Search Results (412)

In recent years, early olive fruit drop has been observed in the northern Mediterranean regions, causing significant economic losses, although the exact cause remains unknown. Recent studies have identified several possible causes; however, our understanding of how olive trees respond to these environmental stresses remains limited. This study includes an analysis of selected meteorological and flowering data for Olea europaea L. “Istrska belica” to evaluate the use of a chilling and forcing model for a better understanding of flowering time dynamics under a changing climate. The flowering process is influenced by high diurnal temperature ranges (DTRs) during the pre-flowering period, resulting in earlier flowering. Despite annual fluctuations due to various climatic factors, an increase in DTRs has been observed in recent decades, although the mechanisms by which olive trees respond to high DTRs remain unclear. The chilling requirements are still well met in the region (1500 ± 250 chilling units), although their total has declined over the years. According to the Chilling Hours Model, chilling units—referred to as chilling hours—represent the number of hours with temperatures between 0 and 7.2 °C, accumulated throughout the winter season. Growing degree hours (GDHs) are strongly correlated with the onset of flowering. These results suggest that global warming is already affecting the synchrony between olive tree phenology and environmental conditions in the northern Mediterranean and may be one of the reason for the green drop. Full article

Verticillium wilt, caused by Verticillium dahliae, poses a significant threat to olive trees (Olea europaea L.). The isolation of endophytic Streptomyces strains from olive roots has led to the discovery of several strains showing strong antifungal activity against V. dahliae, as demonstrated through in vitro and small-scale soil experiments. Molecular analyses confirmed that strain OE54 belongs to Streptomyces iranensis. The main antifungal compound identified in this strain was rapamycin. Rapamycin displayed potent antifungal effects, notably inhibiting conidiospore germination (IC₅₀ = 87.36 μg/mL) and the hyphal growth of V. dahliae, with a minimum inhibitory concentration (MIC₅₀) of 3.91 ng/mL. Additionally, a second rapamycin-producing strain, OE57^T, was isolated. Phenotypic and genotypic analyses indicated that OE57^T represents a new species, which is proposed to be named Streptomyces lacaronensis sp. nov., with OE57^T designated as the type strain (=DSM 118741^T; CECT 31164^T). The discovery of two endophytic rapamycin-producing Streptomyces strains residing within olive roots is especially notable, given the rarity of rapamycin production among microorganisms. These findings highlight the potential of rapamycin-producing Streptomyces strains in developing biofertilizers to manage V. dahliae and reduce the impact of Verticillium wilt on olive trees and other crops. Full article

Ailanthus altissima (AA) is an invasive tree species rapidly spreading worldwide, colonizing both urban and agricultural or forestry environments. This three-year study aimed to assess its effects on the growth and yield traits of the Koroneiki olive cultivar under co-cultivation in pots, combined with two irrigation regimes, full and deficit irrigation (60% of full). Within each irrigation regime, olive trees were grown either in the presence or absence (control) of AA. The trial evaluated several parameters, including vegetative growth, yield traits, and oil quality characteristics. Co-cultivation with AA had no significant impact on tree growth after three years, though it significantly reduced oil content per fruit. Antioxidant capacity of the oil improved under deficit irrigation, while AA presence did not significantly affect it, except for an increase in o-diphenol concentration. Neither the fatty acid profile nor squalene levels were significantly influenced by either treatment. Fruit weight and color were primarily affected by deficit irrigation. During storage, olive oil quality declined significantly, with pre-harvest treatments (presence or absence of AA and full or deficit irrigation regime) playing a critical role in modulating several quality parameters. In conclusion, the presence of AA near olive trees did not substantially affect the key quality indices of the olive oil, which remained within the criteria for classification as extra virgin. Full article

