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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
131

Development and use of introgression populations for the detection of QTL related to important agronomic traits in eggplant

Mangino, Giulio 28 October 2022 (has links)
Tesis por compendio / [ES] La berenjena (Solanum melongena L.) es uno de los cultivos comerciales de hortalizas solanáceas más importantes que se cultiva ampliamente en Asia y la región del Mediterráneo. A pesar de su importancia económica, la disponibilidad de poblaciones experimentales y herramientas genómicas para el mejoramiento es aún muy limitada en comparación con otros cultivos importantes. Debido a la alteración progresiva del ecosistema global por el cambio climático, las plantas están constantemente expuestas a condiciones ambientales estresantes que impactan negativamente en su productividad. El cuello de botella genético ocurrido durante la domesticación de la berenjena, que limita la disponibilidad de recursos genéticos para su mejoramiento genético, hace que este cultivo sea extremadamente vulnerable al cambio climático, por lo que se requieren nuevas estrategias para reducir su erosión genética. En este contexto, los parientes silvestres de los cultivos (CWRs) han demostrado ser un recurso genético válido para la mejora vegetal, ya que su uso permite ampliar la diversidad genética de los cultivos y, en paralelo, desarrollar variedades mejoradas adaptadas al cambio climático. Para lograr este objetivo, en esta tesis doctoral informamos sobre el desarrollo y la evaluación de materiales avanzados de berenjena obtenidos mediante el uso de parientes silvestres. En el primer capítulo, realizamos una evaluación fenotípica en dos ambientes de un conjunto de 16 ILs de berenjena con introgresión de S. incanum, un pariente silvestre. Se evaluaron diecisiete caracteres agronómicos para comparar el rendimiento de las ILs con el parental recurrente e identificar QTLs para los caracteres investigados. Encontramos diferencias morfológicas significativas entre los parentales, y el híbrido resultó heterótico para los caracteres de vigor. A pesar de que la interacción entre genotipo y ambiente (G x E) resultó significativa para la mayoría de los caracteres, en general las ILs mostraron pocas diferencias fenotípicas con el progenitor receptor, incluso en presencia de grandes fragmentos de introgresión del progenitor silvestre. Se encontraron valores de heredabilidad bajos a moderados para los caracteres agronómicos. En total, detectamos diez QTLs estables, dos de los cuales estaban relacionados con caracteres de planta y cuatro para caracteres de flor y fruto. En general, las introgresiones de S. incanum mejoraron los valores medios de la mayoría de los caracteres de planta y flor, y disminuyeron el de los caracteres de fruto. Para tres QTLs relacionados con la longitud del pedicelo del fruto y con el peso del fruto, encontramos evidencia de sintenia con otros QTLs identificados previamente en poblaciones de berenjena. Siete QTLs eran nuevos, de los cuales cuatro relacionados con la altura de la planta, con la espinosidad del cáliz de la flor y con la longitud del pedicelo del fruto no colocalizaron con ningún QTL previamente identificado en las poblaciones de berenjena, y tres relacionados con el diámetro del tallo, con la longitud del pedúnculo y del estigma, fueron los primeros identificados en berenjena para estos caracteres. En el segundo capítulo, el conjunto de IL de berenjena con introgresiones de S. incanum se evaluó para la forma del fruto en dos ambientes. Específicamente, realizamos un fenotipado detallado de los frutos de los parentales, del híbrido y de las ILs utilizando 32 descriptores morfológicos de la herramienta fenómica Tomato Analyzer. Se encontraron grandes diferencias morfológicas en los frutos de los parentales, y el híbrido presentó valores negativos de heterosis para muchos de los caracteres de forma del fruto, siendo fenotípicamente más cercano al parental S. incanum. Para la mayoría de los descriptores de forma del fruto observamos diferencias significativas entre las ILs y el parental receptor, incluso en presencia de pequeños fragmentos de introgresión del parental silvestre. A pesar de que la contribución del ambiente y la... / [CAT] L'albergínia (Solanum melongena L.) és un dels cultius comercials d'hortalisses solanácees més importants que es cultiva àmpliament a Àsia i la regió del Mediterrani. Malgrat la seua importància econòmica, la disponibilitat de poblacions experimentals i eines genòmiques per al millorament és encara molt limitada en comparació amb altres cultius importants. A causa de l'alteració progressiva de l'ecosistema global pel canvi climàtic, les plantes estan constantment exposades a condicions ambientals estressants que impacten negativament en la seua productivitat. El coll de botella genètic ocorregut durant la domesticació de l'albergínia, que limita la disponibilitat de recursos genètics per al seu millorament genètic, fa que aquest cultiu siga extremadament vulnerable al canvi climàtic, per la qual cosa es requereixen noves estratègies per a reduir la seua erosió genètica. En aquest context, els parents silvestres dels cultius (CWRs) han demostrat ser un recurs genètic vàlid per a la millora vegetal, ja que el seu ús permet ampliar la diversitat genètica dels cultius i, en paral·lel, desenvolupar varietats millorades adaptades al canvi climàtic. Per a aconseguir aquest objectiu, en aquesta tesi doctoral presentem el desenvolupament i l'avaluació de materials avançats d'albergínia obtinguts mitjançant l'ús de parents silvestres. En el primer capítol, realitzem una avaluació fenotípica en dos ambients d'un conjunt de 16 IL d'albergínia amb introgresions de S. incanum, un parent silvestre. Es van puntuar dèsset caràcters agronòmics per a avaluar el rendiment de les ILs en comparació amb el parental recurrent i identificar els QTL per als caràcters investigats. Trobarem diferències morfològiques significatives entre els parentals, i l'híbrid va resultar heteròtic per als caràcters de vigor. A pesar que la interacció entre genotip i ambient (G x E) va resultar significativa per a la majoria dels caràcters, en general les ILs van mostrar poques diferències fenotípiques amb el progenitor receptor, fins i tot en presència de grans fragments d'introgresió del progenitor silvestre. Es van trobar valors de heredabilitat baixos a moderats per als caràcters agronòmics. En total, detectarem deu QTL estables, dos dels quals estaven relacionats a caràcters de planta i quatre per a caràcters de flor i fruit. En general, les introgresions de S. incanum van millorar els valors mitjos de la majoria dels caràcters de planta i flor, i van disminuir el dels caràcters de fruit. Per a tres QTL relacionats amb la longitud del pedicel del fruit i amb el pes del fruit, trobem evidència de sintenia amb altres QTLs identificats prèviament