Disease resistance is critical in soft red winter wheat (Triticum aestivum L.) cultivars. Leaf rust caused by Puccinia triticina Eriks and stripe rust caused by Puccinia striiformis Westend. f.sp. tritici Eriks. are destructive pathogens of wheat. From 2014 to 2015 phenotypic data was collected at diverse locations for resistance to leaf rust (North Carolina, Texas, and Virginia) and stripe rust (Arkansas, North Carolina, Georgia, Texas, and Virginia) in a Pioneer ‘25R47’ /‘Jamestown’ (P47/JT) population composed of 186 F5:9 recombinant inbred lines (RILs). Analysis of the P47/JT population identified two quantitative trait loci (QTL) for leaf rust resistance on chromosome 5B and two QTL for stripe rust resistance on chromosomes 3B and 6A. Phenotypic variation (%) explained by the putative leaf rust resistance QTL of Jamestown on 5B was as high as 22.1%. Variation explained by the putative stripe rust resistance QTL of Jamestown on 3B and 6A was as high as 11.1 and 14.3%, respectively. Jamestown is postulated to contain gene Lr18. Seedlings of 186 F5:9 recombinant inbred lines from the P47/JT population and 200 F2 seedlings from eight other crosses including Jamestown and/or the Lr18 host differential line RL6009 (Thatcher*6/Africa 43) were screened with P. triticina race TNRJJ. Genetic analysis of the populations was conducted to validate the presence of Lr18 in Jamestown. Results of linkage analysis identified SNP maker IWB41960 linked within 5 cM of gene Lr18 in all three populations. From 2016 to 2017 phenotypic data was collected at diverse locations for resistance to leaf rust (Illinois, North Carolina, and Virginia) in a ‘2013412’ (PI 667644) / VA10W-21 (PI 676295) population (412/21) composed of 157 doubled haploid (DH) lines. The 412/21 DH lines were genotyped via genotyping by sequence (GBS). Analysis of the 412/21 population identified one quantitative trait loci (QTL) region associated with adult plant resistance to leaf rust on chromosome 1B. Phenotypic variation (%) explained by the putative leaf rust resistance QTL of 2013412 on 1B was as high as 40.1%. Kompetitive allele-specific (KASP) markers KASP_S1B_8414614 and KASP_S1B_8566239 were developed as markers for use in marker assisted selection. / Ph. D. / Disease resistance to leaf rust and stripe rust is important when growing soft red winter wheat. Genetic resistance can have a benefit to cost ratio of up to 27:1, considerably better than that of fungicide treatments. From 2013 to 2017 disease data was collected across multiple locations spanning the eastern United States (Arkansas, Georgia, Illinois, North Carolina, Texas, and Virginia). DNA molecular markers were used to identify specific chromosome regions containing genes associated with leaf and stripe rust resistance. DNA markers associated with genes conferring resistance to leaf rust resistance were identified in three chromosome regions, and genes in two regions were associated with stripe rust resistance. These genes and molecular markers associated with them can be used by scientists to further enhance resistance in wheat cultivars. Another study was conducted to determine if Lr18, a gene for leaf rust resistance that has a large effect, is present in the Virginia Tech soft red winter wheat breeding material. This gene (Lr18) is known to have been introduced from an ancestral species highly related to wheat. Wheat seedlings derived from crosses between lines postulated to carry Lr18 with susceptible lines were tested for resistance to a specific strain of leaf rust lacking virulence to Lr18. Genetic analysis of the ratio of resistant versus susceptible seedlings and association between DNA molecular markers and resistant seedlings were conducted to validate the presence of gene Lr18. A molecular marker linked tightly to gene Lr18 was identified in the study. This gene was found to be widely distributed in soft red winter wheat breeding materials and the molecular marker associated with gene Lr18 will be useful for scientists to further improve resistance in wheat cultivars.

