Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2017-04-26T14:05:04Z No. of bitstreams: 1 2012 - Patricia Gon?alves Galv?o.pdf: 5289496 bytes, checksum: 8dcb41bc971793cc8b4cdf383401ade4 (MD5) / Made available in DSpace on 2017-04-26T14:05:05Z (GMT). No. of bitstreams: 1 2012 - Patricia Gon?alves Galv?o.pdf: 5289496 bytes, checksum: 8dcb41bc971793cc8b4cdf383401ade4 (MD5) Previous issue date: 2012-03-01 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / The objective of this study was to evaluate the protein profile expression of G. diazotrophicus PAL5 and its defective mutant in the indole compound production (lao-) grown in the presence or absence of tryptophan through 2DE-PAGE technique. The spectrometric analysis allowed the identification of 24 differentially expressed proteins. The majority of the proteins down regulated in the wild type PAL5 cultivated with tryptophan as compared to the cultivation without the amino acid belonged to the category of transductional modification, protein turnover and chaperones. For the mutant lao- grown in the same conditions, the majority of the proteins that presented differential expression belonged to the category of production and conversion of energy. In addition, the majority of the protein differentially expressed in the mutant lao- as compared to the wild-type PAL5 strains belonged to carbohydrates metabolism and transport. On the other hand, no proteins related to the tryptophan biosynthesis were detected in any condition, possibly due to the low yield of the proteins during the spectrometric analysis. Furthermore, mutants lao- and nif- of G. diazotrophicus were used for inoculation of micropropagated sugarcane plants in order to determine the influence of auxins produced by the bacteria in the plant growth promotion in comparison with PAL5. The first experiment, carried out in hydroponic conditions for 10 days showed a significant inoculation effect of the wild type on plant shoot. The other experiment was conducted in a period of 120 days in pots containing sand:vermiculite substrate fertilized with 30 and 60 ppm with ammonium sulphate enriched with 15N. The plants were inoculated in vitro with the wild type and mutants lao- and nif-, and the results showed a visual difference in the roots inoculated with PAL5 that showed higher volume suggesting a higher number of secondary roots and root hairs. On the other hand, the plants inoculated with the lao- mutant were ticker and showed lower number of secondary roots and root hairs. The shoot biomass of plants inoculated with PAL5 was higher than those inoculated with the mutant strains for both N dose, however the difference was not significant. Plants grown with 60 kg N dose and inoculated with the mutants showed lower accumulation of dry shoot mass than plants inoculated with the wild type strain. In conclusion, the present study showed the occurrence of several differentially expressed proteins either in the wild type strain or in the mutant lao- grown in LGI-P with and without tryptophan. The role played by these proteins in the metabolism of the bacteria requires additional studies, including different growth conditions. In addition, the inoculation of micropropagated sugarcane plants suggested a hormonal effect of the bacteria mainly on the root development e consequently in the N use efficiency. However, the size of the pots may have limited the plant development, suggesting that new experiments should be carried out in more appropriated conditions to confirm the