en poblacions d'albergínia. Set QTL eren nous, dels quals quatre estaven relacionats amb l'altura de la planta, amb la espinositat del calze de la flor i amb la llargària del pedicel del fruit no van colocalitzar amb cap QTL prèviament identificat en les poblacions d'albergínia, i tres relacionats amb el diàmetre de la tija, amb la llargària del peduncle i de l'estigma, van ser els primers reportats en albergínia per a aquests caràcters. En el segon capítol, el conjunt de IL d'albergínia amb introgresions de S. incanum es va avaluar per a la forma del fruit en dos ambients. Específicament, realitzarem un fenotipado detallat dels fruits dels parentals, de l'híbrid i de les ILs utilitzant 32 descriptors morfològics de l'eina fenómica Tomato Analyzer. Es van trobar grans diferències morfològiques en els fruits dels parentals, i l'híbrid va presentar valors negatius de heterosis per a molts dels caràcters de forma del fruit, sent fenotípicamente més pròxim al parental S. incanum. Per a la majoria dels descriptors de forma del fruit observarem diferències significatives entre les ILs i el parental recipient, fins i tot en presència de xicotets fragments d'introgresió del parental silvestre. A pesar que la contribució de l'ambient i la interacció G × E van ser significatives per a quasi tots els descriptors, trobem que els seus... / [EN] Eggplant (Solanum melongena L.) is one of the most important commercial solanaceous vegetable crops grown widely in Asia and Mediterranean region. Despite its economic importance, the availability of experimental populations and genomic tools for breeding is still very limited compared to other major crops. Due to the progressive alteration of global ecosystem by climate change, plants are constantly exposed to stressful environmental conditions that impact negatively on their productivity. The genetic bottleneck occurred during eggplant domestication, which limits the availability of genetic resources for its genetic improvement, makes this crop extremely vulnerable to climate change, and, therefore, new strategies are needed for reducing its genetic erosion. In this context, crop wild relatives (CWRs) have demonstrated to be a valid genetic resources for plant breeding, as their use allows to broaden the genetic diversity of the crop and, in parallel, develop improved varieties adapted to climate change. To achieve this objective, in this doctoral thesis we reported on the development and evaluation of eggplant advanced materials obtained by using crop wild relatives. In the first chapter, we have conducted a phenotypic evaluation in two environments of a set of 16 eggplant ILs with introgression from S. incanum, a close wild relative. Seventeen agronomic traits were scored to test the performance of ILs compared to the recurrent parent and identify QTLs for the investigated traits. We found significant morphological differences between parents, and the hybrid was heterotic for vigour related traits. Although significant genotype x environment interaction (G x E) was detected for most traits, the ILs generally exhibited few phenotypic differences with recipient parent, even in the presence of large introgression fragments from the wild parent. Low to moderate heritability values were found for the agronomic traits. In total, we detected ten stable QTLs, two of which were for plant-related traits and four for both flower- and fruit-related traits. In general, S. incanum introgressions improved the performance of most plant- and flower-related traits and decreased that of fruit-related traits. For three QTLs related to fruit pedicel length and fruit weight, we found evidence of synteny to other QTLs previously reported in eggplant populations. Seven QTLs were new, of which four related to plant height, flower calyx prickles, and fruit pedicel length, did not colocalized with any previous identified QTLs in eggplant populations, and three related to stem diameter, peduncle length, and stigma length, were the first reported in eggplant for these traits. In the second chapter, the set of eggplant ILs with introgression from S. incanum was evaluated for fruit shape in two environments. Specifically, we performed a detailed phenotyping of the fruits of the parents, hybrid, and ILs using 32 morphological descriptors of the phenomics tool Tomato Analyzer. Large differences in fruit morphology were found between ILs parents, and the hybrid exhibited negative values of heterosis for many fruit shape traits, being phenotypically closer to S. incanum parent. For most fruit shape descriptors, we observed significant differences between ILs and recipient parent, even in the presence of small wild donor fragments. Although the contribution of the environment and G × E interaction were significant for almost all descriptors, we found that their effects on fruit shape were relatively low, and the observed variations in fruit shape was mainly genetically regulated. Hierarchical clustering revealed nine clusters of highly correlated traits and six ILs groups. A total of 41 QTLs were mapped. Of these, sixteen associated to Basic Measurement and Fruit Shape Index descriptors were syntenic to other previously reported in several intraspecific and interspecific eggplant populations, while twenty-five QTLs related to Blockiness, Homogeneity.... / This work was undertaken as part of the initiative “Adapting Agriculture to Climate Change: Collecting, Protecting, and Preparing Crop Wild Relatives”, which is supported by the Government of Norway. The project is managed by the Global Crop Diversity Trust with the Millennium Seed Bank of the Royal Botanic Gardens, Kew and implemented in partnership with national and international gene banks and plant breeding institutes around the world. For further information, see the project website: http://www.cwrdiversity.org/. Funding was also received from Spanish Ministerio de Economía, Industria y Competitividad and Fondo Europeo de Desarrollo Regional (grant AGL2015-64755-R from MINECO/FEDER); from Ministerio de Ciencia, Innovación y Universidades, Agencia Estatal de Investigación and Fondo Europeo de Desarrollo Regional (grant RTI-2018-094592-B-100 from MCIU/AEI/FEDER, UE); from European Union’s Horizon 2020 Research and Innovation Programme under grant agreement No. 677379 (G2P-SOL project: Linking genetic resources, genomes and phenotypes of Solanaceous crops); and from Vicerrectorado de Investigación, Innovación y Transferencia de la Universitat Politècnica de València (Ayuda a Primeros Proyectos de Investigación; PAID-06-18). Giulio Mangino is grateful to Generalitat Valenciana for a predoctoral grant within the Santiago Grisolía programme (GRISOLIAP/2016/012). / Mangino, G. (2022). Development and use of introgression populations for the detection of QTL related to important agronomic traits in eggplant [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/188916 / Compendio
132

