Zugl.: Halle (Saale), Univ., Diss., 2008

Made available in DSpace on 2014-06-11T19:28:36Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-01-05Bitstream added on 2014-06-13T20:18:26Z : No. of bitstreams: 1 macleod_reo_me_botfca.pdf: 551884 bytes, checksum: daa17acc87e8d6d276c281d07146254f (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) / A concentração de dióxido de carbono (CO2) da atmosfera vem aumentando desde 1750 com o advento da Revolução Industrial. Este aumento considerável, devido às atividades antrópicas, poderá alterar o cenário atual dos problemas fitossanitários em algumas décadas. O presente estudo teve como objetivo avaliar o efeito do aumento da concentração de CO2 do ar sobre a ferrugem do eucalipto, causada pelo fungo Puccinia psidii, em mudas de dois clones de eucalipto: um híbrido de Eucalyptus urophylla x E. camaldulensis (VM 01) e a espécie E. urophylla (MN 463), e ainda o efeito do CO2 sobre o desenvolvimento das plantas. Foram realizados experimentos em sala climatizada com as concentrações de 390, 405, 520 e 700 μmol mol-1 e em estufas de topo aberto (“Open top chambers”, OTCs), em campo. Nos experimentos em OTCs, foram avaliados três tratamentos: controle sem estufa e sem injeção de CO2 (concentração média de 399 μmol mol-1), controle com estufa sem injeção de CO2 (concentração média de 412 μmol mol-1) e estufa com injeção de CO2 (concentração média de 508 μmol mol-1). A inoculação foi realizada via pulverização de ambas as faces das folhas com suspensão de 2 x 104 urediniósporos mL-1 de P. psidii, aos 68 e 62 dias após a implantação do experimento em sala climatizada e nas OTCs, respectivamente. De acordo com os resultados dos experimentos, clones de VM 01 cultivados em ambiente enriquecido com CO2 apresentaram menor área lesionada, número médio de pústula por folha, número de uredínias por amostra e número médio de esporo por uredínia, diferindo significativamente das plantas controle. Em clones de MN 463 não foram observadas lesões, resposta de hipersensibilidade e esporulação de P. psidii. Com relação às análises de teor de carbono das plantas, observou-se que não houve... / The concentration of carbon dioxide (CO2) in the air has increased since 1750 due to the advent of the Industrial Revolution. This considerable increase by anthropogenic activities may exert several effects on the current situation of phytosanitary problems in a few decades. The present study aimed to evaluate the effect of increasing CO2 concentration in the air over the eucalyptus rust, caused by the fungus Puccinia psidii in seedlings of two eucalyptus clones, a hybrid of Eucalyptus urophylla x E. camaldulensis (VM 01) and E. urophylla (MN 463) species, and the effect of CO2 on plants growth. Experiments in a climatized room with concentration of 390, 405, 520 and 700 μmol mol-1 and field in open-top chambers (OTCs) were performed. In experiments with OTCs, three types of treatments were evaluated: control without OTC and without CO2 injection (average concentration of 399 μmol mol-1), control with OTC and without CO2 injection (average concentration of 412 μmol mol-1) and OTC with CO2 injection (average concentration of 508 μmol mol-1). Spray inoculation with a suspension of 2 x 104 mL-1 uredinispore of P. psidii on both sides of the leaves was performed after 68 and 62 days of implantation of the experiment in climatized room and in OTCs, respectively. According to the results of experiments, VM 01 clones cultivated in environment enriched with CO2 had shown less injured area, fewer average number of pustules per leaf, fewer number of uredinias per sample and fewer mean number of uredinia were scored by spores, differing significantly from the control plants. In MN 463 clones there were no injuries, hypersensitivity response and sporulation of P. psidii on leaves. Regarding the analysis of carbon content of plants, it was observed no differences between the treatments... (Complete abstract click electronic access below)

