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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Cuticle-degrading proteases of Metarhizium anisopliae : enzyme regulation and gene cloning

Paterson, Ian Charles January 1992 (has links)
No description available.
2

The effect of introduced Pseudomonas fluorescens strains on nitrogen dynamics in the rhizosphere of crop plants

Brimecombe, Melissa Jane January 1999 (has links)
The primary aim of this study was to investigate the effects of seed inoculation with the biocontrol agent Pseudomonas fluorescens strain F113 (producing the antibiotic DAPG) and its modified derivative strain F113G22 (with DAPG production disrupted) on the uptake of nitrogen by pea and wheat plants. Uptake of N by the two plant species was investigated in soil microcosms amended with 15N-labelled fertilisers (urea or ammonium nitrate) or 15N-labelled plant residues. Uptake of fertiliser-N was unaffected by inoculation. However, uptake of N derived from organic residues was enhanced in pea inoculated with either strain. In contrast, uptake of N by wheat was reduced in the presence of either strain F113 or F113G22, suggesting that the effects of these microbial inocula on N-mineralisation in the rhizosphere were dependent on plant species. It was subsequently found that microfaunal populations, especially soil nematodes in the rhizosphere of inoculated pea were significantly larger than those associated with the rhizosphere of non-inoculated controls. In wheat, however, microfaunal populations in the rhizosphere of inoculated plants were lower than those associated with noninoculated controls. These trends were repeated using simple sand microcosms into which soil bacteria and the bacterial-feeding nematode Caenorhabditis elegans were introduced. This suggested that effects on N-mineralisation were mediated by changes in populations of microbial-feeding microfauna. As a possible explanation for the increased nematode populations in the rhizosphere of inoculated pea plants, the nematicidal effects of pea seed exudates on C. elegans were investigated in small-scale sand systems. It was found that exposure to non-inoculated pea seeds reduced the short-term survival of C. elegans as compared to unamended sand, and that survival was greater in the presence of pea seeds inoculated with either strain than non-inoculated seeds, suggesting that nematicidal compounds released by germinating pea seeds were utilised by the P.fluorescens strains. No such effects were observed for wheat.
3

The physiological regulation of secondary metabolite production in a microbial culture with biocontrol activity

