La protection des vignes contre les maladies cryptogamiques telles que le mildiou est assurée majoritairement par des fongicides de synthèse dont certains posent des problèmes environnementaux et sanitaires. L’induction de résistance de la vigne par des éliciteurs des réactions de défenses pourrait permettre de réduire leur utilisation. Toutefois, l’efficacité de cette stratégie est avérée en conditions de serres, mais reste plus variable au vignoble. L’efficacité des éliciteurs est conditionnée par le niveau de réponse défensif de la plante, et plus globalement, par son état physiologique. Dans ce contexte et dans le cadre de ce travail intégré au projet FUI IRIS+, l’objectif était de vérifier si des biostimulants, via leurs effets sur la physiologie de la plante, étaient susceptibles d’augmenter son niveau de réponse aux éliciteurs. Ce projet impliquait en amont le criblage d’éliciteurs et de biostimulants efficaces sur vigne. L’activation des défenses par des éliciteurs a un coût métabolique et énergétique que la plante doit assumer. Dans un premier temps, nous avons utilisé le modèle « suspensions cellulaires » afin de comparer l’impact de deux éliciteurs oligosaccharidiques sur le métabolisme primaire de la vigne. Des analyses enzymatiques et métaboliques ont permis de montrer que l’oligogalacturonide, qui a eu la plus forte capacité à activer le métabolisme secondaire associé à la défense, comparé à la laminarine, est également celui qui a eu l’impact le plus marqué sur le métabolisme primaire ; notamment sur certains glucides et acides aminés. Ainsi, l’élicitation mobilise des ressources, impacte le métabolisme primaire de la vigne et son efficacité pourrait être conditionnée par l’état physiologique global de la plante. Dans un second temps, un criblage a été réalisé afin d’identifier de nouveaux éliciteurs potentiels parmi sept fournis par le partenaire industriel. Des tests de protection contre Plasmopara viticola (agent du mildiou) réalisés sur boutures herbacées en conditions de serres, ont permis de retenir un extrait de plante codé SDN3. Les autres ont été écartés car déjà utilisés en laboratoire (l’un d’entre eux), insuffisants en terme d’efficacité, instables ou phytotoxiques. Des études in vitro et in planta ont révélé que l’activité biologique de SDN3 est liée à deux modes d’action : par activation des défenses et par effet direct contre l’agent pathogène. Dans un troisième temps, un criblage de cinq biostimulants potentiellement efficaces sur vigne était à réaliser mais aucune méthodologie de test n’était disponible au laboratoire. Ainsi, quatre dispositifs de complexités différentes ont dû être mis au point, permettant le suivi phénotypique des parties aériennes et/ou racinaires (et dans certains cas physiologique) : systèmes « godets », « rhizotron plan », « tubes » et un autre système appelé « X » (non décrit car lié à une protection industrielle). Seuls deux modèles ont montré un intérêt. En effet, le modèle « tube » a permis de montrer une augmentation du poids frais moyen par racine primaire en réponse à un apport par la voie racinaire de l’un des produits testés, codé BS3. Le modèle « X » a également mis en évidence une accélération de l’ouverture du bourgeon, et une augmentation du nombre de racines primaires en réponse à BS3 appliqué par voie racinaire. La mise au point d’applications d’éliciteurs et d’infection par P. viticola est en cours de finalisation afin de vérifier l’hypothèse de départ à l’aide de la combinaison de BS3 avec SDN3. / The protection of vineyards against cryptogamic diseases such as downy mildew is mainly ensured by synthetic fungicides, which cause serious environmental and health problems. The induction of resistance by elicitors could allow to reduce their use. However, even if their efficacy is demonstrated in greenhouse conditions, it remains quite variable in field conditions. Indeed, the efficacy of an elicitor depends on the plant’s ability to respond, or more generally, on the latter’s physiological status. In this context, part of the FUI project IRIS+, the aim of this present work is to evaluate whether biostimulants, through their effect on the plant’s physiology, would be able to increase their responsiveness to elicitors. The activation of defenses implies a metabolic and energetic cost that the plant must get in charge. First of all, we used a cell suspension model in order to compare two oligosaccharidic elicitors on the primary metabolism of grapevine. Enzymatic and metabolic analyses showed that the oligogalacturonide, which had a stronger impact on secondary metabolism related to defense, compared to laminarin, also showed a more notable impact on primary metabolism, particularly on some sugars and amino acids. The elicitation of grapevine defenses effectively turned out to require resources. Secondly, a screening was carried out to select the most effective elicitor among seven products that were provided by the company. Protection assays against Plasmopara viticola on herbaceous cuttings allowed us to identity SDN3 as the most interesting candidate. In vitro and in planta studies revealed that the mode of action of SDN3 relied on both the activation of defenses and a direct effect against the pathogen. Lastly, as no protocol, nor methodology were available in our laboratory to screen biostimulants, four systems were developed, in order to monitor phenotypic traits of aerial and/or root system: the “pot” model, the “rhizotron” model, the “tubes”, and another termed “X” (no description allowed because of an industrial protection). Only the “X” model showed potential interests, since it allowed to display biostimulating effects such as the acceleration of the bud opening, and the increase of the mean number of primary roots, in response to BS3, applied to the roots. The development of the protocol to apply the elicitor and to infect with P. viticola spores are currently in progress, in order to assess the initial hypothesis by using the combination of BS3 and SDN3.

