Zymoseptoria tritici is an ascomycete fungus that causes Septoria tritici leaf blotch disease, which is one of the most devastating diseases of wheat. The lack of molecular tools has withheld functional genomics and consequently has left extensive gaps in the knowledge of the biology of infection by Z. tritici. The current research was conducted to develop molecular tools in order to facilitate forward and reserves genetic screens in Z. tritici. These tools include an optimised genetic manipulation protocol, the Z. tritici strains that provide high frequency targeted genome manipulations, a strategy for gene overexpression and protein tagging, and regulatable promoters for controlled gene expression in Z. tritici. The regulatable promoters served to reveal that the Z. tritici β-(1,3)- glucan synthase (BGS1) gene encoded an essential protein, which regulated cell wall stress tolerance and was therefore, a potential drug target. In addition, these molecular tools revealed a virulence-associated role of the glyoxylate cycle in Z. tritici as inactivation of this pathway impeded pre-penetration morphogenesis, which was restored by exogenous glucose application. This result implied that Z. tritici engaged the glyoxylate cycle to produce energy though gluconeogenesis by channelling the by-products of lipolysis. This significance of the glyoxylate cycle during initiation of the bi-phasic infection cycle suggests that Z. tritici is not a hemibiotroph, but a necrotrophic pathogen with an extended asymptomatic phase of infection. Overall, the molecular tools developed in this study will facilitate large-scale functional genomic analyses to interrogate the biology of infection by Z. tritici. The resulting data will inform the development of durable control strategies to combat Z. tritici outbreaks.

Fusarium head blight (FHB) caused by Fusarium graminearum and Septoria tritici blotch (STB) caused by Septoria tritici are economically important wheat diseases in Ontario. Both reduce yield, FHB is associated with mycotoxin accumulation including deoxynivalenol (DON). Different F. graminearum chemotypes produce either DON/15-acetyldeoxynvialenol (ADON) or DON/3-ADON. The majority (97.5%) of F. graminearum isolates collected from commercial fields across Ontario were 15-ADON chemotype, the remaining were 3-ADON. In inoculated field experiments 3-ADON chemotypes were more aggressive and toxic compared with 15-ADON chemotypes as measured by FHB symptoms and DON content. In inoculated field experiments with a population derived from ‘RCATL33’ and ‘RC Strategy’ soft red winter wheat parents, genetic resistance was more effective than fungicide application at controlling FHB. Field trials with the hard red winter wheat population derived from ‘Maxine’ and ‘FTHP Redeemer’ parents revealed that STB and FHB phenotypic resistance had no negative impact on grain yield in the absence of disease.

Septoria ampelina causes a disease of grapes known as septoria leaf spot. This study was done to determined which of the fungicides currently used to control the various diseases of grapes, plus one experimental fungicide, is the most effective in controlling septoria leaf spot. Both in vitro and in vivo methods were used. In vivo studies examined the systemic and/or protectant activities of the fungicides. The systemic and protectant fungicides included Bayleton, Benlate, Elite (an experimental fungicide), Nova, Rovral and Rubigan. The protectant only fungicides included Captan, Dithane and Kocide. In vitro tests to determine the minimum inhibitory concentration (MIC) for each fungicide (e.g., the concentration of the fungicide that prevents the fungus from forming colonies on the PEA-fungicide medium), indicate that Benlate (MIC = 0.1 ppm) and Elite (MIC = 1.0 ppm) have the greatest potential'to control septoria leaf spot of grape. These are followed by Dithane, Nova and Rubigan (MIC = 2.0), which in turn are followed by Bayleton and Captan (MIC = 50.0 ppm). Kocide and Rovral did not inhibit fungal growth at concentrations up through 100 ppm. Although all the fungicides tested significantly reduced the incidence of septoria leaf spot in vivo, Benlate and Elite were the most effective fungicides (both in systemic and protectant application). / Department of Biology

Zugl.: Kiel, Univ., Diss., 2007

