Pas de résumé en français / In plants, long distance transport of sugars from photosynthetic source leaves to sink organs comprises different crucial steps depending on the species and organ types. Sucrose, the main carbohydrate for long distance transport is synthesized in the mesophyll and then loaded into the phloem. After long distance transport through the phloem vessels, sucrose is finally unloaded towards sink organs. Alternatively, sugar can also be transferred to non‐plant sinks and plant colonization by heterotrophic organisms increases the sink strength and creates an additional sugar demand for the host plant. These sugar fluxes are coordinated by transport systems. Main sugar transporters in plants comprise sucrose (SUTs) and monosaccharide (MSTs) transporters which constitute key components for carbon partitioning at the whole plant level and in interactions with fungi. Although complete SUTs and MSTs gene families have been identified from the reference Dicot Arabidopsis thaliana and Monocot rice (Oriza sativa), sugar transporter families of the leguminous plant Medicago truncatula, which represents a widely used model for studying plant-fungal interactions in arbuscular mycorrhiza (AM), have not yet been investigated.With the recent completion of the M. truncatula genome sequencing as well as the release of transcriptomic databases, monosaccharide and sucrose transporter families of M. truncatula were identified and now comprise 62 MtMSTs and 6 MtSUTs. I focused on the study of the newly identified MtSUTs at a full family scale; phylogenetic analyses showed that the 6 members of the MtSUT family distributed in all three Dicotyledonous SUT clades; they were named upon phylogenetic grouping into particular clades: MtSUT1-1, MtSUT1-2, MtSUT1-3, MtSUT2, MtSUT4-1 and MtSUT4-2. Functional analyses by yeast complementation and expression profiles obtained by quantitative RT-PCR revealed that MtSUT1-1 and MtSUT4-1 are H+/sucrose symporters and represent key members of the MtSUT family. Conservation of transport capacity between orthologous leguminous proteins, expression profiles and subcellular localization compared to previously characterized plant SUTs indicate that MtSUT1-1 is the main protein involved in phloem loading in source leaves whilst MtSUT4-1 mediates vacuolar sucrose export for remobilization of intracellular reserve.The AM symbiosis between plants and fungi from the phylum Glomeromycota is characterized by trophic exchanges between the two partners. The fungus supplies the autotrophic host with nutrients and thereby promotes plant growth. In return, the host plant provides photosynthate (sugars) to the heterotrophic symbiont. Here, sugar fluxes from plant source leaves towards colonized sink roots in the association between the model leguminous plant M. truncatula and the arbuscular mycorrhizal fungus (AMF) Glomus intraradices were investigated. Sugar transporter candidates from both the plant and fungal partners presenting differential expression profiles using available transcriptomic tools were pinpointed. Gene expression profiles of MtSUTs and sugar quantification analyses upon high and low phosphorus nutrient supply and inoculation by the AMF suggest a mycorrhiza-driven stronger sink in AM roots with a fine-tuning regulation of MtSUT gene expression. Conserved regulation patterns were observed for orthologous SUTs in response to colonization by glomeromycotan fungi.In parallel, a non-targeted strategy consisting in the development of a M. truncatula - G. intraradices expression library suitable for yeast functional complementation and screening of symbiotic marker genes, similar to the approach that led to the identification of the first glomeromycotan hexose transporter (GpMST1), has been developed in this study. [...]

