Dissertations / Theses on the topic 'Endophytes'
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Xin, Gang. "Diazotrophic endophytes of Populus /." Thesis, Connect to this title online; UW restricted, 2008. http://hdl.handle.net/1773/10104.
Full textPincebourde, Sylvain. "Biophysique environnementale des insectes endophytes." Phd thesis, Université François Rabelais - Tours, 2005. http://tel.archives-ouvertes.fr/tel-00108243.
Full textDes mesures de spectrométrie optique ont démontré que la larve modifie profondément les propriétés optiques de la surface de la feuille au cours de son nourrissage. La structure mine absorbe bien plus de radiations dans le proche infrarouge que les tissus foliaires intacts. De plus, une quantité importante de radiations est transmise à l'intérieur de la mine par le tégument supérieur dans les zones prélevées par la larve. Ces radiations induisent une élévation importante de son activité respiratoire (rejet de CO2). En utilisant un analyseur de gaz par infrarouge, nous avons pu montrer par ailleurs que les stomates localisés dans le tégument inférieur de la mine réagissent à la présence de la larve en se fermant. Un modèle de diffusion de CO2 a révélé que les stomates réagissent directement aux variations d'émission de CO2 par la larve. Le budget thermique de la mine a ensuite été modélisé. Le modèle permet de prédire la température à l'intérieur de la mine à partir des modifications des propriétés optiques et de la physiologie des stomates, et à partir des variables climatiques. Ce modèle biophysique a été validé en comparant ses prédictions avec des mesures expérimentales de température de mines réalisées en environnement contrôlé. Le modèle à une précision de 0,8 °C dans l'intervalle de 12 °C à 42 °C. Le modèle prédit un important excès de température dans la mine, atteignant 10 °C au dessus de la température de l'air et 5 °C au dessus de la température des tissus foliaires intacts. Les deux types de modifications – propriétés optiques et comportement stomatiques – ont un impact équivalent sur l'excès de température. Cette approche démontre clairement que la larve contrôle son environnement physique en modifiant son environnement. Nos résultats sont finalement discutés dans une perspective d'écologie évolutive. Plus particulièrement, le rôle du microclimat des insectes endophages dans l'évolution de leurs sensibilités thermiques et de celles de leurs parasitoïdes est détaillé.
Vandegrift, Andrew. "Ecological Roles of Fungal Endophytes." Thesis, University of Oregon, 2016. http://hdl.handle.net/1794/20401.
Full textBeau, Jeremy. "Drug Discovery from Floridian Mangrove Endophytes." Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/4287.
Full textArnold, Anne Elizabeth. "Neotropical fungal endophytes: Diversity and ecology." Diss., The University of Arizona, 2002. http://hdl.handle.net/10150/289841.
Full textWilson, Wendolyn Louise. "Isolation of endophytes from seagrasses from Bermuda." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ35540.pdf.
Full textGunson, Helen Elizabeth. "Endophytes and microbial contaminents of micropropagated plants." Thesis, University of the West of England, Bristol, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315314.
Full textPoinso, Alix. "Recherche d'inhibiteurs de la superoxyde dismutase à partir de substances naturelles." Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30378/document.
Full textSuperoxide dismutase is one of the major proteins controlling the oxidizing stress and cellular homeostasis. It is involved in numerous cancer cells proliferation processes. This protein is considered as major anti-cancer target for the development of new anti-cancer drugs. The goal of this work, was to research and identify an inhibitor of the SOD in endophytic fungi from Peruvian plants. These micro-organisms are known to produce numerous metabolites for host plants protection. During the preparation of endophytic extracts and their characterization by HPLC and statistical analyzes, we have pointed out a high quantitative and qualitative variability of the chemical content of endophytic extracts inside a same strain. Considering the literature we have focused our work on the identification of furocoumarins because of their potential inhibitory effect on the SOD. For this purpose two mass spectrometry strategies using negative ionization mode were carried out. With the QTOF mass spectrometer we have identified Methyl-4H-furo [2,3-b] [1] benzopyran-4-one and the déhydropachyrrhizone. With the OrbiTrap, the Ochrocarpine A, Moellendorffiline the Anisolactone and the Anhydrorutarétine were identified. Biological evaluation of the different extracts was performed using pyrogallol test. This investigation did not allow us to identify an inhibitor of the SOD. In the future we may consider seeking SOD inhibitors by looking at the formation SOD-chemical compound adducts using an LC-MS investigation
Reivant, Munters Arielle. "The foliar bacterial endophyte community in native Pinus radiata: a role for protection against fungal disease?" Thesis, Uppsala universitet, Institutionen för biologisk grundutbildning, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-234871.
Full textMICELI, Elisangela. "Bacterial Endophytes: Unexplored Sources Of Biotechnologically Relevant Molecules." Doctoral thesis, Università degli studi di Ferrara, 2019. http://hdl.handle.net/11392/2488023.
