Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-04-06T13:12:00Z No. of bitstreams: 1 melviscelestevilanculoscossa.pdf: 1078778 bytes, checksum: 97bdef4f96b42adf5a7860d727162f8f (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-04-24T03:59:51Z (GMT) No. of bitstreams: 1 melviscelestevilanculoscossa.pdf: 1078778 bytes, checksum: 97bdef4f96b42adf5a7860d727162f8f (MD5) / Made available in DSpace on 2016-04-24T03:59:51Z (GMT). No. of bitstreams: 1 melviscelestevilanculoscossa.pdf: 1078778 bytes, checksum: 97bdef4f96b42adf5a7860d727162f8f (MD5) Previous issue date: 2013-02-27 / CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico / A batata uma essencial “comida para todos”, é hoje uma das mais importantes culturas alimentares e constitui a quarta cultura mais importante do mundo, sendo também fonte de segurança alimentar. Todavia, muitas doenças causadas por vírus, bactérias e fungos afetam a cultura desta planta, resultando em perdas e diminuição da qualidade e segurança dos produtos agrícolas. O controle de doenças nas plantas baseia-se principalmente de pesticidas químicos que estão atualmente sujeitos a fortes restrições e requisitos regulamentares. Nesse sentido, vários peptídeos antimicrobianos têm sido a base para a concepção de novos análogos sintéticos e têm sido expressos em plantas transgênicas para conferir proteção a doenças. O desenvolvimento de plantas transgênicas, contendo um gene que sintetiza um peptídeo antibacteriano, tem sido uma das formas estudadas para se controlar doenças bacterianas. No presente estudo, plantas de batata (Solanum tuberosum), cultivar Asterix, foram transformadas com genes codificadores do peptídeo Pg-AMP1 de Psidium guajava, com objetivo de promover resistência a bactérias que afetam a cultura da batata, nomeadamente Pectobacterium atrosepticum e Pectobacterium carotovorum. Experimentos de transformação genética mediada por Agrobacterium permitiram a obtenção de 13 linhagens transgênicas de Solanum tuberosum Pg-AMP1, representando eventos independentes de transformação. Paralelamente aos experimentos de transformação genética, foram realizados bioensaios in vitro com o peptídeo recombinante purificado Pg-AMP1 contra as cepas bacterianas P. atrosepticum e P. carotovorum e bioensaio in vivo em folhas de plantas de tabaco (Nicotiana tabacum) transformada com o peptídeo com as mesmas cepas bacterianas. No que se refere à resistência das folhas contra o ataque das bactérias P. atrosepticum e P. carotovorum, as linhagens transformadas de tabaco Pg-AMP1 apresentaram sintomas de necrose menos severos comparativamente as não transgênicas. Do mesmo modo o peptídeo Pg-AMP1 apresentou atividade bactericida contra as cepas bacterianas P. atrosepticum e P. carotovorum. Assim sendo, estes resultados sugerem a viabilidade do peptídeo Pg-AMP1 na utilização de transformações genéticas de Solanum tuberosum visando resistência a bactérias patogênicas que afetam a cultura. / Potato, known as essential "food for all", is one of the most important food crops in nowadays. It is the fourth most important crop in the world and is also a source for food security. However, many diseases caused by viruses, bacteria and fungi affect plant cultivation, resulting in losses and decrease the quality and safety of agricultural products. The control of plant diseases is mainly based on chemical pesticides that are currently subject to severe restrictions and regulatory requirements. Accordingly, various antimicrobial peptides have being the basis for new synthetic analogs designing and have been expressed in transgenic plants to confer disease protection. The development of transgenic plants containing a gene that synthesizes an antibacterial peptide, has been has been used to bacterial diseases control. In this study, potato plants (Solanum tuberosum) Asterix, were transformed with genes encoding the peptide Pg-AMP1 from Psidium guajava aiming to produce resistant plants to Pectobacterium atrosepticum and Pectobacterium carotovorum. Experiments of genetic transformation by Agrobacterium - mediated allowed 13 different events of transgenic Solanum tuberosum Pg-AMP1, representing different transformation events. In parallel to genetic transformation experiments in vitro bioassay with recombinant peptide purified Pg-AMP1 was performed. Bacterial strains P. atrosepticum and P. carotovorum were evaluated and in vivo in Tobacco (Nicotiana tabacum) leaves from transformed plants containing the peptide. In resistance assay against P. atrosepticum and P. carotovorum in tobacco plants showed less severe symptoms compared to non-transgenic. Likewise the Pg- AMP1 peptide showed bactericidal activity against bacterial strains P. atrosepticum and P. carotovorum. Thus, these results suggest the feasibility of the peptide Pg- AMP1 the use of genetic transformation of Solanum tuberosum for resistance to pathogenic bacteria that affect the crop.