The intensification of olive growing has raised environmental concerns, particularly regarding nutrient loss from excessive fertiliser use. In line with the European Union’s Farm to Fork strategy, which aims to halve the soil nutrient losses by 2030, this study evaluates the effectiveness of two sensor-based approaches—proximal sensing with a FLAME spectrometer and remote sensing via UAV-mounted multispectral imaging—compared with foliar chemical analyses as the reference standard, for diagnosing the nutritional status of olive trees. The research was conducted in Elvas, Portugal, between 2022 and 2023, across three olive cultivars (‘Azeiteira’, ‘Arbequina’, and ‘Koroneiki’) subjected to different fertilisation regimes. Machine learning (ML) models showed strong correlations between sensor data and nutrient levels: the multispectral sensor performed best for phosphorus (P) (determination coefficient [$R^2$] = 0.75) and potassium (K) ($R^2$ = 0.73), while the FLAME spectrometer was more accurate for nitrogen (N) ($R^2$ = 0.64). These findings underscore the potential of sensor-based technologies for non-destructive, real-time nutrient monitoring, with each sensor offering specific strengths depending on the target nutrient. This work contributes to more sustainable and data-driven fertilisation strategies in precision agriculture. Full article

Computer Vision (CV) has proven to be a powerful tool for automation in agri-food industrial processes, offering high-precision solutions tailored to specific working conditions. Recent advancements in Artificial Neural Networks (ANNs) have revolutionized CV applications, enabling systems to autonomously learn and optimize tasks. However, ANN-based approaches often require complex development and lengthy training periods, making their implementation a challenge. In this study, we explore the use of the Segment Anything Model (SAM), a pre-trained neural network developed by META AI in 2023, as an alternative for industrial segmentation tasks in the table olive (Olea europaea L.) processing industry. SAM’s ability to segment objects regardless of scene composition makes it a promising tool to improve the efficiency of olive pitting machines (DRRs). These machines, widely employed in industrial processing, frequently experience mechanical inefficiencies, including the “boat error,” which arises when olives are improperly oriented, leading to defective pitting and pit splinter contamination. Our approach integrates SAM into n CV workflow to diagnose and quantify boat errors without designing or training an additional task-specific ANN. By analyzing the segmented images, we can determine both the percentage of boat errors and the size distribution of olives during transport. The results validate SAM as a feasible option for industrial segmentation, offering a simpler and more accessible solution compared to traditional ANN-based methods. Moreover, our statistical analysis reveals that improper calibration—manifested as size deviations from the nominal value—does not significantly increase boat error rates. This finding supports the adoption of complementary CV technologies to enhance olive pitting efficiency. Future work could investigate real-time integration and the combination of CV with electromechanical correction systems to fully automate and optimize the pitting process. Full article

The growing threat of antibiotic-resistant Gram-negative bacteria highlights the urgent need for innovative, non-bactericidal therapeutic strategies. Quorum-sensing (QS) inhibition has emerged as a promising approach to attenuate bacterial virulence without exerting selective pressure. This study evaluated the antimicrobial, anti-QS, and antibiofilm properties of aqueous extracts from five medicinal plants native to northeastern Mexico: Gymnosperma glutinosum, Ibervillea sonorae, Larrea tridentata, Olea europaea, and Tecoma stans. Disk diffusion and violacein quantification assays using Chromobacterium violaceum demonstrated significant QS inhibition by G. glutinosum and T. stans, with violacein reductions of 60.02% and 52.72%, respectively, at 40 mg/mL. While L. tridentata and O. europaea exhibited antibacterial activity, I. sonorae showed no growth or pigment inhibition but achieved the highest biofilm disruption (89.89%) against Salmonella typhimurium. UPLC-MS analysis identified chlorogenic acid, kaempferol, and D-(−)-quinic acid as major constituents, compounds previously associated with QS modulation. These findings highlight the potential of traditional Mexican plant species as sources of QS inhibitors and bio-film-disrupting agents, supporting their further development as alternatives to conventional antibiotics. Full article

