The molecular taxonomy of three endemic Central Asian species of Ranunculus(Ranunculaceae)

Shyryn Almerekova,Yerlan Turuspekov,Natalia Shchegoleva,Saule Abugalieva,Ruslan Kalendar

doi:10.1371/journal.pone.0240121

Abstract

Worldwide, the genus Ranunculus includes approximately 600 species and is highly genetically diverse. Recent taxonomic reports suggest that the genus has a monophyletic origin, divided into two subgenera, and consists of 17 sections. The Central Asian country of Kazakhstan has 62 species of the genus that have primarily been collected in the central part of the country. The latest collection trips in southern parts of the country have led to the description of a wider distribution area for Ranunculus and the identification of a new species Ranunculus talassicus Schegol. et A.L. Ebel from Western Tien Shan. Therefore, in this study, attempts were made to assess the molecular taxonomic positions of R. talassicus and two other species endemic to the Central Asian region R. karkaralensis Schegol. and R. pskemensis V.N. Pavlov in relation to other species of the genus, using internal transcribed spacer (ITS) molecular genetic markers. The ITS-aligned sequences of 22 local Central Asian accessions and 43 accession sequences available in the National Center for Biotechnology Information (NCBI) database allowed the construction of a maximum parsimony phylogenetic tree and a Neighbor-Net network. The results indicated that R. talassicus and R. pskemensis could be assigned to section Ranunculastrum. Additionally, an assessment of the network suggested that R. pskemensis was the rooting taxon for the group of species containing R. talassicus, and that R. illyricus L. and R. pedatus Waldst. & Kit. were founders of a prime rooting node for the Ranunculastrum section of the genus. The ITS-aligned sequences showed that R. karkaralensis was indifferent with respect to three other species in the Ranunculus section of the genus, i.e., R. acris L., R. grandifolius C.A. Mey., and R. subborealis Tzvelev. The study indicated that the assessments of ITS-based phylogenetic tree and Neighbor-Net network provided new insights into the taxonomic positions of three endemic species from Central Asia.

Highlights

The Ranunculaceae Juss., or buttercup family, has a worldwide distribution and comprises more than 2500 species belonging to 59 genera
The total variability of the internal transcribed spacer (ITS) sequences was 34.85%, with 26 nucleotide sites appearing as singletons, and 159 sites registered as parsimonious informative sites
The alignment of ITS sequences for the 65 Ranunculus samples collected in Kazakhstan, neighbouring Central Asian countries, and Genbank was used for the construction of Maximum Likelihood (ML), Maximum Parsimony (MP), and NJ phylogenetic trees

Summary

Introduction

The Ranunculaceae Juss., or buttercup family, has a worldwide distribution and comprises more than 2500 species belonging to 59 genera. The largest cosmopolitan genus of the family is Ranunculus L., which contains approximately 600 species distributed worldwide [1, 2]. Tamura’s classification subdivided the genus into seven subgenera: Pallasiantha, Coptidium, Ficaria, Batrachium, Crymodes, Gampsoceras, and Ranunculus. In this classification, the subgenus Ranunculus was further subdivided into 20 sections [2]. 200 species of Ranunculus based on sequences of the muclear ITS (nrITS) region [9] showed a high level of similarity to previous chloroplast DNA restriction site analyses [8] and differed from the previous classification based on phenetic studies Phylogenetic analyses of c. 200 species of Ranunculus based on sequences of the muclear ITS (nrITS) region [9] showed a high level of similarity to previous chloroplast DNA restriction site analyses [8] and differed from the previous classification based on phenetic studies

Objectives

Methods

Results

Discussion

Conclusion