Search Results (158)

Postharvest losses amongst small-scale farmers in developing countries are high due to inadequate resources and infrastructure. Among the various affected crops, tomatoes are particularly vulnerable; however, studies on postharvest losses of most fruits and vegetables are limited. Therefore, this study aimed to assess postharvest tomato losses under different production systems within the small-scale supply chain using the indirect assessment (questionnaires and interviews) and direct quantification of losses. Farmers reported tomato losses due to insects (82.35%), cracks, bruises, and deformities (70.58%), and diseases (64.71%). Chemical sprays were the main form of pest and disease control reported by all farmers. The direct quantification sampling data revealed that 73.07% of the tomatoes were substandard at the farm level, with 47.92% and 25.15% categorized as medium-quality and poor-quality, respectively. The primary contributors to the losses were decay (39.92%), mechanical damage (31.32%), and blotchiness (27.99%). Postharvest losses were significantly higher under open-field production systems compared to closed tunnels. The fungi associated with decay were mainly Geotrichum, Fusarium spp., and Alternaria spp. These findings demonstrate the main drivers behind postharvest losses, which in turn highlight the critical need for intervention through training and support, including the use of postharvest loss reduction technologies to enhance food security. Full article

Concerns about mycotoxin contamination by Alternaria spp. in tomato-based products emphasize the need for understanding the effect of the environment on their production. In the current study, we focused on three species frequently associated with tomato (A. alternata, A. solani, and A. tenuissima) by evaluating the effects of different temperatures (5 to 40 °C) and substrata (PDA and V8) on mycelial growth and the production of mycotoxins (alternariol, alternariol monomethyl ether, and tenuazonic acid). Both biological processes were supported between 5 and 35 °C, with optimal temperatures between 20 and 30 °C, depending on the species. Temperature and its interaction with species significantly (p < 0.05) affected both processes. However, the species factor alone was not significant (p > 0.05), indicating that environmental conditions affect Alternaria spp. growth and mycotoxin production more than the species itself does. Mathematical equations were developed to describe the effect of temperature on mycelial growth, as well as on the production of AOH, AME, and TeA, for each Alternaria species. High concordance (CCC ≥ 0.807) between observed and predicted data and low levels of residual error (RMSE ≤ 0.147) indicated the high goodness of fit of the developed equations, which may be used for the development of models to predict Alternaria contamination both in field and during post-harvest storage. Full article

The locoweeds Astragalus and Oxytropis in the Americas and China, as well as Swainsona in Australia, harbor swainsonine-producing endophytes responsible for “locoism” or “pea struck” syndromes in grazing animals. Demonstration of Alternaria section Undifilum spp. requires demonstration of morphological characters such as a wavy germ tube and slow growth. While Astragalus wetherilli, A. pubentissimus, Swainsona canescens, and S. galegifolia plants have been shown to contain swainsonine, and fungi isolated from the plants have been partially characterized genetically, the fungi have not been characterized morphologically. This work sought to complete morphological characterization and determine species for those fungi and from fungi associated with Swainsona luteola and S. brachycarpa. The fungi were isolated from their hosts onto media and exhibited slow growth, resulting in a colony diameter of approximately 10 mm after 30 days. Morphological identification revealed production of conidia that produced a wavy germ tube for the endophytes from Astragalus pubentissimus species, Swainsona canescens, and S. galegifolia. Sequence analyses of the ITS region and the swnK-KS and swnK-TR genes of these fungi suggest that the fungi isolated from Astragalus are closely related and distinct from the fungi isolated from Swainsona. Presence of the swnK gene demonstrates that all the fungi have a necessary component to produce swainsonine. Fungi isolated from Astragalus spp. differed in color, growth, and conidium size, and/or their sequences. While the fungi isolated from Swainsona canescens and S. galegifolia endophytes differed in color, growth, and conidium size, those isolated from Swainsona luteola and S. brachycarpa did not produce conidia. Sequences from all Swainsona endophytes were almost identical and were concluded to be the same species. The new species described here are Alternaria wetherii, A. pubentissima, A. pubentissimoides, and A. swainsonii. Full article

