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Made available in DSpace on 2014-06-11T19:35:01Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-05-25Bitstream added on 2014-06-13T20:25:43Z : No. of bitstreams: 1 passador_mm_dr_botfca.pdf: 2195581 bytes, checksum: b49ee0b8f7df05ffdf472a2785c1e683 (MD5) / Muitas espécies de eucalipto são cultivadas no mundo todo e muitos patógenos evoluíram ou se adaptaram á cultura, principalmente fungos, desde a fase de viveiro até os plantios adultos. A mancha de micosferela é uma das principais doenças e o Eucalyptus globulus uma das espécies mais suscetíveis. O presente estudo foi iniciado a partir de isolamentos monospóricos de espécies fúngicas associadas à mancha de micosferela a partir de folhas e ramos de E. globulus provenientes de Bagé-RS, Pedras Altas-RS, Botucatu-SP, Jacareí-SP e Itapeva-SP, que possibilitou a obtenção de 46 isolados, que foram observados quanto à forma de germinação e crescimento micelial. A determinação das espécies deu-se por meio de PCR com primers da região genômica ITS1 e ITS4 e sequenciamento (vide capítulo 1). Como resultado, várias espécies foram encontradas e descritas. Mudas de E. globulus foram inoculadas pelo método da exposição de mudas sadias à folhas com sintomas de Teratosphaeria nubilosa, por ejeção de ascósporos, em casa de vegetação. Estas mudas foram avaliadas e folhas com os sintomas do fungo foram coletadas a partir da terceira semana até a décima terceira semana da inoculação. Para realização de cortes e estudos histológicos, que permitiram observar a formação dos pseudotécios desde o seu início três semanas após a inoculação, as hifas ascógenas dentro do pseudotécio após nove semanas e a formação das ascas e ascósporos após 11 e 13 semanas, respectivamente (vide capítulo 2). Através de estudos anatômicos, verificou-se que as folhas adultas apresentaram menor intensidade dos sintomas, o que pode estar relacionado com a compactação das células do parênquima, enquanto que as folhas jovens apresentam espaços intercelulares no parênquima lacunoso, no parênquima paliçádico e na câmara subestomática... / Many Eucalyptus species are grown worldwide, and many pathogens have evolved and adapted to the culture. The cultivation of eucalyptus is affected by a number of diseases. Many pathogens occur in several eucalypt species, especially fungi, from the nursery to the planting adults. The Mycosphaerella leaf disease is a major disease and Eucalyptus globulus one of the most susceptible species. This study consisted of spore isolates of fungal species associated with Mycosphaerella leaf disease from leaves and stems of E. globulus from Bage-RS, Pedras Altas-RS, Botucatu-SP, Jacareí-SP, Itapeva-SP, which allowed the collection of 46 isolatesm sequenced (see Chapter 1). As a result, several species were found and described. Seedlings of E.globulus were inoculated by exposure to leaves of healthy seedlings with symptoms of Teratosphaeria nubilosa, for ejection of ascospores in the greenhouse. Seedlings were evaluated, and leaves with the symptoms of the fungus were collected from the third week up to thirteenth week of inoculation. To carry out studies and histological sections, which allowed the formation of the pseudothecia from its beginning three weeks after inoculation, the formation of the ascogenous hyphae within pseudothecia after nine weeks, and the formation of asci and ascospores after 11 and 13 weeks, respectively (see Chapter 2). Through anatomical studies, it was found that if the adult leaves had a lower intensity of symptoms, which may be related to compression of the parenchyma cells, while the young leaves have intercellular spaces in the spongy parenchyma, palisade parenchyma and in substomatal chambers facilitating the formation of stroma (see Chapter 3). Essential oils of leaves and young adults, healthy and stain micosferela were extracted by hydrodistillation and analyzed by gas chromatography-mass spectrometry. The data of chemical composition and the respective percentages... (Complete abstract click electronic access below)

Orientador: Edson Luiz Furtado / Banca: Christiane Ceriani Aparecido / Banca: Celso Garcia Auer / Banca: Roberto Antonio Rodella / Banca: Marli Teixeira de Almeida Minhoni / Resumo: Muitas espécies de eucalipto são cultivadas no mundo todo e muitos patógenos evoluíram ou se adaptaram á cultura, principalmente fungos, desde a fase de viveiro até os plantios adultos. A mancha de micosferela é uma das principais doenças e o Eucalyptus globulus uma das espécies mais suscetíveis. O presente estudo foi iniciado a partir de isolamentos monospóricos de espécies fúngicas associadas à mancha de micosferela a partir de folhas e ramos de E. globulus provenientes de Bagé-RS, Pedras Altas-RS, Botucatu-SP, Jacareí-SP e Itapeva-SP, que possibilitou a obtenção de 46 isolados, que foram observados quanto à forma de germinação e crescimento micelial. A determinação das espécies deu-se por meio