influence of the indol production and the BNF during the association of the G. diazotrophicus and sugarcane plants / Este estudo teve por objetivo avaliar o perfil de express?o de prote?nas de G. diazotrophicus PAL5 e seu mutante defectivo na produ??o de compostos ind?licos (lao-) cultivados na presen?a e aus?ncia de triptofano atrav?s da t?cnica de 2DE-PAGE. A an?lise por espectrometria de massa permitiu a identifica??o de 24 prote?nas diferencialmente expressas. A maioria das prote?nas com a express?o diminu?da em PAL5 cultivada em meio com triptofano em rela??o ao meio de cultivo sem esse amino?cido pertenceu ? categoria modifica??o p?s-traducional, turnover de prote?nas e chaperonas. No mutante lao- cultivado nas mesmas condi??es, a maioria das prote?nas que apresentaram express?o diferencial pertencia ? categoria produ??o e convers?o de energia. Em adi??o, a maioria das prote?nas que foram diferencialmente expressas no mutante lao- em compara??o com a estirpe selvagem PAL5 pertencia ? categoria metabolismo e transporte de carboidratos. Por outro lado, n?o foram observadas prote?nas relacionadas ? bioss?ntese de triptofano em nenhuma condi??o analisada possivelmente devido ao baixo rendimento das identifica??es por espectrometria. Al?m das an?lises dos perfis de prote?nas, os mutantes lao- e nif- de G. diazotrophicus foram inoculados em plantas de cana-de-a??car micropropagadas com o objetivo de determinar a influ?ncia das auxinas na promo??o do crescimento dessa cultura em compara??o com a estirpe selvagem PAL5. O primeiro experimento, conduzido em condi??es de hidroponia pelo per?odo de 10 dias, mostrou efeito significativo da inocula??o da estirpe selvagem na promo??o de crescimento da parte ?rea das plantas, enquanto que o mutante lao-, n?o diferiu estatisticamente do controle n?o inoculado. O outro experimento, foi conduzido por 120 dias em vasos com substrato areia:vermiculita contendo 30 ou 60 ppm de sulfato de am?nio enriquecido com 15N e as pl?ntulas foram inoculadas in vitro. Os resultados mostraram uma diferen?a visual nas ra?zes das plantas inoculadas com PAL5, que se mostraram mais volumosas, aparentando um n?mero mais elevado de ra?zes secund?rias e p?los radiculares. J? as plantas inoculadas com lao- apresentaram ra?zes mais grossas, com um n?mero muito reduzido de ramifica??es ou p?los radiculares. A biomassa seca da parte a?rea das plantas inoculadas com PAL5 foi superior ?quelas inoculadas com as estirpes mutantes para as duas doses de nitrog?nio, por?m essa diferen?a n?o foi significativa. N?o foram observadas evid?ncias de contribui??o da FBN, por?m as plantas inoculadas com PAL5 foram menos eficientes na recupera??o do N fertilizante. Em conclus?o, o presente estudo mostra a ocorr?ncia de diversas prote?nas diferencialmente expressas tanto na estirpe selvagem como em lao- quando crescidas na presen?a e aus?ncia do amino?cido triptofano. A defini??o do papel dessas prote?nas no metabolismo da bact?ria requer estudos adicionais, inclusive em diferentes condi??es de cultivo. Em adi??o, a inocula??o dessas bact?rias em plantas de cana-de-a??car mostrou o efeito hormonal da bact?ria no desenvolvimento das ra?zes e, por conseguinte na maior efici?ncia de uso do N aplicado. Entretanto, dado a limita??o de espa?o f?sico dos vasos para o desenvolvimento das plantas, sugere-se a realiza??o de novos experimentos, em condi??es mais apropriadas, para confirmar a influ?ncia da produ??o de ?ndoles e da FBN durante a associa??o da bact?ria com as plantas de cana-de-a??car.

