Search Results (81)

The necrotrophic pathogen Sclerotinia sclerotiorum compromises the physiological and anatomical integrity of cotton, leading to substantial economic losses due to rapid tissue necrosis, stem blight, boll rot, and leaf wilting. In this context, the use of endophytic microorganisms emerges as a promising strategy for the biocontrol of white mold. This study tested the hypothesis that endophytic fungal strains isolated from the roots of Butia purpurascens, a palm tree endemic to the Cerrado biome, could mitigate disease symptoms in Gossypium hirsutum L. To evaluate this, cotton plants were subjected to biotic stress imposed by S. sclerotiorum to assess the effectiveness of seven fungal strains in attenuating disease. The impact of the pathogen was monitored through growth variables, gas exchange, leaf temperature, chlorophyll a fluorescence, antioxidant enzyme activity, proline and malondialdehyde (MDA) levels, and the incidence of rot in petioles, leaves, and flower buds. Overall, inoculation with endophytic fungi significantly alleviated the effects of the phytopathogen, promoting vegetative growth and optimizing physiological performance. Treated plants exhibited alleviated stress in primary photochemistry, reduced non-photochemical energy dissipation, and stable carbon fixation. Additionally, efficient modulation of the antioxidant system and preservation of anatomical structures were observed, minimizing the severe symptoms of white mold. Notably, the non-pathogenic strains BP10EF (Gibberella moniliformis), BP16EF (Penicillium purpurogenum), and BP33EF (Hamigera insecticola) acted as potent physiological modulators, yielding responses similar to those of healthy plants. These results highlight the biotechnological potential of these endophytic strains, which can be explored as both growth promoters and resistance inducers in cotton against white mold. Full article

Palm oil is a major agricultural commodity and an important economic driver in Asia. However, the sustainability and productivity of this crop are constantly threatened by a range of pathogenic fungi, especially Ganoderma boninense. Therefore, this study aimed to develop an eco-friendly hexaconazole-loaded nanoemulsion (Hexa-NE) for effective and targeted fungicide delivery while reducing environmental and health impacts. The optimized Hexa-NE formulation was evaluated for particle size, polydispersity index (PDI), zeta potential, pH, viscosity, and morphology using Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM). Fungicide release, stability, and antifungal activity were conducted to assess the overall efficacy and performance of the formulation. The Hexa-NE exhibited particle size of 105.8 nm, a PDI of 0.358, a zeta potential of −53.53 mV. The formulation remained stable over three months of storage. It also demonstrated favourable physicochemical properties including low viscosity (30.24 mPa·s), low surface tension (23.87 mN/m), and suitable pH (6.14) for foliar application. TEM and SEM analyses confirmed spherical droplets and revealed significant hyphal damage to G. boninense. The antifungal test showed a higher inhibition of 97.1% at 0.1 µM of Hexa-NE as compared to hexaconazole solution which only 40% at the same concentration. Release studies exhibited a sustained release of hexaconazole, which may prolonged fungicidal activity. In conclusion, Hexa-NE showed promising laboratory-scale antifungal performance against G. boninense. These findings support its potential for further investigation as a nanoformulated fungicide for future greenhouse and field evaluations. Full article

Land-use change strongly affects soil microbiota, yet the role of agroecological systems in shaping soil fungal communities remains poorly understood in tropical soils. We evaluated the diversity, trophic modes, community composition, and co-occurrence networks of culturable soil fungal taxa across a land-use gradient in the Colombian Andes–Amazon transition zone. Agroecological systems—including improved pasture (IP), cacao and copoazu agroforestry systems (CaAS and CoAS), secondary forest with agroforestry enrichment (SFAE), and a moriche palm swamp ecosystem (MPSE)—were compared with dominant land-uses (degraded pasture, DP and old-growth forest, OF). Fungi were isolated using the soil dilution plate method and identified based on morphological and molecular characteristics, and soil physicochemical properties were measured to evaluate their relationships with fungal community patterns. A total of 420 isolates were assigned to 93 fungal species. Alpha-diversity metrics revealed significantly higher fungal richness in OF and MPSE, and higher Shannon diversity in agroforestry and forest-based systems, whereas DP exhibited the lowest values. Ordination analyses showed clear differences in fungal community composition, with CoAS displaying the most distinct assemblage. Agroecological and forest-based systems favored saprotrophic and symbiotrophic modes. Co-occurrence network analyses indicated that MPSE, OF, and IP supported more complex and modular fungal networks. Soil pH and total phosphorus (TP) were key drivers of fungal community composition, whereas exchangeable calcium, TP, soil organic carbon, and base saturation were associated with network attributes. Overall, our findings highlight the importance of agroecological management for soil fungal diversity and network organization in Amazonian transition landscapes. Full article

