Root symbioses with arbuscular mycorrhizal fungi and rhizobial bacteria share a common signaling pathway in legumes. Among the common symbiosis genes are CASTOR and POLLUX, the twin homologous genes in Lotus japonicus that encode putative ion channel proteins. Orthologs of CASTOR and POLLUX are ubiquitously present in both legumes and non-legumes, but their function in non-legumes remains to be elucidated. Here, we use reverse genetic approaches to demonstrate that the rice (Oryza sativa) ortholog of POLLUX, namely Os-POLLUX, is indispensible for mycorrhizal symbiosis in rice. Furthermore, we show that Os-POLLUX can restore nodulation, but not rhizobial infection, to a M. truncatula dmi1 mutant.

Ectomycorrhizal colonisation potential of Pinus radiata seedlings inoculated with the commercially available Trichoderma species bio-inoculant, Arbor-Guard™, was investigated in a commercial containerised nursery setting and in a separate glasshouse experiment, which included the co-inoculation of specific ectomycorrhizal fungi. Application of Arbor-Guard™ to Pinus radiata seedlings in a containerised commercial nursery had no significant effect on the ability of the naturally occurring ectomycorrhizal (ECM) fungi to colonise the seedlings. Thelephora terrestris was the dominant ectomycorrhizal species colonising the P. radiata root tips and has been described as a species able to rapidly outcompete other ECM species colonisation, particularly in high organic matter media like that used at the containerised commercial nursery investigated. In a similar experiment run to augment the commercial experiment, specific ECM fungi identified as Rhizopogon roseolus, Suillus luteus, and Rhizopogon villosulus were co-inoculated with Arbor-Guard™ to investigate the effect on the colonisation potential of the respective ECM species in combination with Trichoderma. The treatment effect of the addition of Arbor-Guard™ did not negatively impinge on the ECM species found, or the abundance of ECM root tips colonising the P. radiata seedlings. Ectomycorrhizal species in the Thelephoraceae family were the dominant species found colonising the P. radiata root tips. Of the inoculated ECM, S. luteus was the only detected species colonising the P. radiata root tips but was only found in low abundance. Non-conducive abiotic factors for optimum ECM colonisation were considered the most likely reason for the low colonisation of the inoculated ECM species. Any effect of the unintentional co-inoculation of the wood decaying fungi Hypholoma fasciculare and Lentinula edodes, due to misidentification, with the inoculated ECM species was unable to be resolved in this study. However, it was speculated that H. fasciculare may have had a negative effect on the inoculated ECM species colonisation. In vitro dual culture assays were initiated to investigate the specific interactions between each of the candidate ECM fungi inoculated in the glasshouse experiment when challenged with each of the six Trichoderma isolates in Arbor-Guard™. Both competition for nutrients and/ or space were concluded to be the main antagonistic mechanisms potentially used by five of the Trichoderma isolates against all co-inoculated ECM species and L. edodes. Hypholoma fasciculare was not inhibited by the five Trichoderma isolates, however, one Trichoderma isolate (LU 663) competitively antagonised all inoculated ectomycorrhizal/ saprophytic species before the mycelial fronts converged. Agar diffusible secondary metabolites were speculated to be potential mechanism of antagonism expressed by LU 663 over volatile antibiotics such as 6-pentyl-α-pyrone. No direct correlation could be dervived from the in vitro dual culture assays and what was observed in the containerised in planta results. Overall the results indicated no negative impact of the Trichoderma bio-inoculant Arbor-Guard™ on ectomycorrhizal colonisation of Pinus radiata seedlings in a containerised nursery system.