Doctor of Philosophy / Department of Plant Pathology / John P. Fellers / Harold Trick / In Kansas, wheat (Triticum aestivum L.) is severely affected by the biotrophic fungus Puccinia triticina (leaf rust). Although resistant varieties have been developed, the fungus tends to overcome new sources resistance very quickly. Plants have evolved a single gene (R genes) defense network that can recognize specific pathogen effectors (Avr), in a gene-for-gene manor. In rusts, effectors are secreted proteins responsible for inducing the uptake of nutrients and inhibit host defense responses. Identification of secreted proteins during the infection may help to understand the mode of infection of P. triticina. Little is known about molecular interactions in the pathosystem wheat-leaf rust and no Avr genes from cereal rusts have been cloned. In order to understand pathogenicity in leaf rust and generate new alternatives for disease control, the goal of this research is identify P. triticina secreted proteins from a collection of expressed genes during the infection, and to characterize putative Avr function for three candidates. From 432 EST’s derived from haustoria and infected plants, fifteen secreted proteins were identified and 10 were selected as potential avirulence candidates. Pt3 and Pt 51 are two P. triticina (Pt) candidates expressed specifically in the haustoria and encode small cysteine-rich secreted proteins. Eight candidates are expressed at early stages of infection, during spore germination and 6 days after inoculation. They are small-secreted proteins. None are repetitive elements or have nuclear localization signals. They also do not share a conserved motif with known filamentous fungus Avr proteins. Five candidates are novel proteins, two have similarity with predicted proteins, one is homologous with Hesp-379-like protein, one is homologous with superoxide dismutase, and one has a cell glucanase predicted function. Pt3, Pt12 and Pt27 were tested by transient expression experiments using co-bombardment with GUS into leaf rust resistant isogenic lines. Reduction in the expression of reporter gene GUS co-expressed with Pt27 indicates a potential avirulence factor for Lr26 in wheat.

Orientador: Luciana Rossini Pinto / Coorientador: Mauro Alexandre Xavier / Banca: Antonio de Goes / Banca: Ivan Antonio dos Anjos / Resumo: É sabido que a utilização de marcadores moleculares em programas de melhoramento constitui uma ferramenta importante, pois permite identificar indivíduos superiores em fases juvenis, acelerando o processo de desenvolvimento de cultivares. A ferrugem marrom é uma doença causada pelo fungo Puccinia melancephala responsável por grandes prejuízos no setor canavieiro. Recentemente foram desenvolvidos marcadores moleculares, 9020-F4 e R12H16, os quais flanqueiam o maior gene de resistência à ferrugem marrom, conhecido como Bru1. O presente trabalho objetivou determinar a frequência do gene Bru1 em acessos exóticos de cana-de-açúcar, cultivares brasileiras e clones do Programa IAC bem como avaliar a sua eficiência na identificação de genótipos resistentes. Através da reação de PCR utilizando os marcadores, foi possível inferir a frequência do gene Bru1, e comparar esses resultados com a classificação fenotípica das cultivares brasileiras e clones IAC (IAC, CTC, SP e RB), quanto à suscetibilidade a doença. Além disso, foi conduzido um experimento em casa de vegetação, utilizando acessos de Saccharum spontaneum, Saccharum sinense e Saccharum robustum, os quais foram inoculados artificialmente com o fungo Puccinia melanocephala e avaliados semanalmente visando determinar o grau de suscetibilidade à ferrugem marrom. Posteriormente, os resultados obtidos foram comparados com a presença ou ausência do gene Bru1. Nas cultivares brasileiras a frequência do gene Bru1 foi alta, 75,21%, porém nos acessos exóticos foi de apenas 18 %. Verificou-se que grande parte das cultivares que possuem o gene Bru1 é classificada como resistente. Nos acessos exóticos inoculados artificialmente, a correlação entre a presença dos marcadores indicativos do gene Bru1 com as notas de severidade foi baixa e não significativa, provavelmente devido à presença de outra fonte de resistência... / Abstract: It is known that the use of molecular markers is an important tool which allows the identification of superior individuals in juvenile stages speeding up the cultivar development process. Sugarcane brown rust caused by the fungus Puccinia melanocephala is among the most important sugarcane diseases. Recently, two diagnostic molecular markers (R12H16, 9O20-F4) flanking the Bru1 gene, which is pointed as the major gene conferring brown rust resistance reported for sugarcane today were publish in the literature. The present study aimed to determine the frequency of the Bru1 gene in sugarcane exotic accessions, Brazilian varieties and elite clones from IAC program as well as to