Добірка наукової літератури з теми "Stimulateur des défenses"
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Статті в журналах з теми "Stimulateur des défenses"
Benhamou, Nicole, and Patrice Rey. "Stimulateurs des défenses naturelles des plantes : une nouvelle stratégie phytosanitaire dans un contexte d’écoproduction durable." Article de synthèse 92, no. 1 (September 25, 2012): 24–35. http://dx.doi.org/10.7202/1013299ar.
Повний текст джерелаBenhamou, Nicole, and Patrice Rey. "Stimulateurs des défenses naturelles des plantes : une nouvelle stratégie phytosanitaire dans un contexte d’écoproduction durable." Article de synthèse 92, no. 1 (September 25, 2012): 1–23. http://dx.doi.org/10.7202/1012399ar.
Повний текст джерелаElian, Hubert DieuBéni, Fotso, Astrid Carole Djeuani, Djasbé Mathurin Djamndo, and Ndoumou Denis Omokolo. "Evaluation des activités polyphénoloxydases, peroxydases et l’accumulation des composés phénoliques dans la résistance du manioc stimulé au Benzo (1,2,3) thiadiazol-7-carbothionic acid-s-méthyl ester vis-à-vis de Colletotrichum gloeosporioides Penz." International Journal of Biological and Chemical Sciences 15, no. 3 (September 8, 2021): 950–65. http://dx.doi.org/10.4314/ijbcs.v15i3.9.
Повний текст джерелаДисертації з теми "Stimulateur des défenses"
Kati, Djamel Edine. "Mécanismes de défense chez les végétaux et notion d'élicitation : cas de Cucumis melo et d'un Stimulateur des Défenses Naturelles le «FEN560»." Thesis, Montpellier 2, 2010. http://www.theses.fr/2010MON20007.
Повний текст джерелаThis work is a comparative study between defense mechanisms in melon plant induced by biotic elicitor and treatment by plant extract having simulative proprieties of plant defense mechanisms. The studied pathosystème is Cucumis melo - Fusarium oxysporum fsp melonis. The used plant extract elicitor is named FEN560, it is from fenugreek seeds (Trigonella foenum-graecum). The main works were: 1) Analysis of the enzymatic activities relating to the stress and characterization of PR-proteins sch as peroxidases and chitinases. The lipoxygenase (LOX), the key enzyme of oxylipins biosynthesis and phenylalanine ammonia-lyase, the key enzyme of the phenylpropanoids pathway, were also studyed. 2) The study of the metabolites of the secondary metabolism, in particular accumulation of volatile organic compounds (VOC). 3) A study of expression candidate genes implied in the production of Pr-proteins and the induced resistance pathways is also undertaken. The main results: (i) precocity and intensity of enzymatic activities induction for the two varieties after inoculation of pretreated plants (ii) the priming is generally observed in the site of the second elicitation with a remarkable induction of PR-proteins. (iii) The elicitation induced by FEN560 is systemic; because induction is transmitted between roots and shoots (iv) The modification of VOC emissions coincides with the induction of the LOX activity. It is also noticed the emission of new molecules known for their antibiotic properties or repulsive of the insects herbivorous or attractive of predatory of herbivorous insects. The results on the genes candidates' expression are in general correlated with the enzymatic activities and the production of the volatile organic compounds through LOX activity. In brief, the induction of resistance by the treatment by FEN560 is similar to the phenomenon of "primig" in induced systemic resistance
Jaulneau, Valérie. "Caractérisation moléculaire d'un extrait d'algues vertes, stimulateur des défenses des plantes contre les agents pathogènes." Toulouse 3, 2010. http://thesesups.ups-tlse.fr/2603/.