Smith, Jonathan January 1996 (has links)
Antibiotic production kinetics of Streptomyces strain JS1 (an isolate selected from an industrial screen for biocontrol activity) and Streptomyces hygroscopicus (a culture collection strain with similar biocontrol activity to JS1) were examined. Growth-associated niphimycin production was observed in both strains during carbon-limited batch culture. Growth associated antibiotic production in carbon-limited medium has not been reported elsewhere and the antibiotic production physiology of biocontrol isolates has not been extensively studied in other laboratories. Increases in biomass and antibiotic production occurred simultaneously in JS1 (24h) and S. hygroscopicus (40h) carbon-limited cultures. Specific growth and antibiotic production rates peaked simultaneously (35h in S. hygroscopicus, 30h in JS1). Examination of the correlation between intracellular protein synthesis rate and niphimycin production rate was consistent with the relationship between these parameters proposed (in our laboratory and elsewhere) for the more frequently reported phenomenon of growth- dissociated antibiotic production. Evidence was obtained which resulted in a hypothesis that the unusual antibiotic production kinetics were a result of the unusually low affinity of JS1 for glucose. A novel approach (multi-compartment nonlinear modelling) to the determination of substrate affinity constants yielded a Ks value of 2.9mM which compares to 7.55muM (i.e. significantly higher affinity) value for Saccharopolyspora erythraea, a species which demonstrates the more common, growth dissociated form of production. Antibiotic production in nitrogen-limited culture was also growth- associated, but this has been reported elsewhere. Work reported here suggests that affinity for nitrogen substrate is significantly lower than that for glucose in S. erythraea (4.45mM compared to 7.55muM) a strain that also exhibits growth-associated antibiotic production under nitrogen limitation. This presumably explains the more growth-associated production kinetics observed in nitrogen-limited cultures. It is tempting to speculate a link between antibiotic production kinetics and biocontrol potential. A micro-organism capable of releasing anti-microbial product in synchrony with cell growth would presumably have more effect in reducing the rhizosphere microflora, prior to colonising the habitat, than a species producing the antibiotic as a secondary metabolite. If this hypothesis is justified, then it may explain the success of JS1 and S. hygroscopicus in the industrial screen. A mutant of JS1, unable to produce niphimycin, displayed diminished biocontrol capability, indicating that niphimycin has a role in the observed biological control effect, in this instance. An attempt to increase the biocontrol effectiveness of JS1 by enhancing niphimycin production in hydroponic and agar tomato culture systems was unsuccessful due to the production kinetics displayed by JS1. Manipulating culture conditions for increased niphimycin production inevitably resulted in increased JS1 growth which was associated with plant death. Electron microscopy suggested that this enhanced growth resulted in excessive colonisation of the root system, possibly resulting in plant death due to root oxygen starvation. The fungal pathogens Phytophthora capsici and Fusarium oxysporum, used as challenge organisms in the industrial screen, had significantly higher affinities for the substrates examined (15muM and < 10muM, respectively for glucose and 22muM and < 38muM, respectively, for nitrate) compared to the affinities of JS1 (2.9mM and 2.4mM, respectively, for glucose and nitrate) indicating that competition for nutrients was unlikely to account for the success of JS1 in the screen. An additional novel concept explored in this work was the use of a fractional factorial medium design procedure (the Plackett-Burman technique) for the attempted identification of nutrients that could be used to simultaneously enhance growth of biocontrol agents whilst inhibiting the growth of target pathogens. Nutritional requirements thus elucidated were compared to those of variant strains of S. hygroscopicus and other Streptomyces species.
4

Antagonism of phytopathogenic fungi by Pythium oligandrum Drechsler

Holmes, Keith Andrew January 1997 (has links)
No description available.
5

Ecological approaches to selective isolation of actinomycetes for bioactivity screening

Upton, Mathew January 1994 (has links)
No description available.
6

Biocontrol Agents and Plant Inoculants: Implications for Strengthening the BTWC

Whitby, Simon M. January 2005 (has links)
Yes
7

Rhizomodulation for tomato growth promotion and management of root knot nematodes using Pochonia chlamydosporia and chitosan

Escudero Benito, Nuria 13 November 2015 (has links)
No description available.
8

Biološka aktivnost i hemijski sastav ekstrakata odabranih autohtonih makrogljiva / Biological activity and chemical caracteristics  of selected extracts of  autochtonous macrofungi

