Relevant bibliographies by topics / Constitutive and induced defence

Academic literature on the topic 'Constitutive and induced defence'

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Published: 10 March 2023

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Journal articles on the topic "Constitutive and induced defence"

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Boots, Mike, and Alex Best. "The evolution of constitutive and induced defences to infectious disease." Proceedings of the Royal Society B: Biological Sciences 285, no. 1883 (July 25, 2018): 20180658. http://dx.doi.org/10.1098/rspb.2018.0658.

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In response to infectious disease, hosts typically mount both constitutive and induced defences. Constitutive defence prevents infection in the first place, while induced defence typically shortens the infectious period. The two routes to defence, therefore, have very different implications not only to individuals but also to the epidemiology of the disease. Moreover, the costs of constitutive defences are likely to be paid even in the absence of disease, while induced defences are likely to incur the most substantial costs when they are used in response to infection. We examine theoretically the evolutionary implications of these fundamental differences. A key result is that high virulence in the parasite typically selects for higher induced defences even if they result in immunopathology leading to very high disease mortality. Disease impacts on fecundity are critical to the relative investment in constitutive and induced defence with important differences found when parasites castrate their hosts. The trade-off between constitutive and induced defence has been cited as a cause of the diversity in defence, but we show that the trade-off alone is unlikely to lead to diversity. Our models provide a framework to examine relative investment in different defence components both experimentally and in the field.
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Hamilton, Ruth, Mike Siva-Jothy, and Mike Boots. "Two arms are better than one: parasite variation leads to combined inducible and constitutive innate immune responses." Proceedings of the Royal Society B: Biological Sciences 275, no. 1637 (January 29, 2008): 937–45. http://dx.doi.org/10.1098/rspb.2007.1574.

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Parasites represent a major threat to all organisms which has led to the evolution of an array of complex and effective defence mechanisms. Common to both vertebrates and invertebrates are innate immune mechanisms that can be either constitutively expressed or induced on exposure to infection. In nature, we find that a combination of both induced and constitutive responses are employed by vertebrates, invertebrates and, to an extent, plants when they are exposed to a parasite. Here we use a simple within-host model motivated by the insect immune system, consisting of both constitutive and induced responses, to address the question of why both types of response are maintained so ubiquitously. Generally, induced responses are thought to be advantageous because they are only used when required but are too costly to maintain constantly, while constitutive responses are advantageous because they are always ready to act. However, using a simple cost function but with no a priori assumptions about relative costs, we show that variability in parasite growth rates selects for a strategy that combines both constitutive and induced defences. Differential costs are therefore not necessary to explain the adoption of both forms of defence. Clearly, hosts are likely to be challenged by variable parasites in nature and this is sufficient to explain why it is optimal to deploy both arms of the innate immune system.
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Miyazaki, Junji, Warwick N. Stiller, Thy T. Truong, Qian Xu, Charles H. Hocart, Lewis J. Wilson, and Iain W. Wilson. "Jasmonic acid is associated with resistance to twospotted spider mites in diploid cotton (Gossypium arboreum)." Functional Plant Biology 41, no. 7 (2014): 748. http://dx.doi.org/10.1071/fp13333.

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The twospotted spider mite (Tetranychus urticae Koch) is capable of dramatically reducing the yield of cotton crops and is often difficult and expensive to control. This study investigated and compared two important plant hormones, jasmonic acid (JA) and salicylic acid (SA), as constitutive and/or induced defence response components in a mite susceptible commercial cotton cultivar, Sicot 71 (Gossypium hirsutum L.) and a resistant diploid cotton BM13H (Gossypium arboreum L.). Foliar application of JA and methyl jasmonate (MeJA) reduced the mite population and leaf damage but application of other potential elicitors, SA and methyl salicylate (MeSA) did not. The concentrations of JA and SA in leaf tissues of induced and non-induced Sicot 71 and BM13H were quantified by liquid chromatography coupled to electrospray ionisation tandem mass spectrometry (LC-ESI-MS/MS). The JA content was constitutively higher in BM13H than Sicot 71 and also highly induced by mite infestation in BM13H but not in Sicot 71. However, SA was not significantly induced in either BM13H or Sicot 71. The expression levels of JA related genes, LOX, AOS and OPR were measured by quantitative PCR and elevated expression levels of JA related genes were detected in mite-infested BM13H. Therefore, JA and MeJA were implicated as key biochemical components in both the constitutive and induced defence responses of BM13H to spider mites.
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Schmidtberg, Henrike, Christian Röhrich, Heiko Vogel, and Andreas Vilcinskas. "A switch from constitutive chemical defence to inducible innate immune responses in the invasive ladybird Harmonia axyridis." Biology Letters 9, no. 3 (June 23, 2013): 20130006. http://dx.doi.org/10.1098/rsbl.2013.0006.

