Molecular authentication of Sarcandra glabra and its adulterants using three DNA molecular markers / 中草药

ABSTRACT

Objective: To identify Sarcandra glabra and its adulterants using three DNA molecular markers including 18 S rRNA gene, ITS2 sequence and SCAR marker, and then provide the basis for its molecular authentication. Methods: 18 S rRNA gene sequence of S. glabra was obtained by PCR amplification, cloning and sequencing, and then Blast comparison was made in NCBI. The ITS2 sequence of S. glabra was obtained by PCR amplification, sequencing and annotation in ITS2 Database. In the meanwhile, the ITS2 sequences of adulterants and other plants were collected from GenBank. Using MEGA5.5, the genetic distance was calculated between species and then the ITS2 sequences were aligned to construct a phylogenetic clustering tree. SCAR molecular marker of S. glabra was obtained by RAPD. After cloning and sequencing, specific primers were designed to amplify S. glabra and its adulterants. Results: The length of 18 S rRNA obtained in our research was 1 820 bp. Blast comparison revealed that there was 99% homology between S. glabra and Chloranthaceae, which proved to be 18 S rRNA gene of S. glabra. The length of the ITS2 sequence in our research was 500 bp. Genetic distance between S.glabra and its adulterants ranged from 0.190 to 0.219, which was far more than genetic distance among adulterants (0.000-0.074). Cluster analysis showed that S. glabra and its adulterants respectively clustered into a different branch, which was far away from other plants. In our research, we obtained SCAR molecular marker of S. glabra and then a pair of specific primers were designed. Using the pair of specific primers, specific products were amplified from genomic DNA of S. glabra, but no specific products were obtained from that of its adulterants. Conclusion: We could authenticate S. glabra and its adulterants effectively with the combination of three molecular markers for establishing a novel method to identify S. glabra and its adulterants, which provides a new idea for the authentication of S. glabra.