Arbuscular mycorrhizal fungi (AMF) play a pivotal role in plant adaptation to arid ecosystems, yet their widespread agricultural use is constrained by the scarcity of high-quality, locally adapted inoculum. This study established a reliable monoxenic culture system for mass-producing an indigenous AMF isolate from the date palm (Phoenix dactylifera L.) rhizosphere in the Figuig oasis, southeastern Morocco. The isolate was identified as Rhizophagus irregularis based on spore morphology and Large Subunit ribosomal DNA (LSU rDNA) phylogeny. Two propagule types, surface-sterilized spores and mycorrhizal root fragments of Plantago lanceolata L., were compared for initiation of in vitro cultures on Ri T-DNA-transformed carrot (Daucus carota L.) hairy roots. By week 16, cultures initiated from mycorrhizal root fragments produced 1414 ± 65 spores per plate and showed significantly higher performance than spore-derived cultures in terms of propagule viability, root colonization, and hairy root growth. Propagule viability reached 84% and 68%, root colonization frequencies were 95% and 72%, and hairy root lengths averaged 81 and 63 cm in root fragment- and spore-derived cultures, respectively (p < 0.01). In a subsequent whole-plant assay using P. lanceolata, in vitro-produced spores induced markedly higher mycorrhizal colonization frequency (91.0 ± 1.6% compared with 74.8 ± 1.9%) and intensity (70.0 ± 1.6% compared with 55.0 ± 1.6%) than spores obtained from conventional trap cultures (p < 0.001). These results demonstrate that monoxenic root-organ culture using root fragments is a robust, reproducible method for generating abundant, contaminant-free, and functionally superior inoculum of native R. irregularis. This advance provides a solid platform for developing tailored bio-inoculants to enhance crop resilience and sustainability in arid and semi-arid agroecosystems. Full article

Vegetable oil is a carbon-rich resource applied in liquid fermentation for compounds of interest. In this study, olive oil demonstrated the best effect on improving the liquid fermentation of a medicinal fungus Poria cocos (Schw.) Wolf compared to rapeseed, coix seed, palm, peanut, and soybean oils. When 2% (v/v) olive oil was initially added to the medium, biomass reached a maximum value of 11.7 g L⁻¹, presenting a 3.1-fold enhancement compared to the blank control. Due to the stronger basal metabolism, the total triterpenoid yields also exhibited a significant improvement of ~3.4-fold, reaching 0.68 g L⁻¹. Spectrophotometry, along with fluorescence and chemiluminescence probe assays, demonstrated that olive oil affected the fungus membrane fluidity and level of reactive oxygen species and nitrogen oxide in mycelium cells. Transcriptome analysis confirmed that olive oil was used as a carbon resource and elicitor that affected mycelia growth, which simultaneously produced some slight effects on metabolic processes, including fatty acid degradation, TCA cycle, and glycolysis/gluconeogenesis. Our study represents an attractive strategy for the industrial fermentation of filamentous fungi. Full article