de PCR com primers da região genômica ITS1 e ITS4 e sequenciamento (vide capítulo 1). Como resultado, várias espécies foram encontradas e descritas. Mudas de E. globulus foram inoculadas pelo método da exposição de mudas sadias à folhas com sintomas de Teratosphaeria nubilosa, por ejeção de ascósporos, em casa de vegetação. Estas mudas foram avaliadas e folhas com os sintomas do fungo foram coletadas a partir da terceira semana até a décima terceira semana da inoculação. Para realização de cortes e estudos histológicos, que permitiram observar a formação dos pseudotécios desde o seu início três semanas após a inoculação, as hifas ascógenas dentro do pseudotécio após nove semanas e a formação das ascas e ascósporos após 11 e 13 semanas, respectivamente (vide capítulo 2). Através de estudos anatômicos, verificou-se que as folhas adultas apresentaram menor intensidade dos sintomas, o que pode estar relacionado com a compactação das células do parênquima, enquanto que as folhas jovens apresentam espaços intercelulares no parênquima lacunoso, no parênquima paliçádico e na câmara subestomática... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Many Eucalyptus species are grown worldwide, and many pathogens have evolved and adapted to the culture. The cultivation of eucalyptus is affected by a number of diseases. Many pathogens occur in several eucalypt species, especially fungi, from the nursery to the planting adults. The Mycosphaerella leaf disease is a major disease and Eucalyptus globulus one of the most susceptible species. This study consisted of spore isolates of fungal species associated with Mycosphaerella leaf disease from leaves and stems of E. globulus from Bage-RS, Pedras Altas-RS, Botucatu-SP, Jacareí-SP, Itapeva-SP, which allowed the collection of 46 isolatesm sequenced (see Chapter 1). As a result, several species were found and described. Seedlings of E.globulus were inoculated by exposure to leaves of healthy seedlings with symptoms of Teratosphaeria nubilosa, for ejection of ascospores in the greenhouse. Seedlings were evaluated, and leaves with the symptoms of the fungus were collected from the third week up to thirteenth week of inoculation. To carry out studies and histological sections, which allowed the formation of the pseudothecia from its beginning three weeks after inoculation, the formation of the ascogenous hyphae within pseudothecia after nine weeks, and the formation of asci and ascospores after 11 and 13 weeks, respectively (see Chapter 2). Through anatomical studies, it was found that if the adult leaves had a lower intensity of symptoms, which may be related to compression of the parenchyma cells, while the young leaves have intercellular spaces in the spongy parenchyma, palisade parenchyma and in substomatal chambers facilitating the formation of stroma (see Chapter 3). Essential oils of leaves and young adults, healthy and stain micosferela were extracted by hydrodistillation and analyzed by gas chromatography-mass spectrometry. The data of chemical composition and the respective percentages... (Complete abstract click electronic access below) / Doutor

Doctor of Philosophy / Department of Plant Pathology / William W. Bockus / Septoria tritici blotch caused by Mycosphaerella graminicola (anamorph Septoria tritici), is an important disease of wheat worldwide capable of reducing yields by as much as 30 to 40%. In Kansas, the disease is widespread and losses in individual fields can exceed 25%. This study examined the genetic structure of Kansas populations of M. graminicola at different spatial scales (micro-plot, macro-plot, and statewide) using amplified fragment length polymorphism (AFLP) markers. Three primer pairs were used to resolve 174 polymorphic loci from 476 isolates. The results indicated high levels of genotypic variability, which is consistent with a genetically diverse initial inoculum. Genetic identities among populations representing the three spatial scales were >98%. Tests for differentiation among populations due to population subdivision revealed that on average 97.5% of the genetic variability occurred within populations with a correspondingly high migration rate of 16 to 23 individuals per generation. We observed little evidence of linkage disequilibrium, on average, only 4.6% of locus pairs were in disequilibrium. Our results indicate that Kansas populations of M. graminicola are characterized by regular recombination, are genetically diverse, and appear to be homogenous across different spatial scales. These populations are probably components of a larger pathogen pool that is distributed at least across much of Kansas and probably the central Great Plains. Because of the frequent recombination, the risk of adaptation of Kansas populations of M. graminicola to fungicide treatments or resistance genes is high and could be dispersed very quickly, whether these new pathogenic traits occur locally through mutation or by migration from other areas.

