Solanum cernuum Vell. (Solanaceae), popularmente conhecida como \"panacéia\", é uma planta nativa do sul e sudeste do Brasil. Seu nome \"panacéia\" provavelmente é devido à grande amplitude de aplicações que possui na medicina popular: tratamento de úlceras, lesões hepáticas, infecções de pele, como antitumoral, diurético, depurativo, anti-hemorrágico, bem como para o tratamento da gonorreia e da hiperplasia benigna da prostática (HBP). Considerando os usos de S. cernuum na medicina popular brasileira e a escassez de estudos que os corroborrem, propomos neste trabalho, a partir da obtenção de diferentes extratos, frações e compostos isolados, testar as atividades biológicas gastroprotetora, citotóxica e antimicrobiana relatadas na medicina popular. Para tanto, folhas da espécie Solanum cernuum Vell. (Solanaceae) foram coletadas no município de Teresópolis/ RJ. O extrato hidroetanólico (ESC) e em acetato de etila foram obtidos a partir de folhas secas e trituradas. Frações em hexano (FHex), diclorometano (FDCM), acetato de etila (FAcOEt), n-butanol (FBuOH) e água (FAq) foram obtidas a partir do extrato ESC. A partir dos diversos fracionamentos do extrato ESC isolaram-se e identificaram-se quatro compostos: ácido trans-isoferulico, cernumidina, quercitrina e afzelina, sendo encontrados no extrato nas concentrações de 1,5%, 4,8%, 1,3% e 1,6%, respectivamente. Da fração em heptano, obtida da partição do extrato em acetato, isolaram-se ?-sitsterol e friedelina. No ensaio antimicrobiano, apenas as frações FHex, FDCM e FAq, oriundas da partição do extrato ESC, apresentaram atividade, em diferentes concentrações, frente a determinadas linhagens de bactérias e fungos testadas. Quanto aos compostos voláteis, na extração por hidrodestilação, não houve rendimento suficiente, mas a partir do hidrolato, por partição com diclorometano, foi possível determinar a composição dos voláteis por CG/EM. Os tricomas de S. cernuum são majoritariamente estrelados, do tipo tectores. No ensaio do XTT apenas a FDCM e o composto friedelina foram seletivos para células MCF-7 (carcinoma mamário) na concentração de 16,6 ?g/mL e 124,9 ?g/mL, respectivamente. O extrato ESC apresentou atividade gastroprotetora nos ensaios de indução de úlcera por etanol/HCl e por anti-inflamatório não esteroidal (AINE), bem como foi curativo no ensaio de úlcera crônica induzida por ácido acético na dose de 250 mg/kg. Os compostos isolados, exceto o alcaloide cernumidina, apresentaram atividade gastroprotetora pelo ensaio de indução de úlcera por etanol/HCl na dose de 30 mg/kg. Ainda sobre a gastroproteção, na avaliação de pH utilizando o ensaio de ligadura de piloro, todos os grupos de animais tratados com extrato ESC não apresentaram diminuição da acidez estomacal. Porém, houve diminuição da concentração de íons hidrogênio ([H+] mEq.g-1/L) na secreção gástrica nos grupos tratados. A produção de muco na mucosa gástrica também não foi aumentada nos grupos tratados com o extrato ESC. A avaliação da ação gastroprotetora por inibição da enzima iNOS e alquilação de grupos sulfidrilas evidenciou que a produção de óxido nítrico e de grupos sulfidrilas podem estar envolvidos na atividade gastroprotetora do ESC. Diferentes concentrações de ii extrato ESC e alcaloide cernumidina foram testadas nos tempos de 48, 72 e 96 h em cultura primária de células de músculo liso relacionadas a hiperplasia benigna da próstata (HPB), sendo possível observar inibição do crescimento celular de 60% na concentração de 3 mg/mL para o extrato e de 62% para o alcaloide na concentração de 1 mg/mL (3,3 x 10-6 M) no tempo de exposição de 96 h. Com o intuito de avaliar o potencial efeito indutor de apoptose, foi realizado o ensaio de anexina V Cy5 por citometria de fluxo. Tanto para o extrato ESC como para o acaloide cernumidina observou-se que a morte celular ocorreu mais por apoptose. Apenas para o alcaloide, na concentração de 1 mg/mL, houve significativa morte por necrose. Na atividade de inibição da angiogenese, avaliada em células HUVEC, a FBuOH (50 ?g/mL) e o alcaloide cernumidina (160 nM) inibiram a formação de vasos endoteliais em 62,75% e 77,73%. Na secagem do extrato por spray dryer o rendimento, a densidade aparente, a densidade compacta, o tamanho das partículas (D50) e o teor de cernumidina foram influenciados por alguns dos fatores avaliados: temperatura, vazão e porcentagem de adjuvante, linearmente ou na forma quadrática. Na otimização da secagem por spray dryer, utilizando a função desejabilidade, observou-se a proximidade dos valores preditos para rendimento do pó e teor de cernumidina com os valores reais, evidenciando a confiabilidade desse método matemático. Assim, os resultados obtidos corroboram alguns dos usos populares abrindo novas possibilidades para o desenvolvimento de fitoterápico a partir S. cernuum. / Solanum cernuum Vell. (Solanaceae), popularly known as \"panacéia\", is a native tree from Southern and Southeastern Brazil. Its traditional name is due to the wide range of uses in folk medicine including the treatment of ulcers, liver damage, skin infections, as diuretic, antitumor, depurative, anti-hemorrhagic, as well as to treat gonorrhoea and benign prostatic hyperplasia (BPH). Considering the importance of S. cernuum in folk medicine and the lack of research supporting its use, the aims of this project were to obtain different extracts, fractions and isolated compounds this plant to be tested for gastroprotective, cytotoxicity and antimicrobial activities. Leaves S. cernuum were collected in Teresópolis/RJ. The hydroethanolic (ESC) and ethyl acetate extracts were obtained from the dried and grinded leaves. Fractions in hexane (FHex), dichloromethane (FDCM), ethyl acetate (FAcOEt), n-butanol (FBuOH) and water (FAQ) were obtained from the ESC extract. The ESC extract was fractionated using different chromatographic techniques furnishing four isolated compounds: trans-isoferulic acid, cernumidine, quercitrin and afzelin. The content of these four compounds were quantified to be 1.5%, 4.8%, 1.3% and 1.6%, respectively, in the extract. ?