Olive trees are generally considered a species well-adapted to drought, but the impact of water shortage is of critical importance on olive production. For this reason, developing tolerant cultivars could be an effective strategy to mitigate the impact of drought in the future. Characterizing drought stress tolerance in olive is a complex task due to the numerous traits involved in this response. In this study, plant growth, pressure–volume curves, gas-exchange and chlorophyll fluorescence traits, and stomata characteristics were monitored in nine cultivars to assess the effects of mild and severe drought stress conditions induced by withholding water for 7 and 21 days, respectively, and were compared to a well-watered control treatment. The plant materials evaluated included traditional cultivars, as well as new developed cultivars suited for high-density hedgerow olive orchards or resistant to verticillium wilt. Significant differences between cultivars were observed for most evaluated traits, with more pronounced differences under severe drought conditions. A multivariate analysis of the complete dataset recorded throughout the evaluation period allowed for the identification of promising cultivars under stress conditions (‘Sikitita’, ‘Sikitita-2’, and ‘Martina’) as well as highly discriminative traits that could serve as key selection parameters in future breeding programs. Full article

This study aims to identify the optimal conditions—host, plant material, seasonality, and agricultural practices—for isolating and developing a collection of culturable endophytic microorganisms to support sustainable Olea europaea L. cultivation. Samples were collected from three Sicilian olive cultivars (‘Nocellara del Belice’, ‘Nocellara Etnea’, and ‘Nocellara Messinese’) and six wild olive accessions across different phenological phases and under organic and conventional agronomic management. Endophytes were isolated from leaves and twigs using a culture-dependent approach, and their taxonomic diversity and plant-growth-promoting (PGP) traits were analyzed. A total of 133 endophytic isolates were identified, spanning bacterial (Proteobacteria, Firmicutes, and Actinobacteria) and fungal (Ascomycota and Basidiomycota) phyla. Wild olive trees contributed more than cultivated varieties to enriching the diversity and composition of culturable endophyte collection as well as twigs instead of leaves. Winter sampling allowed to implement the taxonomic genera of olive endophyte collection. Both farming systems favored an increase in the composition of microbial collection, though organic farming systems supported greater microbial richness. Functional analysis highlighted key PGP traits in a selection of bacterial isolates, including indole-3-acetic acid and siderophore production, nitrogen fixation, and antifungal activity. Bacillus spp. dominated enzymatic activities, such as amylase, protease, and lipase production, as well as antifungal activity against the olive fungal pathogen Neofusicoccum vitifusiforme. This research highlights the significant diversity and functional potential of Mediterranean olive endophytes. Our findings emphasize the role of native microbial communities as bio-inoculants, promoting plant growth, nutrient uptake, and disease resistance. These insights lay the groundwork for developing targeted olive-microbial consortia for biocontrol and stress tolerance applications. Full article

Background: Since breast cancer is a major cause of mortality, investigation of the synergistic effect of Olea europaea L. leaf extract in combination with some cancer medications is important for obtaining cost-effective and high-achieving treatments for breast cancer. This study aims to investigate the potential effects of Olea europaea L. extract in inhibiting breast cancer cell growth and enhancing the efficacy of chemotherapy agents against breast cancer under in vitro conditions. Methods: We conducted an analysis of some minerals and vitamins of three different viscosities (200 V, 300 V, and 400 V as a natural food product) of Olea europaea L. leaf water-based extract (OWE) derived from a natural cold maceration. We investigated the cytotoxic effects of Olea europaea L. extract with different viscosities (200–400 V) and various chemotherapy agents, either alone or in combination, in estrogen receptor-positive MCF-7 human breast carcinoma cells by MTT assay. Olea europaea L. extract treatment of cells resulted in growth inhibition in a dose- and time-dependent manner. Results: The 400 V OWE showed the highest calcium (301 ± 12 mg/100 g), potassium (1744 ± 33 mg/100 g), and vitamin E (0.36 ± 0.01 mg/100 g) amounts. Based on MTT results, combinations of 400V Olea europaea L. extract, which exhibited the strongest inhibitory effect with an IC₅₀ value of 940 µg/mL, and anticancer drugs were next assessed for their synergistic efficacy towards cell growth inhibition. Conclusions: Combinations of the IC₅₀ value of 400 V OWE with docetaxel, paclitaxel, and trastuzumab (1 µg/mL) treatment showed a strong synergistic effect in the growth inhibition of MCF-7 cells. Full article

