Historically studies have focused on either the terrestrial or aquatic environments independently. However, these systems are inherently linked through numerous pathways including organisms with complex life cycles. Both abiotic factors and predators of these organisms can influence connections by changing the number of prey moving across habitat boundaries and by changing the phenotype of prey. When the focal organisms are primary consumers, these effects may have important implications for ecosystem processes. My study investigated how terrestrial predators and abiotic factors affect the number and phenotype of herbivorous tadpole inputs into a tropical forest pond. I found that predators and abiotic factors altered survival and timing of hatching and these effects varied temporally. Thus, temporal changes in the relative importance of these threats from abiotic sources and terrestrial predators on prey with complex life cycles may potentially have implications for connections with and food web dynamics in adjacent ecosystems.

Polyploidization is a key mechanism of rapid speciation, with many phenotypic consequences which extent, however, is poorly understood. A deeper understanding of the evolutionary implications of genome duplication is limited due to lack of knowledge of the links between changes in genome, the phenotype of the individual and environmental constraints. Natural lineages closely related to model species represent the ideal systems for addressing such questions. The thesis is thus focuses on highly promising yet overlooked di-polyploid system within Arabidopsis genus. In the western Carpathians morphologically distinct populations of diploid and tetraploid plants of Arabidopsis arenosa grow along a marked altitudinal gradient. Using high-throughput DNA sequencing, measuring morphological characteristics and collecting ecological data of high alpine and foothill populations I try to reveal main trends of genetic and morphological variability of these populations. Additionaly, using morphometrics of natural and experimentally planted populations we want to test the hypothesis whether morphological divergence of alpine and foothill populations has a genetic basis or is driven by phenotypic plasticity. The presented thesis is an important multidisciplinary combination of genetic research on natural related of model...

When an animal’s pigmentation matches the background across various types of environments, it is potentially an example of cryptic pigmentation, most likely as a response to natural selection by visually oriented predators. One example of cryptic pigmentation is phenotypic plasticity, meaning that an organism can exhibit different phenotypes in different environments. The freshwater isopod Asellus aquaticusliving in stands of reeds tends to have darker pigmentation than individuals living amongst lighter-coloured stoneworts, which has been suggested to result from visual predation. A recent study showed, however, that pigmentation in A. aquaticus is partly plastic, influenced by the nutritional composition in their diet. Here, I performed a laboratory experiment on A. aquaticusto see if the nutritional composition in stoneworts decreases pigmentation. Isopods were provided with a diet of either decaying leaves or stoneworts. The experiment took place over four weeks and pigmentation and growth were analysed at 0, 15 and 31 days. I found that pigmentation in A. aquaticusincreased significantly on both diets. And, there was no difference between both diets in amount of change in pigmentation. The fact that isopods that were feeding on stoneworts did not become lighter to match their background colour preferably depend on a high nutritional composition in the provided food, considering they also more than doubled their weight. In other words, phenotypic plasticity due to different diets between habitats is not the explanation to lighter coloured isopods living amongst stoneworts. However, these results do not exclude that differences can arise over a longer time or differs between different species of stoneworts.

