Добірка наукової літератури з теми "Defense induction"
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Статті в журналах з теми "Defense induction":
1
Nedeljković, Mitar. "The problem of justifying inductive reasoning." Zbornik radova Filozofskog fakulteta u Pristini 51, no. 2 (2021): 387–408. http://dx.doi.org/10.5937/zrffp51-30620.
Анотація:
In this paper, the author considers the classical strategies of defense from Hume's argument against induction, and assesses the extent to which they were found to be successful. Synthetic, linguistic, a priori, pragmatic, and inductive strategies of defending induction are considered, as well as the question of the extent to which the justification of induction is a problem for grounding scientific knowledge. A new argument is introduced for the a priori justification of induction, as well as a critique of the synthetic and inductive defenses of induction by Black and Jacquette.
2
Paulin, J. P., R. Chartier, M. Tharaud, C. Heintz, V. Karniewicz, and M. N. Brisset. "Induction of resistance to fire blight in apple (Erwinia amylovora)." Plant Protection Science 38, SI 1 - 6th Conf EFPP 2002 (January 1, 2002): S126—S127. http://dx.doi.org/10.17221/10335-pps.
Анотація:
Apple genotypes show different levels of resistance to fire blight caused by the bacterium E. amylovora. This resistance is considered to be polygenic, thus relying on a number of defense mechanisms. On the assumption that in susceptible genotypes these defenses may be present but not activated during the infection process, we attempted their induction by various abiotic and biotic elicitors. Two kinds of experiments were performed in the greenhouse and in the orchard: i) evaluation after controlled inoculation of the level of protection conferred to the plant by each elicitor and ii) investigation of various defense responses potentially involved in the protection. Results showed that some elicitors provided a level of overall protection of about 50% in the orchard while higher levels may be obtained on seedlings in the greenhouse. The comparison of some defense responses in protected and unprotected treated plants showed that i) elicitation of defense is not necessarily associated with control of fire blight and that ii) some responses at least may be associated with the observed protection.
3
GOMES DE OLIVEIRA, HAMILTON, ADRIÁN JOSÉ MOLINA-RUGAMA, MARCOS A. M. FADINI, DANIELA REZENDE, ALBERTO SOTO-G., CLÉBER OLIVEIRA, and ANGELO PALLINI. "Induced defense in Eucalyptus trees increases with prolonged herbivory." Revista Colombiana de Entomología 36, no. 1 (June 30, 2010): 1–4. http://dx.doi.org/10.25100/socolen.v36i1.9109.
Анотація:
Mechanisms of defense in plants can be activated by external stimuli such as herbivory. It is well-known that such induced defense occurs after short periods of herbivory, but little is known about long-term induction. In this paper, we studied the effects of induced defenses of Eucalyptus trees on Thyrinteina arnobia (Lepidoptera: Geometridae) over four generations. The effects of induction of eucalypt plants seemed to increase gradually with prolonged periods of herbivory. To our knowledge it is the first demonstration that induced defense changes in a gradual way with long-term herbivory. This suggests that these trees, and possibly many other plants, gradually invest more in induced defense with prolonged herbivore attacks.
4
Sobral, Mar, Luis Sampedro, Isabelle Neylan, David Siemens, and Rodolfo Dirzo. "Phenotypic plasticity in plant defense across life stages: Inducibility, transgenerational induction, and transgenerational priming in wild radish." Proceedings of the National Academy of Sciences 118, no. 33 (August 13, 2021): e2005865118. http://dx.doi.org/10.1073/pnas.2005865118.
Анотація:
As they develop, many plants deploy shifts in antiherbivore defense allocation due to changing costs and benefits of their defensive traits. Plant defenses are known to be primed or directly induced by herbivore damage within generations and across generations by long-lasting epigenetic mechanisms. However, little is known about the differences between life stages of epigenetically inducible defensive traits across generations. To help fill this knowledge gap, we conducted a multigenerational experiment to determine whether defense induction in wild radish plants was reflected in chromatin modifications (DNA methylation); we then examined differences between seedlings and reproductive plants in current and transgenerational plasticity in chemical (glucosinolates) and physical (trichomes) defenses in this species. Herbivory triggered genome methylation both in targeted plants and their offspring. Within one generation, both defenses were highly inducible at the seedling stage, but only chemical defenses were inducible in reproductive plants. Across generations, herbivory experienced by mother plants caused strong direct induction of physical defenses in their progeny, with effects lasting from seedling to reproductive stages. For chemical defenses, however, this transgenerational induction was evident only in adults. Transgenerational priming was observed in physical and chemical defenses, particularly in adult plants. Our results show that transgenerational plasticity in plant defenses in response to herbivore offense differs for physical and chemical defense and changes across plant life stages.
5
Basu, Saumik, Natalia Moroz, Benjamin W. Lee, Kiwamu Tanaka, Liesl Oeller, Chase W. Baerlocher, and David W. Crowder. "Diversity and Traits of Multiple Biotic Stressors Elicit Differential Defense Responses in Legumes." Agriculture 13, no. 11 (November 3, 2023): 2093. http://dx.doi.org/10.3390/agriculture13112093.
Анотація:
In agroecosystems, plants frequently confront multiple biotic stressors, including herbivores and pathogens. The nature of these interactions plays a crucial role in mediating the activation of plant defense mechanisms. However, induction of plant chemical defenses has been more well studied than the induction of physical defenses. Here, we assessed the physical and chemical defense responses of pea (Pisum sativum) plants after exposure to three stressors: a vector herbivore (pea aphid, Acrythosiphon pisum), a non-vector herbivore (pea leaf weevil, Sitona lineatus), and a virus (Pea enation mosaic virus, PEMV). We used various histochemical staining techniques show that viruliferous A. pisum (transmitting PEMV) strongly induced callose deposition (aniline blue staining) and antioxidant-mediated defenses (DAB and NBT staining) in peas, primarily through accumulating reactive oxygen species (ROS). High-throughput phenotyping showed that viruliferous aphids reduced plant photosynthetic efficiency, but plants infected with PEMV had increased cell death (trypan blue staining). However, herbivory by aphids and weevils did not strongly induce defenses in peas, even though weevil feeding significantly reduced pea leaf area. These results show that not all herbivores induce strong defensive responses, and plant responses to vector species depends on their virus infection status. More broadly, our results indicate that variable stressors differentially regulate various plant responses through intricate chemical and physical defense pathways.
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Boch, Jens, Michelle L. Verbsky, Tara L. Robertson, John C. Larkin, and Barbara N. Kunkel. "Analysis of Resistance Gene-Mediated Defense Responses in Arabidopsis thaliana Plants Carrying a Mutation in CPR5." Molecular Plant-Microbe Interactions® 11, no. 12 (December 1998): 1196–206. http://dx.doi.org/10.1094/mpmi.1998.11.12.1196.
