Tesi sul tema "Defense induction"
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1
Rohde, Sven [Verfasser]. "Defense induction in marine macroalgae: Its prevalence, capabilities and limitations / Sven Rohde". Kiel : Universitätsbibliothek Kiel, 2008. http://d-nb.info/1019552956/34.
2
Knebel, Larissa. "RESIN FLOW INDUCTION IN SOUTHERN PINES: IMPLICATIONS FOR DEFENSE AGAINST SOUTHERN PINE BEETLE". NCSU, 2005. http://www.lib.ncsu.edu/theses/available/etd-05162005-201137/.
Abstract (sommario):
The interactions between conifers, bark beetles and their common fungal associates have been widely studied, in part due to the severe economic and natural losses that occur annually. Host resistance, involving constitutive and induced defensive measures, and the factors associated with pest success are now widely understood and some losses can be avoided with proper management. Recent research with Norway spruce (Picea abies) has provided additional insight into the chemical pathways involved in host resistance, and has determined that trees exposed to mechanical wounding or fungal inoculation show acquired resistance to future pathogen attacks. This aspect of defense in loblolly pine (Pinus taeda) has not been adequately investigated. However, our recent studies indicate that fungal inoculation results in elevated resin flow levels that last up to one year after treatment. Further research in southern Appalachian pines showed that elevated resin flow occurs in response to low intensity fire, and that this response is still present at 18 months after burning. These studies indicate that acquired resistance through induced resin flow in southern pines is a possibility. Further research with beetle or fungal challenges could determine new possibilities for management of both natural and planted stands in order to maximize host defenses against southern pine beetle.
3
Das, Shibu. "Analysis of specific transcripts following induction of defense in tea against foliar fungal pathogens". Thesis, University of North Bengal, 2017. http://ir.nbu.ac.in/hdl.handle.net/123456789/2651.
4
Jiang, Mingyi. "Role and mechanism of abscisic acid in the induction of antioxidant defense in maize leaves". HKBU Institutional Repository, 2002. http://repository.hkbu.edu.hk/etd_ra/415.
5
Freitas, ValdinÃia Soares. "Polyamines and ethylene metabolisms and antioxidative defense system induction in two maize genotypes contrasting in salinity tolerance". Universidade Federal do CearÃ, 2015. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=15060.
Abstract (sommario):
CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel SuperiorPolyamines and ethylene have been cited as important regulators of plant growth and development, and may be involved in plant defense against several abiotic stresses, such as salinity. To withstand with salt harmful effects, plants respond through a coordinated set of physiological and molecular responses to improve their performance under salinity. In order to test the hypothesis that salt tolerance degree in maize genotypes is related to changes in polyamine metabolism associated with ethylene production, two experiments were performed. In the first one, BR5033 (salt-tolerant) and BR5011 (salt-sensitive) maize genotypes were subjected to 80 mM NaCl stress to identify the pattern of ethylene production in leaves and roots. Two peaks of ethylene production at 5.5 h (phase I) and 12.5 h (phase II) after onset the salinity treatment were registered in salt-sensitive leaves; whereas only the first peak of ethylene synthesis was detected in salt-tolerant leaves. Surprisingly, the biphasic ethylene production in roots was much less pronounced than in leaves. In the second experiment, we sought to investigate whether the phases I and II of ethylene production alter the polyamine metabolism in the leaves of maize genotypes. In salt-tolerant genotype, the phase I of ethylene synthesis was associated with signaling events, as evidenced by increased H2O2 levels, which were generated by putrescine (Put) catabolism. An early signaling (at 5.5 h) in the salt-tolerant genotype seemed to be effective to suppress the second peak of ethylene production, known as âstress ethyleneâ. Yet, in the salt-sensitive genotype, the decreased H2O2 concentration during the phase I was associated with a marked increase in ethylene production, which was resulted from upregulation of acid 1-aminocyclopropane-1-carboxylic acid oxidase (ACO) activity and ZmACO5 gene expression. At the phase I, the total polyamine content was increased by salinity in the salt-tolerant, whereas it was decreased in the salt-sensitive one. In the salt-tolerant genotype, the increased total polyamine was sustained by high spermine (Spm) and spermidine (Spd) contents, while the decay in the salt-sensitive genotype was due to the reductions of Put and Spd forms. Otherwise, in the phase II, no significant changes in the total polyamines in salt-tolerant genotype (it was likely due to conversion of Put to Spm/Spd), and decreases in salt-sensitive genotype were registered. Under stress conditions, the salinity-induced improvement of Spd and Spm (free and soluble conjugated forms) in salt-tolerant genotype was bigger than in salt-sensitive one, thus suggesting a key role of polyamines in the maize salt stress acclimation processes. Finally, we investigated if the lack of ethylene production during phase II in salt-tolerant genotype was correlated to improved antioxidant capacity. Salt stress dramatically increased the superoxide levels, the electrolyte leakage and lipid peroxidation, it being more pronounced in both leaves and roots of salt-sensitive genotype. On the other hand, under salinity, salt-tolerant genotype displayed a better performance of enzymatic and non-enzymatic antioxidant system, evidenced by a higher ascorbate and glutathione content and upregulation of superoxide dismutase, ascorbate peroxidase and guaiacol peroxidase activity. In conclusion, our results suggest that the ethylene is intimately involved in salt stress acclimation through activation of intricate signaling pathways mediated by H2O2 that is originated from polyamine catabolism. An efficient signal network raises the polyamine content and antioxidant capacity and is responsible, at least in part, for greater tolerance to salinity of BR5033 maize genotype.
Poliaminas e etileno sÃo reguladores do crescimento e desenvolvimento vegetal, que tambÃm estÃo envolvidos nas respostas de defesa das plantas contra estresses abiÃticos, dentre eles a salinidade. Para lidar com o estresse salino, as plantas realizam ajustes fisiolÃgicos, bioquÃmicos e moleculares, que podem resultar em sua aclimataÃÃo diante dessa condiÃÃo adversa, tornando o indivÃduo mais tolerante ao estresse, em comparaÃÃo Ãqueles que nÃo se encontram aclimatados. Essa pesquisa foi desenvolvida para testar à hipÃtese de que o grau de tolerÃncia à salinidade entre genÃtipos de milho envolve alteraÃÃes no metabolismo das poliaminas associadas à produÃÃo de etileno. Para isso, foram realizados dois experimentos. No primeiro, plantas de milho dos genÃtipos BR5011 (sensÃvel) e BR5033 (tolerante) foram submetidas ao estresse salino (NaCl a 80 mM) para identificar o padrÃo de produÃÃo de etileno em folhas e raÃzes. Nas folhas do genÃtipo sensÃvel, a salinidade intensificou a produÃÃo de etileno apÃs 5,5 h (fase I) e 12,5 h (fase II) apÃs o inÃcio do estresse, enquanto no tolerante isso aconteceu somente com 5,5 h. Nas raÃzes, embora tenha sido observada a produÃÃo bifÃsica de etileno no genÃtipo sensÃvel, esse processo foi muito menos intenso que nas folhas. O segundo experimento teve como objetivo principal investigar se a produÃÃo de etileno pela salinidade nas fases I e II resultava em alteraÃÃes no metabolismo das poliaminas nas folhas dos genÃtipos de milho. No genÃtipo tolerante, a fase I de produÃÃo de etileno foi associada à eventos de sinalizaÃÃo, dado o aumento dos teores de H2O2, mediado pelo catabolismo da putrescina (Put). Essa sinalizaÃÃo pareceu ser eficiente para suprimir a produÃÃo do etileno em condiÃÃes de estresse (fase II ou âetileno do estresseâ) nesse genÃtipo. Jà no sensÃvel, a diminuiÃÃo dos teores de H2O2 na fase I foi acompanhada por um aumento acentuado na produÃÃo do etileno, decorrente de acrÃscimos na atividade da enzima oxidase do Ãcido 1-carboxÃlico-1-aminociclopropano (ACO) e na expressÃo de transcritos do gene ZmACO5 (principal membro expresso). Em geral, a salinidade aumentou os teores de poliaminas totais no genÃtipo tolerante, enquanto reduziu no sensÃvel. Na fase I, na condiÃÃo salina quando comparada com o controle, os teores de poliaminas totais foram aumentados no genÃtipo tolerante enquanto no sensÃvel esses teores foram reduzidos. No genÃtipo tolerante, o aumento nos teores de poliaminas totais foi sustentado principalmente pelo aumento nos teores de espermina (Spm) e espermidina (Spd), enquanto a diminuiÃÃo observada no genÃtipo sensÃvel foi devida, sobretudo, Ãs reduÃÃes nas formas de Put e Spd. Jà na fase II, no genÃtipo tolerante nÃo houve alteraÃÃes nos teores totais de poliaminas (provavelmente, devido a utilizaÃÃo de Put para a sÃntese de Spm e Spd), enquanto no sensÃvel esses teores foram reduzidos. Sob condiÃÃes de salinidade, o aumento nas formas livre e conjugada solÃvel de Spm e Spd foi mais pronunciado no genÃtipo tolerante do que no sensÃvel, sugerindo assim importante papel para essas duas poliaminas nos processos de aclimataÃÃo ao estresse salino em plantas de milho. Por fim, foi investigado se a ausÃncia de produÃÃo do etileno na fase II, causado pela salinidade no genÃtipo tolerante, foi relacionada com uma melhor capacidade antioxidante. O estresse salino aumentou drasticamente os teores do radical superÃxido, o vazamento de eletrÃlitos e a peroxidaÃÃo lipÃdica, sendo isso mais pronunciado nas folhas e raÃzes do genÃtipo sensÃvel. De modo geral, o genÃtipo tolerante teve melhor desempenho do sistema antioxidante enzimÃtico e nÃo enzimÃtico, sob condiÃÃes de estresse salino, evidenciado pelos maiores incrementos nos teores de ascorbato e glutationa e na atividade das enzimas dismutase do superÃxido, peroxidase do ascorbato e peroxidase do guaiacol. Em conclusÃo, os resultados aqui apresentados sugerem que o etileno està intimamente envolvido na aclimataÃÃo ao estresse salino, por meio da ativaÃÃo de vias de sinalizaÃÃo mediadas pelo H2O2 produzido a partir do catabolismo de poliaminas. AlÃm disso, sugere-se que essa sinalizaÃÃo induz o aumento nos teores de poliaminas e melhor capacidade antioxidante no genÃtipo BR5033, sendo isto, pelo menos em parte, responsÃvel por sua maior tolerÃncia ao estresse salino, quando comparado ao BR5011.
6
PIERREL, MARIE-AGNES. "Induction du metabolisme aromatique, notamment de la synthese d'acide salicylique lors des reponses de defense du tabac". Université Louis Pasteur (Strasbourg) (1971-2008), 1999. http://www.theses.fr/1999STR13051.
Abstract (sommario):
L'acide salicylique (as), un metabolite phenolique issu de la voie des phenylpropanoides, est l'une des composantes naturelles de la transduction du signal, ou le signal lui-meme, conduisant au phenomene de resistance induite chez les plantes, en reponse a une agression par un agent pathogene. De par le role essentiel joue par cette molecule de signalisation dans le regne vegetal, la modulation de sa teneur endogene offre une perspective interessante d'augmenter la resistance des plantes par genie genetique. Actuellement, aucun gene codant pour une enzyme specifique de sa biosynthese n'a ete clone et tres peu de donnees sont disponibles concernant l'implication d'intermediaires biosynthetiques putatifs dans les etapes cles de regulation. Nos travaux ont montre que l'induction de la synthese de novo de l'as chez le tabac necessite apres infection par le vmt ou induction par un eliciteur fongique, la stimulation de la premiere enzyme de la voie generale des phenylpropanoides : la phenylalanine ammoniac-lyase (pal). L'acide piperonylique (ap), un inhibiteur de la cinnamate 4-hydroxylase (c#4h) i) s'est revele un outil extremement puissant pour devier in vivo le flux de precurseurs dans la partie amont de la voie metabolique conduisant a l'as, ii) nous a permis de preciser le role mineur de l'acide benzoique libre (ab) comme intermediaire dans la synthese d'as. L'apport exogene d'ab a des cultures cellulaires de tabac a mis en evidence l'implication d'une activite benzoate 2-hydroxylase (ba#2h) convertissant l'ab en as par une systeme inductible relie a un processus de detoxication et non correle a l'accumulation d'as in vivo. L'ensemble de ces resultats permet donc de proposer l'existence d'une voie metabolique conduisant a la synthese d'as chez le tabac, independante de celle de l'ab et faisant intervenir un mecanisme de -oxydation, conduisant au benzoyl-coa, a partir de l'acide cinnamique.
7
Gully, Kay. "The plant immune system : induction, memory and de-priming of defense responses by endogenous, exogenous and synthetic elicitors". Thesis, Angers, 2019. http://www.theses.fr/2019ANGE0001/document.
