Face à la rapidité des changements climatiques, les arbres doivent faire preuve de plasticité phénotypique. Les mécanismes épigénétiques font partie des pistes de recherche actuelles pour expliquer la plasticité phénotypique. Cette thèse visait à évaluer le rôle de la méthylation de l’ADN dans la plasticité phénotypique d’un organisme pérenne séquencé, le peuplier, en réponse à des variations de disponibilité en eau du sol. Les travaux, combinant écophysiologie et épigénomique, se sont focalisés sur le méristème apical caulinaire, centre de la morphogenèse de la tige feuillée. Trois résultats majeurs sont issus de cette thèse : i) Chaque état hydrique est associé à un méthylome et un transcriptome spécifiques, ii) Certaines régions différentiellement méthylées sont conservées dans le temps et entre contextes environnementaux, iii) Des lignées RNAi hypométhylées soumises à différents contextes hydriques présentent une réponse modifiée. Les résultats acquis lors de cette thèse appuient une contribution de la méthylation de l’ADN à la plasticité phénotypique et suggèrent un rôle des mécanismes épigénétiques dans la mémoire d’un stress chez les arbres. / Due to rapid climate changes, trees must exhibit phenotypic plasticity. Epigenetic mechanisms are part of current research to explain phenotypic plasticity. This thesis aimed to evaluate the role of DNA methylation in phenotypic plasticity of a perennial sequenced organism, poplar, in response to variations in soil water availability. The work, combining ecophysiology and epigenomics, focused on the shoot apical meristem, the center of morphogenesis of the leafy stem. Three major results emerge from this thesis: (i) Each hydric state is associated with a specific methylome and transcriptome, (ii) Some differentially methylated regions are conserved in time and between environmental contexts, (iii) Hypomethylated RNAi lines subjected to different contexts show a modified response. The results obtained during this thesis support a contribution of DNA methylation to phenotypic plasticity and suggest a role of epigenetic mechanisms in stress memory in trees.

Adaptation to environmental changes is important for the survival of living organisms. Under extreme abiotic conditions, organic molecules (such as lipids, proteins and nucleic acids) are prone to damage. Under these conditions stress response mechanisms are activated, either to prevent the source of damage or to promote the rapid turnover of damaged molecules. Like all photoautotrophic organisms, cyanobacteria are sensitive to high light intensity and oxidative stress, which induces damage to the photosynthetic apparatus. My thesis is divided in two subjects related to particular stress responses in the cyanobacterium Synechocystis sp. PCC 6803: 1) the role of Deg/HtrA proteases and 2) investigations on the small CAB-like proteins. Deg/HtrA proteases are ATP-independent serine endopeptidases with a characteristic C-terminal PDZ domain. These proteases are largely dispersed among living organisms, with many different functions, mostly involved in protein quality control. The genome of Synechocystis sp. PCC 6803 contains three genes coding for Deg/HtrA proteases: HtrA, HhoA and HhoB. These proteases are essential for survival under high light and heat stress, and may overlap in their functions. During my Ph.D. studies I focused on the identification of the precise localization of the Deg/HtrA proteases in the cyanobacterial cell, analyzed the biochemical properties of recombinant Synechocystis Deg/HtrA proteases in vitro and adopted proteomic and metabolomic approaches to study the physiological importance of these proteases. My data show that Deg/HtrA proteases are not only important in stress response mechanisms under adverse conditions, but are also involved in the stabilization of important physiological processes, such as polysaccharides biosynthesis and peptidoglycan turnover. The small CAB-like proteins (SCPs) belong to the light harvesting-like family of stress induced proteins and are thought to be involved in the photoprotection of the photosynthetic apparatus. Five small CAB-like proteins where identified in Synechocystis sp. PCC 6803 (ScpA-E). In my studies I identified another relative to the SCPs, LilA, which I found to be co-transcribed with ScpD. I also focused on the subcellular localization and identification of potential interaction partners of the SCPs.

No description available.