Made available in DSpace on 2014-06-11T19:28:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-08-10Bitstream added on 2014-06-13T19:16:45Z : No. of bitstreams: 1 masson_mv_me_botfca.pdf: 785049 bytes, checksum: d14218db7dc7bd5532a0e7f84f0ca1f2 (MD5) / Este trabalho teve como objetivos: a) realizar estudos epidemiológicos que permitiram identificar regiões do extremo Sul do Estado da Bahia propícias ao plantio de eucalipto e desfavoráveis à ferrugem causada por Puccinia psidii, dentro do princípio de evasão; b) quantificar os danos ocasionados pela doença no campo; c) avaliar a viabilidade do controle químico da ferrugem de forma curativa. Para caracterizar as regiões de plantio, foram coletados dados de estações climáticas, calculados os Índices de Infecção e realizado um estudo teórico. Para caracterizar a epidemia de ferrugem no campo, foram instaladas parcelas de observação (4 blocos com 08 clones cada) em cinco diferentes regiões edafoclimáticas de plantio pertencentes à empresa Veracel Celulose. As plantas foram avaliadas atribuindo-se notas, conforme escala diagramática. No estudo de dano, foram analisadas três regiões de plantio, aferindo-se medidas de altura, e quando possível o DAP. Para o controle químico utilizou-se o delineamento em blocos ao acaso, em esquema fatorial 3 x 3 (3 produtos e 3 doses), sendo 0,5, 1,0 e 1,5 mL ou g de Produto concentrado por Litro de solução. O ensaio químico constou de 4 repetições, com avaliação de severidade das plantas. Os tratamentos foram: 1-) Testemunha; 2-) Fungicida Amistar WG (azoxistrobina – estrobilurina); 3-) Fungicida Folicur 200 CE (tebuconazol – triazol); 4-) Fungicida Nativo SC (tebuconazol – triazol + trifloxistrobina – estrobilurina). Verificou-se que a área de plantio do extremo sul do estado da Bahia, apresentou no ano de 2008, três regiões críticas para a ocorrência de ferrugem (Oeste, Central B e Norte). A epidemia no campo apresentou duas fases: uma de crescimento e outra de decréscimo dos sintomas. A ferrugem do eucalipto disseminou-se, de um modo geral, no sentido da linha de plantio. O maior dano médio causado pela ferrugem... / This study aimed to: a) epidemiological studies to identify regions of the extreme south of Bahia State conducive to the planting of eucalyptus and unfavorable to rust caused by Puccinia psidii within the principle of avoidance, b) quantify the damage caused by the disease in the field, c) assess the feasibility of chemical control rust in the healing. To characterize the regions of planting, data were collected from weather stations, calculated the Rates of infection and made a theoretical study. To characterize the epidemic of rust in the field, plots were installed for observation (4 blocks with 08 clones each) in five different climatic regions of plantation belonging to the company Veracel Celulose. The plants were evaluated giving up notes as diagrammatic scale. In the study of damage, were examined three regions of planting, checking up measures time, and where possible the DAP. For chemical control using the design in randomized blocks in factorial scheme 3 x 3 (3 products and 3 doses), with 0.5, 1.0 and 1.5 mL or g of product concentrate per liter of solution . The test chemicals consisted of 4 replicates, with assessment of severity of the plants. The treatments were: 1 -) control; 2 -) Amistar WG Fungicide (azoxystrobin - strobilurins) 3 -) 200 EC Fungicide Folicur (tebuconazole - triazole), 4 -) Nativo SC Fungicide (tebuconazole - triazole + trifloxystrobin - strobilurins). It was found that the plantation area of the southern state of Bahia, presented in 2008, three critical regions for the occurrence of rust (West, Central B and North). The epidemic in the field showed two phases: a growth and a decrease in symptoms. Eucalyptus rust has spread, in general, towards the line of planting. The highest average damage caused by eucalyptus rust in the region reached 27.08% by volume of wood at 19 months old plants. It was found that with increasing dose of fungicides, there... (Complete abstract click electronic access below)

