Uncovering the Genetic Blueprint of the UAE's National Tree: Genomic Evidence to Guide Prosopis cineraria (L.) Druce Conservation

Abstract

Prosopis cineraria (L.) Druce is a keystone tree species of the arid and semi-arid regions of the West and South Asia, with critical ecological, cultural, and consevation significance. In the United Arab Emirates (UAE) and other regions of the Arabian Peninsula this beneficial tree is called Ghaf. Despite its importance, genomic resources and population-level diversity data for the tree remain limited. Here, we present the first comprehensive population genomics study of Ghaf, based on whole-genome re-sequencing of 204 individual trees collected across the UAE. Following Single Nucleotide Polymorphism (SNP) discovery and stringent filtering, we analyzed 57, 183 high-quality LD-pruned SNPs to assess population structure, diversity, and gene flow. Principal component analysis (PCA), sparse non-negative matrix factorization (sNMF), and discriminant analysis of principal components (DAPC) revealed four well-defined genetic clusters, broadly corresponding to geographic origins. Genetic diversity varied significantly among groups, with observed heterozygosity (Ho), inbreeding coefficients (F), and nucleotide diversity ({pi}) showing strong population-specific trends. Genome-wide Fixation index F ST scans identified multiple highly differentiated genomic regions, enriched for genes involved in stress response, transport, and signaling. Functional enrichment using Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Pfam annotations indicated overrepresentation of protein kinase activity, ATP binding, and hormone signaling pathways. TreeMix analysis revealed gene flow into one of the genetic clusters from both others, suggesting historical admixture and geographic connectivity. To support data interpretation and stakeholder engagement, we developed two web-based tools for interactive visualization of sample geolocation and genetic structure. This work provides foundational insights into the genetic landscape of P. cineraria (L.) Druce, supporting conservation planning and long-term monitoring in the region.