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1.
Rev Argent Microbiol ; 56(2): 187-190, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38519396

RESUMEN

In August 2018, symptoms of apical and basal rot resembling those caused by Sclerotinia sclerotiorum infection were observed in a commercial Brussels sprouts field in North Patagonia, Argentina. The incidence of apical and basal rot was 23.30% and 2.30%, respectively. Carpogenic germination of sclerotia was detected in shaded, highly humid soil areas. To our knowledge, this is the first report of carpogenic germination of sclerotia from S. sclerotiorum in North Patagonia.


Asunto(s)
Ascomicetos , Brassica , Enfermedades de las Plantas , Argentina , Ascomicetos/fisiología , Enfermedades de las Plantas/microbiología , Brassica/microbiología
2.
Phytopathology ; 114(3): 590-602, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38079394

RESUMEN

Growers often use alternations or mixtures of fungicides to slow down the development of resistance to fungicides. However, within a landscape, some growers will implement such resistance management methods, whereas others do not, and may even apply solo components of the resistance management program. We investigated whether growers using solo components of resistant management programs affect the durability of disease control in fields of those who implement fungicide resistance management. We developed a spatially implicit semidiscrete epidemiological model for the development of fungicide resistance. The model simulates the development of epidemics of spot-form net blotch disease, caused by the pathogen Pyrenophora teres f. maculata. The landscape comprises three types of fields, grouped according to their treatment program, with spore dispersal between fields early in the cropping season. In one field type, a fungicide resistance management method is implemented, whereas in the two others, it is not, with one of these field types using a component of the fungicide resistance management program. The output of the model suggests that the use of component fungicides does affect the durability of disease control for growers using resistance management programs. The magnitude of the effect depends on the characteristics of the pathosystem, the degree of inoculum mixing between fields, and the resistance management program being used. Additionally, although increasing the amount of the solo component in the landscape generally decreases the lifespan within which the resistance management program provides effective control, situations exist where the lifespan may be minimized at intermediate levels of the solo component fungicide. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.


Asunto(s)
Ascomicetos , Fungicidas Industriales , Hordeum , Fungicidas Industriales/farmacología , Australia Occidental , Enfermedades de las Plantas/prevención & control
3.
MycoKeys ; 99: 25-43, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37588798

RESUMEN

Two new multispored species from China, Lecanoraanhuiensis Li J. Li & Printzen, sp. nov. and Lecanorapseudojaponica Li J. Li & Printzen, sp. nov. are described and illustrated here, based on morphological, chemical and molecular evidence. Lecanoraanhuiensis is characterised by an epruinose, yellowish-brown to deep brown apothecial disc, an epihymenium with fine crystals, an amphithecium with small crystals, 16-spored asci and the presence of zeorin, in addition to atranorin. Lecanorapseudojaponica is characterised by an epruinose, red-brown apothecial disc, an epihymenium without crystals, an amphithecium with small crystals, 8 or 16- spored asci and the presence of zeorin and the stictic acid complex, in addition to atranorin. Phylogenetic reconstructions, based on mtSSU, nrITS and nrLSU suggest that these two species are members of the Lecanorasubfusca group. They are compared with morphologically similar and phylogenetically related species, based on a nrITS dataset. Phylogenetic results show that the multispored taxa of Lecanora are polyphyletic. The number of ascospores per ascus appears to be a taxonomic character of minor importance. Detailed descriptions, discussions and figures for the two new species from China and a key for the multispored species of Lecanora worldwide are provided.

4.
Plant Dis ; 107(12): 3754-3762, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37368443

RESUMEN

White mold caused by the fungal pathogen Sclerotinia sclerotiorum (Lib.) de Bary is one of the most important biological constraints to dry bean (Phaseolus vulgaris L.) production in Canada. Disease forecasting is one tool that could help growers manage the disease while reducing fungicide use. However, predicting white mold epidemics has remained difficult due to their sporadic occurrence. In this study, over the course of four growing seasons (2018 to 2021), we surveyed dry bean fields in Alberta and collected daily in-field weather data and daily in-field ascospore counts. White mold levels were variable and generally high in all years, confirming that the disease is ubiquitous and a constant threat to dry bean production. Ascospores were present throughout the growing season, and mean ascospore levels varied by field, month, and year. Models based on in-field weather and ascospore levels were not highly predictive of final disease incidence in a field, suggesting that environment and pathogen presence were not limiting factors to disease development. Rather, significant effects of market class on disease were found, with pinto beans, on average, having the highest disease incidence (33%) followed by great northern (15%), black (10%), red (6%), and yellow (5%). When incidence of these market classes was modeled separately, different environmental variables were important in each model; however, average wind speed was a significant variable in all models. Taken together, these findings suggest that white mold management in dry bean should focus on fungicide use, plant genetics, irrigation management, and other agronomic factors.