Abstract (sommario):
En tant qu’organismes sessiles, les plantes doivent réagir rapidement et intensément, via des réponses défensives, pour repousser les pathogènes invasifs. Le système immunitaire des plantes peut être déclenché par des molécules élicitrices exogènes ou endogènes. Une autre classe d’éliciteurs, les éliciteurs synthétiques, contient également des composés promouvant une réponse défensive.Dans ce manuscrit, je décris la découverte et caractérisation d’une nouvelle famille de petits peptides endogènes potentiellement sécrétés(PROSCOOP), dont les membres incluent de petits peptides (SCOOP). Je démontre que les SCOOP sont impliqués dans les mécanismes de défense de la plante et le développement racinaire. Une variété de peptides SCOOP induit des réponses défensives de courtes et longues durées.De plus, des traitements avec le peptideSCOOP12 induisent une résistance à Pseudomonas syringae chez Arabidopsis.Dans la seconde partie de cette thèse, je démontre que le traitement des plantes avec un éliciteur synthétique peut mener à une mémoire transcriptionnelle à long terme, et que le challenge subséquent des plantes traitées par application d’un éliciteur exogène désactive cette mémoire transcriptionnelle. En conclusion, ma thèse présente (1) la diversité des fonctions que peuvent avoir ces éliciteurs et (2) l’impact sur les systèmes de défense de la plante et ses conséquences sur la mémoire et le développement de la planteAs sessile organism, plants have to react quickly and strongly with defense responses to repel any invading pathogen. The plant immune system can be triggered by exogenous or endogenous elicitor molecules. Another class of elicitors are defense promoting compounds which are also known as synthetic elicitors. Here I describe the discovery and characterization of a novel family of potentially secreted small endogenous peptides (PROSCOOP) which members harbor small peptides (SCOOPs). I show that the SCOOP family is involved in plant defense and root development. Various SCOOP peptides induce short- and long-term defense responses. Moreover, treatments with the SCOOP12 peptide induce the resistance against Pseudomonas syringae in Arabidopsis. In the second part of this thesis, I show that treatments with a synthetic elicitor can lead to long-term transcriptional memory and that subsequent challenging of such plants with an exogenous elicitor reverted this transcriptional memory. In conclusion, my thesis shows (1) how diverse the function of these elicitors can be and (2) the impact the plant defense system and its triggers have on plant development and memory
8
Subedi, Nagendra. "Use of Biorational Products for the Control of Diseases in HighTunnel Tomatoes and Induction of Certain Defense Genes in tomato by Trichoderma hamatum 382". The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1250602215.
9
Sneed, Jennifer M. "The Effects of Labyrinthula sp. Infection, Salinity, and Light on the Production of Phenolic Compounds in Thalassia testudinum". [Tampa, Fla.] : University of South Florida, 2005. http://purl.fcla.edu/fcla/etd/SFE0001230.
10
Morais, Vanessa Duarte de. "AvaliaÃÃo da expressÃo gÃnica da toxina da soja (SBTX) por indutores da defesa de plantas". Universidade Federal do CearÃ, 2012. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=10580.
Abstract (sommario):
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel SuperiorA soja à uma das leguminosas mais utilizadas no mundo, sendo o uso justificado pelo elevado teor nutricional de seus grÃos, constituÃdos, principalmente, por proteÃnas e lipÃdios. A estimativa atual da produÃÃo mundial de soja à de 250.000 toneladas/ano, porÃm hà fatores limitantes dessa produÃÃo, como o ataque de pragas. As doenÃas causadas por fungos, por exemplo, causam na soja perdas em torno de 4%, sendo 20% destas causadas por Septoria glycines e Cercospora kikuchii. Assim, a busca por medidas alternativas de controle à crescente, particularmente em diminuiÃÃo ao uso de agrotÃxicos, mas, para isso, à importante o entendimento dos mecanismos de defesa vegetal. Das sementes de soja foi purificada uma proteÃna, denominada toxina da soja (SBTX), que à ativa contra diversos fungos de plantas e do homem e, tambÃm, à neurotÃxica para ratos e camundongos, razÃo pela qual recebeu o nome de toxina. A SBTX apresenta massa molecular de 44 kDa, constituÃda por duas subunidades (17 e 27 kDa) codificadas por genes distintos e jà foi identificada nas sementes, raÃzes, caules e folhas. O presente trabalho teve como objetivo avaliar o perfil de expressÃo gÃnica da SBTX em plantas cujas folhas primÃrias foram tratadas com elicitores (biÃtico e abiÃtico), usando a tÃcnica de PCR em tempo real, na tentativa de reforÃar o papel fisiolÃgico de defesa proposto para proteÃna. Assim sendo, Ãcido salicÃlico, injÃria mecÃnica e esporos do fungo Cercospora kikuchii foram utilizados como elicitores e os nÃveis de transcritos para as duas subunidades proteicas de SBTX avaliados. Respostas de induÃÃo foram verificadas para ambas as subunidades da SBTX, porÃm os perfis de expressÃo gÃnica foram diferenciados. Para o gene SBTX 27 kDa, o maior nÃvel de transcritos foi detectado quando o tratamento envolveu injÃria mecÃnica associada ao Ãcido salicÃlico, correspondendo a um aumento de cerca de 100 vezes apÃs 12 horas de aplicaÃÃo do tratamento. Jà para o gene SBTX 17 kDa este aumento nÃo foi verificado na mesma intensidade, tendo sido apenas em torno de 10 vezes. Os dados em conjunto mostram que SBTX à uma proteÃna passÃvel de induÃÃo por elicitores biÃticos e abiÃticos, reforÃando o seu papel fisiolÃgico de defesa, podendo vir a ser utilizada como ferramenta biotecnolÃgica no sentido de amenizar as perdas causadas por fungos.
Soybean is a legume most commonly utilized in the world, whose use is justified by the high nutritional content of its grain, consisting mainly of proteins and lipids. The current estimate of global soybean production is 250,000 tons/year, but there are limiting factors of this production, such as the pest attack. The fungal diseases, for example, cause losses in soybeans around 4%, where 20% of these are derived from infection by Septoria glycines and Cercospora kikuchii. Thus, the search for alternative measures is increasing, particularly in reducing the use of pesticides, but for this it is important to understand the plant defense mechanisms. Soybean toxin (SBTX) is a protein purified from soybean seeds with activity against plant and human pathogenic fungi and neurotoxic action to rats and mice, hence the reason it received the name of toxin. SBTX shows a molecular mass of 44 kDa, composed of two subunits (17 and 27 kDa) encoded by distinct genes and it has been detected seeds, roots, stems and leaves. This study aimed to evaluate the gene expression profile of SBTX in soybean plants whose primary leaves were treated with elicitors (biotic and abiotic), using the real-time PCR technique, in an attempt to strength the physiological role of defense proposed for this protein. Therefore, salicylic acid, mechanic injury and Cercospora kikuchii spores were used as elicitors and it was measured the transcript levels of SBTX subunits. Induction responses were observed for both subunits of SBTX, but the gene expression profiles were different. For SBTX 27 kDa gene, the highest transcript level was detected when the treatment involved mechanic injury associated to salicylic acid, an increase of about 100 fold after 12 hours of treatment application. Nevertheless, for SBTX 17 kDa gene the induction response was much smaller, it was only around 10 times. The data together show that SBTX is an inducible protein by biotic and abiotic elicitors, reinforcing its physiological role of defense, which could eventually be used as biotechnological tool in order to mitigate losses caused by fungi.
11
Ganeson, Menaka. "The effect of chitosan on growth and enzyme production in Ganoderma sp. in vitro and in vivo induction of plant defense response in oil palm". Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/30573/.
Abstract (sommario):
The aim of this study was to evaluate the role of chitosan against Ganoderma pathogen of basal stem rot (BSR) disease under in vitro and in vivo conditions. Therefore, this study was conducted to investigate the effect of chitosan on (1) in vitro growth of Ganoderma sp. (2) production of lignin degrading enzymes (LDE) by Ganoderma sp. under in vitro cultivation system (3) disease severity and vegetative growth parameters on oil palm seedlings and (4) elicitation of plant defense response during the interaction between host-pathogen (oil palm-Ganoderma).
12
Arantes, Mariana Reis. "ExpressÃo gÃnica da toxina da soja (SBTX) durante o desenvolvimento da soja [Glycine max (L.) Merril] e seu envolvimento na defesa vegetal". Universidade Federal do CearÃ, 2015. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=14688.
Abstract (sommario):
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgicoO Brasil à o segundo maior produtor mundial de soja, destacando-se por sua multiplicidade de uso. Entretanto, perdas na produtividade de seus grÃos em campo sÃo ainda considerÃveis, particularmente oriundas das doenÃas causadas por fungos. Diante desse obstÃculo, emerge a necessidade de busca de molÃculas naturais capazes de inibir o progresso dessas doenÃas, sem causar impactos ambientais. Dentre as molÃculas presentes na soja, com potencial de uso para essa finalidade, destaca-se a toxina da soja (SBTX), uma proteÃna isolada de sementes, composta por duas subunidades (17 e 27 kDa) e ativa contra fungos fitopatogÃnicos. Esse trabalho teve como objetivos verificar a localizaÃÃo tecidual da SBTX em cotilÃdones de sementes maduras, bem como avaliar seu perfil de expressÃo gÃnica ao longo do desenvolvimento da soja e, tambÃm, em resposta ao tratamento com elicitores de defesa vegetal. Sementes de soja foram cultivadas em casa de vegetaÃÃo e, ao longo do desenvolvimento da planta, diferentes tecidos vegetais coletados. Em adiÃÃo, folhas primÃrias da soja foram tratadas com Ãcido salicÃlico (AS) ou inoculadas com esporos do fungo Cercospora kikuchii (CK) e coletadas em diferentes tempos apÃs os tratamentos. Iniciadores foram desenhados com base nas sequÃncias NH2-terminal das subunidades de SBTX e a expressÃo gÃnica foi avaliada pela tÃcnica de RT-PCR quantitativa. A localizaÃÃo de SBTX em sementes foi avaliada por imunohistoquÃmica, usando anti-SBTX. Transcritos dos genes SBTX17 e SBTX27 foram detectados em todos os tecidos vegetais coletados, porÃm seus nÃveis de expressÃo foram diferenciados. NÃveis mais elevados de transcritos para ambas as subunidades da SBTX foram detectados em sementes maduras, cotilÃdones e folhas unifoliadas. Nos cotilÃdones, SBTX foi encontrada na epiderme. InduÃÃo da expressÃo de transcritos da SBTX ocorreu em ambos os tratamentos, porÃm essa resposta se manifestou mais rÃpida (a partir de 6 h) com CK ao invÃs de AS (a partir de 12 h). Praticamente, em todas as anÃlises, transcritos do gene SBTX27 prevaleceram em relaÃÃo Ãqueles do SBTX17. A presenÃa constitutiva e ubÃqua de transcritos dos genes da SBTX ao longo do desenvolvimento da planta, a induÃÃo da expressÃo desses genes por elicitores de resposta de defesa e a localizaÃÃo da toxina na superfÃcie dos cotilÃdones validam o papel de defesa atribuÃdo a SBTX, suscitando a possibilidade de uso dessa proteÃna na produÃÃo de soja resistente ao ataque de fungos de relevÃncia agronÃmica.
Brazil is the second major global soybean producer, whose magnitude is due to its use multiples. However, losses in productivity of soybean grains in the field are still significant, especially those caused by pathogenic fungi. In view of this obstacle, it is important to search natural molecules able to inhibiting the progress of fungal diseases in an environmental friendly practice. Among the soybean molecules which could be used for this purpose, the soybean toxin (SBTX) stands out. SBTX is a protein composed of two subunits (17 and 27 kDa) isolated from seeds with in vitro activity against phytopathogenic fungi. The present study aimed to verify the SBTX tissue localization in soybean seed cotyledons, as well as to evaluate the gene expression profile of two SBTX subunits, both in different stages of plant development and in response to treatment with plant defense elicitors. Soybean seeds were grown in a greenhouse and plant tissues harvested at different days. In addition, soybean primary leaves were treated with salicylic acid (SA) or inoculated with the Cercospora kikuchiii (CK) spores and harvested at different times after the treatments. Based on the N-terminal sequences of the SBTX subunits, primers were designed and their gene expression evaluated by quantitative real-time PCR technique. SBTX tissue localization was performed by immunohistochemistry using anti-SBTX. Transcripts for both SBTX subunits were detected in all plant tissues, predominantly in cotyledons and unifoliate leaves in the early stages of their development, as well as in mature seeds. SBTX was found in the epidermis of the cotyledons. Transcripts were detected for both genes SBTX17 e SBTX27 in all tissues collected, but their expression levels were different. The highest transcript levels for both SBTX subunits were found in mature seeds, cotyledons and unifoliate leaves. In cotyledons, SBTX was found in the epidermis. Leaves treated with elicitors showed induction of the corresponding 17 and 27 kDa subunit transcripts, however this response was earlier in the CK treatment (from 6 h) compared to AS treatment (from 12 h). In almost all analyses, the highest transcript levels were found for the 27 kDa subunit. The ubiquitous and constitutive gene expression during plant development, the induction of gene expression by defense response elicitors and the localization on the surface of cotyledons support the role of SBTX in plant defense and its use to produce fungal-resistant transgenic soybean plants.
13
RENAULT, ANNE-SOPHIE. "Induction de proteines de defense dans les feuilles de vigne infectees par botrytis cinerea : identification d'une beta-1, 3-glucanase (pr2) et etude de son expression spatio-temporelle". Reims, 1998. http://www.theses.fr/1998REIMS034.
