Phylogenetic relationships within Ferula sect. Merwia (Apiaceae- Ferulinae) inferred from nrDNA and cpDNA markers

Ferula L., as a large genus in the Umbelliferae with 180-185 species, is distributed only in the Old World. There are 25 mostly medicinal species within the Ferula sect. Merwia, of which 14 species are distributed in Iran. A molecular phylogenetic study of the Iranian species using two nrDNA (ITS and ETS) and two cpDNA (rpL32―trnL(UAG) and rps16― trnK(UUU)) markers was undertaken to determine the phylogenetic relationships among species and evaluate their potential value in taxonomic treatment of the genus. The Maximum Likelihood and Bayesian Inferences trees revealed that the section contained three geographically separated subclades. Also, F. assa-foetida has appeared as two geographic ecotypes in Iran; one group contains the populations distributed in lower altitudes in the Centre of Iran and the other includes the populations from higher altitudes in Zagros Mt. in the south of Iran. Ferula alliacea is placed close to the eastern elements of the sect. Merwia. Similarly, the position of F. lutensis as well as F. latisecta is confirmed within the section. The used cpDNA regions could not define the boundaries of infraspecific taxa of Ferula species such as F. assa-foetida within the sect. Merwia, while they contributed to separating different species of other sections of the genus and also allied genera (Leutea). Accordingly, the most informative region was the ETS nrDNA which may contain more nucleotide substitution. In our analyses, Leutea turcomanica is located close to the other Leutea species.