Full textGli endofiti sono microrganismi che colonizzano i tessuti interni delle piante senza causare nessun danno. Generalmente, gli endofiti sono in grado di compiere funzioni come la promozione della crescita della pianta e la protezione contro patogeni. Il termine olobionte indica l’insieme costituito dalla pianta e dal suo microbiota, come se questi costituissero un unico grande organismo. Nelle ultime decadi, gli endofiti sono stati sempre più studiati, poiché è diventata sempre più evidente la loro capacità di influenzare la fisiologia della pianta e la produzione di molecole bioattive. Per esempio, è stato proposto che gli endofiti possono sintetizzare composti simili a quelli sintetizzati dalla pianta ospite e che possono modulare la produzione dei metaboliti secondari della pianta. In questo contesto, gli endofiti appaiono come strumenti di grande potenziale in campo biotecnologico. Per questi motivi, abbiamo deciso di analizzare batteri endofiti da piante diverse, allo scopo di capire meglio la struttura delle loro comunità e di esplorare le loro caratteristiche fenotipiche, prospettando così una possibile applicazione in campo biotecnologico. In questo lavoro, sono state analizzati batteri endofiti da piante medicinali, da semi di piante medicinali e da piante iperaccumulatrici di sostanze tossiche. Recentemente, comunità batteriche associate alle piante medicinali Echinacea purpurea and E. angustifolia sono state analizzate nel nostro laboratorio e hanno mostrato una struttura e composizione molto specifica nei vari tessuti delle piante (foglie/stelo, radici) e nella rizosfera. Successivamente, abbiamo deciso di studiare in modo più approfondito tali comunità, concentrandoci soprattutto nei fattori che potrebbero determinare la presenza di comunità così specifiche in diversi compartimenti delle piante. Le analisi effettuate hanno mostrato che le comunità batteriche stesse potrebbero prendere parte nella strutturazione delle proprie comunità, attraverso la produzione di molecule antimicrobiche, che determinano a loro volta la colonizzazione da parte di ceppi resistenti. Inoltre, alcuni ceppi batterici estratti da Echinacea purpurea e E. angustifolia sono stati ulteriormente analizzati dal punto di vista genetico, attraverso il sequenziamento dei loro genomi. Lo studio delle sequenze ha mostrato che i ceppi endofiti presentano diversi cluster genici presumibilmente coinvolti in attività antibiotica, confermando che tali ceppi potrebbero trovare un’applicazione in campo biotecnologico. Ceppi batterici endofiti sono stati analizzati anche all’interno di semi di E. purpurea. In questo caso, oltre ad osservare la presenza di endofiti all’interno dei semi, endofiti batterici sono stati estratti dai semi e caratterizzati dal punto di vista tassonomico e fenotipico. Recentemente, la nostra analisi degli endofiti si è estesa verso le piante iperaccumulatrici. Sono stati analizzati batteri endofiti in associazione alle piante di Phragmites australis, largamente utilizzate in impianti di fitodepurazione. Questa parte del lavoro è stata possibile grazie alla collaborazione con G.I.D.A. S.p.A, Gestione Impianti Depurazione Acque. La caratterizzazione di tali endofiti ha evidenziato la loro capacità di crescita in presenza di elementi, quali ferro, boro e selenio, che sono critici nel processo di depurazione delle acque. Queste evidenze rendono possibile ipotizzare l’applicazione di tali ceppi per un incremento dell’efficienza depurativa. In conclusione, le analisi effettuate in questo lavoro di tesi hanno permesso di appronfondire le nostre conoscenze riguardo batteri endofiti provenienti da diverse fonti. Questo lavoro rappresenta, inoltre, il punto d’inizio per un possibile utilizzo di tali batteri in campo biotecnologico, al fine di rispondere a precise richieste, quali la resistenza agli antibiotici e la necessità di diminuire l’inquinamento ambientale.
Finyom, Cyprien William Bopda. "Characterisation of the endophytic bacterial communities associated with South African sorghum plants: looking for potential plant growth-promoting endophytes." Thesis, University of Western Cape, 2012. http://hdl.handle.net/11394/3431.
Full textThe term endophyte is used to define all microorganisms that, during a part of their life cycle, colonize the internal tissues of a plant host. Many endophytes have been found to promote plant growth by acting either as biocontrol agents, biofertilizers or phytohormone producers. This study aimed to characterise the endophytic microbial community diversity associated with sorghum farmed in South Africa. Members of any common endophytic bacterial species identified during the study might in future studies be developed to improve sorghum production. Sorghum tissues (roots, shoots, stems) were sampled in three South African provinces (Free State, Limpopo and North West), each site being characterised by the use of different agricultural practices. Denaturing gradient gel electrophoresis (DGGE) and terminal restriction fragment length polymorphism (T-RFLP) analyses were used to characterise the endophytic bacterial communities. The analysis clearly demonstrated that the endophytic bacterial community structure in the three sorghum tissue types differed, suggesting that endophyte colonization is tissue-specific. The endophytic bacterial community structure is quite similar in each tissue when comparing the populations present in the sampling sites. In the sorghum endophytic microbial communities, common bacterial species were identified using molecular tools: The cyanobacterium Synechococcus and Staphylococcus saprophyticus were identified in the root samples. Pantoea sp., Erwinia sp., Enterobacter sp. and Klebsiella sp. were found in all shoot samples. Nocardia fluminea, Bacillus cereus and Microbacterium sp. were isolated as common shoot endophytic bacteria. This study defines, for the first time, the endophytic bacterial species associated with South African sorghum plants. These common endophytic bacterial species can be used to enhance the yield of sorghum crops.