Soybean QTL Mapping and Candidate Gene Identification for Pythium irregulare and Phytophthora sojae Partial Resistance; and Root-Knot Nematode Induced Suppression of Gene Silencing

Nauth, Brittany J. 29 October 2014 (has links)
No description available.
133

Évaluation neurobiologique des souris spontanément hypertendues : Du vieillissement à la génomique comparative

Thifault, Stéphane 12 1900 (has links)
Le but de cette thèse est premièrement d’évaluer l’effet du vieillissement sur les fonctions psychomotrices des souches de souris sélectionnées génétiquement en fonction de leur tension artérielle (TA); deuxièmement, de localiser les déterminants génétiques des phénotypes psychophysiologiques à partir de souches recombinantes congéniques (RCS). Ces travaux ont mené à la publication de 4 articles. Le premier article décrit l’évaluation des fonctions psychomotrices des souches avec une tension artérielle élevée (HBP), basse (LBP) et normale (NBP). La performance aux épreuves d’exploration, d’habiletés motrices et d’apprentissage spatial, a été mesurée sur deux cohortes âgées respectivement de 12 mois et de trois mois. Indépendamment de l’âge, les HBPs sont hyperactives dans l’open-field (OF), mais pas dans le test d’exploration de trous. Inversement, les LBP explorent moins d’espaces que les NBP et, à trois mois seulement, sont hypoactives dans l’OF. Par ailleurs, les HBPs et les LBP présentent des déficits précoces de coordination motrice et des fonctions visuo-motrices. Le second article concerne l’évaluation longitudinale de la coordination motrice, de l’anxiété et de l’apprentissage spatial des souches HBP, LBP et NBP, à l’âge de deux mois et de 12 mois. Le vieillissement accentue l’hyperactivité des HBPs dans l’OF. Par contre, l’hypoactivité des souris LBP est détectable seulement à l’âge de deux mois. Indépendamment de l’âge, les souris HBP et LBP montrent une perception réduite du danger dans l’épreuve d’anxiété et des dysfonctions visuo-motrices au labyrinthe aquatique. Enfin, des déficits précoces de coordination motrice se manifestent seulement chez les HBPs. Il reste à déterminer si les déficits observés sont liés à des déterminants génétiques indépendants ou secondaires aux altérations de la tension artérielle. Le troisième article présente la comparaison entre les souches consanguines A/J et C57Bl/6J (B6) aux épreuves de l’OF, de la planche à trous, du labyrinthe aquatique et du cintre (coordination motrice). Les B6 explore d’avantage l’OF et la planche à trous. Les B6 sont moins rapides sur le cintre, mais supérieurs aux A/J dans le labyrinthe aquatique, avec une plate-forme invisible ou visible. Ces résultats démontrent l’implication de déterminants génétiques. Cette thèse se termine par un quatrième article sur la localisation des déterminants génétiques de la susceptibilité au stress dans les RCS, dérivées de A/J et B6, et présentant un agencement spécifique de 12.5% du génome. La réactivité émotionnelle est évaluée dans l’OF et le plus-maze; la réponse de stress est mesurée par radio télémétrie de la température interne pendant le stress d’immobilisation (SI) sous diète régulière et riche en sel; l’excrétion des électrolytes urinaires est dosée après 24 heures de diète salée. Les loci les plus significatifs sont situés dans les régions suivantes: de l’émotionalité dans l’OF (Emo1) sur le chr. 1 (LOD=4.6) correspondant à la région homologue impliquée dans la cohorte d’hypertension familiale du Saguenay; de la dopa décarboxylase (ddc) sur le chr. 11 pour l’émergence du plus-maze (LOD=4.7); de la protéine liant l’endotoxine (lbp) sur le chr. 2 pour l’hypothermie initiale en réponse au SI (LOD=4); et de HSP90 sur le chr. 12 pour l’excrétion de Ca++ (LOD=4.6). Des banques de données sont ensuite interrogées pour recenser les polymorphismes des régions régulatrices ou codantes des gènes candidats chez les souches ancestrales A/J et B6, dont les séquences sont disponibles pour le génome entier. Des utilitaires web permettent de dévoiler les changements dans la structure secondaire de l’ARNm, l’interférence avec des microARN ou avec d’autres motifs de liaison. Plusieurs SNPs fonctionnels ont été identifiés pour le QTL du chr. 1, particulièrement dans les éléments de régulation; ceux-ci impliquant des gènes reliés avec les réponses inflammatoire/immunitaire ou avec le système cardiovasculaire. La quantification par la PCR confirme une régulation à