Abstract (sommario):
La vigne est regulierement agressee par de nombreux pathogenes, notamment par botrytis cinerea, l'agent responsable de la pourriture grise. La mise au point d'une methode biologique de lutte contre ce champignon passe par la caracterisation des mecanismes de defense naturels de la vigne. C'est dans le cadre de cette etude que nous nous sommes interesses aux proteines produites en reponse a l'infection par b. Cinerea : les pathogenesis-related proteins (prs) ou proteines de defense. Les prs ont ete identifiees par des electrophoreses en simple et double dimension puis caracterisees. En utilisant des anticorps heterologues, nous avons montre que certaines de ces prs appartiennent aux familles des pr2 (-1,3-glucanases), des pr3 (chitinases) et des pr10 (ribonuclease-like). Le microsequencage partiel de l'une des isoformes de pr2 a conduit a la caracterisation d'une proteine de 34 kda, de point isoelectrique 5. 7, qui est la premiere -1,3-glucanase acide mise en evidence chez la vigne, en reponse a une agression. La cinetique de synthese des -1,3-glucanases a ete suivie aux niveaux de la transcription et de la traduction. L'utilisation d'une sonde homologue a montre que les arnm s'accumulent de 3 a 7 jours apres l'infection avec un maximum a 5 jours. Les proteines sont synthetisees de facon croissante du 3#e#m#e au 7#e#m#e jour suggerant que la synthese des -1,3-glucanases est controlee principalement au niveau transcriptionnel. L'etude spatiale de la production de ces enzymes montre qu'elles sont aussi induites a distance du site d'infection, c'est-a-dire que la reponse de la vigne au pathogene est, du moins dans la feuille, systemique. Nous avons evalue le role que pourraient jouer les prs dans la lutte contre b. Cinerea. L'analyse des prs induites par 4 souches de b. Cinerea presentant des vitesses de croissance differentes n'a pas revele de differences significatives. Toutefois des tests in vivo ont montre un ralentissement significatif de la vitesse de croissance du champignon lorsque les prs etaient prealablement produites. Ces resultats indiquent que l'induction controlee des prs pourrait contribuer a elaborer, pour la vigne, de nouvelles methodes de lutte contre b. Cinerea et les autres pathogenes fongiques.
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Roby, Dominique. "Reactions de defense et expression genique de plantes de melon en reponse a une infection fongique". Toulouse 3, 1987. http://www.theses.fr/1987TOU30079.
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Morais, Vanessa Duarte de. "Avaliação da expressão gênica da toxina da soja (SBTX) por indutores da defesa de plantas". reponame:Repositório Institucional da UFC, 2012. http://www.repositorio.ufc.br/handle/riufc/18864.
Abstract (sommario):
MORAIS, Vanessa Duarte de. Avaliação da expressão gênica da toxina da soja (SBTX) por indutores da defesa de plantas. 2012. 92 f. Dissertação (Mestrado em Bioquímica)-Universidade Federal do Ceará, Fortaleza-CE, 2012.Submitted by Eric Santiago (erichhcl@gmail.com) on 2016-07-15T13:11:16Z No. of bitstreams: 1 2012_dis_vdmorais.pdf: 9943329 bytes, checksum: 9b36af801a5a86f10c3a4153e39f1e80 (MD5)
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Soybean is a legume most commonly utilized in the world, whose use is justified by the high nutritional content of its grain, consisting mainly of proteins and lipids. The current estimate of global soybean production is 250,000 tons/year, but there are limiting factors of this production, such as the pest attack. The fungal diseases, for example, cause losses in soybeans around 4%, where 20% of these are derived from infection by Septoria glycines and Cercospora kikuchii. Thus, the search for alternative measures is increasing, particularly in reducing the use of pesticides, but for this it is important to understand the plant defense mechanisms. Soybean toxin (SBTX) is a protein purified from soybean seeds with activity against plant and human pathogenic fungi and neurotoxic action to rats and mice, hence the reason it received the name of toxin. SBTX shows a molecular mass of 44 kDa, composed of two subunits (17 and 27 kDa) encoded by distinct genes and it has been detected seeds, roots, stems and leaves. This study aimed to evaluate the gene expression profile of SBTX in soybean plants whose primary leaves were treated with elicitors (biotic and abiotic), using the real-time PCR technique, in an attempt to strength the physiological role of defense proposed for this protein. Therefore, salicylic acid, mechanic injury and Cercospora kikuchii spores were used as elicitors and it was measured the transcript levels of SBTX subunits. Induction responses were observed for both subunits of SBTX, but the gene expression profiles were different. For SBTX 27 kDa gene, the highest transcript level was detected when the treatment involved mechanic injury associated to salicylic acid, an increase of about 100 fold after 12 hours of treatment application. Nevertheless, for SBTX 17 kDa gene the induction response was much smaller, it was only around 10 times. The data together show that SBTX is an inducible protein by biotic and abiotic elicitors, reinforcing its physiological role of defense, which could eventually be used as biotechnological tool in order to mitigate losses caused by fungi.
A soja é uma das leguminosas mais utilizadas no mundo, sendo o uso justificado pelo elevado teor nutricional de seus grãos, constituídos, principalmente, por proteínas e lipídios. A estimativa atual da produção mundial de soja é de 250.000 toneladas/ano, porém há fatores limitantes dessa produção, como o ataque de pragas. As doenças causadas por fungos, por exemplo, causam na soja perdas em torno de 4%, sendo 20% destas causadas por Septoria glycines e Cercospora kikuchii. Assim, a busca por medidas alternativas de controle é crescente, particularmente em diminuição ao uso de agrotóxicos, mas, para isso, é importante o entendimento dos mecanismos de defesa vegetal. Das sementes de soja foi purificada uma proteína, denominada toxina da soja (SBTX), que é ativa contra diversos fungos de plantas e do homem e, também, é neurotóxica para ratos e camundongos, razão pela qual recebeu o nome de toxina. A SBTX apresenta massa molecular de 44 kDa, constituída por duas subunidades (17 e 27 kDa) codificadas por genes distintos e já foi identificada nas sementes, raízes, caules e folhas. O presente trabalho teve como objetivo avaliar o perfil de expressão gênica da SBTX em plantas cujas folhas primárias foram tratadas com elicitores (biótico e abiótico), usando a técnica de PCR em tempo real, na tentativa de reforçar o papel fisiológico de defesa proposto para proteína. Assim sendo, ácido salicílico, injúria mecânica e esporos do fungo Cercospora kikuchii foram utilizados como elicitores e os níveis de transcritos para as duas subunidades proteicas de SBTX avaliados. Respostas de indução foram verificadas para ambas as subunidades da SBTX, porém os perfis de expressão gênica foram diferenciados. Para o gene SBTX 27 kDa, o maior nível de transcritos foi detectado quando o tratamento envolveu injúria mecânica associada ao ácido salicílico, correspondendo a um aumento de cerca de 100 vezes após 12 horas de aplicação do tratamento. Já para o gene SBTX 17 kDa este aumento não foi verificado na mesma intensidade, tendo sido apenas em torno de 10 vezes. Os dados em conjunto mostram que SBTX é uma proteína passível de indução por elicitores bióticos e abióticos, reforçando o seu papel fisiológico de defesa, podendo vir a ser utilizada como ferramenta biotecnológica no sentido de amenizar as perdas causadas por fungos.
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Platel, Rémi. "Criblage, efficacité et modes d’action de composés de biocontrôle microbiens sur le pathosystème blé-Zymoseptoria tritici". Electronic Thesis or Diss., Université de Lille (2018-2021), 2021. https://pepite-depot.univ-lille.fr/ToutIDP/EDSMRE/2021/2021LILUR025.pdf.
Abstract (sommario):
La septoriose, causée par le champignon hémibiotrophe Zymoseptoria tritici, est l’une des maladies les plus préjudiciables sur les cultures de blé, responsable de pertes de rendement pouvant atteindre 50%. La lutte contre cette maladie repose essentiellement sur l’utilisation des fongicides conventionnels et, dans une moindre mesure, sur le recours aux ressources variétales. Toutefois, en raison des résistances développées par l’agent pathogène vis-à-vis de ces leviers et d’une demande sociale croissante pour limiter l’utilisation des intrants chimiques en agriculture, des alternatives agroécologiques, comme le biocontrôle, doivent être développées. L’objectif de ce présent projet de thèse se situe dans ce contexte et vise à identifier des composés de biocontrôle efficaces sur le pathosystème blé-Z.tritici et de caractériser leurs modes d’action. Tout d’abord, un criblage in vitro d’un panel de 181 composés microbiens (extraits fongiques ou bactériens, rhamnolipides, lipopeptides, etc.) a été réalisé pour évaluer leur activité antifongique directe vis-à-vis de l’agent pathogène. Les composés les plus actifs ont ensuite été sélectionnés pour vérifier leur efficacité de protection in planta. Une étude de relation structure-activité a été menée avec 19 rhamnolipides (RL) et a révélé que ceux présentant des liaisons ethers ou esters, avec une chaine carbonée hydrophobe de 12 carbones, sont les plus efficaces pour toutes les activités biologiques testées (activité biocide, élicitation des défenses du blé et efficacité de protection). Parmi eux, le Rh-Est-C12 s’est montré le plus prometteur, avec une efficacité de protection de 78,9%. Le potentiel de ce RL, ainsi que de la mycosubtiline, un lipopeptide efficace pour protéger le blé contre Z. tritici, pour stimuler les défenses du blé, a été étudié à l’aide d’une approche combinée de transcriptomique et de métabolomique. Le RL n’a pas déclenché de modifications majeures de la physiologie foliaire de blé ; celui-ci protégerait donc l’hôte principalement via son activité directe vis-à-vis du champignon, alors que la mycosubtiline semble présenter un mode d’action double, basé sur l’activité antifongique directe et la potentialisation des défenses du blé. Cette induction des défenses pourrait résulter de l’interaction de la mycosubtiline avec les membranes cytoplasmiques du blé, conduisant à une accumulation de flavonoïdes dans les feuilles, mais aussi à d’autres réponses dépendantes de la voie de l’acide abscissique. Ces travaux ont par ailleurs permis de mettre en évidence de nouveaux mécanismes dans les réactions de défense du blé vis-à-vis de Z. tritici. Enfin, deux nouvelles souches isolées de Bacillus velezensis ont présenté une activité antifongique prometteuse contre l’agent pathogène, résultant probablement de la production de lipopeptides, comme la baccilomycine D, dont l’activité sur Z. tritici mériterait d’être exploréeSeptoria Tritici Blotch, caused by the hemibiotrophic fungus Zymoseptoria tritici, is one of the most severe diseases on wheat, responsible for yield losses up to 50%. Currently, strategies used to control this disease rely mainly on the use of chemical fungicides, and to a lower extent, on the use of partially resistant cultivars. Nevertheless, because of the pathogen resistances and an increasing social demand to reduce conventional pesticides in agriculture, new agroecological alternative crop protection methods, like biocontrol, must be developed. The main purpose of this thesis project was, therefore, to identify new effective biocontrol compounds on the wheat-Z. tritici pathosystem and to decipher their modes of action. An in vitro screening of a panel of 181 microbial compounds (fungal and bacterial extracts, rhamnolipids, lipopeptides…) was performed to assess their antifungal activity towards the pathogenic agent. The most active compounds were selected for further experiments, such as verifying their protection activity in planta. The ability of 19 rhamnolipids (RLs) to control the pathogen was explored and a structure-activity relationship study revealed that bioinspired RLs with ether or ester links and a 12 carbon hydrophobic fatty acid tail were the most effective for all tested biological activities (biocide activity, wheat defense elicitation and protection efficacy). Among them, Rh-Est-C12 was the most promising compound, with a protection efficacy of 78.9%. The potential of Rh-Est-C12 as well as mycosubtilin, a lipopeptide also effective to protect wheat against Z. tritici, to induce host defenses was investigated using a combined transcriptomic and metabolomic approach. The RL did not trigger any major disorganization of the wheat leaf physiology, hence it would protect the host mainly through its direct activity towards Z. tritici while mycosubtilin would display a dual mode of action, antifungal effect and wheat priming. Mycosubtilin could prime wheat by interacting with its plasma membranes leading to flavonoids accumulation and other abscisic acid dependent responses. New insights in wheat defense mechanisms towards Z. tritici were reported. Finally, two Bacillus velezensis strains, isolated from wheat phyllosphere, displayed promising antifungal effect towards the pathogenic agent. Characterization of their metabolites was performed and the putative role of bacillomycin D molecule family as a potent Z. tritici antifungal lipopeptide was highlighted
17
Lee, Min-Hi. "Induction and regulation of antiviral defence mechanisms through intracytoplasmic sensors". Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2009. http://dx.doi.org/10.18452/15950.
