Wild Olive Research Articles

Genome-Wide Identification and Characterization Thaumatin-like Protein (TLP) Genes in Wild Olive (Olea europaea var. sylvestris)

The wild olive tree (Olea europaea var. sylvestris) is the ancestor of all olive varieties, displaying remarkable adaptability to diverse climatic conditions and soil types. This iconic tree of the Mediterranean Basin stands out for its ability to withstand environmental stresses, such as water scarcity and temperature variations, playing a crucial role in the ecology, economy, and culture of the region. In this study, 42 TLP genes were characterized in the wild olive tree, distributed across 14 chromosomes and nine scaffolds. In silico analysis revealed the presence of domains associated with antifungal activity in some sequences, indicating their potential role in pathogen resistance. The structural diversity of OeTLP genes was explored through multiple alignments, conserved motifs and phenetic analysis. Correlation was observed between phenetic diversity, genetic structure, and motif patterns, suggesting different functions among OeTLP groups. Additionally, the distribution of exons and introns in the pheneticc tree provided further insights into the evolution of these genes. Comparative modeling of OeTLPs unveiled three-dimensional models with good structural quality and distinctive surface charge characteristics. This study provides a comprehensive understanding of the physicochemical, structural, and phenetic features of TLP genes in Wild Olive, contributing to knowledge about this species' response to environmental stresses and pathogens.

The biogeographic patterns of the olive fly and its primary symbiont Candidatus Erwinia dacicola across the distribution area of the olive tree.

The olive fly, Bactrocera oleae (Rossi, 1790), is the major insect pest of olives attacking both cultivated and wild olive. Bactrocera oleae carries a primary and vertically transmitted symbiont, the bacterium Candidatus Erwinia dacicola. As any primary symbiont, it plays an important role in the reproduction and lifespan of the fly. The genetic 16S rRNA diversity of the primary symbiont and the mitochondrial haplotype variation of the insect host were simultaneously examined in 54 olive fly populations. The aim was to unravel the biogeographic patterns of this economically relevant host-bacteria interaction across a wide distribution area. Three symbiont haplotypes were identified. The primary symbiont showed a lower haplotype diversity than that of its host, a characteristic indicative of a long-term interaction. A significant genetic and geographic association between host and primary symbiont was observed, with an East-West genetic differentiation pattern in the Mediterranean basin, coinciding with the historical genetic distribution of the olive tree. The study shows promise, informing and aiding the development of future tools for the control of the olive fly.

Extra Virgin Olive Oil's Main Components' Antioxidant Activity and in Silico Effect on AKT1.

The study compared the chemical composition of various olive oils from the northern Algerian province of Bejaia. The research focused on the antioxidant activities of the oil's main constituents and their ability to inhibit the AKT1 protein, which is implicated in the development of colorectal cancer. The findings revealed that all of the examined oils fell within the extra virgin olive oil (EVOO) category and exhibited a high oleic acid content, particularly for samples from wild olives. These oils include high amount of ligstroside and oleocanthal, two important phenolic compounds. Wild olive oils stand out from cultivated ones due to their higher bitterness index. In addition, these oils have the highest concentrations of α-tocopherols and the best oxidative stability. Olive oil extracts demonstrated their antioxidant properties by neutralizing DPPH and ABTS radicals and converting ferric ions (Fe3+) to ferrous ions (Fe2+) for FRAP assay. Molecular docking was applied to assess the interaction between the main compounds identified in the analyzed olive oils and the human AKT1 protein, which is involved in the genesis of colorectal cancer. The findings revealed that lutein, oleuropein aglycone, and ligstroside aglycone had the highest binding affinity for the AKT1 protein. The present study could provide the theoretical foundation for further research on the interaction between AKT1 protein and EVOO compounds.

Comparative analysis of cultivated and wild olive genotypes to salinity and drought stress.