Made available in DSpace on 2016-08-29T15:37:05Z (GMT). No. of bitstreams: 1 tese_6921_Dissertação_Ana Paula Rossi.pdf: 1124087 bytes, checksum: 114efa5d1f115fd86474428c5a36f9e1 (MD5) Previous issue date: 2013-11-06 / A ferrugem do eucalipto, causada pelo fungo Puccinia psidii Winter, é uma das doenças mais importantes dessa cultura, tornando-se necessário o conhecimento sobre do progresso dessa doença ao longo do tempo e os danos por ela causados. Diante desta problemática e da importância que o patógeno P. psidii vem apresentando à eucaliptocultura, o presente trabalho teve como objetivo realizar uma análise temporal da ferrugem no campo e quantificação de danos. Este estudo foi conduzido em campo na área experimental da Empresa Suzano Papel e Celulose, localizada no município de Mucuri-BA. Plantou-se 200 mudas do clone 2156, híbrido de Eucalyptus grandis x Eucalyptus dunnii, e 200 mudas do clone 2392, híbrido de Eucalyptus grandis x Eucalyptus urophylla, em espaçamento de 3x3 m. O delineamento experimental foi em blocos casualizados com 10 repetições, em parcelas de 10 plantas para cada tratamento, sendo os tratamentos com e sem controle químico. O experimento dividiu-se em duas fases, fase 1: iniciou-se em abril de 2005 com o plantio das mudas e adaptação das mudas em campo, avaliou-se a incidência da ferrugem do eucalipto, a altura e a biomassa das planta, sendo que a incidência da doença e altura das plantas foram avaliadas em todos os blocos do experimento e a biomassa nos blocos (1, 2, 3 e 4). Para a avaliação da biomassa foi necessário realizar o corte das plantas nesses quatro blocos, que ocorreu quando as plantas atingiram seis meses de idade; fase 2: essa fase perdurou até o ano de 2009, durante os quatro anos de experimento avaliou-se a altura e diâmetro das plantas nos seis blocos restantes (5, 6, 7, 8, 9 e 10). Com os dados de incidência realizou-se a análise temporal da ferrugem por meio da avaliação da área abaixo da curva de progresso da doença (AACPD). A quantificação dos danos causados pela ferrugem foi realizada utilizando-se as variáveis altura (m), biomassa (kg) e volume de madeira (m³) por meio de análises estatística. Quando não foi realizado o controle químico, constatou-se que o clone 2156 foi mais resistente em relação ao clone 2392, que pode ser considerado mais suscetível, pois apresentou maior AACPD. A aplicação do fungicida triadimenol (Bayfidan) foi efetivo para o clone 2392, levando à diminuição da incidência da ferrugem e proporcionando maior altura, produção de biomassa e volume de madeira das plantas. Este clone se mostrou mais suscetível à ferrugem, no entanto mais produtivo em relação ao clone 2156. / The eucalyptus rust, caused by Puccinia psidii, is one of the most important diseases of this crop, making it necessary to know about the progress of the disease over time and the damage it caused. Given the importance of this issue and that the pathogen P. psidii is presenting the eucalypts, the present study aimed to perform a temporal analysis of rust in the field and quantify damage. This study was conducted in the field in the experimental area of Suzano Pulp and Paper Company, located in the municipality of Mucuri - BA. Planted 200 seedlings of clone 2156, hybrid of Eucalyptus grandis x Eucalyptus dunnii, and 200 seedlings of clone 2392, hybrid of Eucalyptus grandis x Eucalyptus urophylla in 3x3 m spacing. The experimental design was a randomized block design with 10 replications in plots of 10 plants for each treatment, and the treatments with and without chemical control. The experiment was divided into two phases, Phase 1: started in April 2005 with the planting of seedlings and adaptation of the seedling, we assessed the incidence of eucalyptus rust, height and biomass of the plant, and the disease incidence and plant height were evaluated in all blocks of the experiment and the biomass in the blocks (1, 2, 3 and 4). For the assessment of biomass was necessary to cut the plants in these four blocks, which occurred when the plants reached six months of age; Phase 2: This phase lasted until 2009, during the four years of the experiment evaluated the height and the diameter of the plants in the remaining six blocks (5, 6, 7 , 8, 9 and 10). With incidence data was performed temporal analysis of rust by evaluating the area under the disease progress curve (AUDPC). Quantification of the damage caused by rust was performed using the time variable (m), biomass (kg) and timber volume (m³) by statistical analysis. When it was not performed chemical control, it was found that the clone 2156 was more resistant toward clone 2392, which can be considered more susceptible, as it showed greater AUDPC. The application of the fungicide triadimenol (Bayfidan) was effective for clone 2392, leading to decreased incidence of rust and providing greater height, biomass and wood volume of plants. This clone was more susceptible to rust, however more productive relative to clone 2156.