The Cretaceous–Paleogene (K/Pg) boundary marks one of the major crises in the history of life on Earth. The cause is widely regarded as a large bolide impact at Chicxulub, Mexico, coincident with a major series of volcanic eruptions on the Deccan Plateau, India. Fieldwork in the Brazos River area of Texas has involved an investigation of the sections on the Brazos River and its tributaries. A previously overlooked K/Pg section (RBS) on the Brazos River was found and contains the most accessible and complete K/Pg boundary succession in the area. The RBS succession provides a clear exposure of the various lithological units within the Paleocene and was used to correlate to the successions in the nearby creeks. The K/Pg boundary is also well-exposed and records an erosional relief of ~1 m, cut into the Maastrichtian mudstone succession, creating a mounded topography. The overlying ‘Event Bed’, containing reworked impact spherules at its base, is shown to infill troughs on this irregular surface. The same features were recorded in tributary creeks, with all previous descriptions of these locations clearly failing to recognise the various sedimentary relationships. Distinct, thin, yellow clay horizons within the uppermost Maastrichtian mudstones are present in some sections. Geochemical analysis and radiometric dating have confirmed these as volcanic ashes, with extracted zircons giving a date of 65.95+0.04 Ma. These ash bands are located in Maastrichtian mudstones just below the K/Pg boundary and the recorded date is, within error, that of the K/Pg boundary. This identification of this latest Maastrichtian volcanic ash negates the suggestion of a pre-K/Pg boundary impact, a pre-extinction impact or multiple impacts. The benthic foraminiferal data generated indicates significant changes in palaeoecology of the benthic foraminifera across the K/Pg boundary. The benthic foraminifera do not experience a mass extinction, unlike the planktic foraminifera, which were significantly affected by the end-Maastrichtian extinction event. The benthic foraminferal assemblage appears to only experience transient, short-lived changes with pulses of agglutinated, elongate and large species in the early Paleocene. Mono-specific samples of Lenticulina rotulata have been analysed for stable isotopes and the data may indicate the presence cyclicity across the K/Pg boundary interval. In the earliest Paleocene significant negative δ18O excursions near the Pα/P1a and NP1/NP2 boundary represents a potential hyperthermal event that may be coeval with the DAN-C2 and Lower C29n events respectively recorded at Gubbio, and in the Atlantic Ocean. A sequence stratigraphy package is determined based on the micropaleontology and sedimentology in the Brazos River area. The latest Maastrichtian is marked by a sealevel rise immediately before the K/Pg boundary. Immediately after the K/Pg event, sealevel fell and is recorded as a change from mid to inner shelf. The condensed unit of the Middle Sandstone Bed (MSB) represents a Transgressive systems tract, with increasing diversity and abundance of benthic foraminifera to the top of the MSB, where maximum abundance and diversity is marks a Maximum Flooding Surface. The interval above indicates sea-level continuing to rise to a mid to outer-shelf setting. These sealevel changes are also recorded at the same stratigraphic level in Alabama, and at more distal K/Pg boundary sections (e.g., Denmark and Tunisia) suggesting that these sealevel changes are eustatically controlled.

This thesis is dedicated to the proposition that ideology is a spectrum through which the work of Vladimir Nabokov has not previously been considered. It is the first unambiguous attempt at a reading which foregrounds questions of politics and ideology, and one which does not conform to the intentional narrative of the author’s self-designated political provenance. In this sense, it represents an original contribution to the field. The work of Louis Althusser, in addition to other critics under the aegis of Marxist criticism such as Pierre Macherey and Fredric Jameson, are used to interrogate issues of ideology in Nabokov’s early career; a period between 1926-1939 which coincides with the publication of his first Russian novel to the completion of his first in English.