Agricultural practices significantly influence agroecosystem biodiversity, driving a growing focus on the development of environmentally sustainable management strategies. Olive (Olea europaea L.) is one of the most widely cultivated tree crops in the Mediterranean basin and other regions with a Mediterranean climate. In this study, we employed a split-plot design with whole plots arranged as a randomized complete block design (RCBD) to evaluate the effects of minimum tillage and the application of wood distillate to olive canopies on wild vascular plant and soil-dwelling springtail communities in a conventionally managed olive grove in central Italy. Biotic communities were sampled twice, in November and April. Tillage caused a marginally significant decrease in springtail species richness in April and significantly influenced the composition of both plant and springtail communities in April. All the plant species showed a decrease in abundance under tillage, whereas the abundance of springtail species responded to tillage in a species-specific way. Wood distillate had no effect on any community attribute in either season. Springtail total abundance was not affected by any treatment in either season. Our findings confirm that tillage practices affect the diversity of plant and springtail communities. Moreover, we had evidence that spring tillage may have more negative impacts on the studied communities with respect to autumn tillage. Moreover, we suggest that the application of low-concentration wood distillate to olive canopies can be considered, in the short-term, a sustainable agricultural practice that does not negatively affect agroecosystem biodiversity. Full article

The genetic diversity of the olive tree (Olea europaea L.) is critical for enhancing crop resilience and productivity under changing climatic conditions. Peru’s southern region, particularly Tacna, hosts over 30 olive cultivars, yet their genetic structure remains poorly characterized. This study aimed to evaluate the morphological and genomic diversity of ten economically important olive varieties cultivated in 15 sectors across Tacna and Jorge Basadre provinces. A total of 92 mother plants were selected for morphological assessment using 25 standardized descriptors. Additionally, genomic DNA was extracted from 30 samples and subjected to genotyping-by-sequencing (GBS). Quality metrics confirmed the efficiency of a modified 6h-DNA extraction protocol. Bioinformatic analysis identified hundreds of thousands of SNPs per variety, with a high transition/transversion ratio (∼2.1), indicating reliable variant calls. Phylogenetic clustering revealed three diversity groups, with the olive cultivars Ascolana and Frantoio exhibiting high genetic variability, and Arbequina and Leccino—also olive cultivars—showing reduced diversity. The integration of phenotypic and genomic data highlights hidden variability and supports informed selection and conservation strategies. These findings provide a genomic baseline for breeding programs and genetic resource management in emerging olive-growing regions such as southern Peru. Full article

Proximal plant-based monitoring provides high-resolution data about trees, leading to more precise orchard management and in-depth knowledge about tree physiology. The present work focuses on continuous real-time monitoring of olive cv. ‘Ascolana tenera’ over hourly intervals during the third stage of fruit growth (mesocarp cell expansion) under mild water stress conditions (ψStem above −2 MPa). This is achieved by mounting dendrometers on the root, trunk, branch, and fruit to assess and model the behavior of each organ. The diameter variation in each organ over different time intervals (daily, two-weeks, and throughout the entire experiment), as well as their hysteretic patterns relative to each other and vapor pressure deficit, are demonstrated. The results show different correlations between various organs, ranging from very weak to strongly positive. However, the trend of fruit versus root consistently shows a strong positive relationship throughout the entire experiment (R² = 0.83) and a good one across various two-week intervals (R² ranging from 0.54 to 0.93). Additionally, different time lags in dehydration and rehydration between organs were observed, suggesting that the branch is the most reactive organ, regulating dehydration and rehydration in the tree. Regarding the hysteretic pattern, different rotational patterns and characteristics (shape) were observed among the organs and in relation to vapor pressure deficit. This research provides valuable insight into flow dynamics within a tree, models plant water relations and time lags in terms of water storage and transport, and could be implemented for precise olive tree water status detection. Full article