Повний текст джерелаThe ability of plants to defend themselves against pathogens depends on the perception of elicitors, which induce plant defence. They might be considered as alternative tools for disease control in agronomic crops. Their industrial use needs to identify abundant sources and characterize their activity. Here we report on the identification of a new polysaccharide purified from the green algae Ulva spp. And the characterization of it biological activity in plants. Molecules contained in the extract were sized-fractionated. Analyses of the fractions revealed that biological activity was present only in the fraction of high molecular weight which contained most exclusively a sulfated polysaccharide named ulvan. Response to ulvan were compared to those induced upon methyl jasmonate (MeJA) and acibenzolar-S-methyl on the legume M. Truncatula using microarrays. Interestingly, ulvan gene expression signature showed significant similarity to MeJA and typical responses controlled by the JA pathway, such as induction of protease inhibitor activity. Expression of JA responsive genes, like PDF1. 2, was also induced in A. Thaliana after ulvan treatment. Ulvan provoked an inhibition of in-vitro growth, which was partially impaired in the mutant PEPR2. The efficient protection induced by the crude extract was tested against pathogens on various crops. So, it protect well against oomycetes and fungus that respectively cause downy and powdery mildews. Our results show that ulvan induces plant defences through the jasmonate signalling pathway and highlight the use of functional genomics to develop new bioactive compounds for plant protection
Koçi, Rromir. "Valorisation d'un co-produit d'extraction de l'agar à partir de l'algue rouge Gelidium sesquipedale en tant que stimulateur de défenses de plantes. Caractérisation chimique et évaluation de ses propriétés en vue d'applications en biocontrôle." Electronic Thesis or Diss., Limoges, 2023. http://www.theses.fr/2023LIMO0007.
Повний текст джерелаThe industrial by-products of the first step of agar extraction (from red alga Gelidium sesquipedale) constitute large volumes at SETEXAM company that might be valorized. The objective of this work is to prove that they can be used as elicitor, or plant defense stimulator (PDS). Firstly, the elemental composition of the alkaline by-product revealed a mineral content of 44% (Na, K major components) with heavy metal traces, but under authorized limits. The principal organic components detected are carbohydrates (12.5%) and a fraction rich in floridoside was obtained. This molecule was identified with an original method, through GC-MS. The alkaline by-product, recycled through the industrial process, has its carbohydrate content diminished as the number of cycles increases. These by-products, applied on tomato plants grown in greenhouse under biotic stress, are capable of stimulating defense responses (enzymatic activities, gene expression). The optimal dose (50 mg.L-1) was determined together with the application conditions and time span of responses. In field, the by-products were tested on grapevine and on tomato, for their capacity to reduce downy mildew, or leaf mold symptoms. Promising results were obtained compared to already commercialized elicitors, for moderate disease pressure. The by-product obtained from the first step of industrial agar extraction showed a PDS activity and can be a solution for culture defense allowing a reduction of pesticides for a durable and environmentally friendly agriculture. This work is a base for a homologation file of the product that would transform these by-products from cost to resource for the company
Planchon, Aline. "Le pathosystème Lin (Linum usitatissimum) - Fusarium oxysporum : Impact du champignon et d'un agent de biocontrôle sur des réponses moléculaires de la plante et le développement de la fusariose." Thesis, Normandie, 2018. http://www.theses.fr/2018NORMR122.
Повний текст джерелаIn France, flax (Linum usitatissumum) is a principal fibers crop. Fusarium oxysporum f sp lini (Fol), a soil-borne fungus, is responsible for the major losses in crop yield. PGPR (Plant Growth Promoting Rhizobacteria) are known for their abilities to promote plant growth and health. These bacteria are also good competitors in the rhizosphere and can induce a plant defense response. The use of compounds able to elicit plant defense mechanisms is also an alternative to limit the use of pesticides. In this project, it has been shown that F. oxysporum f. sp. lini induces only two days after inoculation cell wall remodeling in the root and the stem involving hemicelluloses and pectins on two flax varieties, Aramis and Mélina, . The use of the Bacillus subtilis strain ATCC 6633 as biocontrol agent significantly reduced fusarium wilt appearance. In addition to its antifungal effect against Fol, this bacteria is able to induce the expression of two Pathogenesis-Related genes coding for a β-(1,3)-glucanase (PR-2) and a chitinase-like (CTL-10), genes involved in the phenylpropanoid pathway (PHENYLALANINE AMONIA LYASES, PAL-3 and PAL-4) and also in cell wall remodeling (PECTIN METHYLESTERASE-3, PME-3) in the root. Biochemical analyses show that B. subtilis causes modifications resulting in cell wall reinforcement in the stem in both varieties. Finally, the association of B. subtilis with an elicitor (pregnenolone sulfate) had a synergistic effect on the expression of defense-related genes
Jaber, Rim. "Défenses naturelles des plantes : identification de nouveaux stimulateurs de défenses des plantes (SDP) capables d'améliorer la résistance du lin contre le champignon Fusarium oxysporum." Rouen, 2016. http://www.theses.fr/2016ROUES059.
