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1
Fruit, Corinne. "Métallation de pyrazines. Application à la synthèse de la septorine. Synthèses et métallations de thioamides diaziniques." Rouen, 2001. http://www.theses.fr/2001ROUES005.
Texte intégralRésumé :
Dans une première partie, la métallation de pyrazines 2,3-disubstituées a été étudiée. Selon la nature du substituant en position 2, une différence de réactivité des substrats a pu être observée. La fonctionnalisation de ces composés, via des réactions successives de métallation et l'introduction d'électrophiles appropriés, constitue une voie d'accès à des pyrazines tétrasubstituées. La métallation régiosélective sur le sommet 6 de la pyrazine associée à une réaction de couplage a permis d'effectuer une nouvelle synthèse formelle de la septorine. Dans le but d'étudier le pouvoir directeur des groupes thiocarbonylés lors de la réaction de métallation, la synthèse de nouveaux composés thiocarbonylés diaziniques a été réalisée : les thiocarboxamides et les thioamides. La thionation des amides diaziniques a conduit à la formation inattendue de thiazolodiazines. La métallation du noyau aromatique des thioamides n'a pas pu être réalisée et une réaction de S-alkylation a été observée. La métallation des thiocarboxamides pyraziniques et pyridaziniques a conduit à une régiosélectivité inattendue en position 5 du cycle. Un mécanisme de fonctionnalisation basé sur l'addition thiophile de la base lithiée a été proposé. La fonctionnalisation des thiocarboxamides, via la réaction de métallation, a permis l'obtention de nombreux composés nouveaux en série pyrazinique et pyridazinique.
2
Hastoy, Cécile. "Caractérisation de la variabilité phénotypique de ressources génétiques de Stevia rebaudiana (Bertoni) : analyse des composantes du rendement et critères de sélection en condition de production." Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0118.
Texte intégralRésumé :
La consommation excessive de sucres conduit à l’augmentation de désordres métaboliques, tels que l’obésité et le diabète. Les consommateurs souhaitent une alimentation plus saine à base de produits d’origine naturelle. Stevia rebaudiana, l’herbe sucrée du Paraguay, accumule dans ses feuilles des glycosides de stéviol (SGs) considérés comme des édulcorants naturels intenses, dont le marché est en pleine expansion au niveau mondial. Dans ce contexte, la société Oviatis implante une filière BIO de Stevia rebaudiana en Nouvelle-Aquitaine. Les objectifs de cette thèse CIFRE sont de caractériser la variabilité phénotypique d’une collection de cette espèce en vue de la mise en place future d’un programme de sélection. Les composantes du rendement, de biomasse foliaire, de quantité et qualité des SGs et de la réponse à Septoria sp. ont été finement décrites en condition de production pluriannuelle et multi-sites ou en conditions contrôlées. Ces travaux ont permis de 1) développer des outils de phénotypage métabolique, pathologique et au champ, 2) évaluer la variabilité phénotypique de cette collection de Stevia rebaudiana en condition de production et identifier les descripteurs de cette variabilité, 3) identifier les facteurs ontogéniques, abiotiques et culturaux impliqués dans la variabilité de cette collection, 4) évaluer la variabilité de réponses face à la septoriose. Ces résultats permettent d’identifier les critères de sélection de cette espèce pour une production BIO en Nouvelle Aquitaine, ainsi que des génotypes d’intérêt. Ils constituent les bases de la mise en place d’un programme d’amélioration variétale<br>Obesity and diabetes are consequences of metabolic disorders due to excessive sugar consumption. Consumers want a healthier diet with natural products. Stevia rebaudiana, the Paraguayan sweet herb, accumulates steviol glycosides (SGs) into its leaves. Considered as intense natural sweeteners, SGs represent a global market constantly increasing. In this context, Oviatis establishes a complete organic sector in the Nouvelle-Aquitaine region. The aims of this CIFRE thesis are to characterise the phenotypic variability within a collection of genetic resources, in order to implement a breeding program. Yield components, leaves biomass, SGs quality and quantity and responses against Septoria sp. were described in perennial and multi-site field conditions or in controlled conditions. This work allowed to: 1) develop tools for metabolic, pathology field-phenotyping, 2) evaluate the phenotypic variability of this Stevia rebaudiana collection in field conditions and identify variability descriptors, 3) identify ontogenic, abiotic and cultural factors implicated into phenotypic variability, and 4) evaluate response variability against septoria disease. These results led to the identification of genotypes of interest, as well as selection criteria for the organic production in Nouvelle-Aquitaine, which are the basis for the implementation of a breeding program
3
Jordan, Faron. "Strobilurin resistance in Septoria tritici." Thesis, University of Nottingham, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.478958.
Texte intégral
4
Varain, Lauriane. "Transformation avec la bactérie Agrobacterium tumefaciens de deux Ascomycètes Septoria musiva et Septoria populicola, agents phytopathogènes du peuplier." Thesis, Université Laval, 2013. http://www.theses.ulaval.ca/2013/29915/29915.pdf.
Texte intégralRésumé :
Septoria musiva (téléomorphe Mycosphaerella populorum) est un Ascomycète responsable de chancres sur tronc et jeunes branches en peupleraies et de taches foliaires en peupleraies et forêts. S. populicola (M. populicola) est responsable de taches foliaires sur peupliers. L’objectif de mon projet consiste à mettre en place un système de transformation à l’aide d’Agrobacterium tumefaciens pour ces deux champignons. A. tumefaciens est la bactérie causant la galle du collet, mais qui est utilisée couramment lors de transformation de végétaux et de champignons. Une première expérience a permis d’obtenir des transformants pour S. musiva avec le plasmide pPT1, mais aucun transformant n’a été obtenu pour S. populicola. Par la suite, un autre plasmide a été utilisé : pPL1. Cependant aucune souche transformée n’a pu être obtenue pour S. musiva, et S. populicola, malgré la vérification de différents paramètres. L’absence de transformant chez S. populicola peut être attribuée à un nombre insuffisant de conidies, tandis que pour S. musiva, un nombre insuffisant de bactéries ou un protocole de transformation non optimal pourrait expliquer les échecs successifs.<br>Seporia musiva (Mycosphaerella populorum) is an Ascomycota which causes canker and leafspot on hybrid poplar. S. populicola (M. populicola) only causes leafspot. The aim of my project was to transform these two fungi with Agrobacterium tumefaciens, a bacterium which causes Crown gall, and is commonly used to transform plant and fungi in laboratory. In a first experiment, transformation using plasmid pPT1 were successful for S. musiva, but not for S. populicola. However, no transformants were obtained from either S. musiva and S. populicola in subsequent experiments in which plasmid pPL1 was used and different parameters were tested. A possible explanation for the inhability to obtain transformants from S. populicola is the low number of conidia available for transformation experiments. In the case of S. musiva, low number of bacterial cells and non optimal protocols might explain negative results observed.
5
Bearchell, Sarah Jane. "The epidemiology of Septoria diseases of wheat." Thesis, University of Reading, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.398349.
Texte intégral
6
Qin, Ruqian. "Resistance to Septoria Musiva in Hybrid Poplar." Thesis, North Dakota State University, 2014. https://hdl.handle.net/10365/27576.
Texte intégralRésumé :
Septoria leaf spot and stem canker, caused by the fungal pathogen Mycosphaerella
populorum Thompson (Anamomorph = Septoria musiva Peck). An efficient greenhouse disease
resistance screening is essential for the development of resistant clones. Fourteen clones of
hybrid poplar were inoculated with spore suspension. A regression model with parameters
(lesion number and proportion necrotic area) is consistently and accurately predicted field
resistance categories of the most resistant and susceptible clones. In second experiments, the
infection biology of S. musiva was examined at several time points by scanning electron
microscopy (6 h, 12 h, 24 h, 72 h, 1-week and 3-week) and histological analysis (3-week, 5-week
and 7-week). Results indicated that there are differences occur following penetration between the
resistant and susceptible. Those differences provide the first clues elucidating resistance
mechanism in hybrid poplar stems. The results from this thesis will be used to improve resistance
to Septoria canker in breeding programs.<br>USDA-NIFA<br>North Dakota State University. College of Agriculture, Food Sciences and Natural Resources
7
Pijls, C. F. N. R. M. J. "Population genetics of fungicide resistance in Septoria tritici." Thesis, University of Reading, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308103.
Texte intégral
8
Collin, François. "La tolérance du blé (Triticum aestivum L.) à la Septoriose." Thesis, Paris, Institut agronomique, vétérinaire et forestier de France, 2017. http://www.theses.fr/2017IAVF0028/document.
Texte intégralRésumé :
La septoriose (pathogène Zymoseptoria tritici) est la plus importante maladie foliaire des cultures de blé en Europe. Les méthodes de lutte comprennent la résistance variétale, les stratégies d’évitement de la maladie et le recours aux fongicides. Cependant, ces stratégies n’assurent pas une protection complète des cultures de blé. La tolérance à la septoriose est une approche complémentaire qui vise justement à maintenir le rendement en présence de symptômes. La tolérance à la septoriose dépend de traits physiologiques de la plante et d’équilibres source/puits : la demande des puits (croissance des grains) doit être satisfaite malgré une disponibilité réduite des sources (capacité photosynthétique réduite par les symptômes foliaires). La surface verte du couvert, la sénescence et les composantes du rendement sont des traits potentiels de tolérance intéressants qui ont été étudiés lors de ce projet. Une étude de datamining, une expérience en serre et deux expériences au champ ont été menées pour fournir des informations complémentaires sur les mécanismes de tolérance à la septoriose. Les effets des interactions génotype × environnement sur les traits de tolérance ont été étudiés pour deux saisons × cinq localisations × neuf cultivars. La nutrition azotée et le métabolisme de quatre lignées double-haploïdes (DH, contrastées du point de vue de leur tolérance à la septoriose) ont été examinés dans une expérience en conditions contrôlées à l'UMR ECOSYS (INRA, AgroParisTech Grignon, France). Les bilans source/puits de six lignées DH contrastant pour la tolérance ont également été examinés en fonction de leurs réponses à un traitement d'égrainage, appliqué dans une expérience au champ à Hereford (Royaume-Uni). Enfin, une expérience au champ avec deux stratégies fongicides (contrôle total des maladies / lutte contre les maladies non-ciblées) a permis d’étudier la tolérance à la septoriose de six cultivars modernes (Leicestershire, Royaume-Uni). L'objectif principal était de vérifier les traits potentiels de tolérance à la septoriose sur des cultivars actuellement commercialisés. Des traits potentiels de tolérance à la septoriose ont été identifiés tels que la date d’épiaison, le faible degré de limitation des puits par les sources lors de la phase de remplissage du grain des couverts sains, la distribution verticale des surfaces foliaires favorisant des feuilles supérieures relativement grandes. Les résultats ont montré que ces caractères pourraient être sélectionnables, sans compromis avec le rendement potentiel. Enfin, le projet a également discuté du besoin de méthodes alternatives de quantification de la tolérance du blé à la septoriose, ainsi que de l'importance des variations environnementales qui doivent être prises en compte pour étudier les variations génétiques de la tolérance, mais qui pourraient également être utilisées pour identifier des environnements tolérants<br>The Septoria tritici blotch disease (STB, pathogen Zymoseptoria tritici) is the most damaging foliar infection of wheat crops in Europe. Disease management strategies include cultivar resistance, disease escape strategy and fungicides. However, these strategies have failed to provide a complete protection of wheat crops. The STB tolerance is a complementary approach which aims to maintain yield in the presence of the symptoms. The tolerance of STB relies on plant physiology and source/sink balance: the sink demand (the grain growth) must be satisfied in spite of reduced source availability (photosynthetic capacity as affected by the STB symptoms on the leaves). The green canopy area, the senescence timing and the grain yield components are interesting potential sources of tolerance that were studied in this project. A data-mining study, one glasshouse experiment and two field experiments were carried out providing complementary insights on STB tolerance mechanisms. The genotype × environment interaction effects on tolerance traits were investigated for two seasons × five locations × nine cultivars datasets. The nitrogen nutrition and metabolism of four doubled-haploid (DH) lines contrasting for STB tolerance were examined in a controlled-glasshouse experiment at UMR ECOSYS (INRA,AgroParisTech) Grignon, France. The source/sink balance of six DH lines contrasting for STB tolerance was also examined according to their responses to a spikelet removal treatment, applied in a field experiment in Hereford, UK. Finally, a field experiment with two fungicide regimes (full disease control and non-target (STB) disease control) probed the STB tolerance of six modern UK winter wheat cultivars in Leicestershire, UK. The main objective was to verify identified potential STB tolerance traits in commercial cultivars. Putative STB tolerance traits have been identified such as the early heading date, the low degree of grain-source limitation of healthy crops during the grain filling phase, the vertical canopy distribution favouring a relatively larger flag-leaf. Results showed these traits might be selectable in wheat breeding without a trade-off with the potential yield. Finally, the project also discussed the need for alternative STB tolerance quantification methods, as well as the importance of environmental variations which have to be taken into account to study genetic variation in tolerance, but which could also be used to discriminate tolerant environment
9
Schäuble, Andreas. "Septoria Tritici - Bedeutung, Biologie und Bekämpfung des Erregers der Weizenblattdürre." [S.l. : s.n.], 2005. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB11759389.
