Prunus Species Diversity, Structure and Phylogenetic Studies Assessed by Chloroplastic Microsatellite Markers

The genus Prunus is among the main species cultivated in Tunisia, due to its economic importance. In this study, genetic diversity and relationships among Tunisian Prunus species was explored using six specific SSR chloroplastic primers (cpSSR) of Rosaceae. The parameters of polymorphism were estimated and showed 5.831 alleles per locus, among them, 1.315 were effective alleles, giving a Shannon’s information index of 0.323. Twelve haplotypes were shared by more than one accession, while 55 haplotypes were accession-specific, confirming the effectiveness of cpSSR as good markers for molecular characterization and identification of Prunus species. Furthermore, the important haplotype diversity proved the allelic singularity of the Tunisian genotypes, considered as a valuable gene pool repository for future breeding programs. Moreover, the results obtained highlighted the ancient origin of the Tunisian Prunus genotypes. The UPGMA dendrogram, the model based Bayesian clustering, PCA analysis and Nm values are clearly consistent with a genetic structuring and showed a high level of differentiation within the genus. Although, the classification of Prunus genus has been controversial issue, our results showed that chloroplastic genome may supply information regarding the evolutionary history of members of Prunus genus. To conclude, this work joins to other studies to demonstrate the effective power of single- parent organelle markers for molecular characterization and population genetic studies.