The nutrient exchange between plant and fungus is the key element of the arbuscular mycorrhizal (AM) symbiosis. The fungus improves the plant’s uptake of mineral nutrients, mainly phosphate, and water, while the plant provides the fungus with photosynthetically assimilated carbohydrates. Still, the knowledge about the mechanisms of the nutrient exchange between the symbiotic partners is very limited. Therefore, transport processes of both, the plant and the fungal partner, are investigated in this study. In order to enhance the understanding of the molecular basis underlying this tight interaction between the roots of Medicago truncatula and the AM fungus Rhizophagus irregularis, genes involved in transport processes of both symbiotic partners are analysed here. The AM-specific regulation and cell-specific expression of potential transporter genes of M. truncatula that were found to be specifically regulated in arbuscule-containing cells and in non-arbusculated cells of mycorrhizal roots was confirmed. A model for the carbon allocation in mycorrhizal roots is suggested, in which carbohydrates are mobilized in non-arbusculated cells and symplastically provided to the arbuscule-containing cells. New insights into the mechanisms of the carbohydrate allocation were gained by the analysis of hexose/H+ symporter MtHxt1 which is regulated in distinct cells of mycorrhizal roots. Metabolite profiling of leaves and roots of a knock-out mutant, hxt1, showed that it indeed does have an impact on the carbohydrate balance in the course of the symbiosis throughout the whole plant, and on the interaction with the fungal partner. The primary metabolite profile of M. truncatula was shown to be altered significantly in response to mycorrhizal colonization. Additionally, molecular mechanisms determining the progress of the interaction in the fungal partner of the AM symbiosis were investigated. The R. irregularis transcriptome in planta and in extraradical tissues gave new insight into genes that are differentially expressed in these two fungal tissues. Over 3200 fungal transcripts with a significantly altered expression level in laser capture microdissection-collected arbuscules compared to extraradical tissues were identified. Among them, six previously unknown specifically regulated potential transporter genes were found. These are likely to play a role in the nutrient exchange between plant and fungus. While the substrates of three potential MFS transporters are as yet unknown, two potential sugar transporters are might play a role in the carbohydrate flow towards the fungal partner. In summary, this study provides new insights into transport processes between plant and fungus in the course of the AM symbiosis, analysing M. truncatula on the transcript and metabolite level, and provides a dataset of the R. irregularis transcriptome in planta, providing a high amount of new information for future works. / In der arbuskulären Mykorrhiza (AM) Symbiose werden die Wurzeln fast aller Landpflanzen von Pilzen der Abteilung Glomeromycota besiedelt. Der Pilz erleichtert der Pflanze die Aufnahme von Mineralien, hauptsächlich Phosphat, und Wasser. Im Gegenzug versorgt die Pflanze ihn mit Photoassimilaten. Trotz der zentralen Bedeutung der Austauschmechanismen zwischen Pilz und Pflanze ist nur wenig darüber bekannt. Um die molekularen Grundlagen der Interaktion zwischen den Wurzeln der Leguminose Medicago truncatula und dem arbuskulären Mykorrhizapilz Rhizophagus irregularis besser zu verstehen, werden hier die Transportprozesse, die zwischen den Symbiosepartnern ablaufen, näher untersucht. Die zellspezifische Regulation der Transkription potentieller M. truncatula Transporter Gene in arbuskelhaltigen und nicht-arbuskelhaltigen Zellen mykorrhizierter Wurzeln wird bestätigt. Ein Modell zur möglichen Verteilung von Kohlenhydraten in mykorrhizierten Wurzeln, nach dem Zucker in nicht-arbuskelhaltigen Zellen mobilisiert und symplastisch an arbuskelhaltige Zellen abgegeben werden, wird vorgestellt. Die Analyse eines Mykorrhiza-induzierten Hexose/H+ Symporter Gens, MtHxt1, liefert neue Einsichten in die Mechanismen der Kohlenhydratverteilung in mykorrhizierten Pflanzen. Metabolitanalysen von Wurzeln und Blättern einer knock-out Mutante dieses Gens zeigen dessen Einfluss auf den Kohlenhydrathaushalt der ganzen Pflanze und auf die Interaktion mit dem Pilz. Die Metabolitzusammensetzung von M. truncatula wird durch die Mykorrhiza Symbiose signifikant beeinflusst. Darüber hinaus werden durch Transkriptomanalysen die molekularen Grundlagen der AM Symbiose auf der Seite des Pilzes analysiert. Arbuskeln wurden mittels Laser Capture Mikrodissektion direkt aus mykorrhizierten Wurzeln isoliert. Über 3200 pilzliche Transkripte weisen in diesen Arbuskeln im Vergleich zu extraradikalen Geweben ein deutlich verändertes Expressionslevel auf. Unter diesen Transkripten sind auch sechs zuvor unbekannte Gene, die für potentielle Transporter codieren und mit großer Wahrscheinlichkeit eine Rolle im Nährstoffaustausch zwischen Pilz und Pflanze spielen. Während die Substrate von drei potentiellen MFS Transportern noch unbekannt sind, spielen zwei potentiellen Zuckertransporter möglicherweise eine Rolle im Transport von Kohlenhydraten in Richtung des Pilzes. Zusammengefasst bietet diese Arbeit neue Einsichten in Transportprozesse zwischen Pilz und Pflanze im Laufe der AM Symbiose. M. truncatula Transkript- und Metabolitlevel werden analysiert und die Transkriptomanalyse von R. irregularis liefert einen umfassenden Datensatz mit einer großen Menge an Informationen zu der noch unzureichend erforschten pilzlichen Seite der Symbiose für folgende Arbeiten.