Submitted by Ricardo Cedraz Duque Moliterno (ricardo.moliterno@uefs.br) on 2016-04-06T23:39:59Z No. of bitstreams: 1 Disserta??o Alirio- RGV.pdf: 1134374 bytes, checksum: c5cada877e2f1b7066d7296503b7a9a8 (MD5) / Made available in DSpace on 2016-04-06T23:39:59Z (GMT). No. of bitstreams: 1 Disserta??o Alirio- RGV.pdf: 1134374 bytes, checksum: c5cada877e2f1b7066d7296503b7a9a8 (MD5) Previous issue date: 2016-02-22 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / The aims of this study were to evaluate the adaptability and stability of 14 yellow passion fruit plant hybrids and to estimate the genetic components of variance and average via mixed models (REML/BLUP), estimate the phenotypic, genotypic and environmental correlations between passion fruit characteristics in three environments. The selection of genotypes was based on methods of adaptability, as produced by the harmonic mean of genetic values (MHVG); of stability, as produced by the relative performance of genetic values (PRVG); and on a joint selection for both adaptability and stability, as produced by the harmonic mean of the relative performance of the genetic values (MHPRVG). The genetic correlations were estimated (rG), phenotypic (rF) and environment (rE) for each environment. The following traits were evaluated: fruit number (FN); total cumulative productivity (TCP); fruit mass (FM); fruit length (FL); fruit diameter (FD); peel mass (PM); peel thickness (PT); pulp mass (PUM); juice yield (JY); soluble solids (SS); titratable acidity (TA); and SS/TA (RATIO). The estimates for heritability and the genetic gains in the evaluated environments were found to have good perspectives for the selection of superior genotypes, except for traits TCP, SS, and JY. There was a marked effect from the genotype x environment interaction (GxE) for most traits, except for FL, JY, SS, TA, and SS/TA. The most stable and adaptable hybrids in the evaluated environments were BRS Gigante Amarelo (BRS Yellow Giant), HFOP-09, H09-09, GP09-02, GP09-03, and BRS Sol do Cerrado (BRS Sun of Cerrado). In 88.88% of cases the estimates of genotypic correlations were higher than phenotypic in the three environments. In Len??is genotypic correlations between FN x FM, FD, PT, PM, PUM, SS and TA, differed from the other environments. In Dom Basil?o and Rio de Contas to TCP correlated positively with FM, FL, FD and PM. In all environments the selection of fruits with higher FM facilitating higher LF, FD, PM and PUM and the selection of the oval thinner peel fruit shape. In general, for correlations between traits of agronomic importance, such as FN x TCP, SS; FM x FD, PM, PUM, RATIO; FD x FM, PUM, RATIO; FL/FD x PT e FM x RATIO showed the same behavior in the three evaluation environments, except for characteristics FN x FM, FD, PT, PM, PUM e TA in Lenc?is. / Os objetivos deste trabalho foram avaliar a adaptabilidade e estabilidade de 14 h?bridos de maracujazeiro-amarelo, estimar os componentes gen?ticos de vari?ncia e de m?dia via modelos mistos (REML/BLUP), estabelecer as correla??es fenot?picas, genot?picas e ambientais entre caracter?sticas do fruto de maracujazeiro em tr?s ambientes. Foram avaliados 14 gen?tipos de maracujazeiro nos ambientes de Dom Bas?lio-BA, Rio de Contas-BA e Len??is-BA, utilizando o delineamento experimental em blocos casualizados completos, com tr?s repeti??es e nove plantas por parcela. A sele??o gen?tipos baseou-se nos m?todos da adaptabilidade dada pela m?dia harm?nica dos valores gen?ticos (MHVG), estabilidade pela performance relativa dos valores gen?ticos (PRVG) e sele??o conjunta para adaptabilidade e estabilidade dada pela m?dia harm?nica da performance relativa dos valores gen?ticos (MHPRVG). Foram estimadas as correla??o genot?pica (rG), fenot?pica (rF) e de ambiente (rE) para cada ambiente. Foram avaliados os caracteres, n?mero de frutos (NF); produtividade total acumulada (PR); massa do fruto (MF); comprimento de frutos (CF); di?metro do fruto (DF); rela??o CF/DF; massa da casca (MC); espessura de casca (EC); massa da polpa (MP); rendimento de suco (RE); s?lidos sol?veis (SS); acidez titul?vel (AT) e RATIO (SS/AT). As estimativas de herdabilidade e os ganhos gen?ticos nos ambientes avaliados apresentaram boas perspectivas para sele??o de gen?tipos superiores. Houve efeito pronunciado da intera??o GxE para a maioria dos caracteres, exceto CF, RE, SS, AT e SS/AT. De acordo com o crit?rio MHPRVG os h?bridos mais est?veis e adapt?veis nos ambientes de avalia??o foram o BRS Gigante Amarelo, HFOP-09, H09-09, GP09-02, GP09-03 e BRS Sol do Cerrado. Em 88,88% dos casos as estimativas das correla??es genot?picas foram maiores do que as fenot?picas nos tr?s ambientes. Em len??is as correla??es genot?picas foram negativas entre NF x MF, DF, EC, MC, MP, SS e AT, divergindo dos demais ambientes. Nos ambientes de Dom Bas?lio e Rio de Contas a PR correlacionou se positivamente com MF, CF, DF e MC. Em todos os ambientes a sele??o de frutos com maiores MF proporcionar? maiores CF, DF, PC e PP e pela sele??o do formato de frutos ovais menor espessura de casca. De modo geral, para as correla??es entre caracter?sticas de import?ncia agron?mica, como NF x PR, SS; MF x DF, MC, MP, RATIO; DF x MC, MP, RATIO; CF/DF x EC e MC x RATIO apresentaram o mesmo comportamento nos tr?s ambientes de avalia??o, exceto para caracter?sticas NF x MF, DF, EC, MC, MP e AT em Len??is.

Development Finance Institutions (DFIs) have played a crucial role in moving socially responsibility considerations up on the private equity industry’s agenda. DFIs add a development impact criterion to traditional financial performance goals in the investment industry and play a catalytic role by mobilizing other investors. The gap in research regarding DFIs implications and significance in the investment community from a SRI perspective is evident. The development impact objective introduced by the DFIs is examined to understand its effects on fund managers’ decision-making and if it exists a trade-off between this objective and financial performance. An understanding of how DFIs control fund managers to act in accordance to their objective as well as how they determine compensation schemes to incentivize them to pursue high return on investments, is discussed in relation to the agency theory. Furthermore, stakeholder/shareholder consideration is examined in relation to the subject. The aim of this study is to examine how the behavior of fund managers is affected by the involvement of a DFI investor and try to add to the understanding of their significance as institutional investors in developing markets. Previous studies have been more focused on determining the financial performance of socially responsible investments by using very similar quantitative data collection methods. This thesis undertakes an in-depth approach with the purpose to understand the fund manager’s drives as well as how a DFI involvement affects the behavior and decision-making process.   This thesis undertook a qualitative research strategy and semi-structured interviews were used as the tool to understand the fund managers’ personals beliefs and perceptions of how the relationship with DFIs affect them. The selection criteria for the fund managers was that they needed to work in a fund in which a DFIs has invested. We also included DFI investors in order to understand their point of view. The interview was recorded, transcribed and later divided into themes in accordance with the thematic approach, following six steps. Our findings show that Development Finance Institutions plays an important role in emerging markets and affect fund manager behavior to a certain extent. They did not perceive a trade-off between financial performance goals and development impact objectives. We conclude that DFIs increase fund manager focus on ESG/SEE elements in the investment process. DFIs requirements and reporting obligations is used as a tool to ensure that the fund manager act in accordance to DFI objective. The fund managers were neither willing to sacrifice commercial return in favor of development impact. Lastly, the interest among the DFIs and commercial investors is fairly similar, hence reducing the conflict of interest between investors.