Janjušević Ljiljana 18 September 2017 (has links)
<p>Prema postavljenim ciljevima u ovoj doktorskoj disertaciji sakupljeno je i&nbsp;<br />determinisano&nbsp;ukupno&nbsp;sedam&nbsp;vrsta&nbsp;autohtonih&nbsp;gljiva&nbsp;sa&nbsp;područja&nbsp;Fru&scaron;ke&nbsp;gore, Tare i&nbsp; Vr&scaron;ačkog brega, pet lignikolnih&nbsp;‐&nbsp;<em>Bjerkandera adusta</em>,&nbsp;<em>Pleurocybella&nbsp; porrigens</em>,&nbsp;St<em>ereum&nbsp;hirsutum,&nbsp;Stereum&nbsp;subtomentosum</em>&nbsp;i&nbsp;Trametes&nbsp;versicolor,&nbsp;i&nbsp;<br />dve&nbsp; terikolne&nbsp;‐&nbsp;<em>Amanita&nbsp; strobiliformis</em>&nbsp;i Hydnum repandum. Utvrđena je&nbsp; njihova&nbsp;biolo&scaron;ka&nbsp;aktivnost&nbsp;(antiradikalska,&nbsp;antioksidativna,&nbsp;antimikrobna,&nbsp;anti‐acetilholinesterazna&nbsp;i&nbsp;citotokisčna)&nbsp;spram&nbsp;hemijskog&nbsp;sastava&nbsp;njihovih&nbsp;vodenih&nbsp;<br />(H<sub>2</sub>O),&nbsp;etanolnih&nbsp;(EtOH),&nbsp;metanolnih&nbsp;(MeOH)&nbsp;i&nbsp;polisaharidnih&nbsp;(PSH)&nbsp;ekstrakata.&nbsp;<br />Analiza&nbsp;hemijskog&nbsp;sastava&nbsp;odabranih&nbsp;vrsta&nbsp;uključila&nbsp;je&nbsp;određivanje&nbsp;hemijske&nbsp;<br />karakterizacije&nbsp;PSH&nbsp;ekstrakata&nbsp;‐&nbsp;FTIR&nbsp;analizom,&nbsp;određivanje&nbsp;fenolnog&nbsp;profila&nbsp;‐&nbsp;<br />HPMC/MS‐MS,&nbsp;sadržaja&nbsp;organskih&nbsp;kiselina&nbsp;‐&nbsp;HPLC,&nbsp;sadržaja&nbsp;masnih&nbsp;kiselina&nbsp;‐&nbsp;<br />GC‐FID&nbsp;i&nbsp;sadržaja&nbsp;biogenih&nbsp;elemenata&nbsp;‐&nbsp;AAS.&nbsp;Spektrofotometrijskim&nbsp;metodama<br />određen je ukupan sadržaj proteina i ukupan sadržaj fenola i flavonoida.&nbsp;<br />Prema&nbsp;antiradikalskoj&nbsp;aktivnosti&nbsp;OH<sup>&bull; ,&nbsp;</sup>O2<sup>&bull;‐</sup>,&nbsp;OH<sup>&bull;</sup>,&nbsp;Asc<sup>&bull;</sup>,&nbsp;DPPH<sup>&bull;&nbsp;</sup> i&nbsp;ABTS<sup>&bull;+</sup>&nbsp;izdvojili&nbsp;<br />su&nbsp; se&nbsp; ekstrakti lignikolnih vrsta:&nbsp; MeOH ekstrakt vrste&nbsp;<em>P. porrigens</em>, H<sub>2</sub>O&nbsp; ekstrakt&nbsp;<em>P.&nbsp;porrigens</em>,&nbsp;MeOH&nbsp;ekstrakt&nbsp;<em>T.&nbsp;versicolor</em>,&nbsp;H<sub>2</sub>O&nbsp;ekstrakt&nbsp;<em>S.&nbsp;hirsutum, </em>MeOH&nbsp;ekstrakt&nbsp;<em>S.&nbsp;subtomentosum</em>&nbsp;i&nbsp;H<sub>2</sub>O&nbsp;ekstrakt&nbsp;<em>B.&nbsp;adusta</em>,&nbsp;navedenim&nbsp;redom.&nbsp;<br />Najjaču antioksidativnu aktivnost dobijenu FRAP i polarografskom HPMC&nbsp;<br />metodom ispoljili su PSH i H<sub>2</sub>O ekstrakti terikolne vrste&nbsp;<em>A. strobiliformis</em>.&nbsp;<br />Antimikrobna aktivnost analiziranih ekstrakata određena je ispitivanjem&nbsp;<br />antibakterijskog,&nbsp;antifungalnog&nbsp;i&nbsp;antiviralnog&nbsp;potencijala,&nbsp;pri&nbsp;čemu&nbsp;se&nbsp;izdvojila&nbsp;<br />vrsta&nbsp;<em> H.&nbsp; repandum</em>&nbsp;ispoljavajući najbolji efekat na Gram‐pozitivne i Gram‐<br />negativne bakterije i na sve analizirane fitopatogene izolate&nbsp;<em>(Fusarium&nbsp;</em>i&nbsp;<br />Alternaria)&nbsp;i<em>&nbsp;T.