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The harlequin ladybird, Harmonia axyridis , has emerged as a model species for invasion biology, reflecting its remarkable capacity to outcompete native ladybird species when introduced into new habitats. This ability may be associated with its prominent resistance to pathogens and intraguild predation. We recently showed that the constitutive antibacterial activity present in the haemolymph of H. axyridis beetles can be attributed to the chemical defence compound harmonine. Here, we demonstrate that H. axyridis differs from other insects, including the native ladybird Coccinella septempunctata, by reducing rather than increasing the antimicrobial activity of its haemolymph following the injection of bacteria. However, both species produce new or more abundant proteins in the haemolymph, indicating that bacterial challenge induces innate immune responses associated with the synthesis of immunity-related proteins. Our results suggest that H. axyridis beetles can switch from constitutive chemical defence to inducible innate immune responses, supporting hypothesis that inducible antimicrobial peptides protect host beetles against pathogens that survive constitutive defences. These alternative antimicrobial defence mechanisms may reflect a trade-off resulting from fitness-related costs associated with the simultaneous synthesis of harmonine and antimicrobial peptides/proteins.
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Rodríguez-Romero, Manuela, Alejandro Gallardo, Andrea Pérez, and Fernando Pulido. "Interactive effects of biotic stressors and provenance on chemical defence induction by holm oak (Quercus ilex)." Trees 36, no. 1 (December 10, 2021): 227–40. http://dx.doi.org/10.1007/s00468-021-02201-z.

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Abstract Key Message The patterns of induced chemical defences in Quercus ilex leaves are specific to the biotic stress factor that causes them. Interactive effects between stressors depend on provenance. Abstract Quercus forests are suffering serious decline worldwide, closely linked to the consequences of climate change. The increase of biotic stressors threatens the survival of the holm oak (Quercus ilex), a dominant tree species in the Mediterranean Basin. A better understanding of its resistance mechanisms is urgently required to enable a better control of its decline. In this work, the ability of holm oaks from six Iberian provenances to respond to multiple biotic damage is studied through an analysis of their induced chemical defence patterns. Using 2016 seedlings established in a common garden trial (6 regions × 12 families/region × 7 seedlings/family × 4 treatments), biotic damage was induced at the root level (by infection with the widespread pathogen Phytophthora cinnamomi) and at the above-ground level (by mechanical defoliation). The levels of constitutive and induced total phenols, total tannins and condensed tannins were measured. Results showed that (1) the defensive chemical patterns present significant local and geographical variation, (2) survival to stress is more related to constitutive defences than induced ones, (3) the induced response is stressor-specific, and (4) there is an interactive effect amongst stressors whose sign (induction/inhibition) depends on the provenance. These findings on biotic stressor effects on the chemical defences and survival of holm oak can contribute to the development of genetic material selection programs in the integrated control of the widespread decline of Quercus.
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Ruiz, N., D. Ward, and D. Saltz. "Calcium oxalate crystals in leaves of Pancratium sickenbergeri : constitutive or induced defence?" Functional Ecology 16, no. 1 (February 2002): 99–105. http://dx.doi.org/10.1046/j.0269-8463.2001.00594.x.

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JOLIVET, CÉLINE, and GIORGINA BERNASCONI. "Experimental analysis of constitutive and induced defence in a plant?seed?predator system." Functional Ecology 20, no. 6 (December 2006): 966–72. http://dx.doi.org/10.1111/j.1365-2435.2006.01196.x.

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Lindgren, B. S., and K. F. Raffa. "Evolution of tree killing in bark beetles (Coleoptera: Curculionidae): trade-offs between the maddening crowds and a sticky situation." Canadian Entomologist 145, no. 5 (June 11, 2013): 471–95. http://dx.doi.org/10.4039/tce.2013.27.

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AbstractBark beetles (Coleoptera: Curculionidae: Scolytinae) play important roles in temperate conifer ecosystems, and also cause substantial economic losses. Although their general life histories are relatively similar, different species vary markedly in the physiological condition of the hosts they select. Most of ∼6000 known species colonise dead or stressed trees, a resource they share with a large diversity of insects and other organisms. A small number of bark beetle species kill healthy, live trees. These few are of particular interest as they compete directly with humans for resources. We propose that tree killing evolved when intense interspecific competition in the ephemeral, scarce resource of defence-impaired trees selected for genotypes that allowed them to escape this limitation by attacking relatively healthy trees. These transitions were uncommon, and we suggest they were facilitated by (a) genetically and phenotypically flexible host selection behaviours, (b) biochemical adaptations for detoxifying a wide range of defence compounds, and (c) associations with symbionts, which together aided bark beetles in overcoming formidable constitutive and induced host defences. The ability to detoxify terpenes influenced the evolutionary course of pheromonal communication. Specifically, a mate attraction system, which was exploited by intraspecific competitors in locating poorly defended hosts, became a system of cooperative attack in which emitters benefit from the contributions responders make in overcoming defence. This functional shift in communication was driven in part by linkage of beetle semiochemistry to host defence chemistry. Behavioural and phenological adaptations also improved the beetles’ abilities to detect when tree defences are impaired, and, where compatible with life history adaptations to other selective forces, for flight to coincide with seasonally predictable host stress agents. We propose a conceptual model, whereby the above mechanisms enable beetles to concentrate on those trees that offer an optimal trade-off between host defence and interspecific competition, along dynamic gradients of tree vigour and stand-level beetle density. We offer suggestions for future research on testing elements of this model.
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Schulte, Rebecca D., Barbara Hasert, Carsten Makus, Nico K. Michiels, and Hinrich Schulenburg. "Increased responsiveness in feeding behaviour of Caenorhabditis elegans after experimental coevolution with its microparasite Bacillus thuringiensis." Biology Letters 8, no. 2 (August 31, 2011): 234–36. http://dx.doi.org/10.1098/rsbl.2011.0684.

