Identification of the medicinal plant Dipsacus asperoides from three other species in genus Dipsacus (Dipsaceae) by internal transcribed spacer of ribosomal deoxyribonucleic acid (rDNA ITS)

Abstract

The internal transcribed spacer of ribosomal deoxyribonucleic acid (rDNA ITS including ITS1, 5.8S, and ITS2) of six populations of Dipsacus asperoides and two adulterants (Dipsacus japonicus and Dipsacus chinensis), were sequenced by polymerase chain reaction (PCR) products sequencing method and a phylogenetic tree was constructed by neighbor-joining method with Mega 3.1 software. The sequences of rDNA ITS region ranged from 596 to 602 bp. In comparison to the sequences among intraspecies of D. asperoides, variation of the rDNA ITS was significant among D. asperoides and its adulterants. Together with the reported rDNA ITS regions of Dipsacus mitis in GenBank (Accession No. AY236187), total of 122 variable sites and 29 informative sites were present among these interspecies. Notably, 14 of the total 29 informative sites were species-characteristic traits. Such a differentiation in the ITS sequence, could provide molecular markers to distinguish D. asperoides from the adulterants at the DNA level and to complement conventional morphological methods. And the phylogenetic analysis was conducted to obtain the information on variation and evolution of the four species. Based on sequence divergence and phylogenetic pattern, the results illustrated that D. asperoides was more closely related to D. mitis than to D. chinensis and to D. japonicus.   Key words: Dipsacus, Dipsacus asperoides, phylogenetic analysis, internal transcribed spacer of ribosomal deoxyribonucleic acid (rDNA ITS).