No description available.

No description available.

Plant pathogens are important agents which can influence the quality, yield and health status of agricultural production. The aim of diploma thesis was to evaluate pos-sibilities of the reduction of Fusarium species occurrence in maize. The data from field experiments in Pohořelice were evaluated in 2014. The fields were treated by ancillary soil preparation on microbiological base. The content of Fusarium mycotoxins de-oxynivalenol and zearalenon was determined in randomly selected maize plants. The maximum content of these mycotoxins is limited by commission regulation (EC) No 1881/2006. All analysed maize samples were determined over the limit for deoxyniva-lenol. Only one sample was under the limit for zearalenon. The yield of treated variants was not different in comparison with untreated ones. The results indicate there was no effect of treatment on Fusarium species development and mycotoxins content. These results are only preliminary, experiment should be replied in different years and locali-ties.

No description available.

Doctor of Philosophy / Department of Plant Pathology / Christopher R. Little / Fusarium spp. are among the most important pathogen groups on soybeans. However, information regarding this genus on soybean seeds in the state of Kansas remains underexplored. Therefore, the goal of this study was to characterize the identity, frequency, and pathogenicity of soybean seedborne Fusarium spp. in the state of Kansas. For the identification and frequency of seedborne Fusarium spp., culture-dependent (i.e. semi-selective medium) and -independent (i.e. DNA metabarcoding) approaches were used. Also, information regarding the pathogenicity of the most common seedborne Fusarium spp. from soybeans was assessed to better understand their role as soybean pathogens. Overall, eleven Fusarium spp. were identified in this study. Semi-selective media showed that approximately 33% of soybean seed samples were infected with Fusarium spp. Moreover, Fusarium spp. were isolated from seed sampled from 80% of the locations in Kansas. Furthermore, a low incidence of Fusarium spp. was observed within infected seed samples and averaged 2%. Nine Fusarium spp. were found in soybean seeds using the culture-dependent approach. Fusarium semitectum was the most frequent, followed by F. proliferatum and F. verticillioides. Fusarium acuminatum, F. equiseti, F. fujikuroi, F. graminearum, F. oxysporum, and F. thapsinum were found in lower frequencies among naturally infected seeds. DNA metabarcoding experiments showed that Fusarium spp. are more frequent in soybean seeds than previously known. All asymptomatic soybean seeds analyzed, using Illumina MiSeq platform, showed the presence of the genus Fusarium including two pathogenic species, F. proliferatum and F. thapsinum. Fusarium acuminatum, F. merismoides, F. solani, F. semitectum, and Fusarium sp. were also identified using the culture-independent approach. Preliminary results also showed that F. proliferatum and F. thapsinum were observed in all three major soybean seed tissues: seed coat, cotyledons, and the embryo axis. Depending on the soybean genotype, inoculum potential and aggressiveness, F. proliferatum, F. graminearum, F. fujikuroi, F. oxysporum, F. semitectum, F. thapsinum, and F. verticillioides were pathogenic to soybean and negatively affect soybean seed quality, at different levels, in controlled conditions. Moreover, F. equiseti and F. acuminatum did not cause significant damage to soybean seeds and seedlings. Understanding seedborne Fusarium spp. and their influence on soybean seed and seedling diseases is critical for the development of effective disease control strategies, especially regarding early detection of pathogenic strains in seeds (i.e., seed health testing), ensuring the crop productivity, quality, and safety.