Al-Busaidi, Harith N. K. "Secondary metabolites from Xylaria endophytes : the isolation and structure elucidation of secondary metabolites from Xylaria endophytes by chemical and spectroscopic methods." Thesis, University of Bradford, 2011. http://hdl.handle.net/10454/5266.
Full textAl-Busaidi, Harith. "Secondary Metabolites from Xylaria Endophytes: The isolation and structure elucidation of secondary metabolites from Xylaria endophytes by chemical and spectroscopic methods." Thesis, University of Bradford, 2011. http://hdl.handle.net/10454/17479.
Full textHirst, Jevon Edward. "The ecology and physiology of endophytes of angiosperm stems." Thesis, Cardiff University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265814.
Full textWright, Jacqueline Gilda. "The role of endophytes in citrus stem end rots." Thesis, Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19736654.
Full textZhang, Dong-Xiu. "Loline alkaloid biosynthesis gene expression in epichloë endophytes of grasses." Lexington, Ky. : [University of Kentucky Libraries], 2008. http://hdl.handle.net/10225/785.
Full textTitle from document title page (viewed on May 12, 2008). Document formatted into pages; contains: xvi, 221 p. : ill. (some col.). Includes abstract and vita. Includes bibliographical references (p. 214-219).
Gordien, Andrâea Y. "Phytochemical and antimicrobial studies of Scottish plants and fungal endophytes." Thesis, University of Strathclyde, 2010. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=14347.
Full textZHANG, DONG-XIU. "LOLINE ALKALOID BIOSYNTHESIS GENE EXPRESSION IN EPICHLOE ENDOPHYTES OF GRASSES." UKnowledge, 2008. http://uknowledge.uky.edu/gradschool_diss/592.
Full textEastwood, Daniel Christopher. "Physiology of Acremonium endophytes and their interaction with Pooideae grasses." Thesis, University of Liverpool, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243230.
Full textRinkel, Barbara Elizabeth. "A molecular and morphological taxonomy of epi-/endophytes (Ulvophyceae, Chlorophyta)." Thesis, University of Bristol, 2007. http://hdl.handle.net/1983/e737a534-1eed-4d51-a7f7-954abcaeada8.
Full textCHAINTREUIL, DONGMO CLEMENCE. "Caracterisation des bradyrhizobium photosynthetiques endophytes du riz sauvage oryza breviligulata." Montpellier, ENSA, 2000. http://www.theses.fr/2000ENSA0023.
Full textBernard, Miriam. "Molecular interactions between the kelp saccharina latissima and algal endophytes." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS105.
Full textEndophytic brown algae invade stipes and fronds of kelps with potential negative effects for their hosts. The molecular diversity of kelp endophytes was investigated and a majority of the isolated endophytes belonged to the genera Laminarionema and Laminariocolax. Using a qPCR approach, a high prevalence of the endophyte Laminarionema elsbetiae was detected in natural Saccharina latissima populations, but with seasonal and geographical variations. Co-cultivation experiments showed different physiological responses of the main host, S. latissima, and an occasional host, Laminaria digitata, to L. elsbetiae. A transcriptomic approach revealed important differences between the molecular responses of the two kelps, related to the recognition of the endophyte and subsequent defence reactions. These specific differences in the molecular cross-talk during the early steps of the interaction could explain the variability of natural infection patterns in kelp species
Bulgari, D. "PHYTOPLASMAS-ENDOPHYTES INTERACTIONS: THE CASE STUDY OF GRAPEVINE YELLOWS RECOVERY." Doctoral thesis, Università degli Studi di Milano, 2010. http://hdl.handle.net/2434/150211.
Full textHundley, Nicholas James. "Structure Elucidation of Bioactive Compounds Isolated from Endophytes of Alstonia scholaris and Acmena graveolens." Diss., CLICK HERE for online access, 2005. http://contentdm.lib.byu.edu/ETD/image/etd1013.pdf.
Full textKing, Eoghan. "Caractérisation phénotypique et moléculaire de la réponse du riz au cours de l’interaction avec des espèces de Burkholderia s.l." Thesis, Montpellier, 2019. http://www.theses.fr/2019MONTG079.