Naminė obelis (Malus x domestica Borkh.) yra vienas plačiausiai auginamų ir ekonomiškai svarbių vaismedžių. Obels vainiko architektūra yra biologinis požymis, nuo kurio priklauso vaismedžio derėjimo tipas, sąnaudų genėjimui poreikis. Obels vainiko architektūros tyrimai apima augimo reguliatorių taikymo, šakų vystymosi, genėjimo, aplinkos veiksnių poveikio augalų vainiko architektūrai tyrimus. Genetiniai ir fiziologiniai aspektai kol kas mažai ištirti. Tyrimų tikslas – ištirti obels vainiko architektūros paveldėjimą, nustatyti morfologinius ir molekulinius žymenis, susietus su obels vainiko forma ir numatyti jų panaudojimą juvenaliniame raidos tarpsnyje prognozuojant obels hibridų vainiko formą. Pirmą kartą nustatyti koloninės ir svyrančios vainiko formos obelų morfologiniai ir biocheminiai žymenys juvenaliniame raidos tarpsnyje. Šių žymenų naudojimas leidžia atrinkti norimos vainiko formos hibridus pirmais auginimo metais. Nustatyti obels morfologinių požymių, tiesiogiai susietų su vainiko architektūra, paveldėjimo dėsningumai. Ištirta, kad kryžminimuose naudotų koloninių veislių Co genas yra heterozigotinėje būsenoje. Pirmą kartą ištirta augalo hormonų dinamika skirtingos vainiko formos obelų lapuose vegetacijos laikotarpiu. Atskleistas abscizo ir giberelo rūgščių antagonistinis ryšys bei sinergetinis ryšys tarp giberelo rūgšties ir zeatino kontroliuojant obelų tarpubamblio ilgį. Pirmą kartą nustatyti biocheminiai žymenys, tinkami hibridų koloninei vainiko formai... [toliau žr. visą tekstą] / Apple (Malus x domestica Borkh.) is one of the most widespread and economically important fruit trees. Canopy architecture of an apple determines fruit bearing and demand for pruning. Main apple canopy architecture topics are related to application of growth regulators, fertilizers, studies of shoot development and pruning, and environmental influence. Genetic and physiologic aspects are studied less. The aim of the research was to investigate inheritance of apple tree canopy architecture, to identify morphological and molecular markers related to canopy architecture and to evaluate their usage in predicting canopy ideotype of apple seedlings in juvenile phase. Morphological and biochemical markers for selection of columnar and weeping apple seedlings were identified for the first time. Usage of these markers enables to select hybrids with desired canopy form during first year of growing. Regularities of morphological trait inheritance were established. It was established, that Co gene is dominant heterozygous in parental columnar clones. Dynamics of phytohormones in leafs of apple trees with different canopy architecture during vegetation were evaluated for the first time. Antagonistic relation between abscisic and giberelic acids and synergetic link between giberelic acid and zeatin controlling apple internode length was identified. Biochemical markers for identifying columnar seedling canopy in juvenile phase were established for the first time. High amount of auxin and... [to full text]

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Made available in DSpace on 2015-04-20T12:22:45Z (GMT). No. of bitstreams: 1 Tese Sonia.pdf: 1055370 bytes, checksum: 3e991b5884a4ccba6d3975a926b8a86a (MD5) Previous issue date: 2011-10-31 / Fundação de Amparo à Pesquisa do Estado do Amazonas / Although guarana (Paullinia cupana var. Sorbilis (Mart.) Ducke) is a culture of great interest to the Amazon region, its productivity is still low. The availability of plant material that is genetically uniform, precocious and productive is the key for expanding and improving the culture in the region. To achieve this, it is recommended to do vegetative propagation, although some cultivars have rooting problems. This study aimed to evaluate the rooting of guarana from fertilized and unfertilized plants submitted to increasing levels of irradiance, with and without application of IBA. It also aimed to correlate the reserves of the branches and cuttings with rooting characteristics. The design was