Le processus de biominéralisation confère aux organismes qui le développent une valeur adaptative. La coquille carbonatée des mollusques intègre les fonctions de protection biomécanique à différentes échelles. La coquille résulte de l'association de composés inorganiques et d'une matrice organique protéique, médiatrice du contrôle biologique de la minéralisation. L'analyse du protéome de la coquille chez 4 espèces de bivalves met en évidence deux patrons fonctionnels et leur degré de conservation phylogénétique : l'un lié au contrôle de la minéralisation stricto sensu ; l'autre à la protection immune. L'étude de populations vivant à l'état naturel en mer Baltique, dont les eaux présentent localement de fortes variations ioniques montre que le protéome intègre également l'impact de conditions environnementales limitantes. L'anthropocène impose un rythme adaptatif pressant aux organismes et la modification acido-basique des eaux océaniques est susceptible d'impacter sensiblement les organismes calcifiants. La signature de mécanismes adaptatifs du contrôle biologique de la biominéralisation se traduit dans le protéome de la coquille. Les implications sont particulièrement signifiantes dans un contexte d'intérêt de développement aquacole grandissant. / In this study, the SMPs from four commercially important and divergent bivalve species crassostrea gigas (pacific oyster), Mya truncata (soft shell clam), Mytilus edulis (blue mussel) and Pecten maximus (king scallop) were extracted and analysed using standardized extraction protocol and proteomic pipeline. This enables us to identify critical elements of basic biomineralization tool kit for calcification process irrespective of their shell morphology, mineralogy and microstructure. In addition, it enables the identification of SMPs that are specific to calcite and aragonite mineralogies. The signifiant numbers of SMPs found species-specific were hypothesized as adaptation to their modus vivendi. In fact, the latter proteins possess immunity-related functions and fit into specific pathway, phenoloxidase, suggesting their role in defense against pathogen. The comparative study of shell proteome of mussels living in full marine condition, North Sea and the Iow saline Baltic Sea showed the modulation of the SMPs that constitute the basic biomineralization tool kit. Higher modulation of chitin related proteins and non-modulated protein such as carbonic anhydrase, EGF and fibronectin domain containing proteins points out the impaired scaffold and mineral nucleation process in Baltic mussel. The modulation of immunity related proteins denote the influence of biotic components. These investigations show the functional diversity of SMPs and their roles beyond shell formation in the bivalvesand put forth the idea that shell is dynamic, endowed with both biochemical and mechanical protection.

A diversidade de estruturas de captura de presas (tentáculos e braços orais) em medusas adultas está associada a diferentes mecanismos de captura e hábitos alimentares. O entendimento do desenvolvimento dessas estruturas pode esclarecer a mecânica da alimentação e, consequentemente, aumentar o conhecimento sobre as consequências tróficas dos recorrentes blooms de cifomedusas. No entanto poucos estudos descrevem o desenvolvimento inicial das estruturas de captura e sua interação com o ambiente fluido (i.e., número de Reynolds, Re). Em vista disso, o objetivo deste trabalho foi descrever os estágios de desenvolvimento em espécies de Rhizostomeae (Mastigias papua, Cassiopea sp., Cotylorhiza tuberculata, Catostylus townsendi, Catostylus mosaicus, Lychnorhiza lucerna, Phyllorhiza punctata e Rhopilema esculentum) e \"Semaeostomeae\" (Chrysaora plocamia e Aurelia cf. sp. 4), com foco na umbrela e nos braços orais (capítulo 1); testar a hipótese de que diferentes temperaturas durante o crescimento geram desenvolvimento diferenciado da umbrela e dos braços orais, que compensariam o efeito da camada limite sob baixas temperaturas (i.e., baixo Re) para o funcionamento efetivo dessas estruturas como filtros coletores (capítulo 2); caracterizar a distribuição da epiderme ciliada e os fluxos produzidos em éfiras e medusas jovens de Lychnorhiza lucerna, medir a espessura da camada de água que os cílios conseguem mover e calcular o Re em torno dos digitata coberto por cílios (capítulo 3). Para isso as éfiras foram submetidas a tratamentos específicos e fotografadas até completarem 35 dias de idade e foi filmado o transporte de partículas pela epiderme ciliar. Concluímos que a caracterização do desenvolvimento inicial de distintas linhagens de éfiras de Scyphozoa possibilitou o conhecimento da morfologia das medusas, i.e., de suas estruturas natatórias e alimentares, propiciando, assim o entendimento de suas funções. Por sua vez, cifomedusas se mostraram resilientes às variações de temperatura, exibindo um crescimento diferenciado que deve garantir a manutenção das funções das estruturas natatórias e