Yellow leaf disease (YLD) has been the most severe disease threatening areca palm, commonly known in areca palm cultivation. However, it has not yet been systematically studied in terms of the relationship between infected plants and the structure of rhizosphere microbial communities. In order to systematically study the impact of YLD on the rhizosphere fungi of the areca palm, we implemented high-throughput sequencing technology to analyze the microbial community structure and diversity under different disease conditions. The results indicate that as the severity of the disease increases, the diversity of the fungal community diminishes, with species abundance and richness initially decreasing before subsequently increasing, while phylogenetic diversity increases, and significant changes occur in the structure of the soil fungal community. At the phylum level, the dominant fungal phyla in the rhizosphere of areca palm are Ascomycota and Basidiomycota. At the genus level, the dominant genera are Sarocladium, Roussoella, Penicillium, etc., and their relative abundance increases with the severity of the disease. LEfSe analysis revealed that Archaeorhizomyces, Codinaea, and Albifimbria serve as indicator species for healthy areca palms, with their relative abundance trends consistent with changes in Alpha diversity. FUNGuild prediction results indicated that the fungal nutrient type structures of the three rhizosphere samples were highly similar, with saprotrophs being the absolutely dominant type. With the increase in the severity of the disease, the number of harmful fungi in the soil (such as Plectosphaerella, Fusarium, etc.) increases, thereby limiting the sustainable development of the soil. Network analysis indicates that beneficial microbial communities such as Stachybotrys and Roussoella exhibit extensive negative interactions. Therefore, the YLD of areca palm significantly alters the structure and diversity of the rhizosphere fungal community. Simultaneously, some beneficial microorganisms may be recruited by the areca rhizosphere to resist the invasion of YLD by improving the rhizosphere environment and enhancing plant immunity, such as Trechispora, Saitozyma, and Marasmiellus. This experiment is expected to provide a theoretical basis for the study of the rhizosphere microecology of the areca palm, the exploration of excellent biocontrol resources, and the green control of YLD in the areca palm. Full article

This study presents the first molecular characterization of arbuscular mycorrhizal fungi (AMF) isolated from single-spore cultures in Morocco, specifically from the rhizosphere of date palm (Phoenix dactylifera L.) in the Figuig oasis. Nine indigenous AMF isolates were successfully established and identified through an integrative approach combining spore morphology with ribosomal DNA region sequencing (SSU–ITS–LSU). Morphological and phylogenetic analyses revealed that the isolates belonged mainly to the genera Rhizophagus and Glomus. These results provide new insights into AMF diversity in arid Moroccan ecosystems and establish a reference collection of indigenous isolates with potential applications. In particular, they open opportunities for developing bio-inoculants that can improve date palm growth, enhance resilience to environmental stresses, and contribute to sustainable agriculture and soil restoration in oasis systems. Full article

Aims: The aim of this study was to elucidate the effect of Elaeagnus angustifolia Linn. (E. angustifolia L.) on the structure and abundance of the soil microbial community. This paper provides a theoretical foundation for guiding the establishment of E. angustifolia L. forests to enhance the physicochemical properties of soil. Methods: This study employed high-throughput sequencing technology to analyse the composition, diversity, and structural changes of various soil fungal and bacterial communities and correlated the results with soil physicochemical properties. Results: The results indicated a significant increase in the total nitrogen (0.66 g/kg–0.87 g/kg), ammonium nitrogen (3.60 mg/kg–6.56 mg/kg), and organic matter (1.06–1.38%) contents of the inter-rhizosphere soil of E. angustifolia L. after 3, 4, and 5 months of planting. Additionally, the total phosphorus, potassium, and nitrate nitrogen contents increased, whereas soil pH and salinity decreased. The abundance of soil microbial communities also increased. The fungal phyla with relative abundances greater than 1% were Ascomycota, Fungi_unclassified, Basidiomycota, Zygomycota, and Glomeromycota. Chytridiomycota, Rozellomycota, Mortierellomycota, and Olpidiomycota were not found in the bare soil control but were observed in the rhizosphere soil of the date palm. The relative abundance of bacteria from the phyla Proteobacteria, Acidobacteria, Actinobacteria, Gemmatimonadetes, and Chloroflexi in the inter-root soil of jujube dates showed an increase in comparison with the control group. At the same time, correlation analysis found that soil total phosphorus, nitrogen content, and soil enzyme activity were positively correlated with the bacterial level, with TN (p < 0.01) and NO₃⁻-N (p < 0.05) showing significant positive correlations. Conversely, soil pH and salinity were mostly negatively correlated with the fungi, and soil enzyme activity was significantly correlated with the fungal and bacterial at different RAD levels. Conclusions: The introduction of E. angustifolia L. markedly affected the physicochemical properties and microbial community composition of the soil. Full article