completely randomized in factorial arrangement of 6x4x2x2. The factors studied were the following: (i) five cultivars and one genotype of guarana, (ii) four levels of irradiance, (iii) with and without fertilization and (iv) application of IBA or not. The experimental unit contained 10 cuttings with four repetitions. The mother plants received or did not received fertilizer in the field for ten years and were subjected to increasing levels of irradiance for 60 days. The cuttings were taken from these plants and remained in the nursery for 120 days for rooting. After this period we evaluated the number of rooted cuttings with calluses and dead, root number, volume, length and dry weight of roots. The carbohydrate content was determined from the branches and rooted cuttings at the time of the dismantling of the research. The rooting of cuttings was higher for the fertilization treatment for BRS-Maues, CMU-CG 381 and BRS 882. The reduction of irradiance on the mother plant favored rooting. The highest percentage of rooting and lower mortality were obtained from cuttings without IBA treatment, independently of cultivar. The cv. BRS-Maués showed the highest rooting potential, while BRS-CG882 had the lowest rooting. BRS-Maués was more efficient in accumulating starch than the BRS- 882 CG and the rooting potential of both cultivars was positively correlated with the starch accumulated in each one. Regarding the total soluble sugars in the branches, there was no correlation for BRS-882 CG. For BRS-Maués the correlation was negative in relation to rooting of these twocultivars. / guaranazeiro (Paullinia cupana var. sorbilis (Mart.) Ducke) é uma cultura de grande interesse para a região Amazônica, mas sua produtividade é ainda baixa. A disponibilidade de material vegetal geneticamente uniforme, precoce e produtivo é fundamental para a expansão e melhoria da cultura na região. Para isso, recomenda-se a propagação vegetativa, no entanto algumas cultivares apresentam problemas de enraizamento. Esse trabalho teve como objetivo avaliar o enraizamento de estacas de guaranazeiro provenientes de plantas adubadas e não adubadas, submetidas à níveis crescentes de irradiância, com e sem aplicação de AIB e, correlacionar as reservas dos ramos e das estacas com as características de enraizamento. O delineamento adotado foi inteiramente casualizado, em arranjo fatorial de 6x4x2x2. Os fatores estudados foram: cinco cultivares e um genótipo de guaranazeiro, quatro níveis de irradiância, presença e ausência de adubação e aplicação ou não de AIB. A unidade experimental continha 10 estacas com 4 repetições. As plantas matrizes receberam ou não adubação, no campo, durante dez anos e foram submetidas a níveis crescentes de irradiância por 60 dias. As estacas foram retiradas dessas plantas e permaneceram em viveiro por 120 dias para enraizamento. Após este período foram avaliados o número de estacas enraizadas, com calos e mortas, número de raiz, volume, comprimento e peso da matéria seca das raízes. Os teores de carboidratos foram determinados nos ramos e nas estacas enraizadas no momento do desmonte da pesquisa. O enraizamento das estacas foi maior no tratamento com adubação para as cultivares BRS-Maués, CMU 381 e BRS-CG 882. A redução da irradiância sobre as plantas matrizes favoreceu o enraizamento. O maior percentual de enraizamento e o menor de mortalidade das estacas foram obtidos no tratamento sem AIB, independente, da cultivar. A cv. BRS-Maués expressou o maior potencial de enraizamento, enquanto BRS-CG882 apresentou o menor enraizamento de estacas. BRS-Maués foi mais eficiente em acumular amido que a BRS-CG 882 e o potencial de enraizamento das duas cultivares apresentou correlação positiva com o teor de amido acumulado em cada uma. Quanto aos açúcares solúveis totais nos ramos, para BRS-CG 882 não houve correlação e para BRS-Maués foi negativa em relação ao enraizamento dessas duas cultivares. Palavras-chave: Propagação vegetativa, estaquia, sombreamento, fitohormônio, carboidratos.

