Genetic relationships of Iranian endemic mint species, Mentha mozaffariani Jamzad and some other mint species revealed by ISSR markers

Mint species (Mentha sp.) are important vegetables with medicinal and economic characteristics. In this study, the genetic relationships of 34 accessions of 5 mint species including Mentha spicata, Mentha longifolia, Mentha piperita, Mentha aquatica, and Mentha mozaffarianii Jamzad were evaluated using Inter-Simple Sequence Repeat (ISSR) markers, followed by the analysis of the polymerase chain reaction (PCR) products on a high-resolution acrylamide gel. ISSR primers yielded 74 clear and reproducible bands, of which 50 bands were polymorph (65.28%), with a minimum of 7 ((TG)₈G) and a maximum of 17 ((GA)₈YC) bands per primer. Polymorphism information content (PIC) for each primer varied from 0.37 to 0.46 with an average of 0.41. The marker index referred to (GA)₈YC primer as the most efficient compared to others. The analysis of the molecular variance (AMOVA) at the species level showed that variation within the species (75%) exhibits greater partitioning than the variation among species (15%). The cluster analysis performed was based on Nei’s genetic distances using the unweighted pair group method with arithmetic mean (UPGMA) method. At the accession level, all 34 accessions were separated into 3 main clusters. The cluster analysis at the species level placed 3 species including M. aquatica, M. longifolia, and M. spicata in one common group. Based on the cluster analysis, the M. mozaffarianii Jamzad, as an Iranian species, was placed in Mentha section, closer to other species, when compared to M. piperita. The results indicated that ISSR markers alongside a high-resolution electrophoresis can be truly helpful in visualizing the diversity among different accessions of one species.