Search Results (27)

This study investigates the main insects and endophytic fungi that promote the formation of agarwood in Aquilaria sinensis (Lour.) Spreng. and elucidates the effects and mechanisms of different ‘insect + fungus’ combinations on agarwood formation. The results showed that 16 strains of endophytic fungi were isolated from A. sinensis. Fusarium solani, Penicillium chrysogenum, Fusarium equiseti, and Phaeoacremonium alvesii were identified as dominant fungi promoting agarwood formation, while Nadezhdiella cantori was recognized as the dominant insect facilitating this process. The optimal ‘insect + fungus’ combination was Nadezhdiella cantori + Fusarium equiseti. The average agarotetrol contents were 0.046% and 0.054% in February and June, respectively, which were significantly higher than those in cold drilling, fungal-only, and insect-only treatments. RNA sequencing revealed 23,801 differentially expressed unigenes in cjYB1Z4 (optimal combination) versus control BMZ. Upregulated unigenes were enriched in isoflavone biosynthesis, flavonoid biosynthesis, and sesquiterpenoid and triterpene biosynthesis. Fifty sesquiterpene-related differential unigenes encoded seven key enzymes in the MVA pathway, seven key enzymes in the MEP pathway, and seven terpene synthases. Co-expression network analysis indicated that transcription factors (e.g., WRKY33, ABF, WRKY2) potentially regulate agarwood sesquiterpene formation. This work elucidates preliminary effects and molecular mechanisms of insect- and fungi-induced agarwood formation in A. sinensis, advancing agarwood induction technology. Full article

The antifungal effectiveness of essential oils (EOs) and their predominant components were tested on 14 phytopathogenic fungi isolated from olive trees. Commercial EOs from holy basil (Ocimum tenuiflorum L.), Chinese cinnamon (Cinnamomum aromaticum Ness), lemon (Citrus × limon), peppermint (Mentha × piperita L.), oregano (Origanum compactum Benth), and thyme (Thymus vulgaris L.) and components eugenol, e-cinnamaldehyde, limonene, menthol, carvacrol, and thymol were used. Antifungal efficacy was tested on six species from the Botryosphaeriaceae family: Botryosphaeria dothidea (Moug. ex Fr.) Ces. & De Not.; Diplodia mutila (Fr.) Fr.; D. seriata De Not.; Dothiorella iberica A.J.L. Phillips, J. Luque & A. Alves; Do. sarmentorum (Fr.) A.J.L. Phillips, Alves & Luque; and Neofusicoccum parvum (Pennycook & Samuels) Crous, Slippers & A.J.L. Phillips. Other tested species included Biscogniauxia mediterranea (De Not.) Kuntze, B. nummularia (Bull.) Kuntze; Cytospora pruinosa Défago; Nigrospora gorlenkoana Novobr.; N. osmanthi Mei Wang & L. Cai; N. philosophiae-doctoris M. Raza, Qian Chen & L. Cai; Phaeoacremonium iranianum L. Mostert, Grafenhan, W. Gams & Crous; and Sordaria fimicola (Roberge ex Desm.) Ces. & De Not. The results show that Chinese cinnamon and oregano EOs, along with their components, completely inhibited the growth of all tested fungi, indicating their potential as biological control agents in sustainable agriculture. In contrast, the least effective treatments were the EOs derived from lemon and peppermint, as well as the components limonene, menthol, and thymol. Notably, the fungi Do. iberica and N. gorlenkoana were among the most sensitive to all the treatments applied. Full article