Анотація:
In resistant plants, pathogen attack often leads to rapid activation of defense responses that limit multiplication and spread of the pathogen. To investigate the signaling mechanisms underlying this process, we carried out a screen for mutants in the signaling pathway governing resistance in Arabidopsis thaliana to the bacterial pathogen Pseudomonas syringae. This involved screening for suppressor mutations that restored resistance to a susceptible line carrying a mutation in the RPS2 resistance gene. A mutant that conferred resistance by activating defense responses in the absence of pathogens was isolated. This mutant, which carries a mutation at the CPR5 locus and was thus designated cpr5-2, exhibited resistance to P. syringae, spontaneous development of necrotic lesions, elevated PR gene expression in the absence of pathogens, and abnormal trichomes. Resistance gene-mediated defenses, including the hypersensitive response, restriction of pathogen growth, and induction of defense-related gene expression, were functional in cpr5-2 mutant plants. Additionally, in cpr5-2 plants RPS2-mediated induction of PR-1 expression was enhanced, whereas RPM1-mediated induction of ELI3 was not. These findings suggest that CPR5 encodes a negative regulator of the RPS2 signal transduc-tion pathway.
7
Adhipathi, P., S. Nakkeeran, P. Renuka Devi, R. Velazhahan, and T. Raguchander. "PGPR Induced Differencial Expression of Defence Enzymes Regulating Resistance Against Colletotrichum Capsici in Turmeric." JOURNAL OF ADVANCES IN BIOTECHNOLOGY 4, no. 2 (July 30, 2014): 358–71. http://dx.doi.org/10.24297/jbt.v4i2.5002.
Анотація:
Plant growth promoting Bacillus amyloliquefaciens strain BaTNAU5 and Pseudomonas fluorescens strain Pf3TNAU were evaluated in turmeric for induction defence by differential expression of defence enzymes against Colletotrichum capsici. Further the activity and quantitative assay of the defense enzymes peroxidase (POD), polyphenol oxidase (PPO), phenylalanine ammonia lyase (PAL), β‑1,3-glucanase, chitinase, catalase and defense-inducing chemicals (total phenols) significantly increased with soil and foliar application of B. amyloliquefaciens (BaTNAU5) and P. fluorescens (Pf3TNAU). Western blot analysis of protein extracts from B. amyloliquefaciens (BaTNAU5) and P. fluorescens (Pf3TNAU) challenged with C. capsici, a chitinase with an apparent molecular weight of 28 kDa was induced four days after treatment.
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HOBBS, JESSE. "A Limited Defense of the Pessimistic Induction." British Journal for the Philosophy of Science 45, no. 1 (March 1, 1994): 171–91. http://dx.doi.org/10.1093/bjps/45.1.171.
9
Guarnizo, Nathalie, Diego Oliveros, Walter Murillo-Arango, and María Bianney Bermúdez-Cardona. "Oligosaccharides: Defense Inducers, Their Recognition in Plants, Commercial Uses and Perspectives." Molecules 25, no. 24 (December 16, 2020): 5972. http://dx.doi.org/10.3390/molecules25245972.
Анотація:
Plants have innate immune systems or defense mechanisms that respond to the attack of pathogenic microorganisms. Unlike mammals, they lack mobile defense cells, so defense processes depend on autonomous cellular events with a broad repertoire of recognition to detect pathogens, which compensates for the lack of an adaptive immune system. These defense mechanisms remain inactive or latent until they are activated after exposure or contact with inducing agents, or after the application of the inductor; they remain inactive only until they are affected by a pathogen or challenged by an elicitor from the same. Resistance induction represents a focus of interest, as it promotes the activation of plant defense mechanisms, reducing the use of chemical synthesis pesticides, an alternative that has even led to the generation of new commercial products with high efficiency, stability and lower environmental impact, which increase productivity by reducing not only losses but also increasing plant growth. Considering the above, the objective of this review is to address the issue of resistance induction with a focus on the potential of the use of oligosaccharides in agriculture, how they are recognized by plants, how they can be used for commercial products and perspectives.
10
Schulman, Pablo, Thales H. C. Ribeiro, Mohamed Fokar, Antonio Chalfun-Junior, Richard D. Lally, Paul W. Paré, and Flávio H. V. de Medeiros. "A Microbial Fermentation Product Induces Defense-Related Transcriptional Changes and the Accumulation of Phenolic Compounds in Glycine max." Phytopathology® 112, no. 4 (April 2022): 862–71. http://dx.doi.org/10.1094/phyto-06-21-0227-r.
Анотація:
With the progressive loss of fungicide efficacy against Phakopsora pachyrhizi, the causal agent of Asian soybean rust (ASR), alternative methods to protect soybean crops are needed. Resistance induction is a low impact alternative and/or supplement to fungicide applications that fortifies innate plant defenses against pathogens. Here, we show that a microbial fermentation product (MFP) induces plant defenses in soybean, and transcriptional induction is enhanced with the introduction of ASR. MFP-treated plants exhibited 1,011 and 1,877 differentially expressed genes (DEGs) 12 and 60 h after treatment, respectively, compared with water controls. MFP plants exposed to the pathogen 48 h after application and sampled 12 h later (for a total of 60 h) had 2,401 DEGs compared with control. The plant defense genes PR1, PR2, IPER, PAL, and CHS were induced with MFP application, and induction was enhanced with ASR. Enriched pathways associated with pathogen defense included plant–pathogen interactions, MAPK signaling pathways, phenylpropanoid biosynthesis, glutathione metabolism, flavonoid metabolism, and isoflavonoid metabolism. In field conditions, elevated antioxidant peroxidase activities and phenolic accumulation were measured with MFP treatment; however, improved ASR control or enhanced crop yield were not observed. MFP elicitation differences between field and laboratory grown plants necessitates further testing to identify best practices for effective disease management with MFP-treated soybean.
Дисертації з теми "Defense induction":
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/.
Анотація:
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.
Анотація:
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.
Анотація:
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.
Анотація:
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.
Анотація:
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.
Книги з теми "Defense induction":
1
W, Tallamy Douglas, and Raupp Michael J, eds. Phytochemical induction by herbivores. New York: Wiley, 1991.
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Fred, Wilson. Hume's defence of causal inference. Toronto: University of Toronto Press, 1997.
3
David, Miller. Critical rationalism: A restatement and defence. Chicago, USA: Open Court, 1994.
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Lo, Chang-yun. Optimizing ship air-defense evaluation model using simulation and inductive learning. Monterey, Calif: Naval Postgraduate School, 1991.
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Ashfield, Thomas. Induction of defence-related gene promoters during interactions between tomato and cladosporium fulvum. Norwich: University of East Anglia, 1993.
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Using an Inductive Learning Algorithm to Improve Antibody Generation in a Single Packet Computer Defense Immune System. Storming Media, 2002.