No description available.

Orientador: Laercio Luis Vendite / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Matematica, Estatistica e Computação Cientifica / Made available in DSpace on 2018-08-08T21:33:03Z (GMT). No. of bitstreams: 1 Briesemeister_Roberta_M.pdf: 814655 bytes, checksum: bf6c5b877276e48f013d98984a004dde (MD5) Previous issue date: 2007 / Resumo: As recentes mudanças climáticas no planeta, estão promovendo alterações na ocorrência e desenvolvimento de doenças de plantas. O principal gás causador desse acontecimento é o dióxido de carbono, CO2. Baseado neste fato, foi desenvolvido pela Embrapa Meio Ambiente, um experimento que trabalha com cenários futuros, tendo em vista a quantidade de CO2 presente na atmosfera. Preliminarmente foi feita uma análise estatística dos dados, verificando a área foliar lesionada, a altura das plantas primárias de soja, a nodulação e o peso seco. Com os resultados obtidos nessa análise, observamos que havia uma diferença significativa no tamanho da área foliar lesionada quando exposto a níveis diferentes de CO2. À partir desses dados, foi elaborado um modelo matemático determinístico para a previsão do crescimento da área foliar lesionada, causada pelo oídio, acoplando na taxa de crescimento da lesão a influência da quantidade de CO2. Algumas simulações foram feitas utilizando o crescimento da quantidade de CO2 da atmosfera. Com os dados existentes de anos anteriores, observamos em todos os casos, que altos níveis de CO2, provocam uma diminuição na área foliar lesionada. Muito embora exista uma diminuição nessa área, a quantidade do patógeno cresce exponecialmente no tempo. O que nos faz concluir, que em cenários futuros, haverá uma grande dissiminação na doença da soja, provocada pelo oídio / Abstract: The recently climate changes of the planet are promoving alteration in the incident and development in the plants diseases. The main gas that cause this event is the carbon dioxide, CO2. Based in this fact, it was developed by Embrapa environmental, the experiment that works with futures scenarios, looking the quality of CO2 present in the atmosphere. First of all it was made a statistic analyses of datas, verifing the leaf area that was damned, the hights of the primary soybeans plants, the nodulation and the dry weight. With the results that was gotten in this analyses, we could notice that it had a significant difference in the size of the leafs area damned when it was expose in differents levels of CO2. Starting from this datas, it was elaborated a deterministical mathematic model for crop the growing leaf area damned, caused by mildew, coupled in the growing rate of the damned area the influence of the CO2 quantity. Some simulation it were done using the growing quantity of CO2 in the atmosphere. With the presents datas of the years, we observe that in all cases, that hight level of CO2 cause the reduction of the damned leafs area. Even thought exists a reduction in this area, the quantity of pathogen grows exponentially in the times. What make us conclude, that in futures scenarios, will have a big spread in the soybean disease, caused py mildew / Mestrado / Mestre em Matemática Aplicada