Abstract (sommario):
Das Wechselspiel zwischen Viren und ihren Wirtszellen beginnt meist an pattern recognition-Rezeptoren (PRRs), die für die Erkennung unterschiedlichster Pathogene anhand bestimmter Strukturen, sogenannten pathogen-associated molecular patterns (PAMPs), zuständig sind. Nach Detektion lösen die PRRs über verschiedene Signalkaskaden eine antivirale Antwort aus, die zur Expression antiviraler Gene führt. RIG-I und MDA5 sind zytoplasmatisch lokalisierte PRRs und erkennen RNA-Strukturen, die insbesondere während der viralen Replikation und Transkription verfügbar sind. Hantaviren sind humanpathogene RNA-Viren mit einem einzelsträngigen, segmentierten Genom. Die Konsequenzen hantaviraler Infektionen auf molekularer Ebene wurden bereits detailliert untersucht, aber die Mechanismen, die zur Induktion der Immunantwort führen, wie auch mögliche Immunevasionsstrategien, die wahrscheinlich in Zusammenhang mit der Pathogenität des jeweiligen Hantavirusstamms variieren, konnten bisher nicht identifiziert werden. Da Hantaviren im Cytoplasma ihrer Wirtszellen replizieren, stellen RIG-I und MDA5 potentielle Detektoren dar. In dieser Doktorarbeit wird die Bedeutung von RIG-I und MDA5 für die Erkennung von Hantavirus-Infektionen untersucht. Wachstumskinetiken zeigten, daß RIG-I die Replikation von pathogenen wie auch apathogenen Hantaviren beeinträchtigt. Außerdem konnte die RNA hantaviraler Nukleocapsid- (N-) ORFs als eine virale Komponente identifiziert werden, die Typ I Interferon über RIG-I induziert. Das Ausmaß der Interferon-Aktivierung korrelierte hierbei tendenziell mit dem Virulenzgrad der Virusstämme und war für die nicht-pathogenen Hantaviren nicht nachweisbar. Unterschiede in der Aktivierungsstärke können anhand vorläufiger Daten wahrscheinlich auf noch nicht identifizierte Motive zurückgeführt werden, die am 3’-Ende der N ORFs liegen. Im Gegensatz dazu wurde keine Interferon-Aktivierung durch hantavirale Komponenten über MDA5 festgestellt.Host-virus interaction is usually initated by pattern recognition receptors (PRRs) which are responsible for the recognition of various pathogens based on so-called pathogen-associated molecular patterns (PAMPs). Upon detection, PRRs trigger an antiviral immune response through different signalling cascades that lead to the expression of antiviral genes including interferon genes. RIG-I and MDA5 are cytoplasmically localised PRRs and recognise RNA patterns that are particularly available during viral replication and transcription. Hantaviruses are RNA viruses with single-stranded segmented genomes. The consequences of hantaviral infections have been analysed in detail, but the mechanisms that lead to the induction of the innate immune response as well as immune evasion strategies depending on the pathogenicity of the respective hantavirus strains have not been identified yet. Since hantaviruses replicate in the cytoplasm of their host cells, RIG-I and MDA5 represent potential PRRs for hantaviral detection. This thesis investigates the impact of RIG-I and MDA5 on recognition of hantaviral infections. Growth kinetics show that RIG-I impairs the replication of pathogenic as well as non-pathogenic hantaviruses. Furthermore, the RNA of hantaviral nucleocapsid protein (N) ORF could be identified as a viral component responsible for the induction of RIG-I signalling. It is shown that the degree of interferon promotor activation correlates with the virulence of the hantavirus strain from which the N ORF was derived. Based on preliminary data, differences in activation strength may be attributed to not yet identified motifs at the 3’ end of the ORF. In contrast, no interferon activation through MDA5 could be observed.
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Sá, Mário Moniz de. "Induction of phenylpropanoid metabolism in elicitor-treated hybrid poplar suspension-cultured cells". Thesis, University of British Columbia, 1991. http://hdl.handle.net/2429/30296.
Abstract (sommario):
Induction of phenylpropanoid metabolism in many plants is associated with the induction of plant defence responses. Among these are the accumulation of phenylpropanoid-derived phytoalexins, increase in lignification around infected sites, and the accumulation of wall-bound phenolic compounds. I show in this work, that H11 hybrid cell suspension cultures when treated with either of three elicitors respond with an increase in phenylpropanoid metabolism. Activation proceeds rapidly from PAL and 4CL mRNA accumulation, to a massive increase in extractable PAL enzyme activity and finally there is accumulation of specific phenolic compounds in the cell extracts, culture filtrates, and cell walls. In addition, elicitor treatment causes cells to turn brown, indicative of phenolic compound accumulation. As in other plants, induction is dependent on culture age, is dose dependent, and the kinetics of induction is the same with all three elicitors. Based on the previously established mode of action of PGA lyase as an elicitor, it is concluded that in poplar, as in other plants, defence responses can be induced by elicitors from both fungal and plant cell wall origin. These results illustrate the successful use of plant suspension cultures as a simplified system to study inducible defence responses. In addition, and consistent with the ubiquitous nature of phenolics in poplar, phenylpropanoid metabolism may play an important role in plant defence responses in this species.Science, Faculty of
Botany, Department of
Graduate
19
Lo, Chang-yun. "Optimizing ship air-defense evaluation model using simulation and inductive learning". Thesis, Monterey, California. Naval Postgraduate School, 1991. http://hdl.handle.net/10945/26678.
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Ashfield, Thomas. "Induction of defence-related gene promoters during interactions between tomato and Cladosporium fulvum". Thesis, University of East Anglia, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359321.
21
Hoyos, Rendón Mary Elizabeth. "From signal to gene induction : molecular aspects of bacterial HR /". free to MU campus, to others for purchase, 1998. http://wwwlib.umi.com/cr/mo/fullcit?p9924888.
22
Goh, Kar Mun. "Induction of defence response in lignin biosynthesis of Elaeis guineensis during an interaction with Ganoderma boninense". Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/33466/.
Abstract (sommario):
Oil palm is a dynamic economic crop that provides good income and is a source of dietary energy for the global population by palm oil. However, oil palm has low resistance to basal stem rot (BSR) disease caused by Ganoderma boninense. It is hypothesised that the process of cell wall lignification could serve as the first line of defence in oil palm. Lignification delays the infection progress of G. boninense. This present study evaluated the underlying molecular and biochemical lignin biosynthesis events and the quantification and deposition patterns of lignin in oil palm upon G. boninense infection. In this study, an artificial in planta infection system was used to inoculate one month-old oil palm plantlets with G. boninense (GBLS strain) at three levels of treatments (control, T1; wounded, T2 and infected, T3). Post-infection analyses were conducted at 2 day intervals for a period of 8 days. The analyses included the disease severity index (DSI) and physical properties of the plantlets (height, weight, stem diameter, root length and leaf chlorophyll content), the degree of G. boninense colonisation on plantlets stem tissues, total phenolic content and total amount of G. boninense DNA in planta. The results showed a significant (P < 0.001) reduction in the leaf chlorophyll content (from 32.59 to 12.61 SPAD) and severe deterioration of the internal stem tissues. Escalation of DSI values (from 5.56 to 70.37%), total phenolic contents (from 1.78 to 3.07 mg g-1) and the quantity of G. boninense DNA (from 4.04 to 757.15 mg g-1) in the infected (T3) plantlets on 8 day post-inoculation (DPI) were observed. These differences (P > 0.05) were absent in control (T1) and wounded (T2) plantlets. Colorimetric enzyme assays and quantitative PCR amplifications (qPCR) were carried out to assess the enzyme activities and relative gene expressions of intermediate enzymes (phenylalanine ammonia lyase, PAL; cinnamate 4-hydroxylase, C4H; caffeic acid O-methyltransferase, COMT; cinnamyl alcohol dehydrogenase, CAD) for lignin biosynthesis in oil palm plantlets. Enzyme activities of PAL, C4H and COMT were generally induced in infected plantlets, except for CAD which was reduced in all plantlets throughout the experiment. Meanwhile, relative expression of EgPAL, EgCOMT and EgCAD were up-regulated in infected plantlets by 3 to 6 fold at 2 to 4 DPI as compared to the control plantlets, except for EgC4H which was initially down-regulated, but was induced later at 8 DPI with the highest change recorded of 13.22. A biphasic transient induction pattern of lignin biosynthesis genes was observed in oil palm plantlets upon infection by G. boninense. The lignothioglycolic acid (LTGA) assay, histochemical staining with toluidine blue-O (TBO), Maúle reagent and phloroglucinol-HCl and gas chromatography (GC) equipped with a flame ionisation detector (FID) were used to estimate and detect the total lignin content, lignin deposition patterns and the composition of lignin derivatives such as syringaldehyde and vanillin, respectively. Results showed the infected plantlets scored the highest level of total lignin content at 93.63 TGA g-1 derivatives at 8 DPI. Lignin was mainly deposited on the collenchyma and cuticle layers, as observed via staining with TBO and Maúle reagents, but red colouration from phloroglucinol-HCl, which stained for guaiacyl-lignin was absent in all specimens. Total amounts of syringaldehyde and vanillin increased in infected plantlets at 6 DPI, with higher increment of vanillin (353%) than syringaldehyde (59%) content. From this study, an early induction of lignification in oil palm was confirmed in response to the infection of G. boninense. This resulted in the accumulation and deposition of lignin compounds in the cell walls of oil palm. An increase in lignin content of oil palm was believed to have enhanced its tolerance towards G. boninense infection and delayed the progression of BSR disease, which could be a temporary solution to the BSR problem in oil palm. Further research for an effective cure or prevention is required.
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Pfannkuch, Lennart [Verfasser]. "Human beta defensin 3 induction in gastric epithelial cells under Helicobacter pylori infection and cytokine dependent modulation / Lennart Pfannkuch". Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2014. http://d-nb.info/1056907878/34.
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Stefanello, Vanessa Felix Vaz. "Antagonismo a Colletotrichum lindemuthianum e ativação de mecanismos de defesa em feijoeiro-comum desencadeados por Trichoderma spp". Universidade Estadual do Oeste do Paraná, 2015. http://tede.unioeste.br:8080/tede/handle/tede/1295.
Abstract (sommario):
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Previous issue date: 2015-08-24Conselho Nacional de Desenvolvimento Científico e Tecnológico
The objective of the work was to evaluate the action of Trichoderma spp. and its filtered as biocontrol agent of anthracnose and resistance inducer in beans. Were conducted two experiments in vitro, where were made a germination test of Colletotrichum lindemuthianum conidium after the treatment with Trichoderma spp. filtered, and the direct confrontation test of 21 cultures isolated from Trichoderma spp. agains this pathogen were also conducted two experiments in vivo: on the first imposed treatments in base of Trichoderma in the beans inoculated via seed; on the second experiment the treatments aplication were made through foliar spray of filtered medium of Trichoderma spp. For the experiments in vivo were realized sheets collects for biochemical analysis, in which there were two collects for the experimente that were treated via seed (15 days after the foliar emergency and three days after the pathogen inoculation). Whereas for the experiment which the treatments were via foliar spray of filtered medium of Trichoderma, were realized three collectings, (the first without the treatment aplication, the second three days after the filtered pulverization and the third collect realized three days after the pathogen inoculation). Were determined the polyphenoloxidase activity (PFO), peroxidase (POX) and phenylalanine ammonia lyase (FAL), and were evaluated the total protein content, total phenols, lignin and the severity of anthracnose after treatments in base of Trichoderma for both experiments. For the germination test of C. lindemuthianum, conidium the filtered from the isolated TM1, TI1 and TOD1 reduced the germination in, 33%, 38% and 61% respectivily. In direct confrontation were realized that the isolated inhibited pathogen growth. For the PFO activity in via seed treatment, the isolated TLB12, TOD1 and TOD2B caused an increase thereof after challenge with the pathogen, while the treatment via foliar spray of Trichoderma filtered were not observed significant difference. The POX activity in beans treated at sowing, for the time 1 weren‟t observed difference between the treatments, whereas in the time 2 some isolated tended to suppress the enzymatic activity, while for plants treated via foliar pulverization notes the tendency to enzymatic suppression of POX in time 2 caused by some filtered in relation to the positive control. The FAL enzymatic activity and the total soluble protein contents both in the aplication of the treatments via seed and via foliar pulverization in beans didn‟t result in significant difference. For the total phenol contents and lignin the treatments in base of Trichoderma via sowing and via foliar pulverization didn‟t promote an icrease of the same in beans. The severity in treated beans presented in general low, making these inaccurate data
O objetivo do trabalho foi avaliar a ação do Trichoderma spp. e seus filtrados como agente de biocontrole da antracnose e indutor de resistência em feijoeiro. Conduziram-se dois experimentos in vitro, onde foi realizado teste de germinação de conídios de Colletotrichum lindemuthianum após tratamento com filtrados de Trichoderma spp., e o teste de confronto direto de culturas de 21 isolados de Trichoderma spp. frente a esse patógeno também conduziu-se dois experimentos in vivo: no primeiro se impôs os tratamentos a base de Trichoderma no feijoeiro inoculado via semente; já no segundo experimento a aplicação dos tratamentos se deu por meio de pulverização foliar de filtrados de Trichoderma spp. Para os experimentos in vivo realizaram-se coletas de folhas para análises bioquímicas, no qual houve duas coletas para o experimento cujos tratamentos foram via semente (aos 15 dias após a emergência foliar e três dias após a inoculação do patógeno). Já para o experimento aos quais os tratamentos foram via pulverização foliar de filtrados de Trichoderma, realizaram-se três coletas, (a primeira sem a aplicação do tratamento, a segunda realizada três dias após a pulverização dos filtrados e a terceira coleta realizada três dias após a inoculação do patógeno). Determinou-se a atividade de polifenoloxidase (PFO), peroxidase (POX) e fenilalanina amônia-liase (FAL), e foram avaliados os teores de proteínas totais, fenóis totais, lignina e a severidade da antracnose após os tratamentos a base de Trichoderma para ambos os experimentos. Para o teste de germinação de conídios de C. lindemuthianum, os filtrados dos isolados TM1, TI1 e TOD1 reduziram a germinação em, 33%, 38% e 61% respectivamente. No confronto direto percebeu-se que os isolados inibiram o crescimento do patógeno. Para a atividade de PFO em tratamentos via semente, os isolados TLB12, TOD1 e TOD2B causaram aumento da mesma após o desafio com o patógeno, enquanto que no tratamento via pulverização foliar de filtrados de Trichoderma não foi observada diferença significativa. A atividade de POX em feijoeiro tratado na semeadura, para o tempo 1 não observou-se diferença entre os tratamentos, já no tempo 2 alguns isolados tenderam a suprimir a atividade enzimática, enquanto que para as plantas tratadas via pulverização foliar nota-se tendência de supressão enzimática da POX no tempo 2 ocasionada por alguns filtrados em relação ao controle positivo. A atividade enzimática de FAL e os teores de proteínas solúveis totais tanto na aplicação dos tratamentos via semente quanto via pulverização foliar em feijoeiro não acarretou em diferença significativa. Para os teores de fenóis totais e de lignina os tratamentos a base de Trichoderma via semeadura e via pulverização foliar não promoveram incremento dos mesmos em feijoeiro. Já a severidade em feijoeiro tratado apresentou-se no geral baixa, tornando estes dados imprecisos
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Trevisoli, Edilaine Della Valentina Gonçalves. "Purificação de eliciadores de defesa vegetal em soja e feijoeiro a partir de nematoides fitopatogênicos". Universidade Estadual do Oeste do Paraná, 2016. http://tede.unioeste.br:8080/tede/handle/tede/1475.