&nbsp;versicolor</em>&nbsp;na&nbsp;analizirani&nbsp;bakteriofag.&nbsp;Anti‐acetilholinesterazna&nbsp;<br />aktivnost određena je testovima in solid i in liquid, a najbolji procenat&nbsp;<br />inhibicije AChE ispoljili su EtOH ekstrakti vrsta&nbsp;<em>S. hirsutum</em>,&nbsp;<em>B. adusta</em>,&nbsp;<em>S</em>.&nbsp;<br /><em>subtomentosum</em>&nbsp;i&nbsp;<em>T.&nbsp;versicolor</em>.&nbsp;Citotoksična&nbsp;aktivnost&nbsp;ekstrakata&nbsp;određena&nbsp;je&nbsp;<br />MTT testom, a prema najboljoj ispoljenoj aktivnosti izdvojili su se MeOH&nbsp;<br />ekstrakt<em>&nbsp;P.&nbsp;porrigens&nbsp;</em>i&nbsp;ekstrakti<em>&nbsp;B.&nbsp;adusta</em>,&nbsp;H<sub>2</sub>O&nbsp;i&nbsp;EtOH.&nbsp;Citotoksična&nbsp;aktivnost&nbsp;<br />ovih&nbsp;lignikolnih&nbsp;vrsta&nbsp;naročito&nbsp;je&nbsp;izražena&nbsp;nakon&nbsp;72&nbsp;h.&nbsp;Na&nbsp;osnovu&nbsp;dobijenih&nbsp;<br />rezultata, gde su se istakle različite vrste i njihovi različiti ekstrakti u&nbsp;<br />primenjenim&nbsp;testovima,&nbsp;jasno&nbsp;je&nbsp;da&nbsp;biolo&scaron;ka&nbsp;aktivnost&nbsp;i&nbsp;hemijski&nbsp;sastav&nbsp;zavise&nbsp;<br />od&nbsp;porekla,&nbsp;vrste&nbsp;i&nbsp;tipa&nbsp;ekstrakta&nbsp;analiziranih&nbsp;gljiva.&nbsp;Na&nbsp;osnovu&nbsp;tipa&nbsp;rastvarača&nbsp;<br />odnosno ekstrakata vrsta, koje su pokazale najbolju aktivnost spram pomenutih&nbsp; testova i na osnovu dobijenih korelacija kao i na osnovu detektovanih jedinjenja,&nbsp; pretpostavljamo da su za ispoljene aktivnosti u najvećoj meri odgovorna fenolna&nbsp; jedinjenja&nbsp;i&nbsp;polisaharidi.&nbsp;&nbsp;<br />&nbsp;<br />Ispoljeni&nbsp;biopotencijal&nbsp;analiziranih&nbsp;vrsta&nbsp;gljiva&nbsp;upućuje&nbsp;na&nbsp;njihovu&nbsp;potencijalnu&nbsp;<br />upotrebu kao funkcionalne hrane i nutraceutika, kao i u biokontroli&nbsp;<br />fitopatogena.</p> / <p>According&nbsp; to&nbsp; the&nbsp; set&nbsp; aims&nbsp; of&nbsp; the&nbsp; presented&nbsp; PhD&nbsp; thesis,&nbsp; seven&nbsp; autochthonous fungal species from the region of Fruska Gora, Tara&nbsp; and Vr&scaron;ac Mountains were collected and determined: five lignicolous ‐ <em>Bjerkandera&nbsp; adusta,&nbsp; Pleurocybella&nbsp; porrigens,&nbsp; Stereum&nbsp; hirsutum,&nbsp; Stereum subtomentosum and Trametes versicolor</em>, and two terricolous ‐ <em>Amanita strobiliformis </em>and <em>Hydnum repandum</em>. Biological activity of these&nbsp; species&nbsp; (antiradical,&nbsp; antioxidant,&nbsp; antimicrobial,&nbsp; anti‐ acetylcholinesterase and cytotoxic) was determined in relation to the chemical composition of the extracts, aqueous (H<sub>2</sub>O), ethanolic (EtOH), methanolic (MeOH) and polysaccharide (PSH). Analysis of the chemical content of analyzed species included chemical characterization of PSH extracts&nbsp; &ndash;&nbsp; by&nbsp; FTIR&nbsp; analysis,&nbsp; determination&nbsp; of&nbsp; phenolic&nbsp; profile ‐ by HPMC/MS‐MS, content of organic acids ‐ by HPLC, fatty acid content ‐ by&nbsp; GC‐FID&nbsp; and&nbsp; content&nbsp; of&nbsp; biogenic&nbsp; elements ‐ by&nbsp; AAS. Spectrophotometric methods were applied for determination of the content of total proteins, polyphenols and flavonoids. According to the antiradical activity obtained towards OH<sup>&bull;</sup>, О2<sup>&bull;‐</sup>, OH<sup>&bull;</sup>, Asc<sup>&bull;</sup>, DPPH<sup>&bull;</sup>&nbsp;and ABTS<sup>&bull;+</sup> extracts of lignicolous species were singled out: <em>P. porrigens&nbsp;</em> (MeOH&nbsp; extract),&nbsp;<em> P.&nbsp; porrigens</em>&nbsp; (H<sub>2</sub>O&nbsp; extract),&nbsp;<em>T. versicolor</em>&nbsp;(MeOH&nbsp;&nbsp; extract),<em> S. hirsutum </em>(H<sub>2</sub>O extract), <em>S. subtomentosum</em> (MeOH extract) and&nbsp;<em>B. austa</em> (H<sub>2</sub>O&nbsp; extract),&nbsp; respectively. The&nbsp; highest antioxidant activity obtained by FRAP and the polarographic HPMC method was exhibited&nbsp; for PSH&nbsp; and&nbsp; H<sub>2</sub>O extracts of the terricolous species&nbsp;<em>A. strobiliformis</em>. The intimicrobial activity of analyzed extracts was determined by examination of antibacterial, antifungal and antiviral potentials, whereby&nbsp; the species&nbsp; <em>H.&nbsp; repandum&nbsp;</em>was separated by exhibiting the best effect on Gram‐positive&nbsp; and Gram‐negative bacteria, and all the analyzed hytopathogenic isolates (<em>Fusarium, Alternaria</em>)&nbsp; and <em>T. versicolor</em>&nbsp;against analyzed bacteriophage. Anti‐cetylcholinesterase activity was determined by tests in solid and in liquid, while the best&nbsp; percent of AChE inhibition was showed by EtOH extracts of the species <em>S. hirsutum, B. adusta, S. subtomentosum </em>and <em>T. versicolor</em>.bThe cytotoxic activity of extracts was determined by MTT assay, and according to the best activity, the MeOH extract of <em>P. porrigens</em>, and H<sub>2</sub>O and EtOH extracts of <em>B. adusta</em>&nbsp;were distinguished particularly after 72 h. Based on the results obtained, favoring different species and their different extracts in the applied tests, it is clear that the biological activity and chemical composition depend on the origin, species and type of extract of the analyzed fungi. Based on the type of solvent or extract of the species that showed the best activity in relation to the above tests and on the basis of the obtained correlations as well as on&nbsp; the basis of the detected compounds, we assume&nbsp; that&nbsp; the&nbsp; phenol compounds&nbsp; and&nbsp; polysaccharides&nbsp; are responsible for the activities performed.<br />Demonstrated bio‐potential of analyzed fungal species indicates their&nbsp; potential use as functional foods and nutraceutics, as well as in the biocontrol of phytopathogens.</p>
9