Asunto(s)
Ascomicetos , Fungicidas Industriales , Phaseolus , Alberta , Fungicidas Industriales/farmacología , Ascomicetos/genética , Phaseolus/microbiología , Esporas Fúngicas
5.
Plant Dis ; 107(11): 3448-3456, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37081630

RESUMEN

Although fungal canker diseases constitute a limiting factor to orchard productivity and longevity, little is known about the effects of temperature on spore germination and mycelial growth of the fungal causal agents. Accordingly, the germination of spores and colony growth of Calosphaeria pulchella, Cytospora sorbicola, and Eutypa lata were evaluated after incubation on 2% water agar and 4% potato dextrose agar, respectively, at 5, 10, 15, 20, 25, 30, 35, and 40°C. Temperature optima for spore germination and mycelial growth were derived from nonlinear models fitted to germination rates and colony diameter data. The optimal temperatures for spore germination of Cal. pulchella were 28.5°C for ascospores and 29.2°C for conidia. The optimal temperatures for Cyt. sorbicola conidia and E. lata ascospore germination were 25.8 and 23.1°C, respectively. The germination of ascospores and conidia of Cal. pulchella at temperatures below 15°C required an incubation time of at least 72 h. Ascospores of E. lata and conidia of Cyt. sorbicola germinated at 10°C after 36 h. The optimal temperature for colony growth of Cal. pulchella was 24.6°C, whereas it was 21.7°C for both Cyt. sorbicola and E. lata. Our study indicates that temperature requirements for basic biological functions are higher for Cal. pulchella than for Cyt. sorbicola and E. lata. The overall higher temperatures of California relative to other cherry-producing regions in the United States or worldwide could explain the prevalence of Calosphaeria canker in the state. Conversely, Cyt. sorbicola and E. lata appear better adapted to cooler temperatures.


Asunto(s)
Prunus avium , Temperatura , Agar/farmacología , Germinación , Esporas Fúngicas
6.
Curr Res Food Sci ; 5: 1524-1529, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36132492

RESUMEN

The use of light-emitting diode (LED) technology for the non-thermal processing of foods is a major topic of interest among various research groups. This study is aimed at inactivating the Eupenicillium javanicum ascospores present in strawberry and apple juices using a combination of a visible LED (vis-LED, 430-630 nm, 216-420 J/cm2) and 90 °C thermal treatment, as well as to compare the findings with the inactivation done using thermal-processes alone. The results showed that violet-blue LEDs within the range of 430 and 460 nm with an energy between 300 and 420 J/cm2 were better for the inactivation of E. javanicum ascospores than the green and red LEDs which were within the 550-630 nm region with an energy range from 216 to 264 J/cm2. Furthermore, the inactivation process conducted using vis-LED was affected by the juice's soluble solid contents and the calculated D LED-values were within the range of 116.3 J/cm2 to 277.8 J/cm2 in juices with a Brix scale value of 10-20°. Finally, the inactivation rate obtained from combining a violet-blue LED with a 90 °C thermal treatment was similar to the rate of using the thermal treatment alone.

