A ocorrência de doenças em uvas de mesa gera perdas desde o cultivo até a comercialização, o que afeta diretamente o potencial de exportação do Brasil. A prevenção na realização de injúrias nos frutos é essencial para garantir a eficácia dos tratamentos aplicados tanto em pré- quanto em pós-colheita. Visando o emprego de produtos alternativos que auxiliem no manejo sustentável da cultura, o fosfito de potássio encontra-se como ferramenta útil. O efeito do fosfito no controle de doenças causadas por oomicetos já foi relatado, porém, como este ingrediente ativo atua sobre microrganismos do reino Fungi ainda é desconhecido. Neste contexto, este trabalho teve como objetivo avaliar o fosfito de potássio no controle das doenças podridão mole, mofo cinzento e podridão da uva madura, causadas por Rhizopus stolonifer, Botrytis cinerea e Colletotrichum gloeosporioides, respectivamente, em bagas de uva ´Itália´ e seus efeitos na qualidade físico-química dos frutos. Também objetivou-se estudar os mecanismos de ação envolvidos na inibição do desenvolvimento do micélio de R. stolonifer na presença do produto e na indução de respostas de defesa em bagas de uva. Foram realizados ensaios in vitro para avaliação do efeito do fosfito sobre o crescimento micelial, esporulação e germinação dos esporos para R. stolonifer, B. cinerea e C. gloeosporioides. Experimentos utilizando-se de bagas foram conduzidos, visando avaliar o efeito no uso do fosfito como fungicida produtor ou curativo para os três patógenos. Cachos foram utilizados para se determinar os efeitos da aspersão do fosfito sobre a qualidade físico-química dos frutos. Para avaliação dos mecanismos de ação do fosfito sobre o micélio de R. stolonifer, foram determinados os efeitos sobre a permeabilidade da membrana plasmática, a síntese de parede celular e a síntese de proteínas. A atividade de guaiacol peroxidase e de compostos fenólicos totais foi determinada em bagas de uva tratadas ou não com fosfito. Houve inibição do crescimento micelial, da esporulação e da germinação dos esporos dos patógenos desenvolvidos em diferentes concentrações de fosfito de potássio. O tratamento protetor e curativo das bagas evidenciou reduções significativas na área abaixo da curva de progresso das doenças estudadas. Não houve efeito do produto sobre a qualidade físico-química dos cachos de uva. Quanto aos mecanismos de ação, foram observados efeitos do fosfito sobre a permeabilidade de membrana, devido à elevada perda de eletrólitos do micélio. O fosfito proporcionou elevação na síntese de proteínas totais no micélio do patógeno e redução na atividade de ?-1,3- glucanase e quitinase, que são enzimas relacionadas à síntese de parede. A atividade de guaiacol peroxidase e a concentração de compostos fenólicos totais não aumentou com a aplicação do fosfito nas bagas. Desta forma, pode-se concluir que o fosfito de potássio controlou a podridão mole, o mofo cinzento e a podridão da uva madura e não teve efeito sobre a qualidade físico-química dos frutos. Ainda, o fosfito atuou sobre a permeabilidade de membrana, síntese de proteínas e de parede celular do micélio de R. stolonifer e não proporcionou indução da atividade de guaiacol peroxidase e compostos fenólicos totais em bagas de uva. / The occurrence of table grape diseases causes losses from the field to the commercialization, which affects the Brazil potential to export. The prevention of injuries in fruits is essential to ensure the pre- and postharvest treatment efficiency. In order to use alternative products to support the crop sustainable management, phosphite may be a useful tool. The phosphite effect on control of diseases caused by oomycetes has been reported, however, how the active ingredient acts on microorganisms from the Fungi kingdom is unknown. Thus, the objective was to evaluate potassium phosphite on the control of soft rot, grey mold and ripe rot, caused by Rhizopus stolonifer, Botrytis cinerea e Colletotrichum gloeosporioides, respectively, in ´Itália´ grape berries and its effect on physico-chemical properties of the fruits. Moreover, the objective was to study the mode of action involved on the inhibition of R. stolonifer grown in the presence of phosphite and on the induction of defense responses in grape berries. In vitro assays were carried out to evaluate the effect of phosphite on mycelial growth, sporulation and spore germination in R. stolonifer, B. cinerea e C. gloeosporioides. Single berries were used in order to evaluate the effect of phosphite as a protective or curative fungicide against the three pathogens. Grape clusters were used to determine the effects of phosphite spraying on physico-chemical properties. To evaluate the mode of action of phosphite on R. stolonifer mycelium the plasma membrane