Dans les sols, les champignons ectomycorhiziens (ECM) forment une symbiose très répandue avec les racines des arbres et contribuent ainsi à leur croissance et à leur santé. Des études antérieures ont montré que certaines bactéries pouvaient influencer positivement la symbiose entre les ECM et les arbres, appelées BAM pour Bactéries Auxiliaires de la Mycorhization. Les mécanismes de l’effet auxiliaire des BAM sont encore peu connus. En amont de cette thèse, il avait été montré in vitro que la BAM Pseudomonas fluorescens BBc6 formait des structures similaires à des biofilms sur les hyphes de l'ECM Laccaria bicolor. Dans ce contexte, afin d'enrichir les connaissances concernant les interactions entre les ECM et les BAM, cette thèse a porté sur l'interaction physique entre ces deux organismes. L'étude a en partie été réalisée via une méthode d'analyse par microscopie confocale, développée durant cette thèse. Les résultats obtenus ont montré que cette bactérie formait des biofilms localisés préférentiellement sur la région apicale des colonies de l'ECM ce qui pourrait indiquer une interaction trophique. L'existence d'une telle interaction a d'ailleurs par la suite été confirmée. Les résultats ont également montré que l'interaction physique entre Laccaria bicolor et BBc6 n'est pas spécifique puisque l'ensemble des treize autres souches bactériennes testées a formé des biofilms sur les hyphes de Laccaria bicolor. En revanche, BBc6 s'est montrée incapable de former des biofilms sur certains champignons appartenant aux Ascomycètes, suggérant des mécanismes d'inhibition. De plus, l'étude de la matrice des biofilms formés par BBc6 a révélé la présence de réseaux de filaments constitués d'ADN qui semblent structurer ces biofilms et qui ont aussi été observés chez l'ensemble des souches bactériennes testées. Ces résultats révèlent un rôle structural de la molécule d'ADN qui, bien qu'il semble répandu, n'a que peu été reporté jusqu'à présent. Enfin, il a été montré que des mutants de BBc6 qui ont perdu leur effet auxiliaire forment des biofilms différents de la souche sauvage sur une surface abiotique suggérant un lien potentiel entre l'effet auxiliaire et la formation de biofilms / In soil ecosystems, ectomycorrhizal fungi (ECM) form a widespread symbiosis with roots of trees, contributing to tree growth and health. It has been shown that some bacteria, called mycorrhization helper bacteria (MHB), stimulate mycorrhizal symbiosis. The mechanisms of this helper effect are poorly understood. Previous studies have shown that the MHB Pseudomonas fluorescens BBc6 formed biofilm-like structures around the hyphae of the ECM Laccaria bicolor during their in vitro interaction. In this context, in order to increase knowledge concerning MHB/ECM interactions, the work presented here focuses on the physical interaction between these two organisms. To this purpose, a method of analysis based on confocal microscopy was developed. The results showed that the bacteria formed biofilms preferentially localized on the apical region of the ECM colonies, which could indicate a trophic interaction. Such an interaction has been subsequently confirmed. The results also showed that the physical interaction between L. bicolor and BBc6 is not specific since all thirteen other bacterial strains tested formed biofilms on the hyphae of L. bicolor. On the other hand, BBc6 was unable to form biofilms on some fungi belonging to Ascomycetes, suggesting the existence of inhibition mechanisms. Moreover, the study of the BBc6 biofilm matrix revealed networks of DNA-containing filaments which seem to structure these biofilms and which have also been observed in all the bacterial strains tested. These results reveal a structural role of the DNA molecule, a role that has been rarely reported so far despite its probable high occurrence. Finally, it has been shown that BBc6 mutants having lost their helper effect presented a modified phenotype concerning their biofilm formation on abiotic surface, suggesting a potential link between the helper effect and the biofilms formation