evaluate the efficiency of these markers to identify resistant genotypes. By using the Bru1 markers, it was possible to infer the frequency of Bru1 gene, and compare the results with the phenotypic classification of sugarcane Brazilian varieties and IAC clones (IAC, CTC, SP and RB) for susceptibility to the disease. Moreover, S. spontaneum, S. sinense and S. robustum accessions were artificially inoculated with the fungus P. melanocephala and weekly evaluated in greenhouse conditions. The degree of brown rust susceptibility of the accessions was compared with the presence or absence of Bru1 gene markers. The frequency of the Bru1 gene in the Brazilian varieties was high (75.21%) while only 18% of the sugarcane exotic accessions showed the Bru1 gene. Most of the varieties that presented the gene were classified as resistant. Low marker-phenotypic correlation was observed for the artificially inoculated sugarcane exotic accessions, probably due to the presence of other sources of resistance or failure of the sequence complementarity of the primers in the genome of these accesses. Generally these markers proved to be efficient in the selection of genotypes resistant to brown-rust / Mestre

Made available in DSpace on 2017-03-14T14:10:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-11-30. Added 1 bitstream(s) on 2017-03-14T14:42:52Z : No. of bitstreams: 1 000878431.pdf: 1090904 bytes, checksum: 9ac29a02b8e1f613702baf21dcc23948 (MD5) / É sabido que a utilização de marcadores moleculares em programas de melhoramento constitui uma ferramenta importante, pois permite identificar indivíduos superiores em fases juvenis, acelerando o processo de desenvolvimento de cultivares. A ferrugem marrom é uma doença causada pelo fungo Puccinia melancephala responsável por grandes prejuízos no setor canavieiro. Recentemente foram desenvolvidos marcadores moleculares, 9020-F4 e R12H16, os quais flanqueiam o maior gene de resistência à ferrugem marrom, conhecido como Bru1. O presente trabalho objetivou determinar a frequência do gene Bru1 em acessos exóticos de cana-de-açúcar, cultivares brasileiras e clones do Programa IAC bem como avaliar a sua eficiência na identificação de genótipos resistentes. Através da reação de PCR utilizando os marcadores, foi possível inferir a frequência do gene Bru1, e comparar esses resultados com a classificação fenotípica das cultivares brasileiras e clones IAC (IAC, CTC, SP e RB), quanto à suscetibilidade a doença. Além disso, foi conduzido um experimento em casa de vegetação, utilizando acessos de Saccharum spontaneum, Saccharum sinense e Saccharum robustum, os quais foram inoculados artificialmente com o fungo Puccinia melanocephala e avaliados semanalmente visando determinar o grau de suscetibilidade à ferrugem marrom. Posteriormente, os resultados obtidos foram comparados com a presença ou ausência do gene Bru1. Nas cultivares brasileiras a frequência do gene Bru1 foi alta, 75,21%, porém nos acessos exóticos foi de apenas 18 %. Verificou-se que grande parte das cultivares que possuem o gene Bru1 é classificada como resistente. Nos acessos exóticos inoculados artificialmente, a correlação entre a presença dos marcadores indicativos do gene Bru1 com as notas de severidade foi baixa e não significativa, provavelmente devido à presença de outra fonte de resistência... / It is known that the use of molecular markers is an important tool which allows the identification of superior individuals in juvenile stages speeding up the cultivar development process. Sugarcane brown rust caused by the fungus Puccinia melanocephala is among the most important sugarcane diseases. Recently, two diagnostic molecular markers (R12H16, 9O20-F4) flanking the Bru1 gene, which is pointed as the major gene conferring brown rust resistance reported for sugarcane today were publish in the literature. The present study aimed to determine the frequency of the Bru1 gene in sugarcane exotic accessions, Brazilian varieties and elite clones from IAC program as well as to evaluate the efficiency of these markers to identify resistant genotypes. By using the Bru1 markers, it was possible to infer the frequency of Bru1 gene, and compare the results with the phenotypic classification of sugarcane Brazilian varieties and IAC clones (IAC, CTC, SP and RB) for susceptibility to the disease. Moreover, S. spontaneum, S. sinense and S. robustum accessions were artificially inoculated with the fungus P. melanocephala and weekly evaluated in greenhouse conditions. The degree of brown rust susceptibility of the accessions was compared with the presence or absence of Bru1 gene markers. The frequency of the Bru1 gene in the Brazilian varieties was high (75.21%) while only 18% of the sugarcane exotic accessions showed the Bru1 gene. Most of the varieties that presented the gene were classified as resistant. Low marker-phenotypic correlation was observed for the artificially inoculated sugarcane exotic accessions, probably due to the presence of other sources of resistance or failure of the sequence complementarity of the primers in the genome of these accesses. Generally these markers proved to be efficient in the selection of genotypes resistant to brown-rust