permeability, the protein synthesis and the cell wall synthesis were monitored. The guaiacol peroxidase activity and phenolic compound concentration were evaluated in grape berries treated or not with phosphite. There were inhibition on mycelial growth, sporulation and spore germination on the three pathogens in different potassium phosphite concentrations. The protective and curative treatment in grape berries showed significant reductions on the area under disease progress curve of the studied diseases. There was no effect on physico-chemical properties of the grapes. Regarding the mode of action, the phosphite affected membrane permeability what was seen as high electrolyte leakage from the mycelium. Phosphite caused high protein synthesis in the mycelium and reduction on ?-1,3-glucanase and chitinase activities, which are enzymes related to cell wall synthesis. The guaiacol peroxidase activity and phenolic compound concentration did not increase due the phosphite application. Thus, it may be concluded that potassium phosphite controlled soft rot, grey mold and ripe rot in grape berries and did not affect the physico-chemical properties of the fruits. Besides that, phosphite still acted on membrane permeability, protein synthesis and cell wall synthesis on the R. stolonifer mycelium and did not changes in guaiacol peroxidase activity and phenolic compound concentration in the grape berries.

O conhecimento da interferência do porta-enxerto no desenvolvimento da copa é muito importante, pois tais interações para cada combinação porta-enxerto e cultivar copa adotada pode variar. Dessa forma, o objetivo deste trabalho foi avaliar a interferência dos porta-enxertos \'IAC 766\', \'IAC 572\', \'IAC 313\', \'IAC 571-6\' e \'Ripária do Traviú\', no desenvolvimento e fertilidade das gemas da cultivar copa \'Niagara Rosada\'. O estudo foi realizado em videira \'Niagara Rosada\' conduzida sob o sistema de espaldeira, na região de Jundiaí - SP. As avaliações foram realizadas em três ciclos de produção, destes, dois foram realizados no ciclo tradicional, em que a poda de produção é realizada no inverno e a colheita no fim da primavera e início de verão, e um foi realizado na denominada safrinha, em que a poda de produção ocorre no verão e a colheita no fim do outono e início do inverno. Para os ciclos de produção tradicionais avaliou-se a fertilidade da primeira até a quarta ou quinta gema, o número de brotação, o número de cacho e o comprimento final dos ramos em 2014 e 2015. No ciclo de produção safrinha avaliou-se a fertilidade da quinta até a oitava gema e os demais dados biométricos durante o cultivo. Nesse ciclo de produção avaliou-se a produção e qualidade de frutos da videira. O delineamento experimental adotado foi em blocos casualizados em esquema de parcela subdividida para fertilidade de gemas, e em blocos casualizados para as demais variáveis. Os dados coletados foram submetidos à análise de variância, e quando significativo, os dados foram submetidos ao teste de comparação de médias Tukey a 0,05 de probabilidade. Não foi observado efeito dos diferentes porta-enxertos na fertilidade de gemas, no desenvolvimento da planta, na produção e qualidade dos frutos de videira \'Niagara Rosada\'. / The knowledge about rootstock interference in scion development is important, because these interactions can vary with the combination of rootstock and scion. Thus, the aim of this study was to analyze the interaction of the rootstocks \'IAC 766\', \'IAC 572\', \'IAC 313\', \'IAC 571-6\' e \'Ripária do Traviú\' to the development and bud fruitfulness of \'Niagara Rosada\' scion. This study was conducted in \'Niagara Rosada\' training by espalier system in Jundiaí - SP region. The experiment was performed in three crop seasons, two called traditional season, when the pruning is done in winter and the harvest in the end of spring and beginning of summer, and one non-traditional crop season, when pruning is performed in summer and the harvest in the end of fall or beginning of winter. In traditional crop season was evaluated the fruitfulness from first to fourth or fifth bud, the budburst, the number of cluster and the shoot length in 2014 and 2015. In non-traditional crop season was evaluated fruitfulness from fifth from eighth bud, likewise the biometric data. Furthermore, in this crop season was evaluated the yield and fruit quality of grapevine \'Niagara Rosada\'. The statistical design t was randomized blocks in split plot for fruitulness, and randomized blocks for the other trials. The data was submitted to analysis of variance, and the means were compared to Tukey test at 0,05 of probability. There was no effect of rootstock on fruitfulness, development of plant, yield and fruit quality of grape \'Niagara Rosada\'.