Full textIn natural conditions, plants interact with a large diversity of microorganisms maintaining with them various types of interaction ranging from mutualism to pathogenesis. Whatever the type of interaction established, the plants are able to recognize conserved microbial molecular motifs which trigger a so-called “non-host” immune response when perceived. This basal immune response has been extensively studied in the case of interactions with mutualistic and pathogenic microorganisms. However, in the case of “associative symbiosis” with beneficial rhizobacteria or bacterial endophytes, grouped under the term Plant Growth-Promoting Rhizobacteria (PGPR), the immune and physiological responses of plants have been scarcely described. In this context, this thesis project aimed at describing the transcriptional regulations of the model monocotyledonous rice, in response to the interaction with beneficial -rhizospheric or endophytic- and pathogenic bacteria of the genus Burkholderia sensu lato (s.l.). This ubiquitous genus of beta-proteobacteria has the particularity of having been subdivided into two genera with distinct ecologies: the genus Paraburkholderia, which groups together environmental and plant-associated species, and the genus Burkholderia sensu stricto (s.s.), which groups together human opportunistic and pathogenic species but also phytobeneficial species such as B. vietnamiensis. RNA-Seq analysis of the transcriptomic response of rice to three endophytic strains, Paraburkholderia kururiensis M130, Burkholderia vietnamiensis TVV75 and Paraburkholderia phytofirmans PsJN, revealed contrasting physiological regulations depending on the inoculated strain; in addition, comparative analyses of root tissue colonization by these strains enabled to associate some of these regulations with different colonization patterns. Finally, the expression of genes involved in the immune response of plants, identified by the functional analysis of transcriptomes, was measured during interaction kinetics with a wider diversity of strains. For this, ten strains of Burkholderia s.l., comprising three pathogenic strains, as well as three model rice PGPR strains of the genera Azospirillum, Herbaspirillum and Pseudomonas were selected. This last approach highlighted transcriptional regulations associated with the types of colonization, rhizospheric and endophytic, or interaction, beneficial and deleterious.This work is part of the characterization of the molecular bases of plants’ response to beneficial microorganisms which represent an important potential for the development of sustainable agronomic solutions favoring nutrition and plant resistance to diseases
Meirelles, Casella Thiago. "Composés antimicrobiens ou cytotoxiques à partir de micro-organismes endophytes foliaires." Thesis, Antilles-Guyane, 2014. http://www.theses.fr/2014AGUY0836/document.
Full textBecause of the symbiotic nature of endophytes, this survey aims to investigate the probality of discovering antibacterial, antifungal and cytotoxic activities in secondary metabolites of leaf endophytes isolated from plants of Amazon and Cerrado biomes. In this study, 147 cultivable microorganisms were isolated (130 fungi, 3 bacteria and 14 unidentified or unknown microbes) from 28 plant species (4 species collected in Brazil and 24 in French Guyana). All endophytes were identified by molecular analyses of specific rDNA regions, with genomic sequencing techniques. Fungal endophytes belonging to Xylariales order were the most frequently isolated in this study, represented by 25 isolates. Crude AcOEt extracts were produced from cultures of each isolated endophyte. A significant relative proportion (23,1%) of extracts showed activity in Candida albicans ATCC 10213, while 4% were active in Staphylococcus aureus ATCC 29213. The cytotoxic potencial of the extracts was evaluated for human cell lines KB (uterin cervical carcinome), MDA-MB-435 (melanoma) and MRC-5 (normal lung fibroblasts), and a significant proportion of them showed cellular proliferation inhibition (24,4%, 23,1% e 16,3%, respectively).Eighteen secondary metabolites were isolated by the fractionation of eight endophytic extracts. Seventeen of these substances had already been previously described in the literature: piliformic acid (24) and griseofulvin (25) isolated from Xylaria cubensis SNB-GCI02; phomopiron A (26), pyrenocin A (27), alterperilenol (28) and novae-zelandin A (29) isolated from Lewia infectoria SNB-GTC2402; 5-metilmellein (31) and dihidrosporothriorid (32) isolated from Xylaria sp. SNB-GTC2501; mycoleptodiscin A (34) and mycoleptodiscin B (35) isolated from Mycoleptodiscus sp. SNB-GTC2304; mycoepoxidien (36) and altiloxin A (37) isolated from Diaporthe pseudomangiferae SNB-GSS10; acremonisol A (40), semicochliodinol A (41) and cochliodinol (42) isolated from Chaetomium globosum SNB-GTC2114; colletofragaron A2 (43) isolated from Colletotrichum sp. SNB-GTC0201; flavoglaucin (44) isolated from Eurotium rubrum BBS01. Among these substances, flavoglaucin (44), isolated from E. rubrum BBS01, showed comparable antifungal activity with the positive control fluconazol in C. albicans (MIC of 4 µg.mL-1). Flavoglaucin (44) also showed IC50 >10 µM in normal MRC-5 cells, becoming a good candidate for further studies. In this work, the cytotoxic activity of colletofragaron A2 (43), isolated from Colletotrichum sp. SNB-GTC0201 was described for the first time. The unpublished substance named pyrrocidin C (30) isolated from L. infectoria SNB-GTC2402 was identified by spectroscopic analyses (Casella et al., 2013). The pyrrocidin C (30) was active in S. aureus ATCC 10213 (MIC of 2 µg.mL-1), and was not considered cytotoxic for normal MRC-5 cells (IC50 >10 µM), showing selectivity in antimicrobial activity. These results demonstrate the great endophytic fungal diversity in plants of Amazon and Cerrado biomes, along with the chemodiversity associated to the secondary metabolites of these endophytes. Tropical fungal endophytes, like those seen in this work, may emerge as a new source of antimicrobial and cytotoxic substances