La paroi des cellules végétales subit des modifications afin de s'assouplir ou de se rigidifier selon les besoins de la plante. Cette paroi est une structure complexe, composée de cellulose, d'hémicellulose et de pectines. Les modifications subies par les pectines au cours de l'élongation cellulaire sont encore assez peu caractérisées. Dans ce contexte, le but de ce projet est d'étudier le rôle de deux polygalacturonases (PG) dans le développement racinaire de la plante modèle A. thaliana. Les PG sont des enzymes de dégradation des homogalacturonanes (HG), le composant pectique majoritaire de la paroi primaire. Notrehypothèse est que les PG dégradent partiellement les HG des parois longitudinales des cellules racinaires en élongation. Cette dégradation engendrerait un assouplissement pariétal localisé, permettant la croissance anisotropique des cellules. Nos résultats indiquent que les gènes des deux PG étudiées, nommés PG ROOT APICAL MERISTEM (PG RAM) et PG ROOT (PG R) sontexprimés de façon complémentaire dans la racine, l'un dans le méristème racinaire (PG RAM), et l'autre dans la zone d'élongation et de différenciation (PG R). De plus, la sur-expression de la protéine PG R entraine une augmentation de l’élongation des hypocotyles étiolés, ainsi qu'une augmentation de la densité de racines latérales par rapport au sauvage, démontrant son rôle dans le développement racinaire et dans l'allongement cellulaire. Enfin, nous avons démontré que l'expression des gènes de ces PG était contrôlée de façon différentielle par les facteurs de transcription de la famille PLETHORA (PLT). / Plant cell wall structure is modified to control its stiffness or flexibility according to plant’s requirements. The cell wall is a complex structure, composed of cellulose, hemicelluloses and pectins. Pectin modifications during cellular elongation are not very well characterized. In this context, the aim of this project is to study the roles of two polygalacturonases (PG) in the root development on the model plant A. thaliana. PG are homogalacturonans (HG) degradation enzymes, HG being the major pectic component of the primary cell wall. This degradation would lead to a local parietal relaxation, allowing anisotropic growth of the cells. Our results show that the two studied PG, named PG ROOT APICAL MERISTEM (PG RAM) and PG ROOT (PG R), are expressed in complementary areas of the root, either in the root apical meristem (PG RAM) or in the elongated and differenciated root tissues (PG R). Furthermore, the over-expression of PG R results in longer etiolated hypocotyls and increases root density when compared to wild-type, demonstrating its function in root development and in cell elongation. Finally, we demonstrated that expression of these two PG genes is under the control of PLETHORA (PLT) family transcription factors, by differentially ways

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Les membranes cellulaires sont des cibles préférentielles de la dégradation induite par les espèces réactives de l’oxygène produites durant la sécheresse et par la stimulation d’activités hydrolytiques. La biosynthèse des lipides des chloroplastes peut être importante pour la tolérance à la sécheresse ainsi que pour la reprise après réhydratation. Dans ce travail nous avons étudié le métabolisme des lipides des membranes chloroplastiques, monogalactosyldiacylglycerol (MGDG), digalactosyl-diacylglycerol (DGDG), sulfoquinovosyldiacylglycerol (SQDG), phosphatidyl-glycerol (PG), dans le cadre de la sécheresse et de la reprise après la fin de la contrainte hydrique. Dans ce but, nous avons mesuré la teneur des lipides des feuilles, suivi l’incorporation du précurseur 14C-acétate dans les lipides et analysé l’expression des gènes codant les enzymes de biosynthèse des lipides (MGD1, MGD2, DGD1, DGD2, SQD2 et PGP1) durant le stress hydrique et après réhydratation. Afin de mieux comprendre le rapport entre le métabolisme de ces lipides et la tolérance à la sécheresse, nous avons travaillé sur deux cultivars de Vigna unguiculata L. Walp, un tolérant (cv. EPACE) et l’autre sensible (cv. 1183) à la sécheresse. Les séquences complètes des ADNc des gènes VuMGD1, VuMGD2, VuDGD1, VuDGD2, VuSQD2 et VuPGP1 ont été obtenues par le criblage d’une banque d’ADNc de V.unguiculata. Les résultats montrent qu’en condition de stress hydrique le cultivar tolérant, en plus de préserver la teneur en lipides, est capable de stimuler la biosynthèse du DGDG augmentant significativement le rapport DGDG:MGDG de ces membranes. Nous suggérons que le DGDG accumulé en sécheresse est exporté vers les membranes extrachloroplastiques et que cela contribue à la tolérance à la contrainte hydrique. Les effets de la perte d’eau cellulaire sur les membranes ont des conséquences directes sur la capacité des plantes à reprendre après réhydratation. 