alimentares. A epiderme ciliar está presente ao longo de toda a medusa e moveu uma camada de água de até 0,28 mm. O batimento ciliar colabora com o mecanismo alimentar com o transporte de partículas e atua na dinâmica de mecânica de fluidos por criar fluxos na mesma direção do fluxo gerado pelas contrações umbrelares, ajudando a diminuir o efeito da camada limite. Por fim, ressaltamos que este trabalho mostrou a relevância de se estudar conjuntamente o desenvolvimento morfológico, o comportamento e a mecânica de fluidos para se compreender de forma complementar os mecanismos subjacentes à ecologia alimentar de importantes predadores marinhos como as medusas de Scyphozoa / The diversity of prey capture structures (tentacles and oral arms) in adult jellyfish is associated with different capture mechanisms and feeding habits. The understanding of these structures development can clarify the feeding mechanics and, consequently, increase the knowledge about the trophic consequences of the recurrent jellyfish blooms. However, few studies describe the capture structures initial development and their interaction with the fluid environment (i.e., Reynolds number, Re). The objective of this work was to describe the development stages in Rhizostomeae (Mastigias papua, Cassiopea sp., Cotylorhiza tuberculata, Catostylus townsendi, Catostylus mosaicus, Lychnorhiza lucerna, Phyllorhiza punctate and Rhopilema esculentum) and \"Semaeostomeae\" (Chrysaora plocamia and Aurelia cf. sp. 4) species, focusing on the bell and oral arms (chapter 1); to test the hypothesis that different temperatures during growth generate a differentiated development of the bell and oral arms, which would compensate for the boundary layer effect under low temperatures (i.e., low Re) for the effective functioning of these structures as collector filters (Chapter 2); to characterize the distribution of the ciliated epidermis and the flows produced in ephyrae and young jellyfish of Lychnorhiza lucerna, to measure the water layer thickness that the cilia can move and to calculate the Re around the digitata covered by cilia (Chapter 3). For this, the ephyrae were submitted to specific treatments and photographed until they were 35 days old and the transport of particles through the ciliary epidermis was filmed. We conclude that the initial development characterization of different strains of Scyphozoa ephyrae makes it possible to know the morphology of jellyfish, i.e., their swimming and feeding structures, thus providing an understanding of their functions. On the other hand, scyphomedusa showed to be resilient to the temperature variations, exhibiting a differentiated growth that must guarantee the maintenance of the swimming and food structures functions. The ciliary epidermis is present throughout the jellyfish and has moved a layer of water up to 0.28 mm. The ciliary stroke collaborates with the food mechanism with the transport of particles and acts on the dynamics of fluid mechanics by creating flows in the same direction of the flow generated by the bell contractions, helping to diminish the effect of the boundary layer. Finally, we highlight that this work showed the relevance of jointly studying the morphological development, behavior and fluid mechanics to comprehend in a complementary way the mechanisms underlying the food ecology of important marine predators such as Scyphozoa jellyfish

Os efeitos negativos da ocorrência de baixas temperaturas sobre o arroz são de difícil controle e manejo, por ser um fator imprevisível. Embora não seja uma tarefa fácil, em diversas regiões do mundo, já foram desenvolvidas cultivares com adequada tolerância ao frio. O caminho para o desenvolvimento de cultivares deve envolver, a adoção de várias estratégias para tornar o processo de melhoramento desse caráter ágil e preciso. O objetivo deste trabalho foi avaliar a diversidade genética existente entre os acessos de arroz da subespécie Japonica do Banco de Germoplasma da ESALQ/USP e caracterizá-los a fim de identificar fontes de tolerância ao frio durante a fase reprodutiva. O trabalho foi conduzido em dois anos agrícolas sendo o primeiro experimento em 2013 e o segundo em 2014. No primeiro experimento, foi feita a identificação da diversidade genética por caracteres agromorfológicos e a avaliação do seu rendimento em condições de estresse por baixas temperaturas na fase reprodutiva. A divergência genética entre os acessos foi quantificada por meio de análises estatísticas multivariadas, sendo que foi utilizada a distância generalizada de Mahalanobis. O método de agrupamento utilizado foi o algoritmo de otimização de Tocher e foi feita análise de componentes principais para determinar as variáveis que mais contribuíram para a variabilidade dos acessos. No segundo experimento, os genótipos que apresentaram bom desempenho foram avaliados novamente a fim de identificar aqueles tolerantes ao frio na fase reprodutiva. Foi observada a presença de variabilidade