The Phylogeny And Taxonomy Of The Genus Coptis Salisb

The genus Coptis belongs to the family Ranunculaceae(Trib.Coptideae),and contains 11-18 perennial herbs,in the world which are mainly distributed in East Asia and North America.As one of the most popular and widely used traditional Chinese medicinal herb,Huanglian has been used for over 2,000 years.However,the origin of Huanglian has long been complicated because many different species of Coptis,such as C.chinensis,C.chinensis var.brevisepala,C.omeiensis,C.deltoidei and C.teeta and sometimes various species from other different genera even families were used as the medicinal herb Huanglian.In order to infer the specific phylogenetic relationships within the genus,clarify the global species number and confirm the criteria for species delimitation,we conducted a complete phylogenetic analyses of the genus based on a comprehensive sampling of 111 samples at population level covering 17 species and 5 varieties of Coptis,including one nuclear DNA region(ITS)and four chloroplast DNA regions(mat K,rbc L,psb A-trn H and trn L-F)were employed to reconstruct the phylogeny using the maximum likelihood method and Bayesian methods.The most closely related taxa,Xanthorhiza simphcissima was selected as the outgroup.On the basis of the molecular results,a comprehensive taxonomic revision of the genus was carried out by combining literature examination,specimen study,morphological and anatomical observations.The main results were as follows:1.The BI and ML trees generated from the ITS dataset and the combined cp DNA dataset all supported the monophyly of Coptis.The structures of BI and ML trees showed that the main branches of Coptis were basically the same,the genus of Coptis includes two branches,Clade Ⅰ and Clade II.Clade Ⅰ includes two branches,all of the C.trifolia are cluster together,the other one includes C.quinquefolia and its allied species which are C.kitayamensis,C.minamitaniana,C.morii,C.quinquefolia var.shikokumontana,C.ramosa,C.trifoliolata.Clade II is consists of three branches,first branch contains C.aspleniifolia、C.occidentalis 和 C.laciniata that are endemic to North America,the second branch contains C.quinquesecta that is endemic to China,and the third branch includes C.japonica(Thunb.)Makino and its varieties,C.lutescens,and five species and one variety from mainland China.2.C.deltoidea and C.omeiensis are sisters in the ITS sequence analysis,while C.deltoidea and C.chinensis are sisters in the chloroplast association gene sequence.Combined with the results of previous studies that found it to be triploid,we deduced that C.deltoidea was a hybrid of C.chinensis and C.omeiensis,with female parent C.chinensis and male parent C.omeiensis.3.In previous studies,there were only morphological differences between C.kitayamensis 、 C.minamitaniana 、 C.morii 、 C.ramosa 、 C.trifoliolata 、 C.quinquefolia var.shikokumontana and C.quinquefolia.In the BI and ML trees constructed based on ITS and cp DNA sequences this study,the results showed that the above species are not clustered into separate monophyletic branch,but are nested within C.quinquefolia.It can be inferred that these species established on the basis of minor morphological differences are not valid and that they are in fact merely variations among different populations and individuals of C.quinquefolia.Therefore,we treated C.kitayamensis、C.minamitaniana 、 C.morii 、 C.ramosa 、 C.trifoliolata 、 C.quinquefolia var.shikokumontana as synonyms of C.quinquefolia.4.In traditional classification,Coptis in Japan is divided into two species and three varieties according to the different leaf shapes,namely C.japonica var.japonica,C.japonica var.dissecta,C.japonica var.anemoifolia and C.lutescens.In the BI and ML trees constructed based on ITS and cp DNA sequences respectively,the results showed that the three varieties of C.japonica and C.lutescens are cluster together,and they were intertwined with each other,but each species could not be clustered into a separate clade.We therefore treated C.japonica var.japonica,C.japonica var.dissecta,C.japonica var.anemoifolia and C.lutescens as synonyms of C.japonica.Based on the above research results,we ultimately identified 11 species and 1varieties of the genus Coptis: C.chinensis、C.chinensis var.brevisepala、C.omeiensis、C.deltoidea、C.teeta、C.japonica、C.quinquesecta、C.laciniata、C.aspleniifolia、C.occidentalis、C.quinquefolia、C.trifolia.We researched the original literature of each name,detailed morphological descriptions and geographic distributions were provided for each species based on specimens,and a species index were prepared.