Devido à natureza simbiótica dos micro-organismos endofíticos, este estudo teve como objetivo investigar a atividade antibacteriana, antifúngica e citotóxica em metabólitos secundários de extratos de fungos endofíticos foliares de plantas do bioma Amazônia e Cerrado. Neste trabalho de tese foram isolados 147 micro-organismos cultiváveis (130 fungos, 3 bactérias e 14 fungos não-identificados ou desconhecidos) a partir de 28 plantas (4 espécies coletadas no Brasil e 24 na Guiana Francesa). Todos os micro-organismos foram identificados por análise molecular de regiões específicas de DNAr, com uso de técnicas de sequenciamento genômico. Fungos endofíticos da ordem Xylariales foram os de maior frequência de isolamento neste estudo, representados por 25 isolados. Extratos brutos em AcOEt foram produzidos a partir de culturas de cada micro-organismo isolado. Uma proporção relativa significante (23,1%) dos extratos demonstrou atividade em Candida albicans ATCC 10213, enquanto 4% foram ativos em Staphylococcus aureus ATCC 29213. O potencial citotóxico dos extratos foi avaliado para as linhagens celulares humanas KB (carcinoma cervical uterino), MDA-MB-435 (melanoma), e MRC-5 (fibroblastos de pulmão normal), resultando em proporção significante com atividade de inibição da proliferação celular (24,4%, 23,1% e 16,3%, respectivamente). Dezoito metabólitos secundários foram isolados a partir do fracionamento de oito extratos brutos endofíticos. Dezessete destas substâncias já tinham sido descritas anteriormente na literatura: ácido pilifórmico (24) e griseofulvina (25) isoladas de Xylaria cubensis SNB-GCI02; phomopirona A (26), pyrenocina A (27), alterperilenol (28) e novae-zelandina A (29) isoladas de Lewia infectoria SNB-GTC2402; 5-metilmelleina (31) e Dihidrosporothriolida (32) isoladas de Xylaria sp. SNB-GTC2501; mycoleptodiscina A (34) e mycoleptodiscina B (35) isoladas de Mycoleptodiscus sp. SNB-GTC2304; mycoepoxidieno (36) e altiloxina A (37) isoladas de Diaporthe pseudomangiferae SNB-GSS10; acremonisol A (40), semicochliodinol A (41) e cochliodinol (42) isoladas de Chaetomium globosum SNB-GTC2114; colletofragarona A2 (43) isolada de Colletotrichum sp. SNB-GTC0201; flavoglaucina (44) isolada de Eurotium rubrum BBS01. Dentre estas substâncias, a flavoglaucina (44) isolada de E. rubrum BBS01, demonstrou atividade comparável ao controle fluconazol em C. albicans (CIM de 4 µg.mL-1). Esta substância (44) apresentou IC50 >10 µM em células normais MRC-5, tornando-se candidata para estudos posteriores. Neste trabalho foi identificado pela primeira vez a atividade citotóxica da colletofragarona A2 (43), isolada de Colletotrichum sp. SNB-GTC0201. A substância inédita nomeada pyrrocidina C (30) foi isolada a partir de L. infectoria SNB-GTC2402 e identificada através de análises espectroscópicas (Casella et al., 2013). A pyrrocidina C (30) foi ativa em S. aureus ATCC 10213 (CIM de 2 µg.mL-1), e não foi considerada citotóxica para as células normais MRC-5 (IC50 >10 µM), demonstrando seletividade na ação antimicrobiana. Estes resultados demonstram a grande diversidade fúngica endofítica em plantas do bioma Amazônia e Cerrado, e a quimiodiversidade associada aos metabólitos secundários destes micro-organismos. Fungos endofíticos tropicais, como os vistos neste trabalho, podem emergir como uma nova fonte de substâncias antimicrobianas e citotóxicas
Deutscher, Tyrel Ryan. "The endophytes of Pediomelum esculentum| A unique case in legume evolution." Thesis, South Dakota State University, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10164128.
Full textPediomelum esculentum (commonly prairie turnip) is a perennial legume of the Great Plains, consisting of a deep taproot and large edible tuber, and has served as a nutritious staple in Native American diets. The tuber is capable of storing up to 20 percent protein by weight. P. esculentum is a legume, but not a prominent nodule former; instead, it grows in nitrogen-limited soils and produces large amounts of protein. This suggests the involvement of biological nitrogen fixation. We have investigated the presence of diazotrophic endophytes in P. esculentum. Bacteria were isolated from wild plants on nitrogen free media, identified with their partial 16S rRNA gene sequences, and screened for the presence of the nitrogen fixation gene nifH. Select isolates were applied as a co-inoculum to seedlings grown under gnotobiotic conditions in a growth chamber with no nitrogen source. Seedlings in both the inoculated and uninoculated group developed nodules and showed no signs of nitrogen stress. Bacteria isolated from the nodules and tubers of both groups were closely related to the same Bacillus bacterium isolated from seeds germinated under sterile conditions, according to partial 16S rRNA sequences. Bright field and fluorescence imaging revealed bacteria present in the intercellular space of four-week-old tubers and in the sterile germinated seeds. Sectioning and imaging of the nodules show a central nodule vasculature and infected cells extending inwards to the main root vasculature. Nitrogen fixation in the plants was indirectly confirmed by acetylene reduction. Our results suggest P. esculentum has formed a unique symbiosis with a nitrogen fixing Bacillus bacterium that transmits vertically in the seeds and induces nodules.