Orientadores: Helena Teixeira Godoy, Roger Wagner / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-23T09:21:02Z (GMT). No. of bitstreams: 1 Rodrigues_Daniele_D.pdf: 2460072 bytes, checksum: c95a5ef47b314914e0a09d0a616b0186 (MD5) Previous issue date: 2013 / Resumo: O aroma dos vinhos é formado por compostos provenientes das uvas e por compostos formados durante a vinificação, caracterizando a identidade, a tipicidade e a qualidade do vinho. A fermentação alcoólica é o processo de maior importância para a formação desses compostos. Porém, a falta de nutrientes nos mostos, como o nitrogênio, pode resultar em uma fermentação lenta, com a formação insuficiente da biomassa e, consequentemente, a baixa síntese de compostos de aroma. A qualidade de certos vinhos também pode ser prejudicada pela presença de compostos indesejáveis, os offflavours. Dentre esses compostos estão as metoxipirazinas que, em altas concentrações, são responsáveis pelo aroma herbáceo ou de pimentão verde em uvas Cabernet sauvignon, sendo incorporadas no vinho durante o processo de vinificação. Alguns parâmetros têm sido relacionados com as altas concentrações desses compostos, sendo o mais importante a maturação incompleta das uvas na época da colheita, que pode ser influenciada por fatores naturais como a umidade do ar, as precipitações pluviométricas e a temperatura. Diante do exposto, este trabalho foi desenvolvido com o intuito de suprir a falta de nitrogênio no mosto durante a vinificação e de diminuir a concentração de metoxipirazinas nas uvas e nos vinhos. Para isso, diferentes práticas de manejo foram aplicadas nos vinhedos. A pulverização de amônia no solo dos vinhedos das cultivares Merlot, Cabernet franc e Cabernet sauvignon, foi testada para a obtenção de nitrogênio necessário para a fermentação alcoólica e a produção dos compostos de aromas. Para isso, os vinhedos foram divididos em parcelas e receberam diferentes concentrações de amônia (10, 60, 90, 120 e 180 kgN.Hectare-1). Na época da vindima, as uvas foram colhidas e analisadas quanto aos teores de nitrogênio assimilável e de aminoácidos, sendo em seguida vinificadas, e os vinhos analisados quanto aos teores de álcoois superiores e de ésteres. A dupla poda e a cobertura do vinhedo foram realizadas com a cultivar Cabernet sauvignon e testadas para a diminuição de metoxipirazinas na uva e no vinho. Amostras de uvas foram colhidas durante todo o período de maturação, com o intuito de acompanhar as concentrações de metoxipirazinas. Na época da vindima, as uvas foram colhidas e analisadas quanto aos seus teores de metoxipirazinas, sólidos solúveis totais e pH, sendo em seguida vinificadas, e os vinhos analisados quanto aos seus teores de metoxipirazinas. Os resultados mostraram que todas as técnicas de manejo aplicadas nos vinhedos foram eficientes e conseguiram atingir seus objetivos. Com relação à pulverização de amônia, os tratamentos que receberam maiores concentrações desse composto no solo apresentaram concentrações mais elevadas de nitrogênio assimilável (167,163 e 184 mg.L-1) e de aminoácidos (752, 921 e 998 mg.L-1) nos mostos, se comparados com os tratamentos controles (128,103 e 115 mg.L-1 para nitrogênio assimilável e 534, 542 e 601 mg.L-1 para aminoácidos), indicando que as plantas foram capazes de absorver esse composto do solo e utilizá-lo na produção de aminoácidos. A presença de elevadas concentrações de nitrogênio assimilável e de aminoácidos nos mostos influenciou e acelerou a fermentação alcoólica das varietais Merlot e Cabernet sauvignon, cujos tratamentos que apresentaram as maiores concentrações de nitrogênio assimilável tiveram seu tempo de fermentação reduzido de 9 para 7 dias. Adicionalmente, os vinhos elaborados com as uvas oriundas desses mesmos tratamentos apresentaram as maiores concentrações de álcoois superiores (190, 443 e 356 mg.L-1) e de ésteres (6505, 6440 e 6298 ]g.L-1), indicando que a síntese desses compostos foi beneficiada pela presença das altas concentrações