Orchideoid mycorrhizal symbiosis (OM) can be found in nearly one tenth of higher plant species. This symbiosis is absolutely critical for orchids as they are unable to grow from seeds without external energy which is in nature provided by symbiotic fungi. The mechanism of transport between symbionts remains unknown. It is supposed that trehalose is one of the substances transported from fungi to plants as the source of energy. This thesis mainly aims to find out which other fungal saccharides could contribute to the process. The ability to utilize selected compounds was tested on protocorms of the common marsh orchid, Dactylorhiza majalis. The results showed that arabitol, erythritol, mannitol and sucralose are not utilized, while xylitol, sorbitol, glycerol and mannose are. Glutamin, an amino acid also suspected of participation in the OM transport, does not suffice as a source of energy. In orchids there were identified three groups of sequences coding for manitol dehydrogenase and two groups of sequences coding for sorbitol dehydrogenase. Key words: orchideoid mycorrhizal symbiosis, sugar alcohols, mannose, glutamine, carbon flow, energy flow, sorbitol dehydrogenase, in vitro

La symbiose mycorhizienne à arbuscules (MA) est une association bénéfique établie entre les membres d'un ancien sous-phylum de champignons, les Gloméromycètes, et les racines de la majorité des plantes terrestres. Les champignons MA procurent de l'eau et des minéraux (azote et phosphore principalement) à leur plante hôte et obtiennent de cette dernière des molécules carbonées sous forme d'hexoses et de lipides. Des études récentes ont montré que certaines protéines sécrétées par les champignons MA peuvent être des régulateurs importants de l'association (Kloppholz et al., 2011 ; Tsuzuki et al., 2016). Notre objectif était d'identifier de nouvelles protéines fongiques contribuant à la mise en place de la symbiose. Des protéines prédites pour être préférentiellement sécrétées par le champignon MA Rhizophagus irregularis dans les racines ont été identifiées au début de ma thèse (Kamel et al., 2017). Certaines d'entre-elles présentaient une structure ressemblant aux précurseurs de phéromones sexuelles d'Ascomycètes. Ces protéines sont connues pour être maturées dans les voies de sécrétion en petits peptides qui sont ensuite sécrétés. Leur reconnaissance par un récepteur couplé à la protéine G (GPCR) aboutit à la fusion cellulaire de deux types sexuels opposés. Dans le cas de R. irregularis, seule la reproduction clonale a été décrite, mais des données génomiques récentes remettent en question son statut d'organisme asexué (Ropars et al., 2016). Une grande partie de ma thèse a été dédiée à la caractérisation fonctionnelle de ce type de peptides chez R. irregularis. Nous avons montré que deux peptides étaient effectivement produits et sécrétés par R. irregularis. L'utilisation de peptides synthétiques nous a permis de mettre en évidence que l'un d'eux stimulait la colonisation de M. truncatula mais était également perçu par le champignon lui-même, induisant la transcription de son propre gène précurseur et d'un GPCR. Ce peptide stimulateur de la symbiose est composé de seulement trois acides aminés et il peut être produit à partir de trois précurseurs protéiques. Par des approches de génétique inverse (HIGS et VIGS), nous avons confirmé l'importance de ces précurseurs dans l'établissement de la symbiose.