Several species of Fusarium are reported to infect inflorescences of high-THC-containing cannabis (Cannabis sativa L.) plants grown in greenhouses in Canada. These include F. graminearum, F. sporotrichiodes, F. proliferatum, and, to a lesser extent, F. oxysporum and F. solani. The greatest concern surrounding the infection of cannabis by these Fusarium species, which cause symptoms of bud rot, is the potential for the accumulation of mycotoxins that may go undetected. In the present study, both naturally infected and artificially infected inflorescence tissues were tested for the presence of fungal-derived toxins using HPLC-MS/MS analysis. Naturally infected cannabis tissues were confirmed to be infected by both F. avenaceum and F. graminearum using PCR. Pure cultures of these two species and F. sporotrichiodes were inoculated onto detached inflorescences of two cannabis genotypes, and after 7 days, they were dried and assayed for mycotoxin presence. In these assays, all Fusarium species grew prolifically over the tissue surface. Tissues infected by F. graminearum contained 3-acetyl DON, DON, and zearalenone in the ranges of 0.13–0.40, 1.18–1.91, and 31.8 to 56.2 μg/g, respectively, depending on the cannabis genotype. In F. sporotrichiodes-infected samples, HT2 and T2 mycotoxins were present at 13.9 and 10.9 μg/g in one genotype and were lower in the other. In F. avenaceum-inoculated tissues, the mycotoxins enniatin A, enniatin A1, enniatin B, and enniatin B1 were produced at varying concentrations, depending on the isolate and cannabis genotype. Unexpectedly, these tissues also contained detectable levels of 3-acetyl DON, DON, and zearalenone, which was attributed to apre-existing natural infection by F. graminearum that was confirmed by RT-qPCR. Beauvericin was detected in tissues infected by F. avenaceum and F. sporotrichiodes, but not by F. graminearum. Naturally infected, dried inflorescences from which F. avenaceum was recovered contained beauvericin, enniatin A1, enniatin B, and enniatin B1 as expected. Uninoculated cannabis inflorescences were free of mycotoxins except for culmorin at 0.348 μg/g, reflecting pre-existing infection by F. graminearum. The mycotoxin levels were markedly different between the two cannabis genotypes, despite comparable mycelial colonization. Tall fescue plants growing in the vicinity of the greenhouse were shown to harbor F. avenaceum and F. graminearum, suggesting a likely external source of inoculum. Isolates of both species from tall fescue produced mycotoxins when inoculated onto cannabis inflorescences. These findings demonstrate that infection by F. graminearum and F. avenaceum, either from artificial inoculation or natural inoculum originating from tall fescue plants, can lead to mycotoxin accumulation in cannabis inflorescences. However, extensive mycelial colonization following prolonged incubation of infected tissues under high humidity conditions is required. Inoculations with Penicillium citrinum and Aspergillus ochraceus under these conditions produced no detectable mycotoxins. The mycotoxins alternariol and tentoxin were detected in several inflorescence samples, likely as a result of natural infection by Alternaria spp. Fusarium avenaceum is reported to infect cannabis inflorescences for the first time and produces mycotoxins in diseased tissues. Full article

Plant–endophyte symbioses are widespread in grasslands. While symbiotic interactions often provide hosts with major fitness enhancements, the role of the endophyte Alternaria oxytropis, which produces swainsonine in locoweeds (Oxytropis and Astragalus spp.), remains enigmatic. We compared endophyte-infected (E+) and endophyte-free (E−) plants of three main Chinese locoweed species (O. kansuensis, O. glabra, and O. ochrocephala) under controlled conditions, and analyzed environmental factors at locoweed poisoning hotspots for herbivores. The results demonstrated significant species-specific effects: E+ plants of O. glabra and O. ochrocephala exhibited 26–39% reductions in biomass, net photosynthetic rate, and stomatal conductance, with elevated CO₂ levels, while O. kansuensis showed no measurable impacts. Swainsonine concentrations were 16–20 times higher in E+ plants (122.6–151.7 mg/kg) than in E− plants. Geospatial analysis revealed that poisoning hotspots for herbivores consistently occurred in regions with extreme winter conditions (minimum temperatures ≤ −17 °C and precipitation ≤ 1 mm during the driest month), suggesting context-dependent benefits under abiotic stress. These findings suggest that the ecological role of A. oxytropis may vary depending on both host species and environmental context, highlighting a trade-off between growth costs and potential stress tolerance conferred by A. oxytropis. The study underscores the need for field validation to elucidate the adaptive mechanisms maintaining this symbiosis in harsh environments. Full article