Abstract (sommario):
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Previous issue date: 2016-02-25Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
The induction of resistance in plants to pathogens is an alternative method of disease control, wich involves activation of plant resistance mechanisms such as induction of phytoalexins. The elicitors molecules are able to induce and activate those responses, and therefore, techniques have sought to isolate and characterize fractions with elicitor character. The study aimed to purify, through ion exchange chromatography and gel filtration chromatography, eliciting molecules from pathogenic nematodes, and test them in phaseolin induction in beans hypocotyls beans and gliceolin in soybean cotyledons. The buffer solution Tris HCl 0.05 M (pH 6.8) was used as control and the acibenzolar-S-methyl (50 mg a.i. L-1) and Saccharomyces cerevisiae (20 mg mL-1) were used as induction standard treatments. Ion exchange chromatography (IEC) and gel filtration chromatography (GC) were performed to separate fractions with eliciting power from 500 female nematodes of Meloidogyne incognita and Meloidogyne javanica. For purification of elicitors from Meloidogyne javanica, through IEC, six glycidic fractions and six glycoproteins were obtained. These were purified on GC, obtaining sixty-three fractions. They have been classified according to their nature, as twenty-six glycidic and thirty-seven glycoprotein with molecular weights ranging from 29.19 to 2989.25 kDa. Regarding the elicitors purification of Meloidogyne incognita through IEC, nine glycidic and five glycoprotein fractions were obtained. From these fractions, a total of fifty-eight fractions was obtained through GC, twenty-five glycidic and thirty-three glycoprotein with molecular weights ranging from 37.42 to 200.32 kDa. From the fractions purified from Meloidogyne javanica eight had inducing potential of phaseolin. For gliceolin fifteen fractions showed inducing effect. Regarding the fractions purified from Meloidogyne incognita, no fraction has inductive potential of phaseolin superior to the standard treatment. However, twenty-two fractions suppressed phytoalexin inducing activity. For gliceolin ten fractions induced the same, whereas, twenty-three fractions suppressed the induction of gliceolin. Chromatography was efficient in the purification of elicitors compounds. Compounds with suppressing characteristics of gliceolin and phaseolin were checked in bioassays. For those fractions obtained through IEC, and then submitted to GC that did not induce phytoalexin, it is suggested that molecules need to act together to have elicitor effect and thus induce defense response in the plant
A indução de resistência em plantas contra patógenos é um método de controle alternativo de doenças, e que envolve a ativação dos mecanismos de resistência da planta, como a indução de fitoalexinas. As moléculas eliciadoras possuem a capacidade de induzir e ativar tais repostas, e assim sendo, técnicas têm buscado isolar e caracterizar frações com caráter eliciador. O trabalho teve por objetivo purificar, por cromatografia de troca iônica cromatografia de filtração em gel, moléculas eliciadoras a partir de nematoides fitopatogênicos, e testá-las na indução de faseolina em hipocótilos de feijoeiro e gliceolina em cotilédones de soja. O tampão Tris HCl 0,05 M (pH 6,8) foi utilizado como tratamento controle e o acibenzolar-S-metil (50 mg i.a. L-1) e o Saccharomyces cerevisiae (20 mg mL-1) foram utilizados como tratamento padrão de indução. Cromatografia de troca iônica (CTI) e cromatografia de filtração em gel (CFG) foram realizadas para separar frações com poder eliciador a partir de quinhentas fêmeas de nematoides de Meloidogyne incognita e Meloidogyne javanica. Para a purificação de eliciadores a patir de Meloidogyne javanica, por CTI, foram obtidos seis frações glicídicas e seis glicoproteicas. Estas, por sua vez, foram purificadas em CFG, sendo obtidos no total sessenta e três frações. As mesmas foram classificadas de acordo com sua natureza, sendo vinte e seis glicídicas e trinta e sete glicoproteicas, com massas moleculares variando de 29,19 a 2.989,25 kDa. Em relação a purificação de eliciadores de Meloidogyne incognita por CTI, foram obtidos nove frações glicídicas e cinco glicoproteicas. A partir destas, foram obtidos por CFG um total de cinquenta e oito frações, sendo vinte e cinco glicídicas e trinta e três glicoproteicas, com massas moleculares variando de 37,42 a 200,32 kDa. Das frações purificadas a partir de Meloidogyne javanica oito apresentaram potencial indutor de faseolina. Para gliceolina quinze frações mostraram efeito indutor. Em relação as frações purificadas a partir de Meloidogyne incognita, nenhuma fração apresentou potencial indutor de faseolina superior ao tratamento padrão. Entretanto, vinte e duas frações suprimiram a atividade de indução de fitoalexina. Para gliceolina dez frações induziram a mesma, enquanto que, vinte e três frações suprimiram a indução da gliceolina. A cromatografia foi eficiente na purificação de compostos eliciadores. Compostos com características supressoras de gliceolina e faseolina foram verificadas nos bioensaios. Para aquelas frações obtidas por CTI e posteriormente submetidas a CFG que não induziram fitoalexina, sugere-se que as moléculas necessitam atuar juntas para haver efeito eliciador e assim induzir a resposta de defesa no vegetal
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Meinerz, Cristiane Claudia. "Indução de mecanismos bioquímicos de defesa em sorgo (Sorghum bicolor) por frações obtidas do decocto de avenca (Adiantum capillus-veneris)". Universidade Estadual do Oeste do Paraná, 2010. http://tede.unioeste.br:8080/tede/handle/tede/1413.
Abstract (sommario):
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Previous issue date: 2010-02-24Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Induction of resistance involves the activation of plant defense mechanisms in response to treatment with biotic or abiotic elicitors. The application of plant extracts in order to induce resistance mechanisms is an interesting alternative to chemical control, however, besides the presence of inducers, can occur the presence of suppressors. This study aimed to partially purificate through gel filtration chromatography (GFC) and precipitation with ammonium sulfate (SA), compounds present in decoct of Adiantum capillus-veneris, capable to induce defense mechanisms in sorghum mesocotyls, including phytoalexins and peroxidase, polyphenoloxidase (PPO), phenylalanine ammonia-lyase (PAL) and chitinase. The decoct 1% was fractionated with concentrations of ammonium sulfate, 0-20%, 20-40%, 40-60%, 60-80% and 80-100% of SA and those fractions were subjected to GFC. We obtained nine protein peaks and one glucosic peak for decoct with molecular weights ranging from 0.61 to 0.01 KDa; to fraction 0-20% were obtained two protein and two glucosic peaks, with molecular weights lower than 0.01 KDa, and concentration of sugars ranging from 4.1 to 17.5 mg mL-1; to fraction 20-40% were obtained three protein peaks (0.98 to 111.5 KDa) and five glucosic peaks (11.3 to 73.7 mg mL-1); to fraction 40-60% were obtained two protein peaks (0.09 to 111.5 KDa) and two glucosic peaks (5.6 to 7.5 mg mL-1); to fraction 60-80% were obtained six protein peaks (lower than 0.02 KDa) and two glucosic peaks (16.5 to 51.3 mg mL-1); and to fraction 80-100% were obtained three protein peaks (lower than 0.09 KDa). Sorghum mesocotyl were treated with fractions from the GFC, and decoct, acibenzolar-S-methyl (ASM) (125 mg L-1 of a. i. as elicitor of reference) and sodium phosphate buffer 10 mM pH 6.0. After incubation of 96 h were measured the levels of phytoalexins in mesocotyls and the activity of defense-related enzymes in leaves. Treatment with peak II (0,09 KDa) induced phytoalexin 6.68% more than. Among the fractionn, 60-80% increased 76% compared to ASM. To peroxidase the peak IV (lower than 0,01 KDa) increased 21% the activity compared to control water, and 44% compared to ASM. For the fraction 0-20% the protein peak II (lower than 0,01 KDa) increased 39% the activity in relation to the fraction 0-20% and 19% in relation to decoct. The fraction, 80-100% increased 89% compared to, ASM. For the PPO the peak VI (lower than 0,01 KDa) from decoct decreased 88% the activity compared to ASM. For PAL the peak II (lower than 0,01 KDa) from fraction 0-20% was 91% higher than decoct. For chitinase 1% peak IV (lower than 0,01 KDa) from decoct was 68% higher than the ASM. It was possible to induce defense mechanisms in sorghum by the application of partially purified fractions from A. capillus-veneris, which can allow to obtain new molecules and development alternative methods to control plant diseases
A indução de resistência envolve a ativação de mecanismos de defesa latentes existentes nas plantas em resposta ao tratamento com agentes bióticos ou abióticos. A aplicação de extratos vegetais visando à indução de mecanismos de resistência é uma alternativa interessante ao controle químico, entretanto, nestes extratos pode ocorrer além da presença de indutores, a presença de supressores. Este trabalho teve por objetivo a purificação parcial, por meio de cromatografia de filtração em gel (CFG) e precipitação com sulfato de amônio (SA), de compostos presentes em decocto de avenca (Adiantum capillus-veneris), eficientes na indução de mecanismos de defesa em mesocótilos de sorgo, incluindo as fitoalexina deoxiantocianidinas e as proteínas peroxidase, polifenoloxidase, fenilalanina amônia-liase e quitinase, buscando selecionar frações potencialmente eficientes na indução de resistência em plantas. Decocto (EA 1%) de A. capillus-veneris foi fracionado com concentrações de sulfato de amônio de 0-20%, 20-40%, 40-60%, 60-80% e 80-100% e esses cortes foram submetidos à cromatografia de filtração em gel (CFG). Foram obtidos nove picos protéicos e um pico glicídico para EA 1% com massas moleculares variando de 0,61 à 0,01 KDa; no corte 0-20% foram obtidos dois picos protéicos e dois glicídicos, com massas moleculares menores que 0,01 KDa, e concentração de açúcares redutores variando de 4,1 a 17,5 µg mL-1; no corte 20-40% três picos protéicos (111,5 à 0,98 KDa) e cinco glicídicos (11,3 a 73,7 µg mL-1 de açúcares); no corte 40-60% dois picos protéicos (111,5 à 0,09 KDa) e dois glicídicos (5,6 a 7,5 µg mL-1); no corte 60-80% seis picos protéicos (menor que 0,02 KDa) e dois glicídicos (16,5 a 51,3 µg mL-1); e no corte 80-100% três picos protéicos (menor que 0,09 KDa). Mesocótilos de sorgo foram tratados com as frações provenientes da CFG, além do decocto a 1%, acibenzolar-S-metil (ASM) (125 mg. L-1 do i.a. como elicitor de referência) e tampão fosfato de sódio 10 mM pH 6,0, totalizando 42 tratamentos. Após incubação por um período de 96 h, avaliou-se dos teores de fitoalexinas nos mesocótilos e análises bioquímicas dos folíolos. O tratamento pico II (0,09 KDa) do EA 1% mostrou-se eficiente na indução de fitoalexinas, sendo superior em 6,68% ao ASM. Entre os cortes, 60-80% permitiu incremento de 76% em relação ao ASM. Para peroxidase o pico IV (menor que 0,01 KDa) do EA 1% incrementou 21% a atividade em relação a testemunha água e 44% ao ASM. Para os precipitados 0-20% o pico protéico II (menor que 0,01 KDa) promoveu incremento de 39% na atividade em relação ao corte 0-20% e 19% para o EA 1%. O precipitado 80-100% foi superior 89% ao ASM. Para polifenoloxidase o pico protéico VI (menor que 0,01 KDa) do EA1% reduziu 88% a atividade em relação ao ASM. Para fenilalanina amônia-liase o pico protéico II (menor que 0,01 KDa) do corte 0-20% foi 91% superior ao EA 1%. Para quitinase o pico protéico IV (menor que 0,01 KDa) do EA 1% foi 68% superior ao ASM. Foi possível induzir mecanismos de defesa em sorgo pela aplicação de frações parcialmente purificadas de A. capillus-veneris, o que pode permitir a obtenção de novas moléculas e o desenvolvimento de métodos alternativos para controle de doenças em plantas
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Tayeh, Christine. "Induction de résistances chez le blé (Triticum aestivum L.) lors d’une interaction compatible avec Blumeria graminis (DC. E.O Speer) : mécanismes mis en jeu après applications de tréhalose et d’heptanoyl d’acide licylique, dérivé fonctionnalisé de l’acide salicylique". Thesis, Littoral, 2012. http://www.theses.fr/2012DUNK0521.