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Stegenga, Jacob. Medical Nihilism. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198747048.001.0001.
Анотація:
This book defends medical nihilism, which is the view that we should have little confidence in the effectiveness of medical interventions. If we consider the frequency of failed medical interventions, the extent of misleading evidence in medical research, the thin theoretical basis of many interventions, and the malleability of empirical methods in medicine, and if we employ our best inductive framework, then our confidence in the effectiveness of medical interventions ought to be low. Part I articulates theoretical and conceptual groundwork, which offers a defense of a hybrid theory of disease, which forms the basis of a novel account of effectiveness, and this is applied to pharmacological science and to issues such as medicalization. Part II critically examines details of medical research. Even the very best methods in medical research, such as randomized trials and meta-analyses, are malleable and suffer from various biases. Methods of measuring the effectiveness of medical interventions systematically overestimate benefits and underestimate harms. Part III summarizes the arguments for medical nihilism and what this position entails for medical research and practice. To evaluate medical nihilism with care, the argument is stated in formal terms. Medical nihilism suggests that medical research must be modified, that clinical practice should be less aggressive in its therapeutic approaches, and that regulatory standards should be enhanced.
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Government, U. S., National Intelligence University, Center for Strategic Intelligence Research, Department of Defense, and National Defense Intelligence College. National Defense Intelligence College Paper: Critical Thinking and Intelligence Analysis - Sherman Kent, NSA, JFK, Cuban Missile Crisis, Inductive, Deductive, Abductive Reasoning. Independently Published, 2017.
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Johnsen, Bredo. David Hume. Oxford University Press, 2017. http://dx.doi.org/10.1093/acprof:oso/9780190662776.003.0005.
Анотація:
In this chapter the author presents Hume’s “skeptical” argument for the conclusion that there is no rational link between our observational and memorial/observational knowledge of the world and our theories about it, and defends it at length against the objection that it fails to consider probabilistic connections between evidence and theory. The author also defends Hume’s claim that our most elementary inferences are not made by any process of reasoning, but by habit and custom, against the charge that it fails to solve the problem of the missing rational link. His critics have misunderstood his claim, which is simply to have identified the means by which we arrive at the conclusions of those inferences. The author then presents Hume’s solution to the problem they have in mind, namely how any of our inductive inferences are justified: reflective equilibrium theory.
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Williams, Donald C. The Duty of Philosophy. Edited by A. R. J. Fisher. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198810384.003.0002.
Анотація:
This chapter concerns the nature of metaphysics and a defense of it through a clarification of what role it plays in our theorizing of the world. It is argued that metaphysics and science are on the same continuum and that therefore the same empirical methods apply to metaphysics and the sciences. The ontology/cosmology distinction and the analytic/speculative distinction are introduced and explained. Ontology is the study of being as such and is concerned with general features of every existent, whereas cosmology is the study of how every existent is related to every other in general terms. Analytic inquiry concerns the nature of something and is therefore deductive, whereas speculative inquiry concerns why certain things come into being and is therefore inductive. Both distinctions are distinct. The resulting proposal is that metaphysics has two branches: ontology and cosmology, and either branch can be investigated analytically or speculatively.
Частини книг з теми "Defense induction":
1
Walters, Dale R., and Alison E. Bennett. "Microbial Induction of Resistance to Pathogens." In Induced Resistance for Plant Defense, 149–70. Chichester, UK: John Wiley & Sons, Ltd, 2014. http://dx.doi.org/10.1002/9781118371848.ch8.
2
Chen, Chang-Hwei. "Induction of Metabolic Enzymes for Health Effects." In Xenobiotic Metabolic Enzymes: Bioactivation and Antioxidant Defense, 193–203. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-41679-9_17.
3
Hickey, Michael A., and Diane Wallace Taylor. "The Inducible Defense System: The Induction and Development of the Inducible Defence." In Infection, Resistance, and Immunity, 131–56. Boca Raton: Routledge, 2022. http://dx.doi.org/10.1201/9780203750964-8.
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Hamel, Louis-Philippe, and Nathalie Beaudoin. "Induction of Plant Defense Response and Its Impact on Productivity." In Bacteria in Agrobiology: Crop Productivity, 309–27. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-37241-4_13.
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Klessig, Daniel F., Jocelyn Malamy, Jacek Hennig, Zhixiang Chen, Paloma Sanchez-Casas, Janusz Indulski, and Grzegorz Grynkiewicz. "Induction, Modification, and Reception of the Salicylic Acid Signal in Plant Defense." In Developments in Plant Pathology, 185–95. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-1737-1_60.
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Bastian, Neil R., Chang-Yeol Yim, John B. Hibbs, and Wolfram E. Samlowski. "Induction of Iron-Nitric Oxide EPR Signals in Murine Cancers: Effects of Thiols and Cytokine-Induced Oxidant Stress." In Nitric Oxide in Transplant Rejection and Anti-Tumor Defense, 295–311. Boston, MA: Springer US, 1998. http://dx.doi.org/10.1007/978-1-4615-5081-5_19.
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Stäb, Margarita R., and Jürgen Ebel. "Role of Ca2+ in the Induction of the Phytoalexin Defense Response in Soybean Cells." In Molecular and Cellular Aspects of Calcium in Plant Development, 331–32. Boston, MA: Springer US, 1986. http://dx.doi.org/10.1007/978-1-4613-2177-4_46.
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Patel, Stuti, Riyaz Z. Sayyed, and Meenu Saraf. "Bacterial Determinants and Plant Defense Induction: Their Role as Biocontrol Agents in Sustainable Agriculture." In Plant, Soil and Microbes, 187–204. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-29573-2_9.
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Heil, Martin. "Airborne Induction and Priming of Defenses." In Plant-Environment Interactions, 137–52. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-540-89230-4_8.
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Alba, Juan M., Silke Allmann, Joris J. Glas, Bernardus C. J. Schimmel, Eleni A. Spyropoulou, Marije Stoops, Carlos Villarroel, and Merijn R. Kant. "Induction and Suppression of Herbivore-Induced Indirect Defenses." In Biocommunication of Plants, 197–212. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-23524-5_11.
Тези доповідей конференцій з теми "Defense induction":
1
Miller, Jonathan S., Chet Bassani, and Gregory Schultz. "Extended-range electromagnetic induction concepts." In SPIE Defense + Security, edited by Steven S. Bishop and Jason C. Isaacs. SPIE, 2015. http://dx.doi.org/10.1117/12.2177476.
2
Won, I. J., and Dean A. Keiswetter. "Electromagnetic induction spectroscopy." In Aerospace/Defense Sensing and Controls, edited by Abinash C. Dubey, James F. Harvey, and J. Thomas Broach. SPIE, 1998. http://dx.doi.org/10.1117/12.324186.