An indigenous consortium of arbuscular mycorrhizal fungi (AMF) from the Figuig oasis in southern Morocco, comprising Rhizophagus sp., Funneliformis sp., Acaulospora sp., Sclerocystis sp., and Scutellospora sp., was evaluated for its effects on the growth and sensitivity of Phoenix dactylifera L. variety (cv. Boufeggous Gharas) to Fusarium oxysporum f. sp. Albedinis (Foa), the causal agent of Bayoud disease. Despite its high fruit quality and local appreciation, the Boufeggous Gharas variety is highly susceptible to Foa and is currently at risk of extinction, underscoring the urgent need for its sustainable management. The results demonstrated that Boufeggous Gharas seedlings inoculated with a consortium of indigenous AMF showed significantly improved shoot and root length, leaf number, and biomass as compared to non-mycorrhized seedlings. In contrast, Foa-infected seedlings showed significantly reduced growth, with a 46.6% decrease in shoot height and a 50.4% reduction in root length compared to non-infected seedlings. Interestingly, AMF inoculation mitigated this sensitivity to Foa, significantly restoring growth parameters. Seedlings treated with AMF + Foa showed a 51% increase in shoot height and a 61% improvement in root length, along with over 100% gains in shoot and root biomass compared to seedlings infected solely with Foa. This study provides the first evidence of integrating AMF into sustainable date palm cultivation practices to mitigate the impacts of biotic stresses, thereby promoting the preservation and valorization of vulnerable date palm varieties. The protective effects of AMF are attributed to improved nutrient uptake, enhanced root architecture, and systemic resistance induced by AMF colonization. Full article

Palm trees (Arecaceae) are among the most popular ornamental plants worldwide. Despite extensive research on the fungi associated with Arecaceae, the diversity and ecological dynamics of fungi affecting ornamental palms remain poorly studied, although they have significant impact on palm health and economic value. Furthermore, while research on palm fungal diversity has traditionally focused on tropical assemblages, ornamental palms in temperate climates offer a unique opportunity to explore the diversity of palm fungi in non-native habitats. The present study conducted a preliminary assessment of the diversity and ecology of potential phytopathogenic fungi associated with foliar lesions on various ornamental palm host species in Portugal, combining morphological examination, PCR-based genomic fingerprinting, and biodiversity data analysis. The examination of 134 foliar lesions sampled from 100 palm trees resulted in a collection of 2064 palm leaf spotting fungi (PLSF), representing a diverse fungal assemblage of 320 molecular operational taxonomic units (MOTUs) across 97 genera. The overall fungal community composition revealed a distinct assemblage dominated by Neosetophoma, Alternaria, Phoma, and Cladosporium, with a profusion of infrequent and rare taxa consistent with a logseries distribution. Significantly positive co-occurrence (CO) patterns among prevalent and uncommon taxa suggest potential synergistic interactions enhancing fungal colonisation, persistence, and pathogenicity. The taxonomic structures of the PLSF contrasted markedly from tropical palm fungi, especially in the prevalence of pleosporalean coelomycetes of the Didymellaceae and Phaeosphaeriaceae, including recently introduced or not previously documented genera on Arecaceae. This novel assemblage suggests that climatic constraints shape the structure of palm fungal communities, resulting in distinctive temperate and tropical assemblages. In addition, the fungal assemblages varied significantly across palm host species, with temperate-native palms hosting more diverse, coelomycete-enriched communities. The present findings highlight foliar lesions as hyperdiverse microhabitats harbouring fungal communities with intricate interactions and a complex interplay of climatic, host, and ecological factors. With climate change altering environmental conditions, the identification of fungi thriving in or inhabiting these microhabitats becomes crucial for predicting shifts in pathogen dynamics and mitigating future fungal disease outbreaks. Understanding these complex ecological dynamics is essential for identifying potential phytopathogenic threats and developing effective management strategies for the health and sustainability of ornamental plants. Full article