Повний текст джерелаPlants are surrounded by a diverse range of microorganisms that can cause serious crop losses and requires the use of pesticides. Flax is a major crop in Normandy and is regularly challenged by the pathogenic fungus Fusarium oxysporum (Fo) f. Sp. Lini. In order to protect themselves, plants use “innate immunity” called M/PTI (Microbe/Pathogen-Associated Molecular Patterns Triggered Immunity) as a first defense line against pathogens. Plants are able to perceive pathogens by the recognition of conserved motifs on the surface of the pathogens (M/PAMPs), by transmembrane protein receptors (PRRs, Pattern Recognition Receptors). The use of elicitors able to mimic M/PAMPs and activate plant defense may be an alternative for plant protection that could minimize the use of pesticides. Based on this, previous work was conducted by screening a chemical library of 1600 compounds and has allowed the identification of five compounds able to activate defense responses in Arabidopsis thaliana. During my PhD thesis, we tested those five compounds on their abilities to improve resistance of two commercially available flax varieties used for their fibers against F. Oxysporum, responsible of the vascular wilt. The data show that two of them, holaphyllamine (HPA) a natural compound and M4 a synthetic one, did not affect flax growth up to 10 μM. In addition, they did not have any negative effects on F. Oxysporum development and spores germination at the tested concentrations (up to 10 μM). Cell imaging analyses showed that HPA and M4 at 1 μM can induce oxidative burst as well as callose deposition in flax, a well-known marker of PAMP-elicited defense mechanisms. Furthermore, transcriptomic analyses showed that HPA and M4 induced changes in the expression patterns of two pathogenesisrelated (PR) genes (PR-2 and PR-3) coding for a β-(1,3)-glucanase and an endo-chitinase, respectively. These enzymes can degrade the fungal cell wall and stop its growth. Finally, flax plants pre-treated with HPA and M4 before infection with Fo f. Sp. Lini exhibited a decrease in the foliar disease symptoms by more than 50 % and 70 %, respectively. Together, these findings demonstrate that HPA and M4 are elicitors as they are able to activate defense responses in flax plants that lead to improving its resistance against Fo infection
Chuberre, Coralie. "Les microalgues : nouvelles sources de molécules élicitrices pour la santé et la defense des plantes." Thesis, Normandie, 2019. http://www.theses.fr/2019NORMR079.
Повний текст джерелаIntegrated plant protection, which aims to reduce the use of pesticide, is a major challenge for the agriculture of the 21st century. The development and application of new agronomic approaches is a prerequisite for crop protection in a sustainable agriculture system. In this context, the use of elicitors capable of mimicking a pathogenic attack and promoting a plant resistance state against diseases is a natural alternative to the use of agro-chemicals. These elicitors are also called plant defense stimulators (PDS). These can be obtained from different sources including macroalgae as it the case for the polysaccharide-based PDS laminarin that is currently used for the protection of a number of crops. However, the exploitation of these natural resources and the difficulties of their production due to their development cycle do hamper their use at a large scale. One of the possibilities to overcome these difficulties is the use of microalgae as a source of PDS. But this possibility and the potential of microalgaederived PDS for crop protection are currently under investigated. In the present work, we have used a cell extract from the microalgae Phaeodactylum tricornutum and assessed its defense response-eliciting activities on Arabidopsis thaliana seedlings by using microscopic, physiological and molecular approaches. The results show that treated plants exhibit higher levels of expression of the PR-1, PAD3, ACS6 and WRKY40 genes and a higher level of protection against the pathogenic bacterium Pseudomonas syringae DC3000 (Pst) than nontreated plants. An In vitro antibacterial activity on the Pst bacteria was also observed. Our findings suggest that P. tricornutum cell extracts are able to activate plant immune responses and offer new perspectives for the development of novel plant defense stimulators
Jemmali, Lamia. "Stimulateurs des défenses naturelles du blé dur en Tunisie et du blé tendre en France contre la septoriose causée par Zymoseptoria tritici." Thesis, Littoral, 2015. http://www.theses.fr/2015DUNK0455/document.