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Reed, Mark A., and Waymond R. Scott. "Implementation of optimized electromagnetic induction coils." In SPIE Defense + Security, edited by Steven S. Bishop and Jason C. Isaacs. SPIE, 2014. http://dx.doi.org/10.1117/12.2050464.
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Scott, Waymond R. "Improved feedback amplifier for electromagnetic induction sensors." In SPIE Defense + Security, edited by Steven S. Bishop and Jason C. Isaacs. SPIE, 2016. http://dx.doi.org/10.1117/12.2224199.
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Scott, Jr., Waymond R., and Michael Malluck. "New cancellation technique for electromagnetic induction sensors." In Defense and Security, edited by Russell S. Harmon, J. Thomas Broach, and John H. Holloway, Jr. SPIE, 2005. http://dx.doi.org/10.1117/12.603854.
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Gautama, Sidharta, and Johannes P. D'Haeyer. "Automatic induction of relational models." In Aerospace/Defense Sensing and Controls, edited by David P. Casasent and Andrew G. Tescher. SPIE, 1996. http://dx.doi.org/10.1117/12.242013.
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Zhang, Kun, Zujia Xu, and Bill P. Buckles. "Oblique decision tree induction using multimembered evolution strategies." In Defense and Security, edited by Belur V. Dasarathy. SPIE, 2005. http://dx.doi.org/10.1117/12.596766.
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Miller, Jonathan S., Joe Keranen, and Gregory Schultz. "Optimizing electromagnetic induction sensors for dynamic munitions classification surveys." In SPIE Defense + Security, edited by Steven S. Bishop and Jason C. Isaacs. SPIE, 2014. http://dx.doi.org/10.1117/12.2050762.
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Rasouli, Mohammad. "Term selection for an induction motor via nonlinear Lasso." In SPIE Defense + Security, edited by Edward M. Carapezza. SPIE, 2014. http://dx.doi.org/10.1117/12.2052792.
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Kerr, Andrew J., Waymond R. Scott, Charles Ethan Hayes, and James H. McClellan. "Target location estimation for single channel electromagnetic induction data." In SPIE Defense + Security, edited by Steven S. Bishop and Jason C. Isaacs. SPIE, 2017. http://dx.doi.org/10.1117/12.2262892.
Звіти організацій з теми "Defense induction":
1
Avni, Adi, and Kirankumar S. Mysore. Functional Genomics Approach to Identify Signaling Components Involved in Defense Responses Induced by the Ethylene Inducing Xyalanase Elicitor. United States Department of Agriculture, December 2009. http://dx.doi.org/10.32747/2009.7697100.bard.
Анотація:
Plant-microbe interactions involve a large number of global regulatory systems, which are essential for plants to protect themselves against pathogen attack. An ethylene-inducing xylanase (EIX) of Trichoderma viride is a potent elicitor of plant defense responses, like hypersensitive response (HR), in specific cultivars of tobacco (Nicotiana tabacum) and tomato (Lycopersicon esculentum). The central goal of this proposal was to investigate the molecular mechanisms that allow plants to specifically activate defense responses after EIX treatment. We proposed to identify cellular signaling components involved in the induction of HR by the EIX elicitor. The molecular genetic analysis of the signal transduction pathway that modulates hypersensitive responses is an important step in understanding the induction of plant defense responses. The genes that mediate LeEIX2-EIX dependent activation of resistance mechanisms remain to be identified. We used two approaches to identify the cellular signaling components that induce HR mediated by the EIX elicitor. In the first approach, we performed a yeast two-hybrid screening using LeEix2 as bait to identify plant proteins that interact with it. In the second approach, we used virus-induced gene silencing (VIGS) for a high-throughput screen to identify genes that are required for the induction of LeEIX2-EIX mediated HR. VIGS will also be used for functional characterization of genes that will be identified during the yeast two-hybrid screen. This investigation will shed light on cellular processes and signaling components involved in induction of general plant defense against pathogens and will provide the basis for future biotechnological approaches to improve plant resistance to pathogens. Several genes were indentified by the two approaches. We used the VIGS and yeast two hybrid approaches to confirm that activity of the genes initially identified by different procedure. Two genes inhibit the induction of HR by the fungal elicitor in the different systems; Tobacco-Harpin binding protein 1 and cyclopropyl isomerase.
2
Smith, Gary, Dong-Sang Kim, Michael Schweiger, James Marra, Jesse Lang, Jarrod Crum, Charles Crawford, and John Vienna. Silicate Based Glass Formulations for Immobilization of U.S. Defense Wastes Using Cold Crucible Induction Melters. Office of Scientific and Technical Information (OSTI), May 2014. http://dx.doi.org/10.2172/1136616.
3
Gal-On, Amit, Shou-Wei Ding, Victor P. Gaba, and Harry S. Paris. role of RNA-dependent RNA polymerase 1 in plant virus defense. United States Department of Agriculture, January 2012. http://dx.doi.org/10.32747/2012.7597919.bard.
Анотація:
Objectives: Our BARD proposal on the impact of RNA-dependent RNA polymerase 1 (RDR1) in plant defense against viruses was divided into four original objectives. 1. To examine whether a high level of dsRNA expression can stimulate RDR1 transcription independent of salicylic acid (SA) concentration. 2. To determine whether the high or low level of RDR1 transcript accumulation observed in virus resistant and susceptible cultivars is associated with viral resistance and susceptibility. 3. To define the biogenesis and function of RDR1-dependent endogenous siRNAs. 4. To understand why Cucumber mosaic virus (CMV) can overcome RDR1-dependent resistance. The objectives were slightly changed due to the unique finding that cucumber has four different RDR1 genes. Background to the topic: RDR1 is a key plant defense against viruses. RDR1 is induced by virus infection and produces viral and plant dsRNAs which are processed by DICERs to siRNAs. siRNAs guide specific viral and plant RNA cleavage or serve as primers for secondary amplification of viral-dsRNA by RDR. The proposal is based on our preliminary results that a. the association of siRNA and RDR1 accumulation with multiple virus resistance, and b. that virus infection induced the RDR1-dependent production of a new class of endogenous siRNAs. However, the precise mechanisms underlying RDR1 induction and siRNA biogenesis due to virus infection remain to be discovered in plants. Major conclusions, solutions and achievements: We found that in the cucurbit family (cucumber, melon, squash, watermelon) there are 3-4 RDR1 genes not documented in other plant families. This important finding required a change in the emphasis of our objectives. We characterized 4 RDR1s in cucumber and 3 in melon. We demonstrated that in cucumber RDR1b is apparently a new broad spectrum virus resistance gene, independent of SA. In melon RDR1b is truncated, and therefore is assumed to be the reason that melon is highly susceptible to many viruses. RDR1c is dramatically induced due to DNA and RNA virus infection, and inhibition of RDR1c expression led to increased virus accumulation which suggested its important on gene silencing/defense mechanism. We show that induction of antiviral RNAi in Arabidopsis is associated with production of a genetically distinct class of virus-activated siRNAs (vasiRNAs) by RNA dependent RNA polymerase-1 targeting hundreds of host genes for RNA silencing by Argonaute-2. Production of vasiRNAs is induced by viruses from two different super groups of RNA virus families, targeted for inhibition by CMV, and correlated with virus resistance independently of viral siRNAs. We propose that antiviral RNAi activate broad-spectrum antiviral activity via widespread silencing of host genes directed by vasiRNAs, in addition to specific antiviral defense Implications both scientific and agricultural: The RDR1b (resistance) gene can now be used as a transcription marker for broad virus resistance. The discovery of vasiRNAs expands the repertoire of siRNAs and suggests that the siRNA-processing activity of Dicer proteins may play a more important role in the regulation of plant and animal gene expression than is currently known. We assume that precise screening of the vasiRNA host targets will lead in the near future for identification of plant genes associate with virus diseases and perhaps other pathogens.