Texte intégral
10
Ferreira, Junior João Batista. "Eficiência de Fungicidas no Controle da Septoriose em tomateiro Industrial /." Jaboticabal, 2016. http://hdl.handle.net/11449/147083.
Texte intégralRésumé :
Orientador: Antonio Goes<br>Coorientador: Fernanda Dias Pereira<br>Banca: Rita de Cássia Panizzi<br>Banca: Juliana Stracieri<br>Resumo: O presente trabalho teve como objetivo avaliar fungicidas de diversos grupos, isoladamente ou em mistura, no controle de Septoria lycopersici em tomateiro híbrido H-9553. Os tratamentos foram avaliados em três anos consecutivos, e constituíram nos seguintes: T1 - azoxistrobina + difenoconazol + clorotalonil; T2 - azoxistrobina + difenoconazol; T3 - clorotalonil; T4 - azoxistrobina; T5 - difenoconazol; T6 - fluazinam + clorotalonil; T7 - fluazinam; T8 - metiram + piraclostrobina + metconazol; T9 - metiram + piraclostrobina; T10 - metconazol; T11 - piraclostrobina; T12 - mancozebe; T13 - tetraconazole + tionafato metilico; T14 - tetraconazole; T15 - tiofanato metilico; T16 - ciprodinil; T17 - ciprodinil + difenoconazol; T18 - testemunha (sem fungicida). O delineamento experimental adotado foi o de blocos ao acaso, com quatro repetições. Cada unidade amostral foi representada por área de 31,25 m2 . As pulverizações, em número de 18, foram realizadas mediante pulverizador pressurizado a CO2, a 50 lb pol2, em intervalos de 7 dias e volume de 400 L ha-1 . Foram realizadas 17 avaliações, em intervalo semanal, nas três linhas centrais, em área de 18,75 m2 . Nas avaliações determinou-se a severidade dos sintomas, mediante escala de notas que variaram de 0 (ausência de sintomas) a 5 (severidade máxima). A partir do conjunto de dados foi determinada a área abaixo da curva de progresso da doença (AACPD). Adicionalmente, foram avaliadas a produtividade, em kg ha-1,... (Resumo completo, clicar acesso eletrônico abaixo)<br>Abstract: The present study aim to evaluate various groups fungicides, alone or in combination, working on the control of Septoria lycopersici in hybrid tomato plant H-9553. The treatments were evaluated during three consecutive years, and was consisted in the following: T1 - azoxystrobin + difenoconazol + clorotalonil; T2 - azoxystrobin + difenoconazol; T3 - clorotalonil; T4 - azoxystrobin; T5) difenoconazol; T6) fluazinam + clorotalonil; T7 - fluazinam; T8 - metiram + piraclostrobina + metconazol; T9 - metiram + piraclostrobina; T10 - metconazol; T11 - piraclostrobina; T12 - mancozeb; T13 - tetraconazole + tionafato metilico; T14 - tetraconazole; T15 - tiofanato metilico; T16 - ciprodinil; T17 - ciprodinil + difenoconazol; T18 - witness (with no fungicide). The experimental adopted model was a randomized block with four replications. Each sample unit represented by the area of 31.25 m2 . The 18 spraying were made by spray pressurized CO2, at 50 lb pol2 at 7 day intervals and volume of 400 L ha-1 . Were realized 17 evaluations in weekly intervals, in three central lines in area of 18,75 m2 . The evaluations measured the severity of symptoms, a note scale ranging from 0 (no symptoms) to 5 (maximum severity). From the data set was determined the area under the disease progress curve (AACPD). In addition they were evaluated productivity in kg ha-1 and fruit standart. All treatments were statistically different from the witness as AACPD, productivity, % of green fruits and % of rotten fruit. Five treatments highlighted positively: T1 - azoxystrobin + difenoconazol + clorotalonil; T3 - clorotalonil; T4 - azoxystrobin; T8 - metiram + piraclostrobina + metconazol e T11 - piraclostrobina<br>Mestre
11
Martinez, Granja Edgar. "Factors influencing the development of septoria blight in celery." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=70363.
Texte intégralRésumé :
Septoria blight of celery (Apium graveolens) caused by Septoria apiicola is a common disease. This work dealt with the development of a simple forecast model to time fungicide application to manage the blight. Two studies were conducted to examine the effect of relative humidity (65, 88, 92, 96%, and wet) temperature (15, 20, 25, and 28 C) and exposure period (6, 12, 24, 48, 72, and 96 hr) on spore production. Spores were produced at all levels of relative humidity and temperature tested. Overall spore production increased with increasing relative humidity. The greatest and the least were produced after a 48 hr wet period at 20 and 28 C, respectively. Two regression models were developed to predict spore production as functions of relative humidity and temperature. In order to validate the infection function model a field experiment was conducted in 1989 to quantify latent period. A mean latent period beginning of 12 days, a mean latent period 50% of 14 days, and a mean latent period ending of 19 days were established. Two regression models were developed to predict latent period beginning and latent period ending as functions of mean maximum and mean minimum temperatures. In order to develop a simple forecast model field experiments were conducted in 1989 and 1990. From these studies two simple forecast models are proposed to initiate fungicide applications: (1) Initial disease occurrence. (2) A cumulative disease severity value (CDSV) of 23. Using the forecasts proposed it is possible to reduce five to seven applications of fungicides during the celery growing season in Quebec.
12
Henze, Matthias. "Entwicklung einer anbauparameter- und witterungsabhängigen Befallsprognose von Septoria tritici." Göttingen Cuvillier, 2007. http://d-nb.info/987969234/04.
Texte intégral
13
Arraiano, Lia Susana. "Genetics of resistance of wheat to septoria tritici blotch." Thesis, University of East Anglia, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390648.
Texte intégralRésumé :
The research described in this týesis was focused on achieving a better understanding of the genetics of resistance of wheat to septoria tritici blotch (Mycosphaerella graminicola). Firstly, a detached leaf technique that could be a useful complement to field trials and an alternative to whole seedling assays in assessing cultivar resistance and investigating the genetics of the host-pathogen interaction was developed. Sets of inter-varietal substitution lines, developed at the John Innes Centre, involving known and possible sources of resistance to septoria tritici blotch, were tested with several single-pycnidium isolates in both the seedling and the adult plant stage. Two specific resistance genes were identified on chromosomes of `Synthetic 6x' and `Bezostaya 1'. A resistance gene, named Stb5, was identified using the M. graminicola isolate IP094269 and mapped on the short arm of chromosome 7D of `Synthetic 6x'. `Bezostaya I's specific resistance gene to IP0323 seems to be located in the same region as Stb6, and is indeed likely to be the same gene. `Bezostaya 1' and `Cappelle Desprez' also seemed to carry components for partial resistance. Triticum macha resistance to septoria tritici blotch on the other hand was both of a specific and isolatenon- specific nature. The specific components carried by T. macha seemed to be the Stb6 gene and an additional resistance gene, but it was not possible to identify their chromosomal location. To evaluate the relationship of heading date and plant height components to severity of septoria tritici blotch, an F6 single seed population of `Apollo' x `Thesee' was studied in natural conditions. Septoria tritici blotch levels were substantially lower in later-heading than in earlier-heading lines. Total plant height had comparatively little effect on disease severity, but increased distance between the two upper leaves increased disease levels. `Apollo' seems to carry partial resistance involving more than one QTL.
14
Call, Robert E., and Michael E. Matheron. "Managing Septoria Leaf Spot of Pistachio in Arizona With Fungicides." College of Agriculture, University of Arizona (Tucson, AZ), 2002. http://hdl.handle.net/10150/223661.
Texte intégralRésumé :
Septoria leaf spot was detected in the United States for the first time in 1964 within an experimental pistachio planting at Brownwood, Texas. The first observation of the same disease in Arizona pistachio trees did not occur until 1986. In 1988, a survey of the 2,000 acres of pistachio orchards in southeastern Arizona revealed a widespread incidence of the disease. Since the initial discovery of the disease, Septoria leaf spot has appeared annually in some Arizona pistachio orchards. The onset and severity of the disease is influenced by summer rainfall that occurs in this region. Pistachio trees infected with Septoria leaf spot and not treated with an effective fungicide can defoliate in the autumn up to 2 months prematurely. The objective of this field study was to evaluate the efficacy of several different fungicides against this disease. All fungicides were applied to tree foliage on June 26 and July 31, 2001. Disease severity was lowest on trees treated with Flint (trifloxystrobin) and Abound (azoxystrobin). Other materials that significantly reduced the final level of disease compared to nontreated trees included Break (propiconazole), Procop R (copper hydroxide) and Elite (tebuconazole).
15
Baldicera, Alana Karine. "Desempenho de fungicidas no controle de Septoria lycopersici em tomateiro." Universidade do Estado de Santa Catarina, 2014. http://tede.udesc.br/handle/handle/2386.