Made available in DSpace on 2014-06-11T19:29:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-07-30Bitstream added on 2014-06-13T18:59:17Z : No. of bitstreams: 1 scabora_mh_me_ilha.pdf: 168017 bytes, checksum: 044a7eb62fa7c98f543c3a7e851d2e1d (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A construção de usinas hidrelétricas, mesmo que necessária, causam degradação do solo, expondo o subsolo e originar as áreas de empréstimo. Intervenções nessas áreas, escolhendo metodologia e selecionando espécies de plantas, podem acelerar sua regeneração, permitindo o processo sucessional. Fungos micorrízicos são eficientes na aquisição de água e nutrientes do solo, melhorando o crescimento das plantas, além de participar da agregação e estruturação do solo e, conseqüentemente, na sua recuperação. Esse trabalho teve o objetivo de avaliar a atividade microbiana (quantificação do carbono de CO2 liberado), fertilidade e a diversidade de fungos micorrízicos arbusculares (FMA) de espécies arbóreas de cerrado, crescendo em áreas de cerrado degradadas. O experimento foi conduzido na Fazenda de Ensino, Pesquisa e Extensão (FEPE), da UNESP- Universidade Estadual Paulista, Faculdade de Engenharia de Ilha Solteira, localizada no município de Selvíria-MS, Brasil. O delineamento experimental foi o de blocos ao acaso, em fatorial 2 x 11, ou seja, duas áreas (pastagem degradada e subsolo exposto) e 11 espécies arbóreas, com quatro repetições, composta cada uma pela média de cinco plantas por espécie arbórea, por repetição. Nas covas foram depositados adubos orgânicos (1 1/2 composto) e químico (baseado no resultado da análise química), além de 50 mL de solo proveniente de uma área preservada de cerrado, como fonte de inóculo de microrganismos. Após dois anos de implantação do experimento, o solo e subsolo foram coletados, na profundidade 0 - 0,10 m) e usados na avaliação das características químicas e microbiológicas, como: quantificação do carbono do CO2 (C-CO2) liberado, número de esporos de FMA, porcentagem de colonização por FMA (COL)... / The construction of hydreletric, even so necessaries, causes soil degradation, and may expose the subsoil and originate the soil borrow areas. Interventions in such degraded areas, choosing metodologies and selecting plant species, can accelerate its regeneration, allowing the succession process. Mycorrhizal fungi are efficients on the transfering of water and nutrients from the soil to the plant, increasing the plant growth, as well as, participating on soil agregation and structuration process and, consequentely, its recuperation. This research had as objective to evaluate the microbial activity (quantification of evolution CO2 carbon (CCO2)), soil fertility and diversity of arbuscular mycorrhizal fungi (AMF) in tree species, growing in degraded cerrado areas. The research was conducted at the Teaching, Research and Extension Farm, UNESP - São Paulo State University, the College of Engineering of Ilha Solteira, located at Selvíria, Mato Grosso do Sul State, Brazil. The experimental design was a randomized complete block design in a 2 x 11 factorial, i.e., two areas (degraded pasture soil and exposed subsoil) and 11 tree species, with four replications, each one consisting of five plants. On the pit were dumpped organic (1 1/2 L de compostagem) and chemical (based on the chemical analysis results) fertilizers and 50 mL of. soil from a cerado preserved areas as microrganisms inoculum. One year after the deployment of the experiment, soil / subsoil and roots were collected (depth of 0,00 - 0,10 m) and used to evaluate chemical and microbialogical characteristics, such as, quantification of evoluted CCO2 (C-CO2), number of AMF spores (NSPO), percentage of arbuscular mycorrhizal colonization (COL) and identification of the native AMF species. Conclusion: a) after two years, the subsoil remained poor in nutrients, when compared to...(Complete abstract click electronic access below)

Orientador: Ana Maria Rodrigues Cassiolato / Banca: Francisco Maximino Fernandes / Banca: Rosilaine Carrenho / Resumo: A construção de usinas hidrelétricas, mesmo que necessária, causam degradação do solo, expondo o subsolo e originar as "áreas de empréstimo". Intervenções nessas áreas, escolhendo metodologia e selecionando espécies de plantas, podem acelerar sua regeneração, permitindo o processo sucessional. Fungos micorrízicos são eficientes na aquisição de água e nutrientes do solo, melhorando o crescimento das plantas, além de participar da agregação e estruturação do solo e, conseqüentemente, na sua recuperação. Esse trabalho teve o objetivo de avaliar a atividade microbiana (quantificação do carbono de CO2 liberado), fertilidade e a diversidade de fungos micorrízicos arbusculares (FMA) de espécies arbóreas de cerrado, crescendo em áreas de cerrado degradadas. O experimento foi conduzido na Fazenda de Ensino, Pesquisa e Extensão (FEPE), da UNESP- Universidade Estadual Paulista, Faculdade de Engenharia de Ilha Solteira, localizada no município de Selvíria-MS, Brasil. O delineamento experimental foi o de blocos ao acaso, em fatorial 2 x 11, ou seja, duas áreas (pastagem degradada e subsolo exposto) e 11 espécies arbóreas, com quatro repetições, composta cada uma pela média de cinco plantas por espécie arbórea, por repetição. Nas covas foram depositados adubos orgânicos (1 1/2 composto) e químico (baseado no resultado da análise química), além de 50 mL de solo proveniente de uma área preservada de cerrado, como fonte de inóculo de microrganismos. Após dois anos de implantação do experimento, o solo e subsolo foram coletados, na profundidade 0 - 0,10 m) e usados na avaliação das características químicas e microbiológicas, como: quantificação do carbono do CO2 (C-CO2) liberado, número de esporos de FMA, porcentagem de colonização por FMA (COL) ...