The Mediterranean region's harsh conditions, characterized by low rainfall, high solar radiation, and elevated temperatures, pose challenges for vegetation, particularly in the face of climate change. Cultivated olive (Olea europaea subsp. europaea var. europaea) holds historical and economic significance as one of the oldest crops in the Mediterranean. Due to their high germplasm diversity and greater flowering abundance compared to the offspring of cultivated olives, wild olives (Olea europaea subsp. europaea var. sylvestris) could be utilized for selecting new olive cultivars capable of adapting to a changing climate. This research aimed to compare the effects of salt and drought stress on wild and cultivated genotypes by analyzing morphological, physiological, and biochemical parameters. Results showed that shoot length, shoot dry mass, and leaf area are key drought stress indicators in wild olive trees. The results indicated the olive trees more susceptible to salinity stress had lower Na+ and Cl- concentrations in their leaves and took longer to stabilize salt ion levels. Decreased K+ content in roots across all treatments indicated a general stress response. The uptake of Ca2+ appears to be the most energy-efficient response of olive trees to short-term salinity and drought. In contrast to proline and malondialdehyde, trends in superoxide dismutase activity suggest that it is a reliable indicator of salinity and drought stress. Regarding olive adaptability to salinity stress, promising results obtained with two wild olive genotypes merit their further physiological study.

The Status and Distributions of the Wild Olive (Olea europaea subsp. europaea var. sylvestris) in Muğla Province and Its Islands under Global Climate Change

The Status and Distributions of the Wild Olive (Olea europaea subsp. europaea var. sylvestris) in Muğla Province and Its Islands under Global Climate Change

Environment-dependent and intraspecific variations in leaf and size traits of a native wild olive (Olea europaea L.) along an aridity gradient in Morocco: a functional perspective

Environment-dependent and intraspecific variations in leaf and size traits of a native wild olive (Olea europaea L.) along an aridity gradient in Morocco: a functional perspective

European Xylella fastidiosa Strains Can Cause Symptoms in Blueberry.

Strains of the bacterial pathogen Xylella fastidiosa subspecies multiplex (Xfm) and pauca (Xfp) isolated from symptomatic almond and olive plants in Spain and Italy were used in this study. Because of the risk of host jump and considering the importance of southern highbush blueberry production in Spain, we tested a small set of these strains for their potential to infect and cause disease symptoms in blueberries under greenhouse experiments. Xfm IVIA5901 (isolated from almonds in Alicante, Spain) caused symptoms similar to those caused by Xfm AlmaEm3 (isolated from blueberries in Georgia, U.S.A., and used as a reference strain capable of inducing severe symptoms in blueberry). Nevertheless, bacterial populations of Xfm IVIA5901 in planta were significantly lower than those of Xfm AlmaEm3. Xfm ESVL (isolated from almonds, Alicante, Spain) and Xfp XYL1961/18 (isolated from olives, Ibiza Island, Spain) caused limited symptoms, while Xfm XYL466/19 (isolated from wild olives, Mallorca Island, Spain) and Xfm XF3348 (isolated from almonds, Mallorca Island, Spain) and Xfp De Donno (isolated from olives, Puglia, Italy, and representative of the devastating olive quick decline syndrome) did not cause symptoms nor colonize blueberries. This study suggests that certain strains already found in Europe could infect blueberry if conditions conducive for a host jump in this region are met, such as proximity of blueberries to other infected hosts and presence of insect vectors that feed on these crops. Surveys on the presence of X. fastidiosa in blueberries in Spain and other European countries are needed to anticipate possible issues.

Genomic and transcriptomic analyses highlight evolutionary and functional characteristics of WRKY genes in Asterids

WRKY transcription factors regulate development, dormancy, germination, senescence, and reactions to abiotic and biotic stress. Asterids, a major group of eudicots, are commercially and pharmacologically important. However, large-scale WRKY gene family analyses in Asterids are lacking. We performed genome-wide re-annotation and downstream analyses of WRKY genes in nine Asterid species in addition to Arabidopsis thaliana and Beta vulgaris. We identified a total of 1,013 WRKY genes, 91 of which were newly annotated in our analysis. These were divided into six subgroups based on domain structure, phylogeny, and motif composition. Duplication analysis revealed increased copy numbers of WRKY genes belonging to specific subgroups in Helianthus annuus (sunflower), Actinidia chinensis (kiwifruit), and Olea europaea var. sylvestris (wild olive). Both H. annuus and A. chinensis displayed recent duplications of the WRKY gene after their divergence, whereas O. europaea var. sylvestris showed ancient duplication of WRKY genes. Transcriptome analyses suggested the potential function of WRKY genes in responses to abiotic and biotic stresses in H. annuus and A. chinensis, respectively. Our data shed light on the evolutionary and functional characteristics of WRKY genes, especially among Asterid plant species.

