Orientador: Marcelo Agenor Pavan / Coorientador: Denise Nozaki / Banca: Rumy Goto / Banca: Romulo Fujito Kobori / Resumo: A murcha de fusário, causada pelo fungo de solo Fusarium oxysporum f.sp. lactucae é uma das doenças mais severas que ataca m a cultura da alface em todo o mundo. Em 2011, foram encontrados em uma plantação de alface n os município s de Capão Bonito e Campin as n o estado de São Paulo, sintomas característicos do ataque do patógeno. Plantas sintomáticas foram coletadas para identificação do patógeno. O s exame s em microscóp io óptico revel aram a presença de macroconídios falcados de coloração hialina, microconídi os hialinos unicelulares e testes de patogenicidade revelaram a presença de Fusarium oxysporum f.sp. lactucae . Efetuou - se o re - isolamento do patógeno, completa ndo - se assim o Postulado de Koch . No total, for am encontrados 4 isolados patogê nicos atacando pla ntas de alface. A partir do s isolados identificados , fo ram caracterizada s as variações patogênicas através de diferenciadoras de raça. Para esta finalidade foram utilizadas Patriot ( suscetível às raças 1, 2 e 3 ), Costa Rica ( resistente à raça 1 ; suscetível às raças 2 e 3 ), Summer Green ( suscetível às raças 1 e 3 ; resistente à raça 2 ) e Banchu Red Fire ( suscetível às raças 1 e 3, resistente à raça 2 ) . Os resultados obtidos identificaram a ocorrência da raça 3 de Folac. Este é o primeiro relato de ocorrência desta raça no Brasil . A partir do isolado selecionado como sendo o mais agressivo , e caracterizado como pertencente a raça 3 , r ealizou - se a triagem de genótipos de alface, afim de identificar fontes de resistência para uso em programas de melhoramento . No total de 63 genótipos testados apenas Onondaga, Itha ca, Sudenvil e JP - 11 apresentara m - se como resistente a raça 3 de Fusarium oxysporum f.sp. lactucae / Abstract: The fusarium wilt, caused b y the soil fungus Fusarium oxysporum f.sp. soil lactucae is one of the most severe diseases that attack lettuce crop worldwide. In 2011, were found in a pla nting lettuce in Capão Bonito and Campinas in São Paulo, symptoms characteristic of this pathogen. S ymptomatic plants were collected for pathogen identification. The optical microscope examinations revealed the presence of hyaline staining falcate macroconidia, microconidia unicellular hyaline and pathogenicity tests revealed the presence of Fusarium oxy sporum f.sp. lactucae. We performed the re - isolation of the pathogen, there by supplementing the Koch's postulate. For this purpose were used: Patriot(susceptible to races 1, 2 and 3), Costa Rica (susceptible to races 2 and 3, resistant to race 1); Summer Green (susceptible to races 1 and 3; resistant to race 2) and Banchu Red Fire (susceptible to races 1 and 3, resistant to race 2). The results show the occurrence of race 3 of Folac. This is the first report of the case in Brazil. From the isolated select ed as being the 3 most aggressive, and characterized as belonging to race 3 was held screening of lettuce genotypes in order to identify sources of resistance for use in breeding programs. From of 63 genotypes tested only Onondaga, Ithaca, Sudenvil and JP - 11 were identified as resistant to race 3 of Fusarium oxysporum f.sp. lactucae / Mestre

Proefschrift Universiteit van Amsterdam. / Auteursnaam op omslag: Eugène Roebroeck. Met lit. opg. - Met samenvatting in het Nederlands.

