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Grapevine rhizosphere bacteria : influence of diversity and function on two root diseases : a thesis submitted in fulfilment of the requirements for the degree of Master of Science at Lincoln University /Dore, Dalin Shelley. January 2009 (has links)
Thesis (M. Sc.) -- Lincoln University, 2009. / Also available via the World Wide Web.
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Antimicrobial activity of essentail oils against Fusarium oxysporum isolates and their biofilms.Manganyi, Madira Coutlyne. January 2013 (has links)
M. Tech. Pharmaceutical Sciences Tshwane University of Technology 2013. / Aims of the present study was to evaluate the inhibitory activities of essential oils against Fusarium isolates and their corresponding biofilms. In this study, the chemical compositions of the oils were established using gas chromatography with both mass spectrometric and flame ionization detection, for identification and quantification, respectively.
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The infection process of Fusarium oxysporum f. sp. vasinfectum in Australian cotton and associated cotton defence mechanismsHall, Christina Rachael January 2007 (has links)
Fusarium oxysporum f. sp. vasinfectum (Fov) was first identified in Australia in 1993, and has since become one of the most significant threats to the country’s thriving cotton industry. The interaction between a unique Australian biotype of Fov and cotton hosts with varying susceptibilities to Fusarium wilt was studied. This research described the infection process and associated host defence mechanisms of two commercial cotton varieties after inoculation with Fov, and quantified their subsequent accumulation of antimicrobial terpenoids. / A rapid, reliable glasshouse bioassay that correlated with field resistance was developed for the study of Fusarium wilt of cotton. Detailed observations of the infection process obtained through light microscopy were used to formulate the disease cycle of Australian Fusarium wilt cotton. Using pathogen growth assays, varietal differences in root exudates and vascular tissues in the cotton hosts were documented. Root diffusate from the most susceptible cotton variety to Fusarium wilt, Siokra 1-4, contained a lipophilic compound that promoted the germination of Fov microconidia. On the other hand, a lipophilic compound present in diffusate from the least susceptible variety, Sicot 189, inhibited the growth of Fov germ tubes. / A bioassay using inoculated whole plants showed that Fov colonisation of the vascular tissues of Sicot 189 was restricted after 3 days. The basis for this inhibition was investigated further using light and transmission electron microscopy. Infection induced the reorganisation of contact cells in host vascular tissue, including an increase in cytoplasmic content and the partitioning of vacuoles, which was concurrent with the accumulation of materials in adjacent vessel lumens, via pits. Histochemical analysis indicated these globular materials secreted into the vessels were terpenoids. These structural and terpenoid responses in Siokra 1-4 and Sicot 189 were similar, however, they were more intense and rapid in the latter, less susceptible variety. The responses in Sicot 189 also corresponded to the time period that pathogen inhibition was observed. Thus, a correlation was demonstrated between the rapid and intense induction of both structural and biochemical responses with decreased susceptibility to Fusarium wilt. Detailed HPLC analysis of vascular tissues confirmed that terpenoids accumulated more rapidly and at higher concentrations in the less susceptible cotton variety. These findings provided strong evidence for the involvement of antimicrobial terpenoids in the determination of Fusarium wilt susceptibility of Australian cotton varieties. / This work represents the most complete survey to date of the interaction of Australian biotypes of Fov with cotton. These insights can contribute to future cotton breeding efforts and cultural management of Fusarium wilt in the field. Thus, each part of this study has advanced complementary facets of our understanding of Fov, and has provided a framework from which future studies on phytoalexins and other putative cotton defences can be studied.
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Seed-borne fungi of the afromontane tree species Podocarpus falcatus and Prunus africana in Ethiopia /Gure, Abdella, January 2004 (has links) (PDF)
Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniversitet, 2004. / Härtill 4 uppsatser.
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Abiotic and biotic factors in the nutrient solution and filter skin (Schmutzdecke) of slow filters integrated to closed hydoponic greenhouse : potential predictors for assessment of efficacy /Furtner, Bernhard, January 2006 (has links) (PDF)
Licentiatavhandling (sammanfattning) Alnarp : Sveriges lantbruksuniversitet, 2006. / Härtill 2 uppsatser.
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Molecular biological studies of the Fusarium wilt pathogen of banana in South AfricaVisser, Marinda. January 2003 (has links)
Thesis (Ph. D.)(Genetics)--University of Pretoria, 2003. / Title from opening screen (viewed 8th April, 2005). Includes summary. Includes bibliographical references.
