Effectiveness of cpDNA sequencing data trnH-psbA in classification of the genus Polygala (Polygalaceae) in Iran.

Background and Aim: Polygala L. is the largest genus of the nearly cosmopolitan family Polygalaceae, well-known for its zygomorphic, papilionate flowers in raceme inflorescence comprising more than ۷۰۰ species in the world, naturally distributed in Eurasia Range. The genus includes ۷ species in the Flora of Iran. In terms of taxonomy and classification, there are many contradictions about this genus. Many species have synonymous names and the species boundaries are not clear. Little research has been done on these plants in the world. This includes pollen morphology, flower ontogeny, morphology, and phylogeny of Caamembeca and Polygala. However, no research has yet been done on Iranian species of the genus Methods: In this study we present a phylogenetic analysis of ۷ Iranian species of Polygala using trnH-psbA۳ intergenic spacer. To this we added ۸ previously sequenced data from Genbank. For the current phylogenetic analysis, fresh specimens were collected from natural habitats and dried in silica-gel. Total genomic DNA was extracted from leaves by CTAB method. Plastid trnH-psbA region were amplified by PCR method, using Amplicon Master Mix and Methabion primers. The PCR products were sequenced, automatically aligned in MUSCLE with default settings and manually adjusted in PAUP software. We performed phylogenetic analyses of plastid DNA in PAUP with ۱۰۰۰ bootstrap replicate, simple addition of taxa, tree bisection reconnection (TBR), branch swapping, multrees option.Results: This analysis provides the preparation a bootstrap ۵۰% majority rule consensus tree, ۲۱۶ best trees, consistency index (CI) ۶.۹, retention index (RI) ۰.۷۱ and homoplasy index (HI) ۰.۳. In this analysis ۵۱۲ characters were involved, out of which ۱۱۲ characters were informative.Conclusion: The resulted Maximum Parsimony tree demonstrate monophyly of Polygala in a strongly supported clade (with ۱۰۰ bootstraps value), a large” Polygala core group” comprising two monophyletic subgroups including majority of Iranian representatives. These subgroups were located in two subclade D: Polygala monspeliaca and P. anatolica; E: P. major, P. platyptera and Polygala sp. While P. erioptera and P. hohenackeriana formed independent paraphyletic branches. Iranian species of Polygala did not form a limited group and showed their relationships with other species. The present result supports the previous classification (presented by the Flora of Iran) for the three species.

Keywords:

classification , cpDNA , molecular phylogeny , Polygala , Polygalaceae , taxonomy , trnH-psbA