genética para os caracteres avaliados. No primeiro experimento, os acessos japoneses apresentaram em média maior rendimento e massa de mil grãos e menor esterilidade quando comparados com as cultivares comerciais, indicando possível existência de fontes de tolerância ao frio na fase reprodutiva. Considerando simultaneamente as variáveis analisadas, de acordo com o algoritmo de otimização de Tocher, os acessos e cultivares foram reunidos em 37 grupos de similaridade. Os genótipos avaliados no segundo experimento apresentaram elevada esterilidade (próxima a 100%). No entanto, deve-se destacar que foram registradas temperaturas críticas baixas (inferiores a 15°C) ao longo de quase todo o ciclo, especialmente durante o período reprodutivo. / Being an unpredictable factor, the negative effects of occurrence of low temperatures on rice are difficult to control and managed. Although it is not an easy task, in various regions of the world, cultivars have been developed with adequate cold tolerance. The path to the development of cultivars should involve the adoption of various strategies to make the process of improvement of this character more agile and precise. The objective of this study was to evaluate the genetic diversity among rice accessions of Japonica subspecies of the Germplasm Bank of ESALQ / USP and characterize them morphological in order to identify sources of cold tolerance during the reproductive phase. The work was conducted in two years with the first trial in 2013 and the second in 2014. In the first trial, the identification of the genetic diversity of agronomic characters and the evaluation of its performance under stress conditions by low temperatures in the reproductive phase. The genetic divergence among accessions was quantified by means of multivariate statistical analysis, using the Mahalanobis distance. The clustering method used was Tocher optimization algorithm and it was also performed made principal component analysis to determine the variables that contributed the most to the variability of accessions. In the second trial, the genotypes that performed better were evaluated again in order to identify those that were cold tolerant in the reproductive phase. It was observed the presence of genetic variability for all the characters. In the first trial, the Japanese accessions showed on average higher yield and thousand grain weight, and also less sterility compared to commercial cultivars, which may indicate the existence of cold tolerance sources in the reproductive phase. Considering the variables analyzed, according to the Tocher optimization algorithm, accessions and cultivars were divided into 37 groups of similarity. The genotypes used in the second test showed high sterility (close to 100%). However, it should be noted that low critical temperatures were recorded (below 15 ° C) over almost the entire cycle, especially during the breeding season.

As moscas-das-frutas são pragas da fruticultura nas regiões tropicais e subtropicais sendo que a Anastrepha fraterculus (Diptera, Tephritidae) é a espécie de maior importância econômica na Região Neotropical. Na realidade, A. fraterculus corresponde a um complexo de espécies crípticas que apresentam variações com relação ao uso de plantas hospedeiras. O presente estudo teve como objetivo investigar se a utilização de diferentes frutos hospedeiros resulta em diferenças morfológicas e/ou reprodutivas em indivíduos de amostras populacionais de A. sp.1 aff. fraterculus derivadas de diferentes frutos hospedeiros coletados em áreas de simpatria. Foram realizadas análises (a) morfológicas das asas e de conjuntos de cerdas da cabeça, além da descrição dos tipos de sensilas dos flagelos das antenas e (b) da escolha de parceiros reprodutivos entre espécies provenientes de diferentes frutos hospedeiros. As análises de morfometria mostraram variação nas asas relacionadas a diferentes frutos e que o grau de assimetria das estruturas varia entre as diferentes amostras. As análises dos tricomas das asas mostraram que não existe variação numérica de células entre as asas com formas diferentes, indicando que essa variação deve ser devida a diferenças na forma e/ou tamanho das células. As análises de assimetria flutuante em relação ao número de cerdas da cabeça indicaram diferenças entre as amostras. Em relação à assimetria posicional das cerdas, as populações apresentaram diferentes graus de assimetria. A análise das sensilas mostrou que existem diferenças na distribuição de cada tipo ao longo do flagelo, sendo a maior variação na região mediana, mas para quatro dos tipos não foram observadas diferenças nas amostras dos diferentes frutos. No experimento de escolha de parceiro reprodutivo houve uma tendência das fêmeas em escolher machos provenientes do mesmo fruto hospedeiro. No experimento de troca de fruto hospedeiro com uma população de laboratório, os resultados mostraram que houve um decréscimo na taxa de emergência de adultos, além de outros que