48 heures après réarrosage, le cv. sensible 1183 n’est pas capable de récupérer en termes de teneurs en galactolipides et incorporation de précurseur. Chez le cv. tolérant, par contre, la teneur en DGDG demeure élevé, même après réhydratation. En conclusion, nos résultats suggèrent l’importance des lipides membranaires dans la tolérance/sensibilité des plantes au déficit hydrique, en particulier la balance entre des classes lipidiques de propriétés physico-chimiques différentes (SQDG versus PG et DGDG versus MGDG) qui pourraient affecter la structure et le fonctionnement des membranes / Membranes are main targets of degradation by reactive oxygen species and hydrolytic activities induced by drought. Chloroplasts lipid biosynthesis, especially galactolipids monogalactosyl-diacylglycerol (MGDG) and digalactosyl-diacylglycerol (DGDG) are important for plant tolerance to water deficit and for recovery after rehydration. In this thesis, we studied the metabolism of the chloroplast membrane lipids, MGDG, DGDG, sulphoquinovosyl-diacylglycerol (SQDG), phosphatidyl-glycerol (PG) under drought and during recovery from drought. Aiming this, we measured leaf lipids content, followed 14Cacétate incorporation and expression of genes coding for chloroplast membrane lipid synthases (MGD1, MGD2, DGD1, DGD2, SQD2 and PGP1) during drought and recovery. In order to better understand the relationship between drought tolerance and lipid metabolism, two cultivars of Vigna unguiculata L. Walp, one drought tolerant (cv. EPACE) the other drought susceptible (cv. 1183) were compared. The cDNA complete sequences for VuMGD1, VuMGD2, VuDGD1, VuDGD2, VuSQD2 and VuPGP1 were obtained from screening of a V.unguiculata cDNA library. The results showed that under water stress conditions, the tolerant cultivar, besides its ability to preserve its lipids pool despites drought, is able to strongly stimulate the DGDG biosynthesis, increasing the DGDG:MGDG ratio in its membranes. We suggest that DGDG accumulated under drought condition, when phosphate is deficient, is exported for extrachloroplastic membranes, and thus contributes to plant drought tolerance. Effects of loss of water on cell membranes have direct consequences on plant capacity to recover from stress. 48 hours after rewatering, the susceptible cv. 1183 was not able to fully recover from a moderate stress in terms of leaf galactolipid content and acetate incorporation into MGDG. In EPACE-1, MGDG leaf content remained unchanged after rehydration and DGDG remained higher than in the control plants. In conclusion, our results highlight the importance of membrane lipids in plant adaptation to water deficit and in their capacity to recover from stress. Of particular importance is the balance between lipid classes with various physico-chemical properties (SQDG versus PG, DGDG versus MGDG), since they most likely have a profound influence on membrane structure and function

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2016-10-20T19:09:28Z No. of bitstreams: 1 2016 - Carlos Magno Moreira de Oliveira.pdf: 3071191 bytes, checksum: 379c33cebd9108d71d2092ecebb6104d (MD5) / Made available in DSpace on 2016-10-20T19:09:28Z (GMT). No. of bitstreams: 1 2016 - Carlos Magno Moreira de Oliveira.pdf: 3071191 bytes, checksum: 379c33cebd9108d71d2092ecebb6104d (MD5) Previous issue date: 2016-02-26 / CAPES / Commercial plantations of Eucalyptus has increased in Brazil, mainly in the state of Minas Gerais. The assessment of the effects of soil and climatic variables on the growth of trees becomes important tool to optimize management activities. In this perspective, this study aims to adjust and parameterize the 3-PG model for the North of Minas Gerais, using data from permanent plots of forest inventory, climate data from weather stations and data from remote sensing. This study was conducted in Eucalyptus of commercial plantations in the city of Bocaiuva (Minas Gerais). To parameterize the constant parameters of the relationship between DAP and height (H) relationship of power between DAP and height (NHB), constant relationship between volume and DAP (aV) and relationship of power between volume and DAP (NVB) were used in 2031 comments. The PG-3 model was run with parameters suggested in literature for the region and then executed with changes in the parameters mentioned above. To evaluate the effect of climate variability on planting were assessed estimates of 3-PG model fed with climatological normal and monthly averages and then analyzed the effects of environmental modulators fans and fDPV on the growth of planting. The database of climatological normals were obtained from INMET and global solar radiation was obtained from the GL 1.2 model for South America. The database with monthly average was acquired by INMET, and the precipitation was obtained from tropical TRMM satellite and solar radiation