ABSTRACT
OBJECTIVE: To establish a method for the rapid identification of Alismatis Rhizoma based on single nucleotide polymorphism (SNP) molecular marker. METHODS: Total genomic DNA was extracted using improved DNA extraction kit, and the internal tran scribed spacer 2 (ITS2) regions were amplified and annotated by using the hidden Markov model (HMM). In addition, the ITS2 sequences of Alisma orientale and Alisma plantago-aquatica were aligned through Clustal-W, and then SNP was detected to identify Alismatis Rhizoma. RESULTS: The length of A. orientale and A. plantago-aquatica ITS2 sequences was 311 bp. No intra-specific variation was found among the samples of two species, respectively. One stable SNP (A/T) was detected at 165 bp in ITS2 region which was useful for identification of the two species. The result was confirmed by NJ tree method. Furthermore, authentication of commercial Alismatis Rhizoma by SNP molecular marker and NJ tree method indicated that only two medicinal samples (7%) were A. orientale and the others (93%) were A. plantago-aquatica which was not recorded in the Chinese Pharmacopoeia. CONCLUSION: SNP molecular marker can stably and accurately distinguish Alismatis Rhizoma in the market and can offer scientific basis for protection of germplasm resources and cultivation of Alisma.
ABSTRACT
OBJECTIVE: To identify the commercial medicinal materials and decoction pieces of Lycii Cortex and its adulterants using DNA barcoding technology. METHODS: A total of 137 samples, including 105 voucher samples belonging to nine species, seven GenBank sequences, and 25 test samples were involved in this study. Experiments were performed in accordance with the DNA barcoding standard operating procedures (DNA barcoding SOP) to get the ITS2 sequences. A DNA barcode database of Lycii Cortex and its adulterants were successfully constructed using 112 ITS2 sequences, which were amplified from the voucher samples and downloaded from the GenBank. This database was used to identify the commercial medicinal materials and decoction pieces of Lycii Cortex. RESULTS: The lengths of the ITS2 regions of the Lycii Cortex were 212-230 bp. The ITS2 sequences could clearly distinguish Lycii Cortex and its adulterants. Fifty percent of the commercial samples gained the ideal genomic DNA for the sequence amplification. Using the established database, the above-mentioned sequences were authenticated as Lycium chinense. CONCLUSION: ITS2 Sequence may be a suitable marker for the identification of Lycii Cortex and its adulterants. The DNA barcode databaseof Lycii Cortex and its adulterants constructed in this study are able to successfully identify the raw materials of the commercial medicinal materials and decoction pieces of Lycii Cortex that are currently available in the market.