As bananas devem ser colhidas em seu estado verde (pré-climatérico) para disponibilizar tempo suficiente para transporte e comercialização. Este tempo é conhecido como vida-verde, determinado pelo número de dias existentes entre a colheita e o início do amadurecimento natural do fruto. As Sigatokas, em especial a Sigatoka Negra, são atualmente os problemas mais sérios do cultivo da bananeira. Embora estas doenças ataquem as folhas, os principais danos causados podem ser atribuídos à perda de qualidade e, consequentemente, de valor comercial dos frutos. Este trabalhou investigou os efeitos causados por estas doenças sobre a vida-verde e outros parâmetros de qualidade; tais como, coloração da polpa, sensibilidade ao apodrecimento pós-colheita, tamanho e peso, perfil respiratório e produção diária de etileno. Além disso, foi avaliada, em caráter preliminar, a evolução diária de alguns desses e outros parâmetros durante o processo de amadurecimento induzido do fruto, simulando a qualidade do fruto durante a comercialização no mercado varejista. Os resultados indicam que a vida verde é fortemente reduzida por ambas doenças (cerca de 50%) e não apresenta nível crítico de infestação. A intensidade respiratória e a produção de etileno foram aumentados e desordenados para os frutos oriundos de bananais infestados pelas doenças, especialmente S. Negra. O peso é reduzido em 40% pela infestação de S. Negra. A S. Amarela parece não influenciar a sensibilidade dos frutos ao apodrecimento pós-colheita. A Sigatoka Amarela provoca alteração na coloração da polpa, semelhante a perda de intensidade de cor. / Banana fruits are harvested at a green mature stage (pre-climacteric) in order to allow sufficient time for transport and marketing. This period is known as greenlife, and it is determined by the number of days between harvest and the initiation of the natural ripening process. Sigatoka Disease and, specially, Black Leaf Streak Disease are the main seriously problems in banana production, and it is also called by Yellow Sigatoka and Black Sigatoka, respectively. Although it is foliar diseases, the main damage is related to reduced quality and loss of market value. This study has investigated the effects of these diseases on the greenlife and other quality parameters; such as, pulp color, sensitivity to post-harvest rot, size and weight, respiration profile and ethylene daily production. Besides, it was preliminary evaluated the daily evolution of some of those and other parameters during the induced ripening process, as simulating fruit quality over retail market. Results indicate that greenllife is strongly reduced (about 50%) and it had no critical level of disease infestation. Respiratory intensity and ethylene production were increased and disorderly, for fruits from infested plots, specially by Black Sigatoka. Weight is 40 % reduced by Black Sigatoka. Yellow Sigatoka appear to have no influence on the sensitivity os post-harvest rot. However, Yellow Sigatoka caused an altered pulp color, similar to less intensity.

Made available in DSpace on 2015-03-26T13:58:40Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1058323 bytes, checksum: 6b28eb55ea2237955a72ef93867127be (MD5) Previous issue date: 2013-12-17 / Black Sigatoka, caused by Mycosphaerella fijiensis, is one of the most detrimental diseases for banana plantations in Brazil and worldwide. Although its occurrence in the state of Minas Gerais (MG) was first reported in 2004, the fears of economic disaster to banana growers never materialized along the past ten years. There is a clear paradox in this case, for a disease known to be devastating to this crop. Here this paradox is examined in detail and a narrative of the events that preceded and followed the first reports of the disease in MG. The initiatives taken by federal and state agencies to control the spread of the disease are discussed as well as the reasons and body of legislation behind the decisions that were taken along the years. A visit was made to the Zona da Mata region in Minas Gerais in areas regarded as being "positive" for the occurrence of the disease was performed. Interviews with banana growers in this region as well as extension workers, scientists and other professionals involved with the issue since 2004 were made. In addition, we analyzed data from surveys carried out by different groups at different occasions after the supposed outbreak in 2004. Evidence shows that the disease did not progress to new areas, and in 2007 it was not found in the areas in municipalities that are still strangely considered as "positive for the occurrence of disease". All reports from such studies (published or not) mention the contradiction between the predictions of a disastrous expansion of the disease and the observed continuation of the status quo for banana plantations for all areas in MG. Although awkward, the more acceptable hypothesis is that mistakes in identification of the pathogen have been originally committed. The final elucidation of the paradox is discussed and suggestions for modifying the federal