Dissertations / Theses on the topic 'Plantes en voie de disparition'
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Novi, Kristanti Alfinda. "Etude phytochimique de plantes menacées de disparition." Mulhouse, 1997. http://www.theses.fr/1997MULH0482.
Full textBEIS, STAMATIOS. "Le parler aroumain de metsovo description d'une langue en voie de disparition." Paris 5, 2000. http://www.theses.fr/2000PA05H029.
Full textKatsoyannou, Marianne. "Le parler gréco de Gallicianò (Italie) : description d'une langue en voie de disparition." Paris 7, 1995. http://www.theses.fr/1995PA070123.
Full textGreko, a dying language, is a modern Greek dialect, currently spoken in south of Italy (region of Calabria). As Greko speakers are all bilingual, the grammatical description of the dialect involves the sociolinguistic study of the community. Classified as a meridional modern Greek dialect, Greko presents certain particularities : geminate consonants, simplifications in the system of cases, reduction of aspectual oppositions, development of periphrastic verbal constructions. . . In most cases, these particularities should be studied in relation to Calabrese, the romance dialect spoken in Calabria. The comparative approach brings forth the interaction between Greko and Calabrese, as well as the areal character of certain grammatical trends
Vaillant, Adrien Alp. "Une langue en voie de disparition : le salar au sein de la turcophonie." Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCF019.
Full textSalar is a Turkish dialect most speakers of which live in the county of Xunhua (35°05 north, 102°03 east) in the south-eastern part of the Chinese province of Qinghai where they have been present since the end of the fourteenth century. In spite of the fact that there has been lately an increase in the studies concerning this language, it is still a poor relative of turkology. Carried out with the aim of making it better known, with the support of the available documentation and data collected by the author in his investigation in the field, this thesis offers not only a phonological, grammatical and lexical description of Salar, but also, to the best of the author’s knowledge, for the first time, a detailed study of its nearly extinct traditional writing system that constitutes an adaptation of the Arabic alphabet. We have been particularly careful to take into account the links uniting Salar with other dialects, present and ancient, which form the Turkish domain (particularly with the Oghuz group to which this variety seems to belong) notably through the comparison with Turkey Turkish, based on the translations into the latter of the grammatical items dealt with. Classified as an endangered language by UNESCO, Salar is going through a critical period. The problems raised by its status in China, the position it occupies in the society where it is spoken and the representations to which it is subjected, have also been addressed in this work. A section has been devoted to the identification of a diglossic language situation in the context of which, among the concerns raised by some Salars about the future of their language, lies a project aiming at its revitalisation
Grégoire, Delphine. "Recherches sur les évolutions de la police administrative : une notion en voie de disparition." Bordeaux 4, 2006. http://www.theses.fr/2006BOR40003.
Full textTriki-Teurtroy, Sarah. "Répartition et biologie de la reproduction d'un oeillet en voie de disparition, Dianthus Gratianopolitanus Vill." Paris 11, 2006. http://www.theses.fr/2006PA112327.
Full textLand use often provokes the fragmentation and the reduction in population size of concerned species, consequences which may have major negative effects on genetics, demography or reproduction and therefore on species survival. Dianthus gratianopolitanus Vill. (Caryophyllaceae) is a carnation endemic to Europe. This species has small and scattered populations, growing mainly on calcareous grasslands. This habitat is strongly threatened and has dramatically decreased during the twentieth century. Despite a current distribution that may correspond to that of a glacial relict and a strong fragmentation, genetic differentiation between populations is small, which may indicate a relatively recent fragmentation. Furthermore, genetic diversity is higher than expected for a species with such a fragmented distribution of small populations or in comparison with D. Sylvestris Wulf, which occurs in similar habitat but is far more common. These results may be attributable to the clonal abilities of D. Gratianopolitanus, as observed in Maianthenum bifolium (L. ) Schmidt. Therefore, extinction risk is probably less due to a loss of genetic diversity, even if the probable high selfing rates (revealed by heterozygote deficits) may lead to loss of genetic variation important for adaptability in the long run. Nevertheless, the large population (more than 200 tufts, located at the Chasseron, Switzerland) suffers from pollen limitation, a probable recruitment limitation and a possible genetic load. To confirm this last point, crossings between individuals from different populations are needed
Melser, Su. "Implication du Glucosylceramide dans la voie sécretoire des plantes." Thesis, Bordeaux 2, 2009. http://www.theses.fr/2009BOR21637/document.
Full textThe role of lipids as molecular actors in protein secretion is not well understood in plants. Glucosylceramide (GlcCer) is synthesized by Glucosylceramide Synthase (GCS) in plants and constitutes a key complex sphingolipid in membranes, but little is known about the plant cellular requirements for GlcCer. This study relied upon the block of GlcCer biosynthesis, by the use of inhibitors in tobacco and Arabidopsis, and the production of Arabidopsis mutants, to determine the impact of GlcCer biosynthesis on plant cell endomembrane dynamics. In a comprehensive approach that included lipid biochemistry, live cell imaging, ultrastructural studies by Transmission Electron Microscopy, and whole plant developmental studies, we have gained a better understanding of the impact of GlcCer in plant cells that can be summarised as follows: (1) Based on theoretical analysis and live-cell microscopy the GCS is located to the Endoplasmic Reticulum (at the beginning of the secretory pathway) in plant cells, (2) PDMP is a specific inhibitor of GCS in plants, (3) Disruption of GlcCer biosynthesis using PDMP and genetic approaches showed that GlcCer is important for normal protein trafficking and endomembrane dynamics, notably in the maintenance of Golgi structure, (4) The regulation of protein trafficking by the synthesis of GlcCer could be critical in the establishment and maintenance of cell polarity, as suggested by defects in the localisation of polar markers in Arabidopsis treated with PDMP, and (5) A block in GlcCer synthesis may be conducive to severe defects in plant development, as Arabidopsis mutants showed abnormal primary root growth and inability to develop to reproductive stages. Potential interactions between GlcCer and the transport machineries are discussed, as well as cellular mechanisms that may be set off following a disruption of GlcCer biosynthesis in plant cells
Nenez, Nathalie. "Evolution de l'importance de certaines plantes médicinales dans les spécialités médicamenteuses entre 1965 et 1992." Paris 5, 1998. http://www.theses.fr/1998PA05P143.
Full textDanancher, Delphine. "Apports de l'écologie comportementale à la conservation d'un poisson en voie de disparition : l'apron du Rhône (Zingel Asper)." Lyon 1, 2005. http://www.theses.fr/2005LYO10228.