7.
Genetics ; 219(2)2021 10 02.
Artículo en Inglés | MEDLINE | ID: mdl-34849873

RESUMEN

The formation of fruiting bodies is one of the most complex developmental processes in filamentous ascomycetes. It requires the development of sexual structures that give rise to meiosporangia (asci) and meiotic spores (ascospores) as well as surrounding structures for protection and dispersal of the spores. Previous studies have shown that these developmental processes are accompanied by significant changes of the transcriptome, and comparative transcriptomics of different fungi as well as the analysis of transcriptome changes in developmental mutants have aided in the identification of differentially regulated genes that are themselves involved in regulating fruiting body development. In previous analyses, we used transcriptomics to identify the genes asm2 and spt3, which result in developmental phenotypes when deleted in Sordaria macrospora. In this study, we identified another gene, asm3, required for fruiting body formation, and performed transcriptomics analyses of Δasm2, Δasm3, and Δspt3. Deletion of spt3, which encodes a subunit of the SAGA complex, results in a block at an early stage of development and drastic changes in the transcriptome. Deletion mutants of asm2 and asm3 are able to form fruiting bodies, but have defects in ascospore maturation. Transcriptomics analysis of fruiting bodies revealed a large overlap in differentially regulated genes in Δasm2 and Δasm3 compared to the wild type. Analysis of nuclear distribution during ascus development showed that both mutants undergo meiosis and postmeiotic divisions, suggesting that the transcriptomic and morphological changes might be related to defects in the morphogenesis of structural features of the developing asci and ascospores.


Asunto(s)
Cuerpos Fructíferos de los Hongos/genética , Proteínas Fúngicas/metabolismo , Regulación Fúngica de la Expresión Génica , Sordariales/genética , Cuerpos Fructíferos de los Hongos/crecimiento & desarrollo , Proteínas Fúngicas/genética , Regulación del Desarrollo de la Expresión Génica , Sordariales/crecimiento & desarrollo , Sordariales/metabolismo , Transcriptoma
8.
J Fungi (Basel) ; 7(10)2021 Oct 14.
Artículo en Inglés | MEDLINE | ID: mdl-34682281

RESUMEN

Aspergillus fumigatus is a ubiquitous saprophytic mold that can cause a range of clinical syndromes, from allergic reactions to invasive infections. Amphotericin B (AMB) is a polyene antifungal drug that has been used to treat a broad range of systemic mycoses since 1958, including as a primary treatment option against invasive aspergillosis in regions with high rates (≥10%) of environmental triazole resistance. However, cases of AMB-resistant A. fumigatus strains have been increasingly documented over the years, and high resistance rates were recently reported in Brazil and Canada. The objective of this study is to identify candidate mutations associated with AMB susceptibility using a genome-wide association analysis of natural strains, and to further investigate a subset of the mutations in their putative associations with differences in AMB minimum inhibitory concentration (MIC) and in growths at different AMB concentrations through the analysis of progeny from a laboratory genetic cross. Together, our results identified a total of 34 candidate single-nucleotide polymorphisms (SNPs) associated with AMB MIC differences-comprising 18 intergenic variants, 14 missense variants, one synonymous variant, and one non-coding transcript variant. Importantly, progeny from the genetic cross allowed us to identify putative SNP-SNP interactions impacting progeny growth at different AMB concentrations.

9.
J Basic Microbiol ; 61(10): 923-939, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34374439

RESUMEN

Pea (Pisum sativum L.) is of global importance as a food crop for its edible pod and seed. A new disease causing the tan to light brown blighted stems and pods has occurred in pea (P. sativum L.) plants in Chapainawabganj district, Bangladesh. A fungus with white-appressed mycelia and large sclerotia was consistently isolated from symptomatic tissues. The fungus formed funnel-shaped apothecia with sac-like ascus and endogenously formed ascospores. Healthy pea plants inoculated with the fungus produced typical white mold symptoms. The internal transcribed spacer sequences of the fungus were 100% similar to Sclerotinia sclerotiorum, considering the fungus to be the causative agent of white mold disease in pea, which was the first record in Bangladesh. Mycelial growth and sclerotial development of S. sclerotiorum were favored at 20°C and pH 5.0. Glucose was the best carbon source to support hyphal growth and sclerotia formation. Bavistin and Amistar Top inhibited the radial growth of the fungus completely at the lowest concentration. In planta, foliar application of Amistar Top showed the considerable potential to control the disease at 1.0% concentration until 7 days after spraying, while Bavistin prevented infection significantly until 15 days after spraying. A large majority (70.93%) of genotypes, including tested released pea cultivars, were susceptible, while six genotypes (6.98%) appeared resistant to the disease. These results on identification, characterization, host resistance, and fungicidal control of white mold could be valuable to achieve improved management of a new disease problem for pea cultivation.