la baisse d’atp1a2 dans le cœur et le cerveau des souches susceptibles à l’anxiété. Ces résultats confirment l’intrication des altérations de la susceptibilité au stress et de la régulation de la TA. / Our studies in this thesis, which led to 4 publications, are divided in two parts. The first part describes the neuropsychological effects of aging in strains of mice genetically selected for high (HBP), low (LBP) or normal blood pressure (NBP). The second part focuses on the genetic determinants of these neuropsychological phenotypes in recombinant congenic strains (RCS) of mice. The first manuscript compares HBP or LBP mice to normotensive controls in tests of exploration, motor coordination, and spatial learning at two age levels: 3 and 12 months. At either age, HBPs were hyperactive in an open field (OF) but not in terms of hole-poking responses. On the contrary, LBPs were hypoactive in the OF and in the hole-board, with the effect on the former measure being limited to the younger cohort. In either cohort, HBP and LBP mice were deficient in subtle aspects of motor coordination, and visuomotor function. These strains may serve as experimental models for the evaluation of beneficial early antihypertensive or antihypotensive treatments on brain function. The second study uses a longitudinal design to compare either HBP or LBP mice to normotensive controls at 2 and 12 months of age for motor coordination, anxiety, and spatial learning. Hyperactivity of HBPs in the OF increased with aging; whereas LBP mice were hypoactive only at 2 months of age. At both age, HBP and LBP mice displayed reduced levels of anxiety in the elevated plus-maze (EPM), abnormal coordination and visuomotor guidance. It remains to determine if these strain-, age-, and test-specific abnormalities are genetically related or secondary to uncontrolled hypertension or hypotension. The following article compares the C57BL/6J (B6) to the A/J inbred mouse strain in exploration of the OF and the hole-board, in the coat-hanger coordination test, and in spatial learning of a water maze. B6 mice displayed a higher number of segment crossings in the open-field and of hole-poking responses than A/J mice. By contrast to their hypo activity, A/J strain were faster in the coat-hanger motor test, but deficient in the submerged but also in the visible platform version of the water maze. These results indicate the considerable potential of genetic models derived from B6 and A/J mice for discerning the determinants of several behavioural phenotypes. In the last manuscript, the genomic loci bearing stress-related phenotypes were dissected by genome wide analysis of linkage in the recombinant congenic strains (RCS), resulting from a cross of B6 and A/J progenitors, each strain bearing 12.5% of specific parts of one progenitor on the background of the other. Adult male mice from 14 A/J and 22 B6 background lines were evaluated for emotional reactivity in the OF and the EPM. Core temperature was monitored by radio-telemetry during immobilization (IM), under standard and salt-enriched diets. In addition, urinary electrolytes were measured. The highest LOD scores strengthen the evidence for a previously reported locus for emotionality in the open-field on Chr 1 (LOD=4.6), in the Ddc region encoding dopa decarboxylase, on Chr 11 in the EPM (LOD=4.7), near Lbp (lipopolysaccharide binding protein), on Chr 2 for initial hypothermia during IM (LOD=4), as well as in the region of Hspca, encoding heat shock protein 1 alpha (48.0 cM) on Chr 12 for Ca++ excretion after a 24 hr-salt load (LOD=4.6). RCS stress QTL overlapped with several candidate loci for cardiovascular disease. In silico evidence of functional polymorphisms by comparative sequence analysis of progenitor strains assisted to ascertain this convergence, then further tested using quantitative PCR for releant genes mRNA. The anxious BcA70 strain showed down regulation of the Atp1a2 gene expression in the heart (P < 0.001) and brain (P < 0.05) compared to its parental B6 strain, compatible with the enhanced emotionality described in knock out animals for this gene, also involved in the salt-sensitive component of hypertension. Functional polymorphisms in regulatory elements of candidate genes of the cardiovascular / inflammatory / immune systems support the hypothesis of genetically-altered environmental susceptibility in cardiovascular disease development.
134