Arid ecosystems constitute a promising source of actinobacteria producing new bioactive molecules. This study aimed to explore different biological activities of actinomycetes isolated from the rhizosphere of Phoenix dactylifera L. in the Ghardaia region, Algeria. A total of 18 actinobacteria were isolated and studied for their enzymatic and antimicrobial activities. All isolates shared cellulase and catalase activity; most of them produced amylase (94%), esterase (84%), lecithinase and lipoproteins (78%), caseinase (94%), and gelatinase (72%). The isolates could coagulate (56%) or peptonize (28%) skim milk. Overall, 72% of the isolates exhibited significant antibacterial activity against at least one test bacteria, while 56% demonstrated antifungal activity against at least one test fungi. Based on enzyme production and antimicrobial activity, isolate SGI16 was selected for secondary metabolite extraction by ethyl acetate. The crude extract of SGI16 was analyzed using DPPH and BSA denaturation inhibition tests, revealing significant antioxidant power (IC₅₀ = 7.24 ± 0.21 μg mL⁻¹) and protein denaturation inhibitory capacity (IC₅₀ = 492.41 ± 0.47 μg mL⁻¹). Molecular identification based on 16S rDNA analysis showed that SGI16 belonged to the genus Streptomyces. The findings highlight that date palms’ rhizosphere actinobacteria are a valuable source of biomolecules of biotechnological interest. Full article

Innate immunity, the body’s initial defense against bacteria, fungi, and viruses, heavily depends on antimicrobial peptides (AMPs), which are small molecules produced by all living organisms. Insects, with their vast biodiversity, are one of the most abundant and innovative sources of AMPs. In this study, AMPs from the red palm weevil (RPW) Rhynchophorus ferrugineus (Coleoptera: Curculionidae), a known invasive pest of palm species, were examined. The AMPs were identified in the transcriptomes from different body parts of male and female adults, under different experimental conditions, including specimens collected from the field and those reared in the laboratory. The RPW transcriptomes were examined to predict antimicrobial activity, and all sequences putatively encoding AMPs were analyzed using several machine learning algorithms available in the CAMP_R3 database. Additionally, anticancer, antiviral, and antifungal activity of the peptides were predicted using iACP, AVPpred, and Antifp server tools, respectively. Physicochemical parameters were assessed using the Antimicrobial Peptide Database Calculator and Predictor. From these analyses, 198 putatively active peptides were identified, which can be tested in future studies to validate the in silico predictions. Genome-wide analysis revealed that several AMPs have predominantly emerged through gene duplication. Noticeably, we detect a newly originated defensin allele from an ancestral defensin via the deletion of two amino acids following gene duplication in RPW, which may confer an enhanced resilience to microbial infection. Our study shed light on AMP gene families and shows that high duplication and deletion rates are essential to achieve a diversity of antimicrobial mechanisms; hence, we propose the RPW AMPs as a model for exploring gene duplication and functional variations against microbial infection. Full article

The Dubas bug is a serious and widespread pest of date palms in several countries in the Middle East. Chemical pesticides are widely used for managing this pest; however, most pesticides fail due to the continuous development of pesticide resistance. The primary goal of this research was to isolate endophytic fungi and test their entomopathogenic activity against Dubas bug nymphs and adults. A total of 27 fungal isolates were obtained and identified using the nuc rDNA internal transcribed spacer (ITS1-5.8S-ITS2 = ITS) region. These strains represent 16 species, belonging to 10 genera of seven different families, Ascomycota with six families and Basidiomycota with a single family, Quambalariaceae. Due to its remarkable biological control ability against insect pests, Clonostachys rosea was further studied for its entomopathogenic activity against Ommatissus lybicus nymphs and adults in comparison to a commercial strain of Beauveria bassiana. The concentration of 1 × 10⁸ conidia/mL of the selected endophytic isolate was used in lab experiments targeting Dubas bug healthy nymphs and adults. After 7 days of C. rosea treatment, the isolate caused significant mortality rates of 85% in the adult insects, while the mortality rates were moderate in the nymphs (33%). The commercial strain of B. bassiana resulted in 100% mortality levels in nymphs and adults of the Dubas bug. Scanning electron microscopy (SEM) of O. lybicus adults treated with C. rosea and B. bassiana showed mycelium growing on the eye, antenna, cuticle, and egg oviposition parts of O. lybicus. Mycelium growth of both fungi was also evident on the nymphs. This study reports for the first time the isolation of C. rosea from the Dubas bug, and its high entomopathogenic activity against an adult population of O. lybicus. Full article