-sitosterol and the friedelin were isolated by partitioning the ethyl acetate extract with heptane. In the antimicrobial assay, only FHex, FDCM and FAq fractions showed activity at different concentrations against the tested strains of bacteria and fungi. The hydrodistillation of the leaves of S. cernuum did not fusrnish essential oils, but the partition of the hydrolate with dichloromethane allowed the determination of its composition by GC/MS. The trichomes of S. cernuum are majority kind of stellate tector. Only FDCM fraction and friedelin compound showed activity in XTT assay against MCF-7 cells (breast carcinoma) at the concentration of 16.6 ?g/mL and 124.9 ?g/mL, respectively. The ESC extract showed gastroprotective effects in the acute gastric ulcer assay, which is induced by HCl/EtOH and nonsteroidal anti-inflammatory drugs (NSAIDs). Also, in the chronic ulcer assay, induced by acetic acid, the oral administration of ESC extract (250 mg/kg) reduced the ulcerated area, suggesting that it has a curative potential. The isolated compounds (30 mg/kg) exhibited gastroprotective activity in acute gastric ulcer assay, except cernumidine. The results indicated that the ESC extract was able to reduce the concentration of H+ ions in comparison with the control group. However, ESC extract did not modify the pH of the gastric juice acid and there was no significant increment in the amount of gastric adherent mucus in pretreated group. Further, it was evaluated the role of nitric oxide (NO) and sulfhydryl (SH) groups on the gastroprotective effect elicited by ESC extract. The results showed that gastroprotection induced by the ESC extract is correlated with the presence of endogenous NO and SH groups which were responsible for gastroprotective activity. In the anti-angiogenic activity assay evaluated in HUVEC cells, the FBuOH fraction (50 ?g/mL) and the cernumidine alkaloid (160 nM) inhibited the the formation of endothelial vessels by 62.75% and 77.73%, respectively. Different concentrations of the ESC extract and cernumidine alkaloid were further tested in primary culture of iv smooth muscle HPB for 48, 72 and 96 h. ESC extract (3 mg/mL) and the alkaloid (1 mg/mL; 3.3 x 10-6 M) treatment for 96 h inhibited the cell growth by 60% and 62%, respectively. In addition, it was assessed the potential effect of extract and its constituents to induce apoptosis by performing the annexin Cy5 assay by flow cytometry. Treatment with ESC extract and cernumidine alkaloid led to cell death by apoptosis. Only cernumidine at 1 mg/mL showed significant cells death by necrosis compared to control. Considering the spray dryer technique to dry the extract, the yield, bulk and tapped densities, particle size (D50) and the content of the cernumidine are influenced by some of the evaluated factors: temperature, flow and excipient percentage, linearly or quadratic form. To optimize the drying by spray dryer, it was used the desirability function. It was observed that the proximity of the predicted values of the yield and cernumidine content with the real values were found, showing the reliability of this mathematical method. Therefore, the obtained results corroborate the folk use and open new opportunities for the development of a phytotherapic from S. cernuum.

Die Tomate ist weltweit eines der am meist konsumierten Gemüse, doch der hohe Verzehr erhöht auch das Risiko einer allergischen Reaktion. Zu den Allergenen zählen viele Proteine der Pflanzenabwehr, welche durch verschiedenste biotische und abiotische Stressoren induziert werden. Allerdings ist bis heute der Einfluss biotischer Faktoren auf die Allergenität von Obst und Gemüse weitestgehend unbekannt. Diese Dissertation befasst sich mit den Auswirkungen der symbiontischen Mykorrhiza und des pathogenen Pepino Mosaikvirus auf die Allergenität von Tomaten. Früchte von mykorrhizierten Tomatenpflanzen wiesen eine höhere Expression allergenkodierender Gene auf als die nicht mykorrhizierten Kontrollen, allerdings übertrug sich dies nicht auf die Allergenität der Tomaten. Pepino Mosaikvirus-infizierte Tomatenpflanzen zeigten keine generelle Aktivierung der Allergenexpression und auch keine erhöhte Allergenität. Aufgrund großer individueller Reaktionsunterschiede der Probanden in den klinischen Allergietests konnten einzeln auftretende Unterschiede nicht über die Gesamtheit der getesteten Allergiker abgesichert werden. Die individuellen Reaktionen der Probanden konnten wiederum nicht auf die Anzahl und Identität der Allergene von Tomatenpflanzen mit unterschiedlichen genetischen Hintergründen oder aus verschiedenen Anbauweisen zurückgeführt werden. Während der Experimente wurden 13 neue putative Tomatenallergene identifiziert unter denen das Cyclophilin rekombinant in Escherichia coli hergestellt und seine allergene Aktivität bestätigt wurde. Schlussfolgernd nahmen biotische Faktoren keinen nennenswerten Einfluss auf die Allergenität von kommerziell angebauten Tomaten. Über dies hinaus wurden neue Erkenntnisse über persistente Virus-Pflanzen Interaktionen gewonnen. Schließlich konnte die Liste der putativen Tomatenallergene um einige Kandidaten erweitert werden, von denen das Cyclophilin als Allergen bestätigt wurde. / Tomatoes are now among most consumed vegetables worldwide; unfortunately accompanied by an increasing risk of allergic reactions. Pathogenesis-related proteins can act as allergens and are induced by various biotic and abiotic stresses. Up to now nearly nothing is known about the impact of biotic factors on allergenic potentials. This thesis investigates the allergenicity of symbiotically mycorrhized and Pepino mosaic virus-infected tomato fruits. Although induced allergen-encoding gene expression was detected in the fruits of mycorrhizal tomato plants, there was no impact on allergenicity. In contrast, general induction of defence-related allergens in Pepino mosaic virus-infected tomato fruits was not observed. Consequently, clinical allergy tests did not reveal any generally increased allergenic potential of Pepino mosaic virus-infected tomato fruits. High inter-individual differences in clinical allergy tests made it difficult to make statistically confirmed statements about the allergenicity of colonised tomato fruits. However, the hypothesis that such individual variability is based on differential reactions of individual subjects to particular allergens in tomato fruits, from plants with certain genetic backgrounds or cultivated under distinct conditions, had to be rejected. During these investigations, 13 new putative tomato allergens were identified. One of the candidates, cyclophilin, was recombinantly produced in Escherichia coli and its allergenic activity was confirmed in different clinical allergy tests with tomato-allergic subjects. In conclusion, this study demonstrates that biotic factors are only of minor importance for the allergenic potential of commercially produced tomatoes. Moreover, the experiments revealed new insights into persistent plant-virus interactions. In particular, these extended the list of putative tomato allergens to include new candidates, and confirmed the allergenic activity of one of these, namely cyclophilin.