apresentaram malformações. Os efeitos provocados por essa mudança de substrato do desenvolvimento larval foram distintos para as asas e cerdas, havendo manifestação no aumento da assimetria flutuante apenas nessas últimas. A diferença de resposta das estruturas pode resultar de distinção na robustez dos mecanismos que promovem a estabilidade ontogenética dessas estruturas. No presente estudo foi possível avaliar que o fruto hospedeiro no qual a larva se desenvolve, influencia a morfologia das asas, o reconhecimento de parceiros reprodutivos e pode ser um fator de estresse durante a ontogenia de A. sp.1 aff. fraterculus / The fruit flies of Tephritidae family are insect pests distributed around the tropical and subtropical regions of the world. Among these flies, Anastrepha fraterculus is one of the most important pest species in the Neotropical Region. In reality, A. fraterculus correspond to a complex of cryptic species that shows differences in relation to the usage of host plants for larval development. The present study aimed to investigate if the use of distinct host fruits causes morphological and/or reproductive alterations in individuals from population samples of A. sp.1 aff. fraterculus derived from distinct sympatric fruits. To attain this goal, two series of experiments were conducted: (a) morphological analyses of the wings and of head bristles, besides the description of the sensilla types in the flagellum, and (b) tests on choice of reproductive partners derived from different host fruits. Morphometric analyses show variation in the wings to be associated to distinct fruits and that asymmetry vary among samples. The number of trichomes was invariable in the wings exhibiting subtle morphological distinctions, indicating that the differences might be due to shape and/or size of the cells. Fluctuating asymmetry in the number and position of head bristles is varied significantly among the flies derived from distinct fruits. The analysis on the distribution of sensilla along the flagellum revealed that the distribution of each one is distinct, most of variation occurring at the median region; however for four sensilla types no differences were detected. Experiments on mating choice showed a tendency of females to elect males derived from the same fruit type. The experiments on effects of host fruit changing in a laboratory colony of flies showed that a decrease in adult emergence did occur. An increase in the number of malformed adults was observed. The observed effects of changing the substrate for larval development were distinct for wings and bristles with an increase in the asymmetry of the latter. The distinction in response of the structures is suggestive that differences may exist in the robustness of the mechanisms that afford ontogenetic stability of wings and bristles. The present study indicates that the fruit in which the larvae develop has influence in the morphology of the wings, in the recognition of reproductive partners and may be a stressing factor during the ontogeny of A. sp.1 aff. fraterculus

Caracteres fenotípicos convergentes em diferentes espécies de insetos herbívoros sugerem uma adaptação funcional a um mesmo hábito alimentar. Nesse sentido, as barreiras apresentadas pelas plantas dificultam o acesso do herbívoro influenciando a evolução de suas estruturas. Espécies de Heliconiini com diferentes padrões alimentares (consumo de tecidos rígidos ou tenros) têm mostrado formas diferenciadas da cápsula cefálica e não existe estudo que explique essas diferenças. Levando em conta que os heliconíneos menos derivados tendem a se alimentar em folhas velhas e os mais derivados em folhas jovens, e que durante o processo de alimentação a mandíbula é a estrutura principalmente associada à mastigação, propomos que dito aumento da cabeça seja devido a modificações sofridas na forma mandibular e ao maior desenvolvimento do músculo adutor da mandíbula, que responde diferencialmente ao tipo de tecido consumido. Avaliamos as alometrias ontogenética e filogenética das mandíbulas das principais linhagens de Heliconiini criadas nas suas plantas hospedeiras preferidas, e mediante o uso de morfometria geométrica, elaboraremos uma proposta filogenética para ser comparada com as relações filogenéticas reconhecidas para o grupo, que também serão reconstruídas nesse trabalho, com base em marcadores moleculares. Identificamos também mediante a morfologia mandibular se as alterações de forma são causadoras das mudanças cefálicas e se correspondem aos diferentes hábitos alimentares apresentados pelas espécies. Para isso, induzimos alometría mudando quanto o comportamento alimentar de uma espécie restrita a folhas novas (tenras) para folhas velhas (rígidas), na procura de possíveis modificações nas mandíbula e músculo adutor. Adicionalmente, usando análises alométricas da mandíbula e músculo adutor, exploramos um aspecto comportamental importante em Heliconiini: a gregariedade, buscando elucidar se o incremento