de nitrogênio assimilável e de aminoácidos. Sendo assim, conclui-se que a pulverização de amônia no solo foi satisfatória, pois forneceu nitrogênio suficiente para o desenvolvimento da fermentação alcoólica e para a produção de compostos aromáticos. Com relação às metoxipirazinas, os resultados mostraram que elas sofreram degradação ao longo do período de maturação, com valores para a concentração de IBMP (2-metoxi-3-isobutilmetoxipirazina) iniciando em 46 ng.L-1 e finalizando abaixo 2,5 ng.L-1. A cobertura do vinhedo foi a técnica mais eficiente na redução de metoxipirazinas em safras colhidas no verão, apresentando uvas com concentração final máxima para a IBMP de 5,27 ng.L-1, sugerindo que a alta temperatura abaixo da cobertura favoreceu a degradação desses compostos. Porém, a dupla poda inverteu a época da colheita do verão para o inverno,época mais fria e de menor intensidade pluviométrica, contribuindo para o aumento do tempo para as bagas atingirem a maturação ideal e, indiretamente, favorecendo a degradação das metoxipirazinas durante este tempo, chegando a valores finais de concentração inferiores a 2,5 ng.L-1, tornando assim a dupla poda o tratamento mais eficaz para a redução das metoxipirazinas nas uvas e, consequentemente, no vinho / Abstract: The aroma of the wine is made by compounds from grapes and compounds formed during the vinification, featuring the identity, typicality and quality of wine. Alcoholic fermentation is the process of greater importance for the formation of these compounds. However, the lack of nutrients in musts, such as nitrogen, can result in a slow fermentation, with the formation of biomass insufficient and the lower synthesis of aromatic compounds. The quality of certain wines may also be impaired by the presence of undesirable compounds, the off-flavours. Among these compounds are the methoxypyrazines that, in high concentrations, are responsible for the flavor herbaceous or green peppers in grapes Cabernet Sauvignon, being incorporated into the wine during the winemaking process. Some parameters have been related to high concentrations of these compounds, the most important is the unripe grapes at harvest time, which can be influenced by natural factors such as humidity, rainfalls and temperature. Given the above, this work has been developed in order to address the lack of nitrogen in musts during vinification and decrease the concentration of methoxypyrazines in grapes and wines. For this, different management practices were applied in the vineyards. Spraying ammonia into the soil vineyards of Merlot, Cabernet franc and Cabernet Sauvignon was tested to obtain nitrogen necessary for the fermentation and production of flavor compounds. For this, the vineyards were divided into plots and received different concentrations of ammonia (10, 60, 90, 120 and 180 kgN.Hectare-1). At the time of harvest, the grapes were harvested and analyzed for the levels of assimilable nitrogen and amino acids, after they were vinified and the wines were analyzed for the levels of higher alcohols and esters. The double pruning and coverage vineyard were conducted with the cultivar Cabernet Sauvignon and tested to decrease methoxypyrazines in grapes and wine. Samples were harvested during all the maturing period in order to monitor the concentrations of methoxypyrazines. At the time of harvest, the grapes were harvested and analyzed for their content of methoxypyrazines, soluble solids and pH, after they were vinified and the wines were analyzed for their content of methoxypyrazines. The results showed that all the management techniques applied in vineyards were efficient and to achieve their objectives. Regarding the addition of ammonia, the treatments that received higher concentrations of this compound in the soil showed higher concentrations of assimilable nitrogen (167, 163 and 184 mg.L-1) and amino acids (752, 921 and 998 mg L-1) in must, when compared to control treatments (128, 103 and 115 mg.L-1 for