Tomato (Solanum lycopersicum L.) consumption has increased every year due to the fruit attractiveness, several utilizations, and beneficial effects for human health. However, tomato fruits can accumulate a Cd concentration that exceeds the safety threshold for human consumption of vegetables, even when plants are grown in soil with acceptable Cd level. Cd is a non-essential, hazardous element to biological systems, triggering several diseases in humans. In plants, Cd disturbs the antioxidant machinery, changes the nutritional status, and impairs the photoassimilate production and/or partitioning, hence reducing fruit yield and quality. However, distinct tomato accessions can present contrasting tolerance degree to Cd toxicity, as detected by our group in previous studies. The use of these accessions is a powerful approach to identify strategies employed by plants to cope with Cdinduced challenges, and the acknowledgement of such strategies can be potentially used in breeding and biotechnological programs to improve fruit yield and quality in crops that were cultivated in contaminated fields. The set of studies that compose the present thesis aimed (i) to identify the main mechanisms for the contrasting tolerance degree to Cd-induced toxicity in tomato accessions after short and long-term Cd exposure; (ii) to evaluate the relationship among tolerance degree and fruits attributes in plants that were grown in Cd-containing soil, and (iii) to determine the transgenerational effects of Cd-induced stress. In the first experiment, nine tomato accessions with a varied tolerance degree, which was based on biomass accumulation, to Cd exposure were grown in hydroponic solution containing CdCl2 35 μM for 6 days. Avoidance of high Mg concentration in roots was identified as a plant strategy to mitigate Cd toxicity by preventing formation of root hairs. Regarding the mode of action of Cd toxicity, Mn excess in leaves, in addition to the high Cd concentration per se, seems to be coupled to leaf damages that are enhanced by the increased Zn and B concentrations in the photosynthetic tissues. In the second experiment, tolerant (Yoshimatsu) and sensitive (Tropic Two Orders) genotypes were grown in Cd-containing soil, in order to evaluated production parameters. After plant exposure to Cd, the tolerant genotype presented an increased fruit diameter, height and weight, when compared to the control plants. In both cultivars, Cd concentration varied according to the following descending order: roots = leaf blade > (floral receptacle, peduncle and sepals) > stem = fruit peel = fruit pulp. Moreover, data suggested that floral receptacle and its related-structures acted as a barrier to the Cd transportation to the fruits, but it was not enough to avoid Cd reaching the fruits. Furthermore, Cd exposure provoked remarkable reductions in the Mg concentration in roots of sensitive and tolerant genotypes, revealing that both tomato cultivars are able to employ this mechanism for plant acclimation to long-term Cd exposure. Considering such information, it is possible that, under the short-term Cd exposure, tolerant accessions activate this mechanism either early or faster than sensitive genotypes. In addition, positive transgenerational effects on seed germination and vigor of the tolerant genotype were triggered by the plant-mother cultivation in Cd-containing media, despite of the increased chromosomal abnormality. This work reported new insights about the effects of Cd exposure on tomato development, tolerance mechanisms, fruit quality and yield of tomato, as well as Cd distribution in the plants. / O consumo de tomate (Solanum lycopersicum L.) tem aumentado a cada ano devido a atratividade dos frutos, suas diversas utilizações e efeitos benéficos para a saúde humana. No entanto, os frutos de tomate podem acumular uma concentração de cádmio (Cd) que excede o limiar de segurança para o consumo humano, mesmo quando as plantas são cultivadas em solo com níveis aceitáveis de Cd. Cádmio e um elemento não-essencial, extremamente perigoso para os sistemas biológicos, desencadeando varias doenças em seres humanos. Nas plantas, o Cd perturba a maquinaria antioxidante, altera o estado nutricional e prejudica a produção e /ou o particionamento de fotoassimilados, frequentemente reduzindo a produtividade e qualidade de frutos. No entanto, diferentes acessos de tomateiros podem apresentar contrastantes graus de tolerância a toxicidade gerada pela exposição ao Cd, como detectado em estudos anteriores de nosso grupo. O uso desses acessos e uma abordagem poderosa para identificar as estratégias empregadas pelas plantas para lidar com os desafios induzidos pelo Cd; e o conhecimento de tais estratégias pode ser potencialmente utilizado em programas biotecnológicos e de melhoramento genético. Deste modo, o conjunto de estudos que compõem a presente tese objetivou (i) identificar os principais mecanismos que suportam o grau de tolerância contrastante a toxicidade induzida por Cd em acessos de tomate após exposição a curto e longo prazos a este metal pesado; (ii) avaliar a relação entre o grau de tolerância e os atributos físico-químico de frutos oriundos de tomateiros cultivados em solo contendo Cd, e (iii) determinar os efeitos transgeracionais do estresse induzido por Cd. No primeiro experimento, nove acessos de tomateiro com graus variados de tolerância a exposição ao Cd, baseado na acumulação de biomassa, foram cultivados em solução hidropônica contendo 35 μM de CdCl2 durante 6 dias. O impedimento de elevada concentração de magnésio (Mg) em raízes foi identificado como possível estratégia da planta para mitigar a toxicidade de Cd, por meio da evitação da formação de pelos radiculares. Em relação ao modo de ação da toxicidade induzida por Cd, o excesso de Mn, em adição a elevada concentração de Cd, parece estar acoplado aos danos foliares que são acentuados ainda mais pelas altas concentrações de zinco (Zn) e boro (B) nos tecidos fotossintéticos de plantas sob exposição ao Cd. No segundo experimento, os genótipos tolerantes (Yoshimatsu) e sensíveis (Tropic Two Orders) foram cultivados em solo contendo Cd, a fim de avaliar os parâmetros de produção. O genótipo tolerante apresentou frutos com maior diâmetro, altura e peso após o cultivo em solo contendo Cd, quando comparado as plantas controle. Em ambas as cultivares, a concentração de Cd variou de acordo com a seguinte ordem descendente: raízes = folíolos> (receptáculo floral, pedúnculo e sépalas) > caule = casca de fruta = polpa de fruta. Alem disso, dados sugerem que o receptáculo floral e suas estruturas atuaram como uma barreira ao transporte de Cd para os frutos, entretanto, ela não foi suficiente para evitar que o Cd atingisse os frutos. Em adição, a exposição ao Cd provocou notáveis reduções na concentração de Mg nas raízes de genótipos sensíveis e tolerantes, revelando que a aclimatação das plantas depende do baixo status de Mg em tecidos radiculares. Desde que ambas as cultivares são capazes de empregar este mecanismo, os dados sugerem que, durante a exposição a curto prazo ao Cd, acessos tolerantes são capazes de ativa-lo ou mais cedo ou mais rápido do que acessos sensíveis. Ademais, efeitos transgeracionais positivos na germinação e vigor das sementes do genótipo tolerante foram desencadeados pelo cultivo planta-mãe em solo com Cd, apesar do aumento de anormalidades cromossômicas. Este trabalho reportou novos conhecimentos sobre os efeitos da exposição ao Cd sobre o desenvolvimento do tomateiro, mecanismos de tolerância, qualidade e rendimento de frutos, bem como a distribuição de Cd dentro da planta.