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Immune responses, either constitutive or induced, are costly. An alternative defence strategy may be based on behavioural responses. For example, avoidance behaviour reduces contact with pathogens and thus the risk of infection as well as the requirement of immune system activation. Similarly, if pathogens are taken up orally, preferential feeding of pathogen-free food may be advantageous. Behavioural defences have been found in many animals, including the nematode Caenorhabditis elegans . We here tested nematodes from a laboratory based evolution experiment which had either coevolved with their microparasite Bacillus thuringiensis (BT) or evolved under control conditions. After 48 generations, coevolved populations were more sensitive to food conditions: in comparison with the controls, they reduced feeding activity in the presence of pathogenic BT strains while at the same time increasing it in the presence of non-pathogenic strains. We conclude that host–parasite coevolution can drive changes in the behavioural responsiveness to bacterial microbes, potentially leading to an increased defence against pathogens.
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Martinez-Swatson, Karen, Rasmus Kjøller, Federico Cozzi, Henrik Toft Simonsen, Nina Rønsted, and Christopher Barnes. "Exploring evolutionary theories of plant defence investment using field populations of the deadly carrot." Annals of Botany 125, no. 5 (October 31, 2019): 737–50. http://dx.doi.org/10.1093/aob/mcz151.

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Abstract Background and Aims There are a number of disparate models predicting variation in plant chemical defences between species, and within a single species over space and time. These can give conflicting predictions. Here we review a number of these theories, before assessing their power to predict the spatial–temporal variation of thapsigargins between and within populations of the deadly carrot (Thapsia garganica). By utilizing multiple models simultaneously (optimum defence theory, growth rate hypothesis, growth–differentiation balance hypothesis, intra–specific framework and resource exchange model of plant defence), we will highlight gaps in their predictions and evaluate the performance of each. Methods Thapsigargins are potent anti-herbivore compounds that occur in limited richness across the different plant tissues of T. garganica, and therefore represent an ideal system for exploring these models. Thapsia garganica plants were collected from six locations on the island of Ibiza, Spain, and the thapsigargins quantified within reproductive, vegetative and below-ground tissues. The effects of sampling time, location, mammalian herbivory, soil nutrition and changing root-associated fungal communities on the concentrations of thapsigargins within these in situ observations were analysed, and the results were compared with our model predictions. Key Results The models performed well in predicting the general defence strategy of T. garganica and the above-ground distribution of thapsigargins, but failed to predict the considerable proportion of defences found below ground. Models predicting variation over environmental gradients gave conflicting and less specific predictions, with intraspecific variation remaining less understood. Conclusion Here we found that multiple models predicting the general defence strategy of plant species could likely be integrated into a single model, while also finding a clear need to better incorporate below-ground defences into models of plant chemical defences. We found that constitutive and induced thapsigargins differed in their regulation, and suggest that models predicting intraspecific defences should consider them separately. Finally, we suggest that in situ studies be supplemented with experiments in controlled environments to identify specific environmental parameters that regulate variation in defences within species.
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Dissertations / Theses on the topic "Constitutive and induced defence"

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Villari, Caterina. "Fungi associated with the pine engraver beetle Ips acuminatus and their interactions with the host tree." Doctoral thesis, Università degli studi di Padova, 2012. http://hdl.handle.net/11577/3422532.

