Le but de notre travail est de développer une stratégie de vectorisation pour conférer la mobilité phloémienne aux produits agrochimiques en appliquant le concept de prodrogue dans l'élaboration de composés phytopharmaceutiques. Le fenpiclonil, fongicide non systémique de la famille des phénylpyrroles, a été choisi comme composé parent modèle et modifié en l'associant à un acide alpha-aminé ou à un monosaccharide.La mobilité phloémienne des conjugués entre le fenpiclonil et les acides L ou D-glutamique ou le D-glucose (D-GFC) a été évaluée chez des plantules de ricin. Le test de systémie a montré que le L-aminoacide était nettement plus favorable à la mobilité phloémienne que l'acide D-aminé ou le D-glucose. Les résultats suggèrent que le conjugué fenpiclonil/L-aminoacide est reconnu et manipulé par un système de transport d'acide aminé stéréospécifique énergisé par la force proton-motrice. Des expériences complémentaires ont montré que le D-GFC était un inhibiteur puissant et sélectif de l'absorption du saccharose par les tissus foliaires et du chargement phloémien du saccharose. En raison de l'inhibition spécifique des transporteurs de saccharose (par exemple AtSUC2), le D-GFC peut être envisagé comme un nouvel outil en phloémologie.Enfin, nous avons exploré l'impact de la modification de structure de l'espaceur afin d'optimiser la stratégie de prodrogue. Après avoir introduit différentes structures d'espaceur entre le fenpiclonil et la fonction acide aminé, le conjugué qui contient un cycle triazole avec l'acide aminé comprenant la chaine la plus courte a montré la meilleure mobilité phloémienne et, par ailleurs, une systémie optimisée par rapport aux dérivés acides du fenpiclonil dans la gamme des valeurs de pH de l'apoplasme foliaire. / The purpose of our work is to develop a vectorization strategy to confer phloem mobility to agrochemicals by applying prodrug concept into agrochemical design. Fenpiclonil, a non-systemic fungicide from the phenylpyrrole family, was selected as a model parent compound and modified by associating it with an amino acid or a monosaccharide.The phloem mobility of L and D-glutamic acid and D-glucose fenpiclonil conjugates (D-GFC) was evaluated in Ricinus seedlings. The systemicity test showed that the L-amino acid promoiety was clearly more favorable to phloem mobility than D-amino acid or D-glucose. The results suggested that the transport of the L-amino acid conjugate is governed by a stereospecific amino acid carrier system energized by the proton motive force. Further investigation indicated that D-GFC was a potent and selective inhibitor of sucrose uptake by leaf tissues and sucrose phloem loading. Due to its specific inhibition of sucrose transporters (e.g. AtSUC2), D-GFC can be a candidate as a new tool in phloemology. Finally, we explored structural modifications of the spacer arm to optimize the prodrug strategy. Different structures of the spacer arm were introduced between fenpiclonil and the amino acid function. The conjugate which contains a triazole ring with the shortest amino acid chain showed the best phloem mobility and a better systemicity than fenpiclonil acidic derivatives within the pH range of the foliar apoplast.

Orientador: Carmen Regina Marcati / Resumo: A casca é um sistema biológico complexo que desempenha diversas funções na planta, incluindo condução de fotoassimilados, suporte mecânico, armazenamento de substâncias e proteção contra herbívoros, patógenos e intempéries como o fogo. A casca é composta, principalmente, pelo floema secundário e pela periderme, e reveste tanto caules quanto raízes. O caule está exposto à atmosfera e tem funções de elevação e suporte da planta, enquanto a raiz está exposta ao solo e tem funções de fixar a planta ao solo, armazenar substâncias e absorver e conduzir água e nutrientes. Contudo, pouco se sabe se as diferentes funções de caules e raízes indicam diferentes funções na casca de cada órgão. Neste trabalho, comparamos a casca de caules e raízes de 15 espécies representativas do cerrado paulista e testamos se a casca do caule apresentaria funções de suporte e proteção, enquanto a casca da raiz apresentaria função de armazenamento de substâncias. Também testamos se encontraríamos maior eficiência na condução de fotoassimilados na casca da raiz. Para tanto, selecionamos 15 espécies de árvores e arbustos do cerrado sensu stricto e amostramos a casca do caule e da raiz. Analisamos a estrutura (espessura e anatomia), a densidade e a química (água, açúcares solúveis, amido, nitrogênio, fósforo e carbono) e relacionamos com as funções da casca em cada órgão. Na casca do caule, encontramos maior espessura da periderme, devido ao felema mais largo com células maiores e mais espessas, e menor dens... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Bark is a complex biological system that performs multiple functions in plant, including photoassimilates conduction, mechanical support, storage and protection against herbivores, pathogens and fire. Bark comprises mainly the secondary phloem and the periderm, and covers both trunks and roots. The trunk is exposed to the atmosphere and has the main functions of plant elevation and plant support, whereas the root is exposed to the ground and has the main functions of fix the plant to the ground, store substances, provide water and nutrients to the plant. However, remain unclear whether the different functions of trunk s and roots indicate different functions in the bark of each organ. In this work, we compared the bark of trunk and roots of species in the cerrado of São Paulo, tested whether the trunk bark presents both support and protection functions, whereas the root bark presents storage function. We also tested whether we would find higher efficiency of photoassimilates conduction in the root bark. For this purpose, we selected 15 representative species of trees and shrubs in the cerrado sensu stricto and sample both trunk and root barks. We analyzed the structure (thickness and anatomy), density and chemistry (water, soluble sugars, starch, nitrogen, phosphorus and carbon) and associated to the bark functions in each organ. In the trunk bark, we found thicker periderm, due to thicker phellem with larger cell and thicker wall cells, and lower periderm density, suggesting... (Complete abstract click electronic access below) / Doutor

