Plants produce a vast number of low-molecular-weight chemicals (so called secondary or specialized metabolites) that confer a selective advantage to the plant, such as defense against herbivory or protection from changing environmental conditions. Many of these specialized metabolites are used for their medicinal properties, as lead compounds in drug discovery, or to impart our food with different tastes and scents. These chemicals are produced by various pathways of enzyme-mediated reactions in plant cells. It is suspected that enzymes in plant specialized metabolism evolved from those in primary metabolism. Understanding how plants evolved to produce these diverse metabolites is of primary interest, as it can lead to the engineering of plants to be more resistant to both biotic and abiotic stress, or to produce more complex small molecule compounds that are difficult to derive. To that end, the first objective was to develop a schema for rational protein engineering using meta-analyses of a well-characterized sesquiterpene synthase family encoding two closely-related but different types of enzymes, using quantitative measures of natural selection on amino-acid positions previously demonstrated as important for neofunctionalization between two terpene synthase gene families. The change in the nonsynonymous to synonymous mutation rate ratio (dN/dS) between these two gene families was large at the sites known to be responsible for interconversion. This led to a metric (delta dN/dS) that might have some predictive power. This natural selection-oriented approach was tested on two related enzyme families involved in either nicotine/tropane alkaloid biosynthesis (putrescine N-methyltransferase) or primary metabolism (spermidine synthase) by attempting to interconvert a spermidine synthase to encode putrescine N-methyltransferase activity based upon past patterns of natural selection. In contrast to the HPS/TEAS system, using delta dN/dS metrics between SPDS and PMT and site directed mutagenesis of SPDS did not result in the desired neofunctionalization to PMT activity. Phylogenetic analyses were performed to investigate the molecular evolution of plant N-methyltransferases involved in three alkaloid biosynthetic pathways. The results from these studies indicated that unlike O-MTs that show monophyletic origins, plant N-MTs showed patterns indicating polyphyletic origins. To provide the foundation for future molecular-oriented studies of urushiol production in poison ivy, the complete poison ivy root and leaf transcriptomes were sequenced, assembled, and analyzed. / Ph. D.

Bumblebees are important pollinators, commercially used in large-scale plant growing in greenhouses. Their males produce marking pheromones for mating, which attract young bumblebee queens. These pheromones are often a complicated mixture of chemicals, which is produced in the male labial gland, and the mixture itself is specific for each bumblebee species. The regulation of bumblebee sexual pheromone biosynthesis is largely unknown, and this Master's thesis is focused on the analysis of the mechanisms which lead to the regulation of the Bombus terrestris male pheromone's fat-acid and terpenes biosynthesis, specifically on stereospecific enzymatic reduction of double bond of farnesol. This thesis studies the influence of potential neurohormones on a specific enzymatic mixture, which is involved in the pheromone biosynthesis. Methods used in this project include biochemical, analytic and molecular-biology methods.

L'utilisation des matières premières renouvelables dans la synthèse des molécules organiques ou les additifs alimentaires, les pesticides et les polymères a trouvé un intérêt croissant ces dernières années pour des raisons économiques aussi bien qu'écologiques. Au cœur des produits naturels on trouve les terpènes provenant essentiellement des bioressources et représentant une grande famille de molécules naturelles. Ils offrent un potentiel important pour l'accès à des produits à haute valeur ajoutée en utilisant des outils catalytiques sélectifs, tout en respectant le principe d'économie d'atomes. Les réactions cascades basées sur les processus d’(auto)transfert d'hydrogène, générant uniquement de l'eau et des sels non toxiques comme produits secondaires sont particulièrement propres, efficaces et attractives du point de vue de la valorisation durable des terpènes. Dans ce contexte, nous avons développé un nouveau système catalytique et efficace pour l’amination réductrice des alcools allyliques en présence de différentes amines en utilisant des complexes de ruthénium(II). Cette méthode a été appliquée à une large gamme d'alcools allyliques terpéniques tels que le géraniol, le nérol et le phytol, ce qui a permis leur valorisation