Full textWattelet, Valérie. "Rôle des acide lysophosphatidique acyltransférases dans la voie sécrétoire chez les plantes." Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0333.
Full textIn eukaryotic cells, membrane lipids are essential for compartmentalization and regulation of secretory pathways. According to their physical properties, they are essential to membrane curvature and regulation of endomembrane morphodynamics, organelle morphology, and vesicles. In animal cells, lysophosphatidic acid acyltransferases (LPAAT) are involved in the regulation of endomembrane trafficking, but nothing is known about their role in plants. In Arabidopsis thaliana, five LPAATs were identified. We determined their specific enzymatic activity for lysophosphatidic acid (LPA) to produce phosphatidic acid (PA). I then characterized their subcellular localization in the endomembrane system of the secretory pathway and their potential role in this pathway using genetical (knockout mutants), biochemical (activity inhibitors, lipid analyzes) and imaging (confocal microscopy) approaches. Using the single, double and triple mutant lines for LPAAT genes that I produced, in addition to CI-976 treatment that inhibits LPAAT activity, I showed, after lipid analysis, that phosphatidic (PA) dependent on LPAAT activity is essential for the trafficking of the auxin carrier PIN2 and the aquaporin PIP2,7 to the plasma membrane.This work highlights the importance of lipid regulation in endomembranes and thresholds under which membrane homeostasis can be finely disturbed to the point of causing dysfunction of the secretory pathway
Capron, Arnaud. "Etude de la voie de protéolyse D-box-dépendante chez les plantes." Université Louis Pasteur (Strasbourg) (1971-2008), 2003. http://www.theses.fr/2003STR13191.
Full textMikail, Tamim. "Les privations de liberté individuelle sont-elles en voie de disparition ? : étude comparée entre les droits français, britiannique et syrien." Grenoble, 2010. http://www.theses.fr/2010GREND003.
Full textIn the three systems of criminal procedure French, British and Syrian, we can usually find an insufficiency of guarantees to ensure the protection of individual liberty against the abusive use of deprivation of liberty before judgement. Thus, in France and Great Britain, several laws have been adopted in recent years show a legislative will aggravate the deprivation of liberty. These laws, in a growing sense of severity, extended duration of certain deprivations of liberty, restricted certain guarantees, advantages, exemptions which the person deprived of his liberty could benefit. That, consequently, generates an imbalance between two requirements : safety and individual freedom. Public safety remains always a priority. The deprivation of liberty is always preferable to other means suitable for carry out the same objective. This reality is observed as much at the time of the procedure prior to the establishment of the culpability as after the establishment of that culpability
Seguela, Mathilde. "Etude de la voie de signalisation de la carence en fer chez Arabidopsis thaliana." Montpellier 2, 2007. http://www.theses.fr/2007MON20222.
Full textIron uptake in non-graminaceous plants is achieved in a three step process. First, protons are released from the roots to solubilize ironbefore its reduction by the FRO2 feric reductase and uptake in roots cells by IRT1 transporter. In iron deficient conditions, IRT1 and FRO2 expression is strongly increased in root epidermal cells. The regulation of these two genes is well described, nevertheless, only few molecular components of the iron deficiency pathway has been described to date. In order to isolate new components regulating the root iron uptake machinery, three different approaches were developed. A genetic screen was performed to isolate mutants affected in IRT1 regulation. One mutant was isolated and shown to be allelic to frd3. The mutation in the FRD3 gene, which encodes for a citrate effluxer in xylem, affects iron speciation in xylem and iron remobilization during germination. The potential role of hormones in iron deficiency signal transduction was investigated. Cytokinins repress IRT1 and FRO2 expression irrespective of the iron status and independently of the transcription factor FIT. Rather we provide evidence or a regulation of IRT1 by a “growth” dependent pathway. The last strategy consisted in the IRT1 promoter analysis, in order to identify cis-regulatory elements of the iron deficiency response. A 80pb region was shown to be essential and sufficient for iron deficiency response in roots. This work shed light on new regulation of IRT1 gene expression and provided tools to unravel the molecular mechanisms driving the iron deficiency response
HUSSELSTEIN, TANIA. "Enzymes de la voie de biosynthese des sterols de plantes : clonages d'alleles sauvages et mutants." Université Louis Pasteur (Strasbourg) (1971-2008), 1998. http://www.theses.fr/1998STR13212.
Full textStotz, Marie Brouillard Raymond Goeldner Maurice. "Contribution à la chimie des flavonoïdes élaboration de squelettes flavylium sophistiqués, nouvelle voie d'accès aux flavan-3-ols et aux proanthocyanidines /." Strasbourg : Université Louis Pasteur, 2008. http://eprints-scd-ulp.u-strasbg.fr:8080/00000982.
Full textJardinaud, Marie-Françoise. "Transformation génétique du colza et du mai͏̈s par la voie haploi͏̈de mâle." Toulouse, INPT, 1994. http://www.theses.fr/1994INPT022A.
Full textStotz, Marie. "Contribution à la chimie des flavonoïdes : Elaboration de squelettes flavylium sophistiqués.Nouvelle voie d'accès aux flavan-3-ols et aux proanthocyanidines." Université Louis Pasteur (Strasbourg) (1971-2008), 2008. https://publication-theses.unistra.fr/restreint/theses_doctorat/2008/STOTZ_Marie_2008.pdf.
Full textIn the plant kingdom, flavonoids represent an important family of secondary metabolites. Because of their natural occurrence, these compounds have always been consumed by human beings and nowadays, several studies have shown that a flavonoid-rich diet is beneficial to human health. In order to obtain active flavonoids at a large scale, total synthesis appears today as the right method. In this context, we tried to develop new synthetic strategies for two flavonoid skeletons: the flavylium skeleton and the flavan-3-ol skeleton. Concerning flavylium derivatives, we reactivated and optimized an original synthetic tool that enables the obtention not only of classical flavylium compounds but also of original oligocationic derivatives. Moreover, the affinity of some synthetic flavylium cations with the GABAA receptor was successfully tested. The chiral flavan-3-ol skeleton (monomeric and dimeric) was studied: our approach consisted in a convergent strategy, with the intervention of an original precursor, the flavylium cation
Barrada, Adam. "Découverte de nouveaux composants de la voie de TOR de plantes par une approche de génétique." Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0165.