University, Diss., 2005--Kiel.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This study aimed to evaluate the severity of occurrence of septoria leaf spot in sunflower, its association with meteorological variables and its effect on yield of field irrigated sunflower. The experiments were conducted in Santa Maria - RS during the 2008 spring season and during the 2009 fall growing season, with sowings in September and in February, respectively. Observations of severity of septoria leaf spot were made throughout the crop cycle, and with a disease forecasting system different times for fungicide applications have been identified. Results show that a sequence of rainy days, with favorable temperatures to the pathogen, tend to contribute to the development of septoria leaf spot in sunflower. In contrast, when water needed by plants is restored by irrigation, even temperature is favorable to the pathogen, disease development rate is lower than during and within 10 days of rainy periods. There were observed differences in septória leaf spot severity between treatments with and without fungicide application, but were not related to the yield of sunflower achenes. Fungicide application according to the different treatments did not significantly affect achene yield either. Therefore, significant differences in the variables that represent the progression of the disease do not necessarily imply in significant differences in yield. / Neste trabalho objetivou-se verificar a severidade de ocorrência de mancha de septória em girassol, sua associação aos elementos meteorológicos e seu efeito na produtividade do girassol cultivado a campo sob irrigação. Os experimentos foram conduzidos em Santa Maria RS durante a safra de 2008 e safrinha de 2009, com semeaduras em setembro e fevereiro, respectivamente. Foram realizadas observações de severidade de mancha de septória durante todo o ciclo da cultura e, com o auxílio de um sistema de previsão de doenças, foram definidos diferentes momentos para as aplicações de fungicida. Os resultados demonstram que sequencias de dias chuvosos, com temperatura favorável ao patógeno, tendem a contribuir para o desenvolvimento da mancha de septória no girassol. Em compensação, quando a água necessária às plantas é reposta por meio de irrigações, mesmo que a temperatura seja favorável ao patógeno, a taxa de desenvolvimento da doença é menor do que durante e até 10 dias após períodos chuvosos. Foram verificadas diferenças de severidade observada de mancha de septória entre tratamentos com e sem aplicação de fungicida, mas essas não apresentaram relação significativa com a produtividade de aquênios do girassol. A aplicação de fungicida, conforme os diferentes tratamentos, também não apresentou associação significativa com a produção de aquênios. Portanto, diferenças significativas nas variáveis que representam a progressão da doença não implicam necessariamente em diferenças significativas de produtividade.

Septoria musiva (téléomorphe Mycosphaerella populorum) est un Ascomycète responsable de chancres sur tronc et jeunes branches en peupleraies et de taches foliaires en peupleraies et forêts. S. populicola (M. populicola) est responsable de taches foliaires sur peupliers. L’objectif de mon projet consiste à mettre en place un système de transformation à l’aide d’Agrobacterium tumefaciens pour ces deux champignons. A. tumefaciens est la bactérie causant la galle du collet, mais qui est utilisée couramment lors de transformation de végétaux et de champignons. Une première expérience a permis d’obtenir des transformants pour S. musiva avec le plasmide pPT1, mais aucun transformant n’a été obtenu pour S. populicola. Par la suite, un autre plasmide a été utilisé : pPL1. Cependant aucune souche transformée n’a pu être obtenue pour S. musiva, et S. populicola, malgré la vérification de différents paramètres. L’absence de transformant chez S. populicola peut être attribuée à un nombre insuffisant de conidies, tandis que pour S. musiva, un nombre insuffisant de bactéries ou un protocole de transformation non optimal pourrait expliquer les échecs successifs. / Seporia musiva (Mycosphaerella populorum) is an Ascomycota which causes canker and leafspot on hybrid poplar. S. populicola (M. populicola) only causes leafspot. The aim of my project was to transform these two fungi with Agrobacterium tumefaciens, a bacterium which causes Crown gall, and is commonly used to transform plant and fungi in laboratory. In a first experiment, transformation using plasmid pPT1 were successful for S. musiva, but not for S. populicola. However, no transformants were obtained from either S. musiva and S. populicola in subsequent experiments in which plasmid pPL1 was used and different parameters were tested. A possible explanation for the inhability to obtain transformants from S. populicola is the low number of conidia available for transformation experiments. In the case of S. musiva, low number of bacterial cells and non optimal protocols might explain negative results observed.