d’une façon chimiosélective, ne générant que l’eau et le dioxyde de carbone comme sous produits bénins. La fonctionnalisation sp3 C-H des azaterpènes cycliques a été ensuite réalisée avec différents terpènes aldéhydes en présence de complexe de ruthénium(II). Ces transformations ont permis la production d'une petite librairie de N-et C-azaterpenes. Certains de ces terpènes alcaloïdes ont montré une bonne activité antibactérienne. Par la suite, la synthèse de nouveaux complexes chiraux [Ru(Cp’)] (IV) à partir de (+)-nopinone, un monoterpène issu de l’oxydation de β-pinène a été réalisée. L'application de ces complexes dans l'allylation asymétrique de carbonate de cinnamyle par le phénol a montré une bonne régio- et énantiosélectivité. / The use of renewable feedstock in the synthesis of organic molecules such as food additives, pesticides and polymers, has found increasing interest over recent years due to economic as well as ecological reasons. At the heart of natural products are terpenes derived essentially from bioresources and they represent a large family of natural molecules, which have a moderate cost. They offer a significant potential for the access to products with high added value using selective catalytic tools, respecting the principle of atom economy. Catalytic reactions involving hydrogen (auto)transfer, generating only water and non-toxic salts as byproducts are particularly clean, efficient and attractive methods from a sustainable point of view for the valorization of terpenes. In this context we have developed a new and efficient catalytic system for reductive amination of allylic alcohols in the presence of various amines using arene ruthenium(II) complex. The application of this method to a wide range of terpenic allylic alcohols like geraniol, nerol and phytol allowed the formation of new azaterpenes in good yield and high chemoselectivity generating only water and carbon dioxide as benign side products. The sp3 C–H functionalization of N-terpenylated cyclic amines was then performed with various terpenaldehydes without side alkene reduction in the presence of arene ruthenium(II) catalyst. These eco-friendly transformations enable the production of a small library of N- and C- terpenylated amines. Some of these terpene alkaloids showed good antibacterial activities. The synthesis of new chiral [Ru(Cp’)] (IV) complexes featuring a N,O chelate were successful, using a chiral ligand derived from commercially available (+)-nopinone, a monoterpene derived from oxidation of β-pinene. The application of these complexes in the asymmetric allylation of cinnamyl carbonate by phenol gave high regioselectivity and satisfactory enantioselectivity.

This thesis describes methods to obtain value–addedcompounds from TMP-turpentine obtained from the spruce, Piceaabies. The methodology focuses on biotransformations using twoapproaches: an oxygenation approach (i.e. oxygenation ofterpene hydrocarbons by cell cultures) and an esterificationapproach (i.e. lipase-catalysed transesterification of vinylacetate with terpene alcohols, and a further fractionation ofthe TMP-turpentine). The main constituents of the turpentine, a-pinene, b-pineneand limonene, were subjected to a P. abies suspension culture.Allylic oxidation formed the major products for α-pineneand β-pinene, which were further oxidised to theirrespective aldehyde or ketone. One of the minor products froma-pinene, cis-verbenol, was not only transformed into verbenonebut also isomerised to trans-verbenol. Limonene gavelimonene-(1,2)-epoxide as the major product. Fractionation of monoterpenes is accomplished throughphysical separation methods, chromatography and distillation,and lipase-catalysed transesterification of vinyl acetate withterpene alcohols. The esters of myrtenol and trans-pinocarveolwere separated from the more slowly reacting alcohols such asborneol and carveol by use of a combination of the Mucor mieheilipase and Candida antarctica lipase A as catalysts.Furthermore, the non-reacting tertiary terpene alcohols wereseparated from the reacting alcohols in a single step byCandida antarctica lipase A. Lipase-catalysed (Candida antarctica lipase B andPseudomonas cepacia lipase) transesterification of vinylacetate with sterically hindered secondary alcoholsunexpectedly yielded hemiacetals or hemiacetal esters. Thereaction conditions required to obtain these side products havebeen studied. <b>Keywords:</b>Picea abies, Pinaceae, Essential oilscomposition; Terpene alcohol; Hemiacetal; Hemiacetal ester,TMP-turpentine; Monoterpene; α-Pinene; β-Pinene;Limonene; Verbenol; Pinocarveol; Borneol; Myrtenol; Suspensioncell culture; Biotransformation; Lipase-catalysed; Oxidation;Allylic oxidation; Transesterification; Autoxidation;Separation.