Euterpe oleracea Mart., also known for its fruit açaí, is a palm native to the Amazon region. The state of Pará, Brazil, accounts for over 90% of açaí production. Demand for the fruit in national and international markets is increasing; however, climate change and diseases such as anthracnose, caused by the fungus Colletotrichum sp., lead to decreased production. To meet demand, measures such as expanding cultivation in upland areas are often adopted, requiring substantial economic investments, particularly in irrigation. Therefore, the aim of this study was to evaluate the potential of açaí rhizobacteria in promoting plant growth (PGPR). Rhizospheric soil samples from floodplain and upland açaí plantations were collected during rainy and dry seasons. Bacterial strains were isolated using the serial dilution method, and subsequent assays evaluated their ability to promote plant growth. Soil analyses indicated that the sampling period influenced the physicochemical properties of both areas, with increases observed during winter for most soil components like organic matter and C/N ratio. A total of 177 bacterial strains were isolated from rhizospheres of açaí trees cultivated in floodplain and upland areas across dry and rainy seasons. Among these strains, 24% produced IAA, 18% synthesized ACC deaminase, 11% mineralized organic phosphate, and 9% solubilized inorganic phosphate, among other characteristics. Interestingly, 88% inhibited the growth of phytopathogenic fungi of the genera Curvularia and Colletotrichum. Analysis under simulated water stress using Polyethylene Glycol 6000 revealed that 23% of the strains exhibited tolerance. Two strains were identified as Bacillus proteolyticus (PP218346) and Priestia aryabhattai (PP218347). Inoculation with these strains increased the speed and percentage of açaí seed germination. When inoculated in consortium, 85% of seeds germinated under severe stress, compared to only 10% in the control treatment. Therefore, these bacteria show potential for use as biofertilizers, enhancing the initial development of açaí plants and contributing to sustainable agricultural practices. Full article

The fungus Fusarium oxysporum (f.sp. albedinis) causes Bayoud disease. It is one of the epiphytotic diseases that affects a wide range of palm species and has no known cure at present. However, preventive measures can be taken to reduce the effects of the disease. Bayoud disease has caused enormous economic losses due to decreased crop yield and quality. Therefore, it is essential to develop a mathematical model for the dynamics of the disease to propose some affordable methods for disease management. In this study, we propose a novel mathematical model that describes the transmission dynamics of the disease in date palm trees. The model incorporates various factors such as the contact rate of the fungi with date palm trees, the utilization of fungicides, and the introduction of a quarantine compartment to prevent disease dissemination. We first prove a few key properties of the proposed model to ensure that the model is well-posed and suitable for numerical investigations. We establish that the model has a unique positive solution that is bounded and stable over time. We use sensitivity analysis to identify the parameters that have the greatest effect on the reproduction number ${\mathcal{R}}_0$ and illustrate this effect graphically. We then formulate an optimal control problem to identify the most suitable and cost-effective disease control approaches. As a first approach, we solely focus on the application of fungicide to susceptible trees and determine the best spray rates for a greater decrease in exposed and infected trees. Secondly, we emphasize quarantining exposed and infected trees at optimal quarantine rates. Finally, we explore the combined effect of fungicide spraying and isolating infected trees on disease control. The findings of the last approach turn out to be the most rewarding and cost-effective for minimizing infections in date palm trees. Full article