Genetic diversity of the Balkan endemics Moehringia jankaе Griseb. ex Janka and Moehringia grisebachii Janka (Caryophyllaceae) from Bulgaria using ISSR markers

Eleven populations of the endangered plant Moehringia jankaе and twenty-eight of the rare plant Moehringia grisebachii were collected across its natural range from Bulgaria. Their genetic diversity was investigated through fifteen selected Inter Simple Sequence Repeats (ISSR) primers. The ISSR primers produced a total of 285 bands, of which 275 were polymorphic and 10 – monomorphic. Capability of the primers was assessed through the high mean values for the polymorphic information content (0.78), effective multiplex ratio (14.73), resolving power (27.90) and marker index (11.36). Based on the obtained mean values of the molecular data the species M. grisebachii (effective number of alleles = 1.39, Shannon’s information index = 0.38, expected heterozygosity = 0.24, Nei's genetic diversity = 0.25, gene flow= 0.65) demonstrated higher genetic diversity than the species M. jankaе (effective number of alleles = 1.28, Shannon’s information index = 0.26, expected heterozygosity = 0.17, Nei's genetic diversity = 0.23, gene flow = 0.52). These results were supported by Analysis of molecular variance (AMOVA), showing higher variability within populations of M. jankaе (90%) and M. grisebachii (62%), than among populations - 10% and 38%, respectively, and 25% among both species. Neighbor joining and principal coordinate analysis (PCoA) grouped the thirty-nine studied populations by species and region of spread. The data are applicable in conservation programs for protecting and keeping of both species. The registered genetic similarity between the populations of the two species (from Eastern Balkan Range) does not exclude the possibility of hybridization between their natural populations.