Abstract (sommario):
L’utilisation de molécules stimulatrices des défenses des plantes (SDP), également appelées inducteurs de résistance, constitue une alternative potentielle aux traitements fongicides conventionnels pour combattre les maladies dues à des champignons phytopathogènes. Trois SDPs, le tréhalose (TR), l’acide salicylique (SA) et l’heptanoyl d’acide salicylique (HSA), un dérivé fonctionnel du SA, protègent le blé (Triticum aestivum L.) contre l’oïdium (Blumeria graminis f.sp. tritici), lorsqu’ils sont utilisés de façon préventive. La protection obtenue n’est pas liée à un effet fongistatique direct sur la germination des spores du champignon, mais à l’induction chez le blé de défenses qui diminuent le développement de la maladie. Notre travail consistait à caractériser les mécanismes de défense mis en jeu après applications foliaires de TR, de HSA et de SA chez un cultivar de blé sensible à l’oïdium. Un suivi de l’expression de gènes marqueurs de défense, réalisé par RTqPCR, a été mené en cinétique,depuis le traitement par les SDPs jusqu'à 4 jours après infection. Les activités enzymatiques correspondantes ont été également mesurées, et l’influence indirecte des SPDs sur le processus infectieux a été observé en microscopie in planta. Ainsi, les réactions de défense déclenchées par le TR, le SA et le HSA ralentissent l’évolution de l’infection, jouant respectivement sur la germination des conidies, structures infectieuses de Bgt, sur la germination du tube germinatif appressorial (AGT) et sur la proportion d’AGTs qui parviennent à pénétrer dans les tissus foliaires. Le TR est à l’origine d’une augmentation de l’expression des gènes codant pour une lipoxygénase, une protéine de transfert des lipides et une phospholipase C, impliquées dans le métabolisme lipidique et la signalisation, et de gènes codant pour des protéines PR comme les chitinases et PR1, tous connus comme marqueurs de défense. Ainsi, les réactions déclenchées par le TR correspondent à un effet inducteur de défenseplutôt qu’à une réaction de stress osmotique. Le HSA modifie particulièrement le métabolisme lipidique, en induisant fortement et pendant toute la cinétique, l’expression du gène codant pour la LOX et l’activité correspondante, aussi bien hors contexte infectieux qu’en contexte infectieux. Cette augmentation de l’activité LOX n’est pas retrouvée chez des feuilles traitées au SA et caractérise donc le HSA. L’importance des réactions observées avec le TR, le SA et le HSA, hors contexte infectieux et en présence de Bgt amène à discuter les effets éliciteurs et potentialisateurs de ces 3 SDPsThe use of plant elicitors, also known as resistance inducers, is an alternative to conventional fungicides to control diseases caused by phytopathogenic fungi. Three resistance inducers, trehalose (TR), salicylic acid (SA) and heptanoyl salicylic acid (HSA), a functional derivative of SA, protect wheat (Triticum aestivum L.) against powdery mildew (Blumeria graminis f . sp. tritici) when applied prior to infection. The protection obtained is not linked to any direct fungistatic effect on the fungal spore germination, but to the induction of wheat defences that impair the development of the disease. Our work aimed at characterizing the defence mechanisms triggered after foliar applications of TR, HSA and SA in a wheat cultivar susceptible to powdery mildew. Monitoring of defence markers genes expression by RTqPCR was conducted during a time-course experiment from the treatment time until 4 days after infection. Corresponding enzyme activities were also measured, and the indirect influence of elicitors on the infectious process was observed by microscopy in planta. Thus, defence responses triggered by TR, SA and HSA slow the progression of the infection, respectively altering the germination of infectious structures such as conidia, the differentiation of appressorial germ tube (AGT) and the proportion of AGTs that manage to penetrate the epidermis. TR causes an increase in the expression of genes encoding a lipoxygenase, a lipid transfer protein and a phospholipase C, which are involved in lipid metabolism and signaling, and genes encoding for PR-proteins such as chitinases and PR1, all known as markers of defence. Thus, the reactions triggered by TR match with the ones triggered during induced defence rather than during osmotic stress response. HSA specifically targeted lipid metabolism, inducing strongly and throughout the time-course, the expression ofthe gene encoding LOX and the corresponding enzyme activity, both in infectious and non-infectious contexts. This increase in LOX activity was not found in leaves treated with SA and thus characterizes HSA mode of action. The importance of the reactions observed with TR, SA and HSA, in non-infectious conditions and in the presence of Bgt have to be considered regarding either elicitation or potentiation
28
Tayeh, Christine. "Induction de résistances chez le blé (Triticum aestivum L.) lors d’une interaction compatible avec Blumeria graminis (DC. E.O Speer) : mécanismes mis en jeu après applications de tréhalose et d’heptanoyl d’acide licylique, dérivé fonctionnalisé de l’acide salicylique". Electronic Thesis or Diss., Littoral, 2012. http://www.theses.fr/2012DUNK0521.
Abstract (sommario):
L’utilisation de molécules stimulatrices des défenses des plantes (SDP), également appelées inducteurs de résistance, constitue une alternative potentielle aux traitements fongicides conventionnels pour combattre les maladies dues à des champignons phytopathogènes. Trois SDPs, le tréhalose (TR), l’acide salicylique (SA) et l’heptanoyl d’acide salicylique (HSA), un dérivé fonctionnel du SA, protègent le blé (Triticum aestivum L.) contre l’oïdium (Blumeria graminis f.sp. tritici), lorsqu’ils sont utilisés de façon préventive. La protection obtenue n’est pas liée à un effet fongistatique direct sur la germination des spores du champignon, mais à l’induction chez le blé de défenses qui diminuent le développement de la maladie. Notre travail consistait à caractériser les mécanismes de défense mis en jeu après applications foliaires de TR, de HSA et de SA chez un cultivar de blé sensible à l’oïdium. Un suivi de l’expression de gènes marqueurs de défense, réalisé par RTqPCR, a été mené en cinétique,depuis le traitement par les SDPs jusqu'à 4 jours après infection. Les activités enzymatiques correspondantes ont été également mesurées, et l’influence indirecte des SPDs sur le processus infectieux a été observé en microscopie in planta. Ainsi, les réactions de défense déclenchées par le TR, le SA et le HSA ralentissent l’évolution de l’infection, jouant respectivement sur la germination des conidies, structures infectieuses de Bgt, sur la germination du tube germinatif appressorial (AGT) et sur la proportion d’AGTs qui parviennent à pénétrer dans les tissus foliaires. Le TR est à l’origine d’une augmentation de l’expression des gènes codant pour une lipoxygénase, une protéine de transfert des lipides et une phospholipase C, impliquées dans le métabolisme lipidique et la signalisation, et de gènes codant pour des protéines PR comme les chitinases et PR1, tous connus comme marqueurs de défense. Ainsi, les réactions déclenchées par le TR correspondent à un effet inducteur de défenseplutôt qu’à une réaction de stress osmotique. Le HSA modifie particulièrement le métabolisme lipidique, en induisant fortement et pendant toute la cinétique, l’expression du gène codant pour la LOX et l’activité correspondante, aussi bien hors contexte infectieux qu’en contexte infectieux. Cette augmentation de l’activité LOX n’est pas retrouvée chez des feuilles traitées au SA et caractérise donc le HSA. L’importance des réactions observées avec le TR, le SA et le HSA, hors contexte infectieux et en présence de Bgt amène à discuter les effets éliciteurs et potentialisateurs de ces 3 SDPsThe use of plant elicitors, also known as resistance inducers, is an alternative to conventional fungicides to control diseases caused by phytopathogenic fungi. Three resistance inducers, trehalose (TR), salicylic acid (SA) and heptanoyl salicylic acid (HSA), a functional derivative of SA, protect wheat (Triticum aestivum L.) against powdery mildew (Blumeria graminis f . sp. tritici) when applied prior to infection. The protection obtained is not linked to any direct fungistatic effect on the fungal spore germination, but to the induction of wheat defences that impair the development of the disease. Our work aimed at characterizing the defence mechanisms triggered after foliar applications of TR, HSA and SA in a wheat cultivar susceptible to powdery mildew. Monitoring of defence markers genes expression by RTqPCR was conducted during a time-course experiment from the treatment time until 4 days after infection. Corresponding enzyme activities were also measured, and the indirect influence of elicitors on the infectious process was observed by microscopy in planta. Thus, defence responses triggered by TR, SA and HSA slow the progression of the infection, respectively altering the germination of infectious structures such as conidia, the differentiation of appressorial germ tube (AGT) and the proportion of AGTs that manage to penetrate the epidermis. TR causes an increase in the expression of genes encoding a lipoxygenase, a lipid transfer protein and a phospholipase C, which are involved in lipid metabolism and signaling, and genes encoding for PR-proteins such as chitinases and PR1, all known as markers of defence. Thus, the reactions triggered by TR match with the ones triggered during induced defence rather than during osmotic stress response. HSA specifically targeted lipid metabolism, inducing strongly and throughout the time-course, the expression ofthe gene encoding LOX and the corresponding enzyme activity, both in infectious and non-infectious contexts. This increase in LOX activity was not found in leaves treated with SA and thus characterizes HSA mode of action. The importance of the reactions observed with TR, SA and HSA, in non-infectious conditions and in the presence of Bgt have to be considered regarding either elicitation or potentiation
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GIUDICE, GAETANO. "NEW PLANT BREEDING TECHNIQUES AND PRIMING AS A MULTIPLE LEVEL STRATEGY FOR THE CONTROL OF DOWNY MILDEW INFECTION IN GRAPEVINE". Doctoral thesis, Università degli Studi di Milano, 2022. http://hdl.handle.net/2434/924372.
Abstract (sommario):
La presente tesi riguarda tre approcci complementari per un controllo più sostenibile del patogeno Plasmopara viticola: cisgenesi, RNAi e priming di difesa delle piante. Nel primo capitolo viene presentata una breve introduzione generale, toccando i principali aspetti relativi alla viticoltura in Europa, alle caratteristiche della malattia, alle nuove strategie biotecnologiche e al priming nella difesa delle piante. Nel secondo capitolo viene presentata una review che descrive in dettaglio i più recenti approcci biotecnologici per la protezione delle colture, tra cui la cisgenesi, l'editing del genoma, l'RNAi e l'epigenetica. Nel terzo capitolo sono riportate le attività relative alla cisgenesi per l’introduzione della resistenza alla peronospora nella vite, lo studio si è concentrato inizialmente sull'induzione dell'embriogenesi somatica in germoplasma d'élite, ottimizzando la coltivazione dei tessuti floreali per la generazione di calli embriogenici. I geni di resistenza TNL2a e TNL2b appartenenti al locus RPV3-1, che conferiscono resistenza a Plasmopara viticola, sono stati quindi selezionati per lo sviluppo di varietà cisgeniche, con la costruzione di un vettore cisgenico che ospita questi due geni. Viene quindi descritta la trasformazione dei calli embriogenici con i ceppi ingegnerizzati di Agrobacterium tumefaciens e le future attività per la rigenerazione di piante cisgeniche trasformate.
Nel quarto e nel quinto capitolo vengono presentati due articoli che affrontano diversi aspetti legati allo sfruttamento del sistema immunitario delle piante: il primo studio mira a chiarire gli effetti del priming indotto da micorrize sul bilancio tra crescita e difesa nella vite mentre il secondo studio si concentra sull'utilizzo di protocolli di protezione alternativi per il controllo della peronospora in un vigneto commerciale. In particolare, nel quarto capitolo “Mycorrhizal symbiosis balances rootstock-mediated growth-defence tradeoffs”, sono stati valutati i potenziali benefici di un inoculo formato da due specie di micorrize arbuscolari, con o senza aggiunta di monosaccaridi, su giovani barbatelle innestate sui portainnesti 1103P e SO4. L'influenza dei diversi trattamenti è stata valutata combinando l'analisi delle caratteristiche agronomiche con tecniche biochimiche e molecolari. I risultati hanno mostrato che, nonostante il comportamento opposto dei due portainnesti selezionati, nei campioni trattati con le micorrize l'intero microbioma della radice è attivamente coinvolto nel bilanciamento dei costi/benefici tra crescita e difesa.
