Genetic diversity of ten Moroccan populations of Tetraclinis articulata as revealed by Inter Simple Sequence Repeat (ISSR) markers

Tetraclinis articulata (Vahl) Masters is one of Morocco's most important forest species. It is also found occasionally in Malta and Spain, showing significant adaptability to different bio-climatic conditions. However, the species is being affected by anthropogenic fragmentation, logging and neglect from authorities, which could lead to the irretrievable loss of this resource. In this study, the genetic diversity and genetic structure of ten Moroccan populations of T. articulata were assessed. Fifteen Inter-Simple Sequence Repeat (ISSR) markers were used. These generated 271 polymorphic fragments with an average of 18.06 per primer and showed 79.59% of polymorphism. The 129 individuals revealed a high level of genetic diversity (Hs = 0.221; Ht = 0.254) and 85% of genetic variation within populations. However, the genetic differentiation level was low (Gst = 0.13), which is consistent with the lack of correlation between genetic and geographic distances revealed by the Mantel test, resulting in a high level of gene flow (Nm = 3.294). Based on PCoA and neighbour-joining methods, the ten populations clustered under the effect of continental and marine climates. Compared with other conifers, the current genetic diversity and the pattern of T. articulata population structure indicate an important gene pool requiring efficient conservation strategies.