| Abstract Detail
Tuesday Morning Contributed Talks Barkman, Todd [1], Martins, Talline [2], Todd, Sarah [1], Stout, John [1]. Molecular phylogenetic tests of convergent and parallel evolution of floral scent evolution in the Solanaceae. INDEPENDENT evolutionary gains of floral scent compound production are common among angiosperms. These independent gains could be due to evolutionary convergence, whereby unrelated biosynthetic enzymes arise in different species from different ancestral proteins to produce the same compound. However, it is also possible that these independent gains could be due to parallel evolution, whereby different species attain the ability to produce a compound using orthologous enzymes that are closely related and arose from the same ancestral protein. The Solanaceae provides an excellent opportunity to investigate the hypothesis of parallel or convergent evolution because methyl salicylate (MeSA) likely evolved in the floral scent of multiple species independently. To test these hypotheses in the Solanaceae, we first assessed tissue-specific levels of expression of two paralogous genes that can produce MeSA: salicylic acid methyltransferase (Samt) and benzoic/salicylic acid methyltransferase (Bsmt). Samt was expressed at high levels in the flowers (relative to leaves) in the MeSA-producing species Cestrum nocturnum and Datura wrightii. Bsmt was expressed at high levels in Nicotiana suaveolens. Heterologous expression of the up-regulated sequences from D. wrightii, C. nocturnum, and N. suaveolens verified that the proteins encoded by these sequences catalyze the formation of MeSA from SA. Collectively, while it appears that the independent gain of MeSA production in the flowers of C. nocturnum and D. wrightii is the result of parallel evolution, the evolution of MeSA production in N. suaveolens is due to convergence.
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1 - Western Michigan University, Department of Biological Sciences, Kalamazoo, MI, 49008, USA
2 - University of Wisconsin, Department of Botany, Madison, MI, 53706, USA
Keywords:
none specified
Session: SOL04-9
Location: Ballroom AB/Monona Terrace
Date: Tuesday, July 25th, 2006
Time: 11:10 AM
Abstract ID:319 |