Darbo objektas: tyrimams mėginiai imti iš sandėlių X ir XX, esančių Vilkaviškio rajone, iš viso paimta 30 miežių ir 30 kviečių mėginių. Darbo tikslas: nustatyti Fusarium spp. kitimą grūduose ir fuzariotoksinų dinamiką sandėliavimo metu bei įvertinti profilaktinių priemonių efektyvumą prieš Fusarium spp. plitimą grūduose. Tyrimo uždaviniai:nustatyti sandėliavimo metu grūdų (kviečių ir miežių) užsikrėtimą mikromicetais;įvertinti fuzariotoksinų (deoksinivalenolio, zearalenono, T–2 toksino) paplitimą grūduose sandėliavimo metu; įvertinti profilaktinių priemonių efektyvumą X ir XX ūkiuose prieš Fusarium spp. plitimą grūduose. Rezultatai ir aptarimas. Atlikus kiekybinį kviečių ir miežių užterštumą mikromicetų pradais, buvo nustatyta, kad didžiausias „Ūla“ veislės miežių užterštumas buvo nustatytas 2013 metų kovo mėnesį 113±10,4*103 KSV/g. Veislėje “Luokė” didžiausias užterštumas mikromicetų pradais buvo nustatytas 2012 metų kovo mėnesį –109±19,9*103 KSV/g. Didžiausias kviečių veislės „Triso“ užkrėstumas taip pat buvo nustatytas 2012 metų kovo mėnesį – 204±7,8*103 KSV/g, veislės „Munk“ didžiausias užterštumas buvo nustatytas taip pat 2012 metų kovo mėn. 128±10,8*103KSV/g. Lyginant sandėliuose X ir XX laikomus miežius „Ūla“ ir „Luokė“ Fusarium spp. paplitimas buvo: miežių „Ūla“ didžiausias vidinis užkrėstumas mikromicetų pradais siekė 80±0,0 proc. veislės „Luokė“ taip pat 80±0,0 proc. Didžiausias išorinis fuzarioze užkrėstumas veislėje “Ūla” siekė 73±0,44 proc. (sausio mėn. 2012 m.)... [toliau žr. visą tekstą] / The Object of the work: testing samples taken from granaries located in the X and XX Vilkaviškis district, taken 30 wheat and 30 barley samples. The aim of the work: changes in the grain and dynamics of fusariotoxins while granaring and to evaluate effectiveness of preventive measures against spreading of Fusarium spp. in grain. Reasearch objects:to assess fungi contamination in grain (wheat and barley) while granaring; to evaluate prevalence of fusariotoxins (deoxynivalenol, zearalenone, T–2 toxin ) in the grain while granaring;to evaluate effectiveness of preventive measures in X farms against spreading of Fusarium spp. in the grain. The results and their discussion: carried out quantitative wheat and barley contamination with fungi rudiment, found that ultimate „Ūla“ species barley contamination determined in 2013 March 113±10,4*103 KSV/g. Ultimate „Luokė“ species barley contamination with fungi rudiment determined 2012 March 109±19,9*103 KSV/g. Ultimate contamination of wheat species „Triso“ as well was determined 2012 March 204±7,8*103 KSV/g, mean while ultimate contamination of species „Munk“ was determined 2012 March 128±10,8*103KSV/g. Compared spreading in barley of Fusarium spp. in granaries X and XX species „Ūla“ and „Luokė“ prevalence found: ultimate contamination with fungi rudiment in barley „Ūla“ range 80±0,0 %, species „Luokė“ 80±0,0 %. Ultimate external contamination of fusariosis in species „Ūla“ range 73±0,44 % (2012 January) and 73±3,33 % (2012... [to full text]

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The genus Fusarium is characterized by hyaline filamentous fungi that cause a wide spectrum of infections predominantly in immunocompromised patients. These fungal infections show high rates of morbidity and mortality and are difficult to diagnosis, to prevent and to treat. The remarkable primary resistance to antifungal agents of this genus requires the search for new therapeutic possibilities. An attempt is a combination of drugs with different mechanisms of action. This study aimed to evaluate the in vitro susceptibility of Fusarium to conventional antifungal agents (amphotericin B, itraconazole, and voriconazole) and their combinations with no antifungal drugs (azithromycin, ciprofloxacin, fluvastatin, ibuprofen, metronidazole, and rifampicin) against 27 isolates of Fusarium spp. including the species: F. chlamydosporum (3), F. nygamai (1), F. oxysporum (6), F. proliferatum (2), F. solani (11), F. sporotrichoides (1), and F. verticillioides (3). Based on the protocol M38-A2 (CLSI, 2008) the technique of checkerboard was used for the assessment of associations. Alone, the MICs for amphotericin B ranged from 0.125 - 4 μg/ml; for voriconazole they ranged from 1 - >16 μg/ml, and for itraconazole all isolates showed MICs > 16 μg/ml. All combinations with amphotericin B showed synergistic interactions, and the most effective were amphotericin B plus ibuprofen (44.4%), amphotericin B plus metronidazole (40.7%), and amphotericin B plus ciprofloxacin (37%). No antagonistic interactions were observed for associations with amphotericin B. Similarly, all associations with voriconazole showed synergism, and the most significant associations were voriconazole plus ciprofloxacin (33.3%) and voriconazole plus metronidazole (33.3%). The antagonism was observed in all