Full textTarget of rapamycin is a large kinase existing in most eucaryots such as plants and animals. It is at the center of a signaling pathway regulating growth and metabolism in response to environmental changes, which has been the subject of many studies in humans because of its implication in diseases like cancer. However in plants, the exploration of this pathway is less advanced but the development of ATP competitive inhibitors in humans has offered new possibilities for plant research. Indeed, the use of a TOR inhibitor has allowed us to screen an ethyl methansulfonate mutant bank and discover a new target of TOR: YAK1. The latter regulates growth by inhibiting proliferation notably through cyclin-dependant kinase inhibitors. The screen also allowed us to uncover TOR mutations which potentially affect TOR activity and/or affinity to the inhibitor. This offers a new tool for the study of TOR function in plants
Gréard, Camille. "La détection des variants alléliques comme voie d'amélioration génétique des plantes fourragères : exemple de la luzerne." Thesis, Poitiers, 2019. http://www.theses.fr/2019POIT2261.
Full textLucerne (Medicago sativa) is an autotetraploid forage legume, whose breeding could beneficiate from allele mining. This strategy is based on the natural diversity and consists in seeking alleles with a potential effect on the phenotype. The interest of this approach was evaluated by studying five genes of agronomic interest: CAD1 and CCoaOMT (digestibility), CONSTANS-like (forage yield), NHX1 (salt tolerance) and WXP1 (drought tolerance). The diversity of these five genes was evaluated by sequencing 387 genotypes of cultivated accessions and 20 genotypes of wild accessions. The results confirmed a bottleneck during lucerne domestication and selection. CONSTANS-like and WXP1 were very variable whereas CAD1, CCoaOMT and NHX1 contained very few variants. Variants with a potential strong impact on the phenotype were identified in conserved parts of protein sequence within the Faboideae. The impact on phenotype was studied for two mutations of the CONSTANS-like gene: constans-634, causing a premature stop codon and constans-4111, located in a conserved region of the gene. Genotypes carrying one to three doses of the mutations (AAAB, AABB and ABBB) were polycrossed in order to obtain offsprings with every allele combination (AAAA, AAAB, AABB, ABBB and BBBB). KASPar markers were developed to determine the mutation doses in offspring progeny. No homozygous genotype was found for constans-634 in the 1505 offspring progeny. This mutation induced a premature flowering of three days for the genotypes carrying three doses of the mutation. The mutation constans-4111 induced an additive effect on stem height and the homozygous genotypes without the variant where on average 11.8 cm shorter than homozygous genotypes carrying three or four doses of the variant. The application of allele mining strategy in plant schemes of heterozygous autotetraploid species was discussed
Chardin, Camille. "Adaptation des plantes à la disponibilité en azote : la voie de signalisation nitrate dépendante de NLP7." Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLS186.
Full textNitrogen is one of the most important macronutrients for plants. In the soils, nitrogen can be found under different organic and inorganic forms. Plants preferentially use nitrate, which is not always available for plant uptake and assimilation in soils. Recently, it was shown that the NLP7 transcription factor is a master regulator of the primary nitrate response. Its subcellular protein localization is regulated by nitrate: without nitrate, the protein is localised in the cytoplasm whereas after nitrate resupply, a nuclear retention is observed. Molecular mechanisms of this nuclear-cytosolic shuttling and of the nitrate signal transduction from the external medium to the NLP7 protein are still unknown. It has been shown that the NPF6.3 nitrate transporter plays a role in the nitrate signal sensing, which made this protein a transceptor. Our hypothesis was that NPF6.3 is the nitrate sensor upstream of NLP7. To test this hypothesis, we studied by genetic approaches the epistasis link between the two genes. By studying the simple and double mutant’s biomass and sentinel gene regulation in response to nitrate, we observed additive phenotypes. We showed that the nuclear relocation mechanism of NLP7 is still active in the npf6.3 mutant background. All together, these results showed that NLP7 and NPF6.3 are not in the same signalling pathway but there would be an interplay depending on the conditions. On the other hand, only a few regulators of the nitrate response are known. Interestingly the direct target genes of NLP7 are highly enriched for regulatory proteins such as other transcription factors or protein kinases, which places NLP7 at a high hierarchical place in the nitrate signalling pathway. Indeed these direct targets of NLP7 may themselves be involved in signalling cascades downstream of NLP7. In order to identify molecular events downstream of NLP7, we studies two NLP7 direct targets, Mitogen-Activated Protein Kinase Kinase Kinases (MAPKKKs), MAPKKK13 and MAPKKK14. MAPKs are known to act as phosphorylation cascades. Using biochemical approaches in protoplasts, we have shown that MAPKKKK13/14 are able to activate Group C MAPKs via MKK3. In addition we showed in planta that nitrate addition indeed triggered the activation of group C MAPKs and that this activation is dependent on NLP7 and MKK3. Furthermore we obtained first indications that nitrate-dependent developmental traits and the primary nitrate response are partially impaired in the single mutants mapkkk13 and mapkkk14, and the double mutant mpkkk13mpkkk14
Butaud, Jean-François. "Contribution à la connaissance d'un arbre insulaire en voie de disparition, le santal de Polynésie française (Santalarum insulare) : étude écologique, morphologique, génétique et chimique." Polynésie française, 2006. http://www.theses.fr/2006POLF0002.
Full textThe French Polynesian sandalwood (Santalum insulare) is an endangered species. Overexploited for its fragrant heartwood, its reproduction is only realized by vegetative means due to seed predation by rats and extinction of dispersers. Due to the evaluation of insularity and human perturbations impact on its diversity, our work contributes to the strategy of sustainable management. Morphological, genetical and chemical investigations show differentiations linked to island isolation, ecological conditions and exploitation. This diversity imply sandalwood management not only at the evolutionary unit level corresponding to archipelago, but also at the local level of island, region or population. Chemical studies showed that this sandalwood gave a high grade essential oil. Three new sesquiterpenoids including a new backbone named elvirane were isolated and identified in its concrete. Flavonoids leave content and fatty acid composition of seeds were reported for the first time
Bokström, Marianne. "Le ne dit « explétif » est-il en voie de disparition ? : Développement et usage depuis l´ancien franςais jusqu’au franςais contemporain dans des textes essentiellement littéraires." Thesis, Stockholms universitet, Romanska och klassiska institutionen, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-196931.
Full textCondamines, Elisabeth. "Du côté de chez soi, les vacanciers fidèles de la proximité, une espèce en voie de disparition : étude monographique au Trez-Hir, station littorale finistérienne." Versailles-St Quentin en Yvelines, 2006. http://www.theses.fr/2006VERS018S.
