BackgroundMedicinal plant trade is important for local livelihoods. However, many medicinal plants are difficult to identify when they are sold as roots, powders or bark. DNA barcoding involves using a short, agreed-upon region of a genome as a unique identifier for species– ideally, as a global standard.Research QuestionWhat is the functionality, efficacy and accuracy of the use of barcoding for identifying root material, using medicinal plant roots sold by herbalists in Marrakech, Morocco, as a test dataset.MethodologyIn total, 111 root samples were sequenced for four proposed barcode regions rpoC1, psbA-trnH, matK and ITS. Sequences were searched against a tailored reference database of Moroccan medicinal plants and their closest relatives using BLAST and Blastclust, and through inference of RAxML phylograms of the aligned market and reference samples.Principal FindingsSequencing success was high for rpoC1, psbA-trnH, and ITS, but low for matK. Searches using rpoC1 alone resulted in a number of ambiguous identifications, indicating insufficient DNA variation for accurate species-level identification. Combining rpoC1, psbA-trnH and ITS allowed the majority of the market samples to be identified to genus level. For a minority of the market samples, the barcoding identification differed significantly from previous hypotheses based on the vernacular names.Conclusions/SignificanceEndemic plant species are commercialized in Marrakech. Adulteration is common and this may indicate that the products are becoming locally endangered. Nevertheless the majority of the traded roots belong to species that are common and not known to be endangered. A significant conclusion from our results is that unknown samples are more difficult to identify than earlier suggested, especially if the reference sequences were obtained from different populations. A global barcoding database should therefore contain sequences from different populations of the same species to assure the reference sequences characterize the species throughout its distributional range.

Extensive efforts have been made to resolve the phylogeny of the large coffee family (Rubiaceae) based on molecular data. As a result, several small tribes have been described, but the phylogenies and generic delimitations for many of these groups remain unclear. This study focuses on the small tribe Danaideae that belongs to subfamily Rubioideae and whose generic limits have not previously been addressed with molecular data. It is the sole rubiaceous tribe distributed almost entirely in the Western Indian Ocean region, with the exception of the East African Danais xanthorrhoea. The tribe consists of three genera: Danais, Payera (including the monotypic genus Coursiana), and Schismatoclada. We present the first molecular phylogenetic study of Danaideae including representatives from all three genera and using Bayesian and maximum parsimony methods and sequence data from nuclear DNA (nrITS) and chloroplast DNA (petD, psbA-trnH, rpl32-trnLUAG, rpsl6). Our main objectives were to rigorously test the monophyly of Danaideae as currently circumscribed and assess phylogenetic relationships within the tribe. The findings of this study shed light on the colonization history of the tribe. Our analyses reaffirm the monophyly of Danaideae and Danais but reveal the paraphyly of Payera and Schismatoclada. The close relationship between the three Danaideae genera and Coursiana is supported. However, we found very little support for the inclusion of the latter genus in Payera as proposed earlier. The tribe is resolved in two morphologically distinct major lineages, the highly supported Danais clade with lianescent habit (= Danais sensu Buchner & Puff) and the Payera-Schismatoclada clade with arborescent habit. The Malagasy and Mauritian specimens of Danais fragrans are not closely related, and we restrict D. fragrans to the Mauritian taxa and resurrect Danais lyallii Baker to accommodate the Malagasy D. fragrans. According to our analysis, Madagascar is the origin of all species of Danaideae occurring in the Comoro archipelago, East Africa, and Mauritius. The Mauritian and East African Danais each is the result of a single colonization event, while there were at least two independent colonization events to the Comoros.

The Hymenodicteae-Naucleeae clade is a predominantly Paleotropical group with 220 species in 28 genera. The phylogenetic relationships and generic limits within Naucleeae have previously been assessed using combined molecular-morphological data, however the status of some genera remains questionable. The evolutionary relationships within Hymenodictyeae have never been investigated before. We performed phylogenetic analyses of the Hymenodictyeae-Naucleeae clade using nuclear [nrETS; nrITS] and chloroplast [ndhF; rbcL; rps16; trnT-F] data and a large sampling of both tribes. Our study supports the monophyly of the tribes, all subtribes of Naucleeae (Adininae, Breoniinae, Cephalanthinae, Corynantheinae, Mitragyninae, Naucleinae, and Uncariinae), and the Hymenodictyeae genera Hymenodictyon and Paracorynanthe. In Naucleeae, the monotypic genera Adinauclea, Metadina, and Pertusadina are nested within Adina, Mitragyna within Fleroya, Ludekia, Myrmeconauclea, and Ochreinauclea within Neonauclea, and Burttdavya and Sarcocephalus within Nauclea. Corynanthe and Pausinystalia are mutually paraphyletic. We provisionally maintain the current generic status of Neonauclea and its allied genera, pending further study. In sum, we recognize 17 genera in Naucleeae: