RESUMEN

Aedes aegypti transmits the arboviruses that cause dengue, zika, and chikungunya. Entomopathogenic fungi are beneficial microorganisms that can be incorporated into current strategies against mosquitoes of public health concern. This study molecularly identified the Metarhizium anisopliae CG 153 isolate and evaluated its virulence against larvae, pupae, and adults (both males and females) of Ae. aegypti. Different concentrations of conidia were used (1 × 104-8 conidia mL-1). Larval and pupal survival was monitored daily for seven and three days, respectively, while adults were monitored for 15 days. The efficacy of M. anisopliae sensu stricto was concentration-dependent, with higher concentrations achieving better results, demonstrating greater virulence against larval and adult stages of Ae. aegypti. The fungus reduced the larval survival by 95,5% (1 × 108 con.mL-1), 94,4% (1 × 107 con.mL-1), 78,9% (1 × 106 con.mL-1), 62,2% (1 × 105 con.mL-1), and 41,1% (1 × 104 con.mL-1) after seven days. Adults also showed susceptibility to the fungus, with no observed difference in susceptibility between males and females. Over 15 days of monitoring, adult survival rates ranged from approximately 6.7% to 72%. Pupae exhibited lower susceptibility to the fungus across different concentrations, with survival rates ranging from approximately 87.8% to 100%. This study highlights the high effectiveness of M. anisopliae CG 153 against both Ae. aegypti larvae and adults (male and female) under controlled conditions, suggesting its promising potential for further evaluation and application in field conditions.

Asunto(s)

Aedes , Larva , Metarhizium , Control Biológico de Vectores , Pupa , Animales , Aedes/microbiología , Femenino , Masculino , Larva/microbiología , Pupa/microbiología , Virulencia , Control de Mosquitos/métodos , Esporas Fúngicas

RESUMEN

Arbuscular mycorrhizal (AM) fungi can sequester different potentially toxic elements, such as trace elements (TEs), within their structures to alleviate the toxicity for its host plant and themselves. To elucidate the role of AM fungi in TEs immobilization in the rhizosphere of host plants, it is important to know the TEs distribution in AM fungal structures. In the present study, we investigated the distribution and concentration of TEs within extraradical spores and mycelium of the AM fungus Rhizophagus intraradices, collected from the rhizosphere of Senecio bonariensis plants grown in a soil polluted with multiple TEs, by using Particle-Induced X-ray Emission with a micro-focused beam (micro PIXE). This technique enabled the simultaneous micrometric mapping of elements in a sample. The calculated values were compared with those in the polluted substrate, measured by the Wavelength Dispersive X-ray Fluorescence technique. The highest concentrations of Fe, P, Ti, Mn, Cr, Cu and Zn were found in AM fungal spores, where they were accumulated, while extraradical mycelium was enriched in Cu. Finally, we demonstrated that AM fungi can simultaneously accumulate high amounts of different TEs in their structures, thus reducing the toxicity of these elements to its host plant.

Asunto(s)

Glomeromycota , Micorrizas , Espectrometría por Rayos X , Oligoelementos , Oligoelementos/análisis , Oligoelementos/metabolismo , Micorrizas/química , Micorrizas/metabolismo , Glomeromycota/química , Rizosfera , Esporas Fúngicas/química , Esporas Fúngicas/crecimiento & desarrollo , Micelio/química , Micelio/crecimiento & desarrollo , Micelio/metabolismo , Microbiología del Suelo , Raíces de Plantas/microbiología

RESUMEN

The advancement of fungal biocontrol agents depends on replacing cereal grains with low-cost agro-industrial byproducts for their economical mass production and development of stable formulations. We propose an innovative approach to develop a rice flour-based formulation of the beneficial biocontrol agent Trichoderma asperelloides CMAA1584 designed to simulate a micro-bioreactor within the concept of full biorefinery process, affording in situ conidiation, extended shelf-life, and effective control of Sclerotinia sclerotiorum, a devastating pathogen of several dicot agricultural crops worldwide. Rice flour is an inexpensive and underexplored byproduct derived from broken rice after milling, capable of sustaining high yields of conidial production through our optimized fermentation-formulation route. Conidial yield was mainly influenced by nitrogen content (0.1% w/w) added to the rice meal coupled with the fermentor type. Hydrolyzed yeast was the best nitrogen source yielding 2.6 × 109 colony-forming units (CFU)/g within 14 days. Subsequently, GControl, GLecithin, GBreak-Thru, GBentonite, and GOrganic compost+Break-Thru formulations were obtained by extrusion followed by air-drying and further assessed for their potential to induce secondary sporulation in situ, storage stability, and efficacy against Sclerotinia. GControl, GBreak-Thru, GBentonite, and GOrganic compost+Break-Thru stood out with the highest number of CFU after sporulation upon re-hydration on water-agar medium. Shelf-life of formulations GControl and GBentonite remained consistent for > 3 months at ambient temperature, while in GBentonite and GOrganic compost+Break-Thru formulations remained viable for 24 months during refrigerated storage. Formulations exhibited similar efficacy in suppressing the myceliogenic germination of Sclerotinia irrespective of their concentration tested (5 × 104 to 5 × 106 CFU/g of soil), resulting in 79.2 to 93.7% relative inhibition. Noteworthily, all 24-month-old formulations kept under cold storage successfully suppressed sclerotia. This work provides an environmentally friendly bioprocess method using rice flour as the main feedstock to develop waste-free granular formulations of Trichoderma conidia that are effective in suppressing Sclerotinia while also improving biopesticide shelf-life. KEY POINTS: • Innovative "bioreactor-in-a-granule" system for T. asperelloides is devised. • Dry granules of aerial conidia remain highly viable for 24 months at 4 °C. • Effective control of white-mold sclerotia via soil application of Trichoderma-based granules.

Asunto(s)

Ascomicetos , Reactores Biológicos , Fermentación , Oryza , Esporas Fúngicas , Reactores Biológicos/microbiología , Ascomicetos/crecimiento & desarrollo , Ascomicetos/metabolismo , Oryza/microbiología , Esporas Fúngicas/crecimiento & desarrollo , Nitrógeno/metabolismo , Hypocreales/metabolismo , Hypocreales/crecimiento & desarrollo , Agentes de Control Biológico/química , Trichoderma/metabolismo , Trichoderma/crecimiento & desarrollo , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/prevención & control

RESUMEN

Fusarioid fungi, particularly Neocosmospora solani and Fusarium oxysporum, are emerging as significant human pathogens, causing infections ranging from localized mycoses to life-threatening systemic diseases. Accurate identification and preservation of these fungi in clinical laboratories remain challenging because of their diverse morphologies and specific growth requirements. This study evaluated a novel milk-honey and malt agar (MHM) against conventional media for cultivating and preserving 60 clinical fusarioid isolates, including Neocosmospora spp. (n = 47), Bisifusarium spp. (n = 5), and Fusarium spp. (n = 8). Compared with Sabouraud dextrose 2 % agar (SDA) and malt extract agar (ME2), MHM significantly increased conidia production (p < 0.0001, mean = 3.4 × 103, standard deviation (SD) = ±1.3 × 103), with results similar to those of carnation leaf agar (CLA). MHM facilitated superior preservation of fusarioid viability for up to one year at room temperature on slant cultures and over two years on swabs in Amies gel with charcoal, outperforming current methods such as Castellani (water) or cryopreservation. Morphological characterization of fusarioid fungi grown on MHM revealed distinct growth patterns and conidial structures for Neocosmospora, Bisifusarium, and Fusarium species, aiding in identifying these genera. The superior performance of MHM in stimulating conidiation, maintaining viability, and preserving morphology underscore its potential as a reference medium for medically relevant fusarioid fungi, with broad implications for clinical mycology laboratories and resource-limited settings.

Asunto(s)

Agar , Medios de Cultivo , Fusarium , Medios de Cultivo/química , Fusarium/aislamiento & purificación , Fusarium/crecimiento & desarrollo , Fusarium/clasificación , Humanos , Preservación Biológica/métodos , Esporas Fúngicas/crecimiento & desarrollo , Esporas Fúngicas/aislamiento & purificación , Fusariosis/microbiología , Hongos/aislamiento & purificación , Hongos/clasificación , Hongos/crecimiento & desarrollo , Fenotipo

RESUMEN

Pseudohydnum, commonly known as cat's tongue mushrooms, is a monophyletic assemblage within Auriculariales, which encompasses species with gelatinous basidiomata, spathulate, flabellate, or shell-shaped pileus, hydnoid hymenophore, globose to ellipsoidal basidiospores, and longitudinally cruciate-septate basidia. According to the available literature, 16 species have been described in Pseudohydnum, mostly represented in temperate-boreal forests of the Northern Hemisphere. However, the limited morphological, molecular, and ecological information, especially from the Southern Hemisphere ecosystems, does not presently allow a reliable assessment of its taxonomic boundaries nor provide a complete picture of the species diversity in the genus. In an ongoing effort to examine specimens collected in dense and mixed ombrophilous forest fragments (Atlantic Rainforest domain) from Southeastern and Southern Brazil, additional taxa assigned to Pseudohydnum were identified. Four new species are recognized based mostly on characters of the pileus surface, stipe, hymenium, and basidiospores. Molecular phylogenetic analyses based on nuc rDNA internal transcribed spacer region ITS1-5.8S-ITS2 (ITS barcode), partial nuc rDNA 28S, and partial RNA polymerase II largest subunit (RPB1) sequences supported the description of these new taxa. Here, we propose Pseudohydnum brasiliense, P. brunneovelutinum, P. cupulisnymphae, and P. viridimontanum as new species. Morphological descriptions, line drawings, habitat photos, and comparisons with closely related taxa are provided. A dichotomous key for identification of currently known Southern Hemisphere Pseudohydnum species is presented.

Asunto(s)

Agaricales , ADN de Hongos , ADN Espaciador Ribosómico , Filogenia , Esporas Fúngicas , ADN de Hongos/genética , Brasil , ADN Espaciador Ribosómico/genética , Esporas Fúngicas/citología , Esporas Fúngicas/clasificación , Agaricales/clasificación , Agaricales/genética , Agaricales/aislamiento & purificación , Agaricales/citología , Análisis de Secuencia de ADN , ADN Ribosómico/genética , Basidiomycota/clasificación , Basidiomycota/genética , Basidiomycota/citología , Basidiomycota/aislamiento & purificación , ARN Ribosómico 28S/genética , Cuerpos Fructíferos de los Hongos/citología , Bosques

RESUMEN

Aspergillus fumigatus causes aspergillosis and relies on asexual spores (conidia) for initiating host infection. There is scarce information about A. fumigatus proteins involved in fungal evasion and host immunity modulation. Here we analysed the conidial surface proteome of A. fumigatus, two closely related non-pathogenic species, Aspergillus fischeri and Aspergillus oerlinghausenensis, as well as pathogenic Aspergillus lentulus, to identify such proteins. After identifying 62 proteins exclusively detected on the A. fumigatus conidial surface, we assessed null mutants for 42 genes encoding these proteins. Deletion of 33 of these genes altered susceptibility to macrophage, epithelial cells and cytokine production. Notably, a gene that encodes a putative glycosylasparaginase, modulating levels of the host proinflammatory cytokine IL-1ß, is important for infection in an immunocompetent murine model of fungal disease. These results suggest that A. fumigatus conidial surface proteins are important for evasion and modulation of the immune response at the onset of fungal infection.

Asunto(s)

Aspergilosis , Aspergillus fumigatus , Proteínas Fúngicas , Evasión Inmune , Proteoma , Esporas Fúngicas , Aspergillus fumigatus/inmunología , Aspergillus fumigatus/genética , Animales , Esporas Fúngicas/inmunología , Ratones , Proteoma/genética , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Proteínas Fúngicas/inmunología , Aspergilosis/inmunología , Aspergilosis/microbiología , Humanos , Interacciones Huésped-Patógeno/inmunología , Interacciones Huésped-Patógeno/genética , Macrófagos/inmunología , Macrófagos/microbiología , Macrófagos/metabolismo , Citocinas/metabolismo , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Proteínas de la Membrana/inmunología , Modelos Animales de Enfermedad , Células Epiteliales/microbiología , Células Epiteliales/inmunología , Células Epiteliales/metabolismo , Femenino

RESUMEN

The search for less harmful, ecologically efficient, more specific, and natural alternatives for the control of pathogens is essential. Bauhinia variegata lectin (BvL) is a protein that has numerous biological activities, including antifungal. The present study examines the potential in vitro of B. variegata lectin against the fungus Bipolaris oryzae, responsible for agricultural losses in southern Brazil, due to damage to rice fields during seed germination. Bioassays to assess the inhibition potential of BvL were performed, including fungal growth, spore formation, and germination, in concentrations of 0, 25, 50, and 100 µg mL-1. Only the concentration of 100 µg mL-1 successfully inhibited mycelial growth and spore germination, while in spore formation, all treatments inhibited sporulation. In addition, fluorescence microscopy analysis demonstrated the ability of lectin to bind to the fungus and the lack of detection in the presence of lactose, suggesting its interaction with the fungal cell wall structures. This study highlights the potential of B. variegata seed lectin to control mycelial growth, sporulation, and germination of the phytopathogenic fungus B. oryzae, posing as a new biotechnological possibility for biological control.

Asunto(s)

Antifúngicos , Bauhinia , Lectinas de Plantas , Esporas Fúngicas , Bauhinia/química , Esporas Fúngicas/efectos de los fármacos , Esporas Fúngicas/crecimiento & desarrollo , Antifúngicos/farmacología , Antifúngicos/química , Lectinas de Plantas/farmacología , Ascomicetos/efectos de los fármacos , Ascomicetos/crecimiento & desarrollo , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/prevención & control , Lectinas/farmacología , Oryza/microbiología , Oryza/crecimiento & desarrollo , Micelio/efectos de los fármacos , Micelio/crecimiento & desarrollo , Brasil , Semillas/efectos de los fármacos

RESUMEN

A new and threatened polypore species, Bondarzewia loguerciae, is described from the cloud forests of southern Brazil. It is characterized by single-pileate basidiomata that grow on dead branches and along living stems of standing trunks and present a context with dark lines and resinous tubes. When growing in axenic culture, this species also develops chlamydospores. We provide an illustrated morphological description and molecular analysis. Our specimens from Brazil form a monophyletic group among other species of the Southern Hemisphere. The conservation status of B. loguerciae is assessed and published as "Critically Endangered" based on the International Union for Conservation of Nature  (IUCN) criteria. Additionally, a key to the species is provided.

Asunto(s)

ADN de Hongos , Especies en Peligro de Extinción , Bosques , Filogenia , Esporas Fúngicas , Brasil , ADN de Hongos/genética , Esporas Fúngicas/citología , ADN Espaciador Ribosómico/genética , Análisis de Secuencia de ADN

RESUMEN

Species of the ectomycorrhizal (ECM) family Cortinariaceae (Agaricales, Agaricomycetes, Basidiomycota) have long been considered impoverished or absent from lowland tropical rainforests. Several decades of collecting in forests dominated by ECM trees in South America's Guiana Shield is countering this view, with discovery of numerous Cortinariaceae species. To date, ~12 morphospecies of this family have been found in the central Pakaraima Mountains of Guyana. Here, we describe three of these as new species of Cortinarius and two as new species of Phlegmacium from forests dominated by the ECM tree genera Dicymbe (Fabaceae subfam. Detarioideae), Aldina (Fabaceae subfam. Papilionoideae), and Pakaraimaea (Cistaceae). Macromorphological, micromorphological, habitat, and DNA sequence data are provided for each new species.

Asunto(s)

Agaricales , ADN de Hongos , Fabaceae , Micorrizas , Filogenia , Guyana , ADN de Hongos/genética , Micorrizas/clasificación , Micorrizas/genética , Agaricales/clasificación , Agaricales/genética , Agaricales/aislamiento & purificación , Fabaceae/microbiología , Análisis de Secuencia de ADN , ADN Espaciador Ribosómico/genética , Cortinarius/clasificación , Cortinarius/genética , Cortinarius/aislamiento & purificación , Ecosistema , ADN Ribosómico/genética , Esporas Fúngicas/citología , Esporas Fúngicas/clasificación

RESUMEN

The present study investigates the interactions between eight glucosinolate hydrolysis products (GHPs) sourced from broccoli by-products and the detoxifying enzymes of Botrytis cinerea, namely eburicol 14-alpha-demethylase (CYP51) and glutathione-S-transferase (GST), through in silico analysis. Additionally, in vitro assays were conducted to explore the impact of these compounds on fungal growth. Our findings reveal that GHPs exhibit greater efficacy in inhibiting conidia germination compared to mycelium growth. Furthermore, the results demonstrate the antifungal activity of glucosinolate hydrolysis products derived from various parts of the broccoli plant, including inflorescences, leaves, and stems, against B. cinerea. Importantly, the results suggest that these hydrolysis products interact with the detoxifying enzymes of the fungus, potentially contributing to their antifungal properties. Extracts rich in GHPs, particularly iberin and indole-GHPs, derived from broccoli by-products emerge as promising candidates for biofungicidal applications, offering a sustainable and novel approach to plant protection by harnessing bioactive compounds from agricultural residues.

Asunto(s)

Antifúngicos , Botrytis , Brassica , Glucosinolatos , Botrytis/efectos de los fármacos , Glucosinolatos/química , Glucosinolatos/farmacología , Glucosinolatos/metabolismo , Brassica/microbiología , Hidrólisis , Antifúngicos/farmacología , Antifúngicos/química , Esporas Fúngicas/efectos de los fármacos , Esporas Fúngicas/crecimiento & desarrollo , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/prevención & control , Simulación del Acoplamiento Molecular , Pruebas de Sensibilidad Microbiana

RESUMEN

This study analyzed arbuscular mycorrhizal fungi (AMF) activity and soil chemical properties in Aspidosperma pyrifolium, Bauhinia ungulata, Caesalpinia pyramidalis, and Caesalpinia ferrea. AMF spores, root colonization, total glomalin-related soil protein (T-GRSP), easily extracted GRSP (EE-GRSP), and soil chemical properties were measured four times (July 2019, 2020 and December 2019, 2020). Significant differences were observed in AMF spores, root colonization, T-GRSP, and EE-GRSP among the plant species and across seasons. For soil chemical properties, we observed differences among plant species. During the dry season, B. ungulata and C. pyramidalis had the highest AMF spores and root colonization (57.3 ± 0.27 spores 50 g soil-1 and 48.8 ± 1.05, respectively), whereas during the rainy season, C. pyramidalis and C. ferrea showed the highest AMF spores and root colonization (36.6 ± 0.13 spores 50 g soil-1 and 62.2 ± 1.17, respectively). A. pyrifolium showed the highest T-GRSP in both seasons. On the basis of the soil chemical properties, we found that (i) A. pyrifolium, B. ungulata, and C. ferrea showed the highest soil organic carbon (1.32 ± 0.03 g kg-1), phosphorus (7.01 ± 0.26 mg kg-1), and soil pH (5.85 ± 0.23) and (ii) C. pyramidalis showed the highest Ca2+, Mg2+, Na+, H+ + Al3+, K+, and soil total nitrogen (1.36 ± 0.04, 0.73 ± 0.01, 3.72 ± 0.85, 4.56 ± 0.12 cmolc kg-1, 15.43 ± 1.53 mg kg-1, and 0.16 ± 0.01 g kg-1, respectively). Our results highlight the advantage of AMF spores as perennating structures over other AM fungal propagules in seasonal vegetation like Caatinga.

Asunto(s)

Micorrizas , Raíces de Plantas , Rizosfera , Estaciones del Año , Microbiología del Suelo , Suelo , Esporas Fúngicas , Micorrizas/fisiología , Raíces de Plantas/microbiología , Suelo/química , Esporas Fúngicas/crecimiento & desarrollo , Esporas Fúngicas/aislamiento & purificación , Árboles/microbiología , Proteínas Fúngicas , Glicoproteínas

RESUMEN

Metarhizium rileyi has a broad biocontrol spectrum but is highly sensitive to abiotic factors. A Colombian isolate M. rileyi Nm017 has shown notorious potential against Helicoverpa zea. However, it has a loss of up to 22 % of its conidial germination after drying, which limits its potential as a biocontrol agent and further commercialization. Conidial desiccation resistance can be enhanced by nutritional supplements, which promotes field adaptability and facilitates technological development as a biopesticide. In this study, the effect of culture medium supplemented with linoleic acid on desiccation tolerance in Nm017 conidia was evaluated. Results showed that using a 2 % linoleic acid-supplemented medium increased the relative germination after drying by 41 % compared to the control treatment, without affecting insecticidal activity on H. zea. Also, the fungus increased the synthesis of trehalose, glucose, and erythritol during drying, independently of linoleic acid use. Ultrastructural analyses of the cell wall-membrane showed a loss of thickness by 22 % and 25 %, in samples obtained from 2 % linoleic acid supplementation and the control, respectively. Regarding its morphological characteristics, conidia inner area from both treatments did not change after drying. However, conidia from the control had a 24 % decrease in length/width ratio, whereas there was no alteration in conidia from acid linoleic. The average value of dry conidia elasticity coefficient from linoleic acid treatment was 200 % above the control. Medium supplementation with linoleic acid is a promising fermentation strategy for obtaining more tolerant conidia without affecting production and biocontrol parameters, compatible solutes synthesis, or modifying its cell configuration.

Asunto(s)

Medios de Cultivo , Ácido Linoleico , Metarhizium , Esporas Fúngicas , Metarhizium/fisiología , Metarhizium/efectos de los fármacos , Metarhizium/crecimiento & desarrollo , Ácido Linoleico/metabolismo , Ácido Linoleico/farmacología , Esporas Fúngicas/efectos de los fármacos , Esporas Fúngicas/crecimiento & desarrollo , Medios de Cultivo/química , Animales , Desecación , Control Biológico de Vectores , Colombia , Mariposas Nocturnas/microbiología

RESUMEN

Organic production systems are increasingly gaining market share; however, there are still few studies on their influence on the activity of soil microorganisms in sugarcane. Arbuscular mycorrhizal fungi are extremely sensitive to environmental changes, and their activity can be used as a parameter of comparison and quality between organic and conventional systems. The objective of this work was to evaluate mycorrhizal activity in different varieties of sugarcane under two production systems. This work was carried out in a commercial plantation of the Jalles Machado plant in the municipality of Goianésia in Goiás, Brazil. The values of spore density in the soil, mycorrhizal colonization rate in the roots and easily extractable glomalin were evaluated, and the associated fungal species were identified. There was no effect of sugarcane variety on the number of spores or the glomalin content in the soil. The conventional system presented significantly lower mycorrhizal colonization rates than did the organic system. The varieties cultivated under the conventional planting system showed a greater diversity of arbuscular mycorrhizal fungi, where 12 of the 13 different species of mycorrhizal fungi found in both cultivation systems occurred.

Asunto(s)

Micorrizas , Saccharum , Microbiología del Suelo , Saccharum/microbiología , Micorrizas/fisiología , Brasil , Raíces de Plantas/microbiología , Agricultura Orgánica , Suelo/química , Glicoproteínas , Esporas Fúngicas , Proteínas Fúngicas

RESUMEN

The antifungal activity of Serratia plymuthica CCGG2742, a bacterial strain isolated from grapes berries skin, against a phytopathogenic fungus isolated from blueberries was evaluated in vitro and in vivo. In order to characterize the wild fungal isolate, phylogenetic analysis using concatenated DNA sequences from the RPB2 and TEF1 genes and of the ITS region was performed, allowing the identification of the fungal isolate that was called Alternaria tenuissima CC17. Hyphae morphology, mycelium ultrastructure, conidia and reproductive structures were in agreement with the phylogenetic analysis. The antifungal activity of the S. plymuthica strain was dependent on the composition of the culture medium. The greatest inhibition of mycelial growth of A. tenuissima CC17 by S. plymuthica CCGG2742 was observed on YTS medium, which lacks of an easily assimilable carbon source. Fungal growth medium supplemented with 50 % of bacterial supernatant decreased the conidia germination of A. tenuissima CC17 up to 32 %. Preventive applications of S. plymuthica CCGG2742 to blueberries and tomato leaves at conidia:bacteria ratio of 1:100, protected in 77.8 ± 4.6 % and 98.2 ± 0.6 % to blueberries and tomato leaves from infection caused by A. tenuissima CC17, respectively. To the best of our knowledge, this is the first report on the antifungal activity of S. plymuthica against A. tenuissima, which could be used as a biological control agent of plant diseases caused by this fungal species. In addition, the results of this work could be a starting point to attribute the real importance of A. tenuissima as a pathogen of blueberries in Chile, which until now had been considered almost exclusively to A. alternata. Likewise, this research could be relevant to start developing highly effective strategies based on S. plymuthica CCGG2742 for the control of this important phytopathogenic fungus.