Greenly synthesized zinc oxide nanoparticles: An efficient, cost-effective catalyst for dehydrogenation of formic acid and with improved antioxidant and phyto-toxic properties

Formic acid (FA) dehydrogenation is of particular industrial interest as a source of alternative fuels such as H2. However, the development of economical, highly efficient, and selective catalysts for this reaction is a challenging task. Most highly selective catalysts for the conversion of formic acid (FA)/sodium formate (SF) system into hydrogen are based on precious noble metals. Rendering their large-scale utilization more cumbersome and expensive. Therefore, it is of utmost importance to explore a facile and cost-effective strategy for the fabrication of a simple structured solid nano-catalyst with outstanding performance and selectivity for H2 generation without CO evolution from the FA/SF system. In the current study, a phenolic-enriched extract of wild olive leaves was employed for the synthesis of ZnO nanoparticles (ZnO@WOLE-NPs). TEM analysis revealed that the size of ZnO@WOLE nanoparticles was about33 nm. Zeta potential evaluation (38.39 ± 1.32 mV) demonstrated the significant stability of the nanoparticles. XRD analysis provided insights into the formation of hexagonal wurtzite phase ZnO nanoparticles. The reaction conditions were optimized. These resulting ZnO@WOLE-NPs showed extraordinarily high catalytic performance and about 80 % selectivity for H2 generation from the FA/SF system at 50 °C. A turn over frequency and activation energy values for dehydrogenation of FA were noted as 1519 h−1 and 32.1 kJ mol−1, respectively. The kinetics and thermodynamics of FA dehydrogenation were also determined. Furthermore, ZnO@WOLE-NPs exhibited potent antioxidant activity against hydroxyl, DPPH, superoxide, and peroxide radicals. Moreover, the synthesized nanoparticles demonstrated the highest seed germination of Okra seed at a concentration of 1.25 µg mL−1. Whereas, the highest shoot length and root length were observed at the concentration of 1 µg mL−1.

Genome-wide Identification of PMEI Genes in Wild Olives (Olea europaea sylvestris L.) by Bioinformatic Analysis

In the present study, 47 PMEI type 1 genes and 57 PMEI type 2 genes were identified with bioinformatic analysis. The PMEI genes were localized separately on chromosomes 1, 2, 3, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 20, 21 and 22, but mainly at the level of the scaffold. The biological functions of the PMEI type 1 genes were found to be in the areas of biological regulation, metabolism and cellular functions. Their cellular localization appears to be associated with cell parts. For the PMEI type 2 genes, the biological functions were determined as biological regulation, metabolic and cellular functions. A total of 393 Arabidopsis miRNAs targeting 47 olive PMEI type 1 genes were identified. Two specific miRNAs targeting the OePMEI1-07 gene were found (ath-miR8168 and ath-miR774b-5p). For the PMEI type 2 genes, 269 Arabidopsis miRNAs were found, including 14 specific miRNAs targeting OPMEI2-02, OPMEI2-03, OPMEI2-27, OPMEI2-28, OPMEI2-29, OPMEI2-30, OPMEI2-40 and OPMEI2-54. These results suggest that PMEI genes in olives may not only play a role in cell development, germ cell formation and plant growth, but also play an important role in abiotic and biotic stress conditions in the olive.

Elucidating the genetic diversity in wild olive (Olea europaea L. subps. oleaster) genotypes from the Mesopotamia region with multivariate analyses

Elucidating the genetic diversity in wild olive (Olea europaea L. subps. oleaster) genotypes from the Mesopotamia region with multivariate analyses

A Comparative Study of Oleuropein Extraction from Wild Olive Leaves (Olea europea subsp. oleaster, Hoffmanns. & Link), Its Gastrointestinal Stability, and Biological Potential