na sobrevivência obtida a altas densidades larvais, já reconhecida no grupo, é ocasionada por facilitação alimentar (comportamento) ou por mudanças alométricas nas estruturas alimentares (morfologia). / Convergent phenotypic traits in different species of herbivorous insects may indicate a functional adaptation to the same feeding habits. The barriers presented by plants hinder the herbivore's access, influencing the evolution of their feeding structures; species of Heliconiini with different feeding patterns (consumption of either tough or soft tissues) have shown different forms of head capsule and there are no studies explaining these differences. Taking into account that the less derived heliconians tend to eat old leaves and the more derived heliconians eat young ones, and that during the feeding process the mandible is main chewing structure, we propose that increase in head size is due to changes in the mandibular form and to greater development of the mandibular adductor muscle that responds differentially to the type of tissue consumed. We evaluate ontogenetic and phylogenetic allometries of the mandibles from the main lineages of Heliconiini that were reared on their favorite host plants. By using geometric morphometry, we tested a corresponding phylogenetic hypothesis to be compared to the molecular phylogenetic relations recognized to the group, also reconstructed in this work based on molecular markers. We also tested, through mandibular morphology, if the changes in shape are caused by cephalic changes in size and if they correspond to the different feeding habits presented by each species. To do this, we induced allometry by experimentally altering feeding behavior of one species restricted to new leaves (soft) to old leaves (tough), searching for possible changes in the mandible and adductor muscle. In addition, using allometric analysis of the mandible and adductor muscle, we explored an important behavioral aspect in Heliconiini -the gregariousness, trying to elucidate whether increase in the survival rates achieved at high larval densities, already recognized in the group, is caused by food facilitation (behavioral effect) or by allometric changes in the feeding structures (morphological cause).

O aerênquima é um tecido vegetal com grandes lacunas de ar que podem ter função de circulação de gases e/ou sustentação de órgãos, estando presente nas raízes e órgãos aéreos de plantas aquáticas ou sob alagamento, podendo ainda ser formado em decorrência de algum estresse. Ceratopteris richardii é uma planta aquática, de hábito anfíbio que apresenta aerênquima em seus órgãos vegetativos. Dessa forma, esse trabalho buscou analisar a formação de aerênquima nas raízes e pecíolo desta espécie frente a uma situação de restrição hídrica e verificar sua plasticidade fenotípica. Vinte indivíduos de C. richardii foram cultivados e submetidos a um tratamento com diferentes concentrações de PEG 6000. Em todas as amostras analisadas, foi observada a formação de aerênquima. A análise qualitativa mostrou diferença entre os tratamentos, porém, a análise estatística revelou que as diferenças não são significativas para o número amostral empregado. Variações de crescimento do esporófito revelaram que a espécie de estudo modificou algumas características de desenvolvimento em resposta a restrição hídrica. Tais resultados revelam importantes características para esta espécie, que parece aclimatar-se a situação de estresse a qual foi submetida. Com base nisso, sugere-se ampliar estes estudos para elucidar questões relacionadas a formação de aerênquima e o ambiente, seja para esta espécie ou de outro grupo taxonômico. / Aerenchyma is a plant tissue with large air gaps that may have gas circulation function and / or sustain organs. This structure is present in roots and aerial organs of water plants and in plants under flooding it may also be formed during some stress. Ceratopteris richardii is an aquatic plant, with amphibious habit that has aerenchyma in their vegetative organs. Thus, the aim of this study is analyze the aerenchyma formation in roots and stem of this specie under water restriction situation and verify their phenotypic plasticity. Twenty specimen of C. richardii were cultured and subjected to treatment with different concentrations of PEG 6000. In all samples, were observed aerenchyma formation. Qualitative analysis showed differences among treatments, however, the statistical analysis revealed that the differences are not significant for the sample size. Sporophyte growth variations revealed that the specie of study modified some growth characteristics in response to water restriction. These results reveal important characteristics for C. richardii, which seems to acclimatize the stress situation which has submitted. On the base that, it is suggested further studies to become clearer the relation between aerenchyma formation and environment, even to either this species or another taxonomic group.