associations with voriconazole against F. verticillioides. The associations with itraconazole showed indifferent interactions for 100% of the isolates tested. These results demonstrate that the in vitro antifungal activity of the drug combination showed better results than the isolated one, except for associations with itraconazole. The most significant associations with amphotericin B and voriconazole deserve in vivo evaluations in order to verify their potential in the treatment of fusariosis. / O gênero Fusarium é caracterizado por fungos filamentosos hialinos que causam um amplo espectro de infecções predominantemente em pacientes imunocomprometidos. Estas micoses evidenciam elevados índices de morbidade e mortalidade e são de difícil diagnóstico, prevenção e tratamento. A marcante resistência primária deste gênero aos antifúngicos impõe a busca por novas possibilidades terapêuticas. Uma tentativa é a combinação entre fármacos com diferentes mecanismos de ação. Este estudo objetivou avaliar a suscetibilidade in vitro do gênero Fusarium a antifúngicos convencionais (anfotericina B, itraconazol e voriconazol) e associações destes com fármacos não antifúngicos (azitromicina, ciprofloxacina, fluvastatina, ibuprofeno, metronidazol e rifampicina) frente a 27 isolados de Fusarium spp., incluindo as espécies: F. chlamydosporum (3), F. nygamai (1), F. oxysporum (6), F. proliferatum (2), F. solani (11), F. sporotrichoides (1) e F. verticillioides (3). Com base no protocolo M38-A2 (CLSI, 2008) empregou-se a técnica de checkerboard para a avaliação das associações. Isoladamente, as CIMs para a anfotericina B variaram de 0,125 - 4 μg/ml; para o voriconazol variaram de 1 - >16 μg/ml e, para o itraconazol todos os isolados evidenciaram CIMs > 16 μg/ml. Todas as combinações com anfotericina B demonstraram interações sinérgicas, sendo que as mais eficazes foram: anfotericina B + ibuprofeno (44,4%), anfotericina B + metronidazol (40,7%) e anfotericina B + ciprofloxacina (37%). Não foram observadas interações antagônicas para as associações com anfotericina B. Similarmente, todas as associações com voriconazol demonstraram sinergismos; sendo que as associações mais significativas foram: voriconazol + ciprofloxacina (33,3%) e voriconazol + metronidazol (33,3%). O antagonismo foi observado em todas as associações com voriconazol frente a F. verticillioides. As associações com itraconazol evidenciaram interações indiferentes para 100% dos isolados testados. Estes resultados demonstram que a atividade antifúngica in vitro de fármacos combinados evidenciaram melhores resultados do que isolados, exceto para as associações com itraconazol. As associações mais relevantes com anfotericina B e voriconazol merecem avaliação in vivo, a fim de verificar o potencial das mesmas no tratamento da fusariose.

O presente estudo objetivou avaliar a microbiota fúngica e a ocorrência de micotoxinas por Cromatografia Líquida de Alta Eficiência acoplada à Espectrometria de Massas em amostras de grãos de trigo recém-colhidas e armazenadas. Os resultados revelaram a predominância do gênero Alternaria nas amostras de todas as coletas, seguido de Epicoccum (12,6%), Fusarium (8,3%) e mais 16 outros gêneros de fungos filamentosos. As espécies de Fusarium e Alternaria foram identificadas utilizando métodos moleculares, sendo F. graminearum e A. alternata as espécies mais frequentes. De 70 amostras, 69 (98,6%) estavam contaminadas com a toxina DON (210-2910 ppb) e 3 (4,3%) amostras contaminadas com a toxina ZEA (20-30,1 ppb). O nível de contaminação por DON é inferior aos limites estabelecidos recentemente pela legislação brasileira (3000 ppb), porém superam os limites da Comunidade Européia (1750 ppb). É prudente que se realize um monitoramento contínuo de grãos de trigo a fim de avaliar a exposição dos consumidores às contaminações e estabelecer diretrizes de segurança alimentar. / The present study aimed to evaluated the mycoflora and occurrence of mycotoxins by high performance liquid chromatography coupled to tandem mass in freshly harvested and stored wheat samples. The results showed the predominance of genus Alternaria in all samples, followed by Epicoccum (12.6%), Fusarium (8.3%) and over 16 other genera of filamentous fungi. The species of Fusarium and Alternaria were identified using molecular methods, and F. graminearum and A. alternata were the most frequent species. Of 70 samples, 69 (98.6%) were contaminated with toxin DON (210-2910 ppb), and 3 (4.3%) samples contaminated with the toxin ZEA (20-30.1 ppb). The level of DON contamination is below of the limits recently established by Brazilian legislation (3000 ppb), but exceed the limits of the European Community (1750 ppb). It is prudent to perform a continuous monitoring of wheat to assess consumer exposure to contaminants and establish guidelines for food safety.