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The construction of hydreletric, even so necessaries, causes soil degradation, and may expose the subsoil and originate the "soil borrow areas". Interventions in such degraded areas, choosing metodologies and selecting plant species, can accelerate its regeneration, allowing the succession process. Mycorrhizal fungi are efficients on the transfering of water and nutrients from the soil to the plant, increasing the plant growth, as well as, participating on soil agregation and structuration process and, consequentely, its recuperation. This research had as objective to evaluate the microbial activity (quantification of evolution CO2 carbon (CCO2)), soil fertility and diversity of arbuscular mycorrhizal fungi (AMF) in tree species, growing in degraded cerrado areas. The research was conducted at the Teaching, Research and Extension Farm, UNESP - São Paulo State University, the College of Engineering of Ilha Solteira, located at Selvíria, Mato Grosso do Sul State, Brazil. The experimental design was a randomized complete block design in a 2 x 11 factorial, i.e., two areas (degraded pasture soil and exposed subsoil) and 11 tree species, with four replications, each one consisting of five plants. On the pit were dumpped organic (1 1/2 L de compostagem) and chemical (based on the chemical analysis results) fertilizers and 50 mL of. soil from a cerado preserved areas as microrganisms inoculum. One year after the deployment of the experiment, soil / subsoil and roots were collected (depth of 0,00 - 0,10 m) and used to evaluate chemical and microbialogical characteristics, such as, quantification of evoluted CCO2 (C-CO2), number of AMF spores (NSPO), percentage of arbuscular mycorrhizal colonization (COL) and identification of the native AMF species. Conclusion: a) after two years, the subsoil remained poor in nutrients, when compared to...(Complete abstract click electronic access below) / Mestre

Pollution et agriculture urbaine (AU) sont deux mondes interconnectés soumettant les villes au défi de la durabilité, dans un contexte où la pollution aux metalloïdes augmente au moins autant que l'intérêt pour l'agriculture urbaine. Les biofertilisants / bioamendements utilisés en AU (champignons mycorhiziens à arbuscules, compost, biochar) peuvent influencer la mobilité des polluants du sol. Cette étude vise à mieux comprendre le devenir de contaminants inorganiques géogéniques et anthropiques, majeurs (Cd, Pb) ou émergents (Sb), dans des systèmes sol-plante-biofertilisant et leur bioaccessibilité pour l'homme. Si la mobilité des polluants est modifiée par les biofertilisants, le type de source influence aussi leur bioaccessibilité. La communauté fongique semble cruciale dans ces phénomènes mais est impactée par l'ajout de compost. Ainsi, l'utilisation de ces biofertilisants sur sol pollué est à raisonner du fait des interactions multiples affectant la phytodisponibilité des polluants. / Urban agriculture (UA) and pollution are two worlds more inter-connected every day, creating one of the main challenges of sustainable cities as persistent metal(loid) contamination increases as much as the interest for urban agriculture. Biofertilizers and bioamendments used in UA (arbuscular mycorrhizal fungi, compost, and biochar) can influence the mobility of contaminants in soil. This study aims to better understand the fate of anthropic or geogenic, major (Cd, Pb) and emerging (Sb), inorganic contaminants in soil-plant-biofertilizer systems and their human bioaccessibility. While contaminant mobility in soil is affected by biofertilizers, their origin influences also their bioaccessibility. The fungal community seems crucial in this phenomenon but is impacted by compost addition. Hence, using these biofertilizers in contaminated soils has to be thought wisely because of the multiple interactions affecting contaminant's phytoavailability.