Orientador: Edson Luiz Furtado / Coorientador: Roberto Antonio Rodella / Banca: Christiane Ceriani Aparecido / Banca: Marina Aparecida de Moraes Dallaqua / Resumo: O fungo Puccinia psidii é o agente causal da doença conhecida como ferrugem. Esse patógeno ataca a cultura do eucalipto e, também, algumas espécies frutíferas da família Myrtaceae. Em áreas próximas a plantios comerciais de eucalipto podem ocorrer espécies frutíferas de mirtáceas. Se dentro dessas espécies estiver àquelas suscetíveis ao patógeno, essas servirão de fonte de inóculo para o eucalipto, sendo prejudicial para a exploração econômica da referida espécie. O estudo da variabilidade fisiólogica do patógeno P. psidii e sua relação com seu hospedeiro (no caso espécies de mirtáceas) é de suma importância para se traçar estratégias de controle e, também manejar de forma sustentável a doença na cultura do eucalipto e de mirtáceas frutíferas que são exploradas economicamente, como a goiabeira. Portanto, o projeto em questão visou o estudo da fisiologia do fungo P. psidii e sua relação com espécies frutíferas da família Myrtaceae. Especificamente, foi estudada a patogenicidade, em ambiente controlado, sobre dez espécies de mirtáceas, sendo Araçá do cerrado (Psidium cattleianum), Cabeludinha (Myrciaria glazioviana), Cereja-do-rio-grande (Eugenia involucrata), Eucalipto (Eucalyptus cloeziana); Grumixama (Eugenia brasiliensis); Jambinho (Acmena smithii), Jambo (Syzygium jambos); Jambolão (Syzygium cumini); Pitanga (Eugenia uniflora) e Uvaia (Eugenia pyriformis). Seis inóculos do patógeno foram obtidos de plantas doentes coletados na região de Botucatu/SP. Em cinco espécies, sendo Myrciaria glazioviana, Eugenia involucrata, Eucalyptus cloeziana, Acmena smithii, Syzygium jambos, foram efetuadas a caracterização anatômica foliar visando à observação de diferenças estruturais nos limbos foliares e, ainda, complementou-se à essa caracterização por meio de análise de microscopia eletrônica... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract:The Puccinia psidii fungus is the causative agent of the disease known as rust. The pathogen attacks the cultivation of eucalyptus and also some fruits species of Myrtaceae family. In areas close to commercial plantations of eucalyptus species may grow fruits from this family. If within these species are those susceptible to the pathogen, these serve as a source of inoculum for Eucalyptus, being detrimental to the economic exploitation of that species. The study of physiological variability of the pathogen P. psidii and its relationship with its host (in the case of Myrtaceae species) is of paramount importance to strategize and control, also sustainably manage the disease in the cultivation of eucalyptus and fruit Myrtaceae that are exploited economically, as the guava. Therefore, the project in question was aimed at the study of the physiology of the fungus P. psidii and its relation with fruit species of the Myrtaceae family. Specifically, we studied the pathogenicity, in a controlled environment, about ten species of Myrtaceae, being Strawberry guava (Psidium cattleianum) Yellow jaboticaba (Myrciaria glazioviana), Cherry-the-river-wide (Eugeniainvolucrata), Eucalyptus (Eucalyptus cloeziana); Grumichama (Eugenia brasiliensis); Lilly Pilly (Acmena smithii), Plum Rose (Syzygium jambos), Black Plum (Syzygium cumini); Brazilian cherry (Eugenia uniflora) and Uvaia (Eugenia pyriformis). Six of the pathogen inocula were obtained from diseased plants collected in Botucatu / SP. In five species, Myrciaria glazioviana, Eugenia involucrata, Eucalyptus cloeziana, Acmena smithii, Syzygium jambos were made anatomical characterization leaf aimed at observation of structural differences in the leaf blades and also added up to this characterization by analysis of scanning electron microscopy in order to visualize the leaf surface of each host against... (Complete abstract click electronic access below) / Mestre