4
Jander, Georg, and Daniel Chamovitz. Investigation of growth regulation by maize benzoxazinoid breakdown products. United States Department of Agriculture, January 2015. http://dx.doi.org/10.32747/2015.7600031.bard.
Анотація:
Introduction Previous research had suggested that benzoxazinoids, a class of defensive metabolites found in maize, wheat, rye, and wild barley, are not only direct insect deterrents, but also influence other areas of plant metabolism. In particular, the benzoxazinoid 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxa- zin-3(4H)- one (DIMBOA) was implicated in: (i) altering plant growth by interfering with auxin signaling, and (ii) leading to the induction of gene expression changes and secondary plant defense responses. The overall goal of this proposal was to identify mechanisms by which benzoxazinoids influence other aspects of plant growth and defense. Specifically, the following hypotheses were proposed to be tested as part of an approved BARD proposal: Benzoxazinoid breakdown products directly interfere with auxin perception Global changes in maize and barley gene expression are induced by benzoxazinoid activation. There is natural variation in the maize photomorphogenic response to benzoxazinoids. Although the initial proposal included experiments with both maize and barley, there were some technical difficulties with the proposed transgenic barley experiments and most of the experimental results were generated with maize. Summary of major findings Previous research by other labs, involving both maize and other plant species, had suggested that DIMBOA alters plant growth by interfering with auxin signaling. However, experiments conducted in both the Chamovitz and the Jander labs using Arabidopsis and maize, respectively, were unable to confirm previously published reports of exogenously added DIMBOA effects on auxin signaling. Nevertheless, analysis of bx1 and bx2 maize mutant lines, which have almost no detectable benzoxazinoids, showed altered responses to blue light signaling. Transcriptomic analysis of maize mutant lines, variation in inbred lines, and responses to exogenously added DIMBOA showed alteration in the transcription of a blue light receptor, which is required for plant growth responses. This finding provides a novel mechanistic explanation of the trade-off between growth and defense that is often observed in plants. Experiments by the Jander lab and others had demonstrated that DIMBOA not only has direct toxicity against insect pests and microbial pathogens, but also induces the formation of callose in both maize and wheat. In the current project, non-targeted metabolomic assays of wildtype maize and mutants with defects in benzoxazinoid biosynthesis were used to identify unrelated metabolites that are regulated in a benzoxazinoid-dependent manner. Further investigation identified a subset of these DIMBOA-responsive compounds as catechol, as well as its glycosylated and acetylated derivatives. Analysis of co-expression data identified indole-3-glycerol phosphate synthase (IGPS) as a possible regulator of benzoxazinoid biosynthesis in maize. In the current project, enzymatic activity of three predicted maize IGPS genes was confirmed by heterologous expression. Transposon knockout mutations confirmed the function of the maize genes in benzoxazinoid biosynthesis. Sub-cellular localization studies showed that the three maize IGPS proteins are co-localized in the plastids, together with BX1 and BX2, two previously known enzymes of the benzoxazinoid biosynthesis pathway. Implications Benzoxazinoids are among the most abundant and effective defensive metabolites in maize, wheat, and rye. Although there is considerable with-in species variation in benzoxazinoid content, very little is known about the regulation of this variation and the specific effects on plant growth and defense. The results of this research provide further insight into the complex functions of maize benzoxazinoids, which are not only toxic to pests and pathogens, but also regulate plant growth and other defense responses. Knowledge gained through the current project will make it possible to engineer benzoxazinoid biosynthesis in a more targeted manner to produce pest-tolerant crops without negative effects on growth and yield.
5
Avni, Adi, and Gitta L. Coaker. Proteomic investigation of a tomato receptor like protein recognizing fungal pathogens. United States Department of Agriculture, January 2015. http://dx.doi.org/10.32747/2015.7600030.bard.
Анотація:
Maximizing food production with minimal negative effects on the environment remains a long-term challenge for sustainable food production. Microbial pathogens cause devastating diseases, minimizing crop losses by controlling plant diseases can contribute significantly to this goal. All plants possess an innate immune system that is activated after recognition of microbial-derived molecules. The fungal protein Eix induces defense responses in tomato and tobacco. Plants recognize Eix through a leucine-rich-repeat receptor- like-protein (LRR-RLP) termed LeEix. Despite the knowledge obtained from studies on tomato, relatively little is known about signaling initiated by RLP-type immune receptors. The focus of this grant proposal is to generate a foundational understanding of how the tomato xylanase receptor LeEix2 signals to confer defense responses. LeEix2 recognition results in pattern triggered immunity (PTI). The grant has two main aims: (1) Isolate the LeEix2 protein complex in an active and resting state; (2) Examine the biological function of the identified proteins in relation to LeEix2 signaling upon perception of the xylanase elicitor Eix. We used two separate approaches to isolate receptor interacting proteins. Transgenic tomato plants expressing LeEix2 fused to the GFP tag were used to identify complex components at a resting and activated state. LeEix2 complexes were purified by mass spectrometry and associated proteins identified by mass spectrometry. We identified novel proteins that interact with LeEix receptor by proteomics analysis. We identified two dynamin related proteins (DRPs), a coiled coil – nucleotide binding site leucine rich repeat (SlNRC4a) protein. In the second approach we used the split ubiquitin yeast two hybrid (Y2H) screen system to identified receptor-like protein kinase At5g24010-like (SlRLK-like) (Solyc01g094920.2.1) as an interactor of LeEIX2. We examined the role of SlNRC4a in plant immunity. Co-immunoprecipitation demonstrates that SlNRC4a is able to associate with different PRRs. Physiological assays with specific elicitors revealed that SlNRC4a generally alters PRR-mediated responses. SlNRC4a overexpression enhances defense responses while silencing SlNRC4 reduces plant immunity. We propose that SlNRC4a acts as a non-canonical positive regulator of immunity mediated by diverse PRRs. Thus, SlNRC4a could link both intracellular and extracellular immune perception. SlDRP2A localizes at the plasma membrane. Overexpression of SlDRP2A increases the sub-population of LeEIX2 inVHAa1 endosomes, and enhances LeEIX2- and FLS2-mediated defense. The effect of SlDRP2A on induction of plant immunity highlights the importance of endomembrane components and endocytosis in signal propagation during plant immune . The interaction of LeEIX2 with SlRLK-like was verified using co- immunoprecipitation and a bimolecular fluorescence complementation assay. The defence responses induced by EIX were markedly reduced when SlRLK-like was over-expressed, and mutation of slrlk-likeusing CRISPR/Cas9 increased EIX- induced ethylene production and SlACSgene expression in tomato. Co-expression of SlRLK-like with different RLPs and RLKs led to their degradation, apparently through an endoplasmic reticulum-associated degradation process. We provided new knowledge and expertise relevant to expression of specific be exploited to enhance immunity in crops enabling the development of novel environmentally friendly disease control strategies.
