Search Results (155)

The olive oil sector constitutes a fundamental pillar in the Mediterranean region from socio-economic and cultural perspectives. Nonetheless, it produces significant amounts of waste, leading to numerous environmental issues. These waste streams contain valuable compounds that can be recovered and utilized as inputs for various applications. This study introduces a novel value chain for olive wastes, focused on extracting lignin from olive pomace by ionic liquids and polyphenols from olive mill wastewater, which are then incorporated as hybrid nanoparticles in the formulation of an innovative starch-based biofertilizer. This biofertilizer, obtained by using residual wastewater as a source of soluble nitrogen, acting at the same time as a plasticizer for the biopolymer, was demonstrated to surpass traditional NPK biofertilizers’ efficiency, allowing for root growth and foliage in drought conditions. In order to recognize the environmental impact due to its production and align it with the technical output, the circularity and environmental performance of the proposed system were innovatively evaluated through a combination of Life Cycle Assessment (LCA) and the Material Circularity Indicator (MCI). LCA results indicated that the initial upcycling process was potentially characterized by significant hot spots, primarily related to energy consumption (>0.70 kWh/kg of water) during the early processing stages. As a result, the LCA score of this preliminary version of the biofertilizer may be higher than that of conventional commercial products, due to reliance on thermal processes for water removal and the substantial contribution (56%) of lignin/polyphenol precursors to the total LCA score. Replacing energy-intensive thermal treatments with more efficient alternatives represents a critical area for improvement. The MCI value of 0.84 indicates limited potential for further enhancement. Full article

Objectives: This study aims to evaluate the clinical and microbiological efficacy of a novel Activated Ozonated Extra-Virgin Olive Oil (AOEOO) gel as a topical adjunct in the treatment of periodontal pockets. Methods: In this double-blind, randomized clinical trial, patients diagnosed with stage II–IV periodontitis received either scaling and root planing (SRP) and placebo gel or SRP combined with subgingival AOEOO gel application (test group). Periodontal indices—probing pocket depth (PPD), clinical attachment level (CAL), plaque index (PI), and bleeding on probing (BOP)—were measured at baseline, 3, and 6 months. Microbiological analysis using real-time PCR quantified six key periodontal pathogens at baseline and after 6 months. Results: AOEOO-treated patients showed significantly greater improvements in PPD, CAL, PI, and BOP at both 3 and 6 months compared to the placebo group (p < 0.05). Also, microbiologically, the AOEOO group exhibited a significant reduction in total bacterial load and in all target pathogens, with reductions ranging from 63.8% to 98.7% (p < 0.05). No adverse effects were reported. Conclusions: The adjunctive use of AOEOO gel significantly improved periodontal outcomes and reduced pathogenic bacterial load, supporting its potential role as a safe and effective supportive treatment in periodontitis management. 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

This study evaluated the effects of different types and rates of locally produced organic residues on soil organic matter (SOM) and soil health in highly degraded loamy soils of olive orchards in arid southern Tunisia. Three residues were tested: poultry manure, raw date palm waste, and composted date palm waste mixed with manure. A randomised field trial was conducted over three years. Two years after application, soil samples were analysed for physical and chemical properties, basal respiration, nitrogen mineralisation, microbial biomass, enzyme activities (dehydrogenase, phosphomonoesterase, β-glucosidase, urease, arylsulphatase), and community-level physiological profiles. All residues increased SOM and available phosphorus (Pi), with dose-dependent effects sustained over time, though significant increases were only observed at the highest application rates. The most notable improvements occurred in soils amended with composted date palm waste. In contrast, biological and biochemical parameters showed little response, even after remoistening to stimulate microbial activity. This limited response was attributed to the absence of vegetation and, consequently, of root exudates and plant residues. This will be further investigated by assessing changes in the same biological and biochemical properties following the implementation of an intercropping system, which is expected to enhance both SOM content and microbial activity in these soils. Full article