Orientador: Edson Luiz Furtado / Banca: Antonio de Góes / Banca: Nara Lucia Perondi Fortes / Banca: Marina Capelari / Banca: Mario Barreto Figueiredo / Resumo: Com o objetivo de caracterizar o "complexo" gênero anamórfico Cylindrocladium, dezoito isolados foram cultivados em meios de cultura distintos, mantidos sob diferentes temperaturas, além de ter conídios e vesículas terminais analisados morfologicamente para identificação correta das culturas. Inoculações em diferentes hospedeiros foram realizadas para avaliação do comportamento patogênico dos isolados estudados. Também, o DNA destes isolados foi extraído e analisado, na tentativa de se encontrar diferenças relevantes. Com relação aos caracteres morfológicos estudados, pôde-se observar que ocorrem alterações nas dimensões de conídios e morfologia da vesícula terminal devido, provavelmente, à mudança do substrato de cultivo. Porém, a variabilidade natural nas características dessas estruturas é tão elevada que dificulte a identificação correta dos isolados. Em uma mesma cultura, por exemplo, puderam ser observadas vesículas terminais de diferentes morfologias. Também foi estudada a compatibilidade genética através do pareamento, dois a dois, dos diferentes isolados em meio de cultura feijão azuki-ágar. Observou-se que, somente em alguns pareamentos, desenvolveram-se peritécios contendo esporos sexuais do gênero teleomórfico Calonectria, correspondente ao anamorfo Cylindrocladium spp., diferente compatibilidade gênica, ou seja, distintos "mating-types". Pôde-se constatar que existem diferenças patogênicas e fisiológicas entre os isolados, uma vez que houve a formação de grupos distintos quando tais características foram consideradas. Estas diferenças, provavelmente, sejam devidas à constituição genética distinta existente entre os isolados. Porém, isto não pôde ser constatado devido às dificuldades encontradas nos experimentos relativos à caracterização molecular...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In order to characterize the anamorfic genus Cylindrocladium eighteen isolates had been cultivated in distinct media of culture, kept under different temperatures, besides having spores and terminal vesicles morphologically analyzed for correct identification of cultures. Inoculations on different hosts had been carried out through for evaluation of pathogenic behavior of the isolated studied. The genetic compatibility was studied by the cultures pareament on azuki-bean medium. Only in some plates were observed perithecia containing sexual spores (ascospores) of the teleomorphic genus Calonectria. This result indicates the existence of different mating types. Also, the DNA of these isolates were extracted and studied in the attempt to find important differences. Concerning the morphologic characters studied could be observed that alterations occur in the conidial dimensions and morphology of the terminal vesicle, but those alterations were meaningless and happen probably due the substratum changes. However, the natural variability in the general characteristics of these structures raised that it makes difficult the correct identification of the isolates. In the same culture, for example, can be observed terminal vesicles with different morphologies. It could be evidenced that pathogenic and physiological differences among the isolates exist. This brings the idea of the distinct populational groups formation when such characteristics were considered. These differences, probably, must to the existence of distinct genetic constitution among the isolates. However, this could not be evidenced due the difficulties that occur in the molecular characterization experiments. For these studies were necessary a good quality of DNA samples. Even though many different protocols for DNA extraction were used this quality was not obtained...(Complete abstract click electronic access below) / Doutor

Made available in DSpace on 2014-06-11T19:28:36Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-01-04Bitstream added on 2014-06-13T18:35:01Z : No. of bitstreams: 1 souza_rrs_me_botfca.pdf: 4134398 bytes, checksum: 35160af55248a162df54256d389a6408 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Na natureza, a maioria das plantas é resistente aos diferentes patógenos, e essa resistência pode estar relacionada à existência de substâncias tóxicas aos microrganismos. As reações bioquímicas, que ocorrem nas células do hospedeiro, produzem substâncias que se mostram tóxicas ao patógeno ou criam condições adversas para o seu crescimento no interior da planta, contribuindo significativamente para a resistência. Além dos fatores bioquímicos existem mecanismos estruturais de defesa que atuam conferindo resistência ao hospedeiro à infecção por patógenos. O presente trabalho procurou quantificar os caracteres anatômicos foliares, em três estágios (E1, E3 e E5) de desenvolvimento; analisar a patogênese de Puccinia psidii pela micromorfologia da folha e caracterizar a composição dos óleos essenciais de clones de eucalipto, a fim de relacionar esses fatores com a resistência à ferrugem, causada pelo fungo Puccinia psidii. Para o estudo anatômico e dos óleos essenciais, foram selecionados clones com diferentes graus de resistência, sendo o clone A resistente, o clone B suscetível e o clone C altamente suscetível. Para a microscopia eletrônica de varredura foram selecionados os clones A e C. Através da anatomia quantitativa da região internervural da folha, o clone A apresentou diferenças estruturais que podem estar ligadas à resistência desse material, como: maior espessura das cutículas abaxial e