Investigation des variants génétiques dans la dysfonction endothéliale et le risque de maladies cardiovasculaires.

Codina-Fauteux, Valérie-Anne 08 1900 (has links)
No description available.
135

Évaluation neurobiologique des souris spontanément hypertendues : Du vieillissement à la génomique comparative

Thifault, Stéphane 12 1900 (has links)
Le but de cette thèse est premièrement d’évaluer l’effet du vieillissement sur les fonctions psychomotrices des souches de souris sélectionnées génétiquement en fonction de leur tension artérielle (TA); deuxièmement, de localiser les déterminants génétiques des phénotypes psychophysiologiques à partir de souches recombinantes congéniques (RCS). Ces travaux ont mené à la publication de 4 articles. Le premier article décrit l’évaluation des fonctions psychomotrices des souches avec une tension artérielle élevée (HBP), basse (LBP) et normale (NBP). La performance aux épreuves d’exploration, d’habiletés motrices et d’apprentissage spatial, a été mesurée sur deux cohortes âgées respectivement de 12 mois et de trois mois. Indépendamment de l’âge, les HBPs sont hyperactives dans l’open-field (OF), mais pas dans le test d’exploration de trous. Inversement, les LBP explorent moins d’espaces que les NBP et, à trois mois seulement, sont hypoactives dans l’OF. Par ailleurs, les HBPs et les LBP présentent des déficits précoces de coordination motrice et des fonctions visuo-motrices. Le second article concerne l’évaluation longitudinale de la coordination motrice, de l’anxiété et de l’apprentissage spatial des souches HBP, LBP et NBP, à l’âge de deux mois et de 12 mois. Le vieillissement accentue l’hyperactivité des HBPs dans l’OF. Par contre, l’hypoactivité des souris LBP est détectable seulement à l’âge de deux mois. Indépendamment de l’âge, les souris HBP et LBP montrent une perception réduite du danger dans l’épreuve d’anxiété et des dysfonctions visuo-motrices au labyrinthe aquatique. Enfin, des déficits précoces de coordination motrice se manifestent seulement chez les HBPs. Il reste à déterminer si les déficits observés sont liés à des déterminants génétiques indépendants ou secondaires aux altérations de la tension artérielle. Le troisième article présente la comparaison entre les souches consanguines A/J et C57Bl/6J (B6) aux épreuves de l’OF, de la planche à trous, du labyrinthe aquatique et du cintre (coordination motrice). Les B6 explore d’avantage l’OF et la planche à trous. Les B6 sont moins rapides sur le cintre, mais supérieurs aux A/J dans le labyrinthe aquatique, avec une plate-forme invisible ou visible. Ces résultats démontrent l’implication de déterminants génétiques. Cette thèse se termine par un quatrième article sur la localisation des déterminants génétiques de la susceptibilité au stress dans les RCS, dérivées de A/J et B6, et présentant un agencement spécifique de 12.5% du génome. La réactivité émotionnelle est évaluée dans l’OF et le plus-maze; la réponse de stress est mesurée par radio télémétrie de la température interne pendant le stress d’immobilisation (SI) sous diète régulière et riche en sel; l’excrétion des électrolytes urinaires est dosée après 24 heures de diète salée. Les loci les plus significatifs sont situés dans les régions suivantes: de l’émotionalité dans l’OF (Emo1) sur le chr. 1 (LOD=4.6) correspondant à la région homologue impliquée dans la cohorte d’hypertension familiale du Saguenay; de la dopa décarboxylase (ddc) sur le chr. 11 pour l’émergence du plus-maze (LOD=4.7); de la protéine liant l’endotoxine (lbp) sur le chr. 2 pour l’hypothermie initiale en réponse au SI (LOD=4); et de HSP90 sur le chr. 12 pour l’excrétion de Ca++ (LOD=4.6). Des banques de données sont ensuite interrogées pour recenser les polymorphismes des régions régulatrices ou codantes des gènes candidats chez les souches ancestrales A/J et B6, dont les séquences sont disponibles pour le génome entier. Des utilitaires web permettent de dévoiler les changements dans la structure secondaire de l’ARNm, l’interférence avec des microARN ou avec d’autres motifs de liaison. Plusieurs SNPs fonctionnels ont été identifiés pour le QTL du chr. 1, particulièrement dans les éléments de régulation; ceux-ci impliquant des gènes reliés avec les réponses inflammatoire/immunitaire ou avec le système cardiovasculaire. La quantification par la PCR confirme une régulation à la baisse d’atp1a2 dans le cœur