Developmental and Structural Section
Bartlett, Madelaine , Specht, Chelsea .
CYCLOIDEA-like genes and the evolution of floral symmetry in Zingiberales.
Processes leading to current angiosperm diversity remain a key question in evolutionary biology, with particular focus on the morphological diversity of flowers. One important aspect of floral form, from both an ecological and developmental standpoint, is symmetry. The monocotyledonous order Zingiberales presents an ideal system for the study of floral symmetry: there have been multiple shifts in symmetry that can be reliably mapped onto their phylogeny. In Zingiberales, two patterns of zygomorphy exist as a result of differential stamen suppression. In Strelitziaceae, Lowiaceae and Musaceae, the adaxial anti-petalous stamen is suppressed. In Heliconiaceae and the ginger families (Cannaceae, Marantaceae, Costaceae, Zingiberaceae), an anti-sepalous stamen is suppressed resulting in a second pattern of zygomorphy as compared to that of the earlier diverging lineages. We have identified candidate gene families that may have been recruited and adapted in the Zingiberales to generate the observed patterns of floral symmetry in the order, one of these gene families is the CYCLOIDEA/ TEOSINTE BRANCHED1 (CYC/TB1)-like genes. The TCP transcription factor CYC and its homologs have been implicated in the control of floral symmetry and stamen number in diverse lineages. We present a phylogenetic reconstruction of identified CYC/TB1 homologs in Zingiberales. Patterns of gene duplication and divergence leading to potential morphological innovation and changes in symmetry in the Zingiberales are examined. We present evidence that there have been previously unreported CYC/TB1-like duplications in Zingiberales. We also present CYC/TB1-like expression data in diverse Zingiberales taxa with differing floral symmetries. Our work will provide insight into the evolution of symmetry, a key floral trait
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1 - University of California, Berkeley, Plant and Microbial Biology, 111 Koshland Hall, Berkeley, CA, 94720-3102, United States
2 - University of California, Berkeley, Plant and Microbial Biology, 111 Koshland Hall MC 3102, Berkeley, California, 94720-3102, USA
Presentation Type: Oral Paper:Papers for Sections
Date: Tuesday, July 29th, 2008
Time: 1:45 PM