Introduction: Water scarcity and soil salinization are increasingly becoming limiting factors in food production, including olives, a major fruit crop in several parts of the world. Investigating historical olives, which are the last resort for genetic resources, is essential due to their natural resilience to drought and salinity, making them valuable for breeding stress-tolerant cultivars and ensuring sustainable olive production.Methods: In this study, four historic olive cultivars (‘Nabali’, ‘Mehras’, ‘Frantoio’, and ‘Manzanillo’) were investigated under both drought and salinity stresses. These cultivars also preserve local biodiversity, support traditional agriculture, and offer economic opportunities through unique, heritage-based olive oils. Drought and salt stress in olives are assessed through physiological [the ratio of variable to maximum fluorescence (Fv/Fm), relative water content (RWC)], biochemical (proline content), and molecular (stress-responsive genes) analyses to evaluate stress tolerance.Results: Under salinity and drought stress, RWC decreased in all olive cultivars, with drought having the most severe impact. ‘Nabali’ exhibited the highest salinity tolerance, while all cultivars showed similar sensitivity to drought. Proline levels remained stable in ‘Mehras’ but decreased under salinity stress in ‘Frantoio’, ‘Manzanillo’, and ‘Nabali’. Higher proline accumulation under drought suggested better drought tolerance than salinity in these cultivars. Photosynthetic efficiency (Fv/Fm) declined under salinity and drought stress in all cultivars, with drought causing a more significant reduction. ‘Manzanillo’ showed the highest sensitivity to drought, while the other cultivars maintained moderate efficiency under stress. ‘Manzanillo’ and ‘Mehras’ exhibited the highest number of differentially expressed genes (DEGs) under both drought and salinity stress, with ‘Manzanillo’ showing 2,934 DEGs under drought and 664 under salinity stress, while ‘Mehras’ had 2,034 and 2,866 DEGs, respectively. ‘Nabali’ demonstrated the strongest salinity-specific response, with 3,803 DEGs under salinity stress compared to 1,346 under drought. ‘Frantoio’ consistently had the lowest number of DEGs, with 345 under drought and 512 under salinity stress, indicating a more stable transcriptional response. Comparative analyses between drought and salinity conditions revealed significant variations, with ‘Manzanillo’ showing 2,599 unique DEGs under drought relative to salinity stress, while ‘Nabali’ exhibited 2,666 DEGs under salinity stress relative to drought. The major novel upregulated genes under salinity stress were Xyloglucan endotransglucosylase hydrolase (7 fold in ‘Nabali’ and 6.9 fold in ‘Mehras’). The novel drought genes detected in ‘Frantoio’ included Phytosulfokines 3 (4.9 fold), while Allene oxide synthase (6.5 fold) and U-box domain-containing (6.4 fold) were detected in ‘Manzanillo’.Discussion: The data revealed both novel and common stress-specific biomarkers under both salinity and drought stress, which can potentially be utilized in olive breeding and genetic improvement programs to mitigate stress.

The water–energy–food (WEF) nexus is an integrated conceptual tool for achieving sustainable development especially for countries facing limitations in one or more of its three pillars. The approach relies on bringing different stakeholders from the water, food and energy sectors together to collaboratively plan and adopt a holistic approach to resources management. This enables them to address sector-specific issues and develop a comprehensive understanding of the connected sectors leading to better outcomes. However, WEF nexus implementation is currently in its infancy in many countries and stakeholders are in the process of learning how to effectively communicate and collaborate with each other. In this paper, we report the state of the WEF nexus in Jordan, a dry country grappling with water, energy and food production challenges in a changing climate. Stakeholders from line ministries, academics, private sector players and non-state actors were brought together to discuss the status of the WEF nexus and identify challenges that need to be overcome for full realization of the WEF nexus as an operational framework for integrated development at country level. Stakeholders identified 7 cardinal lessons in the process of WEF nexus implementation in Jordan. These are that (i) data/information sharing is vital (ii) WEF nexus requires funding, (iii) collaborations among actors is key, (iv) inclusivity in planning is necessary, (v) clear responsibilities and boundaries among stakeholders are needed, (vi) sustainability and cohesion are a must and (vii) building trust among and within organizations is a primary ingredient for success. A deeper understanding of the interrelated dynamics of these challenges is required to foster the WEF nexus in Jordan as the issues are grave but not insurmountable. It is therefore suggested that deliberate efforts are needed from a technical and policy angle to ensure full operationalization of the WEF nexus approach in Jordan and elsewhere.