<p>This thesis describes methods to obtain value–addedcompounds from TMP-turpentine obtained from the spruce, Piceaabies. The methodology focuses on biotransformations using twoapproaches: an oxygenation approach (i.e. oxygenation ofterpene hydrocarbons by cell cultures) and an esterificationapproach (i.e. lipase-catalysed transesterification of vinylacetate with terpene alcohols, and a further fractionation ofthe TMP-turpentine).</p><p>The main constituents of the turpentine, a-pinene, b-pineneand limonene, were subjected to a P. abies suspension culture.Allylic oxidation formed the major products for α-pineneand β-pinene, which were further oxidised to theirrespective aldehyde or ketone. One of the minor products froma-pinene, cis-verbenol, was not only transformed into verbenonebut also isomerised to trans-verbenol. Limonene gavelimonene-(1,2)-epoxide as the major product.</p><p>Fractionation of monoterpenes is accomplished throughphysical separation methods, chromatography and distillation,and lipase-catalysed transesterification of vinyl acetate withterpene alcohols. The esters of myrtenol and trans-pinocarveolwere separated from the more slowly reacting alcohols such asborneol and carveol by use of a combination of the Mucor mieheilipase and Candida antarctica lipase A as catalysts.Furthermore, the non-reacting tertiary terpene alcohols wereseparated from the reacting alcohols in a single step byCandida antarctica lipase A.</p><p>Lipase-catalysed (Candida antarctica lipase B andPseudomonas cepacia lipase) transesterification of vinylacetate with sterically hindered secondary alcoholsunexpectedly yielded hemiacetals or hemiacetal esters. Thereaction conditions required to obtain these side products havebeen studied.</p><p><b>Keywords:</b>Picea abies, Pinaceae, Essential oilscomposition; Terpene alcohol; Hemiacetal; Hemiacetal ester,TMP-turpentine; Monoterpene; α-Pinene; β-Pinene;Limonene; Verbenol; Pinocarveol; Borneol; Myrtenol; Suspensioncell culture; Biotransformation; Lipase-catalysed; Oxidation;Allylic oxidation; Transesterification; Autoxidation;Separation.</p>

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Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-04-04T13:14:56Z No. of bitstreams: 1 diegopandelojose.pdf: 913814 bytes, checksum: 7e149c7c8e0bee3253c4894426a6892c (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-04-04T15:36:35Z (GMT) No. of bitstreams: 1 diegopandelojose.pdf: 913814 bytes, checksum: 7e149c7c8e0bee3253c4894426a6892c (MD5) / Made available in DSpace on 2017-04-04T15:36:35Z (GMT). No. of bitstreams: 1 diegopandelojose.pdf: 913814 bytes, checksum: 7e149c7c8e0bee3253c4894426a6892c (MD5) Previous issue date: 2009-03-03 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico / FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais / O gênero Lippia pertence à família Verbenaceae, inclusa no clado Asteridaee, ordem Lamiales, compreendendo aproximadamente 175 gêneros e 2800 espécies, onde muitos gêneros apresentam plantas com propriedades medicinais e ornamentais. A espécie Lippia alba, originária da América do Sul, também ocorre no Brasil e é uma das mais estudadas do gênero Lippia. Ela floresce durante o ano todo e recebe grande destaque no gênero, devido às suas inúmeras propriedades medicinais. O óleo essencial de Lippia alba é composto basicamente por sesqui e monoterpenos, que são as substâncias responsáveis por suas propriedades medicinais. O objetivo central do presente trabalho foi clonar e analisar a expressão de dois potenciais genes codificadores de terpeno sintases em Lippia alba. Através do alinhamento de genes codificadores de monoterpeno sintases caracterizadas, primers degenerados foram desenhados dentro de regiões conservadas e utilizados para se obter a clonagem de genes codificadores de terpeno sintases em Lippia alba. Dois potenciais genes codificadores de terpeno sintases foram clonados, LaTPS12 e LaTPS23. Após a clonagem, técnicas de RT-PCR semiquantitativo foram empregadas para análises de expressão desses dois genes em diferentes estágios foliares e em três diferentes quimiotipos de Lippia alba. Os resultados mostraram que em folhas situadas no quarto segmento nodal o gene LaTPS12 apresenta maior nível de expressão. A diferença na expressão do gene LaTPS23 foi menos acentuada nos três quimiotipos analisados em relação ao gene LaTPS12, que apresentou uma expressão diferencial. Análises filogenéticas foram realizadas comparando-se as seqüências desses dois genes com outros genes codificadores de terpeno sintases já caracterizadas de diferentes espécies de plantas. De acordo com essas análises, LaTPS12 e LaTPS23 pertencem à classe TPS-b, que é composta principalmente por monoterpeno sintases de angiospermas. / The genus Lippia belongs to Verbenaceae family, Asteridaee, order Lamiales. This family comprises about 175 genus and 2800 species, and many of them have medicals and ornamentals proprierties. Lippia alba is native from South America, and is also found in Brazil and is the most studied species of the genus Lippia. This plant blooms throughout the year and has great importance due to its medicinal properties. The Lippia alba essential oils are composed by sesquiterpenes and monoterpenes conferring its medicinal properties. The aim of this work was to clone and to analize gene expression of putative terpene synthases genes (TPS) in Lippia alba. Alignment of TPS genes was used to design degenerate primers into conserved domains for cloning of these genes in Lippia alba. We have cloned two putative TPS genes, LaTPS12 and LaTPS23. After cloning, semiquantitative RT-PCR was employed to expression analysis of these two genes in different leaf stages and among three different chemotypes of Lippia alba. The result of expression level showed that LaTPS12 occurred at higher level in leaves located in fourth nodal segment and showed a marked differential expression among the chemotypes. The difference of expression of the LaTPS23 was less prominent comparing the three studied chemotypes. We performed a phylogenetic analysis in order to compare the LaTPS12 and LaTPS23 to others TPS genes in different plant species. The results showed that these LaTPS12 and LaTPS23 belong to the class TPS-b, which comprises mainly angiosperms monoterpene synthases genes.