No description available.

Le projet de thèse consistait à étudier le mouvement du Virus de la jaunisse du navet (TuYV) dans le système vasculaire. Le premier objectif était d’identifier la nature du complexe viral cheminant dans les tubes criblés : virions et/ou complexes ribonucléoprotéiques. L’analyse du mouvement de mutants viraux dans différentes espèces végétales, en absence ou en présence de protéines de capside de type sauvage apportées en trans, a permis de démontrer une étroite relation entre la formation de virions et le transport à longue distance. Le second objectif de cette étude portait sur l’identification de partenaires cellulaires de la protéine P4 du TuYV. Deux protéines ont été identifiées par un criblage de banques d’ADNc d’A. thaliana par le système du double hybride dans la levure, et l’analyse de leur implication dans le cycle viral a été amorcée par des expériences de localisation subcellulaire et de validation fonctionnelle in planta. / In the project, Turnip yellows virus (TuYV) transport in the phloem was analysed. The first objective was to identify the nature of the viral complex involved in vascular movement: virions and/or ribonucleoprotein complexes. Mutant viruses were modified in the capsid protein gene to inhibit formation of virions. By analyzing their movement in different host plants, in the absence or in the presence of the wild-type capsid proteins brought in trans, we demonstrated a strong relation between virion formation and virus long-distance movement. The second objective was to identify cellular partners of the TuYV-P4 protein, a putative movement protein which is host-specific. Two proteins were identified by screening a cDNA library of A. thaliana using the yeast two hybrid technique, and their function in the virus cycle was assessed by performing sub-cellular localizations and infection of A. thaliana KO mutants.

No description available.