Asunto(s)

Alternaria , Antibiosis , Filogenia , Enfermedades de las Plantas , Serratia , Esporas Fúngicas , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/prevención & control , Alternaria/crecimiento & desarrollo , Alternaria/genética , Serratia/genética , Serratia/fisiología , Esporas Fúngicas/crecimiento & desarrollo , Micelio/crecimiento & desarrollo , Antifúngicos/farmacología , Solanum lycopersicum/microbiología , Hifa/crecimiento & desarrollo , Medios de Cultivo/química , Hojas de la Planta/microbiología , Vitis/microbiología

RESUMEN

Fusarium verticillioides causes significant decrease in corn yield and quality, and produces fumonisins, which represent a serious risk to human and animal health. Bacillus species can be an effective and environmentally friendly alternative for F. verticillioides biological control. In this study, some properties of cell-free supernatants (CFSs) of two Bacillus spp. identified as Bacillus subtilis (NT1, NT2) as well as the antifungal effect against F. verticillioides 97L were evaluated. B. subtilis NT1 and NT2 were isolated from commercially available fermented whole soybeans (Natto). Antifungal activity was observed in both CFSs of B. subtilis isolates (50-59 mm) obtained by co-culture suggesting that antifungal compound production depends on interaction between bacteria and fungi. Cell-free supernatants from the two B. subtilis isolates inhibited mycelial growth (77%-94%) and conidial germination (22%-74%) of F. verticillioides 97L. In addition, CFSs caused significant morphological changes such as distorted and collapsed hyphae with wrinkled surfaces and the presence of a large amount of extracellular material compared to the control without CFSs. Both B. subtilis isolates (NT1 and NT2) produced extracellular proteases, biosurfactants and polar low molecular weight compounds that probably act synergistically and may contribute to the antifungal activity. Antifungal compounds showed heat and pH stability and resistance to proteolytic enzymes. Furthermore, antifungal compounds showed high polarity, high affinity to water and a molecular weight less than 10 kDa. These results indicated that the two B. subtilis (NT1 and NT2) have potential as biocontrol agents for F. verticillioides.

Asunto(s)

Antifúngicos , Bacillus subtilis , Fusarium , Bacillus subtilis/metabolismo , Fusarium/efectos de los fármacos , Fusarium/crecimiento & desarrollo , Fusarium/metabolismo , Antifúngicos/farmacología , Antifúngicos/metabolismo , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/prevención & control , Glycine max/microbiología , Zea mays/microbiología , Esporas Fúngicas/crecimiento & desarrollo , Esporas Fúngicas/efectos de los fármacos , Antibiosis

RESUMEN

Pleurotus ostreatus is one of the most widely cultivated species in the world. It can be produced in many lignocellulosic substrates after carrying out a treatment to eliminate competing microorganisms. The most commonly used is pasteurization by steam or by immersion in hot water. The aim of this work is to evaluate if ozone can be employed as treatment for decontamination of the substrate used for the production of the edible mushroom P. ostreatus to control of green mold Trichoderma. Wheat straw was employed as a substrate. We used two different methodologies: bubbling ozone into a tank with water and the substrate, and injecting ozone into a closed tank with the substrate inside. Ten treatments were carried out including two treatments with inoculation by a spray of conidia of Trichoderma. The effect of ozone on the conidia was also evaluated. We found that the treatment of the substrate with ozone in immersed water resulted more effective (lower growth of Trichoderma) than injecting ozone into a closed tank. Anyway, we found that the contaminant fungi could grow on the substrate in both treatments with ozone. We observed that although ozone affected the conidia when it was bubbled into water, some of them still managed to survive and could germinate 72 h later. P. ostreatus could grow and produce fruiting bodies on a substrate that was previously treated with ozone and yields were not affected. Based on the results obtained, we conclude that ozone may not be an effective agent to control Trichoderma in highly contaminated substrates, at least in the experimental conditions that we used, for the production of P. ostreatus.

Asunto(s)

Ozono , Pleurotus , Trichoderma , Triticum , Pleurotus/crecimiento & desarrollo , Pleurotus/metabolismo , Ozono/farmacología , Trichoderma/metabolismo , Trichoderma/crecimiento & desarrollo , Triticum/microbiología , Esporas Fúngicas/efectos de los fármacos , Esporas Fúngicas/crecimiento & desarrollo

RESUMEN

This study aimed to evaluate the antifungal effect of SC319 sorghum phenolic extract (SPE) on the Aspergillus, Fusarium, Penicillium, Stenocarpella, Colletotrichum, and Macrophomina genera. SPE was extracted by 20% ethanol and used in four assays: (1) against Fusarium verticillioides in solid (PDA) and liquid (PD) potato dextrose media; (2) Minimum Inhibitory Concentration (MIC) assay with 16 fungi isolates; (3) Conidial Germination Rate (CGR) with 14 fungi isolates and (4) Growth Curve (GC) with 11 fungi isolates. There was no reduction in the mycelial growth (colony diameter and dry weight) and in the number of Fusarium verticillioides spores in assay 1 (PDA and PD). The colony's dry weight was almost six times higher in the presence than in the absence of SPE. All SPE samples presented MIC (assay 1) above the maximum concentration tested (5000 µg.mL-1) for the 16 isolates. Also, there was no inhibitory effect of SPE on conidia germination rate (CGR). Oppositely, in GC assay, the control had a higher CFU count than the samples with SPE in 24 h. This result suggests that SPE can delay the fungal growth in the first hours of incubation, which is an important finding that may help reduce the severity of fungal diseases in plants. However, further studies are needed to confirm these results, including sorghum genotypes with different profiles of phenolic compounds. Although the SC319 SPE was not effective as an antifungal agent, it may have potential as a growth promoter of beneficial fungi in the food and pharmaceutical industries.