O presente estudo objetivou avaliar a microbiota fúngica e a ocorrência de micotoxinas por Cromatografia Líquida de Alta Eficiência acoplada à Espectrometria de Massas em amostras de grãos de trigo recém-colhidas e armazenadas. Os resultados revelaram a predominância do gênero Alternaria nas amostras de todas as coletas, seguido de Epicoccum (12,6%), Fusarium (8,3%) e mais 16 outros gêneros de fungos filamentosos. As espécies de Fusarium e Alternaria foram identificadas utilizando métodos moleculares, sendo F. graminearum e A. alternata as espécies mais frequentes. De 70 amostras, 69 (98,6%) estavam contaminadas com a toxina DON (210-2910 ppb) e 3 (4,3%) amostras contaminadas com a toxina ZEA (20-30,1 ppb). O nível de contaminação por DON é inferior aos limites estabelecidos recentemente pela legislação brasileira (3000 ppb), porém superam os limites da Comunidade Européia (1750 ppb). É prudente que se realize um monitoramento contínuo de grãos de trigo a fim de avaliar a exposição dos consumidores às contaminações e estabelecer diretrizes de segurança alimentar. / The present study aimed to evaluated the mycoflora and occurrence of mycotoxins by high performance liquid chromatography coupled to tandem mass in freshly harvested and stored wheat samples. The results showed the predominance of genus Alternaria in all samples, followed by Epicoccum (12.6%), Fusarium (8.3%) and over 16 other genera of filamentous fungi. The species of Fusarium and Alternaria were identified using molecular methods, and F. graminearum and A. alternata were the most frequent species. Of 70 samples, 69 (98.6%) were contaminated with toxin DON (210-2910 ppb), and 3 (4.3%) samples contaminated with the toxin ZEA (20-30.1 ppb). The level of DON contamination is below of the limits recently established by Brazilian legislation (3000 ppb), but exceed the limits of the European Community (1750 ppb). It is prudent to perform a continuous monitoring of wheat to assess consumer exposure to contaminants and establish guidelines for food safety.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Erva mate (Ilex paraguariensis A. St.-Hil.) is a species widely cultivated in southern Brazil and adjacent countries, whose leaves and fine branches, appropriately prepared, offer the mate-tea, the most popular tea consumed in Brazil and exported to all over the world. root-rot is the main disease of this species in Brazil and may attack plantules and seedlings in nurseries as well as adult trees in orchards. The disease is caused by Fusarium spp., besides Pythium sp. and Rhizoctonia sp. causing serious damages due to the root system destruction, it causes, in the most serious cases the death of the plant. The incidence and the severity of the disease might be influenced by the cultivation methods and management of the orchard, with the use of mineral fertilizers without any technical criteria or the absence of fertilization, soil liming and orchards cultivation under the sun. In order to verify such hypothesis, 25 rural estates were marked in different counties of Vale do Taquari area in the state of Rio Grande do Sul BR. These areas had some orchards with symptoms of the disease and others in healthy conditions. Information about the crop and management characteristics, as well as soil for chemical and biological analysis, were collected and correlated through Pearson and outspread in direct and indirect effects through Path Analysis. In the nurseries, the disease incidence might be correlated to the contamination of the seed and the transmitted pathogens besides causing the death of the seedling may also have been transmitted to health seedlings, and they might had been transported to the field, contaminated areas which were previously free from the pathogen. Some practices applied by the farmers may cause the increase in the incidence of pathogens in the seeds and seedlings. In order to verify such hypothesis, some nurseries have been selected in the area of Vale do Taquari RS, where some samples of seeds, plantules, seedlings and substrata were collected in order to analyze the inoculation potential of the pathogens in each sort of sample. From the analysis of the substrata, seeds, seedlings different fungi colonies of the genre Fusarium were isolated, purified and stored for pathogenicity tests and, Trichoderma, for isolated selection with potential Fusarium antagonist. Moreover, experiments were installed in 2 nurseries, aiming at testing the benefits of commercial chemical (Captan SC®) and biological (Agrotrich® e Trichodel®) products, in the seed treatment, aiming at controlling the incidence of the disease on the seedbed. In the orchards, among the studied variables, it was noticed that the organic matter is the most influential over the Fusarium population in the soil and a linear positive correlation