[...] / Arbuscular Mycorrhizal (AM) symbiosis is a beneficial association established between members of an ancient subphylum of fungi, the Glomeromycotina, and the roots of the majority of terrestrial plants. AM fungi provide water and minerals (mainly nitrogen and phosphorus) to their host plant in exchange for organic carbon in the form of hexoses and lipids. Recent studies have shown that certain proteins secreted by AM fungi are important symbiosis regulators (Kloppholz et al., 2011, Tsuzuki et al., 2016). Our aim was to identify new fungal proteins involved in the establishment of symbiosis. Proteins predicted to be preferentially secreted by the AM fungus Rhizophagus irregularis in the roots were identified at the beginning of my thesis (Kamel et al., 2017). We noticed that some of them had a structure resembling the sex pheromone precursors of Ascomycota. These proteins are known to be processed in the secretory pathway into small peptides which are then secreted. Their recognition by a G protein-coupled receptor (GPCR) leads to cell fusion of two opposite sex types. In the case of R. irregularis, only clonal reproduction has been described. However, recent genomic data question its status as an asexual organism (Ropars et al., 2016). A large part of my thesis was dedicated to the functional characterization of this type of processed peptides in R. irregularis. We show that two of them are actually produced and secreted by R. irregularis. Treatments with synthetic forms of these peptides revealed that one of them stimulated the colonization of M. truncatula but was also perceived by the fungus itself, inducing the transcription of its own precursor gene and of a GPCR gene. This symbiosis-stimulating peptide is composed of only three amino acids and can be produced from three different protein precursors. Using reverse genetics (HIGS and VIGS), we confirmed the importance of these precursors in the symbiosis establishment. [...]

In plants, long distance transport of sugars from photosynthetic source leaves to sink organs comprises different crucial steps depending on the species and organ types. Sucrose, the main carbohydrate for long distance transport is synthesized in the mesophyll and then loaded into the phloem. After long distance transport through the phloem vessels, sucrose is finally unloaded towards sink organs. Alternatively, sugar can also be transferred to non‐plant sinks and plant colonization by heterotrophic organisms increases the sink strength and creates an additional sugar demand for the host plant. These sugar fluxes are coordinated by transport systems. Main sugar transporters in plants comprise sucrose (SUTs) and monosaccharide (MSTs) transporters which constitute key components for carbon partitioning at the whole plant level and in interactions with fungi. Although complete SUTs and MSTs gene families have been identified from the reference Dicot Arabidopsis thaliana and Monocot rice (Oriza sativa), sugar transporter families of the leguminous plant Medicago truncatula, which represents a widely used model for studying plant-fungal interactions in arbuscular mycorrhiza (AM), have not yet been investigated.With the recent completion of the M. truncatula genome sequencing as well as the release of transcriptomic databases, monosaccharide and sucrose transporter families of M. truncatula were identified and now comprise 62 MtMSTs and 6 MtSUTs. I focused on the study of the newly identified MtSUTs at a full family scale; phylogenetic analyses showed that the 6 members of the MtSUT family distributed in all three Dicotyledonous SUT clades; they were named upon phylogenetic grouping into particular clades: MtSUT1-1, MtSUT1-2, MtSUT1-3, MtSUT2, MtSUT4-1 and MtSUT4-2. Functional analyses by yeast complementation and expression profiles obtained by quantitative RT-PCR revealed that MtSUT1-1 and MtSUT4-1 are H+/sucrose symporters and represent key members of the MtSUT family. Conservation of transport capacity between orthologous leguminous proteins, expression profiles and subcellular localization compared to previously characterized plant SUTs indicate that MtSUT1-1 is the main protein involved in phloem loading in source leaves whilst MtSUT4-1 mediates vacuolar sucrose export for remobilization of intracellular reserve.The AM symbiosis between plants and fungi from the phylum Glomeromycota is characterized by trophic exchanges between the two partners. The fungus supplies the autotrophic host with nutrients and thereby promotes plant growth. In return, the host plant provides photosynthate (sugars) to the heterotrophic