Although the benefits of rational grazing by polygastric animals are well known, little is understood about how chicken grazing affects soil biological health and its capacity to store organic matter. This study aimed to assess the impact of long-term free-range chicken grazing in an olive grove on the soil chemical and biochemical properties, including the total organic carbon (TOC), total nitrogen (TN), microbial biomass (Cmic), basal respiration, and microbial community structure, as well as the soil’s capability to stock organic carbon and total nitrogen. A field experiment was conducted in an olive grove grazed by chickens for over 20 years, with the animal load decreasing with distance from the poultry houses. At 20 m, where the chicken density was highest, the soils showed reduced OC and TN contents and a decline in fungal biomass. This was mainly due to the loss of both aboveground vegetation and root biomass from intensive grazing. At 50 m, where grazing pressure was lower, the soil OC, TN, and microbial community size and activity were similar to those in a control, ungrazed area. These findings suggest that high chicken density can negatively affect soil health, while moderate grazing allows for the recovery of vegetation and soil organic matter. Rational management of free-range chicken grazing, particularly through the control of chicken density or managing grazing time and frequency, is therefore recommended to preserve soil functions and fertility. Full article

The phytochemical investigation and evaluation of the antioxidant activity of the leaves, bark, and roots of Cochlospermum angolense Welw ex Oliv—a valued plant that is widely used in traditional Angolan medicine—hold significant importance. Compounds were extracted from the aforementioned plant using acetone and ethanol and identified by HPLC-ESI-MSn. Both extracts demonstrated notable abilities to scavenge 2,2-diphenyl-1-picrylhydrazyl, nitric oxide, and superoxide radicals, as well as to inhibit lipid peroxidation. A HPLC analysis revealed a diverse array of bioactive compounds, including flavonoids, phenols, alkaloids, quinones, and terpenes, which help neutralize free radicals and protect cells against oxidative stress, thereby contributing to the prevention of various diseases. Moreover, the acetone and ethanol extracts proved to be excellent sources of antioxidants. For the first time, the present study identified new compounds never reported in this species, such as (+)-abscisic acid, angustine B, pinobanksin, dihydrogenistein, (−)-8-prenylnaringenin, isoquercetin, samandarine, dihydromyricetin, and eupatoriocromene, in the leaves, bark, and roots, marking a significant advance in the chemical characterization of C. angolense. These findings enhance our understanding of the bioactive phytochemicals and antioxidant properties of C. angolense and open new avenues for future therapeutic and pharmacological research, further supporting its traditional use in Angolan medicine. 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

This study evaluated the chemical properties of phosphocompost extracts and their effectiveness in inducing tomato seedlings resistance to Meloidogyne javanica. Phosphocomposts: Sugar beet phosphocompost (PC-SB: CP2), green waste phosphocompost (PC-GW: CP3), and olive mill waste phosphocompost (PC-OMW: CP4), were utilized to produce compost water extracts at concentrations of 1:5, 1:10, 1:20, and 1:100 g:mL and then applied as soil drenches for tomato seedlings one-week post-inoculation. The CP2 extract applied at a 1:5 dilution led to marked improvements in growth parameters, with plant height increasing by over 52.2%, shoot fresh biomass rising by approximately 52.44%, and shoot dry biomass showing a gain of 62.21%. Root biomass also rose by 33%. Chlorophyll a increased with CP4 at 1:5 and 1:100 (41.05% and 37.32%), chlorophyll b increased with CP3 at 1:5 and 1:10 (22.34% and 7.59%), while carotenes showed no variation. Polyphenols rose by 86.45–91.01% with CP2 from 1:5 to 1:20, and flavonoids increased by 64.90% with CP4 at 1:10. CP2 diminished the ultimate M. javanica population and reproduction factor by 171.43%, while CP4 at 1:20 decreased egg masses by 151.94%. The root gall index showed no variation. The chemical composition of phosphocomposts revealed that the strategic incorporation of diverse organic improvers (10%) in phosphocomposts yielded distinct nutrient signatures, with sugar beet waste enhancing PO₄³⁻ (12.91 mg/L) and secondary macronutrients, green waste optimizing NO₃⁻ (69.91 mg/L) and SO₄²⁻ (62.70 mg/L) availability, and olive mill waste producing superior micronutrient concentrations alongside dominant Ca (24.21 mg/L), K (392.50 mg/L), and P (9.17 mg/L) levels. Overall, the results underscore the potential of phosphocompost extracts as a viable, low-cost, and eco-friendly alternative to synthetic nematicides, offering a sustainable and resilient approach to M. javanica control while enhancing tomato plant growth. Full article

