Genetic diversity and population structuring of Pistacia lentiscus L. across Mediterranean region

Abstract

Pistacia lentiscus L., the mastic tree, is an evergreen shrub distributed across the entire Mediterranean Basin. This species, known for millennia for its medicinal, food and cosmetic value is currently threatened by overexploitation and climate change. To help prioritize conservation actions, we studied its genetic diversity using seventy four Mediterranean accessions and seven microsatellite loci. Genomic DNA was extracted from mastic tree leaves. Allelic frequency and population structure estimates were calculated as well as the relationship between studied populations. The observed heterozygosity (Ho) and expected heterozygosity (He) ranged from 0.493 to 0.788 and 0.518 to 0.781 respectively. Shannon’s Information Index (I) ranged from 0.858 to 1.819 with a mean value of 1.420. The mean fixation index (Fst) value was estimated to 0.124. AMOVA analysis showed that only 7% of the variance existed among populations. In addition, the STRUCTURE analysis showed a clear distinction between the eastern and the western Mediterranean populations when the number of clusters (K) was set at 2. The study of genetic diversity of the Mediterranean P. lentiscus is of interest for conservation of genetic resources and it contributed to the understanding of the evolutionary history of this species.