Abstract

Mentha (Lamiaceae) is a medicinal, aromatic plant known globally as mint. Madinah mint (Saudi Arabia) is grown and consumed as a drink, flavor for tea, spice for food, and a home remedy. In this report, matK, rbcL rpoC1, and ycf5 genes, the intergenic region trnA-trnH from the plastid genome, along with the two nuclear loci internal transcribed spacers (ITS1 and ITS2) were tested as DNA barcodes for Madinah mint. DNA was extracted, polymerase chain reaction was amplified using specific primers, and the products were sequenced. The partial sequences of the matK gene from Madinah mint are identical to those from Mentha piperita, while sequences of the rbcL gene were identical to Mentha canadensis and Mentha spicata discriminating this species from M. piperita. Phylogenetic analysis using ITS1 or ITS2 showed that Madinah mint is a basic taxon to M. spicata and M. canadensis. Phylogenetic analysis based on a combination of ITS1 and ITS2 sequences showed that Madinah mint is ancestral to other Mentha species. The same analysis using rbcL gene sequences again put Madinah mint as an ancestor of both M. spicata and M. canadensis as well as Mentha suaveolens, which might suggest that they have shared the same origin of the maternally inherited plastid genome.

Key words: Mentha; Medina; DNA barcode; plastid