assimilable nitrogen and 534, 542 and 601 mg.L-1 for amino acids), indicating that the plants were able to absorb the compound of the soil and use it for the amino acid production. The presence of high concentrations of assimilable nitrogen and amino acids in musts influenced and accelerated the alcoholic fermentation of Merlot and Cabernet Sauvignon, the treatments that presented the highest concentrations of assimilable nitrogen had their fermentation time reduced from 9 to 7 days. Additionally, the wines produced with grapes coming from these same treatments had higher concentrations of higher alcohols (190, 443 and 356 mg L-1) and ester (6505, 6440 and 6298 ]g.L-1), indicating that the synthesis of these compounds was benefited by the presence of high concentrations of assimilable nitrogen and amino acids. Therefore, it is concluded that the addition of ammonia in the soil was satisfactory, because it supplied sufficient nitrogen to the development of alcoholic fermentation and the production of aromatic compounds. With respect to methoxypyrazines, the results showed that they undergo degradation during the maturation period, with values for the concentration of IBMP (2-methoxy-3-isobutylpyrazine) starting at 46 ng.L-1 and ending below 2,5 ng.L-1. The coverage vineyard technique was more effective in reducing methoxypyrazines in crops harvested in summer, with grapes with a maximum final concentration of IBMP of 5,27 ng.L-1, suggesting that high temperature below de coverage favored the degradation of these compounds. However, double pruning reversed the harvest season from summer to winter, coldest and least rainfall intensity, contributing to the increase in time for the berries reach optimum ripeness and, indirectly favoring the degradation of methoxypyrazines during this time, reaching a final concentration values below 2,5 ng.L-1, thus making the double pruning the most effective treatment for reducing methoxypyrazines in grapes and wines / Doutorado / Ciência de Alimentos / Doutora em Ciência de Alimentos

Les proanthocyanidines (PA) du raisin jouent un rôle majeur dans les propriétés organoleptiques du vin notamment dans l'astringence et la stabilité de la couleur. Elles sont accumulées principalement dans la pellicule et les pépins pendant les premiers stades du développement de la baie. La biosynthèse des PA commence à être bien décrite, cependant certaines étapes restent à élucider.Une étude transcriptomic avait permis d'indentifier de nouveaux gènes potentiellemnt impliqués dans la biosynthèse des PA (Terrier et al., 2009). Parmi ces gènes figuraient 3 glucosyltransférases et 2 glucose- acyltransférases.Les trois glucosyltransférases VvgGT1, VvgGT2 et VvgGT3 présentent de fortes homologies entres elles et avec d'autres glucosyltransférases capables de catalyser la formation de glucose ester. Les transcrits sont exprimés durant les premiers stades de développement de la baie principalement dans les pépins et la pellicule mais aussi dans la pulpe pour VvgGT2. Les propriétés de ces 3 enzymes (Km, Vm, spécificité de substrat, effet du pH) ont été étudiées in vitro après production de protéines recombinantes. Les 3 VvgGTs sont capables de catalyser la synthèse d'esters de glucose en présence de dérivés d'acide hydroxybenzoique ou d'acide hydroxycinnamique.Deux acyltransférases VvGAT1 et VvGAT2 ont été isolées. Elle présente de fortes similarités avec des acyltransférases glucose-ester dépendantes de type serine carboxypeptidase like. Les transcrits sont exprimés surtout avant la véraison, dans les pépins et la pellicule pour VvGAT1 et dans la pulpe et les pépins pour la VvGAT2. L'expression hétérologue dans différents hôtes n'a pas permis de détecter d'activité enzymatique. Les analyses en microscopie confocale suggèrent que VvGAT1 fusionnée à une GFP est localisée dans des vésicules cytoplasmiques.L'implication successive des VvgGTs et des VvGATs dans la galloylation des PA et dans la synthèse d'esters d'acides