Dans son environnement, la plante interagit sans cesse avec des microorganismes. Elle est confrontée à une variété de microorganismes bénéfiques, neutres ou pathogènes, qui sont fortement dépendants des ressources carbonées que la plante libère dans le sol, leur conférant ainsi un apport de nutriments et d’énergie nécessaire à leur développement. La mycorhize à arbuscules est une symbiose mutualiste formée par 80% des plantes terrestres datant de l’Ordovicien, i.e. environ 450 millions d’années avant notre ère. L’ensemble des travaux de recherche présenté au sein de ce manuscrit, s’inscrit dans le cadre de deux objectifs généraux : (i) acquérir une meilleure compréhension des mécanismes à l’origine des relations trophiques chez la plante mycorhizée, et (ii) étudier l’impact de la mycorhization sur la production végétale tant en terme de quantité que de qualité. Nous avons étudié la réponse à la mycorhization de variétés anciennes de blé afin d’appréhender s’il existait une différence dans un environnement semi-contrôlé (serres) ou dans un environnement non contrôlées (champ), et/ou en fonction de la communauté de champignons mycorhiziens à arbuscules présente. Nos résultats ont mis en évidence que la mycorhization et la nature des champignons mycorhiziens arbusculaires endogènes peuvent influer sur le rendement au stade tallage, même chez des variétés de blé ayant une faible capacité mycorhizogène. Nous avons aussi illustré l’importance de bien choisir les critères utilisés pour mesurer ce gain éventuel. Dans un deuxième axe de recherche nous nous sommes intéressés à l’impact de la mycorhize à arbuscules sur le développement de la tomate Micro-Tom, et les échanges trophiques au cours de l’interaction. Nous avons pu mettre en évidence, grâce à une analyse multivariée, à la fois des différences de comportement parmi les plantes particulièrement aux stades fruit vert mature et fruit rouge mature selon la nature des champignons mycorhiziens à arbuscules présents, et des potentiels phénomènes d’interaction entre deux souches de champignons mycorhiziens à arbuscules; nos résultats confirmant que les arbuscules ne sont pas les seules sites d’échanges dans la mycorhize à arbuscules. Le troisième axe de ce travail a porté sur l’impact potentiel des méthodes de production de semences de variétés anciennes de tomate en condition de sécheresse, à la fois sur la communauté endogène de champignons mycorhiziens au champ, sur la tolérance de la plante au stress hydrique et sur la production végétale en terme de rendement et de qualité des fruits. Le site d’expérimentation se situait au Potager de santé (ferme de production de semences gérée par Pascal Poot). Nos résultats ne montrent aucune différence, en conditions de stress hydrique au champ, entre des variétés cultivées régulièrement sur ce site et des variétés commerciales. Alors, on peut se demander si d’autres facteurs liés au site d’exploitation, tels que les microorganismes interagissant avec les racines de la plante pourraient être à l’origine de la tolérance accrue au stress hydrique. Des travaux sont en cours au laboratoire pour étudier cette hypothèse. L’ensemble de ces travaux ouvrent la voie à de nouvelles recherches visant à élucider les mécanismes moléculaires impliqués dans la régulation des échanges trophiques au cours de la mycorhize à arbuscules et à la valorisation des services écosystémiques rendus par la mycorhize à arbuscules au champ. / In its environment, the plant interacts constantly with microorganisms. It is confronted with a variety of beneficial, neutral or pathogenic microorganisms, which are highly dependent on the carbon resources that the plant releases into the soil, giving them a supply of nutrients and energy necessary for their development. The arbuscular mycorrhiza is a mutualistic symbiosis formed by 80% of terrestrial plants from the Ordovician period, i.e. about 450 million years ago. The research presented in this manuscript was focused on two main goals: (i) to gain a better understanding of the mechanisms underlying trophic relationships in the mycorrhizal plant, and (ii) to study the impact of mycorhization on plant production, both in terms of quantity and quality. We investigated the mycorrhizal response of wheat landraces in order to understand if there were differences in a semi-controlled environment (greenhouses) or in an uncontrolled environment (field), and / or depending on the community of mycorrhizal fungi. Our results showed that mycorrhization and the nature of endogenous arbuscular mycorrhizal fungi can affect yield, even in wheat varieties with low mycorrhizal ability. We also highlighted the importance of choosing the criteria used to measure this potential gain. In a second line of research, we were interested in the impact of arbuscular mycorrhiza on the development of Micro-Tom tomato, and the trophic exchanges during the interaction. Multivariate analysis revealed behavioral differences between plants at mature green fruit and red ripening stages depending on arbuscular mycorrhizal fungal strain, as well as potential interaction event between two arbuscular mycorrhiza fungus trains. Our results confirm that the arbuscules are not the only sites of exchange in arbuscular mycorrhiza. The third axis of this work focused on the potential impact of seed production methods of ancient tomato varieties in drought condition, both on the endogenous community of arbuscular mycorrhizal fungi in the field, on the tolerance of the plant to water stress and on crop production in terms of fruit yield and quality. The experimental site was located in the Potager de santé (seed farm managed by Pascal Poot). Our results show no difference, under conditions of water stress in the field, between varieties regularly cultivated on this site and commercial varieties. Then, one may wonder if other factors related to the exploitation site, such as the beneficial microorganisms interacting with the roots of the plants could be at the origin of the increased tolerance to water stress. Work is underway in the laboratory to study this hypothesis. All of this work paves the way for new research aimed at elucidating the molecular mechanisms involved in the regulation of trophic exchanges during arbuscular mycorrhizae and the valuation of the ecosystem services rendered by arbuscular mycorrhizae in the field.

Atualmente, o HLB é considerado a principal doença que acomete as plantas cítricas. Diante desse fator, pesquisas por cultivares resistentes a esta doença são necessárias. A transformação genética via Agrobacterium, juntamente com o uso de plantas modelos, tem sido uma alternativa para verificação do funcionamento dos genes em resposta a patógenos, isto porque as plantas modelos possuem como característica ciclo de vida curto e alto poder de regeneração. Assim sendo, objetivou-se com o presente trabalho, a transformação genética via Agrobacterium tumefaciens, de tomate Micro-Tom (Solanum lycopersicum L.) e de laranja doce, com os genes que codificam as proteínas PR-8 e CDR-1, isolados a partir de Citrus simensis. Os cotilédones provenientes de sementes germinadas in vitro de tomate Micro-Tom foram utilizados como fonte de explante para os experimentos de transformação genética com os genes PR-8 e CDR-1. Esses explantes foram subcultivados até o aparecimento de brotos regenerantes e posteriormente plantas transgênicas, as quais foram aclimatizadas e levadas a casa-de-vegetação. A transgenia foi confirmada por PCR e o número de inserções do gene por Southern blot. As plantas foram cultivadas até a obtenção da geração T1. Simultaneamente, foram realizados experimentos de transformação genética em segmentos de epicótilo, provenientes de sementes de laranja ‘Hamlin’ germinadas in vitro, com o gene CDR-1, a fim de se obter plantas transgênicas e sua caracterização. Paralelamente, foi realizada a construção da curva padrão pela análise de qPCR para identificação de Pseudomonas syringae pv. tomato. Foram obtidas treze plantas transgênicas de tomate Micro-Tom com o gene PR-8 e três com o gene CDR-1. As eficiências de transformação foram em torno de 0,38 a 1,98%. Três plantas de tomate Micro-Tom transgênicas com o gene PR-8 foram caracterizadas por Southern blot e o número de inserções variou de 1 a 3. Dezenove plantas transgênicas de laranja ‘Hamlin’ com o gene CDR-1 foram obtidas através dos experimentos de transformação genética. A eficiência de transformação foi de 2,06 a 5,96%. Dessas, apenas uma foi caracterizada por Southern blot apresentando 1 número de cópia do DNA no genoma da planta. / HLB is currently considered the main disease affecting citrus plants. Given this factor, research for cultivars resistant to this disease is needed. Genetic transformation via Agrobacterium with the use of model plants has been an alternative for checking the gene function in response to pathogens, because these model plants have as characteristic a short life cycle and high power of regeneration. Therefore, the aim of this work was to produce transgenic plants, via Agrobacterium tumefaciens, of Micro-Tom tomato (Solanum lycopersicum L.), and sweet orange, with the genes encoding the PR-8 and CDR-1 proteins isolated from Citrus sinensis. The cotyledons from in vitro germinated Micro-Tom tomato seeds were used as explants source for genetic transformation experiments with PR-8 and CDR-1 genes. These explants were subcultured until the appearance of regenerating shoots and after transgenic plants, which were acclimatized and taken to a greenhouse. The transgenic plants were confirmed by PCR and the number of gene insertions by Southern blot. The plants were grown until T1 generation was obtained. Simultaneously genetic transformation experiments were performed with epicotyl segments from \'Hamlin\' sweet orange seeds germinated in vitro with CDR-1 gene in order to obtain transgenic plants and their characterization. Simultaneously, the standard curve construction was performed by qPCR analysis for identification of Pseudomonas syringae pv. tomato. Thirteen transgenic plants of Micro-Tom tomato with PR-8 gene and three with CDR-1 gene were obtained. The transformation efficiencies were around 0,38 to 1,98%. Three transgenic plants of Micro-Tom tomato with PR-8 gene were characterized by southern blot, and the number of inserts ranged from 1 to 3. Nineteen transgenic \'Hamlin\' sweet orange plants with CDR-1 gene were obtained through genetic transformation experiments, and the transformation efficiency was 2,06 to 5,96%. One plant was characterized, by Southern blot and has one DNA copy number in the plant genome.