O meloeiro (Cucumis melo L.) é uma frutífera largamente cultivada no Brasil, principalmente no nordeste brasileiro, onde vem alcançando grande importância econômica, visto que grande parte da produção é voltada para a exportação. Plantas da família do meloeiro, como pepino e abóbora, são afetadas pelo oídio (Podosphaera xanthii) que causa uma das doenças foliares mais destrutivas destas espécies. Este fungo apresenta diversas raças fisiológicas e a correta identificação destas é de elevada importância para o manejo da doença, pois o melhoramento de meloeiro com o emprego de genes de resistência é o método mais eficiente para o seu controle. A identificação destas raças por meio da prática tradicional de inoculações em uma série diferenciadora de variedades de meloeiro é um método laborioso e passível de erros. Devido a isso, uma alternativa seria o uso de métodos moleculares para determinar a identidade da raça de forma rápida e econômica. O presente trabalho objetivou verificar a variabilidade de isolados de P. xanthii através da técnica de AFLP e de seqüenciamento da região ITS 5.8S do rDNA. A partir de AFLP obteve-se um dendrograma no qual não houve separação de raças, origem geográfica e nem hospedeiro. Com esta técnica verificou-se alta variabilidade entre isolados, com similaridade genética máxima de 69% e similaridade mínima de 23%. Ao contrário, os mesmos isolados apresentaram seqüências idênticas através do seqüenciamento da região ITS 5.8S do rDNA. As duas técnicas são distintas e o AFLP proporciona a obtenção de maior quantidade de fragmentos e com isso mais chances de polimorfismos. O AFLP indica que os isolados testados têm composição genética heterogênea embora isto não tenha sido evidenciado com o seqüenciamento da região ITS. / Melon (Cucumis melo L.) is a largely cultivated fruit in Brazil, especially in the northeastern region where it is achieving great economic importance since a great part of its production is destined to exportation. Plants of the melon crop family, such as cucumbers and pumpkins, are affected by powdery mildew (Podosphaera xanthii) that causes one of the most destructive foliar diseases of this species. This fungus presents various physiological races and their correct identification is of great importance to determine the control of the disease since breeding with the use of resistant genes is the most effective method for its control. Identification of these races by traditional practice of inoculation in a differential series of melon varieties is a laborious method and misleading. Due to this, an alternative would be the use of molecular methods to quickly and economically determine the race identity. The present research has the objective of verifying the variability of isolated P. xanthii through the AFLP technique and sequencing of the rDNA\'s ITS 5.8S region. From the AFLP a dendrogram was obtained where there was no separation of race, geographic region or host. With this technique, a high variability among isolated samples was verified, with 69% maximum genetic similarity and 23% minimum similarity. On the other hand, the same isolated samples presented identical sequence through the sequencing of the rDNA\'s ITS 5.8S region. The two techniques are distinct and the AFLP helps get highest amount of fragments and with this more incidence of polymorphisms. AFLP indicates that the tested isolated samples have an heterogeneous genetic composition although this was not evidenced with the sequencing of the ITS region.

