DNA bacording of Verbenaceae medicinal plant by using ITS2 and psbA-trnH region

Objective: To evaluate the ability of several hotspot candidate sequence of DNA barcodes for identifying medicinal plant species in Verbenaceae.

Methods: Using universal primers, three chloroplast sequences, psbA-trnH, rbcL, matK, two nuclear ribosomal DNA ITS2 and ITS were amplified and sequenced. PCR amplification and sequencing efficiency, intra- and inter-specific variation, barcoding gap and identification efficiency (with BLAST 1 and Nearest Distance methods) were used to evaluate these loci.

Results: The rate of successful amplification using matK was too low to further analyze, and the rate of successful amplification and sequencing using psbA-trnH, ITS, and ITS2 and rbcL sequence was 83.6%, 83.6%, 96.4%, 98.2%, respectively. The rate of successful identification using psbA-trnH, ITS, and ITS2 was 100% at the species level except that rbcL was 77.8%, 75.9% for 55 samples belonging to 32 species, but ITS2 did better in intra- and inter-specific variation, barcoding gap than the other loci. The rate of successful identification of ITS2 was 89.5%, 87.6% even when joining the date of 165 samples from GenBank.

Conclusions: It proposes that the combination of ITS2 and psbA-trnH senquence is promising for the identification of the species in Verbenaceae.