Chez les végétaux supérieurs, l’embryogenèse est une phase clé du développement au cours de laquelle l’embryon établit les principales structures qui formeront la future plante et synthétise et accumule des réserves définissant le rendement et la qualité nutritionnelle des graines. Ainsi, la compréhension des évènements moléculaires et physiologiques menant à la formation de la graine représente un intérêt agronomique majeur. Toutefois, l'analyse des premiers stades de développement est souvent difficile parce que l'embryon est petit et intégré à l'intérieur du tissu maternel. Solanum chacoense qui présente des fleurs relativement grande facilitant l’isolation des ovules, a été utilisée pour l’étude de la biologie de la reproduction plus précisément la formation des gamètes femelles, la pollinisation, la fécondation et le développement des embryons. Afin d'analyser le programme transcriptionnel induit au cours de la structuration de ces étapes de la reproduction sexuée, nous avons mis à profit un projet de séquençage de 7741 ESTs (6700 unigènes) exprimés dans l’ovule à différents stades du développement embryonnaire. L’ADN de ces ESTs a été utilisé pour la fabrication de biopuces d’ADN. Dans un premier temps, ces biopuces ont été utilisé pour comparer des ADNc issus des ovules de chaque stade de développement embryonnaire (depuis le zygote jusqu’au embryon mature) versus un ovule non fécondé. Trois profils d’expression correspondant au stade précoce, intermédiaire et tardive ont été trouvés. Une analyse plus approfondie entre chaque point étudié (de 0 à 22 jours après pollinisation), a permis d'identifier des gènes spécifiques caractérisant des phases de transition spécifiques. Les annotations Fonctionnelles des gènes differentiellement exprimés nous ont permis d'identifier les principales fonctions cellulaires impliquées à chaque stade de développement, révélant que les embryons sont engagés dans des actifs processus de différenciation. Ces biopuces d’ADN ont été par la suite utilisé pour comparer différent types de pollinisation (compatible, incompatible, semi-compatible et inter-espèce) afin d’identifier les gènes répondants à plusieurs stimuli avant l'arrivé du tube pollinique aux ovules (activation à distance). Nous avons pu démontrer que le signal perçu par l’ovaire était différent et dépend de plusieurs facteurs, incluant le type de pollen et la distance parcourue par le pollen dans le style. Une autre analyse permettant la comparaison des différentes pollinisations et la blessure du style nous a permis d’identifier que les programmes génétiques de la pollinisation chevauchent en partie avec ceux du stress. Cela était confirmé en traitant les fleurs par une hormone de stress, méthyle jasmonate. Dans le dernier chapitre, nous avons utilisé ces biopuces pour étudier le changement transcriptionnel d’un mutant sur exprimant une protéine kinase FRK2 impliqué dans l’identité des ovules. Nous avons pu sélectionner plusieurs gènes candidat touchés par la surexpression de cette kinase pour mieux comprendre la voie se signalisation. Ces biopuces ont ainsi servi à déterminer la variation au niveau transcriptionnelle des gènes impliqués lors de différents stades de la reproduction sexuée chez les plantes et nous a permis de mieux comprendre ces étapes. / In higher plants, embryogenesis is a key phase of development during which the embryo establishes the main structures that will form the future plant, synthesizes, and accumulates the reserves that will define the yield and nutritional quality of the seeds. Thus, understanding the molecular and physiological events leading to the formation of the seed is of major agronomic interest. However, analysis of early stages of development is often difficult because the embryo is small and integrated within the maternal tissue. Solanum chacoense, whose relatively large flowers facilitate the isolation of ovules, was used to study the biology of reproduction, in particular the formation of female gametes, pollination, fertilization and embryo development. To analyze the transcriptional program induced during these stages of sexual reproduction, we produced amplicon-derived microarrays with 7741 ESTs isolated from ovules bearing embryos from different developmental stages. These chips were first used to compare cDNA of unfertilized ovule with ovule cells of each stage of embryonic development (from zygote to mature embryo). During embryogenesis, three major expression profiles corresponding to early, middle and late stages of embryo development were identified. Further analysis, of time points taken every 2 days from 0 to 22 days after pollination allowed the identification of a subset of stage-specific and transition-specific genes. Functional annotation of differentially expressed genes allowed us to identify the major cell processes implicated at each stage of development and revealed that embryos are engaged in active differentiation. The DNA microarrays were then used to compare different types of pollination (compatible, incompatible, semi-compatible and inter-species) to identify genes responding to various stimuli before the pollen tube reach the ovules (activation at distance). We found that the signal received by the ovary was different and depended on several factors including the pollen source and the distance traveled by the pollen in the style. Another analysis comparing different pollinations with wounding of the style showed that the genetic programs of pollination overlap with those of stress. This was confirmed by treating the flowers with a stress hormone, methyl jasmonate. lastly, we used the microarrays to study transcriptional changes in mutant ScFRK2. The over expression of FRK2 affect the ovule identity. We were able to select several candidate genes that may have a role in ovules identity signaling. These chips were used to determine the variation in transcription of genes involved at various stages of sexual reproduction in plants and has allowed us to better understand these steps at the transcriptional level.

