Recent Topics Posters
Ingram, Amanda , Christin, Pascal-Antoine , Osborne, Colin .
Molecular phylogenies falsify an hypothesized C4 reversion in Eragrostis walteri (Poaceae)
Eragrostis walteri Pilg. (Chloridoideae: Poaceae) has been a species of great interest to evolutionary biologists since the 1984 discovery by Ellis that E. walteri had leaf blade anatomy characteristic of species employing C3 photosynthesis. This was a striking revelation, given that every other Eragrostis species that has been studied, and in fact almost all other chloridoid grasses, are known to use C4 photosynthesis and possess the expected Kranz anatomy. Due to its presumed phylogenetic position, therefore, E. walteri has frequently been cited as a likely candidate for the rare evolutionary reversion from C4 to C3 photosynthesis. Here we report confirmation from δ13C analyses that E. walteri is a C3 plant and evidence from phylogenetic analyses of DNA sequence data from two accessions of E. walteri that indicate the species has been misplaced taxonomically. Sequences from both the plastid and nuclear genomes place E. walteri well outside Chloridoideae and indicate affinities with the C3 subfamily Arundinoideae. These new genetic data thus falsify the long-standing hypothesis of C4 to C3 reversion in E. walteri and highlight a need to reconsider the taxonomic status of this species.
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1 - Wabash College, Department of Biology, PO Box 352, Crawfordsville, IN, 47933, USA
2 - Brown University, Ecology and Evolutionary Biology, 80 Waterman St, Box G-W, Providence, RI, 02912, USA
3 - University of Sheffield, Department of Animal and Plant Sciences, Sheffield, S10 2TN, UK
Presentation Type: Recent Topics Poster
Location: Hall A/Convention Center
Date: Monday, August 2nd, 2010
Time: 5:30 PM