Full textFocusing on the statistical definition of the holidays - four nights out of home - and on their representation the most diffused by the media - the remote departure in commercial lodging - makes delicate the observation of certain kind of holidays such as the holidays carried out not far from home. We used, to highlight them, a monographic analysis of a littoral space, articulated with qualitative enquiries near people spending leisure times in this place. More than a disappearance, we observed a transformation of the modes of relation to this space of proximity, so much so that a significant share of them are not any more holidaymakers stricto sensu. That worsens our blindness, the more so, that holidaymakers, even the most orthodox, hesitate to define themselves as such when they carry out this kind of stay. If some of them have difficulties to keep up their old habits and their legitimacy to be on this littoral and urbanizing space, others have invented, agreeing or constrained, new manners of being present there or of passing part of their holidays there
Ben, Ali Doha. "Production de dianthalexine et de protéines b dans des cellules de Dianthus caryophyllus L. élicitées par Phytophthora parasitica Dastur : approche de la voie de synthèse de la phytoalexine." Lyon 1, 1985. http://www.theses.fr/1985LYO11665.
Full textAnne, Sara. "Influence de la nutrition cuprique sur les composantes du rendement du blé dur (Triticum durum) : et étude de la distribution du cuivre radioactif absorbé par voie racinaire." Toulouse, INPT, 1985. http://www.theses.fr/1985INPT007A.
Full textChampion, Antony. "Contrôle de la division cellulaire chez les plantes : identification d'une voie de signalisation de type SIN (Septum Initiation Network)." Paris 11, 2003. http://www.theses.fr/2003PA112035.
Full textThe time course of events shared by Eucaryotes all along the cell cycle, is strictly controlled by mitotic complexes involving the CDK/cyclin proteins. Studies carried out on S. Cerevisiae and S. Pombe enlight the involvement of an additional signalling cascade, the function of which consists in keeping the cytokinesis in concordance with the end of the mitosis. In S. Pombe, the signalling pathway is named SIN for Septum Initiation Network. Led by the analogy shared with yeast, we identified and analyzed the role of many items of the corresponding plant pathway. We identified A. Thaliana and B. Napus homologues of the fission yeast G protein spg1p (AtSGP1, AtSGP2), the kinase cdc7p (AtMAP3Ke1, AtMAP3Ke2, BnMAP3Ke1) and the kinase sid1p (AtMAP4Kα1, AtMAP4Kα2, BnMAP4Kα2). These are the first characterized homologues of a multicellular Eucaryote. Thcy might participate in a signalling module conserved along the evolution between fungi and plants. We demonstrated the existence of physical and functional interactions between both the plant and the s. Pombe SIN elements. AtSGP1/2, BnMAP3Ke1 and BnMAP4Kα2 are capable of complementing the spg1-B8, cdc7-24 and sid1-239 S. Pombe mutants respectively. Furthermore, we displayed anomalies in the cytokinesis process of wild type S. Pombe over-expressing the SIN-related proteins. An analysis of physical interplays between plant elements and those of the fission yeast clearly evidenced and confirmed the existence of a plant SlN-related signalling pathway. Partial complementation of the yeast mutants indicated that plant homologous proteins diverged from their yeast counterparts to some extend. In addition, we showed that the components colocalized within the nucleolus, which suggests a yet unnoticed regulating mechanisms of this pathway. These data, added to the expression patterns of the corresponding plant genes, and to the phenotypes of AtMAP3Ke1 antisense plants, led us to propose the consistent picture of a SIN related signalling pathway, which controls plant cell division
Ravanel, Stéphane. "Biosynthèse de la méthionine chez les plantes supérieures : étude biochimique et moléculaire des enzymes de la voie de transsulfuration." Université Joseph Fourier (Grenoble ; 1971-2015), 1995. http://www.theses.fr/1995GRE10238.
Full textSAID, RAJAA. "Etude par voie fermentaire des glucides du lait et analyse isotopique comparative de glucose et galactose d'animaux et de plantes." Nantes, 1996. http://www.theses.fr/1996NANT2026.
Full textDechaux, Céline. "Modulation de la voie de biosynthèse de la scopolamine chez Datura innoxia Mill : expression du gène h6h d'Hyoscyamus niger dans des racines transgéniques obtenues par transformation via Agrobacterium rhizogènes." Amiens, 2005. http://www.theses.fr/2005AMIE0507.
Full textSavarin, Julie. "Caractérisation de la voie TCTP (TRANSLATIONALLY CONTROLLED TUMOR PROTEIN) chez Arabidopsis thaliana : identification des régulateurs de son accumulation et importance de la voie au cours du développement embryonnaire." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEN001.
Full textTCTP (Translationally Controlled Tumor Protein) is strongly conserved among eukaryotes. It is a vital protein implicated in various major processes, and its absence leads to early embryolethality in many organisms. In plants as in animals, TCTP is a key factor of growth and development. Implicated in apoptosis and DNA repair, TCTP is also an enhancer of cell proliferation, and is a key element of tumorigenesis. Major functions of TCTP are conserved between plants and animals, but upstream factors are not known yet. Using a genetic screen on the model plant Arabidopsis thaliana, the principal goal of this thesis was to discover regulators of TCTP.In parallel, the impact of TCTP knockout on auxin and cytokinin pathways during embryo development was investigated
Deprost, Dorothée. "Etude du rôle de la voie de signalisation de TOR (Target Of Rapamycin) dans le contrôle de la croissance des plantes." Versailles-St Quentin en Yvelines, 2005. http://www.theses.fr/2005VERS0028.
Full textWe have studied the role of the TOR (Target of Rapamycin) protein kinase, which is present in all eucaryots, in the control of plant growth by signals coming from the environment. We have first shown that the RAPTOR protein is needed for embryonic growth in Arabidopsis thaliana. Disruption of the AtTor gene is lethal but plants over-expressing this gene were obtained following T-DNA insertions in the 5' untranslated region of the gene. These Arabidopsis lines displayed an enhanced growth rate in both the vegetative and reproductive parts. Conversely, silencing of the AtTor expression by RNAi resulted in a decreased growth. Moreover, resistance to stresses and inhibition of senescence appear to be direcly linked to AtTor expression. We have also studied the transcriptome variations in response to AtTor over-expression. These results demonstrate the central role of AtTor in regulating plant growth
Saint-Macary, Marie-Emmanuelle. "Biosynthèse de la cystéine et de la méthionine chez le champignon phytopathogène Magnaporthe grisea : Analyse de la méthionine synthase et des enzymes de la voie de transsulfuration." Pau, 2006. http://www.theses.fr/2006PAUU3008.