was estimated by the model proposed by FAO 56. Subsequently, we evaluated the efficiency of the 3-PG model in estimating the growth and production of settlement regarding estimates of empirical models, considering the FR parameter (Fertility Rating) as a site quality indicator. Through significant improvement was observed statistical analysis of procedural modeling with the modification of the suggested parameters, indicating that the values of this parameter can be used for other municipalities that region. Statistical analyzes showed that there was a reduction of variation of the data through the standard error of estimate (Syx%) and model efficiency (EF) greater than 0.80 for DBH, height and volume, indicating significant improvement in the model estimates . Comparing the estimates of dendrometric variables with climatological normal and monthly averages, it is observed, the graphics, the estimates were similar, with the monthly averages showed higher estimates. Statistical analysis demonstrated that the monthly averages were closer to those observed data, Syx 28% and EF 0.82 to volume while normal climatic Syx% showed almost 60% and EF 0.22. fAS modulator showed greater restriction on the development of trees, especially in the months of July, August and September. The procedural modeling showed average yield estimates in respect of empirical modeling, and the site estimated by 3-PG showed values close to the average estimated by site traditional model. The FR parameter on soil fertility, showed good relationship with the classification of production sites, and further studies to improve the accuracy in the classification of sites indexes. The 3-PG model can make accurate estimates of dendrometric variables, showing an important tool for evaluating areas with fitness for forest production, considering the effect of environmental and climate variables in the growth of trees. The procedural modeling can be used together with empirical tools to assess the growth and production of forest plantations on different management activities and in the future producing areas. / Plantios comerciais de Eucalyptus tem aumentado no Brasil, principalmente no estado de Minas Gerais. A avalia??o dos efeitos das vari?veis ed?ficas e clim?ticas sobre o crescimento das ?rvores torna-se ferramenta importante para otimizar as atividades de manejo. Nessa perspectiva, esse trabalho tem por objetivo ajustar e parametrizar o modelo 3-PG para regi?o Norte de Minas Gerais, utilizando dados de parcelas permanentes de invent?rio florestal, dados clim?ticos de esta??es climatol?gicas e dados oriundos de sensoriamento remoto. Esse estudo foi realizado em plantios comerciais do g?nero Eucalyptus no munic?pio de Bocai?va (MG). Para parametrizar os par?metros constante de rela??o entre DAP e altura (aH), pot?ncia de relacionamento entre DAP e altura (nHB), constante de relacionamento entre volume e DAP (aV) e pot?ncia de relacionamento entre volume e DAP (nVB) foram utilizados 2031 observa??es. O modelo 3-PG foi executado com par?metros sugeridos na bibliografia para regi?o e posteriormente executada com modifica??es nos par?metros mencionados anteriormente. Para avaliar o efeito da variabilidade clim?tica sobre o plantio, foram avaliadas as estimativas do modelo 3-PG alimentado com normais climatol?gicas e m?dias mensais e posteriormente analisado os efeitos dos moduladores ambientais fAS e fDPV sobre o crescimento do plantio. O banco de dados das normais climatol?gicas foram obtidas do INMET e a radia??o solar global foi obtido do modelo GL 1.2 para am?rica do sul. O banco de dados com m?dias mensais foi adquirido pelo INMET, sendo que a precipita??o foi obtida do sat?lite tropical TRMM e a radia??o solar global foi estimado pelo modelo proposto pela FAO 56. Posteriormente, foi avaliado a efici?ncia do modelo 3-PG em estimar o crescimento e produ??o do povoamento em rela??o as estimativas dos modelos emp?ricos, considerando o par?metro FR (Fertility Rating) como indicador da qualidade de s?tio. Por meio de an?lises estat?sticas foi observado melhora significativa da modelagem processual com a modifica??o dos par?metros sugeridos, indicando que os valores dessa parametriza??o podem ser utilizados para outros munic?pios dessa regi?o. As an?lises estat?sticas demonstram que houve redu??o da varia??o dos dados por meio do erro padr?o da estimativa (Syx%) e efici?ncia do modelo (EF) maior que 0,80 para as vari?veis DAP, Altura e Volume, indicando melhoria significativa nas estimativas do modelo. Comparando-se as estimavas das vari?veis dendrom?tricas com normais climatol?gicas e medias mensais, observa-se, pelos gr?ficos, que as estimativas foram semelhantes, sendo que as medias mensais apresentaram estimativas superiores. A an?lise estat?stica demonstra que as medias mensais foram mais pr?ximas aos dados observados, com