In der vorliegenden Arbeit wird die Anwendung der Lewis-Säure vermittelten Cycloadditionen von Allylsilanen an alpha,beta-ungesättigte Carbonylverbindungen beschrieben. Das Sesquiterpen Isocomen wurde unter Anwendung der [3+2]-Cycloaddition an Enone synthetisch hergestellt. Die [2+2]-Cycloaddition an Acrylsäurederivate wurde angewandt für einen Einstieg zur Totalsynthese des Oleander Scale Pheromons. Im zweiten Teil der Arbeit wird die Synthese hormonell aktiver Cholesterinderivate dargestellt. Ausgehend von kommerziell erhältlichen Substanzen wurden verschiedene Substituenten in das Steroidgerüst eingeführt.

Submitted by isabela.moljf@hotmail.com (isabela.moljf@hotmail.com) on 2017-06-21T14:43:48Z No. of bitstreams: 1 viniciuscariusdesouza.pdf: 3785363 bytes, checksum: 7063d6c5f5cef353643903ad5f125c48 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-08-07T19:09:52Z (GMT) No. of bitstreams: 1 viniciuscariusdesouza.pdf: 3785363 bytes, checksum: 7063d6c5f5cef353643903ad5f125c48 (MD5) / Made available in DSpace on 2017-08-07T19:09:52Z (GMT). No. of bitstreams: 1 viniciuscariusdesouza.pdf: 3785363 bytes, checksum: 7063d6c5f5cef353643903ad5f125c48 (MD5) Previous issue date: 2016-03-03 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico / FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais / Lippia alba, popularmente conhecida por erva-cidreira, é uma espécie vegetal amplamente distribuída pelas Américas e encontrada praticamente em todo o território brasileiro. Esta espécie possui importante uso na medicina tradicional para o tratamento de cólicas, indigestão, náuseas, espasmos, diarreia, disenteria, doenças respiratórias, problemas hepáticos e no tratamento de sífilis e gonorreia. As folhas de L. alba, as quais são preparadas sob a forma de infusão ou decocção e ingeridas por via oral, produzem um óleo essencial rico em moléculas iso-prenóides denominadas terpenóides. Estes compostos não são apenas de interesse farmacológico, mas também industrial já que são usados na confecção de fragrâncias. A composição dos óleos essenciais pode variar em função de diferentes fatores abióticos e genotípicos, como por exemplo nível de ploidia. Neste contexto, os objetivos deste trabalho foram caracterizar o transcriptoma de folha da espécie L. alba e buscar sequencias putativas de enzimas envolvidas na produção de metabólitos secundários. O transcriptoma foi sequenciado pela plataforma Miseq (Illumina) com bibliotecas pairedend de 300 bp. O sequenciamento resultou em um total de 47.498.310 reads paired-end (23.749.155 reads para cada end sequenciado) de 35-308 bp, compreendendo 12.148.327.567 nucleotídeos (-12 Gb). A montagem de novo dos transcritos foi processada a partir do software Trinity que gerou 193.532 transcritos, sendo 128.209 unigenes, com o valor de N50 igual a 1.187 bp. Um total de 86.122 ORF (Open Read Frame) foi obtido e a seguir submetido ao algoritmo de alinhamentos BlastP, o qual encontrou 75.533 sequências com referência no banco de dados NR (Non-Redundant) de proteínas. Aproxima-damente, 78,4% dessas sequências foram anotadas funcionalmente a partir do pipeline utiliza-do pelo software Blast2GO. As análises das sequências anotadas revelaram prováveis enzimas para síntese de terpenóides como geraniol e linalol/nerolidol. Para validação da montagem e anotação, foram realizados ensaios de qPCR para amplificação de sequências de 13 genes para controles endógenos e 4 genes de terpeno sintases. Os resultados obtidos aqui corroboram outros estudos de transcriptoma de espécies não modelo usando tecnologias de sequenciamento de alto-desempenho. / Lippia alba, popularly known as erva-cidreira, is a widely distributed specie in Americas and it is found throughout Brazil. This specie has important using in popular medicine for cramp-ing, indigestion, nausea, diarrhea, dysentery, respiratory diseases, liver disorders treatment and infectious diseases such as syphilis and gonorrhea. The leaves of L. alba, which are pre-pared by infusion or decoction and orally ingested, producing an essential oil rich in terpene compounds. These compounds are of pharmacological and