Wu, Ruomou. "Identification of candidate plant growth promoting endophytes from Echium plantagineum roots." University of the Western Cape, 2018. http://hdl.handle.net/11394/6288.
Full textThe yearly increase of global population will result in a greater demand for crop production, but with the climates changes and a lack of available agricultural land it will become increasingly more difficult to provide sufficient crops to feed everyone adequately. Application of the PGPE has proven over the past researches to be able enhance growth of plants via various growth promoting mechanisms. To identify suitable growth promoting bacteria candidate, E. plantagineum plant was used to isolate endophytes from the root after surface sterilization. The isolates bacteria were used to inoculate Brassica napus L seeds. The effects of isolate's ability to promote growth were evaluated based on the certain growth parameters after 42 days in the green house. Isolate CP5 produced highest results in all growth parameter. Isolates CP5 was selected as potential candidate as significant improvement was shown by this isolate. This isolate was tested for the ability to produce ACC deaminase, solubilize phosphate, synthesize IAA and siderophore production. Furthermore isolate CP5 growth promotion abilities was tested on Brassica napus L under antimony stress.
2021-08-31
Pérez, Hemphill Catalina Francis [Verfasser]. "Bioactive fungal natural products from extremophilic endophytes / Catalina Francis Pérez Hemphill." Düsseldorf : Universitäts- und Landesbibliothek der Heinrich-Heine-Universität Düsseldorf, 2017. http://d-nb.info/1125595418/34.
Full textBailes, Graham. "Drivers of endophyte communities in Pacific Northwest prairies." Thesis, University of Oregon, 2017. http://hdl.handle.net/1794/22783.
Full textMattila, née Pirttilä A. M. (Anna Maria). "Endophytes in the buds of Scots pine (Pinus sylvestris L.)." Doctoral thesis, University of Oulu, 2001. http://urn.fi/urn:isbn:9514264444.
Full textGillanders, Timothy James. "The development of new inoculation techniques and viability tests for Neotyphodium endophytes." Thesis, University of Canterbury. Biological Sciences, 2007. http://hdl.handle.net/10092/3677.
Full textGagné-Bourque, François. "The isolation, identification and characterization of endophytes of the bioenergy crop switchgrass." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=106473.
Full textLe panic érigé (Panicum vergatum L.) est reconnu comme une des plantes modèles pour la production de biomasse végétale. Il est connu que la plupart des plantes vasculaires étudiées à ce jour sont colonisées par des champignons et bactéries endophyte. Cette étude avait pour but d'explorer les communautés d'endophytes présentes dans différents cultivars de panic érigé au Québec, pour ensuite isoler les endophytes et effectuer leur identification taxonomique en comparant leur séquence ITS rADN. Nous avons obtenu un total de 145 isolats (52 bactéries et 93 champignons) venant de feuille de plante au stade végétative et au stade reproductive. Une fois les isolats identifiés, nous avons obtenu cinq différents groupes taxonomiques pour les bactéries et neuf pour les champignons. Nous avons évalué le potentiel antifongique des différents endophytes bactériens, avec pour objectif d'identifier les candidats potentiels à la ré-inoculation de cultivar de panic érigé commercial afin augmenter leur production de biomasse. À l'aide de séquences d'amorces spécifiques, nous avons pu démontrer la transmission verticale des endophytes.
Florea, Simona. "TOWARDS ELIMINATION AND GENETIC MANIPULATION OF ERGOT ALKALOID PRODUCTION IN FUNGAL ENDOPHYTES." UKnowledge, 2009. http://uknowledge.uky.edu/gradschool_diss/803.
Full textUpson, Rebecca. "The status of dark septate root fungal endophytes in Antarctic plant communities." Thesis, University of Sheffield, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.434597.
Full textRAVEL, CATHERINE. "Les champignons endophytes des graminees : distribution et coevolution avec leurs especes hotes." Clermont-Ferrand 2, 1997. http://www.theses.fr/1997CLF21937.
Full textNAFFAA, WALID. "Les champignons endophytes des graminees : variabilite et co-adaptation avec leurs-hotes." Clermont-Ferrand 2, 1998. http://www.theses.fr/1998CLF21999.
Full textHan, Jianying. "Exploring the Potential of Endophytes and Fungi as Sources of Antimicrobial Compounds." Thesis, Griffith University, 2021. http://hdl.handle.net/10072/404851.
Full textThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Environment and Sc
Science, Environment, Engineering and Technology
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Pillay, Kerry-Anne. "Diversity and spatial distribution of fungal endophytes in a Eucalyptus grandis tree." Diss., University of Pretoria, 2012. http://hdl.handle.net/2263/31514.
Full textDissertation (MSc)--University of Pretoria, 2012.
Genetics
MSc
Unrestricted
Moloinyane, Siphokazi. "Bioefficacy of selected entomopathogenic fungal endophytes (Ascomycota) against grapevine mealybug (Planococcus ficus)." Thesis, Cape Peninsula University of Technology, 2018. http://hdl.handle.net/20.500.11838/2858.