Atualmente, a videira Niagara Rosada é a variedade de uva de mesa mais cultivada no Estado de São Paulo, Brasil. Contudo, sua produtividade e custo de produção têm sido afetados pela ocorrência de doenças fúngicas, principalmente o míldio, causado pelo fungo Plasmopara viticola. Para o controle dessa doença, têm sido feitas pulverizações com fungicidas, as quais muitas vezes em excesso. Dentre as variáveis meteorológicas que influenciam a ocorrência de doenças fúngicas nas plantas, a duração do período de molhamento (DPM) é uma das mais importantes. A presença de molhamento sobre a superfície das plantas provê a água requerida pelos patógenos para o processo de germinação e infecção do tecido foliar. Visando a subsidiar sistemas agrometeorológicos de alerta fitossanitário, cuja finalidade é possibilitar a racionalização do uso de fungicidas, os objetivos do presente estudo foram: determinar a posição da videira com a DPM mais longa e sua relação com a DPM medida na posição padrão, a 30 cm de altura sobre o gramado; avaliar a estimativa da DPM sobre o gramado por diferentes modelos a partir de dados meteorológicos obtidos em uma estação meteorológica padrão e verificar as relações entre a DPM estimada para o gramado e a DPM medida no vinhedo; e correlacionar a epidemiologia do míldio (P. viticola) durante o ciclo da videira Niagara Rosada, sem controle químico, com as variáveis DPM medida no vinhedo (posição da videira com a DPM mais longa), DPM estimada na posição padrão sobre o gramado pelo melhor modelo, assim como com outras variáveis meteorológicas. A DPM foi medida em posição padrão sobre o gramado e em quatro diferentes posições da videira: topo da planta com a face superior do sensor voltada para sudoeste e nordeste (Topo-SW e Topo-NE) e altura dos cachos de uva com a face superior do sensor voltada para sudoeste e nordeste (Dossel-SW e Dossel-NE). A epidemiologia do míldio foi avaliada sem controle químico, utilizando-se escala de notas de 0 a 4, com nove níveis de severidade, para as folhas e cachos da videira. No estudo da variabilidade espacial da DPM, não houve diferença significativa entre a parte mais alta (1,6 m) e a parte mais baixa (1,0 m) da videira, assim como entre as faces sudoeste e nordeste das plantas. Ao se analisar a relação entre a DPM sobre o gramado e a DPM nas diferentes posições da videira obtida por meio de regressão linear simples, observou-se uma boa correlação, com R2 = 0,88. Na avaliação dos modelos de estimativa da DPM, o modelo CART foi o que teve o melhor desempenho sobre o gramado, sendo que esta estimativa também apresentou uma boa correlação com a DPM medida no interior do vinhedo. Isso permitiu concluir que é possível estimar a DPM no vinhedo de Niagara Rosada a partir de medidas ou estimativas da DPM na estação meteorológica padrão. Na modelagem do desenvolvimento do míldio, a DPM esteve presente nas melhores correlações com a severidade do míldio na videira Niagara Rosada, mostrando a grande importância desta variável para a ocorrência de doenças fúngicas nos vinhedos. / Nowadays, the \'Niagara Rosada\' grapevine is the most cultivated table grape variety in the State of São Paulo, Brazil. However, yield and production cost of this grapevine have been affected by fungal diseases, mainly downy mildew, caused by Plasmopara viticola fungus. For controlling this disease, producers have been applied an excessive number of sprays with fungicides. Among the meteorological variables that influence the occurrence of fungal plant diseases, leaf wetness duration (LWD) is one of the most important. The wetness presence on plant surface provides the water required by the phatogens to germinate and to infect leaf tissues. Aiming to subsidize the plant disease warning systems, which has as purpose to rationalize the use of fungicides in the vineyards, the objectives of the present study were: to determine the canopy position of the Niagara Rosada table grape with longer LWD and its correlation with measured standard LWD over turfgrass; to estimate LWD over turfgrass considering different models with data from a standard weather station, and to evaluate the correlation between estimated LWD over turfgrass and LWD measured in the vineyard; and to correlate downy mildew occurrence in the vineyard, without chemical control, with measured LWD at the vineyard (canopy position with longer LWD), with estimated LWD in standard condition over turfgrass for the best model, and with other meteorological variables. LWD was measured in standard condition over turfgrass and in four different canopy positions of the vineyard: at the top of the plants, with sensors facing southwest and northeast (Top-SW and Top-NE), and at the grape bunches height, with sensors facing southwest and northeast (Bottom-SW and Bottom-NE). The downy mildew epidemiology during the grapevine cycle was evaluated without chemical control, using scores ranging from 0 to 4, with nine severity levels, for leaves and bunches of grapevine. When the spatial variability of LWD was studied, no significant difference was observed between the top (1.6 m) and the bottom (1.0 m) of the canopy and also between the southwest and northeast face of the plants. The analysis of the relationship between standard LWD over turfgrass and crop LWD in different positions of the grape canopy showed a define correlation (R2 = 0.88). Among the LWD estimative methods, CART was the one with the best performance to estimate LWD over turfgrass. The results from this model also presented a good correlation with measured LWD inside the vineyard, showing that LWD can be estimated for this crop with data from a nearby standard weather station. For the downy mildew modeling, LWD also present the best correlations with disease severity in the \'Niagara Rosada\' vineyard, showing the great importance of this variable for fungal diseases occurrence in this crop.

Quinoa (Chenopodium quinoa Willd.) is a pseudocereal native to the Andean region of South America and a staple crop for subsistence farmers in the altiplano of Bolivia and Peru. Downy mildew is the most significant disease of quinoa caused by the pathogen Peronospora farinosa f.sp. chenopodii Byford. This disease greatly impacts quinoa crops with yield losses up to 99%. As fungicides are expensive for farmers, the development of resistant cultivars appears to be the most efficient means for controlling downy mildew. The quinoa germplasm bank contains high amounts of genetic diversity, some of which exhibit mildew resistance. Methods for evaluating mildew severity are important for finding resistant genotypes that are useful in breeding programs. The main objectives of this study were to evaluate and investigate downy mildew resistance in quinoa through several different methods. A simple inoculation method was developed for downy mildew disease assessment by placing a damp piece of cheesecloth on a leaf, pipetting a known spore solution onto the cloth, and subjecting the plants to specific humidity cycles in a growth chamber. After inoculation of five quinoa-breeding lines in a growth chamber, accession 0654 was found to be the most resistant, while genotypes NL6 and Sayana showed moderate resistance. Each of these genotypes displayed some potential for resistance breeding programs. Investigation of the growth and development of P. farinosa through resistant and susceptible quinoa genotypes revealed fewer sporangiophores, hyphal strands, and haustoria among leaf tissues of accession 0654 than in the susceptible Chucapaca cultivar. Peronospora farinosa growth was detected in leaf, petiole, and stem tissues with polymerase chain reaction (PCR) using ITSP primers designed from the internal transcribed spacer (ITS) region of the pathogen. Scanning electron microscopy (SEM) also revealed that P. farinosa penetrated stomata via appressoria, secreted extracellular matrices during sporangia germination, grew intercellularly in leaf and petiole tissues, and exited leaf tissue through stomata. Future research requiring knowledge of resistant quinoa genotypes, P. farinosa growth and development, or inoculation methods for large numbers of small quinoa plants would benefit from this report.