Fortes chuvas e outros eventos climáticos podem afetar o fitness de plantas e insetos. Estudos recentes têm demonstrado que esses organismos são capazes de detectar súbitas variações da pressão barométrica que antecedem a condição climática adversa. Para os insetos, esta percepção é acompanhada de alterações comportamentais aparentemente adaptativas, como a redução do voo e chamamento para cópula. As plantas, por sua vez, respondem com a abertura dos estômatos, de maneira muito semelhante ao estresse hídrico, devido à ativação de rotas bioquímicas associadas ao ácido abscísico. O longo histórico co-evolutivo entre plantas e insetos herbívoros indica que alterações em um organismo reflete na resposta adaptativa do outro. Assim, mesmo que a variação na pressão barométrica afete apenas um dos organismos, a interação inseto-planta deve ser alterada, porém, esta abordagem nunca foi estudada. Utilizando como modelo o milho, Zea mays L. (Poales: Poaceae) e a lagarta-cartucho-do-milho, Spodoptera frugiperda (J.E. Smith, 1797) (Lepidoptera: Noctuidae), nós investigamos o desempenho alimentar do inseto e defesas induzidas de plantas intactas e com indução pela herbivoria frente a diferentes pressões barométricas. Para isso foram desenvolvidos dispositivos automatizados e os ensaios foram conduzidos dentro de uma câmara barométrica. As lagartas consumiram maiores áreas foliares em pressão baixa do que alta, porém o ganho de peso foi similar nas pressões testadas. Plantas intactas, danificadas pela lagarta e com aplicação do regurgito de S. frugiperda não produziram defesas induzidas pela pressão barométrica, apesar dos tratamentos com indução pelo herbívoro emitirem misturas mais complexa de voláteis comparado às plantas intactas. Além disso, plantas com indução mecânica apresentaram maiores níveis do fitohormônio ácido jasmônico. Nesse contexto, nós hipotetizamos que condições de estresse, como pressão baixa, aumentam o consumo foliar e taxa metabólica das lagartas, resultando em incremento de peso similar a condições não estressantes. Em contrapartida, plantas de milho aparentemente não utilizam a pressão como fator abiótico preditor de alterações climáticas e aumento de herbivoria. Para o melhor do nosso conhecimento, este foi o primeiro estudo a investigar os efeitos da pressão barométrica na interação planta-inseto herbívoro e os resultados obtidos podem repercutir na inclusão da pressão como fator que transmuta ensaios biológicos. / Severe raining and other climatic events can affect plant and insect\'s fitness. Recent studies have shown that these organisms are able to detect sudden barometric pressure variations that generally precede an adverse climatic condition. For insects, this perception is followed by behavioral modifications that are apparently adaptive, as, for instance, the reduction in flights and the calling for mating. Plants, in turn, respond with stomata opening, similar to hydric stress, once biochemical routes associated to the abscisic acid are activated. The historical co-evolutive process between plants and herbivore insects indicate that changes in one organism reflects in the adaptive responses of the other. In that sense, even if the fluctuation of the barometric pressure has direct effects in a single organism, the insect-plant interaction may be altered. However, this approach has never been examined. Taking as models maize plants, Zea mays L. (Poales: Poaceae), and the fall armyworm, Spodoptera frugiperda (J.E. Smith, 1797) (Lepidoptera: Noctuidae) we have investigated the feeding performance and induced defences of intact and herbivore-induced plants under different barometric pressures. For that, we developed automated devices and the assays were conducted inside of a barometric chamber. The fall armyworms larvae consumed greater leaf areas under low than high pressures, but the weight gain was similar among the pressures tested. Wound-induced maize did not displayed defenses by the barometric pressure changes, although the treatments with herbivore induction have emitted more complex volatiles blends when compared to intact maize. Besides that, plants with mechanical damage presented higher levels of the phytohormone jasmonic acid. In this context, we have hypothesized that stress conditions by low pressures increase the leaf area consumption by S. frugiperda, possibly associated to higher metabolic rates of armyworms, resulting in a weight gain similar to the non-stress conditions. On the other hand, corn plants apparently do not use the barometric pressure as an abiotic predictor of climatic changes and increase of herbivory. To the best of our knowlegde this is the first study investigating the barometrtic pressure effects on plant-herbivore insect interaction. Our results may potencially impact in the inclusion of pressure as factor that reshape biological assays.

Abiotic stresses significantly reduce crop yield, causing serious problems in agriculture. Understanding the mechanisms of plant stress responses could contribute to the improvement of their stress tolerance. Phytohormones play an important role in plant stress defence as well as in regulation of growth and development. This thesis summarizes the results published in four articles focused on the evaluation of the effects of phytohormones during abiotic stresses, namely salinity, drought, ZnO nanoparticle treatment and cold stress. The main emphasis is put on abscisic acid as the key regulator of water status and stress defence, and on cytokinins, which regulate plant growth and stabilize photosynthetic machinery. Cytokinins act antagonistically to abscisic acid. Our results showed that abscisic acid is a general abiotic stress response regulator. Stress- tolerant plants (halophyte Thellungiella salsuginea or winter line of einkorn wheat Triticum monococcum) had a higher basal level of this hormone, especially in shoot meristematic tissues (apices, crowns), than stress-sensitive plants. Stress-tolerant plants reacted faster and in a more flexible way to stress. Active cytokinins were negatively affected by stress, which was associated with growth suppression. The drought stress study showed that...