Sustainable Management of Grapevine Trunk Diseases in Vineyard: Deliver Biocontrol Agents and Associated Molecules

Cunha Maia Leal, Catarina Da 12 January 2023 (has links)
[ES] Las plantas de vid (Vitis vinifera L.) están expuestas a una gran variedad de patógenos. En la actualidad, las enfermedades fúngicas de la madera de la vid (GTDs) se encuentran entre los principales factores que limitan la productividad de este cultivo. Una vez las vides están infectadas, la productividad de la planta disminuye, provocando una muerte lenta o apoplética. La investigación de agentes de control biológico (BCAs) capaces de prevenir, o al menos minimizar, el impacto de las GTDs, se considera una prioridad de investigación. En esta Tesis Doctoral se caracterizó un agente de biocontrol potencial y, junto con un producto comercial biológico ya registrado, fueron probados contra varios patógenos agentes causales de GTDs, en invernadero bajo condiciones controladas, y también durante el proceso de propagación de la vid en vivero. Los resultados del análisis genómico completo de Bacillus subtilis PTA-271 muestran un sistema funcional de motilidad de enjambre, una fuerte capacidad de supervivencia y un conjunto de genes que codifican sustancias bioactivas conocidas por estimular el crecimiento o las defensas de las plantas, influir en la microbiota beneficiosa y contrarrestar la agresividad de los patógenos. Cuando Bs PTA-271 se probó contra Neofusicoccum parvum BT67 en plantas injertadas de invernadero, Bs PTA-271 y Ta SC1 demostraron que el cultivar contribuye a los efectos beneficiosos de Bs PTA-271 y Ta SC1 contra Np-Bt67. La aplicación simultánea de ambos BCAs demostró ser beneficiosa contra este patógeno en vides del cultivar Tempranillo. El análisis transcriptómico de las mismas muestras mostró ampliamente los cambios en la fisiología de la planta inducidos tanto por Bs PTA-271 como por Ta SC1 para proteger la vid ante la infección por Np-Bt67. En Chardonnay, las plantas infectadas con Np-Bt67 presentan genes sobreexpresados que están implicados en las vías de señalización del acido absicico (ABA). En Tempranillo, la infección con Np-Bt67 provoca cambios de expresión en más de 200 genes, relacionados sobre todo con la importación de aminoácidos, procesos relacionados con el cloroplasto y el fotosistema, respuestas de la planta a estímulos bióticos y biosíntesis de metabolitos secundarios. La protección de Ta SC1 en las plantas de Tempranilllo implica un mayor número de cambios, que abarcan tanto el metabolismo primario como el secundario, relacionados con cambios en las señales hormonales, como con el aicdo absicico (ABA). Durante el proceso de producción de la vid en vivero, los resultados demostraron una reducción significativa del porcentaje de plantas infectadas con los patógenos asociados a las enfermedades de decaimiento por Botryosphaeria y Pie negro en el material de vivero tratado con Ta SC1 y Bs PTA-271 respectivamente. Los tratamientos simultáneos con ambos BCAs presentaron una reducción en el porcentaje de plantas infectadas con ambos tipos de patógenos. Al probar el efecto de Bs PTA-271 y Ta SC1 en el microbioma de la rizosfera de la vid de dos suelos diferentes infectados con patógenos del pie negro, los resultados muestran que la inoculación de los BCAs parece mejorar las redes del microbioma de la rizosfera y el estado de saneamiento, sin embargo, el efecto beneficioso de los BCAs puede ser dependiente del suelo. En general, este estudio aportó nuevos conocimientos sobre el uso de uno o más BCAs contra varios patógenos asociados a las GTDs, tanto en el vivero como en vides adultas (viñedo). Además, se destacó el modo de acción de ambos BCAs en la protección de la vid. Por lo tanto, estos hallazgos proporcionan, no sólo una mejor comprensión de las interacciones entre los BCAs, la vid y los patógenos, sino que también son una fuerte contribución a una estrategia de gestión sostenible de las GTDs. / [CA] Les plantes de vinya (Vitis