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Conifer bark beetles are typically associated with complexes of fungi with which they can display different functional relationships. Some of the fungi, generally non phytopathogenic, are known to have a directly mutualistic interaction with the beetles, serving as nourishment to the larvae. Other associated fungi are thought to be involved in the process of exhausting plant defenses, which is a necessary step for the insects to overcome host tree resistance and colonize the plant. In the latter case, bark beetle-associated fungi are often tree pathogenic species belonging to the morphologically homogenous group of the ophiostomatoid fungi, also referred to as ‘blue-stain’ fungi. In spite of the great interest the bark beetle-fungi symbiosis has gained in time, many fundamental aspects of this relationship are still widely debated, as for instance the degree of dependence of bark beetles on the blue-stain fungi in order to succeed their establishment in the host plant. In this thesis I addressed the fungal community associated with the pine engraver beetle Ips acuminatus (Gyll.), a small bark beetle infesting thin bark of Scots pine (Pinus sylvestris L.) and that has been recently reported as pest in many alpine forests. I. acuminatus associated fungal community includes the obligate nutritional fungus Hyalorhinocladiella macrospora (Franke-Grosm.) Harr. and a specific blue-stain fungus which is consistently associated with the vector, but which identity is still uncertain. Early reports describe it as Ophiostoma clavatum Math.-Käärik, while a later research reported O. brunneo-ciliatum Math. instead. Objectives of the thesis were to determine the identity of the blue-stain fungi associated with I. acuminatus, and to investigate the fungal community interactions with the host plant, in order to better define the functional relationships occurring between the bark beetle and the associated fungi, and therefore contribute to the attempts in understanding ecology and population dynamics of this damaging species. In the first work a blue-stain fungus associated with I. acuminatus specimens collected in Italy and Sweden was isolated and identified. The identification of the species was achieved with both the support of morphological methods and DNA sequence-based methods, and the species resulted to be O. clavatum, in agreement with the first researches focused on I. acuminatus associated fungi. In the second work, to clearly assess which of the previously described Ophiostoma species was the main blue-stain fungus associated with the pine engraver beetle, three loop-mediated isothermal amplification (LAMP) assays were developed and employed in a survey which has covered six Italian populations of I. acuminatus. The results confirmed that the identity of the blue-stain fungus more consistently associated with I. acuminatus in the Italian Alps is O. clavatum, while O. brunneo-ciliatum was not detected in any of the samples. Results of this study showed also that the occurrence of O. clavatum varies accordingly to the population dynamic phase of the vector, and is slightly lower in the outbreak populations. In the third work, the local and systemic defense responses of Scots pine against both the nutritional and the blue-stain fungi were characterized by identifying and quantifying terpenoids, phenolic compounds, and lignin. Results indicated that Scots pine has a generic, rather than specific, induced response. The fact that the nutritional and the blue-stain fungi triggered comparable induced defense responses suggests that even a non-pathogenic fungus may participate in exhausting host plant defenses, indirectly assisting in the beetle establishment process. This finding contributes to the further development of current theories on the role of associated fungal complexes in bark beetle ecology. In the last work, correlation patterns within constitutive defense secondary metabolites of Scots pine and potential trade-offs between constitutive concentration and inducible variation of individual chemical compounds were tested. Results revealed that different compounds display different behaviors, but no overall negative associations between defensive traits were found. On the whole, the four contributions of this thesis provide suggestions for a revaluation of one of the current theories on the role of associated fungi in bark beetles host establishment, and hints to understand the role of associated fungi in the population dynamics of bark beetles. Moreover, they clarify some aspects of Scots pine defense mechanisms, highlighting its competitiveness.
Gli scolitidi delle conifere sono insetti spesso associati ad un complesso di funghi con i quali possono instaurare differenti interazioni ecologiche. Alcuni di questi funghi, generalmente non fitopatogeni, sono coinvolti in un’interazione mutualistica diretta e vengono utilizzati come nutrimento per le larve del vettore. Altri funghi associati, invece, sono ritenuti coinvolti nel processo di esaurimento delle difese della pianta, che per l’insetto è uno dei passaggi necessari per superare la resistenza dell’ospite e poterlo quindi colonizzare. In quest’ultimo caso, i funghi associati sono di norma specie patogene appartenenti al gruppo morfologico dei funghi ophiostomatoidi, noti anche come ‘funghi di azzurramento’. Nonostante l’interesse che la simbiosi tra scolitidi e funghi ha riscosso nel tempo, molti degli aspetti fondamentali di questa interazione sono ancora discussi, come ad esempio il grado di dipendenza degli insetti vettori dai loro simbionti nelle fasi di colonizzazione della pianta ospite. In questa tesi è stata presa in considerazione la comunità fungina associata a Ips acuminatus (Gyll.), un piccolo scolitide che attacca di preferenza le parti del tronco del pino silvestre (Pinus sylvestris L.) con corteccia sottile, e che di recente ha causato numerose infestazioni in varie zone distribuite sull’arco alpino. Una delle specie che fanno parte della comunità fungina associata ad I. acuminatus è il simbionte alimentare Hyalorhinocladiella macrospora (Franke-Grosm.) Harr. Fa inoltre parte del complesso anche uno specifico fungo di azzurramento costantemente associato al vettore, ma la cui identità non è ancora ben definita. Le prime segnalazioni lo descrivono come Ophiostoma clavatum Math.-Käärik, mentre ricerche successive riportano O. brunneo-ciliatum Math. Gli obiettivi che questa tesi si è prefissa sono stati determinare l’effettiva identità del fungo di azzurramento associato ad I. acuminatus, ed indagare le interazioni del complesso fungino con la pianta ospite, al fine di definire meglio le relazioni che intercorrono tra scolitidi e fungi associati, e poter quindi contribuire ai tentativi di chiarire l’ecologia e la dinamica di popolazione di questo insetto dannoso. Nel primo lavoro sono stati descritti l’isolamento e l’identificazione di una specie fungina isolata da individui di I. acuminatus raccolti in Italia e in Svezia. L’identificazione della specie è avvenuta sia grazie all’osservazione delle caratteristiche morfologiche sia mediante un approccio di tipo molecolare. La specie è risultata essere O. clavatum, come era stato indicato nelle prime segnalazioni riguardanti i funghi associati ad I. acuminatus. Nel secondo lavoro sono stati descritti la messa punto e l’utilizzo di tre sonde molecolari per loop-mediated isothermal amplification (LAMP), con l’obiettivo di determinare quale delle due specie del genere Ophiostoma sopracitate fosse effettivamente il fungo maggiormente associato a I. acuminatus nell’arco alpino. I risultati, riguardanti sei popolazioni italiane dell’insetto, hanno confermato che la specie maggiormente presente è O. clavatum, mentre O. brunneo-ciliatum non è mai stata rilevata. I risultati di questo studio hanno mostrato anche che la frequenza di associazione di I. acuminatus con O. clavatum varia a seconda della fase epidemica, ed è minore nei nuclei di infestazione rispetto alle popolazioni endemiche. Nel terzo lavoro sono state caratterizzate le risposte sia locali sia sistemiche del pino silvestre alla colonizzazione da parte del simbionte alimentare e del fungo di azzurramento, identificando e quantificando alcuni metaboliti secondari, come terpeni, fenoli e lignina. I risultati hanno mostrato che il pino silvestre risponde in maniera generica anziché specifica all’induzione. Il fatto inoltre che il simbionte alimentare e il fungo di azzurramento abbiano stimolato una risposta simile di loro suggerisce che anche un fungo non patogeno possa partecipare al processo di esaurimento delle difese della pianta, assistendo quindi l’insetto nelle fasi di colonizzazione dell’ospite. Questo risultato contribuisce quindi allo sviluppo delle attuali teorie sul ruolo dei funghi associati nell’ecologia degli scolitidi. Nell’ultimo lavoro sono state studiate le correlazioni tra i metaboliti secondari delle difese costitutive del pino silvestre, e le correlazioni tra la concentrazione costitutiva e la variazione indotta dei singoli composti. I risultati hanno messo in evidenza una differenziazione di comportamento tra composti e l’assenza in generale di una correlazione inversa tra i tipi diversi di difese, al contrario di quanto previsto da alcune teorie. Nel complesso, i quattro contributi di questa tesi suggeriscono la rivalutazione di una delle attuali teorie sul ruolo dei funghi associati nella colonizzazione dell’ospite da parte degli scolitidi, e forniscono degli spunti per la comprensione del ruolo dei funghi associati nella dinamica di popolazione del vettore. Chiariscono inoltre alcuni degli aspetti dei meccanismi di difesa del pino silvestre, mettendo in evidenza la sua competitività.
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Sinclair, Steven J. "QPRTase : a wound-induced defence gene in Nicotiana." Monash University, School of Biological Sciences, 2003. http://arrow.monash.edu.au/hdl/1959.1/6571.