Texte intégralRésumé :
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Previous issue date: 2014-08-11<br>Tomato (Solanum lycopersicum L.) is the second major horticultural crop in the world and it is necessary a high technological level and intensive labor for develop it, which increase its economic and social values. Several plant pathogenic fungi affect this crop, which causes an excessive use of chemicals, thereby increasing the cost of production. Septoria lycopersici, causal agent of Septoria leaf spot, occur in all tomato-producing areas around the world and causes severe losses on high humidity conditions. Management techniques as crop rotation, chemical seed treatment, systemic and contact fungicides has been used to control the disease. The aims of this work were: a) to evaluate the protective and curative activity of the fungicides b) to determinate the effective dose (ED50);. Septoria strains were obtained from symptomatic tomato leaves of tomato cultivars located at several production areas. Active ingredients used in the assay of the curative effect were thiophanate-methyl, mancozebe, difenoconazol and metconazol, in commercial rates. The fungicides were applied to plant at 12; 24; 36; 48; 72 and 96 hours after inoculation. To evaluate the protective activity were used the fungicides azoxystrobin, chlorothalonil, mancozebe and captan, in commercial rates. Plants were sprayed with spore suspension at 12; 24; 36; 48; 72 and 96 hours after the application of fungicides. Germination index was evaluated in the in vitro assays, using different concentrations of thiophanate-methyl and mancozebe (0,1;1;10;100 e 1000 mg.L-1 active ingredient). Data were subjected to analysis of variance and differences assessed using the method of Tukey (p < 0,05). All analysis were performed using the software R. Difenoconazol and metconazol were the more effective curative treatments, while azoxystrobin and chlorothalonil showed the best protective activity<br>O tomate (Solanum lycopersicum L.) é a segunda hortaliça mais produzida no mundo e o seu cultivo exige alto nível tecnológico e intensa mão de obra, o que eleva a importância econômica e social da cultura. Essa hortaliça é afetada por doenças fúngicas, exigindo gastos adicionais com agrotóxico, elevando os custos de produção. A septoriose ou mancha-de-septoria causada pelo fungo Septoria lycopersici possui importância no tomateiro em locais de alta pluviosidade ocorrendo em quase todas as regiões produtoras do Brasil e do mundo. O presente trabalho teve como objetivos: a) avaliar a ação curativa preventiva e dos fungicidas testados a) avaliar a eficiência in vitro de fungicidas sobre a germinação de conídios de S. lycopersici, c) indicar a dose efetiva - ED50; para cada isolado;. Foram obtidos isolados de S. lycopersici a partir de folhas de tomate com sintomas de septoriose de diferentes cultivares na Região do Alto Vale do Rio do Peixe. Os princípios ativos utilizados para o ação curativa foram tiofanato metílico, mancozebe, difenoconazol e metconazol nas doses comerciais. As plantas foram tratadas com os fungicidas 12; 24; 36; 48; 72 e 96 horas após a inoculação. Para avaliar ao ação preventiva os tratamentos utilizados foram azoxistrobina, clorotalonil, captana e mancozebe nas doses comerciais. Pulverizou-se a suspensão de conídios sobre todas as folhas com 12; 24; 36; 48; 72 e 96 horas após o tratamento com os fungicidas. Para o experimento in vitro avaliou-se a germinação de conídios em relação aos princípios ativos tiofanato metílico e mancozebe nas concentrações de ingrediente ativo de 0,1;1;10;100 e 1000mg.L-1. Avaliou-se a germinação de conídios. Os dados foram submetidos à análise de variância (p <0,05), e quando significativos, á análise de regressão. Foram realizadas contrastes de médias por meio de teste de Tukey a 5% de significância para comparação das médias, utilizando o programa R. Os tratamentos curativos com eficiência foram difenoconazol e metconazol. Clorotalonil e azoxistrobina apresentaram controle como preventivo. Nos testes in vitro verifica-se que os isolados coletados na Região do Alto vale do Rio do Peixe são insensíveis ao princípio ativo mancozebe e tiofanato metílico, indicando uma possível resistência a esses fungicidas
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Vidal, Tiphaine. "Intérêt de la diversité architecturale des plantes cultivées pour limiter la progression épidémique de maladies foliaires à dispersion pluviale : cas de la septoriose au sein d'associations variétales de blé." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLA012/document.
Texte intégralRésumé :
La culture d’associations de variétés sensibles et résistantes au sein d’une même parcelle permet de réduire la propagation des maladies fongiques foliaires aériennes. L’architecture des plantes a un impact sur la dispersion de spores et le microclimat, mais est rarement prise en compte dans la conception des associations. L’objectif de cette thèse était de comprendre le rôle joué par l’architecture dans des associations de variétés différant par leur niveau de résistance à une maladie dispersée par éclaboussement, la septoriose du blé, causée par Zymoseptoria tritici. Une expérimentation en conditions contrôlées a permis de quantifier des relations entre interception de spores et architecture des couverts. Des différences de densité entre couverts purs et associés ont donné lieu à une réduction du niveau de maladie sur les plantes sensibles cultivées en association par rapport à celles cultivées pures. Lors d’une expérimentation au champ, les associations de variétés de hauteurs de tiges contrastées étaient moins malades que celles ayant des hauteurs similaires. Ces résultats ont été mis en relation avec des effets de l’architecture sur la dispersion de spores et la durée d’humectation au sein des couverts. Une approche de modélisation spatialement explicite a permis d’identifier des mécanismes de dispersion par éclaboussement liés à l’architecture des couverts associés. Dans des associations de variétés de hauteurs différentes, la quantité d’inoculum éclaboussée dépendait de la surface foliaire présente au dessus des feuilles malades (effet parapluie). La quantité d’inoculum interceptée par un étage foliaire était liée à la différence de hauteur entre la source d’inoculum et l’étage foliaire (effet hauteur). Les différences de hauteur de plantes entre variétés d’une association ont modulé l’interception de spores par des feuilles résistantes (effet barrière). Nos résultats suggèrent qu’une prise en compte de l’architecture des variétés dans la conception des associations variétales permettrait de mieux maîtriser les maladies par éclaboussement<br>Growing mixtures of susceptible and resistant cultivars in the same field makes it possible to reduce the propagation of airborne fungal plant diseases. Plant architecture has an impact on spore dispersal or microclimate, but is rarely taken into account in mixture design. The objective of this work was to understand the role of canopy architecture in mixtures of cultivar of different levels of resistance to a disease dispersed by rain-splash, septoria tritici blotch, caused by Zymoseptoria tritici. A controlled conditions experiment made it possible to quantify relationships between spore interception and canopy architecture. Differences of canopy density between pure stands and mixtures led to a reduction in disease on susceptible plants grown in mixture, compared to the susceptible pure stand. During a field experiment, mixtures of cultivars with contrasted stem height were less diseased than those with similar stem height. These results were related to the effect of canopy architecture on spore dispersal and leaf wetness duration. A spatially explicit modeling approach made it possible to identify splash dispersal mechanisms related to the architecture of mixed canopies. In mixtures of cultivar with diverse plant height, the amount of splashed inoculum depended on leaf area located above diseased leaves (umbrella effect). The amount of inoculum intercepted by a leaf layer was related to its difference of height between the inoculum sources (height effect). Differences of plant height between cultivars composinga mixture modulated the interception of spores by resistant leaves, providing an increased protection of susceptible leaves (barrier effect). Our results suggest that considering cultivar architecture in the design of cultivar mixtures could make it possible to improve the management of splash-dispersed diseases
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Call, Robert E., and Michael E. Matheron. "Fungicidal Performance in Managing Septoria Leaf Spot of Pistachio in Arizona." College of Agriculture, University of Arizona (Tucson, AZ), 2000. http://hdl.handle.net/10150/223845.
Texte intégralRésumé :
Septoria leaf spot was detected in the United States for the first time in 1964 within an experimental pistachio planting at Brownwood, Texas. The first observation of the same disease in Arizona pistachio trees did not occur until 1986. In 1988, a survey of the 2,000 acres of pistachio orchards in southeastern Arizona revealed a widespread incidence of the disease. Since the initial discovery of the disease, Septoria leaf spot has appeared annually in some Arizona pistachio acreage. The onset and severity of the disease is influenced by summer rainfall that occurs in this region. Pistachio trees infected with Septoria leaf spot and not treated with an effective fungicide can defoliate in the autumn up to 2 months prematurely. The objective of this field study was to evaluate the efficacy of several different fungicides against this disease. All fungicides were applied to tree foliage on July 13 and August 10, 1999. Disease severity was lowest on trees treated with Flint (trifloxystrobin). Other materials that significantly reduced the final level of disease compared to nontreated trees included Abound (azoxystrobin), Break (propiconazole), and Procop R (copper hydroxide).
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Call, Robert E., and Michael E. Matheron. "Effective Management Tools for Septoria Leaf Spot of Pistachio in Arizona." College of Agriculture, University of Arizona (Tucson, AZ), 1998. http://hdl.handle.net/10150/220530.
Texte intégralRésumé :
Septoria leaf spot was detected in the United States for the first time in 1964 within an experimental pistachio planting at Brownwood, Texas. The first observation of the same disease in Arizona pistachio trees did not occur until 1986. In 1988, a survey of the 2,000 acres of pistachio orchards in southeastern Arizona revealed a widespread incidence of the disease. Since the initial discovery of the disease, Septoria leaf spot has appeared annually in some of the Arizona pistachio acreage. The onset and severity of the disease is influenced by summer rainfall that occurs in this region. Disease management trials conducted since 1992 have shown that as few as two applications of chlorothalonil in July and August can virtually prevent disease development. Applications of copper hydroxide or benomyl alone or in combination also effectively arrest disease development. Leaves around nut clusters on infected trees not receiving fungicide treatments were usually senescent at crop maturity, whereas leaves on treated trees showed no sign of senescence. Pistachio trees infected with Septoria leaf spot and not treated with an effective fungicide can defoliate in the autumn up to 2 months prematurely.
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Edwards, Suzanne Joy. "The mechanism of host resistance in celery to Septoria apiicola (Speg.)." Thesis, University of Liverpool, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357444.
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Hagner-Holler, Silke. "Auftreten und Biologie von Septoria petroselini (Desm.) an Petersilie (Petroselinum crispum)." Bonn : Rheinische Friedrich-Wilhelms-Universität, Institut für Pflanzenkrankheiten, 2002. http://hss.ulb.uni-bonn.de/ulb_bonn/diss_online/landw_fak/2002/hagner_holler_silke/0072.pdf.
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Sharma, Sapna. "Genetics of Wheat Domestication and Septoria Nodorum Blotch Susceptibility in Wheat." Thesis, North Dakota State University, 2019. https://hdl.handle.net/10365/29767.
Texte intégralRésumé :
T. aestivum ssp. spelta Iranian type has long been thought to potentially be the direct non-free threshing hexaploid progenitor. I evaluated a RIL population derived from a cross between CS and Iranian spelta accession P503 to identify loci suppressing free-threshabilty in P503. Identification of QTL associated with threshability in region known to harbor the Tg2A gene, and an inactive tg2D allele supported the hypothesis of Iranian spelta being derived from a more recent hybridization between free-threshing hexaploid and emmer wheat. Parastagonospora nodorum is an important fungal pathogen and secretes necrotrophic effectors that evoke cell death. In this research, a DH population segregating for Snn5 was used to saturate Snn5 region of chromosome 4B with molecular markers. The physical distance between Snn5 flanking markers was narrowed to 1.38 Mb with genetic distance of 2.8 cM. The markers developed in this study will provide a strong foundation for map-based cloning of Snn5.
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Gigot, Christophe. "Potentialités des associations de variétés pour limiter la progression épidémique de la septoriose du blé : rôle des mécanismes de dispersion des spores par la pluie dans un couvert végétal hétérogène." Phd thesis, AgroParisTech, 2013. http://pastel.archives-ouvertes.fr/pastel-00961537.