The purpose of this study was to evaluate the ultrastructural aspects of the host-pathogen relationship between the fungus Sphaerotheca pannosa (Wallr.) Lev. and a susceptible horticultural variety of floribunda rose "Eutin". Attention was given to the penetration of hyphal tubes, and their subsequent development into: haustorial elements in epidermal cells of rose. In addition, changes in the morphology of infected epidermal cells were described. Thin sections of rose leaves infected with S. pannosa were examined in a Hitachi electron microscope, model HS-7, after glutaraldehyde-acrolein fixation, OsO4-uranyl acetate staining, and embedding in Epon plastic. The components of S. pannosa haustoria consisted of a haustorial body with several lobes. The body, and the lobes, were irregular in shape, and were characteristically surrounded by thin haustorial walls. Small amounts of sheath enclosed the haustorial walls, or was found lacking around some haustorial lobes. A slender neck attached the haustorium to the surface hyphal cell, and was considered an extension of that cell, and not the haustorium. At the base of the neck, a septum which contained a central pore, separated the haustorium from the surface hyphal cell, making the haustorium an independent cell. The haustorial protoplasts were similar to hyphal cells on the surface. They contained mitochondria, ribosomes, endoplasmic reticulum, lipid bodies, and vacuoles. Muclei were not detected. Penetration of the epidermal wall of rose by hyphal tubes was accompanied by cellular proliferations on the inner surfaces of the host wall. These proliferations showed layering, and some formed collars around the penetrating tubes. Although the patterns of the proliferations differed from the normal wall layers of the host, one of the layers of the collar exhibited strands of microfibrils. Some haustoria were completely surrounded by cellular proliferations which were similar in electron density to collar material. It was thought that these proliferations were extensions of the collar which formed in response to breakdown of parasitic control. It appeared that the plasma membrane of the host was the sheath membrane, and that it also lined the cavity of the collar.

No description available.

京都大学 / 新制・論文博士 / 博士(農学) / 乙第13412号 / 論農博第2895号 / 新制||農||1085(附属図書館) / 学位論文||R3||N5322(農学部図書室) / 京都大学大学院農学研究科農学専攻 / (主査)教授 冨永 達, 教授 土井 元章, 教授 那須田 周平 / 学位規則第4条第2項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

Ten winter wheat (Triticum aestivum L.) lines selected from the 1982 International Winter Wheat Mildew and Rust Nurseries were studied to characterize gene number and mode of inheritance of powdery mildew resistance. Two experiments were conducted: 1) each of the lines was crossed to the susceptible cultivar Chancellor, which lacks any known’ gene _ for resistance, and seedlings of the parental lines, F₁, F₂, BC₁ (Chancellor X F₁), and F₃ populations were inoculated with isolate 127 of Blumeria graminis (DC.) E. 0. Speer f. sp. tritici Em. Marchal in the greenhouse and evaluated for powdery mildew reaction; 2) the ten lines were crossed with each other and to each of 13 host differential lines with known genes for powdery mildew resistance, and 300 to 800 F₂ seedlings from each cross were evaluated. All parents were resistant (Infection Type = 1-3), except for ST1-25, which had an intermediate (IT = 4-5) reaction type. Genetic analyses of crosses revealed that the resistance in C39 and SI5 is conferred by three dominant genes (Pm2, 4b, and 6), and resistance in A55-2, R107, and Bulk PV63-6 is governed by one partially dominant gene (Pm4b). Results from F₂, F₃, and BC₁ populations derived from crosses between ‘Armada’ and Chancellor, were inconsistent, but indicated that Armada has at least one dominant gene for resistance, which likely is Pm4b as suggested by others. The resistance gene in OK75R3645 most likely is an allele at the Pm3 locus, and it is probable that the resistance gene in GO4779 is Pm1. Single recessive genes were identified in VPM1 (Pm4b) and ST1-25 (Pm8). / Ph. D.