vinifera L.) estan exposades a una gran varietat de patògens. En l'actualitat, les malalties fúngiques de la fusta de la vinya (GTDs) es troben entre els principals factors que limiten la productivitat d'aquest cultiu. Una vegada les vinyes estan infectades, la productivitat de la planta disminueix, provocant una mort lenta o apoplética. La investigació d'agents de control biològic (BCAs) capaços de previndre, o almenys minimitzar, l'impacte de les GTDs, es considera una prioritat d'investigació. En aquesta Tesi Doctoral es va caracteritzar en profunditat un agent de biocontrol potencial i, juntament amb un producte comercial biològic ja registrat, tots dos BCAs van ser provats contra diversos patògens agents causals de GTDs, en hivernacle sota condicions controlades, i també durant el procés de propagació de la vinya en viver. Els resultats de l'anàlisi genòmica completa de Bs PTA-271 mostren un sistema funcional de motilitat d'eixam, una forta capacitat de supervivència i un conjunt de gens que codifiquen substàncies bioactivas conegudes per estimular el creixement o les defenses de les plantes, influir en la microbiota beneficiosa i contrarestar l'agressivitat dels patògens. Quan Bs PTA-271 es va provar contra Np BT67 en plantes empeltades d'hivernacle, Bs PTA-271 i Ta SC1 van demostrar que la cultivar contribueix als efectes beneficiosos de Bs PTA-271 i Ta SC1 contra Np-Bt67. L'aplicació simultània de tots dos BCAs va demostrar ser beneficiosa contra aquest patogen en vinyes del cultivar Ull de llebre. L'anàlisi transcriptómico de les mateixes mostres va mostrar àmpliament els canvis en la fisiologia de la planta induïts tant per Bs PTA-271 com per Ta SC1 per a protegir la vinya davant la infecció per Np-Bt67. En Chardonnay, les plantes infectades amb Np-Bt67 presenten gens sobreexpresados que estan implicats en les vies de senyalització de l'acidifique absicico (ABA). En Ull de llebre, la infecció amb Np-Bt67 provoca canvis d'expressió en més de 200 gens, relacionats sobretot amb la importació d'aminoàcids, processos relacionats amb el cloroplast i el fotosistema, respostes de la planta a estímuls biòtics i biosíntesis de metabòlits secundaris. La protecció de Bs PTA-271 en Chardonnay implica gens relacionats amb la biosíntesi d'ABA, les vies dels fenilpropanoides, els metabòlits secundaris, i l'estructura i organització de la paret cellular. La protecció de Ta SC1 en les plantes de Tempranilllo implica un major nombre de canvis, que abasten tant el metabolisme primari com el secundari, relacionats amb canvis en els senyals hormonals, com amb l'acid abcísic (ABA). Durant el procés de producció de la vinya en viver, els resultats van demostrar una reducció significativa del percentatge de plantes infectades amb els patògens associats a les malalties de decaïment per Botryosphaeria i Peu negre en el material de viver tractat amb Ta SC1 i Bs PTA-271 respectivament. Els tractaments simultanis amb tots dos BCAs van presentar una reducció en el percentatge de plantes infectades amb tots dos tipus de patògens. En provar l'efecte de Bs PTA-271 i Ta SC1 en el microbioma de la rizosfera de la vinya de dos sòls diferents infectats amb patògens del Peu negre, els resultats mostren que la inoculació dels BCAs sembla millorar les xarxes del microbioma de la rizosfera i l'estat de sanejament, no obstant això, l'efecte beneficiós dels BCAs pot ser dependent del sòl. En general, aquest estudi va aportar nous coneixements sobre l'ús d'un o més BCAs contra diversos patògens associats a les GTDs, tant en el viver com en vinyes adultes. A més, es va destacar la manera d'acció de tots dos BCAs en la protecció de la vinya. Per tant, aquestes troballes proporcionen, no sols una millor comprensió de les interaccions entre els BCAs, la vinya i els patògens, sinó que també són una forta contribució a una estratègia de gestió sostenible de les GTDs. / [EN] Grapevine (Vitis vinifera L.) plants are exposed to a wide variety of pathogens. Nowadays, grapevine