adaxial, maior espessura do parênquima paliçádico adaxial, maior % de parênquima paliçádico, maior número e área de cavidades oleíferas, menor espessura da epiderme abaxial e menor espessura e % de parênquima lacunoso. Estes parâmetros podem dificultar a penetração do patógeno e a sua colonização nos tecidos do hospedeiro. Além disso, o estudo anatômico... / resistance could be related to the existence of substances that are toxic to microorganisms. The biochemical reactions that take place in cells of the host produce substances that are toxic to the pathogen or create adverse conditions for their growth inside the plant, significantly contributing toward resistance. In addition to biochemical factors, there are structural defense mechanisms that act by conferring resistance to the host against infection by pathogens. This work's objective was to quantify leaf anatomical characters at three developmental stages (E1, E3, and E5); analyze Puccinia psidii pathogenesis via leaf micromorphology; and characterize the essential oils composition of eucalyptus clones, in order to establish a relationship between essential oils study, clones with different degrees of resistance were selected as follows: clone A was considered resistant, clone B susceptible, and clone C highly susceptible. Clones A and C were selected for scanning electron microscopy. By quantitative anatomy of the leaf interveinal region, clone A exhibited structural differences that could be linked to resistance in this material, such as: greater thickness of the abaxial and adaxial cuticles, greater thickness of the adaxial palisade parenchyma, greater palisade parenchyma percentage, higher number and area of oleiferous receptacles, smaller thickness of the abaxial epidermis, and smaller thickness and percentage of spongy parenchyma. These parameters can make it difficult for the pathogen to penetrate and colonize host tissues. In addition, the anatomical study allowed the discrimination of the first leaf stage in the highly susceptible clone in relation to the others, indicating a relationship between these characters and rust, since the disease occurs preferably on young leaves and organs at...(Complete abstract click electronic access below)

Submitted by Marco Antônio de Ramos Chagas (mchagas@ufv.br) on 2017-06-21T12:44:11Z No. of bitstreams: 1 texto completo.pdf: 533052 bytes, checksum: b0aaa088353b0a9f7705de0705d1f822 (MD5) / Made available in DSpace on 2017-06-21T12:44:11Z (GMT). No. of bitstreams: 1 texto completo.pdf: 533052 bytes, checksum: b0aaa088353b0a9f7705de0705d1f822 (MD5) Previous issue date: 2000-07-14 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Utilizando o tamanho das pústulas e o número de soros como critérios para avaliar a severidade, estabeleceu-se a seguinte escala de notas para quantificação da ferrugem em mudas inoculadas de Eucalyptus: S0 = imunidade ou reação de hipersensibilidade, com necrose ou “fleck”; S1 = pústulas puntiformes, < 0,8 mm de diâmetro, com uma ou duas uredínias; S2 = pústulas medianas, de 0,8 a 1,6 mm de diâmetro, com aproximadamente 12 uredínias; e S3 = pústulas grandes, > 1,6 mm de diâmetro, com 20 ou mais uredínias. Aferiu-se a utilidade dessa escala utilizando marcadores RAPD, geneticamente ligados a um gene de resistência à ferrugem, em uma progênie de E. grandis. Plantas das classes S0 e S1 apresentaram os referidos marcadores e foram consideradas resistentes. Plantas das classes S2 e S3 não apresentaram aqueles marcadores e foram consideradas suscetíveis. O erro na classificação entre plantas resistentes e suscetíveis foi apenas de 8%, o que se deveu à proximidade dos limites superior e inferior no tamanho das pústulas das classes S1 e S2, respectivamente. O uso dessa escala permitiu a seleção de grande número de materiais resistentes à ferrugem com relativas rapidez, facilidade e precisão. Mediante a inoculação artificial e a avaliação da severidade entre os 12 e 24 dias após a inoculação em famílias de irmãos- completos de E. grandis, identificou-se, no clone G21, um gene de efeito principal na resistência à ferrugem, aqui denominado Ppr1 (Puccinia psidii resistance, gene 1). A inclusão de plantas da classe S1 entre as plantas resistentes indicou que, além de Ppr1, outros genes de efeito secundário podem atuar na resistência à ferrugem. Esse foi o primeiro caso de identificação de um gene de resistência à ferrugem em Eucalyptus e um dos poucos genes de efeito principal em patossistema não co-evoluído. Utilizando uma progênie de E. grandis, constituída de 994 indivíduos segregantes para resistência à ferrugem, identificaram-se seis marcadores RAPD ligados ao gene Ppr1. O marcador AT9/917 apresentou completa co-segregação com o gene Ppr1 em todas as plantas segregantes avaliadas, indicando localizar-se a uma distância genética máxima estimada de 0,462 cM de Ppr1. Esse marcador foi clonado e seqüenciado, não revelando homologia significativa