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Manulis, Shulamit, Christine D. Smart, Isaac Barash, Guido Sessa, and Harvey C. Hoch. Molecular Interactions of Clavibacter michiganensis subsp. michiganensis with Tomato. United States Department of Agriculture, January 2011. http://dx.doi.org/10.32747/2011.7697113.bard.
Анотація:
Clavibacter michiganensis subsp. michiganensis (Cmm), the causal agent of bacterial wilt and canker of tomato, is the most destructive bacterial disease of tomato causing substantial economic losses in Israel, the U.S.A. and worldwide. The molecular strategies that allow Cmm, a Gram-positive bacterium, to develop a successful infection in tomato plants are largely unknown. The goal of the project was to elucidate the molecular interactions between Cmmand tomato. The first objective was to analyze gene expression profiles of susceptible tomato plants infected with pathogenic and endophytic Cmmstrains. Microarray analysis identified 122 genes that were differentially expressed during early stages of infection. Cmm activated typical basal defense responses in the host including induction of defense-related genes, production of scavenging of free oxygen radicals, enhanced protein turnover and hormone synthesis. Proteomic investigation of the Cmm-tomato interaction was performed with Multi-Dimensional Protein Identification Technology (MudPIT) and mass spectroscopy. A wide range of enzymes secreted by Cmm382, including cell-wall degrading enzymes and a large group of serine proteases from different families were identified in the xylem sap of infected tomato. Based on proteomic results, the expression pattern of selected bacterial virulence genes and plant defense genes were examined by qRT-PCR. Expression of the plasmid-borne cellulase (celA), serine protease (pat-1) and serine proteases residing on the chp/tomA pathogenicity island (chpCandppaA), were significantly induced within 96 hr after inoculation. Transcription of chromosomal genes involved in cell wall degradation (i.e., pelA1, celB, xysA and xysB) was also induced in early infection stages. The second objective was to identify by VIGS technology host genes affecting Cmm multiplication and appearance of disease symptoms in plant. VIGS screening showed that out of 160 tomato genes, which could be involved in defense-related signaling, suppression of 14 genes led to increase host susceptibility. Noteworthy are the genes Snakin-2 (inhibitor of Cmm growth) and extensin-like protein (ELP) involved in cell wall fortification. To further test the significance of Snakin -2 and ELP in resistance towards Cmm, transgenic tomato plants over-expressing the two genes were generated. These plants showed partial resistance to Cmm resulting in a significant delay of the wilt symptoms and reduction in size of canker lesion compared to control. Furthermore, colonization of the transgenic plants was significantly lower. The third objective was to assess the involvement of ethylene (ET), jasmonate (JA) and salicylic acid (SA) in Cmm infection. Microarray and proteomic studies showed the induction of enzymes involved in ET and JA biosynthesis. Cmm promoted ET production 8 days after inoculation and SIACO, a key enzyme of ET biosynthesis, was upregulated. Inoculation of the tomato mutants Never ripe (Nr) impaired in ET perception and transgenic plants with reduced ET synthesis significantly delayed wilt symptoms as compared to the wild-type plants. The retarded wilting in Nr plants was shown to be a specific effect of ET insensitivity and was not due to altered expression of defense related genes, reduced bacterial population or decrease in ethylene biosynthesis . In contrast, infection of various tomato mutants impaired in JA biosynthesis (e.g., def1, acx1) and JA insensitive mutant (jai1) yielded unequivocal results. The fourth objective was to determine the role of cell wall degrading enzymes produced by Cmm in xylem colonization and symptoms development. A significance increase (2 to 7 fold) in expression of cellulases (CelA, CelB), pectate lyases (PelA1, PelA2), polygalacturonase and xylanases (XylA, XylB) was detected by qRT-PCR and by proteomic analysis of the xylem sap. However, with the exception of CelA, whose inactivation led to reduced wilt symptoms, inactivation of any of the other cell wall degrading enzymes did not lead to reduced virulence. Results achieved emphasized the complexity involved in Cmm-tomato interactions. Nevertheless they provide the basis for additional research which will unravel the mechanism of Cmm pathogenicity and formulating disease control measures.
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Manulis-Sasson, Shulamit, Christine D. Smart, Isaac Barash, Laura Chalupowicz, Guido Sessa, and Thomas J. Burr. Clavibacter michiganensis subsp. michiganensis-tomato interactions: expression and function of virulence factors, plant defense responses and pathogen movement. United States Department of Agriculture, February 2015. http://dx.doi.org/10.32747/2015.7594405.bard.