Infine, nel quinto capitolo, viene presentato l’articolo "Novel Sustainable Strategy to control Plasmopara viticola in grapevine, unveil new insights on priming responses and artropods ecology". Lo studio affronta la riduzione del consumo di fungicidi in viticoltura e dei rischi associati attraverso lo sfruttamento di protocolli alternativi per il controllo della peronospora nella vite confrontandoli con un protocollo di protezione standard adottato da una cantina commerciale. Nel primo protocollo sono stati utilizzati solo induttori di resistenza, mentre il secondo e il terzo protocollo hanno seguito il protocollo standard ma sostituendo i fosfonati con anidride fosforica ed estratto di Ecklonia maxima. I risultati hanno mostrato che all'invaiatura l'incidenza e la gravità della peronospora in tutti i protocolli testati erano significativamente ridotte rispetto ai controlli non trattati sia sulla chioma che sui grappoli. Lo studio ha anche mostrato degli spunti interessanti sulla rimodulazione dell'acido salicilico e dell'acido jasmonico nei due protocolli per la sostituzione dei fosfiti. È interessante notare come gli induttori di resistenza attivando le difese della pianta abbiano indotto anche un breve ritardo nella maturazione dei grappoli, agendo, sul metabolismo dei carboidrati, sulla regolazione dei geni di difesa, sulla risposta sistemica acquisita e sulla disintossicazione dalle specie reattive dell’ossigeno. Nella conclusione sono quindi riassunti i principali risultati di ciascun capitolo, esaminandone gli aspetti più critici, inclusa una breve discussione delle attività preliminari che sono state condotte sull’uso dell’RNAi per il silenziamento di due geni essenziali di Plasmopara viticola.The present thesis relates on three complementary approaches for a more sustainable control of Plasmopara viticola: cisgenesis, RNAi and plant defence priming. A brief general introduction is presented in the first chapter, touching the main aspects relative to viticulture in Europe, characteristics of the disease, new biotechnological strategies and priming of plant defence. The second chapter consists of a review article describing with detail the most recent biotechnological approaches for crop protection, including cisgenesis, genome editing, RNAi and epigenetics. In the third chapter the activities concerning cisgenesis for grapevine downy mildew resistance are reported, the study initially focuses on the induction of somatic embryogenesis from elite germplasm, optimising the cultivation of floral tissues for the generation of embryogenic calli. The resistance genes TNL2a and TNL2b belonging to the RPV3-1 locus, which confers resistance to Plasmopara viticola, were then selected for the development of cisgenic varieties, with the construction of a cisgenic vector harbouring those two genes. Finally, the chapter reports on the Agrobacterium tumefaciens transformation of embryogenic calli that are currently cultivated on selective medium, and on the future activities for the regeneration of transformed cisgenic plants. In the fourth and fifth chapters, two papers addressing different aspects related to the exploitation of plant immune system are presented: the first study aimed at clarifying the effects of arbuscular mycorrhiza priming on the grapevine growth-defence trade-off while the second study was focused on the use of alternative protection protocols for the control of downy mildew in a commercial vineyard. Particularly, in the fourth chapter “Mycorrhizal symbiosis balances rootstock-mediated growth-defence tradeoffs”, the potential benefits of an inoculum formed by two arbuscular mycorrhiza fungal species, with or without a monosaccharide addition, were evaluated on young grapevine cuttings grafted onto 1103P and SO4 rootstocks. The influence of the different treatments was assessed by combining the analysis of agronomic features with biochemical and molecular techniques. The results showed that despite the opposite behaviour of the two selected rootstocks, in mycorrhized samples the whole root microbiome is actively involved in the growth-defence trade off balance. Finally in the fifth chapter the submitted paper “Novel sustainable strategies to control Plasmopara viticola in grapevine unveil new insights on priming responses and arthropods ecology” is presented. The study addresses the reduction of fungicide consumption in viticulture and its associated risks by the exploitation of alternative protocols for the control of downy mildew infection in grapevine, compared to a standard winery protection protocol. In the first protocol, only resistance inducers were used, while the second and third protocols followed the standard protocol but substituting phosphonates with phosphorus pentoxide and Ecklonia maxima extract. The results showed that, at véraison, downy mildew incidence and severity were significantly reduced on both canopy and bunches in the plants treated with all tested protocols compared to non-treated controls. The study also revealed interesting insights about the direct effect of protocols for phosphite substitution on the crosstalk between salicylic and jasmonic acid signalling pathways. Interestingly, by priming plant defences, the resistance inducers caused a short delay in bunch ripening, involving changes in carbohydrate metabolism, regulation of defence related genes, systemic acquired resistance and reactive oxygen species detoxification. In the thesis conclusion, the main findings are then summarised for each chapter, by examining the most critical aspects and including a brief discussion on the preliminary activities that were conducted to exploit the RNAi technique for silencing two essential genes of Plasmopara viticola.
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Zwiegelaar, Michele. "DDRT-PCR analysis of defense-related gene induction in cotton". Thesis, 2008. http://hdl.handle.net/10210/434.
Abstract (sommario):
Plants have evolved mechanisms to defend themselves against pathogen attack. These defense mechanisms consist of a series of inducible responses (including specific recognition of pathogen invasion, signal transduction and defense gene activation) that result in resistance. Plants responses to pathogen invasion also result in the suppression of various housekeeping activities of the cells, thus diverting the cellular resources to defense responses. Systemic acquired resistance (SAR), an inducible defense response enhanced as a result of initial infection with a necrotising pathogen, lead to long-term resistance in a plant. Differential gene expression of genes related to defense in cultured cotton cells and leaf disks that have been challenged with a purified elicitor from Verticillium dahliae, as well as a chemical inducer of defense responses, DL-b-amino-n-butyric acid, were investigated. The mRNA differential display reverse transcriptase polymerase chain reaction (DDRT-PCR) was used to identify differentially expressed genes 5 h after application of either 50 mg mL-1 Verticillium dahliae elicitor or 1 mM DL-b-amino-n-butyric acid to cotton cell suspension cultures and leaf disks. Identified cDNAs up- or down-regulated for this study were classified into seven groups: ‘Transcription factor’, ‘Ubiquitin and Proteasome’, ‘Mitochondria’, ‘Protein kinase/Receptor-like kinase’, ‘Defense/Resistance’, ‘Carbohydrate metabolism/Cell wall’ and ‘Other’. The identified cDNAs up-regulated after Verticillium dahliae elicitor treatment, classified in the ‘Transcription factor’ group, coded for a MYB family transcription factor, zinc finger protein and a RMA1 RING zinc finger protein. The identified cDNA classified in the ‘Mitochondria’ group coded for a cytochrome C oxidase subunit I and II and the cDNA classified in the ‘Protein kinase/Receptor-like kinase’ group coded for a serine/threonine protein kinase. The identified cDNA classified in the ‘Defense/Resistance’ group coded for a disease resistance protein family and the cDNAs classified in the ‘Carbohydrate metabolism/Cell wall’ group coded for a beta-1,4-Nacetylglucosaminyltransferase, a cellulose synthase-like protein, a 3-deoxy-D-manno-octulosonic acid transferase-like protein and a hydroxyproline-rich glycoprotein homolog. In addition, a cDNA classified in the ‘Other’ group, coded for a urea active transporter-like protein. The cDNA identified that was down-regulated after Verticillium dahliae elicitor treatment, classified in the ‘Carbohydrate metabolism/Cell wall’ group, coded for a proline-rich protein family and cDNAs classified in the ‘Other’ group coded for a thioredoxin reductase1 and ‘hookless1’ homologue. Among the identified cDNAs up-regulated after DL-b-amino-n-butyric acid treatment, classified in the ‘Ubiquitin and Proteasome’ group, were a 20S proteasome subunit alpha type 5 and an ubiquitin. The identified cDNA classified in the ‘Mitochondria’ group coded for a NADH dehydrogenase subunit 6, a mitochondrial DNA product. The identified cDNAs classified in the ‘Other’ group coded for an armadillo repeat containing protein and a phosphoinositide-specific phospholipase C. The cDNA identified that was down-regulated after DL-b-amino-n-butyric acid treatment, classified in the ‘Protein kinase/Receptor-like kinase’ group, coded for a casein kinase I like protein. The identified cDNA classified in the ‘Carbohydrate metabolism/Cell wall’ group, coded for a putative glycine rich protein. Also, the identified cDNA classified in the ‘Other’ group, coded for a NADH dehydrogenase subunit F that is coded for by chloroplast DNA. The differential expression of the cDNAs up-regulated after the Verticillium dahliae elicitor treatment was confirmed for seven of the nine cDNA clones with a Reverse Northern dot blot. Also, the differential expression of two cDNAs up-regulated after DL-b-amino-n-butyric acid treatment was confirmed and the induction kinetics was followed with a Reverse Northern dot blot. The mRNAs corresponding to C8B5, the gene encoding an ubiquitin, were detectable after 2.5 h and showed a significant increase in expression up to 7.5 h, after which the expression levels decreased to levels similar to those detected at 2.5 h. The mRNAs corresponding to L4B4, a homologue of an a-type subunit of 20S proteasome, were detectable after 2.5 h with an gradual increase in expression levels up to 7.5 h after which the expression levels decreased to levels similar to those detected at 2.5 h. This study facilitated a better understanding of differential gene regulation during triggering of defense responses in cotton following elicitation with the Verticillium dahliae elicitor and DL-b-aminon- butyric acid.Prof. I.A. Dubery
31
Yang, I.-Chih, e 楊鎰誌. "Analysis of AvrPtoBB728a domains required for the induction of tomato defense responses". Thesis, 2019. http://ndltd.ncl.edu.tw/handle/8k7c52.
Abstract (sommario):
碩士國立臺灣大學
農業化學研究所
107
Pseudomonas syringae pv. tomato (Pst) DC3000 is the causing agent of tomato bacterial speck disease, and also one of the model organisms for studying the interactions between phytopathogenic bacteria and their hosts. Similar to the other phytopathogenic bacteria, Pst DC3000 can also translocate effector proteins into its host cells via the type III secretion system, to interfere with defense responses and/or normal physiological/-metabolic pathways, leading to symptoms development on host plants. AvrPtoB is a type III secretion effector identified in Pst DC3000. In addition to the virulence activities mentioned above, AvrPtoB can also be recognized by the resistant protein Pto and triggers a hypersensitive response (HR). Previous studies have shown that the sequence of avrPtoB is widely present in Pseudomonas syringae, in which a homolog of AvrPtoB from a bean pathogen P. s. pv. syringae (Psy) B728a (hereafter AvrPtoBB728a), can also induced HR on cultivate tomato lacking Pto. This response is related to the Pto gene family members as determined by gene silencing analysis. The purpose of this study was to confirm the resistant (R) protein(s) responsible for recognizing AvrPtoBB728a to induce resistance responses in cultivate tomato. In addition, the region of AvrPtoBB728a required for interaction with the cognate resistant protein was also determined. The N- or C-terminal truncations of AvrPtoBB728a were constructed for yeast two-hybrid analysis as well as pathogenicity or HR test. The results demonstrated that SlPtoB, which can recognize only AvrPtoBB728a, but not AvrPtoB728a or AvrPtoB, is indeed the corresponding R protein for AvrPtoBB728a-induced resistance in cultivate tomato. The smallest region of AvrPtoBB728a required for SlPtoB recognition is amino acids 111–330. When tomato cultivar Rio-Grande PtoR was substituted for the pathogenicity assay, the fragment of AvrPtoBB728a sufficient for triggering Pto-mediated resistance could be amino acids 111–215. Amino acid sequence alignment of AvrPtoBB728a and AvrPtoB revealed that Pto-interacting domains (PID) of these two effectors are similar. However, AvrPtoBB728a interaction with SlPtoB requires longer fragment equivalent to a region covering the Fen-interacting domain (FID) and PID of AvrPtoB.
32
"HOST defense peptides BMAP-27 and BMAP-28 down-regulate proliferation of T cells through the induction of T cell anergy". Thesis, 2010. http://hdl.handle.net/10388/etd-08252010-145315.
Abstract (sommario):
Host Defense Peptides (HDPs) are small, cationic and amphipathic molecules with inherent antimicrobial and immunomodular function. However their effects on blood-derived T cells is unknown and is the focus of this investigation. In this thesis, porcine peripheral blood mononuclear cells (PBMCs) were stimulated with bovine myeloid antimicrobial peptide (BMAP)-27, BMAP-28, Indolicidin (Indol), or HH2 in the presence and absence of Concanavalin A (ConA). It was observed that BMAP-27, BMAP-28, and Indol inhibited ConA-stimulated porcine PBMC proliferation. To ensure that the observed effect on cell proliferation was not simply due to a physical interaction between the peptide and ConA, addition of peptide and ConA was staggered. Porcine CD4+/CD8+ T cells were isolated from blood using magnetic activating cell sorting (MACS) and it was determined that BMAP-27 and BMAP-28 inhibited ConA-stimulated T cell proliferation. They did not promote T cell necrosis, but approximately 40 % of the activated T cells undergoes apoptosis in the presence of BMAP-27 and BMAP-28. The remaining 60 % of the T cells consumed very little ATP and showed an increase in expression of cytotoxic T lymphocyte antigen-4 (CTLA-4), indicating the induction of T cell anergy. The addition of exogenous IL-2 decreased the surface expression of CTLA-4 in ConA- activated CD4+ T cells and induced renewed CD4+/CD8+ T cell proliferation, an indicator that these cells underwent activation-induced anergy. Thus, we submit that BMAP-27 and BMAP-28 may play a role in returning the activated T cell population to a homeostatic state through induction of peripheral tolerance mechanisms.