Syx% 28 e EF de 0,82 para volume, enquanto que as normais climatol?gicas apresentaram Syx% de quase 60% e EF de 0,22. O modulador fAS apresentou maior restri??o no desenvolvimento das ?rvores, principalmente nos meses de julho, agosto e setembro. A modelagem processual apresentou estimativas de produ??o m?dia em rela??o a modelagem emp?rica, sendo que o s?tio estimado pelo 3-PG apresentou valores pr?ximos ao s?tio m?dio estimado pela modelam tradicional. O par?metro FR, relativo a fertilidade do solo, apresentou boa rela??o com a classifica??o de s?tios de produ??o, sendo necess?rios outros estudos para melhorar a acur?cia na classifica??o dos ?ndices de s?tios. O modelo 3-PG pode realizar estimativas precisas de vari?veis dendrom?tricas, mostrando-se ferramenta importante para avalia??o de ?reas com aptid?o para produ??o florestal, por considerar o efeito de vari?veis ambientais e clim?ticas no crescimento das ?rvores. A modelagem processual pode ser utilizada juntamente com ferramentas emp?ricas para avaliar o crescimento e produ??o de plantios florestais sobre diferentes atividades de manejo e tamb?m em ?reas futuramente produtoras.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-06-29T11:33:08Z No. of bitstreams: 1 nataliadosanjospinto.pdf: 1701558 bytes, checksum: a1c89a03566132430636ade1b70b0e04 (MD5) / Approved for entry into archive by Diamantino Mayra (mayra.diamantino@ufjf.edu.br) on 2016-07-05T14:36:36Z (GMT) No. of bitstreams: 1 nataliadosanjospinto.pdf: 1701558 bytes, checksum: a1c89a03566132430636ade1b70b0e04 (MD5) / Made available in DSpace on 2016-07-05T14:36:36Z (GMT). No. of bitstreams: 1 nataliadosanjospinto.pdf: 1701558 bytes, checksum: a1c89a03566132430636ade1b70b0e04 (MD5) Previous issue date: 2012-08-31 / O morango é produzido e consumido nas mais variadas regiões do mundo, sendo a espécie do grupo de pequenos frutos de maior apreciação e grande retorno econômico. Um dos principais problemas na cultura do morangueiro é a incidência de doenças, que podem aparecer em várias fases do ciclo da cultura, atacando desde as mudas recém plantadas até os frutos na fase final de produção. Devido a susceptibilidade às doenças e pragas, o uso de pesticidas é usual no cultivo de morangos. Nesse sentido, o uso de variedades resistentes a fungos e bactérias pode ser uma importante alternativa visando a melhoria da qualidade dos frutos e um menor custo de produção dos mesmos, uma vez que os consumidores exigem cada vez mais, frutos com menor nível residual de agrotóxicos. No presente estudo, plantas de Nicotiana tabacum foram transformadas com os genes OxDc de Flammulina velutipes e Pg-AMP1 de Psidium guajava com o objetivo de avaliar os efeitos da enzima Oxalato Descarboxilase, produzida pelo gene OxDc, na resistência das plantas a fatores que induzem a morte celular de tecidos infectados pelo fungo Fusarium oxysporum, assim como os efeitos in vitro do extrato bruto contendo o peptídeo Pg-AMP1 extraído das folhas de tabaco contra a bactéria Gram-negativa Xanthomonas fragarie. Experimentos de transformação genética mediada por Agrobacterium permitiram a obtenção de 8 linhagens transgênicas de N. tabacum OxDc e 7 linhagens transgênicas de N. tabacum Pg-AMP1, representando eventos de transformação distintos. As plantas foram caracterizadas molecular e bioquimicamente a fim de se confirmar a inserção, expressão e funcionalidade dos genes inseridos nas linhagens obtidas tanto para o gene OxDc quanto para o Pg-AMP1. Os testes de resistência ao ácido oxálico mostraram danos menos severos nas linhagens transformadas de X tabaco OxDc do que nas plantas não transformadas. No que se refere à resistência das folhas ao ataque pelo fungo Fusarium Oxysporum, o gene OxDc também se mostrou capaz de conferir resistência às linhagens transgênicas. Através da técnica de Western blot, foi possível detectar a presença do peptídeo Pg-AMP1 no extrato bruto extraído das folhas transformadas de tabaco Pg-AMP1. O bioensaio realizado in vitro utilizando-se o extrato bruto contendo o peptídeo Pg-AMP1 demonstrou a ação bactericida desse peptídeo contra a bactéria fitopatogênica Xanthomonas Fragarie. Em conjunto os resultados indicam a viabilidade da utilização dos genes OxDc e Pg-AMP1 transformação genética de morangueiro visando à redução nos danos causados por fitopatógenos que acometem suas lavouras, assim como a redução no uso de pesticidas. / The strawberry is produced and consumed in a variety of regions in the world, being the group of small fruits’ species of greater appreciation and high economic returns. A major problem in strawberry culture is the disease incidence that can appear in several stages of the cycle, attacking from the newly planted seeding to the fruit in the final stage of production. Due to this susceptibility to diseases and pests, the pesticide use is common in strawberries