symbiont. Here, sugar fluxes from plant source leaves towards colonized sink roots in the association between the model leguminous plant M. truncatula and the arbuscular mycorrhizal fungus (AMF) Glomus intraradices were investigated. Sugar transporter candidates from both the plant and fungal partners presenting differential expression profiles using available transcriptomic tools were pinpointed. Gene expression profiles of MtSUTs and sugar quantification analyses upon high and low phosphorus nutrient supply and inoculation by the AMF suggest a mycorrhiza-driven stronger sink in AM roots with a fine-tuning regulation of MtSUT gene expression. Conserved regulation patterns were observed for orthologous SUTs in response to colonization by glomeromycotan fungi.In parallel, a non-targeted strategy consisting in the development of a M. truncatula - G. intraradices expression library suitable for yeast functional complementation and screening of symbiotic marker genes, similar to the approach that led to the identification of the first glomeromycotan hexose transporter (GpMST1), has been developed in this study. [...]

La symbiose mycorhizienne à arbuscule est une interaction bénéfique entre les champignons du phylum Glomeromycota et près de 80% des espèces de plantes terrestres. Elle est caractérisée par un échange réciproque de nutriments dans lequel le champignon fournit des sels minéraux à la plante en échange de sucres issus de la photosynthèse. Cependant, cette "alimentation" du champignon au cours de la symbiose représente un coût carbone important pour la plante. Ainsi, les plantes doivent strictement maitriser le développement des champignons symbiotiques dans les racines. Ce contrôle est appelé autorégulation. Plusieurs protéines ont été démontrées comme étant importantes pour la régulation des différentes étapes de la colonisation : la stimulation de la croissance fongique dans la rhizosphère par les strigolactones, l'entrée dans les racines, la prolifération des hyphes au sein des racines et la formation des arbuscules. Dans ce travail, nous avons examiné plus en détail le rôle de deux de ces protéines connues pour être impliquées dans le processus de mycorhization, les facteurs de transcription NSP1 et NSP2 (Nodulation Signaling Pathway). Nous avons d'abord pu confirmer dans les racines de M. truncatula en conditions non-symbiotiques, l'implication directe de NSP1 dans la régulation de deux gènes de biosynthèse des strigolactones, DWARF27 (D27) et MORE AXILLARY GROWTH (MAX1). Ensuite, nous avons montré que NSP1, contrairement à NSP2, favorise l'entrée du champignon dans la racine, sans doute due à l'induction de la synthèse des strigolactones stimulant le champignon, via l'activation de D27 et de MAX1. Ensuite, au cours des étapes ultérieures de la mycorhization, nous avons montré que dans les tissus colonisés, NSP1 est absent et que l'induction de D27 et de MAX1 n'était plus NSP1 dépendante. À cette étape, l'expression de la protéine NSP1 est localisée dans les cellules justes en amont du front de colonisation fongique. Là, elle contrôle négativement la propagation des hyphes dans la racine et positivement la formation des arbuscules. En revanche, NSP2 est présente dans le tissu colonisé où elle favorise la propagation des hyphes et le développement des arbuscules, peut-être en interaction avec d'autres facteurs. Nous avons également montré chez M. truncatula que si les protéines NSP1 sont absentes des tissus colonisés, les transcrits de NSP1 sont présents. De façon inattendue, nous avons mis en évidence que l'ARN messager de NSP1 avait la capacité de protéger l'ARN messager de NSP2 contre sa dégradation par le microARN (miR171h), par une action de piégeage du miR171h, appelé effet mimicry. Ceci est la première démonstration qu'une molécule d'ARN codante peut être la cible mimétique d'un microARN. Dans notre contexte d'étude cette constatation révèle que les transcrits de NSP1 permettent une régulation positive de l'expression de NSP2, et met en lumière un niveau