Texte intégralRésumé :
Accroître la diversité végétale au sein d'une culture par l'utilisation d'associations variétales est une stratégie qui permet de limiter la sévérité des maladies à dispersion éolienne. Les potentialités de cette pratique culturale restent à être caractérisées de manière précise dans le cas des maladies à dispersion pluviale, telle que la septoriose du blé durant sa phase épidémique. Cette maladie foliaire, due au champignon pathogène Mycosphaerella graminicola, est prédominante sur blé et est capable de causer des pertes substantielles de rendement, allant jusqu'à -40 %. Des expérimentations au champ ont été menées durant cinq années, de 2008 à 2012, sur le site INRA de Grignon (Yvelines, France), avec une association constituée de deux variétés de blé ayant des niveaux contrastés de résistance à M. graminicola, et dont les proportions étaient de une plante sensible pour trois assez résistantes. Par rapport à leur culture monovariétale respective, nous avons observé une diminution de la sévérité de la septoriose sur la plus sensible des variétés (en moyenne, 45 % de surface pycnidiale foliaire en moins sur les trois dernières feuilles), sans affecter significativement la variété plus résistante. Une méthodologie originale semi-automatisée a été développée pour quantifier le flux de spores dispersés par la pluie en conditions naturelles. Les mesures expérimentales ont permis de corréler l'intensité de plusieurs épisodes pluvieux avec la dispersion de spores au sein de différents couverts incluant des associations variétales. Un modèle mécaniste et stochastique a été développé afin de décrire la progression du potentiel de maladie au sein d'un couvert végétal hétérogène en trois dimensions. Cette approche théorique combine physique et épidémiologie, d'une part, (i) pour calculer l'interception des gouttes de pluie avec les organes végétaux et la trajectoire des gouttelettes d'éclaboussement au sein du couvert et, d'autre part, (ii) pour prendre en compte les niveaux de résistance variétale et la nature polycyclique de l'épidémie. À partir de ce modèle, il a été mis en évidence pour des associations de deux variétés que les proportions, ainsi que le différentiel de résistance entre les variétés à associer, pouvaient être optimisées pour réduire la sévérité de la maladie. Par ailleurs, ce modèle permet d'évaluer et d'identifier les distributions spatiales des variétés les plus propices à une réduction de la progression d'une maladie à dispersion pluviale. Parmi les précédents travaux traitant des potentialités des associations de variétés pour lutter contre des pathogènes dispersés par l'action mécanique de la pluie, certains avançaient des conclusions souvent contradictoires et peu en faveur de cette pratique. Nous avons montré ici qu'il est possible sous certaines conditions d'association de variétés (proportions, agencement spatial, différentiel de résistance globale) et de pluviométrie d'obtenir un effet significatif en termes de réduction de la maladie.
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Chartrain, Laætitia. "Gènes de résistance spécifique et partielle à la septoriose du blé (Mycosphaerella graminicola)." Toulouse, INPT, 2004. http://www.theses.fr/2004INPT004A.
Texte intégralRésumé :
Cette thèse avait pour objet l'étude de la génétique de la résistance à la Septoriose du blé causée par Mycosphaerella graminicola, dans plusieurs cultivars utilisés comme source de résistance en Europe et dans le monde. La résistance partielle à la Septoriose, étudiée dans une population d'haploi͏̈des doublés provenant d'un croisement entre les cultivars Arina et Riband. Est apparue non-spécifique et polygénique. Des variétés utilisées comme source de résistance dans divers programmes de sélection ont été testées avec plusieurs isolats de M. Graminicola et des gène de résistance spécifique ont été identifiés. Nous avons montré que Stb6, le gène de résistance à l'isolat IPO323 était un gène probablement très ancien, entré dans les programmes de sélection à plusieurs reprises par des sources de résistance supposées indépendantes. Chez les cultivars Courtot et Tonic, un nouveau gène de la résistance à l'isolat néerlandais IPO89011l ,a été identifié et cartographié sur le chromosome 2B. Enfin, le determinisme génétique de la résistance de sources non-européennes a été étudié dans la lignée CYMMIT Kavkaz-K4500 (KK) et la lignée portugaise TE9111. La résistance de KK est contrôlée par au moins cinq gènes de résistance spécifique : Stb6, deux nouveaux gènes, Stb10 sur le chromosome 1D et Stb12 sur le chromosome 4A, un gène qui est probablement Stb7 et un autre gène non encore caractérisé. La résistance de TE9111 est elle aussi contrôlée par une combinaison de plusieurs gènes: Stb6, probablement Stb7 et un nouveau gène, Stb11, sur le chromosome 1B. Ces résultats suggèrent que d'excellents niveaux de résistance à la Septoriose du blé pourraient être obtenus en combinant des gènes de résistance appropriés.
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Mann, Ruth Louise. "Suppression of Septoria tritici by foliar applied potassium chloride on winter wheat." Thesis, University of Wolverhampton, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322183.
Texte intégralRésumé :
The effect of foliar applied potassium chloride on Septoria tritici on winter wheat was quantified and possible modes of action investigated by in vitro, glasshouse, controlled environment and field experiments between 1996 and 1999. In vitro experiments showed that as the concentration of potassium chloride increased, mycelial growth and germination of conidia decreased (EO sos of 1.36M and 0.7M, respectively). One glasshouse and two field experiments showed a significant reduction in the leaf area affected by S. trttict after foliar application of potassium chloride compared to untreated controls. In general, application of potassium chloride reduced the leaf area affected by S. tritici by 20 -.40%. However, a significant yield increase was not observed. Potassium chloride applied to the lower leaves of winter wheat did not confer systemic acquired resistance against S. tritici on the upper leaves. Inhibition of conidial germination, on leaf surfaces by potassium chloride was observed. Similar inhibition was observed when polyethylene glycol, an inert osmoticum, was applied at the same calculated osmotic potential. During field experiments there was no significant difference in the leaf area affected by S. tritici in plots treated with potassium chloride or polyethylene glycol, although both significantly reduced the leaf area affected compared to untreated control plots. Therefore, the principal mode of action of potassium chloride was proposed to be as a result of adverse osmotic conditions caused by the salt on leaf surfaces. However, the addition of a range of adjuvants to potassium chloride did not increase the efficacy of S. tritici control in glasshouse studies. The results from this study show that potassium chloride, when applied to foliage of winter wheat can reduce the leaf area affected by S. tritici and it is proposed that this reduction was by adverse osmotic conditions caused by the salt on leaf surfaces.
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Shahrokhi-Ebrahmi-Pour, Mariam. "Studies on species of Septoria causing leaf spots of pistachio (Pistacia vera)." Thesis, Royal Holloway, University of London, 1985. http://repository.royalholloway.ac.uk/items/b6fa9998-2c1f-41ae-981d-ab9bc177d958/1/.
Texte intégralRésumé :
Two pathogens Septoria pistaciarum and S. pistacina, causing leaf spot diseases of Pistachio (Pistacia vera) were studied. The morphology and ultrastructure of the two pathogens and also the ultrastructure of the host-pathogen interface were investigated. The conidia spores of both pathogens were narrowly elongate with several transverse septae and each cell contained one nucleus. Spore length and cell number were positively correlated. Spore germination was shown in detail in S. pistaciarum. Spore germination, initially an increase in volume followed by an increase in length by cell division, and germination by the production of twin-pairs of secondary septate spores and/or hyphal germ tubes. A pattern of cell division, polarity and germination was established and an interactive model was described. The spore growth initially followed linear kinetics and then became exponential. The production of hyphal tips hecame continuous exponential at the same time and the hyphal growth unit stabilised at 40-60 urn. The germination pattern could be altered by manipulation of the nitrogen or phosphate source and levels in the medium. In the resting spore the wall was composed of three layers an outer layer (o) and two inner layers I1 and I2. Each primary septum was a duplex layer derived from I1 and I2 with an intermediate electron lucent layer. Perforation was simple with paired Woronin bodies. During increase in lengththe development of new (secondary) septa showed the crosswall material was derived from layer I2 and development was centripetal. The germ-tube wall was formed from wall layer I2 and wall layers 0 + I1 were disrupted. Secondary spores were formed enter oblastically. S. pistaciarum and S. pistacina were used in the ultrastructure of host-pathogen investigation, infection of the host by S. pistaciarum was by inoculation with conidia produced on culture whereas with S. pistacina inoculation was obtained from previously infected leaves. The spores germinated on the leaf surface and penetration was made by fine hyphae through the stomatal aperture in both species, growth of pathogen within the leaf was limited to the intercellular spaces. Penetration of the host cell wall did not occur. The hyphae were attached to mesophyll and palisade cells by an accumulation of extra-hyphal sheathing material. The initial host response to infection was shown by an accumulation of electron-dense material and disruption of the tonoplast, followed by disruption of chloroplasts and disorganisation of the host cell cytoplasm. Pycnidia were produced within the lesion. Pycnidial initials were formed in sub-stomatal spaces and spore tendrils were released on the leaf surface.
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Sidhu, Yaadwinder Singh. "Molecular tools for functional genomic analyses of the stealth pathogenesis of wheat by Zymoseptoria tritici." Thesis, University of Exeter, 2015. http://hdl.handle.net/10871/20219.
Texte intégralRésumé :
Zymoseptoria tritici is an ascomycete fungus that causes Septoria tritici leaf blotch disease, which is one of the most devastating diseases of wheat. The lack of molecular tools has withheld functional genomics and consequently has left extensive gaps in the knowledge of the biology of infection by Z. tritici. The current research was conducted to develop molecular tools in order to facilitate forward and reserves genetic screens in Z. tritici. These tools include an optimised genetic manipulation protocol, the Z. tritici strains that provide high frequency targeted genome manipulations, a strategy for gene overexpression and protein tagging, and regulatable promoters for controlled gene expression in Z. tritici. The regulatable promoters served to reveal that the Z. tritici β-(1,3)- glucan synthase (BGS1) gene encoded an essential protein, which regulated cell wall stress tolerance and was therefore, a potential drug target. In addition, these molecular tools revealed a virulence-associated role of the glyoxylate cycle in Z. tritici as inactivation of this pathway impeded pre-penetration morphogenesis, which was restored by exogenous glucose application. This result implied that Z. tritici engaged the glyoxylate cycle to produce energy though gluconeogenesis by channelling the by-products of lipolysis. This significance of the glyoxylate cycle during initiation of the bi-phasic infection cycle suggests that Z. tritici is not a hemibiotroph, but a necrotrophic pathogen with an extended asymptomatic phase of infection. Overall, the molecular tools developed in this study will facilitate large-scale functional genomic analyses to interrogate the biology of infection by Z. tritici. The resulting data will inform the development of durable control strategies to combat Z. tritici outbreaks.
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Collin, François. "The tolerance of wheat (Triticum aestivum L.) to Septori tritici blotch." Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/49156/.
Texte intégralRésumé :
The Septoria tritici blotch disease (STB, pathogen Zymoseptoria tritici) is the most damaging foliar infection of wheat crops in Europe. Disease management strategies include cultivar resistance, disease escape strategy and fungicides. However, these strategies have failed to provide a complete protection of wheat crops. The STB tolerance is a complementary approach which aims to maintain yield in the presence of the symptoms. The tolerance of STB relies on plant physiology and source/sink balance: the sink demand (the grain growth) must be satisfied in spite of reduced source availability (photosynthetic capacity as affected by the STB symptoms on the leaves). The green canopy area, the senescence timing and the grain yield components are interesting potential sources of tolerance that were studied in this project. A data-mining study, one glasshouse experiment and two field experiments were carried out providing complementary insights on STB tolerance mechanisms. The genotype/environment interaction effects on tolerance traits were investigated for two seasons five locations/nine cultivars datasets. The nitrogen nutrition and metabolism of four doubled-haploid (DH) lines contrasting for STB tolerance were examined in a controlled glasshouse experiment at UMR ECOSYS (INRA,AgroParisTech) Grignon, France. The source/sink balance of six DH lines contrasting for STB tolerance was also examined according to their responses to a spikelet removal treatment, applied in a field experiment in Hereford, UK. Finally, a field experiment with two fungicide regimes (full disease control and non-target (STB) disease control) probed the STB tolerance of six modern UK winter wheat cultivars in Leicestershire, UK. The main objective was to verify identified potential STB tolerance traits in commercial cultivars. Putative STB tolerance traits have been identified such as the early heading date, the low degree of grain-source availability of healthy crops during the grain filling phase, the vertical canopy distribution favouring a relatively larger flag-leaf. Results showed these traits might be selectable in wheat breeding without a trade-off with the potential yield. Finally, the project also discussed the need for alternative STB tolerance quantification methods, as well as the importance of environmental variations which have to be taken into account to study genetic variation in tolerance, but which could also be used to discriminate tolerant environment.
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Al-Hamar, Bader. "The effects of biotic and environmental factors on host-pathogen differential interactions in wheat- Mycosphaerella graminicola pathosystem." Thesis, University of Reading, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325133.
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Payne, Andrew Charles. "Molecular identification and characterisation of novel targets in Mycosphaerella graminicola, and the development of screening technologies for fungicide discovery." Thesis, University of Bristol, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326693.