Повний текст джерелаThe durum wheat (Triticum durum Desf, DW) as well as the bread wheat (Triticum aestivum L. em Thell, BW) is strongly affected by septoria leaf blotch (STB) caused by the hemibiotrophic fungus Zymoseptoria tritici. First, the present work was used to study of the compatible interaction wheat-Z-tritici. The study of the compatible interaction among pathosystems BD/St-08-46 Z-tritici strain an BT/TO1193 Z-tritici strain revealed the induction of defense pathways in both studied pathosystems, but with slight differences. Then, the study of the interaction of Z. tritici with a resistant durum wheat cultivar showed the fungus resistance of association is related to the inhibition of the direct penetration, sporulation and the avtivity of the fungal enzymes degrading plant cell walls (endo-β-1,4-xylanase, endo-β-1,3-glucanase and protease). They seem to be strongly related to the severity of Z. tritici in both BW and DW. In addition, this study revealed the involvement of several genes in the resistance of DW against Z. tritici such as PR2 genes (β-1,3-glucanase), Chi 4 precursor (precursor of Class IV chitinase), Pox (peroxidase), Msr (methionine sulfoxide reductase) and Bsil (protease inhibitor). On the other hand, the potential of resistance inducers (RIs) to protect BW and DW against STB disease was evaluated. Three natural extracts based on ascorbic acid (AA), plant cell wall oligosaccharides (Oligos) and brown algae (Ascophyllum nodosum, A. nod.) were tested for the first time on wheat. Their antifungal effect (direct) and the effect of inducing wheat defense mechanisms (indirect) have been well characterized through molecular, biochemical and cytological. We recorded that only AA exhibited a direct effect on spore germination and hyphal growth of Z. tritici associated to the induction of wheat defense mechanisms. However, conferred protection by Oligos and A. nod appears to be exclusively related to their plant defense inducing properties witch promoted the decrease of fungal CWDE activities and sporulation. Moreover, tested SDPs seem to enhance same defense pathways in both wheat species. They could induce the activation of (i) PR proteins, (ii) the antioxidant enzymes (catalase and peroxidase), (iii) the protein PAL and LOX (key enzymes of the phenylpropanoid and octadecanoid pathways, respectively) and (iv) the cytological accumulation of H₂O₂ and polyphenols, were highlighted. Also, they seem to use same pathways involved in durum wheat resistance mecanisms and may even induce a higher response of defense-related genes as PR2, Pox, Msr, ATPase, and Bsil. In general, protection conferred by tested RIs seems to be dependent on their composition, but it remains constant whatever of the wheat species. Similarly, in filed tested RIs conferred as interesting protection against STB associated, in the case of the A. nod and AA, with increased chlorophyll content and improving yield quantity and quality of the susceptible cultivar Karim, while in the resistant cultivar Salim, the application of RIs seems to be useless. In conclusion, protection conferred by tested RIs seems to be dependent on their composition, but it remains constant whatever of the wheat species. The use of RIs may improve the resistance level and yield of susceptible cultivars in order to obtain similar results to the resistant cultivars. Thus, it could replace the use of resistant cultivars especially with the lack of completely resistant cultivars available to farmers in Tunisia
Mejri, Samara. "Efficacités et modes d'action de nouveaux simulateurs de défenses des plantes sur le pathosystème blé-Zymoseptoria tritici." Thesis, Littoral, 2018. http://www.theses.fr/2018DUNK0481/document.