Full textFilamentous fungi cause devastating diseases of agricultural crops. Recent studies highlighted a need for sulfur amino acids (methionine and cysteine) in the infectious process. To get insight into the physiological significance of sulfur amino acids biosynthesis in the infectious cycle, we have created null mutants of genes involved in the synthesis of homocysteine, cysteine and methionine by a gene deplacement strategy using a plant pathogenic model, Magnaporthe grisea. To this end the genes encoding cystathionine -synthase (CGS1, direct transsulfuration), methionine synthase and the cystathionine -lyase (CGL, reverse transsulfuration) were targeted. While suppression of the methionine synthase gene led to auxotrophy for methionine, mutants for CGS1 showed only strongly delayed growth, and mutants for CGL were prototroph on minimum medium. When tested on plants, only null mutants for methionine synthase were non pathogenic and the infectious cycle was fully restored upon addition of methionine. In the case of the null mutants for CGS1, the delay in development of disease symptoms was postulated to correspond to metabolic adaptation of the pathogen. This hypothesis was tested by analyzing single null mutants for the CGS2 gene, a homologue of CGS1 in M. Grisea, and for the HCS gene encoding homocystéine synthase which is involved in direct sulphydrylation activity for homocysteine built-up. All the single null mutants were prototroph and non pathogenic on plants. The double null mutant targeting CGS1 and CGS2 showed phenotype similar to the single mutant for CGS1. By contrast, the double mutant line for CGS1 and HCS was auxotroph and its growth was complemented by methionine. Altogether these experiments evidenced the role of the direct transsulfuration pathway in the biosynthesis of homocysteine. Biochemical analysis of the mutant for methionine synthase disclosed metabolite reorientations and molecular adaptation to remove toxic accumulated homocysteine. This compound was degraded through the reverse transsulfuration pathway with accumulation of cystathionine as an intermediate. Pleiotropic effects on glutathione, glutamate, serine and arginine pools resulted from the suppression of the methionine synthase gene. Accumulation of homocysteine led to that of adenosylhomocysteine, a potent inhibitor of the S-adenosylmethionine (SAM) dependent methylases. The built-up of SAM, favored by expression of the fungal SAM-methyltransferase gene, in presence of added methionine was a consequence of the growth restoration. Our analysis led to the finding that the reverse transsulfuration pathway is committed to homocysteine degradation when this toxic compound is in excess. Such interpretation was also confirmed through the accumulated cystathionine measured in the null mutant for CGL1 when grown in the presence of methionine. The integrated analysis of the mutants is a way to decipher the flux of sulfur in the growing pathogenic fungi during the infectious cycle
Ouassou, Malika. "Bases évolutives de la diversification des glucosinolates chez les plantes de l'ordre des Brassicales." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS104.
Full textIn nature, plants are faced with a multitude of external attacks, they are constantly led to refine their defenses against these attacks. Plants of the order Brassicales are known by their capacity to synthesize secondary metabolites called glucosinolates, they are natural products rich in sulfur. After hydrolysis by thioglucosidases called myrosinases, they produce several degradation products that are toxic to parasites such as herbivorous insects or pathogens. The order Brassicales includes more than 130 molecules of glucosinolates, which have a common basic structure, but vary by their side chains. The composition of glucosinolates varies within a species, between species and between Brassicales families. The Arabidopsis thaliana species produces around 40 molecules of glucosinolates from three precursors of amino acids, phenylalanine, tryptophan and methionine. These three types of glucosinolates are generated by three linked and partially overlapping biosynthetic pathways. Glucosinolates synthesized from phenylalanine and from tryptophan are common in Brassicales families. On the other hand, the biosynthesis of glucosinolates derived from methionine is an evolutionary innovation in the youngest families of the order, these types of metabolites are found only in Brassicaceae and some Capparaceae. This new path has led to a large expansion of chemical structures of glucosinolates and is particularly important for the defense of cruciferous plants against their natural enemies. What are the genetic and evolutionary bases of such an adaptive innovation ? Based on a combined approach of comparative genomics, the reconstruction of gene phylogenies and selection tests, this thesis addresses these questions. The evolutionary history of glucosinolates shows multiple duplications of genes involved in glucosinolate biosynthesis, often targeted by the positive and indicative selection of neofunctionalizations. Notably, there were two massive waves of positive selection in the recent history of glucosinolate biosynthesis, one after the separation of the common ancestor Brassicaceae, Cleomaceae, and Capparaceae from an ancestor shared with Resedaceae. other at the base of Brassicaceae. These results show that adaptive innovations involving multiple genes can be established over a relatively short period of time and that full genome duplications may not be required for complex changes in secondary metabolism
Debs-Louka, Espérance. "Destruction des micro-organismes par voie thermo-mécanique contrôlée dans des produits solides en morceaux ou en poudre : application aux épices et aromates." La Rochelle, 2000. http://www.theses.fr/2000LAROS049.
Full textMontiel-Jorda, Álvaro. "Influence de la température sur la voie de signalisation des hormones brassinostéroïdes : mécanismes moléculaires et conséquences pour la croissance et le développement des plantes." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS447.
Full textBrassinosteroid (BR) signaling is important for nearly all aspects of plant development, as attested by the extremely dwarf and sterile phenotype of mutants defective in the brassinosteroid receptor BRASINOSTEROID INSENSITIVE 1 (BRI1). In addition, it is a key regulator of plant responses to increase in ambient temperature (thermomorphogenesis) in the above-ground parts of the plant together with auxin signaling and the transcription factor PHYTOCHROME INTERACTING FACTOR 4 (PIF4). However, the roles molecular mechanisms of root thermomorphogenesis remain elusive. In this thesis, I describe in great detail the molecular mechanisms leading to root thermomorphogenesis of plants exposed to elevated ambient temperature from germination. In order for plants to elongate their primary root at 26°C, compared to 21°C, they selectively downregulate BR signaling via the temperature-specific degradation of BRI1. Surprisingly, under our own conditions, auxin signaling is not required for root thermomorphogenesis, suggesting a difference between aerial and root thermomorphogenesis responses. Using a site-directed mutagenesis approach, we are able to pinpoint that the degradation is triggered by a post-translational modification targeting lysines, probably K63 ubiquitination. To find out the E3 ubiquitin ligase involved in the BRI1 temperature-induced degradation we carried out a yeast two hybrid screen using BRI1’s cytoplasmic domain. We obtained three candidate proteins named DENSE AND ERECT PANICLE (DEP) that surprisingly localize to cortical microtubules (cMTs) and arose at the same time as BR signaling, suggesting a functional link. The interaction between DEP1 and BRI1 was confirmed by three different techniques and, consequently dep single mutants are defective in BR percepton. On one hand, they are hyposensitive to the BR-induced reduction in hypocotyl length but on the other hand they are hypersensitive regarding BR-induced agravitropism. This data suggest an interplay between BR signaling, BRI1 subcellular dynamics and cortical microtubules. Future research will shed light on the biological significance of the BRI1-cMTs interaction in general and the BRI1-DEP1 interaction in particular
Darghouth, Farida. "Etude analytique de l'Olea europaea L. Et Globularia alypum L. Et leurs transformations par voie chimique et microbiologique." Aix-Marseille 3, 1999. http://www.theses.fr/1999AIX30002.