industrial interest, due to their use in fragrance preparation. Interestingly, the composition of essential oils change according to different abiotic factors and genetic variations such as ploidy level. In this context, the aims of this work were to characterize the transcriptome of leaves of L. alba (linalool chemotype) and to search putative enzymes sequences involved in production of secondary metabolites. The transcriptome was sequenced by Miseq platform (Illumina) running pair-end libraries 300 bp. The sequencing resulted in 47,498,310 reads (23,749,155 reads for each end sequenced) of 35-308 bp, comprising 12,148,327,567 nucleotides (-12 Gb). The de novo assembly of tran-scripts was processed by Trinity software and generated 193,532 transcripts, in 128,209 uni-genes, with N50 equal to 1,187 bp. 86,122 ORFs (Open Read Frame) were obtained and sub-mitted to BlastP algorithm, finding 75,533 sequences included in NR (Non-Redundant) pro-tein database. Approximately 78.4% of these sequences were functionally annotated using Blast2Go pipeline. Analysis of annotated sequences revealed putative enzymes for synthesis of terpenoids such as geraniol and linalool/nerolidol. For assembly and annotation validation, qPCR assay were realized by amplification of 13 endogenous control genes and 4 terpene synthases genes. The results found here corroborate transcriptome studies in non-model or-ganisms using high-performance sequencing technologies.

Pelargonium sp., appelé aussi « géranium » à odeur de rose ou « Géranium rosat » est l’une des plantes aromatiques et médicinales les plus cultivées au niveau international, essentiellement pour son huile essentielle (HE), utilisée par les industries des cosmétiques et de la parfumerie. Cette essence est extraite des feuilles par distillation vapeur et donne une HE riche de plusieurs centaines de molécules volatiles. Cette complexité est le résultat d’un long processus évolutif et de sélections variétales. Parmi ces composés volatils, les monoterpènes comme le géraniol, le citronellol et l’isomenthone, ou les sesquiterpènes comme le 10- γ-épi-eudesmol et le 6,9-guaiadiène, jouent un rôle prépondérant dans le parfum du Pelargonium. Les proportions relatives de ces différents composés sont d’ailleurs utilisées comme marqueurs de la qualité de l’HE et déterminent la typicité du parfum des différents cultivars et origines (P. cv. ‘rosat Bourbon’, P. cv. ‘rosat Chine’, P. cv. ‘rosat Égypte’ et P. cv. ‘rosat Grasse’). Malgré de très nombreux travaux portant sur la chimie de cette HE, il n’existe aucune information sur les voies de biosynthèse de ces molécules et aucun gène intervenant dans ces voies n’a été isolé. Durant cette thèse, nous avons cloné et caractérisé fonctionnellement par expression et purification des protéines recombinantes chez Escherichia coli des gènes codant les enzymes clés de ces voies de biosynthèse, les terpène synthases. Nous avons ainsi pu caractériser quatre terpène synthases, dont une géraniol synthase mono-produit. Nous avons isolé deux autres monoterpène synthases multi-produits, produisant pour l’une majoritairement du myrcène mais aussi trois autres monoterpènes, et pour l’autre majoritairement du 1,8-cinéole ainsi que 10 autres monoterpènes minoritaires. Enfin, une sesquiterpène multi-produit, la 10-γ-épi-eudesmol synthase, a été caractérisée. Nous avons ensuite analysé l’expression de la géraniol synthase et de la 10-γ-épi-eudesmol synthase dans différentes accessions de Pelargonium par RT-qPCR et nous avons montré la relation entre la capacité de production des différents composés volatils et le niveau d’expression dans les feuilles de ces deux terpène synthases. L’efficacité de la transformation génétique du Pelargonium par Agrobacterium tumefaciens étant élevée, des expériences de transgénèse ont aussi été réalisées afin de compléter la caractérisation fonctionnelle des gènes isolés. Dans une deuxième partie, nous avons réalisé l’analyse des essences produites par 64 espèces et cultivars de Pelargonium d’odeurs très diverses (citron, menthe, rose, abricot, pin, épices…). A l’aide d’analyses statistiques (ACP, analyse discriminante…), nous avons mis en évidence des relations entre la biochimie de ces cultivars, leurs odeurs et leurs proximités génétiques et cela afin de nous donner des pistes sur des croisements potentiellement intéressants. Enfin, un dernier chapitre est consacré à l’amélioration de la production d’HE en Égypte. Grâce à ce programme commencé il y a trois ans, nous améliorons chaque année la qualité et le rendement en HE de plus de 10 Ha de plantation de Pelargonium en Égypte. Un travail d’optimisation de la distillation ainsi que des améliorations des pratiques culturales, nous ont permis de produire une HE de qualité avec un rendement de plus de 60 kg.Ha-1 d’HE. D’autres expériences présentées dans ce chapitre soulignent l’influence de l’environnement et notamment de la température sur le ratio entre le citronellol et le géraniol ainsi que sur la biosynthèse de l’isomenthone, du 10-γ-épi-eudesmol et du 6,9-guaiadiène / Pelargonium sp, also named rose scented « geranium » or « Geranium rosat » is one of the the most cultivated aromatic and medicinal plant worldwide, especially for its essential oil (EO), which is used by cosmetic and perfumery industries. This essence is extracted from leaves by steam distillation and gives an EO containing several hundreds of organic volatile compounds (VOC). This complexity is the result of a long evolutive process and varietal selections. Among these VOC, the monoterpenes like geraniol, citronellol and isomenthone and the sesquiterpenes like 10-γ-epieudesmol and 6,9-guaiadiene, play an important role for the Pelargonium fragrance. The relative proportions of these compounds are used as EO quality markers and determine the different cultivars origins (P. cv. ‘rosat Bourbon’, P. cv. ‘rosat Chine’, P. cv. ‘rosat Egypt’ and P. cv. ‘rosat Grasse’). Despite the important researches on the chemistry of these EO, there is no information on the biosynthesis pathways for these molecules and no genes involved in the pathways have been isolated. During this PhD thesis, we have functionally characterized by recombinant proteins expression and purification in Escherichia coli, four genes, three monoterpene and one sesquiterpene synthases, coding for key enzymes in terpene biosynthesis pathway. The first enzyme is a mono-product geraniol synthase. The second enzyme is a multi-product enzyme with a major peak of myrcene and 3 minor peaks of other monoterpenes. The third enzymes is also a multi-product protein, producing 1,8-cineol as major product and 10 others monoterpenes. The last one is a multi-products sesquiterpene synthase producing mainly the 10-γ-epi-eudesmol and other sesquiterpenes. We have also analyzed the level of expression of the geraniol and 10 γ-epi-eudesmol synthases in several Pelargonium accessions by RT-qPCR and we have demonstrated the relationship between the level of expression of these two terpene synthases and the quantity of the related terpenes produced in leaves. Pelargonium transformation efficiency by Agrobacterium tumefaciens was tested in order to complete the functional characterization of the genes. In a second part, we have analyzed the essence of 64 species and cutivars of Pelargonium having very different fragrances like lemon, mint, rose, apricot, pine, spices… With different statistical tools (PCA, discriminant analysis…), we have highlighted the links between the biochemistry of these species and cultivars, their odors and their phylogenetic relationships. This worked gave us some interesting ideas for some new crossings. Finally, the last chapter concerns the EO production improvements in Egypt. Thanks to these researches, started 3 years ago, we are improving year after year our EO yield and quality in our 10 Ha R&D plantation. An important work was done to optimize the distillation process and improve the agricultural practices which abled us to reach a yield of 60 kg of EO per hectare. Some other experiments show the effect of the environmental factors such as the temperature on the biosynthesis of several important molecules like citronellol and geraniol, 6,9-guaiadiene and 10-γ-epi-eudesmol