No description available.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The occurrence of disease has been one of the main problems of the sunflower crop over the years. The objective of this study was to evaluate the effect of irrigation and the application of fungicides on the occurrence of diseases and yield of achenes of two genotypes of sunflower crop in the main and second crop season in the central region of Rio Grande do Sul. The experiments were carried out at Plant Science Department of the Federal University of Santa Maria, Santa Maria, RS, Brazil during the main season at 2007 and the second crop season of 2008. Following growth and development of plants during the crop season through phenometrical and phenological observations. The meteorological data were collected in the center of the experimental area with an automatic weather station and psychrometric pairs at different levels. Twelve treatments were used arranged in a completely randomized design with four replications. The treatments consisted of irrigated and non irrigated controls and different forms of protection with fungicide according to the accumulated severity values (SV) estimated by the FAST (VS = 16, 22, 28) without irrigation and with irrigation and protection with fungicide with 16 VS. The theoretical values of severity (VS) were calculated using the FAST system, considering the duration of the period with relative humidity greater than 90% and air temperature during this period. When the values of the severity of the treatment were achieved the fungicide was applied, and a new count of VS began. The progress of the disease was analyzed based on weekly observations of the severity of the symptoms of the disease in three plants per plot. It was found that irrigation increases the productivity of achenes of sunflower cultivation in the main season, provided that weather conditions are not favorable for the occurrence of the alternaria blight and Septoria leaf blight, or that fungicides to control these diseases are applied before flowering. In the second crop season the effect of irrigation on yield of achenes is negative due to higher occurrence of the alternaria blight and Septoria leaf blight in sunflower. The prediction of the occurrence of diseases in sunflower can be made from weather elements, but adjustments are needed to define the most appropriate criteria. / A ocorrência de doenças vem sendo um dos principais problemas da cultura do girassol ao longo dos anos. O objetivo deste trabalho foi avaliar o efeito da irrigação e da aplicação de fungicidas na ocorrência de doenças e na produtividade de aquênios de dois genótipos de girassol em cultivos de safra e safrinha, na região central do Rio Grande do Sul. Os experimentos foram conduzidos junto ao Departamento de Fitotecnia da Universidade Federal de Santa Maria, Santa Maria, nos períodos de safra de 2007 e safrinha de 2008, acompanhando-se o crescimento e o desenvolvimento das plantas no decorrer do ciclo da cultura através de observações fenométricas e fenológicas. Os dados meteorológicos foram coletados no centro da área experimental com uma estação meteorológica automática e com pares psicrométricos instalados em diferentes níveis. Foram utilizados doze tratamentos arranjados no delineamento inteiramente casualizado, com quatro repetições. Os tratamentos constaram de testemunha irrigada e não irrigada e de diferentes esquemas de proteção com fungicida em função dos valores acumulados de severidade (VS) estimados pelo sistema FAST (VS = 16, 22, 28) sem irrigação, bem como, com irrigação e proteção com fungicida com 16 VS. Os valores de severidade teórica (VS) foram calculados através do sistema FAST, considerando a duração do período com umidade relativa maior do que 90% e a temperatura do ar nesse período. No momento em que os respectivos valores de severidade do tratamento foram alcançados foi realizada a aplicação do fungicida e iniciou-se uma nova contagem de VS. O progresso da doença foi analisado com base nas observações semanais da severidade dos sintomas da doença em três plantas por parcela. Verificou-se que a irrigação aumenta a produtividade de aquênios de girassol no cultivo de safra, desde que as condições meteorológicas não sejam favoráveis para a ocorrência de mancha de alternaria e septoriose, ou desde que se aplique fungicidas para o controle dessas doenças antes da floração. Na safrinha o efeito da irrigação na produtividade de aquênios é negativo devido à maior ocorrência de mancha de alternaria e septoriose em girassol. A previsão de ocorrência de doenças em girassol pode ser feita a partir de elementos meteorológicos, mas são necessários ajustes para definir os critérios mais adequados.