Full textPujol, Claire. "Importation de macromolécules dans les mitochondries et chloroplastes d’Arabidopsis thaliana : Etude des séquences de double adressage des aminoacyl-ARNt synthétases et de la voie de synthèse du Gln-ARNtGln." Université Louis Pasteur (Strasbourg) (1971-2008), 2008. https://publication-theses.unistra.fr/public/theses_doctorat/2008/PUJOL_Claire_2008.pdf.
Full textDuring this work, I was interested in the plant mitochondrial aminoacyl-tRNA synthetases, enzyme which catalyze the aminoacylation of the tranfer RNA during the translation. All these enzymes are encoded by the nucleus and then are imported into mitochondria. However, most of them are also chloroplastic. Dual targeting is determinated by an ambiguous signal located in the N-terminal part of these proteins. Thus mutation or deletion have been performed in order to caracterize these target sequences. We also studied the aminoacylation of the tRNAGln in plant mitochondria and chloroplasts. This pathway involves a non-discriminating Glutamyl-tRNA synthetase and the Glu-tRNAGln amidotransferase (AdT). Indeed this enzyme is the first AdT identified in mitochondria
Michel, Marie. "Développement d'une nouvelle stratégie vaccinale bivalente anti-VIH-1 et anti-VHB dans les plantes transgéniques." Paris 5, 2007. http://www.theses.fr/2007PA05D008.
Full textA fusion protein formed by an HIV-1 polyepitope restricted to the HLA*A2. 01 allele combined to HBV HBsAg has been optimized to obtain virus like particles (VLP) production in vitro and in vivo. An expression plasmid of the fusion protein has been used for DNA vaccination of humanized transgenic mice. This immunization induced gamma interferon-producing CD8+ T cells and anti-HIV-1 cytotoxic T lymphocytes as well as anti-VHB antibody production. The new developments in plant biotechnology allowed the production in plant of vaccines against HBV that can be administrated by ingestion. In order to experiment this strategy for HIV-1, the fusion protein gene has been inserted into the genome of Nicotiana tabacum and Arabidopsis thaliana. We were able to show the stable expression of VLP in these plants. Finally, the analysis of the first generation of tobacco-plants obtained by sexual reproduction showed the conservation of the fusion protein gene as well as the VLP production
Mouillon, Jean-Marie. "Étude du métabolisme du folate chez les plantes : caractérisation de la 6-hydroxyméthyl-7,8-dihydroptérine pyrophosphokinase /7,8-dihydroptéroate synthase." Grenoble 1, 2000. http://www.theses.fr/2000GRE10015.
Full textHassoun, Yasmine. "Etude de la régulation de la voie de biosynthèse des phospholipides en réponse au stress d'enveloppe chez Escherichia coli." Thesis, Aix-Marseille, 2020. http://www.theses.fr/2020AIXM0222.
Full textIn E. coli, enzymes located on the inner membrane ensure the synthesis of phospholipids (PL). The lipid membrane is a barrier between the environment and the internal environment, it is subject to various stresses. PL synthesis is subject to fine regulation in response to these environmental variations to maintain membrane homeostasis. The pathway for PL synthesis is well studied, little is known about its transcriptional regulation. Transcriptomic studies of the envelope stress response by sigmaE factors and the CpxAR system have shown that genes for PL synthetic enzymes are regulated by these factors. In addition, it has been shown that the plsB gene, which codes for the first PL synthesis enzyme, is induced by sigE and inhibited by ppGpp. From there, I studied the stress response regulation of the psd gene, which encodes phosphatidylethanolamine, the major PL in E. coli. To begin with, I confirmed that the first promoter of psd was induced by sigE, then I demonstrated that psd had a second promoter induced by CpxR. My second project focused on the characterization of the clsB gene, which codes for cardiolipin synthase II which synthesizes cardiolipin (CL). clsB is in operon with the two genes of unknown function ybhP and ybhN. Usually, operon gene products work in a common pathway, have a related function, or form a single protein complex. It is for this reason that I wanted to determine the role of ybhP and ybhN in the pathway of LC synthesis and / or in the pathway of PL synthesis. The characterization of YbhP and YbhN is in progress
Kane, Isabelle Céline. "La valorisation du prélèvement végétal : un pari écologique et économique pour le monde paysan en milieu sud-soudanien sénégalais." Lyon 3, 2006. https://scd-resnum.univ-lyon3.fr/in/theses/2006_in_kane_ic.pdf.
Full textThe South Sudanese environment is one of the few areas in Senegal still preserved and rich in vegetal resources but also one of the poorest rural areas of the country. Commercial agriculture, which was promoted solely to support and develop these areas, has been accumulating problems. Confronted with these lasting economic setbacks, there is a need to exploit other means of development for the region as well as develop other sectors such as gathering, which is already a major help to the peasants' lifestyle. Therefore this study wishes to analyse the current role of vegetal gathering in the peasants' life's systems and also the developing prospects offered in the South Sudanese area in Senegal. What matters is to show at this point that the rural development is not the monopoly of the commercial agriculture and that these activities rich in economical and environmental potentials have also their interest in the major politics of rural development
Xia, Yang. "Impact of varying NH₄⁺˸NO₃⁻ ratios in nutrient solution on C-isotope composition of leaf- and root-respired CO₂ and putative respiratory substrates in C₃ plants." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS222.