hydroxcinnamiques est discutée. / Grape proanthocyanidins (PA) play a major role in organoleptic properties of wine, being involved in astringency and color stability. They are accumulated mainly in skin and seeds during early stages of berry development. Numerous structural genes involved in PA biosynthesis have already been identified even in grape, but some steps are still not documented.A previous transcriptomic study led to identify new genes putatively involved in the PA pathway (Terrier et al., 2009). Among them, 3 glucosyltransferases and 2 glucose acyl transferases were identified. The objective of this work is to clarify the function of these genes in the phenylpropanoid pathway.The three glucosyltransferases called VvgGT1, VvgGT2, VvgGT3 displayed high sequence similarities between them and with other plant glucosyltransferases able to catalyze the formation of glucose esters. The transcripts are expressed in the early stages of grape berry development, mainly in skins and seeds and also in the pulp for VvgGT2. The properties of these 3 enzymes (Km, Vm, substrate specificity, pH sensitivity) were studied in vitro after production of recombinant proteins. The three of them are able to catalyse the synthesis of glucose ester with derivates of hydroxybenzoic acids and hydroxycinnamic acids as substrates and with similar kinetic properties.Two glucose-acyltransferases called VvGAT1 and VvGAT2 were isolated. They displayed high sequence similarity with other Serine carboxypeptidase like acyltransferases-glucose dependent. The transcripts are expressed in early stages of grape berry development mainly in skins and seeds for VvGAT1 and in pulp and seeds for VvGAT2. Heterologous expression of the proteins in different hosts were unsuccessful. The confocal microscopy data suggest that VvGAT1 fused to GFP are localized in cytosolic vesicles.The successive involvement of those VvgGT and VvGAT in the galloylation of PAs and in the synthesis of hydroxycinnamic esters is discussed.

Les flavonoïdes sont des substances naturelles connues pour leurs propriétés anti-inflammatoires, anti-cancéreuses ou anti-virales chez l'homme. Chez les végétaux, ils participent notamment à leur protection vis-à-vis d'organismes pathogènes. La voie de biosynthèse des flavonoïdes est l'une des plus étudiées chez les plantes et notamment chez la vigne : Vitis vinifera. Cependant, la ou les enzymes impliquées dans les dernières étapes de biosynthèse conduisant aux anthocyanes et aux proanthocyanidines restent, à ce jour, peu ou pas connues. L’étude que nous proposons a pour but de concevoir des sondes moléculaires d’affinité susceptibles d’interagir avec une ou plusieurs enzymes impliquées dans ces dernières étapes de biosynthèse. Ces sondes, basées sur la technologie émergeante de protéomique chimique : « Activity- and affininity Based Protein Profiling » (ABPP), ont été validées à l’aide d’une enzyme modèle : la leucoanthocyanidine dioxygénase (LDOX). Elles ont ensuite été appliquées à des extraits complexes de protéines issus de Vitis vinifera. / Flavonoids are natural substances known for their anti-inflammatory, anti-cancerous and anti-virals properties in humans. In plants, they are one of the molecules responsible for fighting pathogens. The flavonoid biosynthesis pathway as been greatly studied in plants, especially in that of the grapevine: Vitis vinifera. However, detailed studies of the exact function of the enzymes involved in the last steps of the biosynthesis of anthocyanins and proanthocyanidins remains largely lacking.The study that we propose is to synthesize molecular probes designed to specifically interact with enzymes involved in the last stages of flavonoids biosynthesis. Our probes, based on the emerging chemical proteomic technology, activity- and affinity based protein profiling (ABPP), were validated with a model enzyme: leucoanthocyanidin dioxygenase (LDOX). After which, they were used with complex protein mixtures from Vitis vinifera.