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Samain, Erika. "Étude des interactions PGPRs/génotypes de blé tendre dans la lutte contre la septoriose." Thesis, Amiens, 2019. http://www.theses.fr/2019AMIE0027.
Texte intégralRésumé :
Septoria tritici leaf blotch (STB), causée par Mycosphaerella graminicola est considérée comme la maladie la plus dommageable du blé. Ce travail a pour objectif l'étude de la durabilité et de l'efficacité de la résistance induite (RI) des rhizobactéries promotrices de la croissance des plantes (PGPR), contre STB. À travers l'étude de plusieurs PGPRs pour leur capacité à stimuler la croissance (SCP) et d'IR chez différents génotypes de blé. Deux mélanges ont été déterminés, Mix2, composé de Paenibacillus sp. strain B2 (PB2) et de la souche AA, et Mix3, de PB2, Microbacterium SSM001 et Arthrobacter SSM004, en proportions égales. Les PGPR des Mix2 et Mix3 ont montré une colonisation racinaire ecto- et endophyte, jusqu’au stade dernière feuille (DF), avec un effet "helper" sur la colonisation racinaire par PB2. La SCP a été observée uniquement avec Mix2 et Mix3. En stress hydrique, l'RI de Mix2 et Mix3 était plus efficace que PB2. Toutefois, PB2, Mix2 et Mix3 ont montré une RI stable et durable contre STB jusqu'à DF, suggérant sa corrélation avec PB2 et dépend de la souche de M. graminicola, du génotype et du stade du blé. L'importante RI des PGPR contre STB a été confirmée au champ. En sol non-stérile, aucun impact significatif sur les communautés microbiennes du sol (CMS), par séquençage de l'ADNr 16S et ITS, n'a été montré. Mais une diminution significative de l'efficacité des PGPR a été observée, uniquement pour PB2 et Mix3, pour certaines variétés testées. L'analyse de l'expression des gènes de la RI de PB2, Mix2 et Mix3 a montré l'induction de gènes marqueurs des voies de défenses, AJ, phénylpropanoïdes et phytoalexines, FAO, avec des inductions stables de Pr1, glucanase et flavonoïde, les suggérant en tant que gènes marqueurs de la protection. Nous avons identifié un mélange de PGPR, avec une RI stable et durable contre STB et le stress hydrique, stimule la croissance du blé, et sans impact sur les CMS. Ce travail peut contribuer à la réduction de l'écart des résultats obtenus en laboratoire et au champ<br>Septoria tritici leaf blotch (STB) caused by Mycosphaerella graminicola is regarding as the most important disease in wheat. The present work aims to study the durability and efficiency of the plant-growth-promoting rhizobacteria (PGPR)-induced resistance (IR) against STB. Many of PGPR were screened, in single and co-inoculations, for their root colonization, plant growth promotion (PGP) and IR, using different wheat genotypes. However, two effective PGPR-mixtures were identified, Mix2; Paenibacillus sp. strain B2 (PB2) with an effective approval strain AA and Mix3; PB2 with Microbacterium SSM001 and Arthrobacter SSM004, in equal portions. PGPR in Mix2 and Mix3 showed ecto- and endophytic root colonization until the flag-leaf growth stage (FL), with a helper impact on root colonization by PB2. Only, with Mix2 and 3, PGP was observed. Under drought stress, the IR by Mix2 and 3 was more efficient compared to PB2. However, all of them showed high and durable IR against STB until FL, which seems to be more correlated to PB2 and depends on plant-genotype, growth-stage and M. graminicola strain. Interestingly, the high PGPR-IR against STB was confirmed under field conditions. Using the non-sterile field soil, they didn’t show significant impact on the soil microbial communities (SMC), using the 16S rDNA and ITS MEGA sequencing. But, a significant reduction in the PGPR’ efficiency was recorded, only, for PB2 and Mix3, and in some tested cultivars. Gene expression analysis of the PB2-, Mix2- and Mix3-IR showed upregulations of gene markers involved in the basal defenses, JA, phenylpropanoids & phytoalexins and ROS pathways, with stable priming inductions of Pr1, glucanase, and flavonoide, suggesting them as protection markers. We identified an effective PGPR-mixture induces high and durable and stable resistance against STB and drought stresses, promotes plant growth, and without disturbance on the SMC. The global results may help to reduce gap between laboratory and field results
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Dodd, Thomas. "The impact of Septoria tritici on the photosynthetic and carbohydrate metabolism of wheat." Thesis, University of Sheffield, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269286.
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Seneviratne, WSJM Sudeshi Lakmali. "Genomic Analysis of Septoria nodorum Blotch Susceptibility Genes Snn1 and Snn2 in Wheat." Diss., North Dakota State University, 2019. https://hdl.handle.net/10365/31700.
Texte intégralRésumé :
Septoria nodorum blotch is a disease of wheat caused by the necrotrophic fungus Parastagonospora nodorum. In the wheat-P. nodorum pathosystem, recognition of pathogen-produced necrotrophic effectors (NEs) by dominant host genes leads to host cell death, which allows the pathogen to gain nutrients and proliferate. To date, nine host gene-NE interactions have been reported in this pathosystem. Among them, the Snn2-SnTox2 interaction has shown to be important in both seedling and adult plant susceptibility. A saturated genetic linkage map was developed using a segregating population of recombinant inbred lines and a high-resolution map was then developed using F2 plants derived from a cross between the SnTox2-insensitive wheat line BR34 and the SnTox2-sensitive line BG301. Over 10,000 gametes were screened for high-resolution mapping and the Snn2 gene was delineated to a genetic interval of 0.10 cM that corresponds to a physical segment of approximately 0.53 Mb on the short arm of wheat chromosome 2D. A total of 27 predicted genes present in this region and thirteen of them were identified as strong candidates. Seven EMS-induced Snn2-insensitive mutants were generated for gene validation. Results of this study provide the foundation for cloning of Snn2. The host sensitivity gene Snn1, which confers sensitivity to SnTox1, was previously cloned. Here, allelic diversity of Snn1 was studied to identify causal polymorphisms, and to develop markers useful for marker assisted selection (MAS). Twenty-seven coding sequence haplotypes that correspond to 21 amino acid haplotypes were identified. Three SNPs were identified as the possible mutations that caused the insensitive allele in wild emmer to become the sensitive allele in domesticated wheat. In addition, four SNPs that changed the sensitive allele into insensitive alleles were identified. SNP-based markers that could detect three of those SNPs were developed. Results of this study help to increase our knowledge in wheat-NE interactions and host sensitivity gene evolution.<br>USDA – Agricultural Research Service<br>National Institute of Food and Agriculture
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El, Arbi Amel. "Isolement, identification et caractérisation des Bacillus spp. de sol d’oasis tunisien et leurs potentialités d’utilisation en lutte biologique." Thesis, Lille 1, 2016. http://www.theses.fr/2016LIL10157.
Texte intégralRésumé :
Ce travail de thèse a pour objectif la recherche et le criblage de bactéries capables de jouer un rôle important dans la lutte biologique contre les champignons phytopathogènes. L'isolement des bactéries a été réalisé à partir de sols rhizosphériques de palmier dattier. 5 souches parmi les 28 isolées présentent un pouvoir antagoniste et ont été identifiées comme membres du genre Bacillus. La présence des gènes de biosynthèse de lipopeptides a été détectée par PCR, la production des lipopeptides a été confirmée par spectrométrie de masse Maldi-TOF. Ces isolats se caractérisent aussi par leur tolérance aux stress abiotiques (salinité, température élevée et stress hydrique). La souche Bacillus sp III1 qui a montré la production de trois familles de lipopeptides (surfactine, fengycine et iturine) et qui possède le plus fort pouvoir antifongique a fait l’objet d’une évaluation de son potentiel de biocontrôle de la septoriose, principale maladie du blé. L’effet inhibiteur du filtrat de culture de la souche III1 sur la croissance et la germination de Zymoseptoria tritici, agent causal de la maladie du blé, a été démontré in vitro et in planta. Le filtrat de culture pur et dilué à 25 et 50 % réduit jusqu’à 95% les symptômes de la maladie. Ensuite, l’iturine produite par Bacillus spp. III1 a été identifiée comme étant de la mojavensine. Les conditions environnementales optimales de production de la mojavensine (pH, température et aération) ont été déterminées en utilisant la méthode des plans d’expériences. Finalement, une optimisation des conditions environnementales de la pumilacidine, lipopeptide produit par Bacillus pumilus I2 a été réalisée<br>The aim of this thesis was to screen bacteria isolated from the rhizosphere of the date palm tree for their ability to inhibit phytopathogenic fungi. Screening for antifungal activity was performed on twenty-eight isolates. Five antagonistic isolates were selected and identified as members of Bacillus genera. The five antagonistic Bacillus isolated showed tolerance to abiotic stresses (high temperature, salinity, drought). The presence of biosynthetic genes encoding lipopeptides was investigated by PCR and lipopeptide production was confirmed by MALDI-ToF mass spectrometry. The antagonistic Bacillus spp. III1 strain that produced a high diversity of lipopeptides belonging to surfactin, fengycin and iturin families and that showed the strongest antifungal activity was evaluated for biocontrol of Septoria tritici blotch, one of the most important foliar pathogens of wheat. The inhibitory effect of the culture filtrate of the strain III1 on growth and germination of Zymoseptoria tritici, the causal agent of wheat disease, was demonstrated in vitro and in planta. The pure culture filtrate and diluted to 50% and 25 % reduced up to 95% the symptoms of the disease. Then iturin produced by Bacillus spp. III1 was identified as mojavensine. The optimum environmental conditions for producing mojavensin (pH, temperature and ventilation) were determined using the method of design of experiments. Finally, optimization of the environmental conditions of the pumilacidin, lipopeptide produced by Bacillus pumilus I2 was performed
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Kramer, Bastian. "Identifizierung und Charakterisierung neuer Pathogenitätsfaktoren in einem MAPK-Signalweg des weizenpathogenen Pilzes Mycosphaerella graminicola." Duisburg Köln WiKu, 2009. http://d-nb.info/992415756/04.
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Gadoury, Hélène. "Evaluation of Septoria galeopsidis Westd. as a bioherbicide for hemp-nettle (Galeopsis tetrahit L.)." Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61896.
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Bamford, Victoria A. "X-ray crystallographic studies of extracellular proteins from Septoria lycopersici : a widespread tomato pathogen." Thesis, University of East Anglia, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302060.
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Lee, Jack Alexander. "The use of virus induced gene silencing to investigate Septoria leaf blotch in wheat." Thesis, Durham University, 2016. http://etheses.dur.ac.uk/11465/.
Texte intégralRésumé :
Septoria leaf blotch, caused by the fungal pathogen Zymoseptoria tritici, is one of the most damaging diseases of wheat (Triticum aestivum), a crop plant of significant worldwide importance. Using the system of Virus-Induced Gene Silencing, to create transient knockdowns of target genes, a novel wheat gene, TaR1, was identified as playing a key role in the host response to this pathogen. Silencing this gene leads to the earlier onset of disease symptoms, but reduced reproduction of the causal pathogen. Sequence analysis, confocal microscopy and protein-protein interaction assays were used to determine that the protein TaR1 localises the nucleus, where its function involves the binding of histones. Precisely, TaR1 is able to bind the Histone 3 subunit, specifically methylated on Lysine 4. Through this action, the host defence response is delayed, and successful pathogen colonisation is promoted. It is hypothesised that this is an example of the pathogen ‘hi-jacking’ TaR1 from its original function, in order to complete its lifecycle.
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Ors, Marie-Eva. "Importance du cultivar dans la résistance induite par des stimulateurs de défense des plantes vis-à-vis de mycosphaerella graminicola, agent responsable de la septoriose du blé." Thesis, Littoral, 2015. http://www.theses.fr/2015DUNK0416.