and state legislation and regulations in order to repair the present situation and prevent the emergence of similar situations in the future are presented. / A Sigatoka-negra, causada por Mycosphaerella fijiensis, é uma das doenças mais prejudiciais à cultura da bananeira no Brasil e no mundo. Embora sua ocorrência tenha sido relatada pela primeira vez em 2004 no Estado de Minas Gerais, o temido desastre econômico esperado para os bananicultores do estado, passados dez anos, não se confirmou. Há um claro paradoxo neste caso, para uma doença sabidamente devastadora para a cultura. Realizou-se aqui um estudo deste paradoxo, pretendendo-se construir uma narrativa dos eventos que antecederam e se seguiram a esta ocorrência em MG, avaliando-se como as iniciativas para o controle da disseminação da doença foram conduzidas pelos órgãos de defesa agropecuária federal e estadual e como foram embasadas suas decisões, bem como discutindo o impasse gerado pelas imperfeições da legislação em vigor a cada tempo. Uma visita à região da Zona da Mata mineira em , em que foram feitas entrevistas com bananicultores desta região, assim como técnicos e profissionais envolvidos com o tema e que participaram de forma efetiva dos trabalhos conduzidos a partir de 2004. Além disso, analisaram-se os dados de levantamentos e monitoramentos realizados no período subsequente a 2004, mostrando que a doença não avançou para novas áreas, e que a partir de 2007 ela não foi encontrada nas áreas que ainda Todos os estudos posteriores a 2004 (publicados ou não) citam a contradição entre as previsões sobre um avanço do fungo e a observada continuação do status quo para a bananicultura mineira. A hipótese mais aceitável, embora embaraçosa, é a de que equívocos na identificação do patógeno tenham sido cometidos. A resolução final da situação paradoxal que se vive nesta questão em Minas Gerais é discutida e sugestões para a modificação da legislação e normas federais e estaduais de modo a corrigir este problema e problemas futuros são apresentadas.

As bananas devem ser colhidas em seu estado verde (pré-climatérico) para disponibilizar tempo suficiente para transporte e comercialização. Este tempo é conhecido como vida-verde, determinado pelo número de dias existentes entre a colheita e o início do amadurecimento natural do fruto. As Sigatokas, em especial a Sigatoka Negra, são atualmente os problemas mais sérios do cultivo da bananeira. Embora estas doenças ataquem as folhas, os principais danos causados podem ser atribuídos à perda de qualidade e, consequentemente, de valor comercial dos frutos. Este trabalhou investigou os efeitos causados por estas doenças sobre a vida-verde e outros parâmetros de qualidade; tais como, coloração da polpa, sensibilidade ao apodrecimento pós-colheita, tamanho e peso, perfil respiratório e produção diária de etileno. Além disso, foi avaliada, em caráter preliminar, a evolução diária de alguns desses e outros parâmetros durante o processo de amadurecimento induzido do fruto, simulando a qualidade do fruto durante a comercialização no mercado varejista. Os resultados indicam que a vida verde é fortemente reduzida por ambas doenças (cerca de 50%) e não apresenta nível crítico de infestação. A intensidade respiratória e a produção de etileno foram aumentados e desordenados para os frutos oriundos de bananais infestados pelas doenças, especialmente S. Negra. O peso é reduzido em 40% pela infestação de S. Negra. A S. Amarela parece não influenciar a sensibilidade dos frutos ao apodrecimento pós-colheita. A Sigatoka Amarela provoca alteração na coloração da polpa, semelhante a perda de intensidade de cor. / Banana fruits are harvested at a green mature stage (pre-climacteric) in order to allow sufficient time for transport and marketing. This period is known as greenlife, and it is determined by the number of days between harvest and the initiation of the natural ripening process. Sigatoka Disease and, specially, Black Leaf Streak Disease are the main seriously problems in banana production, and it is also called by Yellow Sigatoka and Black Sigatoka, respectively. Although it is foliar diseases, the main damage is related to reduced quality and loss of market value. This study has investigated the effects of these diseases on the greenlife and other quality parameters; such as, pulp color, sensitivity to post-harvest rot, size and weight, respiration profile and ethylene daily production. Besides, it was preliminary evaluated the daily evolution of some of those and other parameters during the induced ripening process, as simulating fruit quality over retail market. Results indicate that greenllife is strongly reduced (about 50%) and it had no critical level of disease infestation. Respiratory intensity and ethylene production were increased and disorderly, for fruits from infested plots, specially by Black Sigatoka. Weight is 40 % reduced by Black Sigatoka. Yellow Sigatoka appear to have no influence on the sensitivity os post-harvest rot. However, Yellow Sigatoka caused an altered pulp color, similar to less intensity.