com seqüências depositadas em bancos de dados. No entanto, esse marcador poderá ser utilizado na clonagem posicional de Ppr1. / Based on the number of sorus and pustule size, a rating scale was developed for evaluation of rust severity in inoculated seedlings of Eucalyptus as follow: S0 = immunity or hypersensitive reaction, with necrosis or fleck; S1 = small pustules, < 0,8 mm diameter, with one or two uredinia; S2 = medium sized pustules, from 0,8 to 1,6 mm diameter, with approximately 12 uredinia and S3 = large pustules, > 1,6 mm diameter, with 20 or more uredinia. Plants belonging to S0 and S1 classes were considered resistant and those belonging to S2 and S3 classes, susceptible. The error in the classification of resistant and susceptible plants was of only 8%. The error is due to similarities in pustule size among plants at the upper limit in the S1 class with plants at the lower limit in the S2 class. The use of this scale allows the screening of rust resistant genotypes. The segregation ratio of resistant to susceptible plants in artificially inoculated E. grandis full-sib progenies suggested that rust resistance is controlled by a major gene, designated Ppr1 (after Puccinia psidii resistance, gene 1). Inclusion of plants belonging to S1 class suggests that, besides Ppr1, other genes of minor effect can be involved in rust resistance. This is the first case of a resistance gene identified in Eucalyptus and one of the few of single inheritance in non-coevolved pathosystems. Using a full-sib progeny of 994 individuals of E. grandis, six RAPD markers linked to the Ppr1 gene were identified. The AT9/917 marker was tightly linked to Ppr1 gene, although sequence does not reveal homology with previously characterized resistance genes in other plant species. This marker can be used as a starting point to positional cloning of Ppr1. / Tese importada do Alexandria

Made available in DSpace on 2014-06-11T19:26:08Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-07-03Bitstream added on 2014-06-13T19:54:03Z : No. of bitstreams: 1 goncalves_bs_me_jabo.pdf: 365802 bytes, checksum: 971fbfa106cd14733f5d01a18df13850 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Associações entre marcadores moleculares e caracteres agronômicos importantes constituem uma ferramenta valiosa em programas de melhoramento, uma vez que podem identificar indivíduos superiores, ainda em fases juvenis, e, consequentemente, acelerar o processo de desenvolvimento de cultivares. Neste contexto, este trabalho teve por finalidade estabelecer associações entre marcadores moleculares (AFLP e SSR) e resistência e/ou suscetibilidade à ferrugem marrom (Puccinia melanocephala) da cana-de-açúcar, por meio da abordagem de mapeamento associativo. Os dados fenotípicos foram obtidos de experimentos conduzidos em Ribeirão Preto, durante março de 2010 e janeiro de 2012, em delineamento de blocos casualizados completos, DBC, com três repetições. Oitenta e três genótipos de cana-de-açúcar, incluindo cultivares comerciais e clones IAC, foram avaliados quanto a resistência à ferrugem marrom, sob condições de infecção natural. As plantas foram fenotipadas aos 10 meses após o plantio e 7 meses após o primeiro corte. A maioria dos genótipos avaliados (>71%) apresentou reação de resistência à ferrugem marrom; sendo o ciclo de cana-planta mais suscetível ao ataque do fungo do que a soqueira. A resistência à ferrugem marrom apresentou elevada herdabilidade, superior a 0,7. O painel associativo foi caracterizado com 79 pares de primer SSR e 20 combinações de AFLP, os quais detectaram 1015 marcas polimórficas. Os marcadores SCC60.8, SCA31.3, M56/E35 e M56/E37 foram correlacionados à suscetibilidade, enquanto SCB14.9 e M56/E33, ligados à resistência à ferrugem marrom. O efeito individual das marcas oscilou entre -0.37 (R2 = 0.05) e 0.24 (R2 = 0.08). Os marcadores moleculares associados à severidade à ferrugem marrom serão validados, visando explorá-los dentro do programa de melhoramento genético para identificar materiais resistentes ou mesmo eliminar alelos desfavoráveis, e, assim, acelerar os ganhos genéticos / Associations between markers and agriculturally important traits are a valuable tool for breeding programs, since they can identify superior individuals still in the initial developmental stages, and thus accelerate the cultivars development. In this context, the work aimed to establish associations between molecular markers (AFLP and SSR) and resistance and/or susceptibility to brown rust (Puccinia melanocephala) in sugarcane, using association mapping approach. The phenotypic data were obtained from field trials in Ribeirão Preto, during March 2010 and January 2012 in a randomized complete block design, DBC, with three replications. Eighty-three sugarcane genotypes, including commercial cultivars and IAC clones, were evaluated for resistance to brown rust under natural infection. The plants were