Asunto(s)

Antifúngicos , Hongos , Pruebas de Sensibilidad Microbiana , Fenoles , Extractos Vegetales , Sorghum , Sorghum/microbiología , Antifúngicos/farmacología , Fenoles/farmacología , Extractos Vegetales/farmacología , Extractos Vegetales/química , Hongos/efectos de los fármacos , Hongos/crecimiento & desarrollo , Esporas Fúngicas/efectos de los fármacos , Esporas Fúngicas/crecimiento & desarrollo

RESUMEN

We investigated the impact of various complex organic nitrogen sources on the submerged liquid fermentation of Beauveria bassiana, a versatile entomopathogenic fungus known for producing hydrophilic yeast-like single cells called blastospores. Specifically, we examined yeast extract, autolyzed yeast, inactive yeast, cottonseed flour, corn bran, and corn gluten meal as nitrogen compounds with different carbon-to-nitrogen (C:N) ratios. Our comprehensive analysis encompassed blastospore production, tolerance to abiotic stresses, shelf stability after drying, and virulence against mealworm larvae, crucial attributes for developing effective blastospore-based biopesticides. Notably, cottonseed flour emerged as the optimal nitrogen source, yielding up to 2.5 × 109 blastospores/mL within 3 days in a bioreactor. These blastospores exhibited the highest tolerance to heat stress and UV-B radiation exposure. The endogenous C:N ratio in blastospore composition was also impacted by nitrogen sources. Bioassays with mealworm larvae demonstrated that blastospores from cottonseed flour were the most virulent, achieving faster lethality (lower LT50) and requiring a lower inoculum (LC50). Importantly, blastospores produced with cottonseed flour displayed extended viability during storage, surpassing the retention of viability compared to those from autolyzed yeast over 180 days at 4°C. Despite differences in storage viability, both nitrogen sources conferred similar long-term blastospore bioactivity against mealworms. In summary, this research advances our understanding of the crucial impact of complex organic nitrogen selection on the phenotypic traits of blastospores in association with their intracellular C:N ratio, contributing to the production of ecologically fit, shelf-stable, and virulent propagules for effective pest biocontrol programs. IMPORTANCE: Biological control through entomopathogenic fungi provides essential ecological services in the integrated management of agricultural pests. In the context of submerged liquid fermentation, the nutritional composition significantly influences the ecological fitness, virulence and quality of these fungi. This study specifically explores the impact of various complex organic nitrogen sources derived from agro-industrial byproducts on the submerged liquid fermentation of Beauveria bassiana, a versatile entomopathogenic fungus known for producing hydrophilic yeast-like blastospores. Notably, manipulating the nitrogen source during submerged cultivation can influence the quality, fitness, and performance of blastospores. This research identifies cottonseed flour as the optimal low-cost nitrogen source, contributing to increased production yields, enhanced multi-stress tolerance, heightened virulence with extended shelf life and long-term bioactivity. These findings deepen our understanding of the critical role of nitrogen compound selection in liquid media formulation, facilitating the production of ecologically fit and virulent blastospores for more effective pest biocontrol programs.

Asunto(s)

Beauveria , Nitrógeno , Esporas Fúngicas , Beauveria/metabolismo , Beauveria/fisiología , Beauveria/patogenicidad , Beauveria/crecimiento & desarrollo , Nitrógeno/metabolismo , Virulencia , Esporas Fúngicas/crecimiento & desarrollo , Animales , Estrés Fisiológico , Larva/microbiología , Fermentación , Agricultura , Residuos Industriales

RESUMEN

Argentina is among the most important lemon fruit producers in the world. Penicillium digitatum is the primary lemon fungal phytopathogen, causing green mold during the postharvest. Several alternatives to the use of synthetic fungicides have been developed, being the use of biocontrol yeasts one of the most promising. Although many of the reports are based on the use of a single yeast species, it has been shown that the combination of agents with different mechanisms of action can increase control efficiency through synergistic effects. The combined use of native yeasts with different mechanisms of action had not been studied as a biological control strategy in lemons. In this work, the mechanisms of action of native yeasts (Clavispora lusitaniae AgL21, Clavispora lusitaniae AgL2 and Clavispora lusitaniae AcL2) with biocontrol activity against P. digitatum were evaluated. Isolate AgL21 was selected for its ability to form biofilm, colonize lemon wounds, and inhibit fungal spore germination. The compatibility of C. lusitaniae AgL21 with two killer yeasts of the species Kazachstania exigua (AcL4 and AcL8) was evaluated. In vivo assays were then carried out with the yeasts applied individually or mixed in equal cell concentrations. AgL21 alone was able to control green mold with 87.5% efficiency, while individual killer yeasts were significantly less efficient (43.3% and 38.3%, respectively). Inhibitory effects were increased when C. lusitaniae AgL21 and K. exigua strains were jointly applied. The most efficient treatment was the combination of AgL21 and AcL4, reaching 100% efficiency in wound protection. The combination of AgL21 with AcL8 was as well promising, with an efficiency of 97.5%. The combined application of native yeasts showed a synergistic effect considering that the multiple mechanisms of action involved could hinder the development of green mold in lemon more efficiently than using single yeasts. Therefore, this work demonstrates that the integration of native yeasts with diverse modes of action can provide new insights to formulate effective microbial consortia. This could lead to the development of tailor-made biofungicides, allowing control of postharvest fungal diseases in lemons while remaining competitive with traditionally used synthetic chemicals.

