Genetic diversity and population structure in medicinal plant Melissa officinalis L. (Lamiaceae)

Melissa officinalis is an important medicinal plant and is extensively used by locals. This species is growing in different regions of Iran and forms several local populations. There is no information on population genetics or genetic variability of this species from Iran based on SCoT marker. Therefore, we carried out population genetic study of this plant species by analyzing 10 geographical populations. The analysis molecular variance test produced significant genetic difference among the studied populations. Neighbor Joining tree and Principal Coordinates Analysis plot produced similar results. They grouped plants of each population almost in a separate cluster, but also revealed a higher degree of within population genetic variability in many populations. The Mantel test produced significant correlation between genetic distance and geographical distance of the studied populations and the occurrence of isolation by distance in M. officinalis. Discriminating power of the start codon targeted (ScoT) marker analysis identified some ScoT loci with adaptive potentials. This study indicated that a combination of population genetic divergence, genetic drift, limited amount of gene flow and adaptation are acting together in M. officinalis populations. Such data can be used in conservation of this important plant in the country.