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L'utilisation de molécules stimulatrices de défense des plantes (SDP), également appelées inducteurs de résistance, constitute une alternative possible aux traitements fongicides conventionnels pour contrôler les maladies dues aux chanpignons phytopathogènes. Dans cette étude, nous avons mis en évidence que trois produits à caractère SDP (FSOV2, FSOV7 et FSOV10) protègent le blé (Triticum aestivum L.) contre la septoriose (Mycosphaerella graminicola, anamorphe Zymoseptoria tritici) lorsqu'ils sont utilisés de façon préventive, mais cette protection dépend fortement du cultivar considéré. Les cultivars Alixan, Premio et Altigo testés ici présentaient au départ des niveaux de résistance distincts à la septoriose. Les protections obtenues ne sont pas liées à un effet direct sur la germination des spores du champignon, mais à l'induction des mécanismes de défense chez le blé qui réduisent la nécrose foliaire et la sporulation du champignon. Ainsi, l'observation des différents stades du processus infectieux de M. graminicola en microscopie et le dosage des activités enzymatiques fongiques de dégradation des parois (CWDE) in planta révèlent que le niveau de protection induite varie avec le SDP appliqué et avec le cultivar traité. L'expression de neuf gènes impliqués dans différentes voies de défense, suivi par RTqPCR, et les activités enzymatiques peroxydase et phénylalanine ammonia lyase ont été mesurée au cours du temps, depuis le traitement par les SDP jusqu'à 5 jours après infection. Les résultats obtenus montrent, que les mécanismes de défense sont induits différemment en fonction du cultivar et en fonction du SDP appliqué. Ces résultats suggèrent que la réussite au champ des SDP est conditionnée de façon déterminante par le choix du couple SDP-cultivar<br>The use of resistance inducers (RI) is a potential alternative to conventional fungicide treatments against plant fungal diseases. In the present study, we revealed that preventive applications of three RI conferred protection efficacies against M. graminicola, with protection levels varying with the wheat cultivar. Alixan, Premio and Altigo cultivars were previously known to exhibit distinct resistance levels to M. graminicola. The observed protections did not result from a direct effect on spore germination, but were related to the induction of wheat defense mechanisms. The induced resistances reduced foliar necrosis, as well as the sporulation level of the fungus. Microscopic observations of the infection process of M. graminicola and cell wall degrading enzymes (CWDE) activities measured in planta showed that the applied RI as well as the considered treated wheat cultivar influences the impact on the infection process and the protection efficacy. We investigated from the time of treatment until 5 days after inoculation plant peroxidase and phenylalanine ammonia lyase activities and the expression of nine genes involved in distinct defense pathways. Our results indicated that defense mechanisms are differently induced according both to the wheat cultivar and the RI. Therefore, the successful use of RI at the field level strongly depends on the RI-cultivar combination
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Radons, Sidinei Zwick. "Severidade de ocorrência de mancha de septória e produtividade do girassol irrigado." Universidade Federal de Santa Maria, 2010. http://repositorio.ufsm.br/handle/1/5019.
Texte intégralRésumé :
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior<br>This study aimed to evaluate the severity of occurrence of septoria leaf spot in sunflower, its association with meteorological variables and its effect on yield of field
irrigated sunflower. The experiments were conducted in Santa Maria - RS during the 2008 spring season and during the 2009 fall growing season, with sowings in September and in February, respectively. Observations of severity of septoria leaf spot were made throughout the crop cycle, and with a disease forecasting system different times for fungicide applications have been identified. Results show that a sequence of rainy days, with favorable temperatures
to the pathogen, tend to contribute to the development of septoria leaf spot in sunflower. In contrast, when water needed by plants is restored by irrigation, even temperature is favorable to the pathogen, disease development rate is lower than during and within 10 days of rainy periods. There were observed differences in septória leaf spot severity between treatments with and without fungicide application, but were not related to the yield of sunflower achenes. Fungicide application according to the different treatments did not significantly affect achene yield either. Therefore, significant differences in the variables that represent the progression of the disease do not necessarily imply in significant differences in yield.<br>Neste trabalho objetivou-se verificar a severidade de ocorrência de mancha de septória em girassol, sua associação aos elementos meteorológicos e seu efeito na produtividade do
girassol cultivado a campo sob irrigação. Os experimentos foram conduzidos em Santa Maria RS durante a safra de 2008 e safrinha de 2009, com semeaduras em setembro e fevereiro, respectivamente. Foram realizadas observações de severidade de mancha de septória durante todo o ciclo da cultura e, com o auxílio de um sistema de previsão de doenças, foram definidos diferentes momentos para as aplicações de fungicida. Os resultados demonstram
que sequencias de dias chuvosos, com temperatura favorável ao patógeno, tendem a contribuir para o desenvolvimento da mancha de septória no girassol. Em compensação, quando a água necessária às plantas é reposta por meio de irrigações, mesmo que a temperatura seja favorável ao patógeno, a taxa de desenvolvimento da doença é menor do que durante e até 10 dias após períodos chuvosos. Foram verificadas diferenças de severidade observada de mancha de septória entre tratamentos com e sem aplicação de fungicida, mas essas não
apresentaram relação significativa com a produtividade de aquênios do girassol. A aplicação de fungicida, conforme os diferentes tratamentos, também não apresentou associação
significativa com a produção de aquênios. Portanto, diferenças significativas nas variáveis que representam a progressão da doença não implicam necessariamente em diferenças significativas de produtividade.
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Bates, Marlin A. "Efficacy of compost tea on Septoria leaf spot of tomato in field and greenhouse studies." Thesis, Manhattan, Kan. : Kansas State University, 2007. http://hdl.handle.net/2097/499.
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Chartrain, Laëtitia. "Genes for isolate-specific and partial resistance to Septoria tritici blotch (Mycosphaerella graminicola) in wheat." Thesis, University of East Anglia, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.405687.
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Cruz, Christian D. "Impact Of Foliar Diseases On Soybean In Ohio: Frogeye Leaf Spot And Septoria Brown Spot." Columbus, Ohio : Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1228070831.
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Guimarães, Letícia Simone. "Mancha parda (Septoria glycines Hemmi) da soja (Glycine max L.) : aspectos etiológicos e de controle." reponame:Repositório Institucional da UnB, 2008. http://repositorio.unb.br/handle/10482/3796.
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Tese (doutorado)—Universidade de Brasília, Instituto de Ciências Biológicas, Departamento de Fitopatologia, 2008.<br>Submitted by Thaíza da Silva Santos (thaiza28@hotmail.com) on 2010-02-27T04:02:36Z
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Previous issue date: 2008-04-17<br>A soja (Glycine max), percentualmente, foi a cultura que mais cresceu nos últimos anos. A produção (26%) brasileira é a segunda maior do mundo, ficando atrás somente dos EUA (37%). O potencial produtivo da soja poderia ser maior se não fosse os danos causados pelas doenças nesta cultura. A mancha parda ou septoriose (Septoria glycines), uma das principais “doenças de final de ciclo”, tem provocado danos em lavouras comerciais de diversas regiões brasileiras, podendo reduzir o rendimento em mais de 30%. A busca para encontrar cultivares de soja resistentes a S. glycines vem de três a quatro décadas atrás, porém até os dias atuais ainda não foram encontradas cultivares com resistência satisfatória à doença. Assim sendo, o controle desta doença é baseado na aplicação de fungicidas. Diante da importância da cultura e da doença os objetivos deste trabalho foram: (a) avaliar em campo a reação de genótipos convencionais e transgênicos à doença e o efeito da época e do local de plantio; (b) avaliar o efeito de fungicidas no controle da mancha parda. Os experimentos foram conduzidos no campo (Cristalina, GO) durante as safras 2004/2005 e 2005/2006 e em casa de vegetação (Brasília, DF) e laboratório nos anos de 2006 a 2008. Em uma primeira etapa foram testados 16 genótipos, três épocas de semeadura e quatro tratamentos com fungicidas. Os resultados indicaram que dos genótipos avaliados, a menor quantidade da doença e maior produtividade foram apresentados pelos genótipos Msoy8411 e GT01-308, e conforme foi se atrasando o plantio, de outubro para dezembro, a intendidade da mancha parda foi aumentado. Na segunda etapa do trabalho avaliou-se a reação de 92 genótipos de soja à mancha parda, entre estes genótipos existiam cultivares de ciclo precoce, médio e tardio. Entre os genótipos avaliados observou-se existir uma variação nos níveis de susceptibilidade, 43,4% apresentaram menores valores de severidade quando comparados ao genótipo padrão (Msoy8001). Na análise da severidade da doença, AACPD e produtividade em relação aos ciclos das culturas, observou-se que as cultivares precoces apresentaram maiores valores de severidade e AACPD e menores valores de produtividade. Em uma terceira etapa do trabalho avaliou-se a reação à mancha parda de genótipos de soja transgênica e convencional. Não foram observadas diferenças de severidade de doença entre soja transgênica e convencional. Houve variação na susceptibilidade à doença entre os genótipos, porém não houve nenhum com resistência. Na quarta etapa do estudo analisou-se a resposta de genótipos de soja à mancha parda em diferentes localidades. Neste experimento foram semeados 58 genótipos em quatro localidades (Cristalina, Orizona, Morrinhos e Piracanjuba/ GO). Dos 58 genótipos avaliados, 31 apresentaram severidade semelhante ao padrão Msoy8001, considerado moderadamente suscetível. Os genótipos restantes mostraram maiores valores de severidade. Em todos os locais avaliados observaram-se diferenças entre produtividade. Durante a terceira etapa do trabalho, subdividiu-se o estudo em dois: (a) o primeiro trata da avaliação de fungicidas e da época de aplicação sobre a mancha parda da soja, e o segundo; (b) estudou-se a resposta do uso de fungicidas (tetraconazol) e fitorreguladores (ácido índolbutírico 0,005%, cinetina 0,009% e ácido giberélíco, como GA3 0,005%) na intensidade da mancha parda. Na primeira sub-etapa (a), conclui-se que dos dez produtos testados, Chlorotalonil (500g i.a./L) + Tetraconazole (20g i.a./L) na dose de 1,75 L/ha foi eficiente na redução da mancha parda. Na sub-etapa (b) não houve redução na doença, nem incremento na produtividade da soja devido aos tratamentos. Finalmente, um estudo foi realizado com a finalidade de padronizar o meio de cultura e temperatura para a obtenção de inoculo de S. glycines. Testaram-se cinco meios de cultura e três temperaturas de incubação. O meio mais adequado para a produção de conídios (1,53 x 107conídios / ml) foi o de extrato de folha de soja ágar (Folha de soja 200g; sacarose 10g; ágar 15g; 1l água destilada) a 20°C de incubação. Em seguida procurou-se definir um protocolo para o uso do “método da folha destacada” para avaliar sintomas da mancha parda. Após a análise dos resultados dos experimentos, verificou-se que a técnica de pincelamento de conídios foi mais prática do que a da pulverização. Concentrações acima de 1 x 105 conídios/ml foram eficientes na produção de sintomas. O estádio foliar mais adequado para inoculação foi o V2. Todas as temperaturas (20 a 30°C) incitaram a manifestação dos sintomas e não foram observadas diferenças de severidade da doença entre inoculações feitas na face adaxial ou abaxial das folhas.
