A Phylogenetic Study Of Pleurospermum Hoffm.and Related Genera In China

The genus Pleurospermum(Apiaceae subfamily Apioideae),with ca.50 species distributed in E Europe and N Asia,especially diverse in the Himalayan region and western China,is taxonomically complex,especially with regard to its generic circumscription.Within the genus,39 species are recognized in China,with 22 of these being endemic.In this study,based on the greatest sampling of Pleurospermum s.l.to date,with an emphasis on its Chinese endemic taxa,we ascertained their phylogenetic placement in Apioideae,and investigated the phylogenetic relationships of Pleurospermum and its close relatives by means of molecular systematics.Furthermore,a comprehensive sorting for medicinal plants in Chinese Apiaceae had also been conducted.(1)Molecular phylogenetics of Pleurospermum and its putative allies based on nrDNA ITS sequencesWe obtained nrDNA ITS sequences from 56 new accessions of Chinese Pleurospermum species and its relatives.These data along with published ITS matrix from selected Apioideae(for a total of 2967 accessions with 36 species of Pleurospermum)were subjected to a maximum likelihood analysis:(1)The genus Pleurospermum is not monophyletic as previously noted,with its species fell within six clade in Apioideae.besides the three major clades reported previously(Sinodielsia Clad,Acronema Clade and Pleurospermeae),its members also allied with East-Asia Clade,Komarovieae and Pleurospermopsis Clade;(2)Most Chinese endemic Pleurospermum species fell within tribe Pleurospermeae;(3)Excluding Hymenolaena and Pseudotrachydium,all other close relatives of Pleurospermum are not monophyletic;(4)The circumscription of Pleurospermum and Pterocyclus were revised,with the former comprising Pleurospermum s.str.and other eight species mainly distributed in China,and the latter now consisted of three species;(5)Pleurospermum bicolor(Franch.)Norman ex Pan&Watson was transferred into Pleurospermopsis as P.bicolor(Franch.)J.Zhou&J.Wei as the results of molecular and morphological comparison;(6)The Pleurospermum nanum Franch,which was previously transferred to Physospermopsis as P.nana(Franchet)Pimenov&Kljuykov was supported in our analysisIn this study,we sorted members of the polyphyletic Pleurospermum into major clades of Apioideae,assessed relationships of these members to its close relatives in each clades.The phylogenetic results obtained will lay the foundation for further phylogenetic studies and nomenclatural transfers(2)Collection and sorting of medicinal plants in Chinese ApiaceaeA comprehensive sorting for medicinal plants in Apiaceae has been done in this study by combining market survey with literature review,including its species,distribution,price and substitutes.According to the statistics,there are 65 genera and 262 species of medicinal plants of Apiaceae in China,with medicinal part mostly from radix and rhizoma.Sichuan province is the most abundant in distribution and planting resources,with about 137 species,followed by Yunnan,Hubei and Gansu provinces.Furthermore,we summarized the genuine and substitues of 11 medicinal plants,e.g.Bupleurum.Angelica and Peucedanum etc,which found that the medicinal plants of Apiaceae were substituted or mixed in different taxonomic ranks.This study would contribute to reduce the risk of medicine misuse,as well as explore other plants of Apiaceae with potential medicinal value,to achieve sustainable development of related industries.