The development of sustainable seed coating formulations is essential to enhance crop performance while reducing reliance on synthetic inputs. This study evaluates biochar-enriched coatings incorporating olive pomace, buffalo digestate, and microbial consortia from Fagus, Quercus, and Pinus forest litters, including Trichoderma harzianum, for their effects on seed germination and plant growth. Four crops (Diplotaxis tenuifolia, Lactuca sativa, Solanum lycopersicum, and Zea mays) were tested through germination assays and field trials. Treatments containing digestate or pomace alone significantly reduced germination and seedling growth in D. tenuifolia and L. sativa (below 25%, compared to control), due to the phytotoxic effects of ammonia, salts, and polyphenols. In contrast, biochar-based coatings mitigated these effects, enhancing germination and root elongation. The addition of T. harzianum further improved seedling establishment, likely by enhancing nutrient uptake and suppressing soilborne pathogens, with increases exceeding 100% (compared to control). Field trials confirmed these findings, showing that biochar–T. harzianum combinations improved both shoot and root biomass, particularly in L. sativa and S. lycopersicum. Z. mays displayed greater tolerance to raw by-products, though biochar remained essential for optimal growth. While forest-derived microbial consortia supported microbial balance, their effect on biomass was less pronounced. These results highlight the potential of biochar-based coatings, especially when combined with T. harzianum, as sustainable alternatives to conventional seed treatments. Full article

Auxin response factor (ARF) is a plant-specific transcription factor that responds to changes in auxin levels, regulating various biological processes in plants such as flower development, senescence, lateral root formation, stress response, and secondary metabolite accumulation. In this study, we identified the ARF gene family in Populus euphratica Oliv. using bioinformatics analysis, examining their conserved structural domains, gene structure, expression products, and evolutionary relationships. We found that the 34 PeARF genes were unevenly distributed on 19 chromosomes of P. euphratica. All 56 PeARF proteins were hydrophilic and unstable proteins localized in the nucleus, with secondary structures containing α-helices, extended strands, random coils, and β-turns but lacking transmembrane helices (TM-helices) and signal peptides. Evolutionary analysis divided the PeARF proteins into five subfamilies (A–E), with high conservation observed in the order and number of motifs, domains, gene structure, and other characteristics within each subfamily. Expression pattern analysis revealed that 17 PeARF genes were upregulated during cell growth and heterophylly development. This comprehensive analysis provides insights into the molecular mechanisms of ARF genes in P. euphratica growth, development, and stress response, serving as a basis for further studies on the auxin signaling pathway in P. euphratica. Full article

Agricultural intensification often contributes to soil degradation. Mulch and biochar help reduce erosion and runoff while improving organic matter and crop habitat. However, optimal application strategies and the combined advantages of mulch and biochar remain underexplored. This study aimed to evaluate how biochar and mulch affect soil hydrology, erosion, and phytotoxicity, under mixed and layered application strategies: (i) biochar mix (2.8% by weight); (ii) biochar layer (surface application of 10 Mg ha⁻¹); (iii) mulch layer (2 Mg ha⁻¹ of straw mulch); and (iv) mulch + biochar layer (a straw mulch layer of 2 Mg ha⁻¹ on top of a biochar layer of 10 Mg ha⁻¹). Thirty-minute rainfall simulations (at 85.6 mm h⁻¹) on sandy loam soils of a vineyard and olive orchard tested treatment effects on soil hydrology and erosion. The leachate collected from the simulations was used to test treatments phytotoxicity, using Lactuca sativa L. Runoff and interrill erosion decreased by 52–91% and 55–81%, respectively, with the greatest reductions in the treatments that included a mulch layer. Biochar increased root length (29–45%), while mulch had no significant effect. The mulch + biochar treatment performed best, highlighting the products’ complementary benefits in reducing soil degradation and improving soil habitat. Full article

The endophytic strain Amfr20 was isolated from roots of the olive tree var. Amfissa. Based on core-genome phylogenomic analyses, it was classified as Bacillus velezensis. The isolate showed positive results in numerous plant growth promoting traits, as well as in abiotic stress tolerance and in colonization related traits in vitro. Furthermore, the strain exhibited antifungal activity in vitro through diffusible and volatile compounds. Whole genome analysis revealed that the strain possesses large and various arsenals of secondary metabolite biosynthetic gene clusters involved in the bioagent’s functional properties, including plant growth promotion, colonization, and plant defense elicitation, as well as having the genomic potential for abiotic stress mediation. Based on TLC-bioautography, the ethyl acetate extracts of secreted agar-diffusible compounds from Amfr20 through single and dual cultures were found to be bioactive independently of the fungal pathogen’s interaction. The bacterial endophyte also proved efficient in suppressing the severity of anthracnose olive rot and gray mold post-harvest diseases on olive fruits and table grape berries, respectively. Lastly, Amfr20 beneficially affected Arabidopsis thaliana growth under normal and saline conditions, while boosting the plant development of Solanum lycopersicum through seed biopriming and root irrigation methods. The results of this multilevel study indicate that the novel endophyte Amfr20 Bacillus velezensis is a promising bioagent that should be exploited in the future as an ecological biopesticide and/or biostimulant. Full article