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Responses and relationships among Fusarium species, sweet corn, and western spotted cucumber beetles /Miller, Nathan L. January 1900 (has links)
Thesis (Ph. D.)--Oregon State University, 2007. / Printout. Includes bibliographical references. Also available on the World Wide Web.
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Micorrização e resistência a Fusarium oxysporum Sch. f. sp. herbemontis em genótipo de porta-enxerto de videiraDalla Costa, Murilo 25 October 2012 (has links)
Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias, Programa de Pós-graduação em Recursos Genéticos Vegetais, Florianópolis, 2010 / Made available in DSpace on 2012-10-25T06:57:06Z (GMT). No. of bitstreams: 1
276368.pdf: 19499211 bytes, checksum: a68479fe79440173224ed0cfd8bac176 (MD5) / O declínio e morte de videiras, problema fitossanitário que limita a vitivinicultura no estado de Santa Catarina, tem como um dos agentes causais o fungo do solo Fusarium oxysporum f. sp. herbemontis. Até o momento, o controle da murcha vascular causada pelo patógeno é feito com uso de porta-enxertos resistentes. A inoculação de fungos micorrízicos arbusculares na fase de aclimatização de videiras micropropagadas in vitro pode acelerar a produção de mudas de alta qualidade; essa biotecnologia pode também reduzir a incidência de Fusarium spp., podendo melhorar a expressão do potencial genético de porta-enxertos, até mesmo daqueles suscetíveis ao patógeno. Os mecanismos de resistência de plantas micorrizadas a patógenos radiculares ainda estão pouco esclarecidos, especialmente no que se refere ao papel indutor da simbiose na expressão de genes de defesa da planta. O trabalho tem como objetivo avaliar, em genótipo de porta-enxerto suscetível a fusariose, o papel da formação de micorriza na expressão de proteínas radiculares e na indução de resistência localizada contra F. oxysporum f. sp. herbemontis. Mudas micropropagadas de videira da cultivar SO4 foram aclimatizadas e metade delas foram inoculadas com o fungo micorrízico Glomus intraradices. Após 75 dias, as raízes das plantas foram mergulhadas em suspensão de conídios de Fusarium spp. ou água estéril. Para realizarem-se avaliação dos níveis de atividade hidrolítica das enzimas quitinases e -1,3-glucanases e para eletroforese bidimensional de proteínas, amostras radiculares foram coletadas aos quatro e aos 14 dias após a inoculação do patógeno, respectivamente. A avaliação de sintomas de infecção por Fusarium spp. foi realizada aos 90 dias após inoculação do patógeno. A expressão de quitinases acima dos níveis basais foi induzida nas raízes dos tratamentos com inoculação do fungo micorrízico e/ou patógeno. A atividade de -1,3-glucanases foi maior somente no tratamento com inoculação de G. intraradices e do patógeno. Os simbiontes mutualístico e parasítico induziram 11 e duas proteínas, respectivamente. A formação de micorrizas e a inoculação de Fusarium spp. promoveram mudanças no nível de expressão de 13 proteínas do sistema radicular de videiras. Videiras inoculadas com G. intraradices apresentaram diminuição nos sintomas de infecção por Fusarium spp., sugerindo que a simbiose mutualística promoveu a indução de quitinases e -1,3-glucanases com ação específica na supressão do patógeno, bem como a expressão diferenciada de proteínas relacionadas com indução de resistência e com efeito bioprotetor contra o patógeno vascular.
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Zhodnocení odrůdové odolnosti vybraného sortimentu zeleniny vůči houbovým patogenům / Evaluation of cultivars tolerance of chosen vegetable assortment to fungal diseasesMaláková, Dana January 2016 (has links)
The aim of this Diploma thesis was to assess the cultivar tolerance of a chosen assortment of butterhead lettuce, leaf lettuce, iceberg lettuce and cabbage to fungal pathogens (Bremia lactucae, Fusarium oxysporum f. sp. conglutinans).