Asunto(s)

Citrus , Fungicidas Industriales , Penicillium , Saccharomycetales , Levaduras , Citrus/microbiología , Fungicidas Industriales/farmacología , Esporas Fúngicas , Frutas/microbiología , Enfermedades de las Plantas/microbiología

RESUMEN

OBJETIVO: To identify and registry the most important aeroallergens trapped at the aerobiology station in the city of Samborondon, Ecuador. METHODS: Pollen grains and fungal spore counts were performed according to the standardized technique with a Hirst-type collection equipment, Burkard spore trap for seven days, following the recommendations of the National Allergy Bureau (NAB) of the American Academy of Allergy Asthma and Immunology (AAAAI). The equipment was installed on the roof of the Universidad de Especialidades Espiritu Santo (UEES), 25 m above ground level, coordinates: 2°07 ́57 ́ ́S 79°52 ́06 ́ ́W, in the city of Samborondon. The sampling period was performed from November 2022 to April 2023. RESULTS: We identified the following pollen families: Poaceae (258 grains/m3), Apocynaceae (Plumeria rubra pc) (214 grains/m3), Lamiaceae (180 grains/m3), Asteraceae Ambrosía spp.- (60 grains/m3), Chenopodiacea (27 grains/m3), Myrtaceae (17 grains/m3), Pinaceae (11 grains/m3), Betulaceae (7 grains/m3). Also identified fungical spores: Fuzariella spp./Leptosphaeria spp. (1899/m3), Cladosporium spp. (1407/m3), Nigrospora spp. (1183/m3), Dreschlera/Helmintosporum spp. (329/m3), Alternaria spp. (98/m3), Pithomyces spp. (79/m3), Curvularia spp. (48/m3), Stemphylium spp. (46/m3). CONCLUSIONS: We reported the first study of aerobiology (capture and identification of environmental pollens and fungi) in the city of Samborondon. The inhabitants of this area are exposed to different aeroallergens with a predominance of Poaceaes pollen and Fuzzariella spp./Leptosphaeria spp. spores. The identified allergens should be part of the usual allergy studies. The results of this first preliminary study should be compared with information from the forthcoming years, which will help to identify variations in the concentration of seasonal aeroallergens, annual fluctuations, and extend the traps to other parts of the city.

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OBJETIVO: Identificar y registrar los aeroalérgenos más importantes captados en la estación de aerobiología en la ciudad de Samborondón, Ecuador. MÉTODOS: Los conteos de granos de polen y esporas de hongos se realizaron según la técnica estandarizada, con un equipo colector tipo Hirst, Burkard spore trap for seven days, siguiendo las recomendaciones de la National Allergy Bureau (NAB) de la American Academy Allergy Asthma and Immunology (AAAAI). El equipo se instaló en la azotea de la Universidad Espíritu Santo (UEES), en la ciudad de Samborondón, a 25 m de altura desde el nivel del suelo, 2°07´57´´S 79°52´06´´O. El periodo de captación se llevó a cabo entre noviembre de 2022 y abril de 2023. RESULTADOS: Identificamos las siguientes familias polínicas: Poaceae (258 granos/m3), Apocynaceae (Plumeria rubra pc) (214 granos/m3), Lamiaceae (180 granos/m3), Asteraceae Ambrosía spp.- (60 granos/m3), Chenopodiacea (27 granos/m3), Myrtaceae (17 granos/m3), Pinaceae (11 granos/m3), Betulaceae (7 granos/m3). Además esporas fúngicas: Fuzariella spp./Leptosphaeria spp. (1899/m3), Cladosporium spp. (1407/m3), Nigrospora spp. (1183/m3), Dreschlera/Helmintosporum spp. (329/m3), Alternaria spp. (98/m3), Pithomyces spp. (79/m3), Curvularia spp. (48/m3), Stemphylium spp. (46/m3). CONCLUSIONES: Se reporta el primer estudio de aerobiología (captación e identificación de pólenes y hongos ambientales), en la ciudad de Samborondón. Los habitantes de esta zona están expuestos a diferentes aeroalérgenos con predominancia al polen de Poaceaes y esporas de Fuzzariella spp./Leptosphaeria spp. Los alérgenos identificados deberían formar parte de los estudios alergológicos habituales. Los resultados de este primer estudio preliminar deberían ser comparados con información de los siguientes años para ayudar a identificar las variaciones de concentración de aeroalérgenos estacionales, las fluctuaciones anuales, y extender los captadores a otros puntos de la ciudad.

Asunto(s)

Alérgenos , Polen , Esporas Fúngicas , Ecuador , Polen/inmunología , Monitoreo del Ambiente