Les jasmonates de méthyle sont des oxylipines asymétriques impliquées dans les mécanismes de défense, de développement et de régulation des organismes photosynthétiques terrestres ou marins face à des stress biotiques et abiotiques. Parmi les quatre stéréoisomères, seuls l’épi-jasmonate et l’ent-épi-jasmonate de méthyle possèdent de bonnes propriétés organoleptiques mais aussi une forte activité phytohormonale permettant l’élicitation de métabolites secondaires bioactifs. En ciblant spécifiquement une hexokinase mitochondriale régulant le métabolisme des cellules cancéreuses, les jasmonates de méthyle constituent d’excellents candidats pour de nouveaux agents thérapeutiques. Dans la recherche constante de nouvelles molécules thérapeutiques issues du milieu naturel, notre laboratoire s’est donc focalisé sur la synthèse énantiosélective de l’épi-jasmonate et l’ent-épi-jasmonate de méthyle, au départ de diols bicycliques homochiraux monoprotégés dérivant du cyclooct-1,5-diène.Afin d’obtenir ces diols bicycliques énantiopurs, une stratégie innovante a consisté en l’étude de la réaction d’électrocyclisation du méso-époxyde dérivé du cyclooct-1,5-diène assistée par des ligands chiraux métallés diversement fonctionnalisés, les catalyseurs de Jacobsen. En mettant à profit notre savoir-faire sur les désymétrisations enzymatiques, une stratégie parallèle optant pour la résolution énantiosélective de diols homochiraux monocycliques, ou de diols bicycliques C2-symétriques nous a permis d’accéder à des silanyloxyindèn-5-ones chirales, précurseurs clé des cis-jasmonates de méthyle énantiopurs. Enfin, la synthèse racémique de deux jasmonoïdes clé, la (±)--jasmolactone, puis le (±)-épi-jasmonate de méthyle a été validée en 15 étapes à partir du cyclooct-1,5-diène. / Methyl jasmonates are asymmetric oxylipins involved in defensive, developmental and regulative mechanisms of terrestrial and marine photosynthetic organisms in response to biotic and abiotic challenges. Among the four stereoisomers, only methyl epi-jasmonate and ent-epi-jasmonate show good organoleptic properties but also phytohormonal activity allowing the elicitation of bioactive secondary metabolites. Because they specifically target a mitochondrial hexokinase regulating the metabolism of cancer cells, methyl jasmonates have become excellent candidates as new therapeutic agents. With a constant attention on new therapeutic agents derived from the natural environment, our laboratory has focused on the enantioselective synthesis of methyl epi-jasmonate and ent-epi-jasmonate using monoprotected homochiral diols derived from cyclooct-1,5-diene.In order to obtain these chiral bicyclic diols, an innovative strategy has involved the study of the chemo-stereoselective electrocyclization of the cyclooct-1,5-diene-derived meso-epoxide assisted by chiral metallated ligands known as Jacobsen’s catalysts. Taking advantage of our knowledge of enzymatic desymmetrization, a second strategy opting for the enantioselective resolution of monocyclic homochiral diols or C2-symmetric bicyclic diols led access to chiral silanyloxyinden-5-ones, key precursors to chiral methyl cis-jasmonates. Meanwhile, the racemic synthesis of (±)--jasmolactone and methyl (±)-epi-jasmonate was validated in 15 steps starting from cyclooct-1,5-diene.

No description available.