de complexité supplémentaire dans le rôle de ces deux facteurs de transcription dans la symbiose mycorhizienne. Enfin, dans la tomate, nous avons montré que Sl-NSP1 pourrait être directement ou indirectement régulée par une protéine AUX / IAA impliquée dans la réponse précoce à l'auxine, Sl-IAA27. Ce lien avec l'auxine nous fait présumer que cette AUX/AAI est un nouveau composant de la voie de signalisation du contrôle de la colonisation fongique dans la tomate, et nous proposons qu'il puisse avoir un rôle dans le contrôle de la biosynthèse des strigolactones via la régulation de Sl-NSP1. L'ensemble de ce travail fournit de nouvelles pièces du puzzle constituant la symbiose mycorhizienne et montre l'importance de l'analyse des régulations spatiotemporelles pour une meilleure compréhension de ces processus biologiques extrêmement complexes. / The arbuscular mycorrhiza (AM), a symbiosis between fungi from the phylum Glomeromycota and nearly 80% of terrestrial plant species. It is characterized by a two-way exchange in which the fungus provides mineral nutrients to the plant in exchange for carbohydrates. However this "feeding" of the fungus during the symbiotic process represents a significant carbon cost for the plant. To maintain a mutualistic interaction the two symbiotic partners have to strictly control the extent of fungal development in the roots. This control is called autoregulation. Several proteins have been found to be important for the regulation of the different mycorrhizal steps: the stimulation of fungal growth in the rhizosphere by the strigolactones, the fungal entrance in the roots, the hyphal proliferation in the roots and the arbuscule formation. In this work we examine in more detail the role of two of these proteins known to be involved in the mycorrhization process, the transcriptional factors NSP1 and NSP2 (Nodulation Signaling Pathway). We first confirm in M. truncatula roots the direct implication of NSP1 in the regulation of two strigolactone biosynthesis genes, DWARF27 (D27) and MAX1, during the asymbiotic conditions. Then, we show that NSP1, unlike NSP2, is a factor that promotes the fungal entries in the root, presumably due to its activation of D27 and MAX1 resulting in a stimulation of strigolactone synthesis and presymbiotic fungal growth. Next, during the later stages of mycorrhization, we highlight that in the colonized tissues NSP1 is absent and the induction of both D27 and MAX1 is not anymore NSP1 dependent. NSP1 protein is then localized in cells which are not yet colonized but are close to a colonization zone. There, it controls negatively the hyphal propagation in the root and positively the formation of arbuscules. In contrast, NSP2 is present in the colonized tissue where it promotes hyphal propagation and arbuscule development, perhaps by interacting with other proteins. We also show that if NSP1 proteins are absent of the colonized tissues, NSP1 transcripts are present. Unexpectedly, we unveil that in those colonized cells, NSP1 mRNA can protect, by a micro RNA (miR171h) decoy action called target mimicry, NSP2 mRNA against miR171h-mediated degradation. This is the first demonstration that a coding RNA molecule can be a target mimic for a microRNA. In our context this finding reveals a positive regulation of NSP2 expression by NSP1 transcripts and brings to light an additional layer of complexity in the mycorrhizal dual role of these two transcription factors. Finally, in tomato, we highlight that SlNSP1 could be directly or indirectly regulated by the AUX/IAA protein, SlIAA27. As a link with auxin we presume that this AUX/IAA protein is a new component of the signaling pathway controlling AM fungal colonization in tomato, and we propose that it controls strigolactone biosynthesis via the regulation of SlNSP1. Overall our work provides new pieces of the mycorrhizal puzzle and shows how important it is to perform spatiotemporal investigations for a better understanding of highly integrated and complex biological processes.