Made available in DSpace on 2014-06-12T15:03:57Z (GMT). No. of bitstreams: 2 arquivo4377_1.pdf: 7022466 bytes, checksum: ddcd0ae8a9c48ea3d7bc2290ffa19a0c (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2000 / Quinze isolados de Fusarium oxysporum f.sp. passiflorae provenientes do nordeste do Brasil foram analisados quanto a sua variabilidade genética utilizando a técnica de RAPD (Random Amplified Polymorphic DNA) e em termos de características morfofisiológicas. Os isolados foram obtidos da Micoteca-URM do Departamento de Micologia/UFPE, Recife-PE. Na primeira etapa deste trabalho, foram observadas as características morfológicas (coloração e aspecto da colônia) e fisiológicas (crescimento e taxa de crescimento micelial dos isolados), utilizando-se dois meios de cultura, o BDA e o CZA. As características micromorfológicas também foram observadas, após microcultivos, utilizando o meio BDA. Os resultados obtidos, indicaram que houve maior variação no crescimento e também na expressão da coloração micelial dos isolados colonizados em meio BDA. As amostras apresentaram uma variação significativa em relação as taxas de crescimento entre os meios CZA e BDA. Para a investigação do polimorfismo de DNA dos isolados utilizando-se a técnica de RAPD, foram testados 57 primers dos quais quatro foram selecionados considerando-se a geração de bandas mais fortes, mais definidas e em maior número. Os primers selecionados geraram um total de 448 bandas, permitindo a construção de uma matriz de similaridade. Observou-se elevado polimorfismo genético, pois pelo menos uma banda não estava presente em todas as amostras não havendo presença de bandas monomórficas. O coeficiente médio de similaridade obtido para todas as amostras foi de 0.62 (62%). O dendrograma gerado a partir dos dados da matriz revelou uma alta variabilidade genética entre os isolados, pertencentes a mesma formae specialis. Aparentemente, não existe correlação entre a taxa de crescimento micelial e agrupamento dos isolados no dendrograma