Le raisin (Vitis vinifera L.) est un fruit charnu non climactérique d’importance économique majeure. De nombreux paramètres, comme la taille, le métabolisme des acides organiques et des sucres, l’équilibre hydrique et la synthèse de métabolites secondaires, affectent la « qualité » de la baie. Les signaux affectant la reprogrammation du métabolisme cellulaire et l’expression des gènes codant des protéines clefs du développement et du mûrissement incluent les hormones et l’accumulation des sucres, présents à des taux variables au cours du développement de la baie. La régulation transcriptionnelle est l’élément essentiel qui contrôle ces modifications majeures. A ce jour, dans le contexte de la régulation du développement du raisin, très peu d’acteurs moléculaires ont pu être clairement caractérisés. Les travaux réalisés dans le cadre de cette thèse ont donc eu pour objectif de mieux comprendre cette régulation par l’identification et la caractérisation de facteurs de transcription régulés transcriptionnellement par le saccharose et exprimés au cours du développement de la baie de raisin. Parmi les cinq facteurs de transcription identifiés, trois n’ont pu être étudiés que de manière préliminaire et deux, VvCEB1 et VvABF2, ont fait l’objet d’une caractérisation plus approfondie. VvCEB1 (Vitis vinifera Cell Elongation bHLH) est exprimé préférentiellement dans la baie de raisin au cours de la phase de maturation. Une approche par transgénèse chez la Vigne et la Tomate montre que la surexpression de ce facteur de transcription affecte à la fois le développement des embryons de Vigne et des fruits de Tomate, en modifiant notamment le nombre et la taille des cellules qui les constituent. Une analyse transcriptionnelle réalisée à partir de ce matériel biologique confirme le rôle de VvCEB1 dans la stimulation de l’expansion cellulaire et suggère l’implication de l’auxine. VvABF2 est régulé transcriptionnellement par l’ABA, une hormone clef impliquée dans les processus de maturation des fruits non climactériques. Les transcrits VvABF2 s’accumulent majoritairement pendant l’étape de maturation. Une approche transcriptomique sur génome complet de Vigne et réalisée à partir de suspensions cellulaires embryogènes surexprimant VvABF2, traitées ou non par l’ABA souligne la stimulation de l’expression des gènes codant les enzymes liées à la maturation du raisin. En effet, des gènes des voies de biosynthèse des composés phénoliques et du ramollissement sont affectés. Enfin, l’analyse phénotypique de plants de Tomate surexprimant VvABF2 renforce l’hypothèse liant ce facteur de transcription au ramollissement : à partir du stade "turning" un ramollissement accéléré du fruit est observé.Prise dans son ensemble cette thèse contribue à une meilleure compréhension des mécanismes de signalisation moléculaires impliqués dans le développement d’un fruit charnu non climactérique. / Grapevine (Vitis vinifera L.) is the most economically important fruit crop in the world. The quality of this non climacteric fruit depends on numerous parameters such as size, organic acids and sugar metabolisms, water balance, and secondary metabolism. During fruit development and ripening, hormones and sugars can act as signals affecting cellular metabolism and expression of key regulatory genes. Up to now, little is known about the gene networks involved in these processes and therefore very few of these regulatory genes have been characterized.The aim of this PhD work was to get a better insight in the mechanisms involved in grape berry development through the identification and characterization of sugar-dependent transcription factors (TFs) that were expressed during fruit development. We identified five TFs, and fully characterized two of them: VvCEB1 and VvABF2.VvCEB1 (Vitis vinifera Cell Elongation bHLH) is preferentially expressed in the berry at the onset of ripening and during the ripening stage. Overexpression of VvCEB1 in grapevine and tomato affected both grape embryo development and plant organ size by modifying their cell number and cell size. A transcriptional analysis performed on these transgenic lines confirmed that VvCEB1 stimulates cell expansion and suggests the involvement of the phytohormone auxin.VvABF2 is transcriptionally regulated by abscisic acid (ABA), a phytohormone known to play a crucial role in non-climacteric fruit ripening. VvABF2 transcripts accumulated more abundantly during the ripening stage. A whole-genome based transcriptomic approach performed on VvABF2-overexpressing grape cells treated or not with ABA emphasizes the up-regulation of genes linked to fruit ripening processes. Indeed, genes encoding enzymes involved in the biosynthesis of phenolic compounds and in softening were affected. Finally, phenotypic analysis of VvABF2-overexpressing tomato fruits reinforces the link between this transcription factor and fruit softening. Indeed, from the “turning” stage, an accelerated fruit softening was observed in the transgenic fruits.Taken together, this PhD work contributed to a better understanding of the molecular mechanisms involved in the ripening of non climacteric fleshy fruit.

No description available.

