is associated with shifts in pollination system, from, for example, pollination by nectar-gatherers to pollination by pollen-gatherers. Study of the genes controlling cell shaping in A.majus has identified a number of MIXTA-like genes encoding transcription factors that contribute to petal cell shaping and the additional effects determining the specialization of petals to pollinator attraction. In the genus Solanum, most species also have conical petal epidermal cells. However the cells of the petals of woody nightshade, Solanum dulcamara, are flat. We have shown that this difference in epidermal cell shaping is the result of changes in the expression of MIXTA-like genes. The loss of conical cells in this species may allow for greater petal reflexing providing an adaptation to pollinator attraction in this buzz-pollinated species. We have also investigated the change in function of the MIXTA-like genes resulting from the changes to their expression patterns in S.dulcamara.
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1 - John Innes Centre, Cell and Developmental biology, Norwich Research Park, Colney, Norwich, Norfolk, NR4 7UH, United Kingdom
2 - Universidad de Málaga, Departamento de Biología Molecular y Bioquímica, Málaga, 29071 Málaga, Spain
3 - University of Cambridge, Department of Plant Sciences, Downing Street, Cambridge
Presentation Type: Symposium or Colloquium Presentation
Location: Stevens 4/Hilton
Date: Wednesday, July 11th, 2007
Time: 9:30 AM