Asunto(s)
Ascomicetos/patogenicidad , Pisum sativum/microbiología , Enfermedades de las Plantas/microbiología , Ascomicetos/genética , Ascomicetos/crecimiento & desarrollo , Ascomicetos/aislamiento & purificación , Fungicidas Industriales/farmacología , Genotipo , Micelio/efectos de los fármacos , Micelio/crecimiento & desarrollo , Virulencia
10.
Front Cell Infect Microbiol ; 11: 785157, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-35145921

RESUMEN

With population genetic evidence of recombination ongoing in the natural Aspergillus fumigatus population and a sexual cycle demonstrated in the laboratory the question remained what the natural niche for A. fumigatus sex is. Composting plant-waste material is a known substrate of A. fumigatus to thrive and withstand temperatures even up to 70°C. Previous studies have shown indirect evidence for sexual reproduction in these heaps but never directly demonstrated the sexual structures due to technical limitations. Here, we show that flower bulb waste material from stockpiles undergoing composting can provide the conditions for sexual reproduction. Direct detection of ascospore structures was shown in agricultural flower bulb waste material by using a grid-based detection assay. Furthermore, we demonstrate that ascospores can germinate after exposure to 70°C for up to several days in contrast to asexual conidia that are unable to survive a two-hour heat shock. This indicates a sufficient time frame for ascospores to survive and escape composting stockpiles. Finally, sexual crosses with cleistothecium and viable ascospore formation could successfully be performed on flower bulb waste material. Recombination of A. fumigatus can now be explained by active sexual reproduction in nature as we show in this study that flower bulb waste material provides an environmental niche for sex.


Asunto(s)
Aspergillus fumigatus , Reproducción , Aspergillus fumigatus/genética , Flores , Raíces de Plantas , Esporas Fúngicas/genética
11.
Methods Mol Biol ; 2234: 79-85, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33165781

RESUMEN

This chapter describes how mating assays in Trichoderma reesei can successfully be performed and which specific prerequisites of industrial strains originating from strain QM6a have to be met for successful mating experiments.


Asunto(s)
Cruzamientos Genéticos , Hypocreales/genética , Bioensayo , Genes del Tipo Sexual de los Hongos , Esporas Fúngicas/fisiología
12.
Plant Dis ; 105(7): 1912-1918, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-33320040

RESUMEN

Stemphylium leaf blight (SLB), caused by Stemphylium vesicarium, is an important foliar disease of onion in northeastern North America. The pathogen produces conidia and ascospores, but the relative contributions of these spore types to epidemics in onion is not known. Determining the abundance of ascospores and conidia during the growing season could contribute to a disease forecasting model. Airborne ascospores and conidia of S. vesicarium were trapped during the growing season of 2015 and 2016 at an onion trial in southern Ontario, Canada, using a Burkard 7-day volumetric sampler. Meteorological data were recorded hourly. Ascospore numbers peaked before the crop was planted and declined rapidly with time and at daily mean air temperatures >15°C. Conidia were present throughout the growing season and appear to be closely related to the development of SLB on onion. Daily spore concentrations were variable, but 59 to 73% of ascospores and approximately 60% of conidia were captured between 0600 and 1200 h. Spore concentrations increased 24 to 72 h after rainfall and precipitation and leaf wetness duration were consistently and positively associated with increases in numbers of conidia and subsequent SLB incidence. The first symptoms of SLB coincided with high numbers of conidia, rainfall, leaf wetness duration ≥8 h, and days with average daily temperature ≥18°C. The number of airborne ascospores was very low by the time SLB symptoms were observed. Ascospores may initiate infection on alternative hosts in early spring, while conidia are the most important inoculum for the epidemic on onions.


Asunto(s)
Cebollas , Enfermedades de las Plantas , Ascomicetos , Ontario , Esporas Fúngicas , Tiempo (Meteorología)
13.
Front Microbiol ; 11: 1595, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32849332