Анотація:
Clavibactermichiganensissubsp. michiganensis(Cmm), the causal agent of bacterial wilt and canker of tomato, is the most destructive bacterial disease of tomato causing substantial economic losses in Israel, the U.S.A. and worldwide. The goal of the project was to unravel the molecular strategies that allow Cmm, a Gram-positive bacterium, to develop a successful infection in tomato. The genome of Cmm contains numerous genes encoding for extracellular serine proteases and cell wall degrading enzymes. The first objective was to elucidate the role of secreted serine proteases in Cmm virulence. Mutants of nine genes encoding serine proteases of 3 different families were tested for their ability to induce wilting, when tomato stems were puncture-inoculated, as compared to blisters formation on leaves, when plants were spray-inoculated. All the mutants showed reduction in wilting and blister formation as compared to the wild type. The chpCmutant displayed the highest reduction, implicating its major role in symptom development. Five mutants of cell wall degrading enzymes and additional genes (i.e. perforin and sortase) caused wilting but were impaired in their ability to form blisters on leaves. These results suggest that Cmm differentially expressed virulence genes according to the site of penetration. Furthermore, we isolated and characterized two Cmmtranscriptional activators, Vatr1 and Vatr2 that regulate the expression of virulence factors, membrane and secreted proteins. The second objective was to determine the effect of bacterial virulence genes on movement of Cmm in tomato plants and identify the routes by which the pathogen contaminates seeds. Using a GFP-labeledCmm we could demonstrate that Cmm extensively colonizes the lumen of xylem vessels and preferentially attaches to spiral secondary wall thickening of the protoxylem and formed biofilm-like structures composed of large bacterial aggregates. Our findings suggest that virulence factors located on the chp/tomAPAI or the plasmids are required for effective movement of the pathogen in tomato and for the formation of cellular aggregates. We constructed a transposon plasmid that can be stably integrated into Cmm chromosome and express GFP, in order to follow movement to the seeds. Field strains from New York that were stably transformed with this construct, could not only access seeds systemically through the xylem, but also externally through tomato fruit lesions, which harbored high intra-and intercellular populations. Active movement and expansion of bacteria into the fruit mesocarp and nearby xylem vessels followed, once the fruit began to ripen. These results highlight the ability of Cmm to invade tomato fruit and seed through multiple entry routes. The third objective was to assess correlation between disease severity and expression levels of Cmm virulence genes and tomato defense genes. The effect of plant age on expression of tomato defense related proteins during Cmm infection was analyzed by qRT-PCR. Five genes out of eleven showed high induction at early stages of infection of plants with 19/20 leaves compared to young plants bearing 7/8 leaves. Previous results showed that Cmm virulence genes were expressed at early stages of infection in young plants compared to older plants. Results of this study suggest that Cmm virulence genes may suppress expression of tomato defense-related genes in young plants allowing effective disease development. The possibility that chpCis involved in suppression of tomato defense genes is currently under investigation by measuring the transcript level of several PR proteins, detected previously in our proteomics study. The fourth objective was to define genome location and stability of virulence genes in Cmm strains. New York isolates were compared to Israeli, Serbian, and NCPPB382 strains. The plasmid profiles of New York isolates were diverse and differed from both Israeli and Serbian strains. PCR analysis indicated that the presence of putative pathogenicity genes varied between isolates and highlighted the ephemeral nature of pathogenicity genes in field populations of Cmm. Results of this project significantly contributed to the understanding of Cmm virulence, its movement within tomato xylem or externally into the seeds, the role of serine proteases in disease development and initiated research on global regulation of Cmm virulence. These results form a basis for developing new strategies to combat wilt and canker disease of tomato.
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Sessa, Guido, and Gregory Martin. A functional genomics approach to dissect resistance of tomato to bacterial spot disease. United States Department of Agriculture, January 2004. http://dx.doi.org/10.32747/2004.7695876.bard.
Анотація:
The research problem. Bacterial spot disease in tomato is of great economic importance worldwide and it is particularly severe in warm and moist areas affecting yield and quality of tomato fruits. Causal agent of spot disease is the Gram-negative bacterium Xanthomonas campestris pv. vesicatoria (Xcv), which can be a contaminant on tomato seeds, or survive in plant debris and in association with certain weeds. Despite the economic significance of spot disease, plant protection against Xcvby cultural practices and chemical control have so far proven unsuccessful. In addition, breeding for resistance to bacterial spot in tomato has been undermined by the genetic complexity of the available sources of resistance and by the multiple races of the pathogen. Genetic resistance to specific Xcvraces have been identified in tomato lines that develop a hypersensitive response and additional defense responses upon bacterial challenge. Central goals of this research were: 1. To identify plant genes involved in signaling and defense responses that result in the onset of resistance. 2. To characterize molecular properties and mode of action of bacterial proteins, which function as avirulence or virulence factors during the interaction between Xcvand resistant or susceptible tomato plants, respectively. Our main achievements during this research program are in three major areas: 1. Identification of differentially expressed genes during the resistance response of tomato to Xcvrace T3. A combination of suppression subtractive hybridization and microarray analysis identified a large set of tomato genes that are induced or repressed during the response of resistant plants to avirulent XcvT3 bacteria. These genes were grouped in clusters based on coordinate expression kinetics, and classified into over 20 functional classes. Among them we identified genes that are directly modulated by expression of the type III effector protein AvrXv3 and genes that are induced also during the tomato resistance response to Pseudomonas syringae pv. tomato. 2. Characterization of molecular and biochemical properties of the tomato LeMPK3MAP kinase. A detailed molecular and biochemical analysis was performed for LeMPK3 MAP kinase, which was among the genes induced by XcvT3 in resistant tomato plants. LeMPK3 was induced at the mRNA level by different pathogens, elicitors, and wounding, but not by defense-related plant hormones. Moreover, an induction of LeMPK3 kinase activity was observed in resistant tomato plants upon Xcvinfection. LeMPK3 was biochemically defined as a dual-specificity MAP kinase, and extensively characterized in vitro in terms of kinase activity, sites and mechanism of autophosphorylation, divalent cation preference, Kₘand Vₘₐₓ values for ATP. 3. Characteriztion of molecular properties of the Xcveffector protein AvrRxv. The avirulence gene avrRxvis involved in the genetic interaction that determines tomato resistance to Xcvrace T1. We found that AvrRxv functions inside the plant cell, localizes to the cytoplasm, and is sufficient to confer avirulence to virulent Xcvstrains. In addition, we showed that the AvrRxv cysteine protease catalytic core is essential for host recognition. Finally, insights into cellular processes activated by AvrRxv expression in resistant plants were obtained by microarray analysis of 8,600 tomato genes. Scientific and agricultural significance: The findings of these activities depict a comprehensive and detailed picture of cellular processes taking place during the onset of tomato resistance to Xcv. In this research, a large pool of genes, which may be involved in the control and execution of plant defense responses, was identified and the stage is set for the dissection of signaling pathways specifically triggered by Xcv.
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Sessa, Guido, and Gregory B. Martin. molecular link from PAMP perception to a MAPK cascade associated with tomato disease resistance. United States Department of Agriculture, January 2012. http://dx.doi.org/10.32747/2012.7597918.bard.
