Genetic diversity and biogeography of T. officinale inferred from multi locus sequence typing approach.

Nasim Ahmad Yasin,Xiangdong Hu,Aqeel Ahmad,Tehmina Anjum,Yanju Pang,Mohammadjavad Jafari,Monika Bielec,Shakeel Ahmed,Tzen-Yuh Chiang,Basharat Ali,Fatemeh Sefidkon,Waheed Akram,Qian Cai,Matteo Ciprian,Shuang Dong,Xuebo Hu,Sheng Hu,Xiaohua Li

doi:10.1371/journal.pone.0203275

Abstract

Taraxacum officinale (Asteraceae) is widely distributed weedy plant used as a traditional medicinal herb. The population genetics and historical biogeography of this plant have remained relatively unexplored. This study explores phylogeny, population genetics and ancestral reconstructions adopting multi locus sequence typing (MLST) approach. MLST sequences dataset was generated from genomics and chloroplast DNA sequences obtained from 31 T. officinale haplotypes located in 16 different countries. Phylogenetic analysis distributed these haplotypes in well differentiated geographic clades. The study suggested a close relationship between Europe and adjacent Asian countries. Populations of these regions predominantly formed common haplogroups, showed considerable level of gene flow and evidence for recombination events across European and Asian population. Biogeographical inferences obtained by applying statistical dispersal-vicariance analysis (S-DIVA) and Bayesian binary MCMC (BBM) analysis showed that T. officinale was putatively originated in Europe. Molecular clock analysis based on ITS dataset suggested that the divergence between Europe and East Asian populations can be dated to 1.07 Mya with subsequent dispersal and vicariance events. Among different spatial process long distance seed dispersal mediated by wind had potentially assisted the population expansion of T. officinale.

Highlights

Dandelion (Taraxacum officinale; Compositae-Lactuceae) is a group of highly invasive wild plants with worldwide distribution
Our findings suggest that the genus T. officinale prevails complex phylogeny and single molecular barcode loci has little power to reveal deep phylogeny
Use of multi locus sequence typing approach based on datasets of different barcode loci are more efficient in resolving complex T. officinale phylogeny and evolutionary events

Summary

Introduction

Dandelion (Taraxacum officinale; Compositae-Lactuceae) is a group of highly invasive wild plants with worldwide distribution. The representative species of this genus are Taraxacum officinale and T. erythrospermum. In USA, T. officinale is found abundantly in cold regions. This indicates that it is basically acquainted with America through Alaska [2]. A remarkable phenomenon is common existence of geographical parthenogenesis [6] Another situation worth mentioning is the occurrence of several geographically restricted complexes of sympatric diploid sexuality and closely related agamosperms comprising higher levels of variations and dynamics [7]. These processes are discussed in more detail by Kirschner et al, 2003 [8]

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Discussion

Conclusion