A produção de hortaliças em substratos é uma técnica de cultivo que pode aumentar a produtividade, economizar recursos e facilitar o manejo nutricional das plantas. Contudo, para que isso seja possível, deve-se conhecer os fatores que afetam o crescimento das plantas cultivadas nesse sistema. O objetivo deste trabalho foi avaliar os efeitos de diferentes doses de nitrogênio da solução nutritiva (SN) (60, 80 100, 120 e 140% da dose padrão) em dois tipos de substratos (S1: fibra de coco e S2: a base de casca de pinus) no cultivo de minitomate Sweet Grape. Foram avaliadas ao longo do ciclo de cultivo o pH, a condutividade elétrica (CE) e o teor de nitrato (NO3-drenado) e potássio (K+drenado) na solução drenada dos vasos, o índice SPAD e o teor de nitrato (NO3- pecíolo) e potássio (K+ pecíolo) da seiva do pecíolo das folhas e o teor de nitrogênio da massa seca das folhas (Nfolha). Foram determinados o número de cacho por planta (NCPP) e o comprimento médio das hastes (CMH). Os frutos colhidos foram classificados, contados e pesados para a obtenção da massa média dos frutos grandes (MMFG), médios (MMFM) e pequenos (MMFP), massa total de frutos por planta (MTFPP), massa total de frutos grandes (MTFG), médios (MTFM), pequenos (MTFP) e rachados (MTFRA), número total de frutos por planta (NTFPP), número total de frutos grandes (NTFG), médios (NTFM), pequenos (NTFP) e rachados (NTFRA). Amostras de frutos foram coletadas em três períodos e avaliadas quanto ao teor de sólidos solúveis (TSS), acidez titulável (AT) e concentração de ácido ascórbico (AA). Os valores de pHdrenado diminuíram com o aumento das doses de N da solução nutritiva. Os efeitos do N no pHdrenado se intensificaram ao longo do ciclo de cultivo em razão do acúmulo de sais no meio radicular, principalmente no S1. A CEdrenada aumentou com dose de N e foi maior no S2. O aumento da dose de N elevou os teores de NO3-drenado em ambos os substratos. O K+drenado foi superior na dose de 140% de N no S1. Os valores de índice SPAD e Nfolha aumentaram com a elevação das doses de N da solução nutritiva e reduziram ao longo do ciclo de cultivo. O NO3-pecíolo elevou com o aumento da dose de N da SN. A MMFG foi superior com a adição de 140% de N em relação à dose de 60%. O aumento da dose de N elevou o NTFG, NTFM, NTFP, NTRA e NTFPP. O maior NTFG foi obtido no S2 enquanto que o maior NTFPP, NTFP e NTFRA ocorreu no S1. A MTFG, MTFM, MTFP, MTFRA e MTFPP aumentaram com o aumento da dose de N. Os valores mais elevados de MTFG e MTFP foram obtidos na dose de 140% de N, 331,05 e 1.249,82 g planta-1, respectivamente. A maior MTFM foi obtida na dose de 120% de N, não diferindo, porém, das doses de 100 e 140% de N. O TSS, a AT e o AA dos frutos não foram influenciados pelas doses de N e tipos de substrato. / Vegetables production in soilless media is a technique that can increase yield, saving resources and facilitate the nutritional management of plants. However, for that to be possible, its necessary to know how the factors affect the plants growth in this system. The aim of this study was to evaluate the effects of different nitrogen rates of nutrient solution (NS) (60, 80 100, 120 and 140% of the standard) in two type of soilless media (S1: coconut fiber and S2: pine bark as base) for the mini tomato Sweet Grape growth. Were evaluated during the growing season pH, electrical conductivity (EC) and the nitrate content (NO3-drained) and potassium (K+ drained) in the solution drained from the vessels, SPAD index and the nitrate (NO3-pecíolo) and potassium (K+ petiole) content on petiole sap from the leaves and the nitrogen content in leaf dry mater (Nleaf). Were determined the number of fruit per plant (NFPP) and the average length of stems (ALS). The harvested fruits were sorted, counted and weighed to obtain the average mass of large fruits (AMLF), medium fruits (AMMF) and small fruits (AMSF), total weight of fruits per plant (TWFPP), total weight of large fruits (TWLF) medium fruits (TWMF), small fruits (TWSF) and cracked fruits (TWCF), total number of fruits per plant (TNFPP), total number of large fruits (TNLF), medium fruits (TNMF), small frutis (TNSF) and cracked fruits (TNCF). Fruit samples were collected in three periods and evaluated for soluble solids (SS), titratable acidity (TA) and concentration of ascorbic acid (AA). The pHdrained values decreased with increasing N levels in nutrient solution. The effects of N on pHdrained intensified throughout the growing season due to the accumulation of salts in the root medium, especially in S1. The CEdrained increased with N rate and was higher in S2. The increase in N rate increased the levels of NO3-drained on both substrates. The K+ drained was higher at 140% N dose in S1. SPAD index and Nleaf values increased with higher N rates in nutrient solution and reduced throughout the growing season. The NO3 - petiole increased with increasing dose of N in NS. The MMFG was higher with the addition of 140% N in relation to the dose of 60%. The increase in N rate increased the TNLF, TNMF, TNSF, TNCF and TNFPP. The biggest TNLF was obtained in S2 while the largest TNFPP, TNSF and TNCF occurred in S1. The TWLF, TWMF, TWSF, TWCF and TWFPP increased with increasing N levels in NS. The highest values of TWLF and TWSF were obtained at 140% N level, 331.05 and 1249.82 g plant-1, respectively. The biggest TWMF was obtained at 120% N level in NS, however, not differing of the 100 and 140% N levels. The SS, TA and AA fruits were not influenced by N and substrate types.

