Phylogenetic Relationships in the Heracleum sp. Species Complex from Iran by Using Nuclear Ribosomal DNA (ITS) and rpl32-trnL

Apiaceae is one of the largest plant families with a wide distribution including 114 genera and 363 species in Iran. Heracleum consists more than 100 species in the world, eight of them being reported in Iran including three endemic species. Based on taxonomic descriptions in Flora Iranica, the species reported in Pubescentia and Wendia sections have several morphological similarities and some display extensive geographical variation. We used the nuclear ITS and the chloroplast rpl32-trnL nucleotide sequences were used to evaluate the genetic relationships of different populations of Heracleum species. The Bayesian analysis showed that the phylogenetic tree constructed based on both nuclear and cpDNA were relatively similar, but a higher number of variable sites were observed in ITS compared to rpl32-trnL. The tree constructed by combined sequences could separate the species associated with the different sections, but could not separate the species in the sections. The results of this study indicate that the molecular data is in agreement with the morphological data reported in Flora Iranica at section level. However various populations of the different species in each section, except H. gorganicum, could not be distinguished from the others. The result suggests that more work is required for the taxonomic classification for the endemic Iranian species, including H. anisactis and H. rechingeri, as a separate species.