Olive leaves are the richest source of phenolic compounds, particularly oleuropein, which has many beneficial effects on human health. This study compares the effect of three extraction techniques: ultrasonic-solvent extraction, microwave-assisted extraction, and supercritical CO2 extraction of freeze-dried wild olive leaves (Olea europea subps. oleaster, Hoffmanns. & Link) on oleuropein concentration in obtained extracts. The extract with the highest concentration of oleuropein was obtained after low-frequency ultrasound solvent extraction (WOLE-S) (71.97 µg/mL). Oleuropein from that extract showed low stability after simulated gastric digestion with human gastric juices (35.66%) and high stability after 60 min of intestinal phase (65.97%). The highest antiproliferative activity of WOLE-S and pure oleuropein was detected against T24 cancer cells. The antiproliferative activity of WOLE-S against MD-MBA-123, A549, and A1235 cells was moderate, while the activity of oleuropein was high. WOLE-S significantly down-regulated the expression of IL-6 in A549 cells, indicating a possible anti-inflammatory effect in lung cancer cells. The expression of IL-8 was slightly reduced by treating the cells with WOLE-S, while the expression of IL-10 was not altered by the treatment with WOLE-S or oleuropein.

Extracellular vesicles mirror the beneficial effect of wild olive (acebuche) oil in hypertensive‐like retinal pigment epithelial cells

Aims/Purpose: Arterial hypertension (AH) leads to oxidative and inflammatory imbalance triggering hypertensive organ damage via different pathways. Oil extracted from the wild olive tree (acebuche, ACE) has previously shown antioxidant and anti‐inflammatory properties against hypertensive ocular damage when regularly consumed in the diet1,2. We therefore speculate that circulating extracellular vesicles (EVs) isolated from ACE oil‐fed animals might play a role in modulating pathological mechanisms surrounding AH‐related ocular diseases, including oxidative stress, migration and angiogenesis processes.Methods: Retinal pigment epithelium (ARPE‐19) cells mimicking a hypertensive phenotype induced by incubation with angiotensin II (AngII) were treated with EVs obtained from mice fed ACE oil or a reference extra virgin olive oil (EVOO). The 2′,7′dichlorodihydrofluorescein diacetate (DCFHDA) assay was used to estimate intracellular levels of reactive oxygen species (ROS). Furthermore, kinetic parameters for L‐arginine (L‐Arg) transport and the expression of L‐Arg transporter (CAT‐1) were also analysed. The wound‐healing assay was used to determine the anti‐migratory properties of ACE oil‐derived EVs, and the ability of EVs to modulate angiogenesis was assessed in aortic rings.Results: Both ACE oil‐ and EVOO‐related EVs were able to reduce ROS production in ARPE‐19 cells. The normalization of intracellular redox status by EVs might be exerted through modulation of L‐Arg uptake and CAT‐1 expression. Anti‐migratory and anti‐angiogenesis properties were also displayed by oil‐derived EVs, suggesting their potential benefit in the setting of neovascular ocular diseases.Conclusions: This is the first report to highlight the retinoprotective effects of EVs isolated from the plasma of animals subjected to ACE oil‐ and EVOO‐enriched diets against pathological events related to ocular diseases.

Antioxidant insights of wild olive (acebuche) oil ophthalmic nanoemulsions against arterial hypertension

Aims/Purpose: Many systemic and ocular disturbances are closely related to oxidative stress, including hypertensive eye diseases. In this context, the oral administration of wild olive oil, also known as acebuche (ACE) oil (Olea europaea var. sylvestris), proved to modulate local production of reactive oxygen species (ROS) by the enzyme nicotinamide adenine dinucleotide phosphate (NADPH) oxidase1. Here we aimed to develop an ophthalmic formulation based on ACE oil as a localized therapy against oxidative damage associated with arterial hypertension (AH).Methods: Nanoemulsions (NEs) of ACE oil were successfully produced, characterized, and evaluated in vivo in terms of efficacy. The antioxidant properties of these NEs were tested in mice with AH induced via administration of Nω‐nitro‐L‐arginine‐methyl‐ester (L‐NAME), which underwent intravitreal or topical ophthalmic treatment with ACE oil NEs. At the end of the treatments, a histological analysis of the cornea and retina was performed together with an evaluation of the activity/expression of NADPH oxidase in these ocular tissues.Results: Adequate ophthalmic formulations were designed to present the features for ophthalmic administration, including a nanometre size (below 200 nm), moderate negative ZP, adequate osmolality and pH, among others. Histological analysis indicated that NEs reduced hypertension‐dependent morphological alterations in the cornea and retina. Furthermore, the evaluation of the activity and expression of NADPH oxidase suggest a noticeable antioxidant effect of NEs through downregulation of NOX1, NOX2 and NOX4 isoforms and counteracting excess ROS production in the hypertensive eye.Conclusions: Topical administration, via intravitreal or drop instillation, of an ophthalmic formulation based on ACE oil NEs might show promise against ocular pathologies related to AH. Interestingly, this therapeutical approach provided better outcomes compared to long‐term dietary administration of the oil, both in terms of cumulative dose and treatment time required.