Fusarium oxysporum Schlecht. is a cosmopolitan species complex that consists of both pathogenic and non-pathogenic members. The pathogenic members are subdivided into formae speciales, based on virulence to specific host species. More than 150 formae speciales have been described, of which F. oxysporum f.sp. cubense (E.F.Smith) Snyder and Hansen (Foc), causal agent of Fusarium wilt of banana, is regarded as one of the economically most important and destructive. According to phenotypic and genotypic markers, Foc has been classified into three races and 24 vegetative compatibility groups, and can be divided into a number of clonal lineages that roughly correspond with VCG groupings. In this thesis, we investigated the evolutionary relationships among VCGs using multi-gene sequencing and MAT genotyping. A PCR-RFLP fingerprint discriminating the Foc lineages and a PCR primer that identified Foc ‘subtropical’ race 4 isolates, was developed. Nine microsatellite markers (SSRs) were applied to a global population of Foc in order to investigate diversity not always detectable using sequencing data. Phylogenetic analysis of isolates representing Foc, various other formae speciales of F. oxysporum and non-pathogenic F. oxysporum of the genes encoding the translation elongation factor-1á (TEF), the mitochondrial small subunit (MtSSU), ribosomal RNA (rRNA), the repeated region encoded on the mitochondrion (MtR) and the intergenic spacer (IGS) gene regions separated these isolates into four clades, two of which included Foc. Within these two clades, Foc separated into six lineages that broadly corresponded to VCGs, while the non-pathogenic isolates of F. oxysporum grouped together in only one of the two clades, with an unknown Foc VCG isolate. The mating type of all isolates was determined and crosses were attempted between isolates harbouring MAT-1 and MAT-2 genes, without success. Cultural, morphological and pathogenic variation among isolates of Foc was unable to identify lineages as species. The separation of Foc isolates into two clades suggested that the banana pathogen evolved during two unrelated events. Factors such as horizontal gene transfer, however, might also have played a part in the pathogen’s evolution, as was evident from the divergent placement of some VCGs and lineages within the phylogenetic trees constructed. The inclusion of other formae speciales of F. oxysporum and non-pathogenic F. oxysporum isolates illustrated the great diversity that exists within the F. oxysporum complex. The inclusion of the Foc isolate of an unknown VCG suggests that the genetic diversity of Foc might be far greater than what is known and what was revealed in this study. The opposite mating types found in the respective lineages indicate a sexual origin for the Fusarium wilt fungus that could account for its polyphyletic nature. Within South Africa, Foc ‘subtropical’ race 4 is regarded the most important constrain to banana production. Conventional control practices for Fusarium wilt of banana are ineffective, and disease management relies heavily on the use of clean planting material and the early detection and isolation of the pathogen, in order to restrict spread to unaffected areas. Identification of Foc typically involves vegetative compatibility assays and pathogenicity testing using a set of differential host cultivars. The development of a PCR-based method for the rapid and accurate identification of Foc ‘subtropical’ race 4 will, therefore, be of great importance. The lack of morphological variation between lineages of Foc, and between pathogenic and non-pathogenic members, as well as the unreliability in race identification in Foc, makes the use of molecular tools a viable alternative. Following DNA isolation, PCR and sequencing of the MtR, the DNA sequence data revealed an 8-bp insertion that was subsequently targeted for the design of a Foc ‘subtropical’ race 4-specific primer. Isolates were positively identified as Foc ‘subtropical’ race 4 with the amplification of an 800-pb fragment. The development of the Foc ‘subtropical’ race 4 primer will aid in rapid and accurate detection of the Fusarium wilt pathogen of banana. The population structure defined according to SSR data of a global population of 239 Foc isolates resembled the structure defined according to multi-gene phylogeny, with some exceptions. Measures of gene and genotypic diversity unequivocally supported the opinion that Asia is the centre of origin of Foc. The presence of unique genotypes in all geographically-defined Foc populations could potentially indicate their evolution outside the centre of origin, although this is highly unlikely. The absence of certain genotypes from the Asian population was either due to insufficient and selective sampling, or it demonstrated the effects of clonal selection in combination with adaptation to the forces of geographic isolation and environmental changes over time. The worldwide collection of Foc mostly consisted of six over represented genotypes, thereby providing support for a clonal genetic structure. It was, however, not possible to reject the hypothesis of a recombining population for the populations representing isolates of Lineage V. The implication of recombination within some Foc lineages may be due to unobserved sexual reproduction in nature or the historical association with a sexual ancestor. When one considers diversity within and among genotypes, a specific genotype was mostly associated with only one or two Foc VCGs, therefore indicating that vegetative compatibility determination, in combination with phylogenetic analyses, is a powerful tool for characterizing isolates causing Fusarium wilt of banana. Results from this study, in combination with the multi-gene phylogeny, clearly indicated the presence of unrelated lineages that most probably represent cryptic species. Copyright 2008, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. Please cite as follows: Fourie, G 2008, Evolutionary biology of Fusarium oxysporum f.s.p. cubense, MSc dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-11192008-094622/> E1216/gm / Dissertation (MSc)--University of Pretoria, 2008. / Microbiology and Plant Pathology / unrestricted

No description available.

Fusarium oxysporum grown on natural media was believed not to produce mycotoxins of the trichothecene family. Using a defined chemical medium toxin production was investigated for and it was found that trichothecenes were produced. A yeast bioassay using Kluyveromyces fragilis, an organiam sensitive to such trichothecenes as T-2 toxin and verrucarin, was used for detection of toxin in culture filtrates. Detectable levels of toxin (0.2 $ mu$g in litre of culture) were seen by day 4 and peaked around day 9 corresponding to maximum growth (measured by mycelial mass). After this time fluctuations in the level of toxin and growth became evident, suggesting a breakdown of the toxins by the organism for a carbon source. Search for an enzyme or enzyme system, capable of degrading T-2 toxin in snail gut enzyme digested F. oxysporum, was attempted using the esterase substrate para-nitrophenol acetate. Esterase activity was detected in all fractions including culture filtrate, soluble protein fraction and insoluble protein fraction, as well as solubilized insoluble proteins (digested by contents of the crude extract). The soluble protein fraction exhibited the highest level of activity. Cells digested with the detergent Lubrol followed by precipitation of the solubilized proteins with ammonium sulphate revealed the presence of an active component(s) in the high molecular weight portion of the soluble cell fraction collected at 50 and 75% saturation. Further purification by DEAE-sepharose failed to produce an active component.