La Flavescence dorée est une maladie à phytoplasme incurable qui affecte la vigne. Cette pathologie est uniquement transmise de plante à plante par la cicadelle vectrice Scaphoideus titanus. Malgré l'importance de cette maladie, peu d'études ont été menées sur le vecteur. Ce travail de thèse vise à apporter des connaissances sur la biologie et l'écologie de S. titanus mais aussi de manière plus générale sur l'écologie des insectes phytophages. Trois grands thèmes ont été abordés dans ce mémoire : i) les relations entre l'insecte et son environnement à travers l'influence des températures hivernales sur les œufs en diapause, ii) les relations de l'insecte avec sa plante hôte en examinant l'attractivité de cette dernière et le comportement alimentaire du vecteur, iii) les interactions entre congénères par l'étude du comportement d'agrégation des larves. Les résultats obtenus indiquent que 1) des températures froides ne sont pas indispensables à la levée de diapause mais affectent la protandrie en régulant le sex-ratio opérationnel, 2) l'attractivité de la plante hôte est en grande partie liée à sa couleur et il existe des différences de comportement en fonction du stade de développement, 3) les mâles et les femelles n'ont pas le même comportement alimentaire, ce qui pourrait expliquer leur différentes capacités de vection, 4) l'agrégation des larves ne semble pas due à un recrutement actif de leur part et pourrait contribuer à un transfert horizontal de phytoplasme d'insecte à insecte via la plante. A terme, ces connaissances pourront contribuer à l'élaboration de pistes alternatives à la lutte chimique actuelle contre cette cicadelle dans le cadre d'une réduction des intrants. / The Flavescence dorée is an incurable phytoplasma disease of grapevine. This pathology is exclusively transmitted from plant to plant by the leafhopper vector Scaphoideus titanus. Despite the importance of this disease, few studies have been conducted on the vector. This thesis aims to provide knowledge on the biology and ecology of S. titanus but also more broadly on the ecology of phytophagous insects. Three major themes were addressed in this thesis: i) the relationships between the insect and its environment through the influence of winter temperatures on diapausing eggs, ii) the relationships of the insect with its host plant by examining the attractiveness of the plant and the feeding behaviour of the vector, iii) interactions between congeners in the study of the aggregative behaviour of larvae. Our results indicate that 1) cold temperatures are not essential to break the diapause but contribute to protandry through operational sex ratio regulation, 2) the attractiveness of the host plant is largely due to its colour and different instars exhibit differences in behavioural choices, 3) males and females have different feeding behaviour which may explain their different efficiencies at vection, 4) the aggregation of larvae did not seem to result from active recruitment and could contribute to horizontal insect to insect transfer of phytoplasma through the plant. Such knowledge can contribute to the development of alternative S. titanus pest management techniques.

Las células endoteliales (CE) son responsables de la síntesis y liberación de sustancias vasoactivas ante un estímulo neuronal, hormonal o físico. Procesos patológicos, factores ambientales o el envejecimiento del individuo, dañan las CE y alteran su función. Se denomina disfunción endotelial (DE) a la capacidad disminuída de las CE de inducir vasorrelajación ante el estímulo agonista colinérgico. Los AINEs son fármacos antiinflamatorios, analgésicos y antipiréticos que bloquean la COX. Experimentos preliminares han mostrado que el clonixinato de lisina (Clx), un AINE antranílico, induce DE aguda en anillos de aorta in vitro, por un mecanismo no dilucidado. El extracto de Vitis vinifera (EVv) es rico en flavonoides, compuestos con acción antioxidante. Se intenta determinar si el EVv es capaz de prevenir in vitro la DE inducida por Clx. Se montaron anillos aórticos de ratas en baños termorregulados para la determinación isométrica de fuerza, asignándose al azar en tres grupos: control, grupo 1 (G1) y grupo 2 (G2). El G1 se incubó con 100 µM Clx y el G2 con 5,35 ng/mL EVv junto con 100 µM Clx. Determinamos y comparamos la DE en los anillos aórticos precontraídos con fenilefrina respecto del control. El G1 mostró una notable DE la que fue significativamente (p< 0,05) prevenida por la incubación con EVv. Los resultados obtenidos muestran que el EVv puede prevenir la DE inducida por Clx in vitro. Si bien, se requieren otros experimentos para explicar el mecanismo por el cual Clx induce DE y de prevención del EVv, este fitofármaco se perfila como una alternativa de protección vascular para los pacientes que utilizan crónicamente el Clx.

No description available.