Genetic diversity and differentiation of the endangered tree Elaeagnus mollis Diels (Elaeagnus L.) as revealed by Simple Sequence Repeat (SSR) Markers

Abstract

Elaeagnus mollis Diels (Elaeagnus L.) is an economically and ecologically important but endangered tree in China. Understanding its genetic diversity is essential for its conservation and sustainable utilization. Simple Sequence Repeat (SSR) markers were used to assess the genetic diversity and differentiation in 7 wild populations of E. mollis. Ten primer pairs yielded a total of 163 alleles. Allelic richness (Ar = 12.3), Nei’s gene diversity (H = 0.69) and observed heterozygosity (HO = 0.63) indicated high species-level genetic diversity. Analysis of molecular variance (AMOVA) revealed limited genetic differentiation, with 16.8% of total genetic variability partitioned among populations. Genetic distances were not significantly associated with geographic distances (Mantel test, r = 0.3085, P = 0.1258), indicating disconformity to the isolation-by-distance model. UPGMA cluster analyses and Bayesian clustering supported the grouping of the populations into 2 groups. The present genetic structure of E. mollis may be explained by its life-history traits, breeding system, unique biological traits and anthropogenic disturbance. Considering the high intraspecific genetic diversity, the endangerment of E. mollis has more likely resulted from anthropologic effects. A proper conservation strategy is proposed for this plant.