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Agradecemos a compreensão. on 2016-12-01T12:33:45Z (GMT) / Submitted by LÚCIO DE PAULA COLLETTE Collette (lucio.collette@basf.com) on 2016-12-07T19:22:08Z No. of bitstreams: 1 Collette_lp_me_jabo .pdf: 912792 bytes, checksum: 3449617266b7978c7183c84d7311ea1f (MD5) / Approved for entry into archive by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br) on 2016-12-09T13:15:23Z (GMT) No. of bitstreams: 1 collette_lp_me_jabo.pdf: 912792 bytes, checksum: 3449617266b7978c7183c84d7311ea1f (MD5) / Made available in DSpace on 2016-12-09T13:15:23Z (GMT). No. of bitstreams: 1 collette_lp_me_jabo.pdf: 912792 bytes, checksum: 3449617266b7978c7183c84d7311ea1f (MD5) Previous issue date: 2016-05-23 / A ferrugem alaranjada, causada por Puccinia kuehnii, é uma importante doença na cultura da cana-de-açúcar, causando danos econômicos significativos aos produtores. É responsável por 20-40 % de perda em toneladas de cana por hectare e, além disso, provoca redução no teor de sacarose nos colmos. Diante desse contexto, o objetivo desse estudo foi determinar a eficácia dos fungicidas fluxapiroxade, do grupo químico carboxamida, com formulação de fluxapiroxade 300 g L-1 e a formulação contendo o fluxapiroxade + piraclostrobina (167 + 333 g L-1), comparados com os fungicidas padrões piraclostrobina + epoxiconazol (133 + 50 g L-1) e azoxistrobina + ciproconazol (200 + 80 g L-1). Para tal, foram conduzidos quatro experimentos, em condições de campo, no município de Santa Rita do Passa Quatro, estado de São Paulo, entre os meses de novembro de 2012 a abril de 2014. Foram empregadas as cultivares RB72454 e SP813250, plantadas no espaçamento 1,5 m entre linhas. Os tratamentos avaliados e as dosagens (em mL de produto comercial por hectare) foram: fluxapiroxade (167, 233, 300); fluxapiroxade + piraclostrobina (350), epoxiconazol + piraclostrobina (1000) e ciproconazol + azoxistrobina (300). O fungicida ciproconazol + azoxistrobina foi acrescido de 600 mL do óleo mineral Nimbus, enquanto nos demais fungicidas adicionou-se o óleo mineral Assist a 500 mL ha-1. As aplicações dos fungicidas, em número de três, e em intervalos mensais, deram-se mediante pulverizador costal pressurizado a CO2, com 30 lb-pol2, com bicos tipo leque Teejet 8002, e volume equivalente a 150 L.ha-1. Um tratamento correspondente à testemunha não recebeu aplicação com fungicida. Adotou-se o delineamento de blocos casualizados, com quatro repetições. Cada unidade experimental foi representada por parcelas constituídas por 6,0 m de largura e 10 m de comprimento, totalizando uma área de 60,0 m². As avaliações consistiram na determinação dos índices severidade dos sintomas, empregando-se escala de notas, em número de cinco avaliações. Também foi determinada a produtividade das plantas, em termos de tonelada de colmos de cana-de-açúcar por hectare. Com os dados de severidade foi calculada a área abaixo da curva de progresso da doença (AACPD). Após análise de variância, as médias foram comparadas por meio de teste de médias, empregando-se o teste Scott-Knott a 5% de probabilidade. Todos os fungicidas, independente se isolados ou em misturas, de forma geral demonstraram eficiência quando aplicados previamente ao aparecimento de sintomas da doença, em cana da cultivar SP813250, a qual apresentou baixo índice de severidade da doença. Porém, quando aplicados em plantas já sintomáticas, da cultivar RB72454, verificou-se um comportamento diferenciado dos tratamentos, com destaque para fluxapiroxade 300 g L-1 que, em doses superiores a 233 mL pc ha-1, foi estatisticamente semelhante aos padrões piraclostrobina + epoxiconazol e azoxistrobina + ciproconazol. O fungicida fluxapiroxade + piraclostrobina (167 + 333 g L-1), na dose de 350 mL pc ha-1 foi o mais eficiente, sendo superior aos padrões, independente das condições avaliadas. / Orange rust, caused by Puccinia kuehnii, is an important disease in the sugarcane crop, causing significant economic damage to farmers. It’s responsible for the loss of 20 – 40% tons of sugarcane per hectare, and furthermore causes a reduction in sucrose content in the stems. In this context, the objective of this study was to determine the effectiveness of fluxapyroxad fungicides, from carboxamide chemical group, with fluxapyroxad formulation 300 g L -1 , and the formulation containing fluxapyroxad + pyraclostrobin ( 333 + 167 g l-1) , compared with the standards fungicides pyraclostrobin + epoxiconazole ( 133 50 + g L -1 ) and azoxystrobin + cyproconazole (200 + 80 g L -1 ). To this, four experiments were conducted under field conditions at the municipality of Santa Rita do Passa Quatro, state of São Paulo, between November 2012 to April 2014. It was used RB72454 and SP813250 cultivars, planted with 1,5 m between rows. The treatments evaluated and dosages (in mL of commercial product per hectare) were: fluxapyroxad (167, 233, 300); fluxapyroxad + pyraclostrobin (350), epoxiconazole + pyraclostrobin (1000) and azoxystrobin + cyproconazole (300). For the cyproconazole + azoxystrobin fungicide was added 600 mL of Nimbus mineral oil, while the other fungicides were added the mineral oil Assist at 500 mL ha-1. The applications of fungicides, applied three times, and with monthly intervals, were done by CO2 backpack applicator, with 30 lb-pol2, nozzles type Teejet 8002, and volume equivalent to 150 L.ha-1. A corresponding treatment as check received no fungicide application. A randomized block design with four replications was adopted. Each sample unit was represented by plots with 6.0 m width and 10 m length, with a total area of 60.0 m². The evaluations consisted in determining the rates the severity of symptoms, using grading scale in number of five evaluations. Also was determined the productivity of the plants in terms of tons of sugarcane stems per hectare.The severity data were transformed into area under the disease progress curve (AUDPC). After analysis of variance, the means were compared with means test, using the Scott-Knott test at 5% probability. All fungicides, regardless of isolated or in mixtures, demonstrated effectiveness when applied prior to the onset of symptoms of the disease in sugarcane cultivar SP813250, which showed low level of disease severity. However, when applied in already symptomatic plants, cultivar RB72454, there was a different behavior of the treatments, especially fluxapyroxad 300 g L-1 that, at doses higher than 233 mL pc ha-1 was statistically similar to standards pyraclostrobin + epoxiconazole and cyproconazole + azoxystrobin. The fungicide fluxapyroxad + pyraclostrobin (167 + 333 g L-1), at dose of 350 ml pc ha-1 was the most efficient, being higher than the standards, regardless of the conditions evaluated.

Orientador: Edson Luiz Furtado / Banca: Mário de Oliveira Neto / Coorientador: Martha Maria Passador / Banca: Christiane Ceriani Aparecido / Banca: Juliana Cristina Sodario Cruz / Resumo: A Ordem Pucciniales (=Uredinales) é constituída por fungos causadores de doenças conhecidas como ferrugens, que ocorrem em muitas espécies vegetais, como a ferrugem das mirtáceas (Puccinia psidii Winter). Diante de importantes fitopatógenos, estudos básicos sobre a biologia destas espécies, ainda são pouco realizados, o que torna os dados escassos na literatura. Cultivos axênicos facilitam tais estudos, uma vez que sendo parasitas obrigatórios, se tornam desnecessárias as constantes inoculações em espécies hospedeiras multiplicadoras para a manutenção do inóculo durante a realização de pesquisas. Desse modo, o cultivo axênico apresenta-se importante para estudos relacionados à biologia, patogenicidade e manutenção de culturas puras, sendo este um dos objetivos do presente trabalho. Com relação às doenças, alguns voláteis e metabólitos secundários produzidos, podem atuar como barreiras bioquímicas e, também estimular a germinação e o avanço de microrganismos nos tecidos vegetais. A presença de fitopatógenos e a idade do hospedeiro podem influenciar na formação e constituição dos compostos voláteis. A busca de variedades resistentes é uma alternativa de controle viável e os compostos voláteis podem ser utilizados para identificação de resistência, bem como de suscetibilidade. Foram selecionados os seguintes componentes para preparar o meio de cultura enriquecido: sais, aminoácidos, carboidratos e vitaminas, sendo produzidos três diferentes meios de cultivo axênico: ASZV, com o qual foi obtido o cultivo axênico da ferrugem do chorão (Melampsora epitea) e os meios propostos por Schenk e... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The Order Pucciniales (= Uredinales) consists of fungi that cause diseases known as rust, which occur in many plant species, such as rust of Myrtaceae (Puccinia psidii Winter). In front of important pathogens, basic studies about the biology of these species are still little performed, which makes scarce data in literature. Axenic cultures facilitates such studies, once being obligatory parasites, become unnecessary constants inoculations in host species multipliers for maintaining the inoculum during research. This way, the axenic culture presents important for studies related to biology, pathogenicity and maintenance of pure cultures, which is one of the objectives of this work. In relation to diseases, some volatile and secondary metabolites produced may act as biochemical barriers, and also stimulate germination and advance of microorganisms in plant tissues. The presence of pathogens and age of host may influence the formation and constitution of volatile compounds. The search for resistant varieties is a viable alternative to control and the volatile compounds may be used for identification of resistance as well as susceptibility. The following components were selected to prepare the culture medium enriched: salts, amino acids, carbohydrates and vitamins, which produced three different axenic culture media: medium ASZV with which it was obtained axenic culture of rust willow (Melampsora epitea), and others two media... (Complete abstract click electronic access below) / Doutor