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Warner, Simon A. J. "Cloning and characterization of an asparagus wound-induced gene." Thesis, University of Leicester, 1992. http://hdl.handle.net/2381/35363.

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Following previous studies, Asparagus officinalis single cell suspensions were hypothesized to be a rich source of wound-inducible mRNAs. A previously isolated clone, DDl-34, was shown to hybridize to wound-inducible transcript. This sequence was used to isolate the AoPR1 (Asparagus officinalis Pathogenesis Related cDNA clone 1). Data from the isolation and analysis of genomic clones hybridizing to DDl-34 probe suggested that these clones were unlikely to contain the upstream regulatory sequences of the AoPR1 gene and that the genomic arrangement of these sequences is complex. Inverse polymerase chain reactions (IPCR) were used to amplify AoPR1 genic sequences directly from the asparagus genome. Two products were cloned and sequenced, demonstrating that the correct sequences, upstream and downstream of the primers, had been amplified. The downstream IPCR product's sequence overlaps with AoPR1 coding sequence and contains an intron sequence. The upstream IPCR product partially overlaps with the start of AoPR1 coding sequence and was successfully used in transcript mapping experiments. Translational fusions were constructed between this fragment and the -glucuronidase (gus) reporter gene. GUS analysis demonstrated that this fragment, containing the AoPR1 promoter, was sufficient to drive wound-inducible transcription in transgenic tobacco. A smaller upstream fragment was insufficient to drive wound-inducible transcription. GUS expression was also detectable in tissues such as the xylem parenchyma, mature pollen and coloured regions of the petal. AoPR1-gus transgene expression correlates with the spatial expression patterns of phenylpropanoid biosynthesis pathway genes. The nature of the fusion suggested that the AoPR1 protein is intracellular. This is the first example of the cloning and analysis of a monocotyledon gene belonging to the 'intracellular pathogenesis related protein' class. The analysis and application of AoPR1 sequences are discussed.
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Venkatasubramaniam, Shyam. "Constitutive Modeling of Poly(Ethylene Terephthalate)." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1417444300.