Full textC-isotope composition of leaf- and root-respired CO₂ in the dark and that of putative respiratory substrates including soluble sugars and organic acids (malate and citrate), PEPc activity, as well as leaf gas exchanges were determined on bean (Phaseolus vulgaris L.) and spinach (Spinacia oleracea L.) plants grown in sand with varying ratios of NH₄⁺: NO₃⁻ in supplied N. Leaf-respired CO₂ was ¹³C enriched under NO₃⁻ nutrition and became progressively ¹³C depleted with increasing amount of NH₄⁺ in supplied N, while C-isotope composition of root-respired CO₂ remained unchanged across N-type gradient. We suggested that a higher amount of ¹³C enriched C-pools fixed by PEPc through anaplerotic pathway contributed to respired CO₂ in leaves under NO₃⁻ nutrition. However, a similar effect in roots expected under NH4+ nutrition was masked because of a rather ¹³C depleted C source (respired CO₂) refixation by PEPc. Unexpectedly, the changes in C-isotope composition of individual metabolites and their amounts as well as PEPc activity exhibited different patterns between the two species. Double labelling experiments (¹³C and ¹⁵N) are needed for better understanding the impact of metabolic plasticity of TCA on isotopic gap between malate and citrate and on C-isotope composition of respired CO₂ in different species under varying N-type nutrition
Mancera-Martinez, Eder Alberto. "Fonction de la protéine cellulaire RISP (Reinitiation Supporting Protein) dans la reinitiation de la traduction chez les plantes." Thesis, Strasbourg, 2014. http://www.theses.fr/2014STRAJ084.
Full textMany factors are required to recruit the tRNAi and a 60S ribosomal subunit to the 40S ribosomal subunit preinitiation complex. This recruitment is normally strictly limited during reinitiation of translation if factors recruited during the primary translation event are shed from 40S. However, factor retention can occur during long ORF translation if the CaMV viral factor TAV is present. RISP is a downstream target of TOR and found either within the 43S preinitiation complex, if bound to eIF3, and/or attached to 60S, if phosphorylated by TOR. We show here that RISP interacts with subunit b of eIF2 before phosphorylation. Critically, TOR activation up-regulates phosphorylation of both RISP and eS6 as well as the binding of both factors. Importantly, eS6-deficient plants are less active in TAV-mediated reinitiation and are thus less susceptible to CaMV infection. It is attractive to propose that eS6 phosphorylation contributes to retention and re-use of 60S during 40S scanning
Makarian, Joelle. "Rôle du facteur d’initiation eIF3h dans la réinitiation de la traduction et dans la pathogénèse virale chez les plantes." Thesis, Strasbourg, 2016. http://www.theses.fr/2016STRAJ089.
Full textTranslation of mRNAs that harbor upstream open reading frames (uORFs) within their leader regions operates via a reinitiation mechanism. In plants, reinitiation is up regulated by the target of rapamycin (TOR) signaling via phosphorylation of the subunit h of initiation factor 3 (eIF3). The eif3h-1 mutant expressing the C-terminally truncated eIF3h while maintaining high translation initiation efficiency is not active in reinitiation. Cauliflower mosaic virus (CaMV) pregenomic polycistronic RNA is translated via an exceptional mechanism of reinitiation after long ORF translation under control of CaMV protein TAV, which ensures activation of TOR. To find the link between underlying mechanisms, we examined eIF3h function in cellular and viral context. Here we show that eIF3h, if phosphorylated, has a role in recruitment of eIF3 into actively translating ribosomes that is a prerequisite for formation of reinitiation-competent ribosomal complexes. C-terminal truncation of eIF3h abolished its integration into the eIF3 complex and eIF3 loading on polysomes as manifested by the eIF3 core subunit c. We also show that eIF3h as a putative target of TOR/S6K1 binds S6K1 in vitro. eIF3h phosphorylation is not required for eIF3 complex formation. We demonstrated that eIF3h is essential for TAV to activate reinitiation after long ORF translation. Protoplasts derived from eif3h-1 mutant failed to support TAV function in reinitiation, which is restored only upon overexpression of recombinant eIF3h indifferent to its phosphorylation status. eif3h-1 mutant defective in reinitiation was found resistant to CaMV infection suggesting that eIF3h is critical for virus amplification. In contrast, viruses that evolve translation initiation dependent on either cap or the internal ribosome entry site infect reinitiation deficient mutant. Thus, we conclude that TAV exploits the basic cell reinitiation machinery, particularly TOR and eIF3h, to overcome cellular barriers to reinitiation after long ORF translation
Jacques, Florian. "Rôle des enzymes ALDH10 dans la voie de biosynthèse de la carnitine et la physiologie de la plante chez Arabidopsis." Thesis, Compiègne, 2019. http://www.theses.fr/2019COMP2487.
Full textCarnitine is a non-proteinogenic amino acid present in all living organisms. Its role in theintracellular transport of fatty acids is well characterized in animals. In plants also, carnitine islinked to lipid metabolism, but its precise role remains poorly understood. In animals andyeasts, carnitine is synthetized from trimethyllysine (TML) through 4 enzymatic steps. The identification in plant tissues of TML and γ-butyrobetaine, the direct precursor of carnitine,suggests that its biosynthesis follows the same steps. A bioinformatics research of candidatesidentified the two ALDH10 enzymes as possibly involved in the synthesis of γ-butyrobetaine.The present study deals with the characterization of the AtALDH10s, to elucidate their role incarnitine biosynthesis and plant physiology. Firstly, the two AtALDH10s were characterized in vitro. This study demonstrates their capability to synthetize γ-butyrobetaine, as well as osmoprotectants. Secondly, an Arabidopsis loss-of-function for the two AtALDH10 has beenobtained and characterized. This mutant is more sensitive to salt stress, bears a longer main shoot and more secondary shoots, and smaller siliques containing less seeds. Its viable seeds are enriched in proteins and fatty acids, and the seedling development is faster. These resultssuggest an intervention of AtALDH10s in the resistance to osmotic stress, the control of plant architecture and the early development. The γ-butyrobetaine content is reduced in the mutant, confirming the involvement of AtALDH10s in the synthesis of γ-butyrobetaine in planta. The residual content of γ-butyrobetaine seems to be sufficient to maintain an unchanged level of carnitine in the mutant. These results raise the question of the regulation of the carnitine biosynthesis pathway and suggest that γ-butyrobetaine could be involved in response to osmotic stress, signalisation pathways and plant architecture. Besides this work, a bioinformatic research lead to the identification of a protein with a structure close to that of the enzyme involved in the conversion of γ-butyrobetaine into carnitine in humans. However, the characterization of this protein did not confirm its involvement in carnitine biosynthesis. The identification and characterization of mutants impaired in enzymatic activities linked to carnitine, such as its biosynthesis or its intervention in the transport of fatty acids, would be valuable to pave the way of a better understanding of the role of carnitine in plants
Guirimand, Grégory. "Organisation cellulaire et subcellulaire de la voie de biosynthèse des alcaloïdes indoliques monoterpéniques de Catharantus roseus." Thesis, Tours, 2011. http://www.theses.fr/2011TOUR4014/document.