Worldwide, Prosopis Genus is widely spread and well known to be of high tolerance to harsh conditions. The P. juliflora and P. cineraria species were introduced to the Mediterranean, while P. farcta is a native one. The genomic structure of the chloroplast of P. juliflora, P. cineraria and P. farcta were targeted in this study. The chloroplast DNA samples were sequenced by genetic analyzer sequencer “Ion S5™ System. The results indicated the size of the genome to be ranged between 162900 bp in P. farcta and 163667 bp in P. cineraria. The full chloroplast of P. juliflora and P. cineraria genome were reported for the first time nationally in Jordan, while globally P. farcta was the first to be analyzed genetically. The present study offers an important portfolio of Prosopis species chloroplast genome analyses, this could help with identification of species and speed up biological and genetic diversity researches.

Ancient olives are considered a major resource of gene pool, adapted across ages to ever changing environments. The ancient ‘Mehras’ olive is the only cultivar inscribed on the UNESCO Representative List of the Intangible Cultural Heritage Of Humanity as recognized for its longevity and historical significance. However, detailed genetic and phenotypic analyses are still missing. Nineteen ‘Mehras’ accessions were collected from northern Jordan and subjected to inter-simple sequence repeat (ISSR) marker analysis and to a set of phenotypic parameters (leaf, fruit, and stone). ISSR analysis revealed similarity values ranging between 0.53 and 1.00, indicating moderate to high genetic diversity. Bayesian clustering and dendrogram analyses identified two major genetic clusters with limited admixture, indicating extended clonal propagation in addition to the transport of planting material. Phenotypic parameters revealed tangible variation among accessions, with major influence of fruit and stone traits followed by leaf traits. Strong correlations were observed between key traits, including fruit width and flesh thickness, while an inverse relationship was observed between flesh and stone percentages. Multivariate analysis further revealed clear separation among investigated accessions. The Mantel test showed a moderate correlation between genetic and phenotypic distances. Spatial analysis suggested weak geographic structuring of diversity, indicating exchange of plant material. ‘Mehras’ olive harbors structured genetic and phenotypic diversity influenced mainly by adaptation and traditional cultivation practices. These findings provide a foundation for conservation, breeding, and sustainable utilization of this ancient and culturally significant cultivar.

Major historic olive tree cultivars around the Mediterranean originate from the Jordan area and possess a proven abiotic stress tolerance; however, they were unexplored from the diversity perspective. Therefore, historic olive tree accessions from three northern regions—Irbid (i), Jerash (J), and Ajloun (A)—were analyzed using DNA molecular markers to identify and study their genetic relationships and genetic structure. DNA molecular markers of inter-simple sequence repeats (ISSR) were used. A total of 3150 data entries (859 present and 2291 absent) were generated with fragment sizes ranging from 350 to 2000 bp. Data entries were evaluated with UPGMA and population genetic structure analysis. The results showed that similarity among the investigated sixty-three accessions ranged from 9% between J14 and i20 up to 100% between ‘J11’ and ‘J12’ and between A8 and A9. The discriminating power values for ISSR_807, ISSR_810, and ISSR_825 were 0.70, 0.61, and 0.83, respectively. A generated dendrogram showed ten major clades, while the genetic structure could resolve four unique genetic pools: one for Irbid, one for Jerash, and two for Ajloun. In addition, analysis of 19 phenotypic parameters covering leaf, fruit, stone, and flesh was able to confirm the molecular data. Phenotypic and ISSR data were analyzed using PCA, cluster, and Mantel tests. ISSR markers showed clear genetic differentiation among groups, whereas phenotypic traits displayed lower variation but a significant correlation with molecular diversity. Promising accessions with either pure or admixture genetic makeup were identified. The resolved genetic structure of the investigated historic olive accessions would open new frontiers for olive breeding and utilization, helping to overcome current production challenges and climate change limitations.