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Singh, Jasber. "The plasma membrane H⁺-TPase and pathogen-induced plant defence." Thesis, Lancaster University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.423560.

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Tang, M. "Elicitor-induced defence response and signal mechanisms in Medicago sativa L." Thesis, Swansea University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.639158.

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In this study, the responses and signal mechanisms were explored with a model system, concerning the interactions between lucerne suspension cells (Medicago sativa L., cv. Kabul) and elicitor either from avirulent (V2) or virulent (V1) isolate of Verticillium, alboatrum. V2 elicitor induced a two-phase of H2O2 accumulation in the cell cultures. Activation of defence expression led to an increase in PAL activity, phytoalexin accumulation and deposition of phenolic polymers. However, activities of antioxidant enzymes, such as catalase, peroxidases, glucanase, glutathione reductase, did not show obvious increase within 24 h after treatment with the elicitor. Glutathione S-transferase activity increased after 1st oxidative burst. V1 elicitor induced similar defence responses as V2 did, but a stronger response was observed when the same concentration of elicitor was used, confirming that Kabul is a resistance cultivar to V. albo-atrum. Ca2+ influx is necessary for oxidative burst, PAL activity and phytoalexin accumulation. Either blocking Ca2+ channel by La3+ or reduction of extracellular Ca2+ amount by EGTA, had an important inhibition on oxidative burst, PAL activity and phytoalexin accumulation. Intracellular Ca2+ also played a role in downstream signalling. Intracellular Ca2+ inhibitors. TBM-8 and Ruthenium red, strongly inhibited the PAL activity and phytoalexin accumulation. Oxidative burst has a relation with defence expression. An NADPH oxidase inhibitor, diphenyleneiodonium (DPI), which inhibited oxidative burst effectively, also inhibited PAL activity and phytoalexin accumulation. However, DCN, an inhibitor of peroxidase, also inhibited and oxidative burst, PAL activity and phytoalexin accumulated in micromolar range. Oxidative burst with superoxide-origin is related to defence activation. The H2O2 itself did not stimulate an activation of PAL activity. Addition of superoxide dismutase (SOD) stimulated an increase in H2O2 accumulation. Microsomal membranes are capable of superoxide synthesis when NADPH/NADH was used as electron donor, which was DPI-sensitive. This enzyme activity increased after treatment of the cell cultures with elicitor.
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Stirrup, Timothy J. "Induced defence in wild cabbage : integrating genes, volatiles & insect behaviour." Thesis, University of Southampton, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.439371.

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Gibberd, R. M. "Wound-induced plant responses and their consequences for insect grazing." Thesis, University of Southampton, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378189.

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Dean, Edward Timothy Richard. "An isotropic transformations soil constitutive model with induced anisotropy in axial deformation events." Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293200.

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Bechtold, David Alexander. "Localization of constitutive and hyperthermia-induced heat shock proteins to synapses of the rat brain." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0026/MQ50477.pdf.

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Books on the topic "Constitutive and induced defence"

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Staroszczyk, Ryszard. Constitutive modelling of creep induced anisotropy of ice. Gdańsk: Institute of Hydro-Engineering of the Polish Academy of Sciences, 2004.

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Walters, Dale, Adrian Newton, and Gary Lyon, eds. Induced Resistance for Plant Defence. Oxford, UK: Blackwell Publishing, 2007. http://dx.doi.org/10.1002/9780470995983.

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Derek, Chadwick, Goode Jamie, Novartis Foundation, and Symposium on Insect-Plant Interactions and Induced Plant Defence (1998 : Novartis Foundation), eds. Insect-plant interactions and induced plant defence. Chichester: Wiley, 1999.

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Bechtold, David Alexander. Localization of constitutive and hyperthermia-induced heat shock proteins to synapses of the rat brain. Ottawa: National Library of Canada, 2000.

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Chadwick, Derek J., and Jamie A. Goode, eds. Novartis Foundation Symposium 223 - Insect-Plant Interactions and Induced Plant Defence. Chichester, UK: John Wiley & Sons, Ltd., 2007. http://dx.doi.org/10.1002/9780470515679.

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Walters, Dale, Adrian C. Newton, and Gary Lyon. Induced resistance for plant defence: A sustainable approach to crop protection. Hoboken, NJ: John Wiley & Sons Inc., 2015.

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Dale, Walters, Newton Adrian C, and Lyon Gary, eds. Induced resistance for plant defence: A sustainable approach to crop protection. Oxford, UK: Blackwell Pub., 2007.

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Borges, Andrés A., and Luisa M. Sandalio, eds. Induced Resistance for Plant Defence. Frontiers Media SA, 2016. http://dx.doi.org/10.3389/978-2-88919-925-9.