Negative plant–soil feedback (PSF) arises when localized accumulations of pathogens reduce the growth of conspecifics, whereas positive PSF can occur due to the emergence of mutualists. Biochar, a carbon-rich material produced by the pyrolysis of organic matter, has been shown to modulate soil microbial communities by altering their abundance, diversity, and activity. For this reason, to assess the long-term impact of biochar on soil microbiome dynamics and subsequent plant performance, we conducted a PSF greenhouse experiment using field soil conditioned over 10 years with Vitis vinifera (L.), without (e.g., C) or with biochar at two rates (e.g., B and BB). Subsequently, the conditioned soil was employed in a response phase involving either the same plant species or different species, i.e., Medicago sativa (L.), Lolium perenne (L.), and Solanum lycopersicum (L.). We utilized next-generation sequencing to assess the abundance and diversity of fungal pathogens and arbuscular mycorrhizal fungi (AMF) within each conditioned soil. Our findings demonstrate that biochar application exerted a stimulatory effect on the growth of both conspecifics and heterospecifics. In addition, our results show that untreated soils had a higher abundance of grape-specialized fungal pathogens, mainly Ilyonectria liriodendra, with a relative abundance of 20.6% compared to 2.1% and 5.1% in B and BB, respectively. Cryptovalsa ampelina also demonstrated higher prevalence in untreated soils, accounting for 4.3% compared to 0.4% in B and 0.1% in BB. Additionally, Phaeoacremonium iranianum was exclusively present in untreated soils, comprising 12.2% of the pathogens’ population. Conversely, the application of biochar reduced generalist fungal pathogens. For instance, Plenodomus biglobosus decreased from 10.5% in C to 7.1% in B and 2.3% in BB, while Ilyonectria mors-panacis declined from 5.8% in C to 0.5% in B and 0.2% in BB. Furthermore, biochar application was found to enrich the AMF community. Notably, certain species like Funneliformis geosporum exhibited increased relative abundance in biochar-treated soils, reaching 46.8% in B and 70.3% in BB, compared to 40.5% in untreated soils. Concurrently, other AMF species, namely Rhizophagus irregularis, Rhizophagus diaphanus, and Claroideoglomus drummondii, were exclusively observed in soils where biochar was applied. We propose that the alleviation of negative PSF can be attributed to the positive influence of AMF in the absence of strong inhibition by pathogens. In conclusion, our study underscores the potential of biochar application as a strategic agricultural practice for promoting sustainable soil management over the long term. Full article

Peach (Prunus persica L.) is one of the most important and oldest stone fruits grown in China. Even though P. persica is one of the most commonly grown stone fruits in China, little is known about the biodiversity of microfungi associated with peach branch diseases. In the present study, samples were collected from a wide range of peach growing areas in China, and fungal pathogens associated with peach branch diseases were isolated. In total, 85 isolates were obtained and further classified into nine genera and 10 species. Most of the isolates belonged to Botryosphaeriaceae (46), including Botryosphaeria, Diplodia, Neofusicoccum, Phaeobotryon, and Lasiodiplodia species; Ascochyta, Didymella, and Nothophoma species representing Didymellaceae were also identified. Herein, we introduce Ascochyta prunus and Lasiodiplodia pruni as novel species. In addition, we report the first records of Nothophoma pruni, Neofusicoccum occulatum, and Phaeobotryon rhois on peach worldwide, and Didymella glomerata, Nothophoma quercina, and Phaeoacremonium scolyti are the first records from China. This research is the first comprehensive investigation to explore the microfungi associated with peach branch disease in China. Future studies are necessary to understand the pathogenicity and disease epidemiology of these identified species. Full article

A three-year survey was conducted to estimate the incidence of grapevine trunk diseases (GTDs) in Greece and identify fungi associated with the disease complex. In total, 310 vineyards in different geographical regions in northern, central, and southern Greece were surveyed, and 533 fungal strains were isolated from diseased vines. Morphological, physiological and molecular (5.8S rRNA gene-ITS sequencing) analyses revealed that isolates belonged to 35 distinct fungal genera, including well-known (e.g., Botryosphaeria sp., Diaporthe spp., Eutypa sp., Diplodia sp., Fomitiporia sp., Phaeoacremonium spp., Phaeomoniella sp.) and lesser-known (e.g., Neosetophoma sp., Seimatosporium sp., Didymosphaeria sp., Kalmusia sp.) grapevine wood inhabitants. The GTDs-inducing population structure differed significantly among the discrete geographical zones. Phaeomoniella chlamydospora (26.62%, n = 70), Diaporthe spp. (18.25%, n = 48) and F. mediterranea (10.27%, n = 27) were the most prevalent in Heraklion, whereas D. seriata, Alternaria spp., P. chlamydospora and Fusarium spp. were predominant in Nemea (central Greece). In Amyntaio and Kavala (northern Greece), D. seriata was the most frequently isolated species (>50% frequency). Multi-genes (rDNA-ITS, LSU, tef1-α, tub2, act) sequencing of selected isolates, followed by pathogenicity tests, revealed that Neosetophoma italica, Seimatosporium vitis, Didymosphaeria variabile and Kalmusia variispora caused wood infection, with the former being the most virulent. To the best of our knowledge, this is the first report of N. italica associated with GTDs worldwide. This is also the first record of K. variispora, S. vitis and D. variabile associated with wood infection of grapevine in Greece. The potential associations of disease indices with vine age, cultivar, GTD-associated population structure and the prevailing meteorological conditions in different viticultural zones in Greece are presented and discussed. Full article