RESUMEN

Fusarium graminearum is a phytopathogenic fungus that causes Fusarium head blight in small-grain cereals, such as wheat, with significant yield reductions. Moreover, it contaminates the cereal grains with health-threatening mycotoxins, such as deoxynivalenol (DON), jeopardizing food and feed safety. Plant-based biopesticides, i.e. botanicals, have recently gained increased interest in crop protection as alternatives to synthetic chemical products. The main objective of this study was to test the control efficacy of botanicals based on white or Indian/Oriental mustard seed flours (Tillecur - Ti, Pure Yellow Mustard - PYM, Pure Oriental Mustard - POM, Oriental Mustard Bran - OMB) on F. graminearum infection and mycotoxin accumulation in wheat grain. Botanicals at 2% concentration showed a higher efficacy in inhibiting mycelium growth in vitro compared with a prothioconazole fungicide (F). In the growth chamber experiment under controlled conditions, the spraying agents reduced DON content in grain in the following order: F = Ti = PYM > POM > OMB. The antifungal activity of the botanicals may be attributed to their bioactive matrices containing isothiocyanates (ITCs) and phenolic acids. Allyl ITC was detected in POM and OMB at 8.38 and 4.48 mg g-1, while p-hydroxybenzyl ITC was found in Ti and PYM at 2.56 and 2.44 mg g-1, respectively. Considerable amounts of various phenolic acids were detected in all botanicals. Under field conditions, only the use of F significantly decreased F. graminearum infection and DON content in grain. An additional important finding of this study is that disease control was more difficult when infection was done with ascospores than conidia, which might have several potential implications considering that ascospores are more important in Fusarium head blight epidemics. Our results suggest that mustard-based botanicals are promising biopesticides for the control of Fusarium head blight in small-grain cereals, but for field applications, an appropriate formulation is necessary to stabilize and prolong the antifungal activity, especially against ascospores.

14.
Food Microbiol ; 88: 103406, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-31997762

RESUMEN

This study aims to assess, by means of a full factorial design, the effect of storage temperature (10-30 °C), water activity (aw, 0.87-0.89), headspace oxygen (O2) level (0.15-0.80%) and pasteurization intensity (95 °C-105 °C/15sec) on the time to visible growth (tv, days) of Aspergillus fischerianus on acidified Potato Dextrose Agar (aPDA, pH 3.6) for up to 90 days. Moreover, in order to validate the results obtained on aPDA, 12 conditions were selected and assessed in concentrate strawberry-puree based medium. Overall, storage temperature had the greatest effect on the tv of A. fischerianus on the evaluated conditions. At 10 °C, no visible growth was observed over the 90 day incubation period, whilst visible mycelia (diameter ≥ 2 mm) were present in 37% and 89% of the conditions at 22 °C and 30 °C, respectively. Pasteurization intensity had only a minor effect on the outgrowth of A. fischerianus. Growth inhibition was observed when aw was reduced to 0.870 ± 0.005 in combination with very low headspace O2 levels (0.15% ± 0.10) in both, aPDA and concentrate strawberry-based media, regardless of the incubation temperature and heat pasteurization intensity. Overall, longer tv's were required when incubation was done at 22 °C compared to 30 °C. Ultimately, the effect of O2 (0.05 and 1%) and pasteurization intensity (95 °C and 105 °C/15sec) were evaluated on totally 22 fruit purees (un-concentrates and concentrates) over a 60 day storage period. None of the concentrates purees (aw ≤0.860) evaluated in this study supported the growth of A. fischerianus. On the other hand, A. fischerianus growth inhibition was only observed when the O2 levels were ≤0.05% on un-concentrates fruit purees (aw ≥ 0.980) stored at ambient temperature (22 °C). Combination of multiple stress factors effectively inhibited growth of A. fischerianus. In general, storage of fruit purees at low temperatures (<10 °C) or distribution in the form of concentrates can be considered as important strategies to prevent the growth of spoilage associated heat-resistant moulds.


Asunto(s)
Aspergillus/crecimiento & desarrollo , Conservación de Alimentos/métodos , Calor , Oxígeno/metabolismo , Pasteurización , Agua , Aspergillus/metabolismo , Recuento de Colonia Microbiana , Manipulación de Alimentos/métodos , Microbiología de Alimentos/métodos , Almacenamiento de Alimentos/métodos , Fragaria/microbiología , Frutas/microbiología , Concentración de Iones de Hidrógeno , Neosartorya/crecimiento & desarrollo , Esporas Fúngicas/crecimiento & desarrollo
15.
Genes (Basel) ; 11(1)2020 01 16.
Artículo en Inglés | MEDLINE | ID: mdl-31963266