Full textCatharanthus roseus is a tropical plant from the Apocynaceae family with a great therapeutic value due to its ability to synthesize monoterpene indole alkaloids (MIA) used in cancer treatment. The yields of these molecules in planta are very low due to a very high level of compartmentation of the biosynthetic pathway at both cellular and subcellular levels. While the cellular compartmentation was widely characterized, very few in situ subcellular localization data were available at the beginning of this PhD. An accurate knowledge of this compartmentation is necessary to identify intermediate metabolites transport events from one compartment to another one, in order to increase the MIA biosynthesis yield by metabolic engineering approaches. In this context we have proceed to the exhaustive study of the subcellular localization of these enzymes by in vivo GFP imaging in C. roseus cells transformed by biolistic. Potential interprotein interactions of these enzymes have also been studied by BiFC. Altogether, our results enabled us to draw an integrated model of the cellular and subcellular organization of MIA biosynthesis in situ
Rondet, Damien. "Caractérisation d'une nouvelle voie de signalisation impliquée dans la défense stomatique et applications agronomiques." Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0083.
Full textPre-invasive or stomatal defense is a mechanism which consists of closing the stomata present at surface of aerial organs of plants when they are in contact with certain pathogens. This closure prevents them from entering and colonizing the host. This mechanism is activated in Arabidopsis inoculated by the bacterium Pseudomonas syringae pv tomato (Pst) DC3000. Preliminary work by our group had shown that carbonylation of target proteins by reactive electrophile species (RES) was a crucial step of the cell signaling required to set up this defense. Through targeted tagging and purifications approaches coupled with tandem mass spectrometry identifications (nanoLC-MS/MS), we have been able to characterize a serine-threonine protein kinase that plays a crucial role in this defense mechanism. Indeed, plants mutated on the gene encoding this protein have lost their ability to trigger stomatal closure and to deploy the stomatal defense against the bacteria. In addition, the use of the click chemistry and notably, the copper-catalyzed alkyne-azide cycloaddition, in our tagging approaches has enabled us to identify a set of proteins that are most likely carbonylated and likely to play a significant role in these cell events that contribute to part of plant immunity. Finally, since RES are able to induce stomatal closure we sought to find out, in the context of establishing a proof-of-concept, whether their application to plants would enable them to be protected against the Pst
Vialart, Guilhem. "Identification et caractérisation fonctionnelle de gènes impliqués dans la voie de biosynthèse des furocoumarines chez les végétaux supérieurs." Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0390/document.
Full textFuranocoumarins are secondary metabolites deriving from the phenylpropanoid biosynthetic pathway. These phytoalexins are especially involved in plant defense mechanisms against insects or phytopatogenous fungi and bacteria. The molecular control of this biosynthetic pathway is still poorly understood even though it has been demonstrated since the 1960s that enzymes catalyzing the different steps are belonging to different enzymatic families. The work presented here is focused on two enzyme families: oxoglutarate dependent dioxygenases and cytochrome P450s. The first step in the furanocoumarins biosynthetic pathway is the ortho-hydroxylation of p-coumarate, which leads to the formation of umbelliferone. Based on a recent work done on Arabidopsis, we isolated six genes encoding dioxygenases from Ruta graveolens, Citrus limetta and Pastinaca sativa. The corresponding proteins share more than 58% identity with the A. thaliana féruloyle 6' Hydroxylase (F6'H). The functional characterization of these enzymes was performed in a prokaryotic heterologous expression system. Of the six enzymes, three could not be functionnaly expressed and two exhibited a similar F6'H activity as described for A. thaliana. The last enzyme has new properties not described to date. It is able to achieve both hydroxylation of féruloyle CoA and p-coumaroyle CoA. These in vitro studies were completed by a functional exploration of the protein in planta. A detailed analysis of the gene expression pattern highlighted a link with the level of umbelliferone synthesis. The function of the protein was also confirmed by an analysis of the products formed in transiently transformed Nicotiana benthamiana leaves. Cytochrome P450s catalyze 60% of the reactions of the furanocoumarin biosynthetic pathway. Therefore, a functional screening of cytochrome P450 previously identified in Ammi majus and Thapsia garganica was undertaken. The bioinformatic analyses and the changes undertaken in the procedure for expression in yeast allowed drawing hypotheses on the function of some of these P450 candidates. These exploratory and preliminary experiments allowed suggesting new hypotheses about the biosynthetic pathway
Ginis, Olivia. "Identification de facteurs de transcription régulateurs de la voie de biosynthèse des alcaloïdes indoliques monoterpéniques chez Catharanthus roseus." Thesis, Tours, 2012. http://www.theses.fr/2012TOUR4014/document.
Full textCatharanthus roseus is a tropical plant producing specifically monoterpene indole alkaloids (MIA) of high interest due to their therapeutical values. In C. roseus cells, the terpenoid branch including the methyl erythritol phosphate pathway (MEP) provides the MIA terpenoid moiety and is regarded as limited for MIA biosynthesis. This branch presents a coordinated transcriptional regulation in response to hormonal signals leading to MIA production. In this context, bioinformatic analysises and functional characterization of MEP pathway gene promoters allowed the identification of new transcription factor families involved in the MIA pathway regulation. Members of ZCT proteins, WRKY and type B RR families specifically interact with the hds promoter from the MEP pathway and regulate its activity. This work permits to gain into insight the transcriptional network controlling the MIA biosynthesis. It is possible now to consider using transcription factor that act as activators and target genes from the terpenoid branch to increase the accumulation of alkaloids of pharmaceutical interest in C. roseus by metabolic engineering approaches
Gakière, Bertrand. "Dérégulation de la biosynthèse de la méthionine chez les plantes supérieures : analyses phénotypiques, moléculaires et biochimiques de plants d'Arabidopsis thaliana exprimant des ARN antisens ou sens de la cystathionine [gamma]-synthase ou de la cystathionine [bêta]-lyase." Université Joseph Fourier (Grenoble), 1999. http://www.theses.fr/1999GRE10058.
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