Elucidation of Genetic Markers for the Essential Oils Quantity in Mentha Plants F-AFLP

Medicinal plants are an essential source of therapeutic ingredients, being also the basis of traditional or original healing systems. Many medicinal plants belong to the family Lamiaceae. The Mint is the common name of about 25 perennial species of the genus Mentha. The essential oils of the Mentha species and their extracts are well documented and possess antimicrobial, antifungal, antiviral, pesticide, and antioxidant properties. The current study aimed to collect and genotype mint species from different sources using fluorescently labeled AFLP technique to asses the genetic variability and elucidate high-resolution genetic markers related to oil content and/or oil quantity. A total of 11 mint samples were analyzed using AFLP technique; among the three primer pair combinations showed number of peaks ranged between 49 to 117, with a minimum band size in base pair of 50 bp to 661 bp. The overall mean of number of bands per individual is 99, while the total number of polymorphic loci is 254. Based on the maximum likelihood hybrid index method, two samples were found misclassified or possibly hybrids. Out of the 254 polymorphic bands, 16 were found specific to the high oil-content group [A] compared to 95 bands that were specific for the low oil-content group [B]. In group A, two bands, P1.23 and P2.28, were found fixed as present in group A while absent from group B, the bands were scored from the primer pairs 1 and 2 of 297 and 140 bp, respectively; and considered as positive markers to high-oil content. However, no negative marker was found. When the two possible hybrids were inspected, the positive marker number 1 [PP1.23] was found consistent and absents in the two samples, which increase its validity as a positive marker for high-oil content, while was not the same case for the second marker. Comparing both the whole dataset and the selected markers using AMOVA and PCoA, the elucidated markers should higher genetic differentiation among the studied groups than the whole dataset. The selected markers can be applied for marker-assistant selection breeding program and early preselection of high-oil content samples for future studies related to the oil content in Mentha sp.