The food industry generates large quantities of biowaste, including olive (Olea europaea L.) leaves, which are rich in phenolic compounds with proven antioxidant and antimicrobial activity. In this study, a microwave-assisted olive leaf extract was produced and evaluated. Antioxidant potential (20.23 ± 0.31 µmol TE g⁻¹), antimicrobial activity against Staphylococcus aureus (MIC 17.62 mg GAE g⁻¹), and cytotoxic effects in breast (MDA-MB-231 (IC₅₀ = 38.9 ± 1.8 µg mL⁻¹), MCF-7 (IC₅₀ = 58.9 ± 5.4 µg mL⁻¹) and prostate cancer PC-3 (IC₅₀ = 69.2 ± 7.6 µg mL⁻¹) cell models were confirmed. Further, the extract was incorporated into a whey protein isolate (WPI) edible coating mixture and applied to semi-hard cheese over a 60-day ripening period. When applied to cheese, WPI-based coatings enriched with OLE contributed to an improved antioxidant potential (289.79 ± 16.16 µmol TE L⁻¹), elevated retention of total phenols and flavonoids, and slightly reduced microbial growth without compromising cheese safety. Compared to the uncoated control, coated samples showed higher total solids (up to 62.87 ± 0.13%, CWPIM) and fat contents (up to 26.59 ± 0.17%, CWPIM), moderated proteolysis (WSN in CWPIM: 3.15 ± 0.09% vs. 4.48 ± 0.02% in C0), maintained cohesiveness and resilience compared to the control, and exhibited less pronounced color deviation (ΔE) in some coated samples during ripening. These results highlight the potential of olive leaf extract as a bioactive, sustainable ingredient for functional edible coatings that improve the nutritional, technological, and microbiological quality of ripened cheese. Full article

Secondary metabolites in olive (Olea europaea L.) leaves constitute a complex framework wherein phenylpropanoids, terpenoids, and secoiridoids in particular, serve as major contributors to olive plant resilience. Silicon (Si) stands as a mediator of defense mechanisms in plants, enhancing their protective responses and adaptability. A field trial on one-year-old plantlets of two metabolically distinct olive genotypes was conducted to investigate the effects of foliar-applied Si on the phytochemical profiles of locally treated leaves. Silicon’s systemic effects in juvenile leaves were also appraised. We accounted for intervarietal differences in nutrient uptake and conducted in situ measurements of physiological indices. The peak of the summer season and the onset of autumn were chosen as the two sampling time points. Intense summer conditions prompted metabolic adjustments that resulted in phytochemical profiles unique to each cultivar. These profiles were further significantly altered by Si while remaining genotype-specific, with substantial increases in prominent compounds like oleuropein (105% and 252%) and verbascoside (62% and 126%), depending on the genotype. As the pressure from environmental factors eased, the differences in Si-mediated phytochemical responses emerged. Silicon had a limited effect on the phytochemical profile of the resilient cultivar which acquired a metabolic steady-state, while it significantly altered the profile of its metabolically more versatile counterpart, resulting with a progressive increase in its oleuropein (37%) and verbascoside (26%) levels. These effects extended to untreated, juvenile leaves as well. While effective in altering and improving the phytochemical composition of olive leaves, Si acted in a manner that adhered to each genotype’s metabolic foundation. The intensity of environmental constraints, along with each cultivar’s inherent sensitivity to them, seems to be tied to silicon’s capacity to mediate significant phytochemical alterations. The extent of silicon’s prophylactic function may therefore be dependent on a genotype’s metabolic foundation and overall sensitivity, and as such it seems inseparable from stress and its intensity. Full article

Understanding the transcriptional responses of plants under cold stress conditions is critical for olive cultivation, particularly in regions prone to extreme weather fluctuations and especially with increasing threats from climate change. In controlled experiments, we subjected leaves of three cold-tolerant and three cold-susceptible cultivars to moderate (−7 °C) and severe (−12 °C) freezing stress, followed by recovery at baseline temperatures. The study measured photosynthetic efficiency and enzymatic activity and showed physiological and gene expression changes using different methods. Distinct transcriptomic adaptations were revealed. Cultivars displayed enhanced differential expression associated with photosynthetic recovery and gene regulation in metabolic pathways. Two overlapping DEGs with increased expression were found in all cultivars during initial freezing. Full article