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Goode, Jamie A., and Derek J. Chadwick. Insect-Plant Interactions and Induced Plant Defence. Wiley & Sons, Incorporated, John, 2009.

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Goode, Jamie A., and Derek J. Chadwick. Insect-Plant Interactions and Induced Plant Defence. Wiley & Sons, Incorporated, John, 2008.

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Book chapters on the topic "Constitutive and induced defence"

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Wood, David Muir. "Constitutive Modelling." In Mechanical Behaviour of Soils Under Environmentally Induced Cyclic Loads, 137–226. Vienna: Springer Vienna, 2012. http://dx.doi.org/10.1007/978-3-7091-1068-3_2.

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van Dam, Nicole M., and Sheila K. Bhairo-Marhé. "Induced chemical defence in Cynoglossum officinale." In Proceedings of the 8th International Symposium on Insect-Plant Relationships, 79–82. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-1654-1_24.

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Denora, I., and C. Marano. "Fracture behavior of filled elastomers: How do strain induced softening and its thermally induced recovery affect the fracture toughness?" In Constitutive Models for Rubber XII, 321–27. London: CRC Press, 2022. http://dx.doi.org/10.1201/9781003310266-53.

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Poudel, R., M. Itskov, S. Charlès, J. B. Le Cam, and V. N. Khiêm. "Numerical prediction of strain-induced crystallization under complex loadings." In Constitutive Models for Rubber XII, 145–50. London: CRC Press, 2022. http://dx.doi.org/10.1201/9781003310266-24.

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Garcion, Christophe, Olivier Lamotte, Jean-Luc Cacas, and Jean-Pierre Métraux. "Mechanisms of Defence to Pathogens: Biochemistry and Physiology." In Induced Resistance for Plant Defense, 106–36. Chichester, UK: John Wiley & Sons, Ltd, 2014. http://dx.doi.org/10.1002/9781118371848.ch6.

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Buisson, M., E. Patoor, and M. Berveiller. "Constitutive Equations for Deformations Induced by Interfacial Motions." In Anisotropy and Localization of Plastic Deformation, 536–39. Dordrecht: Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-011-3644-0_124.

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Ishikawa, H., and K. Sasaki. "Constitutive Modeling of Cyclic Plasticity Considering Induced Anisotropy." In Computational Mechanics ’86, 731–36. Tokyo: Springer Japan, 1986. http://dx.doi.org/10.1007/978-4-431-68042-0_102.

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Duncan, A. M., K. Akutagawa, J. L. Ramier, and J. J. C. Busfield. "Anisotropy of nitrile butadiene rubber induced by thermal ageing at fixed strain." In Constitutive Models for Rubber XII, 434–39. London: CRC Press, 2022. http://dx.doi.org/10.1201/9781003310266-71.

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Moreira, Xoaquín, Rafael Zas, and Luis Sampedro. "Methyl Jasmonate as Chemical Elicitor of Induced Responses and Anti-Herbivory Resistance in Young Conifer Trees." In Plant Defence: Biological Control, 345–62. Dordrecht: Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-94-007-1933-0_15.

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Cheung, Y. K., J. H. W. Lee, and C. W. Li. "Flow Induced by a Fanned Out Jet Group." In Transient/Dynamic Analysis and Constitutive Laws for Engineering Materials, 381–88. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-009-3655-3_42.

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Conference papers on the topic "Constitutive and induced defence"

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Saphiannikova, Marina, Vladimir Toshchevikov, Jaroslav Ilnytskyi, and Gert Heinrich. "Photo-induced deformation of azobenzene polymers: theory and simulations." In SPIE Security + Defence, edited by Roberto Zamboni, François Kajzar, Attila A. Szep, Colin Lewis, Douglas Burgess, Mark T. Gruneisen, Miloslav Dusek, and John G. Rarity. SPIE, 2011. http://dx.doi.org/10.1117/12.897375.

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Gustafsson, Ove K. S., Markus Henriksson, and Lars Sjöqvist. "Wall induced turbulence distortions of optical measurements." In SPIE Europe Security + Defence, edited by Gary W. Kamerman, Ove K. Steinvall, Keith L. Lewis, Richard C. Hollins, Thomas J. Merlet, Gary J. Bishop, and John D. Gonglewski. SPIE, 2009. http://dx.doi.org/10.1117/12.830606.

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Duschek, Frank, Carsten Pargmann, Karin Grünewald, and Jürgen Handke. "Stand-off detection at the DLR laser test range applying laser-induced breakdown spectroscopy." In Security + Defence, edited by Colin Lewis, Douglas Burgess, Roberto Zamboni, François Kajzar, and Emily M. Heckman. SPIE, 2010. http://dx.doi.org/10.1117/12.864440.

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Harder, James A., and Michaelene W. Sprague. "Canopy induced aberration correction in airborne electro-optical imaging systems." In SPIE Security + Defence. SPIE, 2011. http://dx.doi.org/10.1117/12.898276.

