Ahlquist, Tia K. , Howard, Jamie H. , Farruggia, Frank T. , Wojciechowski, Martin F. .
A Genus-Level Phylogeny of the Inverted-Repeat Lacking Clade of Legumes.
The Inverted-Repeat lacking clade (“IRLC”), containing 52 genera, and over 4,400 species, is the largest and most widespread clade of papilionoid legumes (Leguminosae). The loss of one copy of the inverted-repeat in their plastid genomes is a synapomorphy for the IRLC in addition to a number of morphological and anatomical features. The IRLC includes a number of important agricultural crops such as the garden pea (Pisum), alfalfa (Medicago), fava bean (Vicia), clover (Trifolium), genetic/genomic model species (e.g., Medicago truncatula), and model systems for the study of nodulation/nitrogen fixation by rhizobia. Phylogenetic relationships within this group remain poorly understood due to its size, limited sampling, and widespread temperate distribution. Certain groups within this clade have been previously recognized, but their relationships are not well resolved or supported. Previous studies indicate the Asian genera Callerya, Wisteria, and Glycyrrhiza form the earliest branches in the clade. These same studies suggest there are three major subclades, one composed of Pisum, Medicago, Trifolium (“Vicioid clade”), and relatives; one (“Astragalean clade”) which contains the genus Astragalus (>2,500 spp.) and its closest relatives; and a third (“Hedysaroid clade”) which contains the genus Hedysarum and related genera. Sequences of the nuclear rDNA ITS region and the plastid matK gene were obtained from representatives of IRLC genera not sampled previously and combined with a large number of sequences already in GenBank (approx. 1000) plus appropriate outgroups in Loteae and Robinieae. Sequences of matK were analyzed using standard methods (i.e., parsimony) for the purpose of resolving relationships across the entire IRLC and its larger subclades. Sequences from nuclear rDNA ITS were analyzed with a focus on resolving relationships specifically within the larger subclades. Results from separate matK and ITS analyses along with an IRLC supertree will be presented.
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1 - Arizona State University, School of Life Sciences, P.O. Box 874601, Tempe, Arizona, 85287, USA
2 - Arizona State University, School of Life Sciences, P.O. Box 874601, Tempe, Arizona, 85287-4601, USA
3 - Arizona State University, School of Life Sciences, P.O. Box 874501, Tempe, Arizona, 85287-4501, USA
Presentation Type: Poster:Posters for BSA Sections
Location: Event Tent/Cliff Lodge
Date: Monday, July 27th, 2009
Time: 5:30 PM