Le but du projet est de mettre au point de nouveaux outils enzymatiques permettant la production de chitinoligosaccharides de taille et de degré d'acétylation parfaitement contrôlés pour l'étude d'enzymes impliquées dans la biosynthèse, la biodégradation et la modification de la chitine, et pour l'étude de récepteurs protéiques d'origine animale ou végétale. Des études récentes ont montré que les oligomères de la chitine et leurs dérivés sont des molécules qui interviennent dans les phénomènes symbiotiques et de reconnaissance hôte-pathogène dans le règne végétal. Ces molécules sont utilisées en agrochimie comme biofertilisants, et potentiellement en phytosanitaire. Ils sont connus également pour posséder de nombreuses activités biologiques dans le domaine de la santé (effets antimicrobiens, anticancéreux, anti-inflammatoires, immunostimulants...). Si les activités de cette classe d'oligosaccharides sont parfaitement reconnues, leurs modes d'actions restent encore à éclaircir, ce qui nécessite de disposer de molécules pures aux structures chimiques parfaitement contrôlées. La production d'oligomères de la chitine nécessite traditionnellement la mise en œuvre d'une chimie fastidieuse, qui peut être facilitée par une approche chimio-enzymatique.Dans le cadre de cette thèse, nous souhaitons donc développer des outils enzymatiques permettant la synthèse d'une bibliothèque de molécules de taille et de degré d'acétylation contrôlés en vue d'études structure-activité biologique. Pour cela, nous chercherons à produire des N-désacétylases et des chitinases dans différents systèmes d'expression et à caractériser leur activité afin de générer une panoplie de molécules de structure moléculaire parfaitement définie à partir de fragments saccharidiques issus de la biomasse. Les molécules ainsi préparées pourront ensuite être modifiées de façon chimio-sélective afin d'obtenir des sondes photoactivables et/ou biotinylées pour la caractérisation de récepteurs, des substrats fluoro- ou chromogéniques pour le dosage spécifique d'activités enzymatiques ou encore des lipochitinoligosaccharides capables de favoriser la croissance des plantes. Les approches utilisées pour mener à bien ce projet pluridisciplinaire seront : l'ingénierie et la production de protéines recombinantes, la caractérisation biochimique d'activités enzymatiques ainsi que la synthèse chimio-enzymatique et la modification chimique d'oligosaccharides qui devront être caractérisés d'un point de vue physicochimique. Il s'agit d'un projet intégré dans une collaboration nationale financée par l'ANR réunissant des équipes de l'Université de Grenoble, de Lyon, d'Orsay, et l'entreprise Bayer CropScience. / The aim of the project is to develop new tools for enzymatic production of chitooligosaccharides size and degree of acetylation perfectly controlled for the study of enzymes involved in biosynthesis, biodegradation and modification of chitin and for the study of protein receptors of animal or vegetable origin. Recent studies have shown that oligomers of chitin and its derivatives are molecules involved in the phenomena of symbiotic and host-pathogen recognition in plants. These molecules are used as agrochemicals biofertilizers. They are also known to possess numerous biological activities in the field of health (anti-microbial, anti-cancer, anti-inflammatory, immunostimulant ...). If the activities of this class of oligosaccharides are well recognized, their modes of action remain to be clarified, which requires having pure molecules with chemical structures perfectly controlled. The production of chitin oligomers traditionally requires the implementation of a tedious chemistry, which can be facilitated by a chemoenzymatic approach.As part of this thesis, we want to develop enzymatic tools for the synthesis of a library of molecules of size and degree of acetylation controlled studies for structure-biological activity. For this, we will seek to produce N-deacetylase and chitinases in different expression systems and characterize their activity to generate a variety of molecules well-defined molecular structure from saccharide fragments derived from biomass. The molecules thus prepared can then be modified so as to achieve chemoselective photoactivatable probes and / or biotinylated for the characterization of receptors, substrates or fluoro-chromogenic assay for specific enzyme activities or lipo-chitooligosaccharides can promote plant growth. The approaches used to complete this multidisciplinary project are: engineering and production of recombinant proteins, the biochemical characterization of enzymatic activities and chemoenzymatic synthesis and chemical modification of oligosaccharides to be characterized from the point of physicochemical view. This is an integrated project in a national collaboration funded by the ANR with teams from the University of Grenoble, Lyon, Orsay, and Bayer CropScience.