et le cerveau des souches susceptibles à l’anxiété. Ces résultats confirment l’intrication des altérations de la susceptibilité au stress et de la régulation de la TA. / Our studies in this thesis, which led to 4 publications, are divided in two parts. The first part describes the neuropsychological effects of aging in strains of mice genetically selected for high (HBP), low (LBP) or normal blood pressure (NBP). The second part focuses on the genetic determinants of these neuropsychological phenotypes in recombinant congenic strains (RCS) of mice. The first manuscript compares HBP or LBP mice to normotensive controls in tests of exploration, motor coordination, and spatial learning at two age levels: 3 and 12 months. At either age, HBPs were hyperactive in an open field (OF) but not in terms of hole-poking responses. On the contrary, LBPs were hypoactive in the OF and in the hole-board, with the effect on the former measure being limited to the younger cohort. In either cohort, HBP and LBP mice were deficient in subtle aspects of motor coordination, and visuomotor function. These strains may serve as experimental models for the evaluation of beneficial early antihypertensive or antihypotensive treatments on brain function. The second study uses a longitudinal design to compare either HBP or LBP mice to normotensive controls at 2 and 12 months of age for motor coordination, anxiety, and spatial learning. Hyperactivity of HBPs in the OF increased with aging; whereas LBP mice were hypoactive only at 2 months of age. At both age, HBP and LBP mice displayed reduced levels of anxiety in the elevated plus-maze (EPM), abnormal coordination and visuomotor guidance. It remains to determine if these strain-, age-, and test-specific abnormalities are genetically related or secondary to uncontrolled hypertension or hypotension. The following article compares the C57BL/6J (B6) to the A/J inbred mouse strain in exploration of the OF and the hole-board, in the coat-hanger coordination test, and in spatial learning of a water maze. B6 mice displayed a higher number of segment crossings in the open-field and of hole-poking responses than A/J mice. By contrast to their hypo activity, A/J strain were faster in the coat-hanger motor test, but deficient in the submerged but also in the visible platform version of the water maze. These results indicate the considerable potential of genetic models derived from B6 and A/J mice for discerning the determinants of several behavioural phenotypes. In the last manuscript, the genomic loci bearing stress-related phenotypes were dissected by genome wide analysis of linkage in the recombinant congenic strains (RCS), resulting from a cross of B6 and A/J progenitors, each strain bearing 12.5% of specific parts of one progenitor on the background of the other. Adult male mice from 14 A/J and 22 B6 background lines were evaluated for emotional reactivity in the OF and the EPM. Core temperature was monitored by radio-telemetry during immobilization (IM), under standard and salt-enriched diets. In addition, urinary electrolytes were measured. The highest LOD scores strengthen the evidence for a previously reported locus for emotionality in the open-field on Chr 1 (LOD=4.6), in the Ddc region encoding dopa decarboxylase, on Chr 11 in the EPM (LOD=4.7), near Lbp (lipopolysaccharide binding protein), on Chr 2 for initial hypothermia during IM (LOD=4), as well as in the region of Hspca, encoding heat shock protein 1 alpha (48.0 cM) on Chr 12 for Ca++ excretion after a 24 hr-salt load (LOD=4.6). RCS stress QTL overlapped with several candidate loci for cardiovascular disease. In silico evidence of functional polymorphisms by comparative sequence analysis of progenitor strains assisted to ascertain this convergence, then further tested using quantitative PCR for releant genes mRNA. The anxious BcA70 strain showed down regulation of the Atp1a2 gene expression in the heart (P < 0.001) and brain (P < 0.05) compared to its parental B6 strain, compatible with the enhanced emotionality described in knock out animals for this gene, also involved in the salt-sensitive component of hypertension. Functional polymorphisms in regulatory elements of candidate genes of the cardiovascular / inflammatory / immune systems support the hypothesis of genetically-altered environmental susceptibility in cardiovascular disease development.
136