La levure S. cerevisiae est la seule espèce capable de terminer la fermentation alcoolique du jus de raisin qui est l’étape principale de la vinification. A cause de la forte variabilité technologique retrouvée chez cette espèce, des travaux de sélection sont réalisés dans le but d’utiliser des levains performants pour l’industrie. Ces souches montrent des différences importantes à la fois dans leurs cinétiques fermentaires et leur bilans en métabolites, ce qui impacte la qualité des vins. La réponse phénotypique des levures varie également de manière considérable et non homogène face aux variations environnementales. La compréhension des mécanismes génétiques expliquant cette réponse différenciée est une question scientifique non triviale. Elle revêt une importance particulière en oenologie, où les conditions de vinifications sont très changeantes (millésimes, cépages, terroirs, conduites de vinifications…). Afin de pouvoir proposer des levains garantissant le succès des fermentations dans un large éventail de conditions, nous proposons ici de mieux comprendre ces mécanismes d’interaction Gène x Environnement dans un contexte oenologique. L’identification de locus génétiques (Quantitative Trait Loci (QTL)) contrôlant des caractères quantitatifs est rendue possible par des approches de cartographie de QTLs. Celles-ci nécessitent l’étude d’une vaste descendance en ségrégation qui doit être caractérisée sur le plan génétique et phénotypique. L’établissement d’un lien statistique entre des marqueurs génétiques et un phénotype permet la localisation de QTLs influant les caractères étudiés. Au cours de cette thèse, une méthode de phénotypage pour suivre les fermentations de plusieurs centaines d’individus a été mise au point. Grâce à elle, les performances fermentaires de deux descendances génotypées par séquençage à haut débit ont été mesurées en faisant varier les conditions de fermentations. Cela a permis l’identification de nombreux QTLs et d’estimer leur impact sur la robustesse des souches. L’implication des allèles de trois gènes qui montrent une forte interaction avec l’environnement et qui possèdent des effets pléiotropiques liés au métabolisme du SO2 a été prouvée moléculairement. Les résultats obtenus font l’objet d’une discussion générale sur l’utilisation de QTLs pour la sélection de levures plus performantes. / The yeast S. cerevisiae is the only species able to complete the alcoholic fermentation of grape must which is the main step of the wine-making process. Because of the high technological variability found in this species, selection work is carried out with the aim of using efficient yeasts for the industry. These strains show important differences both in their fermentation kinetics and their metabolite yield which affects the wines quality. In addition to these important phenotypic variations, the phenotypic response of yeasts varies considerably and not homogeneously against environmental variations. Understanding the genetic mechanisms that explain these differentiated responses to environmental variations is a non-trivial scientific question. This is of particular importance in oenology, where the winemaking conditions are highly variable (vintages, grape variety, terroirs, oenological practices...). In order to obtain yeasts ensuring the success of the fermentations under a wide range of conditions, we propose here to better understand these mechanisms of interaction Gene x Environment in an oenological context. The identification of genetic locus (Quantitative Trait Loci (QTL)) controlling quantitative characters is made possible by QTL mapping approaches. These approaches require the study of a large progeny in segregation that must be characterized genetically and phenotypically. The establishment of a statistical link between genotype and phenotype allows the localization of QTLs that have an impact on phenotyped characters. During this thesis a phenotyping method that allows us to follow the fermentations of several hundred individuals has been developed. Thanks to it, two progenies genotyped by whole genome sequencing have been phenotyped in different environmental conditions. This lead to the identification of many QTLs and to the estimation of their impact in strain robustness. The implication of the alleles of 3 genes showing a strong interaction with environment and pleiotropic effects linked to the SO2 metabolism has been proved molecularly. The results achieved are discussed in the context of QTL exploitation for the selection of more efficient yeast.