_______________________________________________________________________________ ABSTRACT<br>In recent years, soybean (Glycine max) had one of the greatest production increase among the cultivated crops. Brazil is the second largest soybean world producer (26%), staying only behind of the United States of America (37%). The incidence of diseases reduces the potential production of soybean. The brown spot (Septoria glycines) is one of the diseases that cause reduction on soybean yield. The Brazil’s soybean yield reduction due to brown spot might reach losses higher than 30%. From the last three to four decades, the search for brown spot resistant soybean cultivars was not satisfactorily successful. Therefore, the major brown spot control method is the application of fungicides. Based on above information the objectives of this study were: (a) assess the reaction to brown spot of conventional and transgenic soybean on different time of and different planting locations, and; (b) evaluate the effect of fungicide application brown spot. The experiments were performed in the field (Cristalina, GO, Brazil) during the growing seasons of 2004/2005 and 2005/2006, and in greenhouse (Brasília, DF, Brazil) and laboratory in 2006 to 2008. In the first part of the study were tested 16 soybean genotypes, three planting times, and four different treatments with fungicides. The results indicated that Msoy8411 and GT01-308 genotypes presented lowest amount of brown spot and the highest yield. In addition, the December planting time favored the increase of disease (severity and incidence) if compared to October and November planting time. In the second part of the study a brown spot reaction evaluation of 92 soybean genotypes with contrasting growing response was conducted. Among these genotypes, 43.4% of then presented lower disease ratings than the traditional standard genotype (Msoy8001). The cultivars with smaller growing cycles presented higher disease severity, lower yield than the ones with longer cycles. In the third part of the study is the reaction to brown spot of transgenic and conventional soybean genotypes was evaluated. There were no significant disease differences between transgenic and conventional soybeans. There were degrees of susceptibility to brown spot among the genotypes, but no resistant genotypes. In the fourth stage of the study, 58 genotypes were planted in four localities (Cristalina, Orizona, Morrinhos, and Piracanjuba, GO, Brazil). From these genotypes, 31 showed similar disease severity to the standard genotype (Msoy8001) considered moderately susceptible. The remaining genotypes showed higher values of severity. In all four evaluated places there were differences on genotype yield. In addition, during the third part stage this study, two evaluations were made: (a) evaluation of different fungicides and timing of application on brown spot, and; (b) evaluation of fungicide (tetraconazole) and growth regulators (IBA 0005% 0009% kinetin and gibberellic acid, GA3 as 0005%) on brown spot intensity. From these tests, Chlorotalonil (500g ai / L) + tetraconazole (20g ai / L) at a dose of 1.75 L / ha was effective to reduce brown spot. In the second sub-step (b) no differences on soybean disease and yield due to treatments. Finally, a study was carried out to standardize a culture media and temperature to satisfactorally produce S. glycines conidia. Five culture media and three incubation temperatures were tested.The media considered more suitable for the production of conidia (1.53 x 107 conidia / ml) was the extract of soybean leaves agar (Soybean Leaf 200g, sucrose 10g, agar 15g, 1l distilled water) at 20° C of incubation. Also, a protocol to induce brown spot symptoms, using the "method of detached leaf”, was studie After seven experiments were performed the analysis of the results showed: (a) the technique of brushing conidia suspension on leaves was more practical than spraying. Concentrations above 1 x 105 conidia / ml were effective in producing symptoms. The best leaf phonological stage for inoculation was V2. All tested (20 to 30°C) temperatures that were used to incubate the inoculated leaves showed symptoms, and no disease differences were observed between inoculations made on above and under side of leaves.
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Mudita, I. Wayan. "Production of Conidia, selection of inoculum density, and timing the first fungicide application to manage Septoria blight of celery." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61038.
Texte intégralRésumé :
Septoria blight of celery (Apium graveolens var. dulce), induced by Septoria apiicola Speg., is a destructive disease that requires fungicide applications for its management. A reliable method of inoculum production was established. Best sporulation was obtained on celery agar (CA) at a predicted optimum temperature of 22.4$ sp circ$C. A moderate inoculum density within a range of 17-35 conidia/cm$ sp2$ of leaf surface provided non-coalescing lesions necessary for rapid enumeration. Initial blight incidence thresholds of about 0.6 and 0.5% to time the first fungicide application were established based on the proportion of maximum plant weight equivalent to the cost of one fungicide application calculated plant weight and petiole number per plant, respectively, in the summers of 1990 and 1991. The IBI levels of 0 and 2% to time the first fungicide application provided non-significant results in terms of the final amount of blight and yield. (Abstract shortened by UMI.)
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Lovering, Nancy. "Collection and evaluation of bacteria for the biological control of late blight of celery : (Septoria apiicola Speg.)." Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=23914.
Texte intégralRésumé :
Late blight, caused by Septoria apiicola Speg., is the most important disease affecting celery in Quebec. Biological control was investigated as an alternative to conventional chemical control of late blight. Two hundred and four bacterial isolates were collected from celery leaves, and muck and mineral soils of celery fields in south-western Quebec. Two experiments were conducted to screen the bacteria for antagonism toward Septoria apiicola: one on agar to test for inhibition of pycnidial formation, and the other on leaf disks to test for inhibition of germination of conidia. From these two experiments, 18 isolates were selected that prevented pycnidial formation in an inhibition zone $ ge$1.0 cm wide and reduced germination to below 30% of the control. These isolates were re-evaluated for inhibition of germination on leaf disks. A bacterial suspension (10$ sp7$ cells/ml) was incubated on leaf disks for 24 hours before a suspension of S. apiicola conidia (150,000 spores/ml) was applied, and the disks were incubated for 25 hours. Four isolates reduced germination to $ le$19% of the control. These isolates were tested on plants in a greenhouse. None of the isolates was able to reduce the number of late blight lesions compared to the control.
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Brogin, Rodrigo Luis. "Mapeamento de genes de resistência à ferrugem e de QTLs envolvidos na resistência à septoriose em soja." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/11/11137/tde-18112005-142854/.
Texte intégralRésumé :
A ocorrência de doenças em soja tem aumentado nos últimos anos, provocando grandes perdas em plantios comerciais e exigindo respostas rápidas da pesquisa para desenvolvimento e aplicação de técnicas de controle. Mais de 40 doenças afetam a cultura da soja em todo o mundo e dentre elas estão a ferrugem asiática (Phakopsora pachyrhizi Sydow) e a septoriose ou mancha parda (Septoria glycines Hemmi). Estas doenças estão disseminadas em praticamente todas as regiões produtoras de soja do Brasil. Os objetivos desse trabalho foram mapear o gene que confere resistência a P. pachyrhizi presente na cultivar de soja FT-2 e QTLs envolvidos na resistência a S. glycines, utilizando uma população de plantas F2 derivada do cruzamento entre as cultivares FT-2 (resistente) e Davis (suscetível). Marcadores microssatélites foram testados nos genitores, sendo os polimórficos utilizados para genotipar as plantas da geração F2. Progênies F3:2 e F4:2 foram obtidas e avaliadas para reação às doenças. Para a ferrugem da soja foram detectados cinco marcadores associados ao caráter, sendo que dois deles (Satt079 e Satt307) flanqueiam o gene dominante de resistência, que foi mapeado no grupo de ligação C2 da soja. Uma eficiência de seleção de 100% foi obtida com o uso simultâneo destes dois últimos marcadores, indicando que os mesmos podem ser ferramentas úteis para a seleção assistida de genótipos homozigóticos resistentes. Para a mancha parda, análises de regressão e de variância foram realizadas para identificar associações significativas entre marcadores e QTLs devido a efeitos aditivos e não aditivos do caráter. Foi realizado, também, o mapeamento por intervalo dos QTLs. As análises de regressão detectaram maior número de marcadores ligados a QTLs do que o mapeamento por intervalo; houve concordância entre os resultados dos dois métodos em apenas um caso, no qual o marcador Satt277, pertencente ao grupo de ligação C2, foi relacionado significativamente ao caráter.<br>The occurrence of soybean diseases that causes large yield losses in commercial fields has increased in recent years forcing research to face the challenge of providing quick responses to develop control techniques. More than 40 diseases affect soybeans worldwide, among them the Asian rust (Phakopsora pachyrhizi Sydow) and brown spot (Septoria glycines Hemmi). These diseases are spread in practically all Brazilian soybean cropping areas. The objectives of this work was to map the resistance gene to P. pachyrhizi and the QTLs involved in the resistance to S. glycines in the soybean cultivar FT-2, using an F2 plant population derived from the cross between FT-2 (resistant) and Davis (susceptible). SSR markers were tested in the parents and those showing polymorphism were used to screen plants of the F2 generation. F3:2 and F4:2 progenies were evaluated for disease reaction. Five markers associated to soybean rust resistance were detected and two (Satt079 and Satt307) are flanking a dominant resistance gene that was mapped in the C2 soybean linkage group. An efficiency of 100% was obtained with the simultaneous use of those markers for selection, which indicated that they could be useful in marker-assisted selection of resistant homozygous genotypes. For brown spot resistance, regression analyses and ANOVAs were performed to identify significant associations between markers and resistance QTLs showing additive and non-additive effects. The interval mapping of the QTLs was also performed. The regression analyses detected more markers linked to QTLs than the interval analyses. Only the Satt277 marker (soybean linkage group C2) was significantly associated to the trait by both detection methods.
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Judge, Christopher. "Disease escape in relation to a trade off between Septoria tritici blotch and yield of wheat." Thesis, University of East Anglia, 2015. https://ueaeprints.uea.ac.uk/59397/.
Texte intégralRésumé :
Zymoseptoria tritici, the fungus that causes Septoria tritici blotch (STB) of wheat, is spread by splash borne transfer from the base of the plant to the flag leaf. This project is on a potential new source of resistance to STB discovered on chromosome 6A using association mapping (Arraiano & Brown 2016). Near isogenic lines generated for this region show no significant differences in STB symptoms when leaves are directly inoculated with Z. tritici. However, trials that are naturally infected or inoculated at the base of the plant show clear differences in their level of STB. This indicated that this region contains genes that cause differences in disease escape. The fact that the same marker Psp3071 is associated with yield traits (Snape et al, 2007) led to the hypothesis that the region may control a physiological trait that improves yield at the cost of aiding spore transmission. Candidate physiological traits, that could influence disease escape, have been tested in the 6A NILs including plant height, leaf area and senescence. The trait that fits with the pattern of the disease results best is leaf emergence, with later emerging leaves getting more STB. However, the effect of the 6A alleles on disease escape may be caused by multiple traits. Recombinant lines generated for the region have reduced the interval that contains the yield traits, though it is still unclear if the disease escape and yield effects are connected by linkage or pleiotropy.
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Peralta, Federico José Matías. "Efecto del estrés hídrico en tallos de álamos y discos de hojas colonizados por Septoria musiva." Bachelor's thesis, Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias, 2015. http://bdigital.uncu.edu.ar/6835.
