Submitted to: Genome
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/15/2014
Publication Date: 9/11/2014
Citation: He, G., Barkley, N.L., Zhao, Y., Yuan, M., Prakash, C. 2014. Phylogenetic relationships of species of genus Arachis based on geneic sequences. Genome. 57:327-334. Interpretive Summary: The genus Arachis consists of 80 species divided into nine taxonomic sections. Of all the Arachis species described, cultivated peanut (Arachis hypogaea) is the most economically valuable. Wild species tend to be more variable genetically and can be utilized as a resource to help improve cultivated peanut. This study aimed at examining the relationships among wild species from different taxonomic sections. Several genes were examined to evaluate diversity and relationships among the selected individuals. Most of the species grouped according to taxonomic section further supporting their current taxonomy.
Technical Abstract: The genus Arachis (Fabaceae), which originated in South America, consists of 80 species. Based on morphological traits and cross-compatibility among the species, the genus is divided into nine taxonomic sections, one of which, Arachis is the largest section including 30 wild species and the economically valuable cultivated peanut (A. hypogaea). To better understand the phylogenetic relationships between Arachis species, accessions were sampled from all nine taxonomic sections and seven genic sequences were utilized to reconstruct the phylogeny of the genus Arachis. Our study displayed four clades of Arachis species. Species A. triseminata was genetically isolated from all other Arachis species studied, and formed the basal clade with A. retusa and A. dardanoi from the most ancient sections Extranervosae and Heterminatae, respectively. Species of section Arachis formed a separated single clade from all other species, within which species having B and D genome clustered in one subgroup while three species characterized with an A genome grouped together in another subgroup. A divergent clade including species from five sections was sister to the clade of section Arachis. Between the sister clades and the basal clade, there was a clade containing species from the more advanced sections. Molecular phylogeny was generally congruent with the convention-based classification except the divergent lineage in this study. Phylogenetic relationships of all the Arachis species using multiple genic sequences were similar with to the phylogenies produced with a single gene.