Strawberry black spot, caused by Alternaria spp., is an emerging disease that threatens both leaves and fruits during strawberry growth and postharvest storage. This study investigated the boscalid sensitivity of 49 Alternaria isolates collected from symptomatic strawberry leaves. Boscalid has been widely used to control diseases in strawberry in China for several years. The EC₅₀ values for the tested isolates ranged from 0.0884 to 266.3289 µg/mL, indicating that most isolates exhibited varying levels of resistance to boscalid based on resistance ratio values. A substitution of SDHC-H134R was detected from most high-resistance isolates. Fitness cost assessment revealed that highly resistant isolates had a reduced conidial germination rate; however, their mycelial growth and conidia production were increased. No significant virulence deficiency was observed, suggesting low fitness cost in resistant isolates. Furthermore, the highly resistant isolates exhibited positive cross-resistance to fluopyram and fluxapyroxad. Molecular docking analysis revealed that the SDHC-H134R mutation reduced the binding affinity between boscalid and mitochondrial complex II. These findings suggest that resistance management strategies, such as fungicide rotation or combinations of fungicides with different action modes, should be implemented to control strawberry diseases, minimizing the development of fungicide resistance and improving overall disease control efficacy. Full article

The purpose of this study was to investigate the growth-promoting effects of four rhizobacterial isolates (RS60, RS65, RS46, and RP6) isolated from the tomato rhizosphere. These isolates were screened for key plant growth-promoting rhizobacteria (PGPR) mechanisms, including ammonia production, nitrogen fixation, phosphate solubilization, indole-3-acetic acid (IAA) production, and siderophore synthesis. Their potential to enhance seed germination and tomato plant growth was investigated in controlled and greenhouse conditions. Four isolates exhibited multiple PGPR attributes, notably IAA and ammonia production as well as phosphate solubilization. The results revealed that these strains significantly enhanced tomato seed germination and shoot growth in vitro, with RS65 showing the highest germination rate (70%). However, no significant differences in early seedling responses were observed under greenhouse conditions when compared to the control. Thirty days after inoculation, greenhouse results revealed that the four studied strains significantly increased growth metrics including shoot length, number of leaves, collar diameter, and dry weight. The isolate RP6 showed a significant effect on the growth of the plant, with an average shoot length of 34.40 cm and nine leaves per plant. In vitro antagonism assays demonstrated that isolates RS60, RS65, and RP6 effectively inhibited the growth of Botrytis cinerea, Alternaria alternata, and Oidium lycopersici, with inhibition rates exceeding 65%. These antagonistic activities were linked to the production of hydrolytic enzymes (chitinase, cellulase, pectinase, protease), siderophores, and hydrogen cyanide (HCN). Molecular identification through 16S rRNA gene sequencing confirmed the isolates as Bacillus cereus (RS60), Bacillus pumilus (RS46), Bacillus amyloliquefaciens (RP6), and Bacillus velezensis (RS65), each showing over 97% sequence similarity with reference strains. These findings underscore the potential of the selected Bacillus spp. as promising biofertilizers and biocontrol agents for sustainable tomato cultivation and support their inclusion in integrated disease and nutrient management strategies. Full article

Type I allergies are triggered by immunoglobulin E (IgE)-mediated hypersensitivity reactions upon allergen exposure. Dogs are diagnosed with allergic dermatitis based on history, clinical signs, and allergen-specific IgE detection. Using the multiple allergen simultaneous test (MAST)–immunoblot assay, this study measured IgE concentrations and analyzed the proportion of dogs showing allergen-specific IgE positivity, and IgE concentrations of environmental and food allergens in South Korea. We examined data from canine serum using the MAST assay in 2023; the allergen panel included 130 allergens. Data were analyzed, with results greater than zero regarded as positive for the prevalence measurements and concentrations compared among subgroups. Overall, 2663 samples were evaluated to assess the proportion of dogs showing allergen-specific IgE positivity and mean concentrations of environmental and food allergens. Among the environmental allergens, Alternaria spp. had the highest IgE prevalence, whereas Japanese cedar had the highest mean IgE concentration. Allergen-specific differences were observed among subgroups categorized by age, sex, and breed. To our knowledge, this research is the first large-scale study to analyze canine serum using a MAST assay to assess the IgE prevalence of allergen-specific IgE positivity and concentration and to examine data by age, sex, and breed. These findings provide information for diagnosis and management of canine allergies. Full article

