Genetic diversity and population structure of six species of Capparis in Tunisia using AFLP markers

Population Genetic Structure and Biodiversity Conservation of a Relict and Medicinal Subshrub Capparis spinosa in Arid Central Asia

As a Tertiary Tethyan relict, Capparis spinosa is a typical wind-preventing and sand-fixing deciduous subshrub in arid central Asia. Due to its medicinal and energy value, this species is at risk of potential threat from human overexploitation, habitat destruction and resource depletion. In this study, our purpose was to evaluate the conservation strategies of C. spinosa according to its genetic structure characteristics and genetic diversity pattern among 37 natural distributional populations. Based on genomic SNP data generated from dd-RAD sequencing, genetic diversity analysis, principal component analysis, maximum likelihood phylogenetic trees and ADMIXTURE clustering, the significant population structure and differentiation were explored. The results showed the following: (1) Six distinct lineages were identified corresponding to geographic locations, and various levels of genetic diversity existed among the lineages for the natural habitat heterogeneity or human interferences; (2) The lineage divergences were influenced by isolation by distances, vicariance and restricted gene flow under complex topographic and climatic conditions. Finally, for the preservation of the genetic integrity of C. spinosa, we suggest that conservation units should be established corresponding to different geographic groups, and that attention should be paid to isolated and peripheral populations that are experiencing biodiversity loss. Simultaneously, monitoring and reducing anthropogenic disturbances in addition to rationally and sustainably utilizing wild resources would be beneficial to guarantee population resilience and evolutionary potential of this xerophyte in response to future environmental changes.

Genetic relationships among subspecies of Capparis spinosa L. from Tunisia by using ISSR markers

In Tunisia, Capparis spinosa L. is widely distributed in different geographic areas. Although it has been extensively studied morphologically, the phylogenetic relationships by using molecular markers among Capparis taxa are still unclear. The Inter-Simple Sequence Repeats (ISSR) molecular markers were used to assess the genetic relationship of this species cultivated in the North and the South of Tunisia. Fifteen ISSR primers were analyzed to characterize the genetic profiles of 67 different genotypes. The ISSR markers produced 108 bands ranging from 4 (ISSR8) to 11 (IAM12 and ISSR16) with an average of 7.2. The observed heterozygosity ranged from 0.43 to 0.95 for ISSR7 and IAM12, respectively. The Polymorphic Information Content (PIC) ranged from 0.48 at the UBC808 to 0.85 at IAM12 and eight loci could be classified as useful for genetic mapping (PIC > 0.7). The genetic diversity within a population was high and varied according to the subspecies and bioclimatic zones. Both UPGMA (Unweighted Pair Group Method with Arithmetic mean) and PCoA (Principal Coordinate Analysis) analyses showed that populations from each subspecies grouped together. However, the structure analysis generated more groups than the PCoA plot and UPGMA, which revealed the mixed allelic of the species Capparis spinosa in Tunisia.

Phytochemical and Pharmacological Properties of Capparis spinosa as a Medicinal Plant

Over the past decades, there has been increasing attention on polyphenol-rich foods including fruits and vegetables on human health. Polyphenols have been shown to possess some potential beneficial effects on human health and they are widely found in foods consumed by populations worldwide. Capparis spinosa (C. spinosa) is an important source of different secondary metabolites of interest to humankind. The traditional therapeutic applications of C. spinosa have been reported in Ancient Romans. Numerous bioactive phytochemical constituents have been isolated and identified from different parts (aerial parts, roots and seeds) of C. spinosa which are responsible alone or in combination for its various pharmacological activities. Therefore, this paper is a review of publications on the phytochemical and pharmacological properties of C. spinosa. There is insufficient evidence to suggest that C. spinosa or its extracts are able to improve the biomarkers of cardiovascular disease and diabetes. However, these studies used different parts of C. spinosa plant, methods of preparation and types of solvents, which cause the evaluation of activity of C. spinosa difficult and involve quite heterogeneous data. There is also evidence, although limited, to suggest benefits of C. spinosa in improving human health. Therefore, the relationship between C. spinosa and improved human health outcomes requires further study.