Full textGlobal demand for environmentally-friendly grapevine cultivation and pest control has necessitated an improved understanding of the relationship between soil properties and beneficial naturally occurring antagonists like entomopathogenic fungi (EPF). This group of fungi presents a viable alternative for the control of destructive pests such as the grapevine mealybug. Sixty-six soil samples were collected from 22 vineyards in the Western Cape, South Africa. The association between soil nutrient status and EPF prevalence was then examined. Fungi were isolated with methods of insect baiting and selective media. Fungal strains were identified and characterized using light microscopy and DNA analysis (ITS and BTub). In addition, fungal isolates were tested against a key grapevine pest, Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae) using an immersion bioassay at a concentration of 1 x 108 conidia ml-1. Twenty-three fungal strains were isolated and correspondence analysis (CA) of data indicated a positive association between fungal occurrence and moderate to high levels of soil-based macronutrients. Binomial logistic regression analysis revealed that soil N, K, Ca, Mg and S concentrations and C/N ratio were correlated with at least one EPF species. This study showed that some soil nutrient properties correspond to greater occurrence of EPF in grapevine soils. Strains of Beauvaria bassiana (Hypocreales: Clavicipitaceae) caused the highest mortalities (82% to 87%). In chapter three, I examined the effect of B. bassiana inoculation of grape plants on the infestation level of P. ficus, and the growth and volatile constituents of potted grape plants. The grapevines were inoculated with 1 x 108 conidia ml-1 of B. bassiana by drenching before experimentally infesting them with thirty P. ficus adult females. At four weeks post treatments, the fungus was re-isolated from leaves of 50% of the fungus exposed plants. No significant difference (P > 0.05) was observed in all the plant growth parameters measured in the fungus treated and control plants. Plant tissue analysis revealed markedly higher contents of Ca and Mg in leaf tissue of plants exposed to the B. bassiana relative to the control. GC-MS analyses showed that a significantly (X2=5.1; P<0.02) higher number of known anti-insect volatile compounds (9) including napthtalene were present among fungus treated plants compared to the control plants (5). However, B. bassiana did not have any significant effect on total polyphenol, alkaloid and flavonoids. Overall, treatment with fungus did not offer any protection against infestation of P. ficus. In conclusion, this is the first study to report on the isolation of indigenous entomopathogenic fungal (EPF) strains within vineyards of the Western Cape. The study revealed that inoculating grapevine plants during cultivation had a net positive effect on the production of volatile compounds in grapevines. These findings shed light on the mechanisms involved in endophytic fungus-plant-insect interactions. This study contributes valuable information to future development of ecological approaches involving EPF for insect control in vineyards and in general, agricultural settings.
Munakata, Yuka. "Study of interactions of plants and endophytic microorganisms for characterizing active molecules for biocontrol and pharmaceutical applications." Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0317.
Full textSince the mid-21st century, the use of synthetic chemistry has provided a range of effective solutions for plant health (pesticides) and human health (medicines). However, the widespread use of some of these solutions has raised concerns for the environment and for human health and has led to the selection of resistant populations of pathogens. These effects call into question the use of these solutions to control plant and human pathogens. It is, therefore, necessary to identify innovative and more sustainable solutions for crop protection and drug development. One strategy is to explore new biological resources such as microbial resources.My thesis focused on bacteria that realize part of their life cycle in plant tissues and are called endophytic bacteria. These micro-organisms have interesting potential for the development of biocontrol solutions for agriculture and for the production of pharmaceutical drugs. In the two first chapters of this thesis, I explored the taxonomic and functional diversity of the endophytic communities of two plant species with remarkable properties, Chrysopogon zizanioides, and Leucojum aestivum, using metabarcoding approaches and/or isolation of bacterial strains. In particular, I have established strain libraries whose activities against wheat pathogenic fungi and, in particular, against Fusarium graminearum have been analyzed. Some strains affiliated to the genera Bacillus, Serratia, Janthinobacterium, or Streptomyces showed excellent inhibition of the mycelial growth of the plant pathogen in in vitro co-culture. Specialized metabolites produced by these strains were also studied, targeting two groups of molecules known for their antimicrobial activities or their therapeutic interest, alkaloids, and lipopeptides. Thus, a precursor of indole alkaloids was identified in two bacterial strains isolated from L. aestivum. Lipopeptides, already known for their antimicrobial activities, were also identified in Bacillus subtilis strains isolated from vetiver roots.Both approaches led to the identification of numerous strains but only a few interesting candidates. In the third chapter, I investigated an innovative strategy to easier target microorganisms of interest, and I focused on the protection of wheat against F. graminearum. The preliminary results provided a fundamental part to test the concept of the host-mediated engineering of soil and endosphere microbiota toward a resistant microbial community, leading to more efficient isolation of functional endophytes.This work, by exploring the endophyte diversity associated with plants with particular properties, provides very rich biological material that might be used as biocontrol solutions or for the production of bioactive compounds
BRANNOCK, JILL MARIE. "CHARACTERIZATION OF ROOT ENDOPHYTIC BACTERIA." University of Cincinnati / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1100806990.
Full textMurúa, Pedro. "Molecular and cell biology of novel brown algal pathosystems." Thesis, University of Aberdeen, 2018. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=238693.
Full textMcAlpine, Jesse. "The Role of Yeasts in the Pollination Success of a Neotropical Orchid." Thesis, University of Oregon, 2013. http://hdl.handle.net/1794/13280.