Early blight, caused by fungi of the genus Alternaria, is one of the most destructive diseases affecting tomato plants, leading to a decrease in yield and commercial value. Studies so far on Alternaria spp. affecting tomato in Kazakhstan have been limited to morphological identification or molecular analysis, without an in-depth phylogenetic study and pathogenicity assessment. In this study, between 2023 and 2024, 61 isolates were obtained from tomato leaves with early blight symptoms and identified, based on conidial morphology and DNA sequencing, as A. tenuissima (54%) and A. alternata (46%). The pathogenicity assessment showed that the disease index for A. tenuissima was 21.7–53.3, while it was 41.7–60.0 for A. alternata, indicating greater aggressiveness of the latter species. The disease index varied by region, with the highest average value recorded for A. alternata from Almaty (55.7%), while 38.2% and 36.2% for A. tenuissima were recorded from Pavlodar and Akmola, respectively. Both species showed notable intraspecific variation in pathogenicity. To our knowledge, this is the first reported case of A. tenuissima detection as the causative agent of early blight in tomato plants in Kazakhstan. The results of this study may help facilitate the development of effective disease management strategies. Full article

Edible flowers have been used since ancient times directly as food, flavoring agents, and garnish in food products, and are now reappearing in modern cuisine. Edible flowers have gained popularity due to changing consumer habits focused on healthier food options. In addition to contributing to the esthetics and flavor of various dishes, edible flowers are now recognized for their nutritional value, as they contain bioactive components with different health benefits. However, a significant concern regarding edible flowers is the potential contamination by undesirable microorganisms. Since edible flowers are often consumed fresh or minimally processed, they can pose a microbiological risk. Edible flowers may be susceptible to contamination by various pathogenic microorganisms, particularly Bacillus spp., Enterobacter spp., Salmonella spp., and Staphylococcus aureus. In addition, mycotoxin-producing fungi, such as Aspergillus, Penicillium, Alternaria, or Fusarium, can be found in various flowers. Good agricultural practices, hygienic handling, and appropriate storage are essential to reduce contamination and guarantee the safe consumption of edible flowers. Since current investigations on the microbiological safety aspects of edible flowers are scarce, this review aims to provide an overview of the consumption of edible flowers and a discussion of their uses, health benefits, and risks, focusing on microbiological aspects. Full article

To manage the developing resistance of Alternaria spp. [the causal fungi of ginseng Alternaria leaf and stem blight (GALSB)] to QoIs fungicides, the toxicity and biochemical activity of pyrimidine nucleoside antibiotics (PNA) against Alternaria spp., cross-resistance between PNA and eight other fungicides currently used to control GALSB disease, and the efficacy of PNA for controlling GALSB in vitro and in vivo were investigated. The distributions of EC₅₀ values of PNA against the mycelial growth (115 isolates) and conidia germination (89 isolates) of A. alternata were unimodal, with mean EC₅₀ values of 10.192 ± 4.961 μg/mL and 0.828 ± 0.101 μg/mL, respectively. There were no significant correlations between the sensitivity of A. alternata to PNA and eight other fungicides (p < 0.05). PNA caused morphological changes in A. alternata mycelia and germ tubes, increased cell membrane permeability, and reduced intracellular DNA and protein levels. On detached ginseng leaves, 300 μg/mL PNA achieved mean protective and curative effects of 87.93% and 94.77% against A. alternata 7 days post-inoculation, outperforming that of 300 μg/mL kresoxim-methyl. Field trial results showed that PNA (180 g a.i./hm²) achieved mean efficacies of 85.63%, 84.07%, and 72.55% at three sites 7, 15, and 30 days after the last spray, which were 5.28–37.74% higher than those of control fungicides pyraclostrobin, azoxystrobin, and kresoxim-methyl at corresponding time points. Overall, our findings indicate that PNA are effective agents for the management of Alternaria spp. resistance to QoIs fungicides. Full article

The soybean [Glycine max (L.) Merr.] plays an important role in human and animal nutrition due to its high protein and oil content. The present study was undertaken to determine the effect of different mineral nitrogen (N) rates and inoculation with Bradyrhizobium japonicum bacteria on fungal colonization of the anatomical parts of seeds (APSS) of two soybean cultivars (Aldana and Annushka). Fungi were identified with the use of the macroscopic method and the polymerase chain reaction (PCR) assay. The study demonstrated that fungal colonization was higher on soybeans cv. Annushka than cv. Aldana. The obtained results indicate that fungal colonization intensity was highest in the cotyledons, lower in the seed coat, and lowest in the embryonic axis. The APSS were colonized by pathogenic fungi belonging mostly to the genus Fusarium, as well as saprotrophic fungi represented by Alternaria alternata, Cladosporium cladosporioides, Penicillium spp., and Rhizopus nigricans. Fungal colonization intensity was highest in soybean seeds inoculated with HiStick^®Soy and in control seeds, whereas the number of fungal isolates obtained from the APSS was lower in the remaining treatments: 60 kg N ha⁻¹ + HiStick^®Soy, 30 kg N ha⁻¹ + HiStick^®Soy, Nitragina, and 60 kg N ha⁻¹. In addition, the statistical analysis revealed that fungal abundance and the biodiversity indicators of fungal communities, including relative frequency (Rf), dominance (Y), and species richness (S), differed across the analyzed APSS and years of the study, which indicates that these parameters were significantly influenced by weather conditions. The abundance of pathogenic and saprotrophic fungal species did not differ significantly between the examined soybean cultivars. Spearman’s rank correlation coefficients were calculated to assess the strength of the relationship between weather conditions and the diversity of fungal communities colonizing soybean seeds. The analysis revealed that the development of pathogenic fungi on soybean seeds was determined by temperature and precipitation on 11–30 June and 1–10 August, whereas the prevalence of saprotrophic fungi was influenced only by precipitation on 1–10 and 21–30 July and 1–10 August. The qPCR analysis demonstrated that the colonization of soybean seeds by F. graminearum and P. verrucosum was affected by all experimental factors. Full article