The chemical elicitor methyl jasmonate (MeJA) could replace insecticides in Europe and Asia for protection of young conifers against the pine weevil (Hylobius abietis). This thesis mainly focuses on the effects of MeJA treatment on chemical defenses of conifers from seedling batches with documented field resistance. Tissues of three pine species and one spruce species, with various treatments, were here extracted in hexane, whereafter volatile contents of tissues were separated and analyzed by 2D GC-MS. Induced responses of seedlings of Maritime pine (Pinus pinaster) and Monterey pine (Pinus radiata) to the folivore pine processionary (Thaumetopoea pityocampa), and the phloem-feeder H. abietis, have been studied. Amounts of mono- and sesqui-terpenes (and also non-volatile resin) in conifer tissues (needles and phloem) were less induced by T. pityocampa than by H. abietis. The MeJA-treated seedlings of Scots pine (Pinus sylvestris) changed their composition of phloem monoterpenes (induction of (-)-β-pinene), and were better protected in field than the seedlings of Norway spruce (Picea abies), which increased their total amounts of monoterpenes. Orientation bioassays with H. abietis showed deterrent effects of (-)-β-pinene, (+)-3-carene, (-)-bornyl acetate and 1,8-cineole. Conversely, (-)-α-pinene (induced in P. abies but not in P. sylvestris) was non-deterrent. MeJA-treated seedlings fed on by H. abietis contained higher amounts of the H. abietis antifeedant 2-phenylethanol, in tissues and emissions. Phloem of control seedlings instead induced the (+)-α-pinene, which is one of the enantiomers of the H. abietis attractant α-pinene. In response to MeJA treatment, the relative amounts of the (+)-α-pinene increased in the phloem of  P. radiata, while it decreased in P. pinaster phloem. The preference of H. abietis in the field for P. radiata before P. pinaster may be explained by these changes in enantiomers of the H. abietis attractant α-pinene. / Barrträd är viktiga för skogsindustrin. I Sverige består 57% av ytan av produktiv skogsmark, och av dessa träd utgörs 80% av gran och tall. Som försvar mot insekter och sjukdomar, producerar barrträden kådämnen. För unga barrträd i Europa och Asien är snytbaggen (Hylobius abietis) en allvarlig skadegörare, som orsakar skogsnäringen stora kostnader. För att skydda små gran- och tallplantor före utplanteringen, skulle växthormonet metyljasmonat (MeJA) kunna användas. I denna avhandling har effekter av MeJA-behandling och insektsangrepp undersökts på de två viktigaste barrträden i Sverige, tall och gran (Pinus sylvestris och Picea abies) och på två arter i medelhavsområdet (Pinus radiata och Pinus pinaster). De kemiska försvarsämnena i barrträd har analyserats för att utvärdera effekterna av MeJA-behandling. Vävnader från barrträd med olika behandling har extraherats i organiska lösningsmedel och dofterna från plantorna har insamlats genom fastfas-mikroextraktion. De flyktiga ämnena har separerats och identifierats med hjälp av gaskromatografi och masspektrometri (GC-MS). Dessutom har optiskt aktiva doftämnen separerats med hjälp av en tvådimensionell GC-MS. Plantornas olika försvarsreaktioner har studerats vid angrepp av snytbaggen, som är en floemätare, och av tallfjärilslarv (Thaumetopoea pityocampa), som huvudsakligen äter barr. De lättflyktiga ämnena (mono- och seskviterpener) och de icke-flyktiga ämnena (kådsyror) ökade mer i stam och barr från angrepp av H. abietis än av T. pityocampa. Sammansättning av monoterpener ändrades i de MeJA-behandlade tallplantorna i Sverige, specifikt ökade (-)-β-pinene i stamfloemet. Tallplantorna var bättre skyddade i fält än granplantorna, där den totala mängden monoterpener ökade. (-)-β-Pinene, (+)-3-carene, (-)-bornyl acetate och 1,8-cineole visade sig ha en negativ effekt på snytbaggens orientering mot talldoft i orienteringstester. En av monoterpenerna, (-)-α-pinene, som av MeJA-behandlingen inducerats i granen, men inte i tallen, hade ingen negativ effekt på snytbaggen. MeJA-behandlade tallplantor som angripits av snytbaggen, innehöll större mängder av snytbagge-äthämmaren 2-fenyletanol, både i vävnader och i emissioner. Stam från kontrollplantor inducerade istället (+)-α-pinene, vilken är en av de optiska isomererna av snytbagge-attrahenten α-pinene. För de spanska arterna, som svar på MeJA-behandling, ökade de lättflyktigaste terpenerna i barren hos P. radiata men inte hos P. pinaster, vilken redan innehöll en hög terpenhalt. De relativa mängderna av (+)-α-pinene ökade också i stammen hos P. radiata, medan de minskade i P. pinaster. I fält väljer snytbaggen att gå till P. radiata- framför P. pinaster-plantor, vilket kan vara kopplat till de skillnader i α-pinene-isomerer, vilka här har observerats. / <p>QC 20160304</p>

No description available.

During photosynthesis Plantaginaceae species can produce glucose derivatives such as iridoid glycosides and alcohol sugars that in addition to sucrose can be exported from leaves. Plantago lanceolata transported sorbitol in addition to sucrose especially at warmer leaf temperatures. However, two iridoids, catalpol and aucubin, found in P. lanceolata were not readily labelled from 14CO2 under any conditions examined. In contrast, in two greenhouse, cut-flower cultivars of Antirrhinum majus the iridoids, antirrhinoside and antirrhide, were readily 14C-labelled along with sucrose but little 14C was recovered in alcohol sugars (e.g., mannitol). The amount of 14C-partitioned into antirrhinoside increased at higher temperatures. Exposing leaves of P. lanceolata and A. majus to reduced-photorespiratory conditions (e.g. short-term CO2 enrichment and/or low O2) increased fixation and export. Under low O2 in P. lanceolata sorbitol 14C-labelling increased relative to sucrose and in A. majus 14C-labelling of sucrose increased relative to antirrhinoside. Also 14C-labelling of antirrhide increased more than antirrhinoside. During both short-term and long-term acclimation to high CO2, whole plant NCER, leaf photosynthesis and export increased in A. majus. Taken together the temperature and CO2 enrichment studies show plasticity in Plantaginaceae species to synthesize and transport sucrose and auxiliary glucose esters and alcohol sugars in a species-specific manner (depending on the rate of carboxylation).