cultivation. Regarding this, the use of varieties resistant to fungi and bacteria may be a good alternative in order to improve fruit quality and to lower production cost, since consumers are increasingly demanding fruits with a lower level of pesticides. In the present study, Nicotiana tabacum plants were transformed with Flammulina velutipes OxDc gene and Psidium guajava Pg-AMP1 aiming to evaluate the effect of the enzyme Oxalate Decarboxylase produced by the gene OxDc in plant resistance to factors that induce cell death in tissues infected by the fungus Fusarium oxysporum, and the effect of raw extract containing the Pg-AMP1 peptide extracted from tobacco leaves against gram-negative bacterium Xanthomonas fragarie in vitro. Genetic transformation Agrobacterium-mediated experiments allowed the production of 8 transgenic lines N. tabacum OxDc and 7 transgenic lines of N. tabacum Pg-AMP1, representing different transformation events. The plants were biochemically and molecular characterized to confirm the integration, expression and function of the genes inserted in the lines obtained both for the gene OxDc and Pg-AMP1. Tests for resistance to 20 mM oxalic acid had less severe symptoms in OxDc transformed tobacco lines than the non-transformed plants. Concerning the strength of the leaves against Fusarium oxysporum attack, OxDc gene has also shown to confer resistance to the transgenic lines. It was possible to detect the presence of Pg-AMP1 peptide in the raw extract from Pg-AMP1 tobacco leaves through Western blot. Thus, the in vitro bioassay carried out using the raw extract containing the Pg-AMP1 peptide showed bactericidal activity against the phyto-pathogenic bacteria Xanthomonas Fragarie. Together these results XII determine the viability of OxDc and Pg-AMP1 genes in the use of strawberry genetic transformation aiming the reduction in the damage caused by pathogens that attack the crop.

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Made available in DSpace on 2015-03-26T13:53:06Z (GMT). No. of bitstreams: 1 texto completo.pdf: 631158 bytes, checksum: 02116694fb47515646edb72c63edbe00 (MD5) Previous issue date: 2009-02-16 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / An alternative to quantify and predict the forest potential productivity is the use of process-based models (PBMs). Among the various existent models in the forest area, the 3- PG (Physiological Principles in Prediction Growth) has been used more recently, which, in essence, is a model of water and solar radiation use efficiency and of carbon partitioning. In Brazil, the results obtained with this model have been good, but these results also show the need of parameterisation and calibration of the model through the adjustment of the values of the parameters and relationships, for the conditions of forest sites. There are not works of this type for the cerrado of Minas Gerais (MG). In this study, we made a parameterisation, calibration and validation of the 3- PG model for fast-growing eucalypt plantations at the cerrado of Minas Gerais. The study was conducted with data from the regions of Curvelo and Itacambira MG and two genetic materials (hybrid clones of E. grandis x E. urophylla) were evaluated during a cycle of production (0,25, 1, 2, 3, 5 and 7 years). At the stage of parameterisation, plots constituted of 40 plants were established. The diameter of the plants was measured at 1,30 m high (dbh), and four plants with dbh of around the average per plot were sampled destructively. The diameter (dbh), the total (H) and commercial (Hc) height, the stand volume excluding branch & bark (V) and the aboveground and root biomass were measured in these trees. It was also determined the specific leaf area (σf), the wood density (ρ) and the fraction of stem biomass as branch and bark (pBB). The litterfall rate has been monitored through collectors of 0.5 x 0.5 m distributed in six random points in each plot. Through non-linear models allometric relationships were adjusted, that describe the relationship among the total height, the stem biomass including branches and bark, and the stand volume as a function of dbh, and also equations that describe the behavior of the σf, ρ and pBB as a function of the age. During the stage of calibration, the estimates for dbh, H, V, dry matter of stem and basal area, obtained through the parameterised model, were compared to data measured in the field in each situation and the eventual deviations were minimized by adjusting the values of some variables of the model that were not measured. At the stage of validation, estimates for dbh, V and H, obtained through the parameterized and calibrated model, were compared to independent data (continuum and pre-cut forest inventory) to evaluate the reliability and capacity of extrapolation of the model. In relation to the dendrometric