33
Zeidler, Dana [Verfasser]. "Activation of nitric oxide synthase and induction of defense genes in Arabidopsis thaliana by bacterial lipopolysaccharides / Dana Zeidler". 2006. http://d-nb.info/978904990/34.
34
Carvalho, Ana Cristina Pontes. "Hormetic induction of antioxidant defenses for promotion of healthy aging". Doctoral thesis, 2017. http://hdl.handle.net/1822/54204.
Abstract (sommario):
Tese de Doutoramento em Biologia Molecular e Ambiental (especialidade em Biologia Celular e Saúde)People are living longer but often suffer from multiple diseases related to aging which has important social and economic implications. Consumption of fruits and vegetables has been associated with reduced risk of age-related diseases but the scientific basis supporting the strategy to improve health through diet is largely missing. The main objective of this doctoral thesis was to clarify if the hormetic induction of cellular stress responses by phytochemicals, in particular the Nrf2/ARE signaling pathway, can provide anti-aging effects and therefore explain the health beneficial effects of consumption of fruits and vegetables. In chapter 2, the extensive available literature on curcumin was reviewed. The ancestral use of turmeric in traditional medicine and the extensive research over the last decades indicate that curcumin is an interesting candidate for interventions to achieve healthy aging. Currently, investigations are being conducted to overcome the limitations of the use of curcumin in aging interventions. In chapter 3, the ability of the phenolic diterpenes carnosic acid (CA) and carnosol (CS) to induce antioxidant defenses in normal human fibroblasts was evaluated and related with anti-aging effects. CA and CS induced antioxidant defenses in human fibroblasts associated with Nrf2 signaling. The stress response elicited by CS conferred a cytoprotective action against a following oxidant challenge with tert-butyl hydroperoxide (t-BOOH), confirming its hormetic effect. CS also protected against H2O2-induced premature senescence and ameliorated several features in cells undergoing replicative senescence in vitro. In chapter 4, the ability of extracts of Hypericum perforatum cells (control HP) and of Hypericum perforatum cells elicited with Agrobacterium tumefaciens (elicited HP) to protect against oxidative stress induced in HepG2 cells was evaluated. The methanolic extract of elicited HP, in contrast to the one from control HP, significantly inhibited t- BOOH-induced cell death, GSH depletion and DNA damage, in pre- and co- incubation regimes. The elicited HP extract significantly induced antioxidant defenses, whereas the extract of control HP did not, and that induction was associated with Nrf2 signaling. Overall, these findings support that phytochemicals can be viewed as a mean to promote healthy aging. In particular, the hormetic induction of stress responses by CS in normal human cells supports its further development for nutraceutical interventions during aging.
As pessoas vivem mais tempo mas muitas vezes sofrem de múltiplas doenças associadas ao envelhecimento, o que tem importantes implicações sociais e económicas. O consumo de frutas e vegetais tem sido associado a um risco reduzido de doenças relacionadas com o envelhecimento, mas a base científica para a estratégia de melhorar a saúde através da dieta ainda não está devidamente fundamentada. O objetivo principal desta tese de doutoramento foi esclarecer se a indução hormética de respostas celulares de stress por fitoquímicos, em particular através da via de sinalização Nrf2/ARE, tem efeitos antienvelhecimento e, nesse sentido, poderá explicar os efeitos benéficos para a saúde do consumo de frutas e vegetais. No capítulo 2, a extensa literatura disponível sobre curcumina foi revista. O uso ancestral de turmérico na medicina tradicional e a extensa investigação nas últimas décadas indicam que a curcumina é um candidato interessante para estratégias que visam alcançar um envelhecimento saudável. Atualmente estão a ser conduzidos estudos para superar as limitações do uso de curcumina em intervenções no envelhecimento. No capítulo 3, avaliou-se a capacidade dos diterpenos fenólicos ácido carnósico (CA) e carnosol (CS) de induzir defesas antioxidantes em fibroblastos humanos normais, o que foi relacionado com efeitos anti-envelhecimento. Ambos os compostos induziram defesas antioxidantes associadas à ativação da sinalização Nrf2. A resposta ao stress provocada pelo CS conferiu uma ação citoprotetora contra um estímulo tóxico posterior induzido pelo terc-butil hidroperóxido (t-BOOH), confirmando o seu efeito hormético. O CS protegeu igualmente contra a senescência prematura induzida por H2O2 e melhorou várias características das células em senescência replicativa in vitro. No capítulo 4, avaliou-se a capacidade de extratos de células de Hypericum perforatum (HP) e de células de Hypericum perforatum elicitadas com Agrobacterium tumefaciens (HP+AT) em proteger contra o stress oxidativo induzido em células HepG2. O extrato HP+AT inibiu significativamente a morte celular, a depleção de GSH e os danos no DNA induzida pelo t-BOOH, nos regimes de pré- e co-incubação. O extrato HP+AT induziu defesas antioxidantes associadas à ativação da sinalização Nrf2. Em conjunto, estes dados sustentam a visão de que os fitoquímicos podem ser considerados um meio para promover um envelhecimento saudável. Em particular, a indução hormética de respostas de stress pelo CS sustentam a importância de estudos posteriores que visem a sua utilização em intervenções no envelhecimento.
The research described in this thesis was financially supported by Fundação para a Ciência e Tecnologia through the PhD grant SFRH/BD/86953/2012
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Chen, Po-Chih, e 陳柏志. "The Study of Inducting Intellectual Capital Concept into Defense Budget Management". Thesis, 2007. http://ndltd.ncl.edu.tw/handle/51307743557255727562.
Abstract (sommario):
碩士國防管理學院
國防財務資源研究所
95
This research regards the defense budget management unit as the research subject. By using Structural Equation Model(SEM), we investigates the relationship between the factors of the intellectual capital of defense budget proformance, and check the influence of intellectual capital and defense budget proformance. The first important capital of intellectual capital connotation the takes the concern of budget management unit is “Human capital” ,and the second one is “Relationship capital” .The recognization of budget management units about intellectual capital and budget proformance has significant difference. This study shows that “Human capital” has significant influence to“Structural capital”and “Relationship capital” and directly effect to budget proformance in the budget management units. It shows that reinforcing the “Human capital” of the budget units is the most directly and effective way to better the proformance. By the mediated effect of budget proformance we find that the path (human capital through structural and relationship capital to affect budget proformance) has significant effect. The human capital accumulation of the budget management units can indirectly through the structural and relationship capital to make postive effect to budget proformance.
36
Lee, Min-Hi [Verfasser]. "Induction and regulation of antiviral defence mechanisms through intracytoplasmic sensors / Min-Hi Lee". 2009. http://d-nb.info/996957928/34.
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Parillo, Rita. "Chestnut green waste "in situ" composting for sustainable forest management: biomass composting monitoring, microbiota dynamics, and plant defence induction". Tesi di dottorato, 2015. http://www.fedoa.unina.it/10377/1/parillo_rita_27.pdf.
Abstract (sommario):
Abstract
The product of the chestnut wood cleaning was placed in aerated static piles, composed directly in the wood and consisting of fresh shoots, chipboard, mowing the undergrowth and leaves and curly dry.
The composting process and mature compost was sampled and characterized for physic-chemical parameters and microbiological composition.
The present doctorate thesis enlightens the composting process of biomass from
chestnut woods handling. Physical, chemical parameters and their interaction with
biological aspects were examined. Bacterial and fungal populations were detected
and characterized during the composting process in order to identify species and
their potential beneficial effects on plants. Agronomic studies were conducted to
evaluate effects of the compost on plant fitness and suppressive activity.
The results of the characterization of the process showed the potential in
agriculture of the mature product.
Main results of the study are:
a) The temperature values in the internal part of the pile were strongly affected
by the seasonal climatic conditions. Averagely, the decomposition process
occurred at low temperature;
b) The agronomic valuations allow the classification of the compost obtained
as a good quality amendant;
c) Parameters analyzed for stability evaluation, respiration test and phytotoxicity
bioassay, as well as sanitary checks, indicated the product absolute
suitability;
d) Parameters of plant fitness and agronomic evaluation showed that plants
grown in compost activate their response to stress;
e) The suppression capability was demonstrated both in vitro and in vivo;
f) The trends of functional populations (cellulose, hemicellulose and lignin)
during the bio-oxidative process were affected by the decrease of activity
water and the temperature;
g) DGGE patterns of eukaryotic populations showed a predominance of
Ascomycota, including species of Penicillium, Moristroma,
Paraconiothyrium, Fusarium, Cladosporium, and Aspergillus. Selected
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prokaryotic bands were affiliated with Bacilli, followed by Actinobacteria,
Flavobacteriia, and -Proteobacteria;
h) Extraction and SEM-TEM characterization of humic substances from wheat
straw co-compost including lignocellulosic fungi and metallic oxides,
reveales the importance of metallic oxides in controlling morphology
stablility of HA-ion aggregates.
This is the first time that the chestnut in situ composting process is characterised in
all the phases. Moreover, this is the first time that the microbial dynamics during
the process as well as the microbial characterization and its suppressive activity on
soil-borne plant pathogens, was investigated.
The results are encouraging and indicate that biomasses from forest and
agricultural origin could represent a new and underspeculated source of agriculture
amendant, pathogen and pests control, income for marginal areas, carbon
sequestration, and biodiversity preservation.
It is advisable that the research will keep on truck investigating the way to
optimize the process to: amplify carbon sequestration, investigate the process in
different matrices, and unravel the transcriptome of the plant stress response
38
Cruz, Joana Maria dos Reis Franco. "Induction of anti-herbivore defences by direct amphipod consumption and water borne grazer cues in macroalgae". Master's thesis, 2007. http://hdl.handle.net/10400.1/266.
Abstract (sommario):
Dissertação mest., Estudos Marinhos e Costeiros, Universidade do Algarve, 2007Serrão, Ester
Herbivores have been repeatedly shown to induce defences in terrestrial plants, but few examples exist from marine macroalgae. In two bio-assayed laboratory experiments we tested the effects of (1) direct amphipod consumption, (2) water borne cues from nearby grazed conspecifics, and (3) water-borne cues from non grazing consumers on the induction of anti-herbivore defences in macroalgae of the southern coast of Portugal. Both the brown alga Fucus vesiculosus and the red alga Sphaerococcus coronopifolius displayed distinct defence regulation. They induced defences when consumers were present and reduced defences again when consumption ceased. A reduction in palatability was considered to be indicative of an alga’s defence mechanism. Defence regulation reacted to consumption stimuli in less than two weeks. For F. vesiculosus we found the defence activity in the lipophilic fraction of the alga’s chemistry. Both algal species induce defences after receiving water-borne signals from nearby grazed conspecifics as well as non-grazing amphipods. These results imply that species of red and brown algae can recognise a suite of cues indicating herbivore pressure, allowing them to adjust their defensive traits in finely tuned short-term responses. Inducible defences may be more common in macroalgae than suspected.
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Pezet, Joshua D. "Resin Volatiles of Eastern Hemlock Induced by its Non-Native Herbivores". 2013. https://scholarworks.umass.edu/theses/976.
Abstract (sommario):
Eastern hemlock (Tsuga canadensis) is in decline because of infestation by the invasive hemlock woolly adelgid (Adelges tsugae; ‘HWA’) and, to a lesser extent, the elongate hemlock scale (Fiorinia externa; ‘EHS’). Many conifers respond to insect herbivory by inducing oleoresin-based defenses, however it is unknown whether eastern hemlock is capable of this inducible response. We conducted a plantation setting study of artificially infested saplings to determine if feeding by HWA or EHS induces changes in the tree’s volatile chemistry. The induced changes in volatiles we found were unlike the terpenoid-based defenses of related conifers. Only HWA feeding elevated methyl salicylate, a plant signal for systemic acquired resistance, and benzyl alcohol, a known antimicrobial and aphid deterrent. The influence of environmental conditions and tree life-stage on hemlock volatile chemistry, potentially important factors for wild hemlock populations, is unknown. We investigated whether mature and immature forest trees respond to HWA infestation with the same patterns of volatile production as plantation saplings in full sun and amended soils. HWA induced volatile changes comparable to those of plantation saplings, with many-fold benzenoid increases and no terpenoid-based resinosis. Nearly all volatiles were substantially more abundant in forest than plantation trees, suggesting the effect of site conditions should be addressed in investigations of mechanisms operative in HWA-resistant biotypes of eastern hemlock. Our findings represent the first important step toward understanding the influence of inducible phytochemical responses on hemlock susceptibility to exotic pests, and highlight the possibility of salicylic acid-dependent biosynthetic activity in this gymnosperm system.