Usualmente a bataticultura no Brasil migra para novas áreas devido à alta ocorrência de doenças de solo, onde seu cultivo é realizado anualmente após a cultura do milho (Zea mays) com preparo de solo feito com grade aradora, implemento cujo uso frequente gera impedimentos físicos em subsuperfície. Atualmente, é limitado o esforço de pesquisa sobre sistemas sustentáveis baseados no baixo uso de insumos externos que minimizem impactos prejudiciais ao ambiente. Desse modo, o preparo profundo de solo em sucessão a poáceas, constitui uma alternativa viável a qual pode levar os produtores a manter altos níveis de produção e boa qualidade dos tubérculos, sem que seja necessária a mudança da área plantada. O presente estudo teve o objetivo de comparar dois sistemas de preparo de solo (preparo convencional e preparo profundo) para a cultura da batata (Solanum tuberosum L.) cv. Atlantic, em sucessão a poáceas, quanto aos atributos do solo, produtividade e dinâmica do crescimento da batateira. O experimento foi conduzido por um ano com inicio em setembro de 2011 em área do Departamento de Produção Vegetal, ESALQ/USP, situada na latitude 22°42\'09\'\' S e na longitude 47°38\'01\'\' W a 569 m de altitude. Foram estudadas quatro sucessões de poáceas com batata, sendo os tratamentos: T1: sucessão Panicum maximum cv. Tanzânia - batata, sob preparo profundo (Tanzânia PP), T2: sucessão Brachiaria brizantha cv. Marandu - batata, sob preparo profundo (Braquiária PP) e T3: sucessão milho (Zea mays cv. AG 6080) - batata, sob preparo profundo (Milho PP). Para efeito de comparação, foi utilizado como tratamento controle T4: a sucessão milho - batata em preparo convencional de solo (Milho PC), com uso de grade aradora a 0,20 m de profundidade antes do plantio. Para a análise estatística foi adotado o delineamento em blocos casualizados, com quatro tratamentos e seis repetições. As unidades experimentais foram constituídas por três linhas duplas de 10,0 m de comprimento. A linha dupla central teve 1,5 m de suas extremidades desconsideradas e os 7,0 m centrais, correspondente a 12,6 m² em área, definidos como unidade experimental útil ou unidade de observação. Foram avaliadas as características: produção de matéria seca da parte aérea das poáceas, resistência do solo à penetração, macroporosidade e densidade do solo, estande, número de hastes e sanidade da parte aérea da batateira, produtividade e danos aos tubérculos e dinâmica do crescimento. Os dados obtidos foram submetidos à análise de variância (ANOVA, p<=0,05). Posteriormente, as médias foram comparadas pelo teste de Tukey ao nível de 5% de probabilidade de erro, pelos programas estatísticos SAS e Sisvar. O preparo profundo de solo, em relação ao preparo convencional, independentemente da poácea utilizada em sucessão promoveu melhorias nos atributos físicos do solo, nos horizontes entre 0,20 e 0,60 m, propiciando redução da resistência à penetração, aumento da macroporosidade e diminuição da densidade, incrementou em 35,9% a produtividade da cv. Atlantic e proporcionou maior acúmulo de MS em todos os órgãos da planta. / Potato cropping in Brazil is marked by a constant need to migrate to new areas due to a high incidence of soil diseases, where the crop is annually planted after corn (Zea mays) and soil preparation is done by conventional tillage, using plow and harrow, a technique that when performed frequently can cause physical impediments in the soil\'s subsurface. There is limited research done on sustainable systems for potato production in Brazil, and these are characterized by lower use of chemical products, resulting in less detrimental impacts to the environment. Therefore, deep soil preparation for potato cropping succeeding grasses may be a viable alternative to producers attempting to reach and maintain high levels of production and quality of potato tubers without having to relocate to new cropping areas. The objective of the present study was to compare two types of soil preparation (i.e. conventional tillage and deep tillage) for potato crops (Solanum tuberosum) cv. Atlantic, succeeding the cultivation of a grass type, evaluating grass and soil characteristics, and productivity and growth dynamics of the potato crop. The experiment was conducted for one year starting in September 2011 in an area belonging to the Crop Science Department, ESALQ/USP , located at 22°42\'09\'\' South Latitude and 47°38\'01\'\' West Longitude at 569 m of altitude. It was studied the use of four grass types succeeded by potato cropping distributed in treatments: T1: Panicum maximum cv. Tanzania and deep tillage soil preparation (Tanzânia PP), T2: Brachiaria brizantha cv. Marandu and deep tillage soil preparation (Braquiária PP) and T3: corn \'AG 6080\', deep tillage soil preparation (Milho PP). A fourth treatment was used as control treatment, T4: corn \'AG 6080\', using conventional tillage soil preparation (Milho PC), preparing the soil at 0.20 m depth before planting the potato crop. For statistical analysis it was adopted a randomized block design with four treatments and six replications. Each experimental unit consisted of three double rows of 10.0 m in length. Plants located in the final 1.5 m ends of each row were discarded and the 7.0 m located in the center were used, which corresponded to 12.6 m² in total area. The grass characteristic evaluated was the dry matter (DM) production above ground level, the soil characteristics evaluated were: resistance to penetration, macroporosity, and density, and finally the potato characteristics studied were: bulk density, number and sanity of potato shoots, and tubers production and occurrence of damage to tubers and the growth dynamics of the potato crop. Data were subjected to analysis of variance (ANOVA p<=0.05). Tukey test was used to compare means adopting a 5% level to assess statistical significance using the softwares SAS and Sisvar. Deep soil tillage compared to conventional tillage promoted improvements in soil physical properties, for soil horizons between 0.20 and 0.60 m, providing lower resistance to penetration, increased macroporosity and lower soil density, regardless of the grass type, what resulted in increases of 35.9% in productivity of potato crop cv. Atlantic, with a greater DM accumulation in all plant organs evaluated.

Le poids et la teneur en sucres du fruit sont deux caractères complexes, importants pour la qualité de la tomate. L'objectif de cette thèse est de disséquer ces deux caractères par une démarche pluridisciplinaire, impliquant des approches écophysiologiques, génétiques et moléculaires. Une population de 20 lignées d'introgression de Solanum chmielewskii dans le fonds génétique de S. lycopersicum a été cultivée en 2006 et en 2007 sous deux conditions de charges en fruits afin de moduler sa disponibilité en carbone : une forte charge où tous les fruits sont conservés sur les bouquets, et une faible charge constituée par un unique fruit par bouquet. Des indicateurs de processus écophysiologiques impliqués dans le poids et la teneur en sucres du fruit ont été mesurés ou estimés. Ils ont permis de caractériser les principaux processus écophysiologiques sous-jacents aux QTL de qualité, notamment la division et l'expansion cellulaire, la transpiration du fruit, et l'allocation carbonée pour la synthèse de composés structuraux. Un fort effet de la charge en fruits a été mis en évidence sur l'expression des QTL pour la plupart des caractères observés, indiquant l'occurrence d'interactions génotype x charge en fruits. L'utilisation d'un modèle écophysiologique prédisant la teneur en sucres d'un fruit de tomate à maturité, combiné à une détection de QTL, a permis d'identifier des colocalisations entre QTL de qualité et QTL de variables de fonctionnement du fruit telles que la fourniture du fruit en assimilats, la transformation métabolique des sucres en d'autres composés, ou la dilution des composés par l'entrée d'eau dans le fruit. Enfin, une lignée d'introgression portant des QTL de poids frais et de sucres avec des allèles aux effets opposés ainsi que la lignée conférant le fonds génétique ont été étudiées au niveau moléculaire par une analyse du transcriptome en phase d'expansion cellulaire. Des gènes candidats dont le niveau d'expression serait associé aux variations de poids et de teneurs en sucres du fruit, engendrées par une modification de la charge en fruits ont été identifiés. L'analyse en cinétique de l'expression de quelques gènes candidats a permis de mettre en évidence des liens entre variables écophysiologiques et moléculaires.