A Preliminary Study on Morphological Characters of Genetic Diversity of The Oldest Libyan Wild Olive Trees at The Jabal Al-Akhdar Region

A Preliminary Study on Morphological Characters of Genetic Diversity of The Oldest Libyan Wild Olive Trees at The Jabal Al-Akhdar Region

The Functional and Rheological Properties the Mesocarp Layer of the Oleaster (Elaeagnus angustifolia L.) grown in Karaman

The oleaster (Elaeagnus angustifolia L.), also known as wild olive, is a small fruit with three parts: the outer peel or exocarp layer, the edible part or mesocarp layer, and the inner seed or endocarp layer. The mesocarp layer is rich in essential vitamins and has great potential for use in various food products. The flour made from the mesocarp layer has a moisture content of 8.99%, an ash content of 2.66%, a fat content of 0.55%, a protein content of 5.99%, a crude fiber content of 3.32%, and a total dietary fiber (TDF) content of 26.36%. The TDF content is divided into insoluble dietary fiber (IDF) and soluble dietary fiber (SDF), which are 21.35% and 5.01%, respectively. The flour has color values of L*: 75.14, a*: 2.86, b*: 23.87, and a water activity value of 0.314. The water solubility, water absorption, and oil absorption are 67.33%, 4.91 g water/g sample, and 2.26 g oil/g sample, respectively. Additionally, the mesocarp layer contains minerals such as Mg, P, K, Ca, Fe, and Na. The mesocarp layer significantly affected the thermomechanical properties of wheat flour. As the substitution level of the mesocarp layer increased from 10 to 30%, the water absorption capacity, dough development time and stability time of the wheat dough significantly decreased. Specifically, the water absorption capacity dropped from 53.5% to 47%, dough development time reduced from 1.10 to 0.75 min, and stability time decreased from 8.90 to 2.25 min. Substituting a mesocarp layer in wheat flour can significantly improve product shelf-life due to slower retrogradation. The mesocarp layer is an functional ingredient in the food industry.

Assessing the economic, social and environmental potential of wild and domesticated olive growing options in a far Western District of Nepal

CONTEXTClimate change and extreme weather events undermine smallholder household food and income security in many rural areas of developing countries. Nature-based solutions and the use of climate resilient and nutrient dense Neglected and Underutilized Species into the local farming system have been claimed to sustainably help farmers adapt to climate change and to manage risk more effectively. OBJECTIVEThis paper investigated the potential implementation of three options based on the collective cultivation and management of olive groves and wild forests for production purposes in a mountain region of Nepal. The analysis was aimed at assessing the potential benefits of such strategy in comparison with the status-quo. METHODSThe study conducted an ex-ante simulation exercise for evaluating three options: 1) 1500 ha of new and restored wild forests; 2) 500 ha of olive groves; and 3) A combination of option 1 and 2. We calculated the financial, economic, social, and environmental costs and benefits of such options using agricultural and economic data collected from representative households identified from a sample of 31 small, 9 medium, and 3 large farm households. To conduct the economic, social and environmental analysis (ESE), we calculated the Social Return on Investment and we integrated it into the economic analysis. Then we compared the results to assess which was the most profitable option. RESULTS AND CONCLUSIONSThe results of the analysis showed that all three proposed options are stable with an Internal Rate of Return always above 27% with values over 100%. The greatest increase in terms of NPV is observed when shifting from the financial to the ESE analysis in options 1, 2, and 3 (+397.5%, +132.0%, +187.2% respectively) as the benefits increase more than the costs. The results further suggested that the integrated option is the most profitable one also in terms of labour generation. Indeed, we observed a substantial increase in the Return to Labour indicator especially in the ESE analysis (from 1.9 in the financial analysis to 2.8 in the economic analysis to 6.0 in the ESE analysis). SIGNIFICANCEThis study provides evidence of the potential that similar strategies based on the use of local resources and species, if properly designed, implemented and managed, may have to restore the ecosystem and enhance the livelihoods of local communities. The most innovative element of this study is the proposed ESE analysis, which takes into account the social and environmental dimension besides the economic one.

