Phylogenetic relationships between Oxytropis DC. and Astragalus L.species native to an Old World diversity center inferred from nuclear ribosomal ITS and plastid matK gene sequences

Abstract

Oxytropis and Astragalus represent one of the largest angiosperm genera complexes. Although phylogenetic studies of this complex exist, the evolutionary relationships among Astragalus and Oxytropis species sharing similar habitats in the Old World have not been studied in detail. The phylogenetic relationships among 13 Oxytropis and 56 Astragalus species native to Turkey were inferred from nucleotide sequence variations in the nuclear ribosomal internal transcribed spacer (ITS) and chloroplast maturase-like protein (matK) gene regions. In addition to our samples, 36 Oxytropis ITS and 6 Oxytropis matK sequences were retrieved from GenBank and included in the analysis. Phylogenies derived from a maximum likelihood analysis of the sequences indicated that Oxytropis and Astragalus genera are more likely monophyletic. However, the results suggest that New World Oxytropis species did not evolve by a single adaptive radiation in the genus, but rather from different Old World lineages. The genetic divergence between genera was less when the matK region was analyzed. Although the Oxytropis species did not show high genetic diversity, one subcluster of the genus was always distinctly separated in both trees. This subcluster was formed by the species Oxytropis engizekensis Duman & Vural and O. persica Boiss., which are also regarded as synonyms in regard to several morphological characters of the genus.

Increasing phylogenetic support for explosively radiating taxa: The promise of high‐throughput sequencing for Oxytropis (Fabaceae)

“…With its broad geographic sampling, the present study is the most comprehensive contribution to understanding species relationships within Oxytropis . We confirm the monophyly of Oxytropis as sister to the strongly supported clade of Astragalus (PP = 0.99; ML = 93, MP = 93, SH = 100), as already suggested by other studies (Wojciechowski et al, ; Wojciechowski, ; Archambault & Strömvik, ; Zachary & Meyers, ; Dizkirici Tekpinar et al, , ; Kholina et al, ). We further contribute to clarify the status of several species within the genus.…”

“…argyroleuca and O . fominii (Dizkirici Tekpinar et al, ), but not with ITS of our own specimen of O . argyroleuca , which was collected from the type locality.…”

“…Therefore, the synonymy of O . argyroleuca with O. fominii is still questionable (Dizkirici Tekpinar et al, , ). Our ITS sequence of O .…”

“…In plant taxa exhibiting such morphological complexity, molecular data might provide an essential tool to resolve phylogenetic relationships, hence supporting morphology‐based taxonomical work. To date, a few molecular studies on Oxytropis have addressed taxonomic questions using a heterogeneous set of markers (Wojciechowski et al, ; Jorgensen et al, ; Artyukova et al, ; Chung et al, ; Kulshreshtha et al, ; Schönswetter et al, ; Gao et al, ; Schlee et al, ; Dizkirici Tekpinar et al, , ; Kholina et al, ). Yet, most of these studies focused on regional treatments, and only included species from geographically restricted areas.…”

“…Yet, most of these studies focused on regional treatments, and only included species from geographically restricted areas. For example, Archambault & Strömvik () focused primarily on North American Arctic species and Dizkirici Tekpinar et al (, ) and Kholina et al () investigated those from Turkey and Asian Russia, respectively. Given the taxonomic complexity of this genus, efforts towards a genus‐wide taxonomic revision are therefore especially needed.…”