The experiment was conducted in the laboratory conditions of the gardening department FAPPZ of the Czech University of Agriculture in growth chambers. The lettuce experiments were done in given conditions with the temperatures of 18 - 20 °C under the regime 12 hrs. of light and 12 hrs. of darkness. The cabbage experiments were conducted in given conditions under the regime 12 hrs. of light and 12 hrs. of darkness with the temperatures of 14 °C during the day and 12 °C in the night. The lettuce plants were planted in dishes on fine sand. All experiments had infected and control variants. After emergence, the experimental plants were inoculated with variants of the selected pathogen. The plants were observed in 2 - 3 day intervals throughout the whole experiment. The experiment was assessed using the modified standard method according to Pawelec et al. (2006). A modified method with a percentage scale was used to assess the lettuce experiments. Cabbage experiments were evaluated with a scale of points ranging from 0 to 9 according to the percentage of infection on the plants. The results of the methodology were determined using the program Statistica 12.
In the experiments evaluating the variety tolerance of a chosen assortment leaf lettuce and iceberg lettuce to the pathogen Bremia lactucae Bl:31, a statistically significant difference in the sensitivity to this pathogen was established. The results show that the most resistant varieties are Tarzan, Stamir, Adinal a Verala. The greatest sensitivity to the pathogen Bl:31 has a variety "Dětenická Atrakce" then Traper and Nikolaj. Effect of seed treatment with hot water (HWT) to suppress pathogen B. lactucae was statistically significant in the varieties "Dětenická Atrakce" (10% decrease) and Dubáček (7% decrease) compared with untreated infectious variant with HWT. In the sensitivity evaluation of varieties and lines of white cabbage was a statistically significant difference in infecting of pathogen Fusarium oxysporum f. Sp. conglutinans breed 1. The most significantly susceptible to the pathogen Foc was variety Pourovo late-season (degree of assault after inoculation was 6.52 points).
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Análise da diversidade genética por marcadores RAPD e SSR em Fusarium oxysporum f. sp. cubense no Estado de Santa CatarinaSilva, Cristiane Maria da 24 October 2012 (has links)
Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias, Programa de Pós-graduação em Recursos Genéticos Vegetais, Florianópolis, 2009 / Made available in DSpace on 2012-10-24T07:27:40Z (GMT). No. of bitstreams: 1
274971.pdf: 2846578 bytes, checksum: f745a914e07ddeda6a34cc83417453f8 (MD5) / O Mal-do-Panamá causado por Fusarium oxysporum f. sp. cubense (FOC) é um dos principais problemas fitossanitários da bananicultura. Para esta doença, o uso da resistência genética é o método de controle recomendável. Porém, sua eficiência depende tanto de genes de resistência disponíveis como da presença de patótipos do patógeno. Assim este estudo teve como objetivo caracterizar a diversidade genética de isolados de FOC por meio de descritores morfológicos e marcadores moleculares (RAPD, SSR). Para tanto, foram avaliados 66 isolados coletados em regiões produtoras de Santa Catarina. Os resultados de patogenicidade revelaram que 100% dos isolados foram patogênicos à bananeira da cultivar Enxerto. Quanto às características morfológicas dos isolados não se observou diferenças significativas com relação à taxa de crescimento das colônias, que variaram de 4,4 a 6,6 mm.dia-1. A coloração das colônias sobre meio de cultura BDA variou de branco, salmão e roxo. Os resultados utilizando marcadores moleculares RAPD apresentaram uma variabilidade considerável entre os isolados de FOC, com estimativas de similaridade que variaram de 35 a 98%. Baseado nos 10 marcadores selecionados de RAPD, os 66 isolados foram agrupados em cinco grupos distintos, sendo que o número de indivíduos provenientes das regiões norte e sul do Estado foi igualmente distribuído no primeiro grupo, onde 58 indivíduos foram agrupados. Nos outros quatro grupos formados teve-se somente isolados provenientes do norte do Estado, os quais apresentaram uma maior distância genética quando comparados ao grupo um. A técnica de marcador molecular SSR separou os isolados em três grupos distintos. O primeiro grupo foi constituído de 59 indivíduos provenientes dos diversos municípios onde as coletas foram feitas. O segundo grupo, composto por dois isolados (CO16, JS23), caracterizou-se por apresentar alelo nulo para o marcador MB11. Já o terceiro grupo, formado por quatro isolados (JS26, SI53, SI54, SI55, SI56), apresentou um alelo extra no marcador MB02. No estudo de compatibilidade vegetativa não foi possível observar o pareamento entre os quatro isolados testados não havendo, portanto compatibilidade vegetativa entre os mesmos. Não houve associação dos agrupamentos RAPD e SSR com origens geográficas e características morfológicas da colônia de FOC, visto que os isolados foram distribuídos indistintamente nos grupos.
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