Studies presented in this thesis, highlight the complexity and importance of Mycosphaerella leaf disease (MLD) on Eucalyptus spp., especially in South Africa. In Chapter I, a review of the literature dealing with Mycosphaerella and MLD of Eucalyptus spp. is presented. It is clear from this review that the disease is prevalent in most countries where Eucalyptus spp. are commercially grown, including Australia where they are native. The number of Mycosphaerella species known from Eucalyptus spp. is increasing and this suggests that their economic effect on commercial Eucalyptus forestry, will probably Increase. It will thus become important to effectively identifY species responsible for MLD. To do this, the existing complex taxonomy of this group of fungi, will undoubtedly prove to be an obstacle. However, DNA based identification methods are proving useful in identifying species and delimiting lineages within Mycosphaerella. Future commercial propagation of Eucalyptus spp. will need to seriously consider the use of hybrids resistant to infection by Mycosphaerella spp. Furthermore, there will be a serious need for effective quarantine measures to prevent the introduction of new, perhaps more pathogenic, Mycosphaerella spp. into areas where they do not already occur. Three species of Mycosphaerella, M. molleriana, M. M. nubilosa and M. juvenis have traditionally been regarded as the most important Mycosphaerella spp. in South Africa. At various times, each species has been considered to be the only pathogen causing MLD in the country. Results from Chapter 2 and Chapter 3 have shown that M. nubilosa is the main pathogen responsible for MLD, especially, on E. nitens in the KwaZulu-Natal province of South Africa. This is interesting as M. molleriana, which was originally thought to be the only species in South Africa, was not isolated. Moreover, the susceptibility of E. nitens to M. nubilosa appears to be high, resulting in severe defoliation. Considering that E. nitens is a popular species grown at higher altitudes of South Africa, the recognition of M. nubilosa is important. This fungus is well recognized in Australia as an important pathogen and comparisons of data from that country will be useful in the future. Several Mycosphaerella spp. have, in the past been found to occur within single stands of commercial Eucalyptus spp. As part of the research presented in Chapter 3, surveys conducted in South Africa showed that there are seven species of Mycosphaerella occurring in plantations. These include: M. ellipsoidea, M. irregulariramosa, M. juvenis, M. lateralis, M. marksii, M. nubilosa and one newly described species M. fori. All of these species, apart from M. fori, were previously known to occur in South Africa. It is interesting that M. juvenis, previously thought to be one of the main species causing MLD, was found only to occur in a low numbers. This suggests that species causing epidemics may change over time. The identification of M. fori from a previously well surveyed area was unexpected. This new species was dominant in Tzaneen and future surveys will be conducted to determine its distribution and host range within South Afiica. The identification of a new species also highlights the need for additional surveys in South Africa to identify new species and to recognize possible new introductions of exotic Mycosphaerella spp. The presence of M. ellipsoidea, M. irregulariramosa, M. lateralis and M. marksii in this survey was not unusual, as they were previously known in South Africa. However, they were found only to occur at low levels and, as such, do not seem to contribute significantly to outbreaks of MLD.Various taxonomic and DNA-based methods have been used for the identification of Mycosphaerella spp. However, some taxonomic characters are of little value at the species level. In Chapter 4, RFLP's were considered as an option to differentiate between species of Mycosphaerella on Eucalyptus. Results of this study showed that the restriction enzyme HaeIII may be used for RFLP identification of Mycosphaerella spp. From a total of twenty-one Mycosphaerella spp. tested, RFLP digestion with HaeIII could resolve six of these species to species level. However, other species formed groups that had similar restriction profiles. They could be further separated based on ascospore germination patterns. This study forms a foundation for future studies in which other enzymes may be used together with HaeIIi to elucidate groups of species. It is suggested though, that this technique be combined with existing methods such as ascospore germination patterns and anamorph associations to identify species of Mycosphaerella occurring on Eucalyptus spp. with confidence. This should negate the use of expensive sequencing techniques, which are currently necessary. In virtually every country where Eucalyptus is grown commercially, MLD is prevalent. However, the specific Mycosphaerella spp. in countries are generally not the same. In Chapter 5, I used DNA sequence data from the ITS region of the rDNA operon as well as morphological data to identify M. heimii from Brazil and Hawaii, U.S.A. This represents the first report of the species from these countries. M heimii was previously thought to occur only in Madagascar and Indonesia, where it is recognized as a primary pathogen of several Eucalyptus spp, including E. urophylla. This is one of the main Eucalyptusspp. in Brazil. It has thus been suggested that this species may have been introduced into these countries via infected seed lots. This highlights the need for effective quarantine measures within these and other South American countries to inhibit the further spread of this pathogen through South America. Copyright / Dissertation (MSc)--University of Pretoria, 2011. / Microbiology and Plant Pathology / Unrestricted