Genetic analysis of resistance to Fusarium head blight in wheat (Triticum spp.) using phenotypic characters and molecular markers

Malihipour, Ali 26 October 2010 (has links)
Fusarium head blight (FHB), caused mainly by Fusarium graminearum (teleomorph: Gibberella zeae), is one of the most damaging diseases of wheat. A ‘Brio’/‘TC 67’ spring wheat population was used to map quantitative trait loci (QTLs) for resistance to FHB, and to study the association of morphological and developmental characteristics with FHB resistance. Interval mapping (IM) detected a major QTL on chromosome 5AL for resistance to disease severity (type II resistance) and Fusarium-damaged kernels (FDK) under greenhouse and field conditions, respectively. Inconsistent QTL(s) was also detected on chromosome 5BS for disease severity and index using field data. The associations of plant height and number of days to anthesis were negative with disease incidence, severity, index, and deoxynivalenol (DON) accumulation data under field conditions. However, number of days to anthesis was positively correlated with disease severity (greenhouse) and FDK (field). Awnedness had a negative effect on FHB, namely the presence of awns resulted in less disease in the population. Spike threshability also affected FHB so that the hard threshable genotypes represented lower disease. Phylogenetic relationships of putative F. graminearum isolates from different sources were characterized using Tri101 gene sequencing data. Canadian and Iranian isolates clustered in F. graminearum lineage 7 (=F. graminearum sensu stricto) within the F. graminearum clade while the isolates received from CIMMYT, Mexico were placed in F. graminearum lineage 3 (=Fusarium boothii) within the Fg clade or Fusarium cerealis. The PCR assay based on the Tri12 gene revealed the presence of the NIV, 3-ADON, and 15-ADON chemotypes with 15-ADON being the predominant chemotype. While we did not find the NIV chemotype among the Canadian isolates, it was the predominant chemotype among the Iranian isolates. High variation in aggressiveness was observed among and within Fusarium species tested, with the isolates of F. graminearum sensu stricto being the most aggressive and the NIV chemotype being the least aggressive. The interactions between Fusarium isolates and wheat genotypes from different sources were investigated by inoculating isolates of F. graminearum sensu stricto and F. boothii on wheat genotypes. Significant differences were observed among the genotypes inoculated by single isolates. Results also showed significant interactions between Fusarium isolates and wheat genotypes. The F. boothii isolates from CIMMYT produced low disease symptom and infection on wheat genotypes regardless of the origin of the genotypes while F. graminearum sensu stricto isolates from Canada and Iran resulted in higher FHB scores.
137