Master of Science / Department of Agronomy / P. V. Vara Prasad / In many countries producers have been growing varieties of hard white winter (HWW) wheat since decades. The cause of concern is most varieties of HWW wheat are susceptible to pre-harvest sprouting (PHS) which affects grain quality. Environmental conditions like high humidity, precipitation, heavy dew and hormonal activity at physiological maturity stimulate PHS in HWW. To alleviate these conditions research was carried out at KSU. KS01HW163-4, a sprouting tolerance line was crossed with Heyne, a sprout susceptible cultivar. A total of 224 doubled haploid (DH) lines thus produced were phenotyped in the present study through experiments conducted in controlled environments. The objectives of this research were to (i) characterize and phenotype the doubled haploid lines for PHS in controlled environments; (ii) understand the impact of growth environment (high temperature and/or drought) and; (iii) impact of exogenous application of growth hormones on tolerance to pre-harvest sprouting in the parental lines of the doubled haploid population. The phenotypic data collected from this research will be ultimately combined with the genotypic data to identify DNA markers related to PHS tolerance and provide DNA markers for marker assisted selection. Based on my results of the germination percentages from the 224 DH lines, the population was distributed as susceptible, and tolerant to PHS showing a bimodal distribution and X[superscript]2 analysis indicating a complimentary gene action. From the study of the influence of environmental factors on PHS, my results confirmed a definite influence of stress on sprouting. Under optimum temperature (OT), KS01HS163-4 was tolerant to PHS, but at HT and/or drought it became susceptible to PHS. Growth under stressed conditions changed the tolerance levels to PHS. Seed dry-weight, and harvest index were also influenced negatively due to stress. Therefore multi-location tests must be conducted with variable environments to test the stability of a variety to PHS. From the study of the influence of phytohormones on PHS, the results suggest that tolerance to sprouting was seen in seeds from plants sprayed with abscisic acid (ABA) and paclobutrazol (GA-inhibitor) treatments where as those from gibberellic acid (GA) treatment showed susceptibility to sprouting.

Les jasmonates de méthyle sont des oxylipines asymétriques impliquées dans les mécanismes de défense, de développement et de régulation des organismes photosynthétiques terrestres ou marins face à des stress biotiques et abiotiques. Parmi les quatre stéréoisomères, seuls l'épi-jasmonate et l'ent-épi-jasmonate de méthyle possèdent de bonnes propriétés organoleptiques mais aussi une forte activité phytohormonale permettant l'élicitation de métabolites secondaires bioactifs. En ciblant spécifiquement une hexokinase mitochondriale régulant le métabolisme des cellules cancéreuses, les jasmonates de méthyle constituent d'excellents candidats pour de nouveaux agents thérapeutiques. Dans la recherche constante de nouvelles molécules thérapeutiques issues du milieu naturel, notre laboratoire s'est donc focalisé sur la synthèse énantiosélective de l'épi-jasmonate et l'ent-épi-jasmonate de méthyle, au départ de diols bicycliques homochiraux monoprotégés dérivant du cyclooct-1,5-diène.Afin d'obtenir ces diols bicycliques énantiopurs, une stratégie innovante a consisté en l'étude de la réaction d'électrocyclisation du méso-époxyde dérivé du cyclooct-1,5-diène assistée par des ligands chiraux métallés diversement fonctionnalisés, les catalyseurs de Jacobsen. En mettant à profit notre savoir-faire sur les désymétrisations enzymatiques, une stratégie parallèle optant pour la résolution énantiosélective de diols homochiraux monocycliques, ou de diols bicycliques C2-symétriques nous a permis d'accéder à des silanyloxyindèn-5-ones chirales, précurseurs clé des cis-jasmonates de méthyle énantiopurs. Enfin, la synthèse racémique de deux jasmonoïdes clé, la (±)--jasmolactone, puis le (±)-épi-jasmonate de méthyle a été validée en 15 étapes à partir du cyclooct-1,5-diène.