Made available in DSpace on 2016-12-08T16:44:33Z (GMT). No. of bitstreams: 1 PGPV10MA034.pdf: 1439904 bytes, checksum: 4db5cc7ffec224395655a5207d466072 (MD5) Previous issue date: 2010-12-08 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Tomato plants (Solanum lycopersicum L.) cultivated under conventional production systems are frequently disturbed by insects and diseases. Synthetic organic pesticides that are used to manage tomato crops have been harmful to human being and environment as well. Fruits of tomato are very sensitive to handling and its quality is highly influenced by the crop system and post-harvest practices. The objective of this research was to evaluate the effect of high dilution preparations to manage pest and disease, and post-harvest conservation of tomatoes under organic production systems. Experiments were conducted as follow: a) Two experiments under field conditions; b) one experiment in greenhouse; c) one bio-assay concerning post-harvesting; d) twelve bio-assays in vitro conditions. The experiments were conducted in the Lages Experimental Station area of EPAGRI and at Centro Agroveterinario of University of Santa Catarina State, SC. Treatments consisted of high dilutions of Staphysagria, Arsenicum album, Sulphur at 12CH (centesimal hahnemaniana dilution), and Arnica montana, Sulphur, tomato, and jua (Solanum aculeatissimum), nosodes at 12 and 24DH. Bourdoux mixture at 0.3%, Cupric formulation EEC at 50 ppm, and Bacillus thuringiensis were included as standard treatments. Data were from field experiments consisted of septoriosis incidence (Septoria lycopersici), insect occurrence, damage caused by Agathomerus sellatus, yields, and fruit quality attributes. Data analysis was performed throughout statistical package. Results showed that Staphysagria 12CH and Arnica Montana 12DH could increase tomato fruit weigh. Damage caused by tomato caterpillars were reduced by spraying Sulphur 12CH and Bacillus thuringiensis. B. thuringiensis reduced also the incidence of septoriosis. High dilution preparation interfered to insect occurrence and reduced the damage of Agathomerus sellatus in the stages of larvae and adults. Tomato plants treated by jua nosodes at 12 and 24CH increased the SST (° Brix) contents, which gives better qualities of processing and palatability, as well. In the greenhouse experiment, it was evaluated the treatments of Arnica montana, Sulphur, tomato and jua nosodes, all at 12 and 24DH dinamization. Bourdoux mixture at 0.3% and cupric formulation EEC at 50 ppm were considered as standard treatments. It was observed that tomato nosodes at 12DH and 24DH supressed the septorioris incidence. In the post-harvest bio-assay, fruits were treated with Calcarea carbonica at 6, 12, 24CH dinamizations. The evaluation was concerning chemical contents and physical attributes. Calcarea carbonica post-harvest treatment did not affected the acidity, SST (° Brix), hardness or the weight losses of tomato fruits. However, Calcarea carbonica 24CH delayed the fruit maturation in such way that the kind sauce fruit was reduced. In the laboratory bio-assays the follow high dilution preparations were studied: Staphysagria, Arsenicum album, and Nitricum acidum at 6, 12, 25, 30, 50, 60, 80, and 100CH 11 dinamizations. All preparations were tested in two media combined by two application methods into Petry dishes with colonies of the fungus Alternaria solani. Bioassay was studied by measuring the diameter of the colonies. The measurements were made from 24h until the 10th day after install the assays. It was observed that the media with basic composition were more suitable to screening high dilution preparations against A. solani before to test in the field. The application method of high dilution preparations over the fungus colony was better than incorporated one. The use of high dilution preparations has the potential effect to replace pesticide used on tomato crops and it would be a suitable