Texte intégralRésumé :
En Mendoza, el cultivo del álamo representa la actividad forestal de mayor importancia dentro de los bosques cultivados bajo riego. La superficie cultivada con estos se estima que alcanza aproximadamente unas 16.000 ha incluyendo las plantaciones en macizo y las plantaciones en línea o cortinas. El microorganismo patógeno Septoria musiva es el agente causal de una de las enfermedades con mayor influencia en la cantidad y calidad de la madera producida por los álamos, el cual se manifiesta produciendo manchas foliares y cancros en troncos y ramas. El sitio y las condiciones meteorológicas adversas, y así como otros agentes de estrés, tales como plagas de insectos, pueden aumentar la incidencia y severidad de la infección por uno o más patógenos. Durante las últimas décadas, los daños causados por estrés hídrico en álamos se están incrementando en varios países, produciendo decaimiento de árboles, ataque de parásitos oportunistas y muerte de plantas. Considerando la importancia del cultivo de álamos en Mendoza y a nivel nacional, sumado al hecho que Septoria musiva es un patógeno endémico en la región provocando grandes pérdidas económicas, el objetivo de este trabajo fue determinar el efecto del estrés hídrico en la colonización de tallos y hojas de clones de Populus spp. inoculados por Septoria musiva. Los clones de álamo Harvard y Conti-12 fueron sometidos a tres niveles de estrés hídrico en invernadero (lámina de reposición del 90, 70, 50 % del agua disponible). Luego la mitad de las plantas de cada clon fueron inoculadas con un aislado de Septoria musiva y la otra mitad fueron utilizadas como testigos. La respuesta al patógeno se midió 95 días después, como longitud promedio de cancro y porcentaje promedio del perímetro del tallo afectado por la lesión. Los valores para estas variables fueron mayores cuando aumento el nivel de estrés hídrico para ambos clones. También se llevó a cabo un ensayo de disco de hojas, utilizando hojas de las plantas sometidas a los diferentes niveles de estrés. Estos fueron colocados en cajas de Petri e inoculados con Septoria musiva y sus respectivos testigos con agua estéril. Los clones mostraron una respuesta diferencial al estrés hídrico. En Harvard el porcentaje promedio de área necrótica en hojas aumentó cuando el agua disponible para la planta fue mayor, en cambio en el Clon Conti-12 sucedió lo contrario. Esta investigación aporta información valiosa para el manejo de la salud de las plantaciones forestales de álamo. La información generada en este trabajo resulta de máxima utilidad para los productores, los cuales deberían tomar los recaudos necesarios en el manejo del agua en las plantaciones de modo de disminuir el efecto del estrés hídrico. Situación ésta que puede provocar aumento de la susceptibilidad a la enfermedad por parte de las plantas. Este conocimiento permitirá a los productores maximizar los beneficios del cultivo y reducir al mínimo el riesgo a cancrosis.<br>Fil: Peralta, Federico José Matías. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias.
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VÁZQUEZ, MORENO CARMEN. "MANEJO DE ENFERMEDADES FOLIARES CON Trichoderma spp. Y Bacillus subtilis EN CEMPASÚCHIL (Tagetes erecta) DEL VALLE DE TOLUCA." Tesis de Licenciatura, Universidad Autónoma del Estado de México, 2016. http://hdl.handle.net/20.500.11799/65609.
Texte intégralRésumé :
México es centro de origen del cempasúchil (Tagetes erecta) y por ello también es reconocido como uno de los principales productores de esta especie a nivel mundial. A nivel nacional Puebla es el principal estado productor de cempasúchil, en el Estado de México se reportan un promedio de 98 hectáreas sembradas. El cempasúchil es una especie que es utilizada principalmente en las festividades de día de muertos, en la industria es utilizado para la elaboración de colorante, harinas, dulces, también como alimento para aves y aumentar el color de la yema del huevo, etc.; En la agricultura es una especie apreciada por su capacidad de repeler plagas (insectos, hongos, nematodos, etc.). Sin embargo a pesar de esta característica también es atacada por insectos, hongos, nematodos y fitoplasmas, capaces de reducir de manera significativa los rendimientos. Actualmente en la agricultura, se busca el control de las plagas en general, cuidando el medio ambiente, es por ello que se buscan alternativas como por ejemplo el control biológico. El presente trabajo tuvo por objeto el controlar enfermedades foliares con Trichoderma sp. y Bacillus sp. ocasionadas por Plasmopara sp., Septoria sp. y Alternaria sp. en cultivo cempasúchil en el Valle de Toluca, bajo condiciones de cielo abierto, se establecieron fechas de aspersión siguiendo un patrón de programas y realizando muestreos en un intervalo de diez a quince días, para evaluar la variable severidad media ponderada, basándonos en escalas diagramáticas de seis clases para cada uno de estos patógenos. Los resultados indicaron que Bacillus sp. y Trichoderma sp. tienen la capacidad de reducir la severidad ocasionada por Plasmopara sp. y Alternaria sp., Bacillus sp. tiene potencial para ser utilizado en el control de Septoria sp.
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Kososki, Rafaela Mariana. "Diversidade genética e reação de genótipos de maracujazeiro a septoriose, verrugose e mancha oleosa em casa de vegetação." reponame:Repositório Institucional da UnB, 2014. http://repositorio.unb.br/handle/10482/17282.
Texte intégralRésumé :
Tese (doutorado)—Universidade de Brasília, Faculdade de Agronomia e Medicina Veterinária, Programa de Pós-Graduação em Agronomia, 2014.<br>Submitted by Larissa Stefane Vieira Rodrigues (larissarodrigues@bce.unb.br) on 2014-12-08T17:59:56Z
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2014_RafaelaMarianaKososki.pdf: 3328066 bytes, checksum: 1f13cd84a1808e52d84d2769176a578a (MD5)<br>O cultivo do maracujazeiro (Passiflora edulis Sims.) em escala comercial teve inicio no começo da década de 1970. O Brasil é o maior produtor e consumidor mundial de maracujá, sendo a Bahia o maior produtor nacional. Nos últimos anos tem-se observado uma redução na produtividade, o que se deve, principalmente, à ocorrência de doenças nessa cultura. Entre tais doenças, destaca-se a mancha oleosa ou queima bacteriana (Xanthomonas axonopodis pv. passiflorae), a verrugose (Cladosporium spp.) e a morte precoce (causada por um conjunto de fitopatógenos). Em programas de melhoramento, a estimativa de parâmetros genéticos é importante na indicação de recursos a serem utilizados e também no ganho de seleção esperado. Oito experimentos com 24 genótipos cada, de maracujazeiro-azedo, foram avaliadas aos 7, 14, 21, 28 e 35 dias, quanto à resistência a Septoria passiflorae e Cladosporium herbarum em condições de casa de vegetação na Universidade de Brasília. O delineamento foi o de blocos casualizados com quatro repetições, 24 tratamentos (genótipos) e seis plantas por parcela. Já para bacteriose, foram realizados 2 ensaios experimentais na Estação Experimental de Biologia - EEB da Universidade de Brasília, no Distrito Federal, em condições de casa de vegetação (26 a 32º C). O delineamento foi em blocos casualisados com parcela subdividida, parcela (épocas), subparcela de 24 genótipos com 4 repetições e 6 plantas por parcela. Ensaio 1 (clorose e necrose), isolado RIO CLARO e Ensaio 2 (clorose e necrose), isolado LIMEIRA, com 24 genótipos cada. Na diversidade genética foram avaliados 24 genótipos de maracujazeiro-azedo mais resistentes, às principais doenças avaliadas em casa de vegetação (EEB). O trabalho laboratorial foi realizado no Laboratório de Genética e Biologia Molecular - Embrapa Cerrados com a extração de DNA pelo método do CTAB com algumas modificações. O objetivo do presente trabalho foi o de avaliar a reação de genótipos de maracujazeiro azedo a septoriose (S. passiflorae), a verrugose (C. herbarum) e a mancha oleosa (X. axonopodis pv. passiflorae) em de casa de vegetação; estudar a variabilidade genética das genótipos de maracujazeiro utilizadas em casa de vegetação com base em marcadores moleculares de DNA e identificar genótipos de maracujazeiro com potencial utilização no melhoramento genético. Assim, verificou-se como resistentes à septoriose: AR 01 PLANTA 1, AR 02 PLANTA 1, ECL 7 PLANTA 3, MAR20#34, MAR20#15 PLANTA 2, MAR20#44, MAR20#15 PLANTA 3, ECL 7 PLANTA 1, MAR20#12 PLANTA 1, EC-3-0 PLANTA 10 , MAR20#34 PLANTA 6, MAR20#21 PLANTA 2, MAR20#23 PLANTA 2, AR 02 PLANTA 2, ECRAM PLANTA 3, GIGANTE AMARELO PLANTA 1, MAR20#10 PLANTA 2. Não se verificou materiais resistentes à verrugose. Verificou-se como material resistente à bacteriose: Passiflora nitida. As distâncias genéticas entre os 24 acessos de maracujá variaram de 0,021 a 0,303 entre os genótipos de maracujá. Com base na análise de agrupamento, foram encontrados diferentes grupos de similaridade e verificada a variabilidade genética entre os genótipos de maracujá (Passiflora sp.) trabalhadas. Assim, o desenvolvimento de cultivares resistentes à doenças é importante para as culturas agrícolas, pois teremos a redução de custos de produção, maior segurança de trabalhadores agrícolas e consumidores, melhor qualidade mercadológica, maior preservação do ambiente e maior sustentabilidade do agronegócio. E no caso de P. edulis, tal estratégia é de fundamental importância tendo em vista a alta suscetibilidade das atuais variedades comerciais às principais doenças. A busca e a caracterização de fontes de resistência a doenças para a implementação e o sucesso de programas de melhoramento. _________________________________________________________________________________ ABSTRACT<br>The cultivation of passionfruit (Passiflora edulis Sims.) on a commercial scale began in the early 1970s. Brazil is the largest producer and consumer of passionfruit, and Bahia is the largest producing state. In recent years it has been observed a reduction in productivity, which is due mainly to the occurrence of diseases that culture. Among these diseases, there is the bacterial spot or blight (Xanthomonas axonopodis pv. passiflorae), scab (Cladosporium spp.) and premature death (caused by a number of pathogens). In breeding programs, the estimation of genetic parameters is important in directing resources to be used and also to predict the expected selection gain. Eight experiments with 24 genotypes each of passion fruit were evaluated at 7, 14, 21, 28 and 35 days for resistance to Septoria passiflorae and Cladosporium herbarum conditions in a greenhouse at the University of Brasilia. The experimental design was randomized with four replications of 24 treatments (genotypes) and six plants per plot blocks. As for disease, the two experimental trials were conducted at the Experimental Biology Station - BSE from the University of Brasilia, Federal District, under greenhouse conditions (26 to 32º C). The design was randomized blocks with plot subdivided plot (times), subplot 24 genotypes with 4 replications and 6 plants per plot. Test 1 (chlorosis and necrosis), isolated RIO CLARO and Test 2 (chlorosis and necrosis), isolated LIMEIRA with 24 genotypes each. Genetic diversity in 24 genotypes more resistant passionfruit were evaluated, the major diseases evaluated in a greenhouse at the Experimental Biology Station - BSE from the University of Brasilia. The laboratory work was conducted at the Laboratory of Genetics and Molecular Biology - EMBRAPA Cerrado with DNA extraction by the CTAB method with some modifications. The aim of this study was to evaluate the reaction of genotypes of sour passionfruit to septoria spot (S. passiflorae), scab (C. herbarum) and oily spot (X. axonopodis pv. passiflorae) in a greenhouse; study the genetic variability of genotypes of passion used in greenhouse based on DNA molecular markers and identify genotypes of passion with potential use in breeding. Thus, the following genotypes were considered resistant to the Septoria spot: AR 01 PLANTA 1, AR 02 PLANTA 1, ECL 7 PLANTA 3, MAR20#34, MAR20#15 PLANTA 2, MAR20#44, MAR20#15 PLANTA 3, ECL 7 PLANTA 1, MAR20#12 PLANTA 1, EC-3-0 PLANTA 10 , MAR20#34 PLANTA 6, MAR20#21 PLANTA 2, MAR20#23 PLANTA 2, AR 02 PLANTA 2, ECRAM PLANTA 3, GIGANTE AMARELO PLANTA 1, MAR20#10 PLANTA 2. There was no scab-resistant materials. The only material considered resistant to the bacterial blight was Passiflora nitida. The genetic distances between the 24 accessions of passion ranged from 0.021 to 0.303 between genotypes passion fruit. Based on cluster analysis, different groups of similarity showed the genetic variability among the genotypes of passionfruit. Thus, the development of disease resistant cultivars is important for crops, because we have to reduce production costs, greater safety of agricultural workers and consumers, marketing better quality, greater preservation of the environment and increased sustainability of agribusiness. And in the case of P. edulis, such a strategy is of fundamental importance due to the susceptibility of current commercial varieties to major diseases. The search and characterization of sources of disease resistance to the implementation and success of breeding programs.