Proefschrift Universiteit van Amsterdam. / Met lit. opg. - Met samenvatting in het Nederlands.

Made available in DSpace on 2014-12-02T11:16:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-09-05Bitstream added on 2014-12-02T11:21:37Z : No. of bitstreams: 1 000800061.pdf: 1547565 bytes, checksum: 2df2d2d64d204de432cc47eb081a5653 (MD5) / A murcha de fusário, causada pelo fungo de solo Fusarium oxysporum f.sp. lactucae é uma das doenças mais severas que ataca m a cultura da alface em todo o mundo. Em 2011, foram encontrados em uma plantação de alface n os município s de Capão Bonito e Campin as n o estado de São Paulo, sintomas característicos do ataque do patógeno. Plantas sintomáticas foram coletadas para identificação do patógeno. O s exame s em microscóp io óptico revel aram a presença de macroconídios falcados de coloração hialina, microconídi os hialinos unicelulares e testes de patogenicidade revelaram a presença de Fusarium oxysporum f.sp. lactucae . Efetuou - se o re - isolamento do patógeno, completa ndo - se assim o Postulado de Koch . No total, for am encontrados 4 isolados patogê nicos atacando pla ntas de alface. A partir do s isolados identificados , fo ram caracterizada s as variações patogênicas através de diferenciadoras de raça. Para esta finalidade foram utilizadas Patriot ( suscetível às raças 1, 2 e 3 ), Costa Rica ( resistente à raça 1 ; suscetível às raças 2 e 3 ), Summer Green ( suscetível às raças 1 e 3 ; resistente à raça 2 ) e Banchu Red Fire ( suscetível às raças 1 e 3, resistente à raça 2 ) . Os resultados obtidos identificaram a ocorrência da raça 3 de Folac. Este é o primeiro relato de ocorrência desta raça no Brasil . A partir do isolado selecionado como sendo o mais agressivo , e caracterizado como pertencente a raça 3 , r ealizou - se a triagem de genótipos de alface, afim de identificar fontes de resistência para uso em programas de melhoramento . No total de 63 genótipos testados apenas Onondaga, Itha ca, Sudenvil e JP - 11 apresentara m - se como resistente a raça 3 de Fusarium oxysporum f.sp. lactucae / The fusarium wilt, caused b y the soil fungus Fusarium oxysporum f.sp. soil lactucae is one of the most severe diseases that attack lettuce crop worldwide. In 2011, were found in a pla nting lettuce in Capão Bonito and Campinas in São Paulo, symptoms characteristic of this pathogen. S ymptomatic plants were collected for pathogen identification. The optical microscope examinations revealed the presence of hyaline staining falcate macroconidia, microconidia unicellular hyaline and pathogenicity tests revealed the presence of Fusarium oxy sporum f.sp. lactucae. We performed the re - isolation of the pathogen, there by supplementing the Koch's postulate. For this purpose were used: Patriot(susceptible to races 1, 2 and 3), Costa Rica (susceptible to races 2 and 3, resistant to race 1); Summer Green (susceptible to races 1 and 3; resistant to race 2) and Banchu Red Fire (susceptible to races 1 and 3, resistant to race 2). The results show the occurrence of race 3 of Folac. This is the first report of the case in Brazil. From the isolated select ed as being the 3 most aggressive, and characterized as belonging to race 3 was held screening of lettuce genotypes in order to identify sources of resistance for use in breeding programs. From of 63 genotypes tested only Onondaga, Ithaca, Sudenvil and JP - 11 were identified as resistant to race 3 of Fusarium oxysporum f.sp. lactucae

No description available.

No description available.