was obtained. Besides this variable, the calcium and phosphorus contends also have some sort of influence over the Fusarium population, however, in a less significant way. In the nurseries, the high percentage of seeds contaminated by Fusarium and Rhizoctonia was noticed. It was also noticed that the contamination begins in the flower and fruit phase. It was also observed that the technique of seed processing and stratification applied by the farmers, contribute to the increase in the incidence of pathogens. Besides the seeds, it was also noticed that the plantules and seedlings at the end of the nursery cycle, present pathogen contamination in their roots, although they did not present root-rot symptoms. The products Captan SC®, Agrotrich® and Trichodel® applied on the seed treatment, before the sowing, were not efficient in the Fusarium and Rhizoctonia control. In the Trichoderma spp. selection as potential antagonist to Fusarium, it was observed that SP-SFE-T1 isolated present high antagonic potential in in vitro tests. / A erva-mate (Ilex paraguariensis A. St.-Hil.) é uma espécie amplamente cultivada no sul do Brasil e países vizinhos, cujas folhas e galhos finos, preparados segundo método apropriado, fornecem o mate ou chimarrão, o mais popular chá consumido no Brasil e exportado para todo o mundo. A podridão-de-raízes é a principal doença da espécie no Brasil, podendo atacar plântulas e mudas no viveiro, bem como, árvores adultas em ervais. A doença é causada por Fusarium spp., além de Pythium sp. e Rhizoctonia sp. e provoca sérios danos decorrentes da destruição do sistema radicular, ocasionando, nos casos mais graves, morte da planta. Suspeita-se que a incidência e a severidade da doença são influenciadas pelos métodos de cultivo e por práticas de manejo do erval, como aplicação de adubos minerais sem critérios técnicos ou ausência de adubação, calagem do solo e cultivo de ervais a pleno sol. Para verificar tal hipótese, foram demarcadas 25 propriedades rurais, em diferentes municípios da região do Vale do Taquari-RS, as quais possuíam ervais com sintomas da doença, e outras com ervais sadios. Nesses ervais, foram coletadas informações a respeito das características de cultivo e manejo, assim como, solo para análise química e biológica. Estas informações foram correlacionadas entre si através da correlação de Pearson e desdobradas em efeitos diretos e indiretos através da Análise de Trilha. Nos viveiros, suspeita-se que a incidência da doença está correlacionada à contaminação das sementes utilizadas e que, patógenos transmitidos por sementes, além de causar mortalidade de mudas, podem ser transmitidos a mudas sadias e, estas, serem transportadas para o campo, contaminando áreas livres do patógeno. Além disso, algumas práticas utilizadas pelos viveiristas podem ocasionar aumento da incidência de patógenos nas sementes e mudas. Para verificar tal hipótese, foram demarcados viveiros na região do Vale do Taquari-RS, onde foram coletadas amostras de sementes, de plântulas, de mudas e de substrato para analisar o potencial de inóculo de patógenos presente em cada tipo de amostra. A partir das análises do substrato, das sementes e das mudas, diferentes colônias de fungos do gênero Fusarium foram isoladas, purificadas e armazenadas, para testes de patogenicidade e, Trichoderma, para seleção de isolados com potencial antagonista ao Fusarium. Além disso, foram instalados experimentos, em dois viveiros, a fim de testar a eficiência dos produtos comerciais, químico (Captan SC®) e biológico (Agrotrich® e Trichodel®), no tratamento de sementes, visando o controle da incidência da doença nas sementeiras. Nos ervais, entre as variáveis estudadas, verificou-se que a matéria orgânica é a que mais influencia na população de Fusarium do solo, obtendo-se uma correlação linear positiva. Além desta variável, os teores de cálcio e de fósforo no solo também exercem certa influencia na população de Fusarium, mas de forma menos significativa. Nos viveiros, constatou-se alta porcentagem de sementes contaminadas por Fusarium e Rhizoctonia e que, a contaminação começa já na fase de flores e frutos. Observou-se também, que a técnica de beneficiamento e estratificação das sementes, utilizada atualmente pelos viveiristas, contribui para o aumento da incidência de patógenos. Além das sementes, observou-se que plântulas e mudas no final do ciclo de viveiro, apresentam contaminação por patógenos nas suas raízes, mesmo que não apresentavam sintomas de podridão-de-raízes. Os produtos Captan SC®, Agrotrich® e Trichodel® utilizados no tratamento das sementes, previamente a semeadura, não foram eficientes no controle de Fusarium e Rhizoctonia. Na seleção de Trichoderma spp. com potencial antagonista ao Fusarium observou-se que o isolado SP-SFE-T1 apresentou alto potencial antagônico em testes in vitro .