Genetic and micromorphological differentiation within Sambacus ebulus (Adoxaceae) suggests divergence of populations from Iran

Sambucus ebulus is mainly distributed in the northern, northwestern and northeastern regions of Iran and is characterized by its perennial growth habit and distinctive long, creeping and branched rhizomes. In this study, genetic diversity of seven populations S. ebulus based on molecular ISSR data and the micromorphology of seeds and leaves of this species in Iran were investigated. Micromorphological examination revealed the anomocytic type of stomata and indicated that the epidermal cells of various S. ebulus populations exhibited irregular cell shapes with anticlinal walls ranging from straight to curved. The seed shape was described as predominantly almond-shaped, and the surface of the seed coat of the studied taxa showed a reticulate pattern. The AMOVA (analysis of molecular variance) test showed that 87% of the total genetic variance was due to differences inter-populations genetic differences, while 13% was due to within-populations genetic variability, indicating a high degree of genetic variation among S. ebulus populations. The discriminating power of ISSR (inter simple sequence repeat) loci as determined by Gst against Nm (the number of migrants) analysis, showed that almost all ISSR loci have an excellent discriminating power. Thus, ISSR markers are efficient in differentiating of the studied S. ebulus populations. The Mantel test presented a significant correlation between genetic and geographic distance. These results suggest that the selected markers for genetic analysis represent different regions of the genome and effectively capture the genetic variation within the studied populations.