The strains Trichoderma harzianum TH07.1-NC (TH), Aphanocladium album MX95 (AA), Pleurotus eryngii AL142PE (PE) and Pleurotus ostreatus ALPO (PO) were tested as biological limiters against Fomitiporia mediterranea Fme22.12 (FM), Phaeoacremonium minimum Pm22.53 (PM) and Phaeomoniella chlamydospora Pc22.65 (PC). Pathogens were obtained from naturally Esca-affected ‘Nero di Troia’ vines cropped in Grumo Appula (Puglia region, Southern Italy). The antagonistic activity of each challenge organism was verified in a dual culture. TH and PO completely overgrew the three pathogens. Partial replacement characterized PE-FM, PE-PM, PE-PC and AA-PC interactions. Deadlock at mycelial contact was observed in AA-FM and AA-PM cultures. The calculated antagonism index (AI) indicated TH and PE as moderately active antagonists (10 < AI < 15), while AA and PO were weakly active (AI < 10). The maximum value of the re-isolation index (s) was associated with deadlock among AA-PM, AA-PC and PE-FM dual cultures. The tested biological limiters were always re-isolated when PO and TH completely replaced the three tested pathogens. TH and AA confirmed their efficiencies as biological limiters when inoculated on detached canes of ‘Nero di Troia’ in dual combination with FM, PC and PM. Nevertheless, additional experiments should be performed for a solid conclusion, along with validation experiments in the field. Full article

The dubas bug (Ommatissus lybicus) (Hemiptera: Tropiduchidae) is a serious pest in date palms in several date-producing countries, including Oman. Infestation results in a severe reduction in yield and a weakening of date palm growth. In addition, egg laying, which causes injuries to date palm leaves, results in the development of necrotic lesions on the leaves. This study aimed at investigating the role of fungi in the development of necrotic leaf spots following dubas bug infestation. Leaf samples developing leaf spot symptoms were collected from dubas-bug-infested leaves, as the leaf spot symptoms were not observed on the non-infested leaves. Isolation from date palm leaves collected from 52 different farms yielded 74 fungal isolates. Molecular identification of the isolates revealed that they belonged to 31 fungal species, 16 genera, and 10 families. Among the isolated fungi, there were five Alternaria species, four species each of Penicillium and Fusarium, three species each of Cladosporium and Phaeoacremonium, and two species each of Quambalaria and Trichoderma. Out of the thirty-one fungal species, nine were pathogenic on date palm leaves and induced varying levels of leaf spot symptoms. The pathogenic species were Alternaria destruens, Fusarium fujikuroi species complex, F. humuli, F. microconidium, Cladosporium pseudochalastosporoides, C. endophyticum, Quambalaria cyanescens, Phaeoacremonium krajdenii, and P. venezuelense, which were reported for the first time as leaf spot causal agents in date palms. The study provided novel information on the effect of dubas bug infestation in date palms on the development of fungal infection and associated leaf spot symptoms. Full article