RESUMEN

The velvet regulator VosA plays a pivotal role in asexual sporulation in the model filamentous fungus Aspergillus nidulans. In the present study, we characterize the roles of VosA in sexual spores (ascospores) in A. nidulans. During ascospore maturation, the deletion of vosA causes a rapid decrease in spore viability. The absence of vosA also results in a lack of trehalose biogenesis and decreased tolerance of ascospores to thermal and oxidative stresses. RNA-seq-based genome-wide expression analysis demonstrated that the loss of vosA leads to elevated expression of sterigmatocystin (ST) biosynthetic genes and a slight increase in ST production in ascospores. Moreover, the deletion of vosA causes upregulation of additional gene clusters associated with the biosynthesis of other secondary metabolites, including asperthecin, microperfuranone, and monodictyphenone. On the other hand, the lack of vosA results in the downregulation of various genes involved in primary metabolism. In addition, vosA deletion alters mRNA levels of genes associated with the cell wall integrity and trehalose biosynthesis. Overall, these results demonstrate that the velvet regulator VosA plays a key role in the maturation and the cellular and metabolic integrity of sexual spores in A. nidulans.


Asunto(s)
Aspergillus nidulans/fisiología , Proteínas Fúngicas/metabolismo , Metabolismo Secundario/fisiología , Esporas Fúngicas/metabolismo , Reproducción Asexuada/fisiología , Esporas Fúngicas/genética , Esterigmatocistina/biosíntesis
16.
MycoKeys ; 60: 1-15, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31723334

RESUMEN

Triblidiaceae (Rhytismatales) currently consists of two genera: Triblidium and Huangshania. Triblidium is the type genus and is characterised by melanized apothecia that occur scattered or in small clusters on the substratum, cleistohymenial (opening in the mesohymenial phase), inamyloid thin-walled asci and hyaline muriform ascospores. Before this study, only the type species, Triblidium caliciiforme, had DNA sequences in the NCBI GenBank. In this study, six specimens of Triblidium were collected from China and France and new ITS, mtSSU, LSU and RPB2 sequences were generated. Our molecular phylogenetic analysis and morphological study demonstrated three new species of Triblidium, which are formally described here: T. hubeiense, T. rostriforme and T. yunnanense. Additionally, our results indicated that Huangshania that was considered to be distinct from Triblidium because of its elongated, transversely-septate ascospores, is congeneric with Triblidium. Therefore, we have placed Huangshania in synonymy under Triblidium, rendering Triblidiaceae a monotypic family.

17.
Curr Protoc Microbiol ; 54(1): e87, 2019 09.
Artículo en Inglés | MEDLINE | ID: mdl-31518066

RESUMEN

Aspergillus fumigatus is an opportunistic human fungal pathogen, capable of causing invasive aspergillosis in patients with compromised immune systems. The fungus was long considered a purely asexual organism. However, a sexual cycle was reported in 2009, with methods described to induce mating under laboratory conditions. The presence of a sexual cycle now offers a valuable tool for classical genetic analysis of the fungus, such as allowing determination of whether traits of interest are mono- or poly-genic in nature. For example, the sexual cycle is currently being exploited to determine the genetic basis of traits of medical importance such as resistance to azole antifungals and virulence, and to characterize the genes involved. The sexual cycle can also be used to assess the possibility of gene flow between isolates. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. This unit describes protocols for culturing of A. fumigatus and for inducing sexual reproduction between compatible MAT1-1 and MAT1-2 isolates of the species. The unit also provides working methods for harvesting sexual structures, isolating single-spore progeny and confirming whether sexual recombination has occurred. © The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.


Asunto(s)
Aspergillus fumigatus/crecimiento & desarrollo , Aspergillus fumigatus/fisiología , Micología/métodos , Reacción en Cadena de la Polimerasa/métodos , Preservación Biológica/métodos , Aspergilosis/microbiología , Aspergillus fumigatus/genética , Medios de Cultivo/química , Medios de Cultivo/metabolismo , Genes del Tipo Sexual de los Hongos , Humanos , Micología/instrumentación , Esporas Fúngicas/genética , Esporas Fúngicas/crecimiento & desarrollo , Esporas Fúngicas/fisiología
18.
Fungal Biol ; 123(10): 763-772, 2019 10.
Artículo en Inglés | MEDLINE | ID: mdl-31542193