Alternaria is a genus that contains several important plant pathogens affecting nearly 400 plant species worldwide, including economically important crops such as grapes, citrus, and ornamental plants. Rapid, scalable, and efficient methods of pathogen detection are crucial for managing plant diseases and ensuring agricultural productivity. Current amplicon sequencing protocols for Alternaria detection often require the enzymatic barcoding of amplicons, increasing hands-on time, cost, and contamination risk. We present a proof-of-concept study using custom barcoded primers, combining universal primers targeting ITS1 and ITS2 regions (600 bp) coupled with Oxford Nanopore Technologies (ONT) barcode sequences. Sequencing was performed on infected grapevine, mandarin orange, thuja, and maple tree samples. In total, we analyzed 38 samples using qPCR; 8 tested positive for Alternaria, which were sequenced using a newly developed protocol. As a result, we could identify Alternaria in every positive sample, and besides the pathogen of interest, we could identify the associated mycobiome. This protocol reduces hands-on time and cost, making a significant advancement over current sequencing methods. Future work will focus on optimizing our approach for high-throughput sequencing of up to 96 samples and determining the method’s applicability for large-scale mycobiome analysis. Full article

Figs are highly perishable, with significant losses due to overripening or failure to meet market standards. Drying is essential to extending their shelf life and reducing food waste. This study evaluated the impact of traditional sun drying and hybrid solar drying on the quality of dried “Pingo de Mel” figs. Sun drying required 5–7 days, while the hybrid solar drying completed the process in 3 days. Both methods resulted in a similar final moisture content (29.43% and 28.14%, respectively), water activity (0.68 and 0.63, respectively), and hardness (2.36 and 2.61 N, respectively). Hybrid solar-dried figs exhibited slightly lower L* values and higher b* values, reflecting a darker appearance with a more pronounced yellow hue. Fresh and sun-dried figs developed fungal growth (Alternaria spp., Aspergillus niger, Cladosporium spp., and Fusarium spp.) within four weeks, while hybrid solar-dried figs remained contamination-free, improving microbial safety. Moreover, hybrid drying preserved higher levels of phenolic compounds, particularly rutin and 5-O-caffeoylquinic acid, along with greater antioxidant activity. Overall, hybrid solar drying offers significant advantages over traditional sun drying by reducing the drying time, enhancing microbial safety, and preserving bioactive compounds, making it a more effective method for fig preservation. Full article

Mycotoxins are naturally occurring secondary metabolites produced by specific fungal strains. They can cause adverse effects, posing a serious health threat to both humans and livestock. Focusing on several mycotoxins, this study first aimed at optimizing and validating an ultra-high liquid chromatography-tandem mass spectrometry quantification method. This method was then applied to evaluate the production of the targeted mycotoxins in maize cultivated in the presence of Aspergillus spp., Fusarium spp., and Alternaria spp. The limits of detection of the analytical method for the different mycotoxins ranged between 0.5 and 200 μg kg⁻¹, while the limits of quantification were between 1 and 400 μg kg⁻¹. The linearities of the calibration curves were evaluated, with calculated R² values above 0.99. The mean recoveries fell within the acceptable range of 74.0–106.0%, the repeatability was not higher than 14.4% RSD, and the highest intra-laboratory reproducibility was 16.2% RSD. The expanded measurement uncertainties ranged between 4.0% and 54.7%. Several fungal strains cultivated on maize grains were demonstrated to produce the targeted toxins, with production at µg kg⁻¹ to mg kg⁻¹ levels for aflatoxins and up to g kg⁻¹ levels for fumonisins, zearalenone, and alternariol. Full article