The First Comprehensive Phylogeny of Coptis (Ranunculaceae) and Its Implications for Character Evolution and Classification.

Sheng-Dan Wu,Andrey S Erst,Sheng-Xian Yu,Florian Jabbour,Zhi-Duan Chen,Wei Wang,Yang Liu,Kun-Li Xiang,Liang Zhao,Tony Robillard

doi:10.1371/journal.pone.0153127

Abstract

Coptis (Ranunculaceae) contains 15 species and is one of the pharmaceutically most important plant genera in eastern Asia. Understanding of the evolution of morphological characters and phylogenetic relationships within the genus is very limited. Here, we present the first comprehensive phylogenetic analysis of the genus based on two plastid and one nuclear markers. The phylogeny was reconstructed using Bayesian inference, as well as maximum parsimony and maximum likelihood methods. The Swofford-Olsen-Waddell-Hillis and Bayesian tests were used to assess the strength of the conflicts between traditional taxonomic units and those suggested by the phylogenetic inferences. Evolution of morphological characters was inferred using Bayesian method to identify synapomorphies for the infrageneric lineages. Our data recognize two strongly supported clades within Coptis. The first clade contains subgenus Coptis and section Japonocoptis of subgenus Metacoptis, supported by morphological characters, such as traits of the central leaflet base, petal color, and petal shape. The second clade consists of section Japonocoptis of subgenus Metacoptis. Coptis morii is not united with C. quinquefolia, in contrast with the view that C. morii is a synonym of C. quinquefolia. Two varieties of C. chinensis do not cluster together. Coptis groenlandica and C. lutescens are reduced to C. trifolia and C. japonica, respectively. Central leaflet base, sepal shape, and petal blade carry a strong phylogenetic signal in Coptis, while leaf type, sepal and petal color, and petal shape exhibit relatively higher levels of evolutionary flexibility.

Highlights

Coptis (Ranunculaceae) is one of the pharmaceutically most important plant genera in eastern Asia
Coptis plants were for the first time recorded in the earliest monograph on Chinese material medica, Sheng Nong’s Herbal Classic, in the eastern Han dynasty (25–220 AD), and they have been used in many Chinese herbal medicines for more than two thousand years
Our aims are (1) to provide the first comprehensive molecular phylogenetic framework for Coptis containing all 15 species recognized by Tamura [19]; (2) to test the monophyly of infrageneric groupings recognized in classifications of Coptis; (3) to clarify the systematic status of C. morii, C. groenlandica, and C. lutescens; and (4) to interpret evolution of key morphological characters in a phylogenetic context

Summary

Introduction

Coptis (Ranunculaceae) is one of the pharmaceutically most important plant genera in eastern Asia. Dried rhizomes of Coptis plants are utilized for Rhizoma Coptidis (RC), a traditional Chinese medicine famous for its functions of clearing heat, dispelling dampness, and purging fire toxins [1]. Coptis plants were for the first time recorded in the earliest monograph on Chinese material medica, Sheng Nong’s Herbal Classic, in the eastern Han dynasty (25–220 AD), and they have been used in many Chinese herbal medicines for more than two thousand years. Coptis chinensis (Fig 1A) has been widely cultivated in China and its rhizomes (Fig 1B) are largely exported to other countries. Phytochemical and pharmacological studies on Coptis plants indicate that they contain a number of alkaloids, such as berberine, palmatine, jatrorrhizine, coptisine, columbamine, and epiberberine [4,5]. RC has been shown to have various clinical effects, such as suppression of fever, cessation of dampness, detoxification [6], and antibacterial, antiviral, antiinflammatory, Torrey and Gray [29]1

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