Identification of Medicinal Aconitum Species Based on ITS2 Sequences and Analysis of Genetic Relationship / 中国实验方剂学杂志

ObjectiveThe internal transcribed spacer （ITS） 2 region of ribosomal gene， a DNA barcode， was employed to identify 12 medicinal Aconitum species and the genetic relationship among the species was analyzed. MethodA total of 30 samples of the 12 species were collected. The DNA was extracted with spin column plant genomic DNA kit and the universal primers of ITS2 sequence were used for polymerase chain reaction （PCR） amplification， followed by electrophoresis detection and bi-directional sequencing. The yielded sequences were aligned and spliced by CodonCode Aligner 17.0 and sequence variation was analyzed by MEGA 7.0. The secondary structure was predicted by ITS2 Database and the neighbor-joining （NJ） method was applied to generate the phylogenetic tree. ResultThe ITS2 sequences of the 12 species were 220-221 bp， with the average guanine and cytosine （GC） content of 64.09%， 140 variable sites， 137 informative sites， and 81 conservative sites. The intraspecific genetic distance （K2P） was smaller than the interspecific genetic distance. According to the secondary structures of ITS2 sequences and NJ cluster analysis， A. scaposum， A. sinomontanum， and A. barbatum had close genetic relationship， while the rest nine showed close kinship， particularly A. soongaricum and A. yinschanicum. ConclusionITS2 sequence is of great value for the molecular identification and genetic relationship determination of Aconitum， which provides a new method for the study of ethnomedicine.

Molecular Identification of Tibetan Codonopsis Plants Based on ITS2 and psbA-trnH Barcode / 中国实验方剂学杂志

ObjectiveTo identify the molecular biology of various species of Tibetan Codonopsis plants based on internal transcribed spacer（ITS）2 and psbA-trnH sequence barcode technology. MethodThe genomic DNA of 28 Tibetan Codonopsis plant samples from four species （Codonopsis canescens，C. foetens subsp. nervosa，C. pilosula， and C. thalictrifolia var. mollis） were extracted，and the ITS2 and psbA-trnH sequences were amplified and sequenced. The related sequences of 81 Tibetan Codonopsis plant samples belonging to 15 species were downloaded from GenBank， and MEGA 6.0 was used for sequence comparison and mutation site analysis. The GC content and genetic distance within and between species were calculated. Additionally， phylogenetic trees were constructed by maximum likelihood （ML） method， neighbor-joining （NJ） method，and unweighted pair-group method with arithmetic means （UPGMA） . ResultAccording to the mutation site，C. canescens， C. pilosula，C. pilosula subsp. tangshen， C. pilosula var. modesta，C. bhutanica，C. clematidea，C. lanceolata，C. subglobosa and C. foetens were distinguished. In the phylogenetic trees，the optimal clustering effects for ITS2 and psbA-trnH sequences were obtained using the ML method and the UPGMA method， respectively， and 12 species were effectively clustered. ConclusionITS2 and psbA-trnH sequences have a high identification rate for species of single origin，but there are still some limitations in identifying variants and original variants. This study provides basis for the identification of affinity relationship and clinical safety of Tibetan Codonopsis plants.