Diesel spills in freshwater systems have adverse impacts on the water quality and the shore wetland. Microbial degradation is the major and ultimate natural mechanism that can clean the diesel from the environment. However, which, and how fast, diesel-degrading microorganisms could degrade spilled diesel has not been well-documented in river water. Using a combination of ¹⁴C-/³H--based radiotracer assays, analytical chemistry, MiSeq sequencing, and simulation-based microcosm incubation approaches, we demonstrated succession patterns of microbial diesel-degrading activities, and bacterial and fungal community compositions. The biodegradation activities of alkanes and polycyclic aromatic hydrocarbons (PAHs) were induced within 24 h after diesel addition, and reached their maximum after incubation for 7 days. Potential diesel-degrading bacteria Perlucidibaca, Acinetobacter, Pseudomonas, Acidovorax, and Aquabacterium dominated the community initially (day 3 and day 7), but later community structure (day 21) was dominated by bacteria Ralstonia and Planctomyces. The key early fungi responders were Aspergillus, Mortierella, and Phaeoacremonium by day 7, whereas Bullera and Basidiobolus dominated the fungal community at day 21. These results directly characterize the rapid response of microbial community to diesel spills, and suggest that the progression of diesel microbial degradation is performed by the cooperative system of the versatile obligate diesel-degrading and some general heterotrophic microorganisms in river diesel spills. Full article

Native strains of Trichoderma in vineyard soil represent an opportunity for reducing the incidence of grapevine trunk diseases (GTDs) in vineyards. Moreover, its relationship with the environment (physicochemical soil characteristics and farming management practices) remains unclear. In the current study, a survey was carried out on farming management used by viticulturists, and soil samples were studied to analyze their physicochemical properties and to isolate Trichoderma strains. Later, statistical analyses were performed to identify possible correlations between Trichoderma populations, soil management and soil characteristics. In addition, in vitro tests, including antibiosis and mycoparasitism, were performed to select those Trichoderma strains able to antagonize Phaeoacremonium minimum. In this study a positive correlation was found between the iron content and pH in the soil, and a lower pH increases Trichoderma populations in soils. Vineyard management also affects Trichoderma populations in the soil, negatively in the case of fertilization and tillage and positively in the case of herbicide spraying. Two Trichoderma native strains were selected as potential biocontrol agents (Trichoderma gamsii T065 and Trichoderma harzianum T087) using antibiosis and mycoparasitism as mechanisms of action. These results led to the conclusion that native Trichoderma strains hold great potential as biological control agents and as producers of secondary metabolites. Full article

In an olive orchard on the western part of Istria, Croatia, twig and branch dieback was observed on several olive trees. In total, seven samples from symptomatic trees were collected. Samples were analyzed, and four fungal isolates showed morphological similarities to the species Phaeoacremonium. One isolate, chosen as a representative, was taken for molecular identification and pathogenicity tests. Based on the DNA sequence data of the ITS, TUB, and EF1α gene regions, the isolate was identified as P. iranianum. Pathogenicity tests were conducted on detached olive branches and olive trees in the greenhouse. To the best of our knowledge, this is the first report of twig and branch dieback on olive caused by Phaeoacremonium iranianum. Full article

In recent years, there has been special interest in innovative technologies such as polymer melt or solution electrospinning, electrospraying, centrifugal electrospinning, coaxial electrospinning, and others. Applying these electrokinetic methods, micro- or nanofibrous materials with high specific surface area, high porosity, and various designs for diverse applications could be created. By using these techniques it is possible to obtain fibrous materials from both synthetic and natural biocompatible and biodegradable polymers, harmless to the environment. Incorporation of low-molecular substances with biological activity (e.g., antimicrobial, antifungal) is easily feasible. Moreover, biocontrol agents, able to suppress the development and growth of plant pathogens, have been embedded in the fibrous materials as well. The application of such nanotechnologies for the creation of plant protection products is an extremely promising new direction. This review emphasizes the recent progress in the development of electrospun fungicidal dressings and their potential to be applied in modern agriculture. Full article

Esca-affected vines alter the carbohydrate metabolism, xylem transport of water and photosynthesis and show regular grapes (but berries do not reach maturity), and phenolic compounds are reduced in concentration, oxidate and polymerizate. Pullulan and a mixture of scytalone and isosclerone (9:1; w/w), secondary metabolites produced in vitro and in planta by Phaeoacremonium minimum (syn. P. aleophilum) and Phaeomoniella chlamydospora, were assayed against the strains Byosal HS1 and IOC 18-2007 in microvinifications with synthetic grape must. The presence of pullulan and pentaketides mix affects the growth and metabolism of the tested Saccharomyces cerevisiae strains. Assays at 100 and 1000 µg mL⁻¹ inhibited the growth of both strains, while no effects were recorded when evaluated at 1 and 5 µg mL⁻¹. In comparison with the controls, pullulan and the scytalone/isosclerone mixture at 10 µg mL⁻¹ had a growth reduction, a lower alcohol yield, reduced the concentration of tartaric acid and malic acid; and slowed down the production of lactic acid, acetic acid and total polyphenol content of the tested S. cerevisiae strains. These metabolites could be applied as an alternative to the sulfite addition in the early stages of vinification to support the action of selected Saccharomyces. Appealing is the subtractive action of pullulan against tartaric acid. Further data are needed to confirm and validate the enological performance in freshly pressed grape juice. Full article