management strategy to fill legal requirements for organic production systems. / O tomateiro (Solanum lycopersicum L.) sob sistema de produção convencional está constantemente sujeito à pragas e doenças. Pesticidas orgânicos sintéticos usados para seu manejo podem causar graves pertubações ao meio ambiente e a saúde humana. Frutos de tomateiro também são sensíveis ao manuseio e sua qualidade é afetada pelo sistema de cultivo e pelas práticas de conservação pós-colheita. O objetivo deste trabalho foi avaliar o efeito de preparados em altas diluições no manejo fitossanitário e pós-colheita da cultura do tomateiro sob sistema orgânico de produção. Foram conduzidos (a) dois experimentos em condições de campo, (b) um experimento em casa de vegetação, (c) um ensaio de conservação pós-colheita em laboratório e (d) doze bioensaios in vitro. Os experimentos foram conduzidos na Estação Experimental da EPAGRI de Lages e, no Centro de Ciências Agroveterinárias da UDESC. Os tratamentos avaliados nos experimentos a campo foram os preparados em altas diluições de Staphysagria, Arsenicum album, Sulphur na dinamização 12CH (centesimal hahnemaniana); Arnica montana, Sulphur, nosódios de tomateiro e de juá (Solanum aculeatissimum), nas dinamizações 12 e 24DH (decimal hahnemaniana). Calda bordalesa 0,3%, Calda cúprica EEC a 50 ppm e Bacillus thuringiensis foram incluídos em doses ponderais e considerados tratamentos padrões. Nos experimentos a campo avaliou-se a incidência de septoriose (Septoria lycopersici), ocorrência e danos por insetos, produtividade e atributos químicos de qualidade dos frutos. A análise dos dados mostrou que os preparados Staphysagria 12CH e Arnica montana 12DH proporcionaram a maior peso de frutos. Danos causados por brocas foram reduzidos com a aplicação de Sulphur 12CH igualando a Bacillus thuringiensis. B. thuringiensis também reduziu a incidência de septoriose. Observou-se que os preparados em altas diluições interferiram na ocorrência de insetos em plantas de tomateiro e reduziram os danos causados por Agathomerus sellatus, tanto na fase larval quanto na fase adulta. Tomateiros tratados com nosódio de juá 12 e 24DH tiveram incremento no teor de SST (° Brix) dos frutos, atributo que melhora a palatabilidade e a qualidade para a industrialização. No experimento em casa de vegetação, avaliou-se Arnica montana, Sulphur, nosódios de tomateiro e de juá, nas dinamizações 12 e 24DH. Calda bordalesa 0,3% e calda cúprica EEC a 50 ppm também foram incluídas em doses ponderais e considerados tratamentos padrões. Observou-se que o nosódio de tomateiro na 12DH e 24DH suprimiram a incidência de septoriose nas plantas tratadas. No ensaio em laboratório de conservação pós-colheita, frutos foram tratados com Calcarea carbonica nas dinamizações 6, 12, 24CH. Avaliou-se atributos químicos e físicos dos frutos. Calcarea carbonica em tratamento pós-colheita não interferiu na acidez, SST (° Brix), firmeza e perda de massa fresca dos frutos. Embora, Calcarea9 carbonica 24CH retardasse a formação de frutos do tipo molho. Nos estudos in vitro foram avaliados os preparados Staphysagria, Arsenicum album e Nitricum acidum nas dinamizações 6, 12, 25, 30, 50, 60, 80 e 100CH, em meios de cultivo básico e enriquecido e, em dois métodos de aplicação. Nos bioensaios foi avaliado o diâmetro das colônias do fungo Alternaria solani iniciando-se 24 horas após a instalação do ensaio e estenderam-se até o décimo dia. Observou que meios de cultivo com composição básica foram mais adequados para o screening de preparados em altas diluições e suas dinamizações, em estudos in vitro com A. solani. A aplicação dos preparados em altas diluições sobre a colônia do fungo foi o método mais adequado para estudos in vitro. Preparados em altas diluições tem potencial para serem eficazes na substituição de agrotóxicos que são utilizados na cultura do tomateiro, e poderiam ser adequados para preencherem requisito legal em sistemas orgânicos de produção