Made available in DSpace on 2014-06-11T19:30:20Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-05-07Bitstream added on 2014-06-13T20:00:23Z : No. of bitstreams: 1 pizetta_m_me_botfca.pdf: 612022 bytes, checksum: 1972111cbc2e4ce1ca0d0b4912c74201 (MD5) / A Ordem Pucciniales (=Uredinales) é constituída por fungos causadores de doenças conhecidas como ferrugens, que ocorrem em muitas espécies vegetais, como a ferrugem das mirtáceas (Puccinia psidii Winter). Diante de importantes fitopatógenos, estudos básicos sobre a biologia destas espécies, ainda são pouco realizados, o que torna os dados escassos na literatura. Cultivos axênicos facilitam tais estudos, uma vez que sendo parasitas obrigatórios, se tornam desnecessárias as constantes inoculações em espécies hospedeiras multiplicadoras para a manutenção do inóculo durante a realização de pesquisas. Desse modo, o cultivo axênico apresenta-se importante para estudos relacionados à biologia, patogenicidade e manutenção de culturas puras, sendo este um dos objetivos do presente trabalho. Com relação às doenças, alguns voláteis e metabólitos secundários produzidos, podem atuar como barreiras bioquímicas e, também estimular a germinação e o avanço de microrganismos nos tecidos vegetais. A presença de fitopatógenos e a idade do hospedeiro podem influenciar na formação e constituição dos compostos voláteis. A busca de variedades resistentes é uma alternativa de controle viável e os compostos voláteis podem ser utilizados para identificação de resistência, bem como de suscetibilidade. Foram selecionados os seguintes componentes para preparar o meio de cultura enriquecido: sais, aminoácidos, carboidratos e vitaminas, sendo produzidos três diferentes meios de cultivo axênico: ASZV, com o qual foi obtido o cultivo axênico da ferrugem do chorão (Melampsora epitea) e os meios propostos por Schenk e... / The Order Pucciniales (= Uredinales) consists of fungi that cause diseases known as rust, which occur in many plant species, such as rust of Myrtaceae (Puccinia psidii Winter). In front of important pathogens, basic studies about the biology of these species are still little performed, which makes scarce data in literature. Axenic cultures facilitates such studies, once being obligatory parasites, become unnecessary constants inoculations in host species multipliers for maintaining the inoculum during research. This way, the axenic culture presents important for studies related to biology, pathogenicity and maintenance of pure cultures, which is one of the objectives of this work. In relation to diseases, some volatile and secondary metabolites produced may act as biochemical barriers, and also stimulate germination and advance of microorganisms in plant tissues. The presence of pathogens and age of host may influence the formation and constitution of volatile compounds. The search for resistant varieties is a viable alternative to control and the volatile compounds may be used for identification of resistance as well as susceptibility. The following components were selected to prepare the culture medium enriched: salts, amino acids, carbohydrates and vitamins, which produced three different axenic culture media: medium ASZV with which it was obtained axenic culture of rust willow (Melampsora epitea), and others two media... (Complete abstract click electronic access below)

Germinating uredospores of race C17 of Puccinia graminis f.sp. tritici form characteristic infection structures (appressorium, infection peg, vesicle, infection hypha) in response to a 1.5 h heat shock at 29° C administered 2 h after germination at 19° C. The proportion of sporelings forming infection structures was augmented by nutrients, n-nonyl alcohol and, an appropriately timed heat shock. The heat shock temperature required to induce maximum differentiation had a very precise optimum which varied slightly for each spore lot. Variations one degree above or below this optimum reduced the percent differentiation by greater than 40%. The presence of an inhibitor of protein synthesis, puromycin, in the germination medium: (1) prevented uredosporeling differentiation but had no effect on germination, (2) significantly reduced the proportion of germtubes forming appressoria, and (3) in most cases prevented the division of germtube nuclei. It was concluded that essential differentiation-specific proteins are synthesized from the onset of germination, throughout the formation of appressoria and to the completion of differentiation. These results were consistent with the observed effects of heat shock on the rate of protein hydrolysis. During germination there was a net hydrolysis of protein leading to an increase in size of the endogenous pool of free amino acids and to an increased leakage of amino acids to the germination medium. Heat shock effectively reduced the amount of endogenous free amino acids and the extent to which amino acids were lost to the medium. It was concluded that in heat shocked sporelings protein synthesis was increased relative to protein hydrolysis by comparison with the relative rates of these two processes in germinating (non-shocked) uredosporelings. Moreover, there was no net protein synthesis during the formation of infection structures induced by heat shock. The loss of amino acids to the germination medium was selective, particularly in heat shocked sporelings. / Land and Food Systems, Faculty of / Graduate

Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is an economically important foliar disease of wheat (Triticum aestivum). In the last decade, losses from stripe rust in North Dakota (ND) have increased, peaking at 5% in 2015. Three research studies were conducted to address questions on the pathogen, varietal resistance, and integrated management. The objective of the first study was to (i) identify virulent phenotypes of Pst isolates collected from ND from 2015 to 2017 and assign races, and (ii) determine the effect of temperature on in vitro urediniospore germination, latency, and lesion spread. Across the three years, five races were detected with PSTv 37 being the most common. The highest urediniospore germination occurred at 12oC followed by 16oC. Pst isolates had shorter latency at 21oC and larger lesion spread at 16oC. The objective of the second study was to evaluate seedling resistance and adult plant resistance in the North Dakota State University spring wheat breeding program using races PSTv 37 and PSTv 52. Results from seedling experiments indicated only four and two lines were resistant to PSTv 52 and PSTv 37, respectively. Adult plant resistance experiments were unsuccessful in 2019, and will be conducted again in the future. The objective of the third study was to develop fungicide timing recommendations for wheat rust (stripe and leaf) based on varietal resistance and time of disease onset. Rust developed in five of the eight field trials, and timing of disease onset was categorized by growth stage (tillering, flag leaf, or early-flowering). Results indicated fungicide application timing was influenced by timing of disease onset and varietal resistance. When rust was detected at the tillering growth stage on the susceptible variety, the best time to apply a fungicide was at Feekes 9. When rust was detected at flag leaf or beyond on a susceptible variety, a fungicide application at Feekes 10.51 provided the adequate disease reduction and protection of yield. Results from these research studies provide a better understanding of Pst, determined seedling resistance in the breeding program, and provides field data to refine management recommendations for wheat rusts in ND. / North Dakota Wheat Commission / State Board of Agricultural Research and Education

The production of cereal crops is essential to secure a future that feeds the continuously growing population. Rust fungi reduce host fitness by feeding on their living tissue and interfere with the global production of crops. Cereal rusts, like Puccinia hordei (the causal agent of barley leaf rust) and Puccinia triticina (the causal agent of wheat leaf rust), have a narrow host range and colonize only one particular species. The most durable type of resistance, non-host resistance (NHR), is the immunity of an entire plant species to all strains of a pathogen species. Exploring the genetics of NHR has proven to be challenging because most interspecific hybrids are infertile. Previously, barley Rphq2 and Rph22, which encode orthologous lectin receptor-like kinases (LecRKs), were transformed into an experimental barley line, Golden SusPtrit, and showed resistance against adapted and non-adapted leaf rust species. We used these transgenic barley lines in the current project to explore the effect of the LecRKs on four wheat leaf rust (P. triticina) isolates. We used the settling tower method to inoculate four isolates of P. triticina on Rphq2 and Rph22 transgenic families. We found that most transgenic families showed an increase in resistance compared to the non-transgenic control 750-E1. By measuring the infection frequency of the infections, we identified that P. triticina isolates 93012 and 95012 had opposite virulence effects on two barley families, Rphq2-E5 and Rph22-E2A. Although the expression levels of Rphq2 and Rph22 followed an induction trend, we did not find significant differences between the isolates. We conclude that resistance mediated by Rphq2 and Rph22 against P. triticina isolates does not involve an isolate-specific component. Thus, we propose investigating differences between rust species to further explore the molecular aspect of non-host resistance.