Made available in DSpace on 2015-03-26T13:51:45Z (GMT). No. of bitstreams: 1 texto completo.pdf: 2830202 bytes, checksum: 646d57cf2258798f7f8bcfe375e2b6ab (MD5) Previous issue date: 2009-03-16 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Hydnangium sp. is a basidiomycetous fungus that is capable of forming ectomycorrhiza with Eucalyptus species. The in vitro mycorrhization system is widely used for mycorrhizal interactions studies, becoming a simple and reproducible system for the symbiosis-regulated genes expression analysis. In this work, the in vitro mycorrhization system for the Hydnangium sp. and Eucalyptus grandis interaction was performed for the colonization, differentiation and functioning phases for the ectomicorriza formation. The colonization phase were verified after five days of inoculation with the Hydnangium sp., the differentiation phase after ten days and the functioning phase after 20 days of inoculation. The extern morphology was analyzed by stereomicroscopy and the section microscopy was performed for the mantle and Hartig net detection. The total RNA extraction was performed for each phase, with the objective of to analyze genes expression. However, the material quantity from roots of 130 seedlings for each phase was insufficient for the transcripts detection through RTPCR. The intron analysis of the partial sequences of the genes that encode ATP sintase (atp) and acetyl-CoA acetyltransferase (aat) of Hydnangium sp. enabled two introns identification in partial sequence of atp gene (53 and 65 bp), while in partial sequence of aat gene were identified three introns (52, 52 e 46 bp). All introns analyzed have the canonical sequence 5 GT 3 AG on splicing sites, ranging the adjacent nucleotides. The phylogenetic analysis, using the partial sequences of amino acids of atp and aat genes, enabled the correct group separation, corroborating the Hydnangium sp. classification as belonging the same family of Laccaria bicolor. / Hydnangium sp. é um fungo basidiomiceto capaz de formar ectomicorriza com espécies de Eucalyptus. Os sistemas de micorrização in vitro vêm sendo largamente utilizados para estudar interações micorrízicas, tornando-se um sistema simples e reproduzível para as análises de expressão de genes envolvidos na interação. Neste trabalho, a técnica de micorrização in vitro para a interação do fungo Hydnangium sp. com E. grandis foi realizada para as fases de colonização, diferenciação e funcionamento da ectomicorriza. A fase de colonização foi verificada após cinco dias de inoculação com Hydnangium sp., a fase de diferenciação após 10 dias e a fase de funcionamento após 20 dias de inoculação. A morfologia externa foi analisada por lupa e foram avaliados cortes microscópicos para a detecção do manto e da rede de Hartig. A extração de RNA total foi realizada para cada uma das fases, com o objetivo de analisar a expressão gênica. Entretanto, a quantidade de material proveniente de raízes de 130 plântulas para cada fase, foi insuficiente para a detecção de transcritos por meio de RTPCR. A análise dos íntrons das seqüências parciais dos genes que codificam ATP sintase (atp) e acetil-CoA acetiltransferase (aat) de Hydnangium sp. permitiu a identificação de dois íntrons na seqüência parcial do gene atp (53 e 65 pb), enquanto que na seqüência parcial do gene aat foram identificados três íntrons (52, 52 e 46 pb). Todos os íntrons analisados possuem a seqüência padrão 5 GT 3 AG no sítio de processamento, variando os nucleotídeos adjacentes. A análise filogenética, utilizando as seqüências parciais de aminoácidos deduzidas dos genes atp e aat, permitiu a separação correta dos grupos, corroborando a classificação do fungo Hydnangium sp. como pertencente à mesma família de Laccaria bicolor.