phenotyped at 10 months after planting and 7 months after the first cut. Most of the evaluated genotypes (>71%) presented rust resistance reaction, with the plant cane crop cycle more susceptible to the fungus attack than the rattoon cane. Brown rust resistance showed high heritability, greater than 0,7. The whole panel was genotyped with 79 SSR primer pairs and 20 AFLP primer combinations, resulting in 1015 polymorphic markers. Markers SCC60.8, SCA31.3, M56/E35 and M56/E37 were correlated with susceptibility, while SCB14.9 and M56/E33 were associated to brown rust resistance. The individual marker effect ranged from -0.37 (R2 = 0.05) to 0.24 (R2 = 0.08). The molecular markers associated with the severity of brown rust should be validated, to be exploited in the breeding program to identify resistant materials or even eliminate unfavorable alleles, and thus accelerate the genetic gain

Made available in DSpace on 2014-06-11T19:33:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-06-24Bitstream added on 2014-06-13T19:44:32Z : No. of bitstreams: 1 000739802.pdf: 2542362 bytes, checksum: c004fe8b7c12122b0e1e928a0f1aaee4 (MD5) / Foram objetivos deste trabalho determinar a influência da temperatura e do período de molhamento foliar na epidemiologia da ferrugem alaranjada da cana-de-açúcar, o progresso epidêmico através das curvas de progresso de doença e mapear as zonas de risco de ocorrência da doença. Na primeira etapa foram utilizadas plantas da cultivar SP89-1115 com vinte dias de idade inoculadas com o fungo Puccinia kuehnii na concentração de 2 x104 de uredósporos/mL. O delineamento experimental utilizado foi inteiramente casualizado (DIC) em esquema fatorial 5x7 sendo 5 temperaturas (17,5 ; 20,0 ; 22,5 ; 25,0 e 27,5°C) e 7 períodos de molhamento foliar (0 ; 4; 8; 12; 16; 20 e 24 horas), com 3 repetições. As melhores temperaturas para o desenvolvimento da ferrugem alaranjada foram 20,0; 22,5 e 25,0°C sendo esta última a melhor nos períodos de molhamentos foliares acima de 12 horas. Na segunda etapa foram conduzidos experimentos em quatro áreas comerciais localizadas nos municípios de São Carlos, Jaboticabal e Miguelópolis no estado de São Paulo nas safras de 2009/2010, 2010/2011 e 2011/2012 respectivamente. Sendo as variedades utilizadas nas safras de 2009/2010 e 2011/2012 a RB72-454 e na safra 2010/2011 a SP 89-1115 ambas sabidamente suscetíveis à ferrugem alaranjada. O delineamento experimental utilizado foi em blocos casualizados (DBC) com quatro repetições, sendo as parcelas constituídas de quatro linhas de dez metros de comprimento, com espaçamento de 1,5 m entre linhas. A severidade da doença, que ocorreu por infecção natural, foi avaliada a cada 30 dias em cinco plantas escolhidas aleatoriamente na área útil da parcela, analisando a folha +3 de cada planta com auxílio de uma escala descritiva de notas de Amorim et al. (1987) para ferrugem marrom (Puccinia melanocephala) adaptada para a ferrugem alaranjada. Os valores dos coeficientes de determinação ajustado... / The objective of this study was to determine the influence of temperature and leaf wetness in the epidemiology of rust of sugarcane. The development was evaluated through epidemic disease progress curves and mapping risk areas of disease occurrence. In the first test was used plants of the variety SP89-1115 with twenty days of old was inoculated with the pathogen Puccinia kuehnii at a concentration of 2 x 104 urediniosporal.mL-1 The experimental design was completely randomized with a factorial arrangement 5x7, representing the interaction of five temperatures (17.5, 20.0, 22.5, 25.0 and 27.5 °C) and 7 periods of leaf wetness (0, 4, 8, 12, 16, 20 and 24 hours of leaf wetness), with 3 repetitions. The temperature for the development of orange rust of sugarcane was 20.0, 22.5 and 25.0 °C, and the best results were at 25.0 °C latter being the best leaf wetness periods over 12 hours. In the second step, experiments were in four areas located in cities of São Carlos, Jaboticabal and Miguelópolis in São Paulo state during in 2009/2010, 2010/2011 and 2011/2012 respectively. Varieties being used during the agricultural year 2009/2010 and 2011/2012 RB72-454, 2010/2011 SP 89-1115 both notoriously susceptible to leaf orange rust. The experimental design was complete randomized blocks with four repetitions and plots consisting of four rows ten feet long, with spacing of 1.5 m between rows. The disease severity occurred for natural and the evolutions were made every 30 days in five randomly chosen plants in each parcel, analyzing +3 leaf of each plant with the aid of a descriptive scale. The coefficients of determination adjusted (R*2), standard deviation of the initial inoculum (x0) and infection rate (r*) confirmed that the monomolecular model was the best fit to the data of leaf orange rust of sugarcane when compared to other treatments and in all agricultural year. In the third stage with the ...