Les symbioses bactérie-légumineuse (nodulation) et champignon-plante (mycorhization) présentent un intérêt agrobiologique et écologique majeur ; elles permettent aux plantes de croître naturellement sur un sol aride et peu fertile. Il a été démontré très récemment que les signaux impliqués dans la mise en place de la symbiose endomycorhizienne à arbuscule (facteurs "Myc") sont très proches de ceux de la nodulation. Il s'agit de molécules appartenant à la famille des lipo-chitooligosaccharides. Afin de réaliser la synthèse de ces molécules, deux nouvelles méthodologies ont été développées. L'ouverture oxydante d'acétals de 4,6-O-benzylidène de plusieurs glycopyranosides (en série gluco, galacto et manno) par le diméthyldioxirane (DMDO) a été étudiée. Le contrôle de la régiosélectivité a été effectué grâce au groupement protecteur introduit sur la fonction alcool de la position 3. La formation directe de β-glycosides de la N-acétyl-D-glucosamine par catalyse au triflate de fer (III) a été étudiée. La réaction a été menée sous irradiation micro-ondes ou en flux continu (système minifluidique Vapourtec®). Une nouvelle stratégie pour la synthèse du facteur [Myc-IV (C16:0, S)] a ensuite été établie. Nous avons utilisé un réactif peu toxique et non odorant pour introduire le motif thio nécessaire à la formation de deux liaisons glycosidiques. Le disaccharide précurseur de l'unité réductrice a été obtenu grâce à la première méthodologie développée au cours de cette thèse. / Arbuscular mycorrhiza (AM) is a root endosymbiosis between plants and fungi. It has an agrobiological interest and a crucial ecological importance because it allows plants to grow on aride and infertile soil. Recently, the structure of the symbiotic signal "Myc factor" was identified as a mixture of lipochitooligosaccharides (LCOs). In order to propose a new synthesis of LCOs, we developed two green methodologies in glycochemistry. We performed the oxidative cleavage of 4,6-O-benzylidene acetals of various glycopyranosides (gluco, manno and galacto series) with dimethyldioxirane (DMDO) and its regioselective control with a suitable protecting group at position 3. We investigated the formation of β-glycoside of N-acetyl-D-glucosamine using catalytic iron (III) triflate. The reaction can be performed using microwave irradiation or, for scale-up synthesis, flow chemistry using Vapourtec® minifluidic system. We establish a new strategy for the total synthesis of the most abundant Myc factor [Myc-IV (C16:0, S)]. We used odorless and few toxic MbpSH reagent to introduce the activated thio residue involved in two glycosylation reactions. The disaccharide acceptor precursor of the reducing end was obtained after oxidative cleavage of the 4,6-O-benzylidene moiety by DMDO.

Some microorganisms are known to form mutualistic symbiosis with plant roots and by their impact they can improve some plant parameters. These symbiotic microorganisms, which are able to improve some plant parameters, include especially mycorrhizal fungi, plant growth promoting bacteria and some saprotrophic mycoparasitical fungi. Mechanisms of changes of these parameters, as influenced by symbiotic microorganisms, are known only in part and nowadays are being actively researched. Aims of this work were to find out if selected microbial treatments influence selected growth, physiological and yield parameters of plants and contents of selected substances in fruits. Within this work were made three pot greenhouse experiments (experiments 1, 2 and 3) and three pilot greenhouse experiments (experiments 4, 5 and 6), performed on tomato (Solanum lycopersicum) and cucumber (Cucumis sativus) plants. Plants were grown in hydroponics using a carrier of rockwool and they were watered by nutrient solution. As microbial treatments for plants in experiments have been used a mixture of arbuscular mycorrhizal fungi (AM), mixture of plant growth promoting bacteria (PGPB), saprotrophic mycoparasitical fungus Trichoderma harzianum (Th) and various mutual combinations of these treatments. There have been observed...