Le jujubier (ou Ziziphus mauritiana Lam.) est une espèce à usages multiples (fruits, fourrage, bois de service) prioritaire pour le reboisement et l’arboriculture fruitière dans le Sahel. Dans ce contexte où les sols sont souvent dégradés et pauvres en minéraux (P en particulier), la mycorhization et la fertilisation phosphatée pourraient jouer un rôle important dans l’amélioration de la croissance et de la productivité des jujubiers.L’objectif principal de ce travail était d’améliorer la croissance et la production fruitière de Z. mauritiana par l’inoculation mycorhizienne dans deux vergers au Sénégal. Il avait pour objectifs spécifiques (i) d’évaluer les réponses à l’inoculation avec des CMAs de différentes espèces de Ziziphus et de provenances de Z. mauritiana en serre, (ii) d’évaluer l’impact de l’inoculation avec R. irregularis IR27 sur la croissance, la survie et la production fruitière de Z. mauritiana, (iii) d’évaluer l’impact de l’inoculation sur la diversité des communautés de CMAs associés à Z. mauritiana en plantation et (iv) de déterminer la persistance de R. irregularis IR27 dans les racines de Z. mauritiana en plantation. Le champignon R. irregularis IR27 s’est avéré le plus efficace parmi les CMAs testés dans ce travail. Le couple Z. mauritiana /R. irregularis IR27 a donc été choisi comme modèle pour étudier l’impact de l’inoculation sur la production fruitière de deux provenances, Gola (variété indienne sélectionnée pour ses fruits de grosse taille) et Tasset (provenance locale à fruits de petite taille) dans deux sites contrastés (Amally et Keur Mangari). Nos résultats ont montré un effet positif de l’inoculation sur la croissance, la survie et le taux de mycorhization de Z. mauritiana à 13 et 24 mois respectivement à Amally et à Keur Mangari. L’inoculation a également augmenté la production fruitière des jujubiers à 18 et 30 mois de plantation à Keur Mangari. Ces résultats montrent la grande capacité de R. irregularis IR27 à compétir face aux CMAs indigènes. Le séquençage Illumina MiSeq du gène 18S a permis de révéler un impact négatif de l’inoculation sur la diversité et la richesse des communautés de CMAs natifs à Amally contrairement à Keur Mangari où l’inoculation n’a pas eu d’impact ni sur la diversité ni sur la richesse des CMAs. Le gène RPB1 s’est révélé pertinent comme marqueur pour détecter R. irregularis IR27 dans les racines de Z. mauritiana inoculés et évaluer par qPCR l’intensité de la colonisation racinaire des jujubiers par R. irregularis IR27 qui a représenté 11 à 13% à 13 mois de plantation à Amally et 12 à 15% à 24 mois de plantation à Keur Mangari. Cependant, il s’avère important d’évaluer à plus long terme l’impact de R. irregularis IR27 et son devenir dans les racines de Z. mauritiana en plantation dans une large gamme de conditions environnementales. / The jujube (or Ziziphus mauritiana Lam.) is an important multipurpose species (e.g. fruits, fodder, wood) for reforestation and fruit farming in the Sahel. In this context where soils are often degraded and deficient in P, mycorrhization and phosphorus fertilization could play a major role on improvement of jujube growth and productivity. The main objective of this work was to improve growth and fruit production of Z. mauritiana by mycorrhizal inoculation in two orchards at Senegal. This work aims (i) to evaluate the responses of different species of Ziziphus and provenances of Z. mauritiana to inoculation with AMF in greenhouse conditions, (ii) to assess the impact of inoculation with R. irregularis IR27 on growth, survival and fruit production of Z. mauritiana, (iii) to assess the impact of inoculation on diversity of native AMF communities associated to Z. mauritiana after planting and (iv) to determinate the persistence of R. irregularis IR27 in roots of Z. mauritiana after planting.The fungus R. irregularis IR27 proved to be the most effective AMF tested in this work. The pair Z. mauritiana /R. irregularis IR27 has been chosen as model to study the impact of inoculation on fruit production of two provenances, Gola (Indian variety selected for its large size fruits) and Tasset (local cultivar with small-sized fruits) in two sites with contrasting rainfall (Amally and Keur Mangari). Our results showed a positive effect of inoculation on growth, survival and mycorrhizal colonization of Z. mauritiana plants at 13 and 24 months after planting at Amally and Keur Mangari respectively. Inoculation increased also fruit production of jujubes at 18 and 30 months after planting at Keur Mangari. These results indicated the high ability of R. irregularis to compete with indigenous AMF. The MiSeq Illumina sequencing of 18S rRNA gene revealed a negative impact of inoculation on AMF richness and diversity at Amally, unlike at Keur Mangari where inoculation had no impact on AMF richness and diversity. The RPB1 gene proved to be an appropriate marker to detect of R. irregularis IR27 in inoculated Z. mauritiana roots and to evaluate by qPCR the root colonization of R. irregularis IR27 which accounted for 11 to 13% at 13 months after planting at Amally and 12 to 15% at 24 months after planting at Keur Mangari. Therefore, it is important to assess at long-term the impact of R. irregularis IR27 and its persistence in inoculated Z. mauritiana roots in large environmental conditions.