Genetic analysis of resistance to Fusarium head blight in wheat (Triticum spp.) using phenotypic characters and molecular markers

Malihipour, Ali 26 October 2010 (has links)
Fusarium head blight (FHB), caused mainly by Fusarium graminearum (teleomorph: Gibberella zeae), is one of the most damaging diseases of wheat. A ‘Brio’/‘TC 67’ spring wheat population was used to map quantitative trait loci (QTLs) for resistance to FHB, and to study the association of morphological and developmental characteristics with FHB resistance. Interval mapping (IM) detected a major QTL on chromosome 5AL for resistance to disease severity (type II resistance) and Fusarium-damaged kernels (FDK) under greenhouse and field conditions, respectively. Inconsistent QTL(s) was also detected on chromosome 5BS for disease severity and index using field data. The associations of plant height and number of days to anthesis were negative with disease incidence, severity, index, and deoxynivalenol (DON) accumulation data under field conditions. However, number of days to anthesis was positively correlated with disease severity (greenhouse) and FDK (field). Awnedness had a negative effect on FHB, namely the presence of awns resulted in less disease in the population. Spike threshability also affected FHB so that the hard threshable genotypes represented lower disease. Phylogenetic relationships of putative F. graminearum isolates from different sources were characterized using Tri101 gene sequencing data. Canadian and Iranian isolates clustered in F. graminearum lineage 7 (=F. graminearum sensu stricto) within the F. graminearum clade while the isolates received from CIMMYT, Mexico were placed in F. graminearum lineage 3 (=Fusarium boothii) within the Fg clade or Fusarium cerealis. The PCR assay based on the Tri12 gene revealed the presence of the NIV, 3-ADON, and 15-ADON chemotypes with 15-ADON being the predominant chemotype. While we did not find the NIV chemotype among the Canadian isolates, it was the predominant chemotype among the Iranian isolates. High variation in aggressiveness was observed among and within Fusarium species tested, with the isolates of F. graminearum sensu stricto being the most aggressive and the NIV chemotype being the least aggressive. The interactions between Fusarium isolates and wheat genotypes from different sources were investigated by inoculating isolates of F. graminearum sensu stricto and F. boothii on wheat genotypes. Significant differences were observed among the genotypes inoculated by single isolates. Results also showed significant interactions between Fusarium isolates and wheat genotypes. The F. boothii isolates from CIMMYT produced low disease symptom and infection on wheat genotypes regardless of the origin of the genotypes while F. graminearum sensu stricto isolates from Canada and Iran resulted in higher FHB scores.
138

Characterization of Corn Fibres for Manufacturing Automotive Plastic Parts

Riaz, Muhammad 04 January 2013 (has links)
The study examined the properties of stalk and cob fibres from recombinant inbred corn lines and their parents, grown at two locations, in a polylactic acid (PLA) matrix. The objectives were to: determine fibre compositions; evaluate the effects of fibres on the functional properties of biocomposites and identify quantitative trait loci (QTLs) and gene markers for fibre performance in biocomposites. Significant Genotype*Location effects were observed. Composites had lower strength (impact, tensile, and flexural) but higher tensile/flexural modulus values than pure PLA. The latter were positively affected by cellulose and hemicellulose but negatively affected by free phenolic levels and 93 fibre QTLs and 62 composite markers were detected. This study identified fibre traits and markers for genes that may be important for the use of corn fibres in biocomposites. / Ontario BioCar Initiative Project funded by Ontario Ministry of Research and Innovation, Agriculture and Agri-Food Canada, The Natural Sciences and Engineering Research Council, The Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) and Ontario Public Sector

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