RESUMEN

Septoria tritici blotch (STB) caused by the heterothallic ascomycete Zymoseptoria tritici is currently one of the most devastating diseases of wheat worldwide. The extent of sexual reproduction of this pathogen is well documented on bread wheat, but not on durum wheat. The objective of the present study was to quantify the occurrence of Z. tritici sexual reproduction on durum wheat in the Tunisian environment. The assessment was undertaken using a triple approach combining fruiting body assessment, ascospore trapping and population genetic analyses. The results highlighted the formation of pseudothecia on leaves and stubble from the autumn until the end of the growing season. Likewise, qPCR monitoring highlighted a constant release of Z. tritici airborne inoculum during the wheat-growing season, with a peak of production at the end of the season. Genetic investigations using microsatellites revealed high levels of gene and genotypic diversities, an equal distribution of mating types, and a lack of genetic clustering within and between growing seasons. Taken together, these findings indicate that Z. tritici undergoes sexual reproduction on durum wheat in Tunisia at least to the same extent than on bread wheat in Western Europe, and that the dry and warm climate does not affect the mating process of the fungus. Frequent occurrence of sexual reproduction is a valuable knowledge to take into account in STB control strategies on durum wheat.


Asunto(s)
Ascomicetos/fisiología , Cuerpos Fructíferos de los Hongos/crecimiento & desarrollo , Variación Genética , Enfermedades de las Plantas/microbiología , Triticum/microbiología , Ascomicetos/clasificación , Ascomicetos/genética , Ascomicetos/crecimiento & desarrollo , Clima , Cuerpos Fructíferos de los Hongos/genética , Genotipo , Repeticiones de Microsatélite , Reproducción , Esporas Fúngicas , Túnez
19.
Food Microbiol ; 81: 2-11, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-30910084

RESUMEN

This review highlights the variability of fungal spores with respect to cell type, mode of formation and stress resistance. The function of spores is to disperse fungi to new areas and to get them through difficult periods. This also makes them important vehicles for food contamination. Formation of spores is a complex process that is regulated by the cooperation of different transcription factors. The discussion of the biology of spore formation, with the genus Aspergillus as an example, points to possible novel ways to eradicate fungal spore production in food. Fungi can produce different types of spores, sexual and asexually, within the same colony. The absence or presence of sexual spore formation has led to a dual nomenclature for fungi. Molecular techniques have led to a revision of this nomenclature. A number of fungal species form sexual spores, which are exceptionally stress-resistant and survive pasteurization and other treatments. A meta-analysis is provided of numerous D-values of heat-resistant ascospores generated during the years. The relevance of fungal spores for food microbiology has been discussed.


Asunto(s)
Microbiología de Alimentos , Esporas Fúngicas/fisiología , Aspergillus/fisiología , Contaminación de Alimentos , Hongos/citología , Hongos/genética , Hongos/crecimiento & desarrollo , Hongos/fisiología , Calor , Pasteurización , Esporas Fúngicas/citología , Esporas Fúngicas/genética , Esporas Fúngicas/crecimiento & desarrollo , Termotolerancia , Factores de Transcripción
20.
Mycology ; 10(1): 49-60, 2019 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-30834152

RESUMEN

Medicinal plants are considered as sources of novel and unexplored groups of endophytic microorganisms. A study on endophytic fungal species from the medicinal plant Withania somnifera (L.) Dunal resulted in the isolation of a Penicillium isolate (WSR 62) with antibiotic activity. Phylogenetic analysis showed that the isolate belongs to section Lanata-divaricata, and it is most closely related to P. javanicum. Subsequent detailed phylogenetic analyses using partial ß-tubulin (BenA), calmodulin (CaM) and DNA-dependent RNA polymerase II (RPB2) gene sequences of a larger number of related strains revealed the distinctiveness of the isolate in the P. javanicum-clade. The isolate grows fast on Czapek yeast autolysate agar (CYA) and malt extract agar (MEA) incubated at 25°C, 30°C and 37°C. The obverse colony colour is dominated by the conspicuous production of cleistothecia and is greyish yellow on CYA and yellowish brown on MEA. Production of cleistothecia containing prominent spinose ascospores was present on all tested agar media. Based on the phylogenetic analysis and the phenotypic characterisation, strain WSR 62 from Withania is described here as a novel species named Penicillium setosum.

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