Genetic diversity and population structure of Plantago major (Plantaginaceae) in Iran.
Once only limited to Eurasia, the worldwide distributed Plantago major L. is now considered as invasive. Its significant distributional range in Iran requires molecular scientific efforts to reliably elucidate its genetic diversity and population structure. Therefore, analysis of genetic diversity of 17 different populations of P. major by ISSR markers was carried out and revealed the presence of a relatively high genetic diversity, in which, means of genetic diversity statistics for populations including number of different alleles (Na), number of effective alleles (Ne), Shannon's information index (I) and Nei gene diversity (H) were 1.12, 1.32, 0.271 and 0.184, respectively. Population of Damavand had the maximum Na (1.51) while population from Meshkinshahr indicated superior values for Ne (1.466), I (0.386), H (0.262), and UHe (0.291). Analyzing the genetic diversity distribution by AMOVA exhibited that a major portion of total genetic diversity is within-population (77%), and less among-populations (19%) and among-regions (4%). Neighbor Joining trees display gene flow/shared alleles among studied populations. Populations genetic stratification showed a mixture of two groups with different dominance from northwest to the northeast of Iran. Assessing the genetic structure indicated existence of a relatively strong genetic structure among populations. Mating system, invasiveness characters and seed dispersal are suggested to be effective factors for a high rate of gene flow and simultaneous presence of genetic differentiation among populations of P. major in Iran.