Non-mycorrhizal fungal endophytes are able to colonize internally roots without causing visible disease symptoms establishing neutral or mutualistic associations with plants. These fungi known as non-clavicipitaceous endophytes have a broad host range of monocot and eudicot plants and are highly diverse. Some of them promote plant growth and confer increased abiotic-stress tolerance and disease resistance. According to such possible effects on host plants, it was aimed to isolate and to characterize native fungal root endophytes from tomato (Lycopersicon esculentum Mill.) and to analyze their effects on plant development, plant resistance and fruit yield and quality together with the model endophyte Piriformospora indica. Fifty one new fungal strains were isolated from desinfected tomato roots of four different crop sites in Colombia. These isolates were roughly characterized and fourteen potential endophytes were further analyzed concerning their taxonomy, their root colonization capacity and their impact on plant growth. Sequencing of the ITS region from the ribosomal RNA gene cluster and in-depth morphological characterisation revealed that they correspond to different phylogenetic groups among the phylum Ascomycota. Nine different morphotypes were described including six dark septate endophytes (DSE) that did not correspond to the Phialocephala group. Detailed confocal microscopy analysis showed various colonization patterns of the endophytes inside the roots ranging from epidermal penetration to hyphal growth through the cortex. Tomato pot experiments under glass house conditions showed that they differentially affect plant growth depending on colonization time and inoculum concentration. Three new isolates (two unknown fungal endophyte DSE48, DSE49 and one identified as Leptodontidium orchidicola) with neutral or positiv effects were selected and tested in several experiments for their influence on vegetative growth, fruit yield and quality and their ability to diminish the impact of the pathogen Verticillium dahliae on tomato plants. Although plant growth promotion by all three fungi was observed in young plants, vegetative growth parameters were not affected after 22 weeks of cultivation except a reproducible increase of root diameter by the endophyte DSE49. Additionally, L. orchidicola increased biomass and glucose content of tomato fruits, but only at an early date of harvest and at a certain level of root colonization. Concerning bioprotective effects, the endophytes DSE49 and L. orchidicola decreased significantly disease symptoms caused by the pathogen V. dahliae, but only at a low dosis of the pathogen. In order to analyze, if the model root endophytic fungus Piriformospora indica could be suitable for application in production systems, its impact on tomato was evaluated. Similarly to the new fungal isolates, significant differences for vegetative growth parameters were only observable in young plants and, but protection against V. dahliae could be seen in one experiment also at high dosage of the pathogen. As the DSE L. orchidicola, P. indica increased the number and biomass of marketable tomatoes only at the beginning of fruit setting, but this did not lead to a significant higher total yield. If the effects on growth are due to a better nutrition of the plant with mineral element was analyzed in barley in comparison to the arbuscular mycorrhizal fungus Glomus mosseae. While the mycorrhizal fungus increased nitrogen and phosphate uptake of the plant, no such effect was observed for P. indica. In summary this work shows that many different fungal endophytes can be also isolated from roots of crops and, that these isolates can have positive effects on early plant development. This does, however, not lead to an increase in total yield or in improvement of fruit quality of tomatoes under greenhouse conditions. / Endophyten, die nicht zu den Mykorrhizapilzen gehören, können das Innere von Wurzeln ohne sichtbare Krankheitssymptome besiedeln und bilden so mit der Pflanze neutrale oder mutualistische Wechselwirkungen. Diese Pilze, auch als nicht-clavicipetale Endophyten bekannt, haben ein breites Wirtsspektrum von mono- und dikotyledonen Pflanzen und weisen eine hohe Diversität auf. Einige von ihnen fördern Pflanzenwachstum und erhöhen Resistenz und Toleranz gegenüber biotischem und abiotischem Stress. Ausgehenden von diesen möglichen Effekten auf ihre Wirtspflanzen war das Ziel der vorliegenden Arbeit die Isolierung und Charakterisierung neuer pilzlicher Wurzelendophyten der Tomate (Lycopersicon esculentum Mill.) und die Analyse ihres Einflusses auf Pflanzenentwicklung und Pflanzenresistenz, sowie auf Ertrag und Fruchtqualität unter Einbeziehung des Modellendophyten Piriformospora indica. Aus vier verschiedenen Anbaugebieten in Kolumbien konnten 51 neue Pilzstämme von oberflächensterilisierten Tomatenwurzeln isoliert werden. Diese Isolate wurden vorcharakterisiert und 14 potentielle Endophyten bezüglich ihrer Taxonomie, ihrer Besiedlungsmuster und ihres Einfluss auf das Pflanzenwachstum näher untersucht. Sequenzierung der ITS Region des ribosomalen RNA Genclusters und genaue morphologische Charakterisierung zeigten, dass sie zu verschiedenen phylogenetischen Gruppen innerhalb der Ascomycota gehören. Neun Morphotypen ließen sich beschreiben, wobei sechs zu den ‚Dark Septate Endophytes’ (DSEs) gehören, aber nicht mit der bekannten Phialocephala Gruppe verwandt waren. Ausführliche konfokale mikroskopische Untersuchungen ergaben sehr verschiedene Besiedelungsmuster der Wurzelendophyten vom Endringen in die Epidermis bis zum Hyphenwachstum durch den Kortex. Topfexperimente unter Gewächshausbedingungen zeigten dass die Isolate in Abhängigkeit von der Inokulumkonzentration und der Zeit der Besiedlung das Wachstum der Tomaten sehr unterschiedlich beeinflussten. Drei neue Isolate (die beiden unbekannte pilzlichen Endophyten DSE48 und DSE49 und eines identifiziert als Leptodontidium orchidicola) mit neutralen oder positiven Effekten wurden für weitere Versuche ausgewählt. In mehreren Experimenten sollte ihr Einfluss auf das vegetative Wachstum, auf Ertrag und auf Fruchtqualität untersucht werden, sowie ihre Fähigkeit die Auswirkungen des Pathogens Verticillium dahliae auf Tomatenpflanzen zu vermindern. Obwohl wachstumsfördernde Effekte durch alle drei Pilze in jungen Pflanzen beobachtet wurden, waren vegetative Wachstumsparameter nach 22 Wochen der Besiedlung nicht mehr beeinflusst bis auf ein signifikante Erhöhung des Wurzeldurchmessers durch den Endophyten DSE49. L. orchidicola dagegen erhöhte die Biomasse und den Glukosegehalt der Früchte, aber nur zu frühen Ernteterminen und bei einer bestimmten Intensität der Wurzelbesiedelung. Hinsichtlich eines schützenden Effekts, konnten die Endophyten DSE49 und L. orchidicola die Krankheitssymptome, die durch V. dahliae verursacht wurden, vermindern, aber nur bei einem geringen Pathogendruck. Um zu überprüfen, ob der Modellendophyt P. indica in Produktionssytemen eingesetzt werden kann, wurde seine Auswirkungen auf Tomaten untersucht. Ähnlich wie die neuen pilzlichen Isolate, zeigte aber auch er seinen fördernden Einfluss nur auf das frühe vegetative Wachstum. Schützende Effekte gegen V. dahliae konnten ebenfalls nur bei niedrigem Pathogendruck konstant beobachtet werden. Wie L. orchidicola erhöhte P. indica die Biomasse an marktfähigen Tomaten am Anfang des Fruchtansatzes, was nicht zu einem insgesamt höheren Ertrag führte. Ob die beobachteten Effekte auf ein verbesserte Nährstoffversorgung der Pflanze zurückzuführen seien, wurde in Gerste im Vergleich mit dem arbuskulären Mykorrhizapilz Glomus mosseae untersucht. Während der Mykorrhizapilz sowohl Phosphat wie Stickstoffaufnehme der Pflanze erhöhte, konnte dies für P. indica nicht festgestellt werden. Zusammenfassend zeigt diese Arbeit, dass auch aus Wurzeln von Kulturpflanzen viele verschiedene pilzliche Endophyten isoliert werden können, und dass einige von diesen durchaus einen positiven Effekt auf die frühe Pflanzenentwicklung aufweisen. Zumindest für Tomate unter Gewächshausbedingungen führen diese Effekte aber nicht zu einer Erhöhung des Gesamtertrags oder einer nachhaltigen Verbesserung der Fruchtqualität.