Анотація:
The research problem: The detection of pathogen-associated molecular patterns (PAMPs) by plant pattern recognition receptors (PRRs) is a key mechanism by which plants activate an effective immune response against pathogen attack. MAPK cascades are important signaling components downstream of PRRs that transduce the PAMP signal to activate various defense responses. Preliminary experiments suggested that the receptor-like cytoplasmickinase (RLCK) Mai5 plays a positive role in pattern-triggered immunity (PTI) and interacts with the MAPKKK M3Kε. We thus hypothesized that Mai5, as other RLCKs, functions as a component PRR complexes and acts as a molecular link between PAMP perception and activation of MAPK cascades. Original goals: The central goal of this research was to investigate the molecular mechanisms by which Mai5 and M3Kε regulate plant immunity. Specific objectives were to: 1. Determine the spectrum of PAMPs whose perception is transmitted by M3Kε; 2. Identify plant proteins that act downstream of M3Kε to mediate PTI; 3. Investigate how and where Mai5 interacts with M3Kε in the plant cell; 4. Examine the mechanism by which Mai5 contributes to PTI. Changes in research directions: We did not find convincing evidence for the involvement of M3Kε in PTI signaling and substituted objectives 1 and 3 with research activities aimed at the analysis of transcriptomic profiles of tomato plants during the onset of plant immunity, isolation of the novel tomato PRR FLS3, and investigation of the involvement of the RLCKBSKs in PTI. Main achievements during this research program are in the following major areas: 1. Functional characterization of Mai5. The function of Mai5 in PTI signaling was demonstrated by testing the effect of silencing the Mai5 gene by virus-induced gene silencing (VIGS) experiments and in cell death assays. Domains of Mai5 that interact with MAPKKKs and subcellular localization of Mai5 were analyzed in detail. 2. Analysis of transcriptional profiles during the tomato immune responses to Pseudomonas syringae (Pombo et al., 2014). We identified tomato genes whose expression is induced specifically in PTI or in effector-triggered immunity (ETI). Thirty ETI-specific genes were examined by VIGS for their involvement in immunity and the MAPKKK EPK1, was found to be required for ETI. 3. Dissection of MAP kinase cascades downstream of M3Kε (Oh et al., 2013; Teper et al., 2015). We identified genes that encode positive (SGT and EDS1) and negative (WRKY1 and WRKY2) regulators of the ETI-associated cell death mediated by M3Kε. In addition, the MKK2 MAPKK, which acts downstream of M3Kε, was found to interact with the MPK3 MAPK and specific MPK3 amino acids involved interaction were identified and found to be required for induction of cell death. We also identified 5 type III effectors of the bacterial pathogen Xanthomonaseuvesicatoria that inhibited cell death induced by components of ETI-associated MAP kinase cascades. 4. Isolation of the tomato PRR FLS3 (Hind et al., submitted). FLS3, a novel PRR of the LRR-RLK family that specifically recognizes the flagellinepitope flgII-28 was isolated. FLS3 was shown to bind flgII-28, to require kinase activity for function, to act in concert with BAK1, and to enhance disease resistance to Pseudomonas syringae. 5. Functional analysis of RLCKs of the brassinosteroid signaling kinase (BSK) family.Arabidopsis and tomato BSKs were found to interact with PRRs. In addition, certain ArabidospsisBSK mutants were found to be impaired in PAMP-induced resistance to Pseudomonas syringae. Scientific and agricultural significance: Our research activities discovered and characterized new molecular components of signaling pathways mediating recognition of invading pathogens and activation of immune responses against them. Increased understanding of molecular mechanisms of immunity will allow them to be manipulated by both molecular breeding and genetic engineering to produce plants with enhanced natural defense against disease.
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Sessa, Guido, та Gregory Martin. MAP kinase cascades activated by SlMAPKKKε and their involvement in tomato resistance to bacterial pathogens. United States Department of Agriculture, січень 2012. http://dx.doi.org/10.32747/2012.7699834.bard.
Анотація:
The research problem: Pseudomonas syringae pv. tomato (Pst) and Xanthomonas campestrispv. vesicatoria (Xcv) are the causal agents of tomato bacterial speck and spot diseases, respectively. These pathogens colonize the aerial parts of the plant and cause economically important losses to tomato yield worldwide. Control of speck and spot diseases by cultural practices or chemicals is not effective and genetic sources of resistance are very limited. In previous research supported by BARD, by gene expression profiling we identified signaling components involved in resistance to Xcvstrains. Follow up experiments revealed that a tomato gene encoding a MAP kinase kinase kinase (MAPKKKe) is required for resistance to Xcvand Pststrains. Goals: Central goal of this research was to investigate the molecular mechanisms by which MAPKKKεand associated MAP kinase cascades regulate host resistance. Specific objectives were to: 1. Determine whether MAPKKKεplays a broad role in defense signaling in plants; 2. Identify components of MAP kinase cascades acting downstream of MAPKKKε; 3. Determine the role of phosphorylation-related events in the function of MAPKKKε; 4. Isolate proteins directly activated by MAPKKKε-associatedMAPK modules. Our main achievements during this research program are in the following major areas: 1. Characterization of MAPKKKεas a positive regulator of cell death and dissection of downstream MAP kinase cascades (Melech-Bonfil et al., 2010; Melech-Bonfil and Sessa, 2011). The MAPKKKεgene was found to be required for tomato resistance to Xcvand Pstbacterial strains and for hypersensitive response cell death triggered by different R gene/effector gene pairs. In addition, overexpression analysis demonstrated that MAPKKKεis a positive regulator of cell death, whose activity depends on an intact kinase catalytic domain. Epistatic experiments delineated a signaling cascade downstream of MAPKKKεand identified SIPKK as a negative regulator of MAPKKKε-mediated cell death. Finally, genes encoding MAP kinase components downstream of MAPKKKεwere shown to contribute to tomato resistance to Xcv. 2. Identification of tomato proteins that interact with MAPKKKεand play a role in plant immunity (Oh et al., 2011). We identified proteins that interact with MAPKKKε. Among them, the 14-3-3 protein TFT7 was required for cell death mediated by several R proteins. In addition, TFT7 interacted with the MAPKK SlMKK2 and formed homodimersin vivo. Thus, TFT7 is proposed to recruit SlMKK2 and MAPKKK client proteins for efficient signal transfer. 3. Development of a chemical genetic approach to identify substrates of MAPKKKε-activated MAP kinase cascades (Salomon et al., 2009, 2011). This approach is based on engineering the kinase of interest to accept unnatural ATP analogs. For its implementation to identify substrates of MAPKKKε-activated MAP kinase modules, we sensitized the tomato MAP kinase SlMPK3 to ATP analogs and verified its ability to use them as phosphodonors. By using the sensitized SlMPK3 and radiolabeled N6(benzyl)ATP it should be possible to tag direct substrates of this kinase. 4. Development of methods to study immunity triggered by pathogen-associated molecular patterns (PAMPs) in tomato and N. benthamiana plants (Kim et al., 2009; Nguyen et al. 2010). We developed protocols for measuring various PTI-associatedphenotypes, including bacterial populations after pretreatment of leaves with PAMPs, induction of reporter genes, callose deposition at the cell wall, activation of MAP kinases, and a luciferase-based reporter system for use in protoplasts. Scientific and agricultural significance: Our research activities discovered and characterized a signal transduction pathway mediating plant immunity to bacterial pathogens. Increased understanding of molecular mechanisms of immunity will allow them to be manipulated by both molecular breeding and genetic engineering to produce plants with enhanced natural defense against disease. In addition, we successfully developed new biochemical and molecular methods that can be implemented in the study of plant immunity and other aspects of plant biology.