data, the material 3334 has a much more superior productivity than the material 3336 in the region of Curvelo, but in Itacambira the behavior of both materials in terms of productivity is similar. As concerning the performance of the model, it was satisfactory when simulating the growth of eucalypt forests for the clones 3334 and 3336 in Itacambira, and for the clone 3336 in the region of Curvelo. The estimates obtained through the general model developed for the region of cerrado also present significant correlation with the observed data, either at the stage of calibration or at the stage of validation. For the material 3334 in Curvelo, even after alterations in important variables of the model it was not possible to obtain a satisfactory adjustment of the 3-PG, however, the performance of the adjusted model for this condition was superior to the other available parameterisations. In conclusion, the 3-PG model adjusted for the cerrado of Minas Gerais was efficient in simulate the growth of eucalypt forests in the region, and the performance of the model was superior to other parameterisations of available models. / Uma alternativa para a quantificação e prognose do potencial produtivo de florestas plantadas é o emprego de modelos baseados em processos. Dentre os vários modelos existentes na área florestal, mais recentemente tem-se utilizado o 3-PG (Physiological Principles in Prediction Growth), que, em essência, é um modelo de eficiência de uso de radiação solar e água, e de partição de carbono. Os resultados obtidos com este modelo no Brasil tem sido bons, mas mostram a necessidade de parametrização e calibração do mesmo, por meio de ajustes dos valores dos parâmetros e relacionamentos, para as condições do sitio florestal, não havendo trabalhos desse tipo para o cerrado de Minas Gerais (MG). Neste trabalho, realizou-se a parametrização, calibração e validação do modelo 3-PG para plantios de eucalipto na região do cerrado de MG. Para tanto, o trabalho foi conduzido com dados das regiões de Curvelo e Itacambira MG, para dois materiais genéticos (híbridos clonais de E. grandis x E. urophylla), avaliados ao longo de um ciclo produtivo (0,25, 1, 2, 3, 5 e 7 anos). Na etapa de parametrização foram estabelecidas parcelas constituídas por 40 plantas, nas quais foi medido o diâmetro a 1,30 m de altura (dap), sendo abatidas quatro plantas com dap em torno da média por parcela. O diâmetro (dap), a altura total (H) e comercial (Hc), o volume de lenho (V) e a biomassa da parte aérea e raiz foram mensuradas nestas árvores. Foram determinadas também a área foliar específica (σf), a densidade da madeira (ρ) e a fração de galho e casca em relação à biomassa da parte aérea (pBB) excluindo as folhas. A taxa de queda de litter tem sido monitorada por meio de coletores de 0,5 x 0,5 m espalhados em 6 pontos aleatórios em cada parcela. Por meio de modelos não-lineares foram ajustadas equações alométricas que descrevem o relacionamento entre a altura total, a biomassa de stem (lenho + casca + galhos) e o volume de lenho em função do dap, e também equações que descrevem o comportamento da σf, ρ e pBB em função da idade. Durante a etapa de calibração, as estimativas para dap, H, V, matéria seca de stem e área basal, obtidas pelo modelo parametrizado, foram comparadas com dados medidos no campo em cada situação e os eventuais desvios foram minimizados por meio de ajustes ( tuning ) nos valores de algumas variáveis do modelo que não foram medidas. Na etapa de validação, estimativas para dap, V e H, obtidas pelo modelo parametrizado e calibrado, foram comparadas com dados independentes (inventário florestal contínuo e précorte) para avaliar a confiabilidade e a capacidade de extrapolação do modelo. Com relação aos dados dendrométricos, o material 3334 tem produtividade muito superior ao 3336 na região de Curvelo, mas em Itacambira o comportamento dos dois materiais em termos produtivos é semelhante. Já quanto ao desempenho do modelo, o mesmo foi satisfatório, ao simular o crescimento de florestas de eucalipto para os clones 3334 e 3336 em Itacambira e para o clone 3336 na região de Curvelo. As estimativas obtidas pelo modelo geral desenvolvido para a região do cerrado também apresentaram correlação significativa, com os dados observados, tanto na etapa de calibração, quanto na de validação. Para o material 3334 em Curvelo, mesmo após alterações em variáveis importantes do modelo, não foi possível obter ajuste do 3-PG que fosse satisfatório, sendo, no entanto, o desempenho do modelo ajustado para essa condição, superior ao de outras parametrizações disponíveis. Dessa forma, conclui-se que o modelo 3-PG ajustado para o Cerrado de Minas Gerais foi eficiente em simular o crescimento de florestas de eucalipto na região, sendo o desempenho do mesmo, superior ao de outras parametrizações do modelo disponíveis.