fungal trunk diseases (GTDs) are amongst the main constraints for the productivity of this crop. Once infected, plant productivity is decreased, leading to a plant slow or apoplectic death. Investigation of biocontrol agents (BCAs) capable to forestall or at least to minimize the impact of GTDs, while being a sustainable treatment, is viewed as a research priority. One potential BCA was deeply characterized, and together with a biological commercial product, both BCAs were tested against several GTD pathogens, in greenhouse under controlled conditions, and during the grapevine propagation process. Results from the full genomic analysis of Bacillus subtilis PTA-271 (as BCA with a potential) show a functional swarming motility system, strong survival capacities and a set of genes encoding for bioactive substances known to stimulate plant growth or defenses, influence beneficial microbiota, and counteract pathogen aggressiveness. When tested against Neofusicoccum parvum Bt67 (thereafter Np-Bt67) in greenhouse cuttings, B. subtilis PTA-271 (Bs PTA-271) and T. atroviride SC1 (Ta SC1) proved that the cultivar contributes to their beneficial effects against Np-Bt67. The simultaneous application of both BCAs was further proved to be even more effective to protect Tempranillo cuttings. Moreover, the transcriptomic analysis from the same samples showed extensively the plant physiology changes induced by the pathogen but also by each BCA, Bs PTA-271 on Chardonnay and Ta SC1 on Tempranillo, to protect grapevine from Np-Bt67 infection. Thus, Chardonnay cuttings infected with Np-Bt67 showed overexpressed genes implicated on abscisic acid (ABA) biosynthesis and signaling pathways. In Tempranillo, the infection with Np-Bt67 leads to more substantial changes in gene expression, related mostly with amino acid import, chloroplast and photosystem related processes, plant responses to biotic stimulus, and biosynthesis of secondary metabolites. Protection induced by Bs PTA-271 in Chardonnay targets genes related to ABA biosynthesis, phenylpropanoid pathways and secondary metabolites, and cell wall structure/organization in relationship with carbohydrate metabolism that requires much more consideration. Protection with Ta SC1 in Tempranilllo requires a larger number of changes related to transporters, cell wall integrity and extension, cell division and pathogen induced cell death, multidirectional active proteins, and microbiome interactions. During the grapevine nursery process, the results demonstrated a significant reduction on the percentage of infected plants with Botryosphaeria dieback and Black-foot pathogens in the material treated with Ta SC1 and Bs PTA-271 respectively. The simultaneous treatments with both BCAs presented a reduction on infected plants with both Botryosphaeria dieback and Black foot pathogens. When testing the effect of Bs PTA- 271 and Ta SC1 in grapevine rhizosphere microbiome of two different soil infected with Black foot pathogens, results show that the inoculation of BCAs seems to improve the rhizosphere microbiome networks and sanitation status, however, the beneficial effect of BCAs can be soil-dependent. Moreover, as observed in the other experiments, the combination of both BCAs improves their beneficial effect in the rhizosphere microbiome. Overall, this study brought new insights on the use of one or more BCAs against several GTD pathogens, from nursery to adult grapevines. Moreover, highlighted both BCAs mode of action in grapevine protection. Thus, these findings provide, not only a better understanding of BCAs, grapevine, and pathogens interactions, but are also a strong contribution for the future development of sustainable GTDs management strategies. / Cunha Maia Leal, CD. (2022). Sustainable Management of Grapevine Trunk Diseases in Vineyard: Deliver Biocontrol Agents and Associated Molecules [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/191261

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