Exploring the synergistic potential of wild nettle and olive oil: bioactive compounds, antioxidant capacity, and antibacterial properties

ABSTRACT This study delved into the incorporation of wild nettle (Urtica dioica L.) leaves powder with virgin olive oil, exploring its potential to enhance nutritional value and health benefits. The antioxidant, antibacterial, and mineral-enrichment attributes of the resultant nettle-infused olive oil were investigated. Phenolic composition analysis revealed that an optimal maceration time of 30–40 minutes leads to maximal phenolic and flavonoid contents (57.66 mg GAE/100 g and 67.18 mg QE/100 g, respectively). The infused oil demonstrated superior radical scavenging activity (DPPH and ABTS assays) compared to virgin olive oil. Notably, nettle infusion significantly elevates zinc (10.12 mg/kg) and iron (13.85 mg/kg) contents. Antibacterial assays exhibited enhanced inhibition diameters and lower MIC and MBC values for nettle-infused oil against various bacterial strains. The study’s findings underscore the potential of nettle infusion to enhance the nutritional and functional attributes of olive oil, holding promise for novel culinary and health applications.

Exploring the Potential of Wild Olive (Acebuche) Oil as a Pharm-Food to Prevent Ocular Hypertension and Fibrotic Events in the Retina of Hypertensive Mice.

Our laboratoryhas previously described the antioxidant and anti-inflammatory potential of a wild olive (acebuche, ACE) oil against hypertension-associated vascular retinopathies. The current study aims to analyze the antifibrotic effect of ACE oil on the retina of hypertensive mice. Mice are rendered hypertensive by administration of NG-nitro-L-arginine-methyl-ester (L-NAME) and simultaneously subjected to dietary supplementation with ACE oil or a reference extra virgin olive oil (EVOO). Intraocular pressure (IOP) is measured by rebound tonometry, and retinal vasculature/layers are analyzed by fundus fluorescein angiography and optical coherence tomography. Different fibrosis-related parameters are analyzed in the retina and choroid of normotensive and hypertensive mice with or without oil supplementation. Besides preventing the alterations found in hypertensive animals, including increased IOP, reduced fluorescein signal, and altered retinal layer thickness, the ACE oil-enriched diet improves collagen metabolism by regulating the expression of major fibrotic process modulators (matrix metalloproteinases, tissue inhibitors of metalloproteinases, connective tissue growth factor, and transforming growth factor beta family). Regular consumption of EVOO and ACE oil (with better outcomes in the latter) might help reduce abnormally high IOP values in the context of hypertension-related retinal damage, with significant reduction in the surrounding fibrotic process.

Production of Polyurethane Elastomers from Ximenia americana L (Wild Olive) Seed Oil and Diisocyanates

Seed oils readily undergo derivatization by alcoholysis to yield biodegradable polyols and Ximenia americana plant from the family of Olacaeae has oily seeds. Hence, the objective of this paper is to assess the production of polyurethane elastomers from Ximenia americana L (Wild Olive) Seed Oil with diisocyanates, namely, hexamethylene diisocyanate (HDI), toluene diisocyanate (TDI) and 4,4’-methylene diphenyl diisocyanate (MDI) respectively using standard procedure and characterized by Fourier-Transform Infrared Spectroscopy (FTIR), Instron Tensile Testing Machine and Thermogravimetric Analyzer (TGA). The tensile strength and tensile modulus for HDI-based polyurethane elastomers, 5.83±0.15 and 3.95±0.07 MPa respectively are higher than the corresponding ones for TDI- and MDI-based polymers. This is consistent with the highest crosslink density (γ) of 5.05×10-3 for HDI-based polymer with corresponding average molecular weight between crosslinks (Mc) of 197.87 gmol-1 The polyurethane elastomers are stable up to 250-265oC with order of stability: HDPU-1.50>MDPU-1.50>TDPU-1.50. The results showed that diol from Ximenia americana seed oil is effective for production of polyurethane elastomers with properties which are comparable to ones of the non-oil-based polymers.