Abstract Detail

Evolutionary Developmental Biology (Evo-Devo)

Zhang, Wenheng [1], Zhang, Jingbo [2], Cappellari, Simone [3], Steinmann, Victor W [4], Nikolov, Lachezar [5], Kramer, Elena M [6], Davis, Charles [7].

Divergent genetic mechanisms underlie convergences to radial floral symmetry from diverse zygomorphic flowered ancestors.

The unique floral morphology of neotropical Malpighiaceae, including their zygomorphic corollas and oil-producing calyx, is highly conserved and is thought to result from their specialized mutualism with oil bee pollinators. Our previous studies have shown that the expression of two CYCLOIDEA2-like (CYC2) genes is associated with the development of this conserved floral symmetry. This unique floral zygomorphy, however, has been lost independently in several clades, coinciding with dispersals of these clades to regions outside the ranges of specialized oil bee pollinators. Here, we investigate the expression of CYC2-like genes in five clades whose species have evolved convergent actinomorphic symmetry. We demonstrate that these convergences are always associated with alteration of the highly conserved CYC2 expression pattern observed in most New World (NW) Malpighiaceae. In NW Lasiocarpus and Old World (OW) Microsteira, the expression of CYC2-like genes has expanded to include the ventral region of the corolla. Thus, the pattern of gene expression in these species has become radialized, which is comparable to what has been reported in the radial flowered clade Cadia (Fabaceae). In striking contrast, in NW Psychopterys, OW Sphedamnocarpus, and OW Stigmaphyllon, the expression of CYC2-like genes is entirely absent or barely detectable at later stages of floral development. This is more similar to the pattern of CYC2 expression observed in radial flowered Arabidopsis (Brassicaceae). These results collectively indicate that, regardless of geographic distribution, convergences to similar floral phenotypes in this large tropical angiosperm clade have evolved via different genetic changes from an otherwise highly conserved developmental program.

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1 - Virginia Commonwealth University, Department of Biology, 1000 West Cary Street, Life Science Building, Richmond, VA, 23284-2012, USA
2 - Chinese Academy Of Sciences, Institute Of Botany, Nanxincun 20, Xiangshan, Haidian, Beijing, N/A, 100093, China
3 - University of Rochester, Department of Biology, Rochester, NY, USA
4 - Instituto de Ecología, Centro Regional del Bajío, Pátzcuaro, Mexico
5 - Max Planck Institute Of Plant Breeding Research, Carl-von-Linné-Weg 10, Köln, N/A, 50829, Germany
6 - Harvard University, 16 Divinity Avenue, Cambridge, MA, 02138, USA
7 - Harvard University, Organismic and Evolutionary Biology, Harvard University Herbaria, 22 Divinity Ave, Cambridge, MA, 02138, United States

Keywords:
CYC2-like genes
floral development
floral symmetry
Malpighiaceae
convergence
Phylogeny.

Presentation Type: Oral Paper:Papers for Topics
Session: 41
Location: Payette/Boise Centre
Date: Wednesday, July 30th, 2014
Time: 3:00 PM
Number: 41007
Abstract ID:615
Candidate for Awards:None