Soil salinisation is threatening crop sustainability worldwide, mainly due to anthropogenic climate change. Molecular mechanisms developed to counteract salinity have been intensely studied in model plants. Nevertheless, the economically relevant olive tree (Olea europaea subsp. europaea L.), being highly exposed to soil salinisation, deserves a specific review to extract the recent genomic advances that support the known morphological and biochemical mechanisms that make it a relative salt-tolerant crop. A comprehensive list of 98 olive cultivars classified by salt tolerance is provided, together with the list of available olive tree genomes and genes known to be involved in salt response. Na⁺ and Cl^– exclusion in leaves and retention in roots seem to be the most prominent adaptations, but cell wall thickening and antioxidant changes are also required for a tolerant response. Several post-translational modifications of proteins are emerging as key factors, together with microbiota amendments, making treatments with biostimulants and chemical compounds a promising approach to enable cultivation in already salinised soils. Low and high-throughput transcriptomics and metagenomics results obtained from salt-sensitive and -tolerant cultivars, and the future advantages of engineering specific metacaspases involved in programmed cell death and autophagy pathways to rapidly raise salt-tolerant cultivars or rootstocks are also discussed. The overview of bioinformatic tools focused on olive tree, combined with machine learning approaches for studying plant stress from a multi-omics perspective, indicates that the development of salt-tolerant cultivars or rootstocks adapted to soil salinisation is progressing. This could pave the way for ‘smart oliviculture’, promoting more productive and sustainable practices under salt stress. Full article

Verticillium wilt caused by the soil-borne fungus Verticillium dahliae causes severe losses to a broad range of economically important crops worldwide. Chemical disease management is ineffective; thus, alternative control strategies are needed. Olive-producing countries face the challenge of managing olive mill wastewater (OMW) in an environmentally friendly and agronomically beneficial manner. The proper use of OMW supported by scientific research has been proposed as a valuable means for successful disease management. In this respect, we tested whether soil application of raw OMW can protect vegetable crops against V. dahliae and investigated the potential disease-suppressive mechanisms. OMW inhibited significantly fungal growth, sporulation, hyphae width, and conidial and microsclerotial germination in vitro, and these effects were dose-dependent. Moreover, the addition of OMW in the soil provided sufficient protection of eggplant and tomato against V. dahliae in planta. The high OMW-conferred protection of eggplant was gradually decreased, possibly due to the decreased phenolic content in OMW over time. Bioassays with sterilized soil substrate and OMW, along with isolated microbial strains, revealed that soil- and OMW-originated microbes had no role in disease suppression. Moreover, split-root set-ups suggested a non-systemic OMW-induced resistance mechanism. Root-drench application of OMW in eggplant and tomato plants did not cause significant alterations in the structure of the plant microbiome that could be associated with disease suppressiveness. Full article

The olive tree is one of the most important fruit crops grown in Morocco, yet extensive decline associated with the root rot of this crop has been observed in many regions. This study aimed to identify and characterize the oomycetes associated with root rot disease in olive trees. During the 2021 and 2022 growing seasons, symptomatic root tissues and soil samples were collected for isolation. Based on morphological traits and the sequencing of the internal transcribed spacer (ITS) region of rDNA, 10 oomycete species were identified, belonging to the Phytophthora and Pythium sensu lato (s.l.) genera. Seven species were assigned to Phytophthora, namely, P. palmivora, P. plurivora, P. acerina, P. oleae, P. cactorum, P. gonapodyides, and P. megasperma. The Pythium s.l. genus was represented by three species, including P. schmitthenneri, P. aphanidermatum, and P. irregulare. A pathogenicity assay was conducted by soil infestation to evaluate the effect of these pathogens on one-year-old olive saplings (var. Picholine Marocaine). Results revealed that all 10 species were pathogenic to olive saplings. Inoculated saplings exhibited symptoms, such as root rot, vascular discoloration, and wilting. The pathogens were successfully re-isolated from necrotic roots, thereby fulfilling Koch’s postulates. These findings highlight the complex etiology of root rot disease in olive trees, as multiple species can induce similar symptoms. This study represents the first detailed report of Phytophthora and Pythium s.l. species associated with olive root rot disease in Morocco. Full article