Fungi constitute the largest number of plant pathogens and are responsible for a range of serious plant diseases. Phaeomoniella chlamydospora (P. chlamydospora) and Phaeoacremonium aleophilum (P. aleophilum) are the main fungal pathogens causing esca disease in grapevines. On the other hand, there are beneficial microorganisms such as Trichoderma spp., which are able to control the growth of many phytopathogens. In the present study, innovative, eco-friendly hybrid nanomaterials were created by electrospinning PLLA, followed by the formation of a film of chitosan/Trichoderma asperellum (T. asperellum) spores on the fibers. The polymer carrier used in this study plays an active role in ensuring the viability of the biological agent during storage and, when placed in contact with moisture, ensures the agent’s normal development. Oligochitosan, as well as low molecular weight and high molecular weight chitosan, were used. The effects of chitosan molecular weight on the dynamic viscosity of chitosan solutions, film formation, mechanical properties, spore incorporation and growth were studied. The morphology of the prepared nanomaterials, and the presence of a film based on the formation of chitosan/T. asperellum spores on the PLLA fibers, were examined using scanning electron microscopy (SEM). The surface chemical compositions of the fibrous materials were studied using attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). The mechanical properties of the obtained materials were also tested. The microbiological screening that was performed revealed that the eco-friendly hybrid nanomaterials incorporated with the beneficial microorganism, T. asperellum, to hamper the growth of the pathogenic P. chlamydospora and P. aleophilum fungi. The suppression rate depended on the viscosity of the chitosan solution used for the film formation. The use of oligochitosan resulted in the most effective infection of the material with T. asperellum spores. The environmentally friendly hybrid nanomaterials obtained in this study—in which the bioagent was embedded—are promising bioactive dressings for protecting grapevines against esca disease. Full article

Grapevine trunk diseases (GTDs) pose a major threat to the wine industry worldwide. Currently, efficient biological methods or chemical compounds are not available for the treatment of infected grapevines. In the present study, we used an extract from the knotwood of spruce trees as a biological control against GTDs. Our in vitro trial was focused on the antifungal effects of the extract against the most common GTD pathogens—Cadophora luteo-olivacea, Dactylonectria torresensis, Diaporthe ampelina, Diaporthe bohemiae, Diplodia seriata, Eutypa lata, and Phaeoacremonium minimum. Our in vitro trial revealed a high antifungal effect of the extract against all tested fungi. The inhibition rates varied among the different species from 30% to 100% using 1 mg·mL⁻¹ extract. Subsequently, the efficiency of the extract was supported by an in planta experiment. Commercial grafts of Vitis vinifera were treated with the extract and planted. The total genomic DNA of grapevines was extracted 10 days and 180 days after the treatment. The fungal microbial diversities of the treated/untreated plants were compared using high-throughput amplicon sequencing (HTAS). Treated plants showed 76.9% lower relative abundance of the genus Diaporthe and 70% lower relative abundance of the genus Phaeoacremonium 10 days after treatment. A similar scenario was observed for the genus Cadophora 180 days after treatment, where treated plants showed 76% lower relative abundance of this genus compared with untreated grapevines. Full article

In this study, berry samples were collected from healthy (control) and symptomatic vines of the white varieties Viosinho and Malvasia-fina. Symptomatic vines showed two different degrees of severity at harvest, namely chlorotic and scorched leaves (severity level 1) and tiger stripe leaves (severity level 2). The total fatty acid content was reduced in both varieties and the total organic acid content was unchanged. The total free sugar content increased with symptom progression in Viosinho but remained unchanged in Malvasia-fina. Varietal differences were observed in the response of amino acids, whose levels increased in Malvasia-fina and decreased in Viosinho. Full article