Повний текст джерелаThe use of biofungicides and elicitors of plant defenses are alternative control stategies that can reduce the use of conventional fungicides. However, there are few products registered and applied on wheat and even less against Septoria tritici blotch. As part of this study, we tested and demonstrated the protective efficacity of several molecules on wheat against Zymoseptoria tritici. In fact, 29 biosourced molecules derived from the functionalization of pyroglutamic acid (PGA) contained in the molasses of sugar beet were evaluated with y-aminobutyric acid GABA, for the first time against Z. tritici. GABA and 16 functionalized molecules significantly reduced the percentages of the disease. The absence of direct effects on the fungus tested in vitro confirms that these protections are due exclusively to an elicitation of plant defense mechanisms. For these molecules, the study of the structure activity relationship has highlighted the importance of different chemical groups involved in the observed protections. On the other hand, the conjugation of PGA with salicylic acid (SA) allowed the obtention of 5 new molecules among which 4 were more effective than the parent molecules and this efficiency seems to be also due to an eliciting effect. Finally, saccharin and three cyclic lipopeptides produced by Bacillus subtilis (mycosubtilin, surfactin and fengycin alone or as mixtures) were evaluated for the first time on the pathosystem wheat - Z. tritici and conferred significant protection due to eliciting properties, direct antifungal activities or combined effects. This study has thus made it possible to identify new molecules with different modes of action and which could be considered in alternative control against wheat leaf blotch, however, additional analyses are required
Ors, Marie-Eva. "Importance du cultivar dans la résistance induite par des stimulateurs de défense des plantes vis-à-vis de mycosphaerella graminicola, agent responsable de la septoriose du blé." Thesis, Littoral, 2015. http://www.theses.fr/2015DUNK0416.
Повний текст джерелаThe use of resistance inducers (RI) is a potential alternative to conventional fungicide treatments against plant fungal diseases. In the present study, we revealed that preventive applications of three RI conferred protection efficacies against M. graminicola, with protection levels varying with the wheat cultivar. Alixan, Premio and Altigo cultivars were previously known to exhibit distinct resistance levels to M. graminicola. The observed protections did not result from a direct effect on spore germination, but were related to the induction of wheat defense mechanisms. The induced resistances reduced foliar necrosis, as well as the sporulation level of the fungus. Microscopic observations of the infection process of M. graminicola and cell wall degrading enzymes (CWDE) activities measured in planta showed that the applied RI as well as the considered treated wheat cultivar influences the impact on the infection process and the protection efficacy. We investigated from the time of treatment until 5 days after inoculation plant peroxidase and phenylalanine ammonia lyase activities and the expression of nine genes involved in distinct defense pathways. Our results indicated that defense mechanisms are differently induced according both to the wheat cultivar and the RI. Therefore, the successful use of RI at the field level strongly depends on the RI-cultivar combination
Bellee, Anthony. "Approches multidisciplinaires sur le mode d’action, l’efficacité et l’élaboration de stratégies d’utilisation d’actifs biologiques contre divers bioagresseurs de Vitis vinifera." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0201.
Повний текст джерелаGrapevine is a perennial crop sensitive to many fungal pathogens that require numerous pesticide treatments. However, its uses lead to environmental, human health and fungicide resistance problems. Developing sustainable pest management strategies while keeping a good wine quality is of major importance. In this sense, the use of bio-pesticides products seems to be a promising approach to combine sustainable and intensive agriculture.Two generalist bio-pesticides of great potential have been preliminary identified, forits actions on major fungal diseases of grapevine. The first one is a natural plant extract, with no direct fungicide action but able to systemically stimulate plant defenses. The second one is a microorganism showing strong antagonist fungicide actions, and important ability to stimulate plant defenses. First, the studies conducted in controlled conditions have demonstrated the effectiveness of both products in the suppression of various isolates of Erysiphe necator, Plasmopara viticola, Botrytis cinerea and Botryosphaeriaceae. In parallel,the good efficiencies of these products have been confirmed during vineyard assays. This was especially well demonstrated for the natural extract. As a whole, these studies confirm thepotential of these two products as promising bio-pesticides, of which the strategy of application have been further defined