Full textBarthélémy, Morgane. "Etude de la diversité chimique et biologique d’endophytes de palmiers." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS563.
Full textThe palm Astrocaryum sciophilum is the host plant model chosen in this work. Indeed, due to the longevity of its leaves, we expected to highlight a competitive community of endophytes within the oldest leaves. Thus, 197 endophytes have been isolated and identified from different leaves of six palm specimens. In order to evaluate whether the compounds produced by these microorganisms could be used for the treatment of human disease, the ethyl acetate extracts of each endophyte were tested against methicillin-resistant Staphylococcus aureus (MRSA) as well as for a quorum quenching (QQ) activity. Simultaneously, co-culture were carried with the fungi Fusarium oxysporum in order to highlight endophytes providing plant protection against phytopathogens. We selected extracts in order to isolate and identify the bioactive metabolites. Various analytical tools have been used to improve the isolation process (LC-MS/MS, molecular networking or MS imaging).The study of the endophytic community isolated from older leaves did not show a more competitive chemical arsenal. However, two Luteibacter strains exhibited an ethyl acetate extract active against MRSA and several bacteria provide quorum quenching extracts. The metabolome of Colletotrichum genus was studied using molecular networking and a fungus from the Xylariaceae family was studied for its capacity to inhibit F. oxysporum’s growth. In our study, seven endophyte strains were chemically investigated leading to the isolation and identification of 42 molecules whose ten are new
Khiralla, Afra. "Études phytochimique, cytotoxique et antibactérienne de champignons endophytes issus de plantes médicinales du Soudan." Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0159/document.
Full textThis study investigated, for the first time, the endophytic fungi flora of five Sudanese medicinal plants: Calotropis procera (Ait.), Catharanthus roseus (L.), Euphorbia prostrata (Ait.), Trigonella foenum-graecum (L.) and Vernonia amygdalina (Del.). A total of 23 endophytic fungal strains were isolated from the plants after surface disinfection and different biological tests were performed. Total phenolic content (TPC) and total antioxidant activity of ethyl acetate crude extracts of 21 endophytes and their host plants were estimated using respectively the Folin-Ciocalteu colorimetric method and 1,1,-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging in vitro method. General evaluation of the cytotoxicity of 16 selected endophytes and their host plants was performed by the MTT assay using cancer cells type: Human breast carcinoma (MCF7) and Colon adenocarcinoma (HT29 and HCT116). Preliminary antibacterial screening was done for the 16 endophytes. These extracts were also tested against two representative bacterial strains, Escherichia coli and methicillin-resistant Staphylococcus aureus, by broth dilution tests. The endophyte, Aspergillus terreus 1 from T. foenum-graecum seeds had the highest TPC in term of Gallic Acid Equivalent (89.9 ± 7.1 mg GAE/g) and antioxidant activity (IC50: 18±0.1µg/mL). Byssochlamys spectabilis showed strong cytotoxicity (1.51 ± 0.2 µg/mL) followed by Cladosporium cladosporioides 2 (10.5 ± 1.5 µg/mL), then Alternaria sp. (13.5 ± 1.8 µg/mL). Only six strains showed activity against methicillin-resistant S. aureus with MIC values ranging between 0.125-2 mg/mL, Alternaria alternata (0.125 mg/mL) Alternaria sp. (0.250 mg/mL) and Byssochlamys spectabilis values (0.5 mg/mL). Ten pure compounds (0.3 to 40 mg) were isolated from ethyl acetate crude extract of Curvularia papendorfii .The new pure compound (AFB) 3,7,11,15-Tetrahydroxy-18-hydroxymethyl-14,16,20,22,24-pentamethyl-hexacosa-4E,8E,12E,16,18-pentaenoic acid (Khartoumic acid) revealed moderate antibacterial activity against S. aureus with MIC value 62.5 µg/mL and weak cytotoxicity with a IC50 > 100 µM against MCF7 cells. The pure compound AF1 showed moderate cytotoxic activity with IC50 value of 29.78 µM against HT29 and weak antibacterial activity with MIC 250 µg/mL against S. aureus. Both compounds displayed no antioxidant activity
Muvea, Alexander Mutua [Verfasser]. "The effect of fungal endophytes on thrips and tospovirus epidemiology / Alexander Mutua Muvea." Hannover : Technische Informationsbibliothek und Universitätsbibliothek Hannover (TIB), 2015. http://d-nb.info/1074259831/34.
Full textPham, Ngoc Tuan [Verfasser]. "Micropropagation and identification of bacterial endophytes in interspecific hybrid walnuts / Ngoc Tuan Pham." Hannover : Technische Informationsbibliothek (TIB), 2017. http://d-nb.info/1149830557/34.
Full textKamal, Nurkhalida. "Isolation and characterisation of bioactive compounds from Vitex pinnata and associated fungal endophytes." Thesis, University of Strathclyde, 2015. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=25909.
Full textDel, Olmo Ruiz Mariana. "Diversity, Distributions, and Host Affiliations of Fungal Endophytes Associated with Seedless Vascular Plants." Diss., The University of Arizona, 2012. http://hdl.handle.net/10150/243097.
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