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Saphiannikova, M., V. Toshchevikov, and J. Ilnytskyi. "Nanoscopic actuators in light-induced deformation of glassy azo-polymers." In SPIE Security + Defence, edited by Roberto Zamboni, Francois Kajzar, Attila A. Szep, Douglas Burgess, and Gari Owen. SPIE, 2013. http://dx.doi.org/10.1117/12.2031775.

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Hess, Peter. "Laser-Induced Deposition of Amorphous Silicon: Relations between Chemical Processing and Performance." In The Microphysics of Surfaces: Beam-Induced Processes. Washington, D.C.: Optica Publishing Group, 1991. http://dx.doi.org/10.1364/msbip.1991.tuc1.

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Hydrogenated, amorphous silicon (a-Si:H) is of great interest for thin film devices used, for example, for the transformation of photon energy and as semiconductor material. Important applications are thin film solar cells, thin film transistors for liquid crystal displays, photoreceptors for electrophotography and laser printing and image sensors. To improve and optimize the properties of the material for specific applications it is necessary to control the formation of the three dimensional network during the solidification process ("bandgap engineering"). Incorporation of hydrogen into the network reduces the density of defects near the middle of the bandgap ("gap states"). For optimal performance a specific binding configuration should be realized. Distortions in the metastable silicon network, especially in the bond angle, are believed to be responsible for the tail states at the bandgap edges. Since these defect states constitute traps for charge carriers and thus lower their mobilities it is necessary to reduce the density of these states. To achieve an efficient control of the deposition process in this direction, detailed molecular information on the dynamic processes leading to solidification and on the structure-performance relationship is needed.
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G. Rodrigo, Sergio, and L. Martín-Moreno. "Molecular detection with terahertz waves based on absorption-induced transparency metamaterials." In SPIE Security + Defence, edited by Neil A. Salmon and Sherif S. Ahmed. SPIE, 2016. http://dx.doi.org/10.1117/12.2241385.

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Schwarz, Bastian, Gunnar Ritt, Michael Körber, and Bernd Eberle. "Laser-induced damage threshold of camera sensors and micro-opto-electro-mechanical systems." In SPIE Security + Defence, edited by David A. Huckridge, Reinhard Ebert, and Stephen T. Lee. SPIE, 2016. http://dx.doi.org/10.1117/12.2241057.

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Toshchevikov, Vladimir P., Marina Saphiannikova Grenzer, and Gert Heinrich. "Effects of the liquid-crystalline order on the light-induced deformation of azobenzene elastomers." In SPIE Security + Defence, edited by Roberto Zamboni, François Kajzar, and Attila A. Szep. SPIE, 2012. http://dx.doi.org/10.1117/12.970309.

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Sunchugasheva, E. S., A. A. Ionin, D. V. Mokrousova, L. V. Seleznev, D. V. Sinitsyn, Yu E. Geints, and A. A. Zemlyanov. "Remote sensing for oil products on water surface via fluorescence induced by UV filaments." In SPIE Security + Defence, edited by Gary Kamerman and Ove Steinvall. SPIE, 2016. http://dx.doi.org/10.1117/12.2241533.

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Reports on the topic "Constitutive and induced defence"

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Maiti, A., T. H. Weisgraber, and L. N. Dinh. Radiation-induced aging of PDMS Elastomer TR-55: a summary of constitutive, mesoscale, and population-based models. Office of Scientific and Technical Information (OSTI), November 2016. http://dx.doi.org/10.2172/1338168.

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Krempl, Erhard. Inelastic constitutive equations: deformation induced anisotropy and the behavior at high homologous temperature. Final report January 1, 1996 through June 30, 1999. Office of Scientific and Technical Information (OSTI), June 2000. http://dx.doi.org/10.2172/761118.

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O'Neill, Sharman, Abraham Halevy, and Amihud Borochov. Molecular Genetic Analysis of Pollination-Induced Senescence in Phalaenopsis Orchids. United States Department of Agriculture, 1991. http://dx.doi.org/10.32747/1991.7612837.bard.

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The project investigated the molecular genetic and biochemical basis of pollination-induced senescence of Phalaenopsis flowers. This experimental system offered unique advantages in that senescence is strictly regulated by pollination, providing the basis to experimentally initiate and synchronize senescence in populations of flowers. The postpollination syndrome in the Phalaenopsis orchid system was dissected by investigating the temporal and spatial regulation of ACC synthase gene expression. In the stigma, pollen-borne auxin induces the expression of the auxin-regulated ACC synthase (PS-ACS2) gene, resulting in ACC synthesis within 1 h following pollination. Newly formed ACC is oxidized by basal constitutive ACC oxidase to ethylene, which then induces the expression of the ethylene-regulated ACC synthase(PS-ACS1) and oxidase (ACO1) genes for further autocatalytic production of ethylene. It is speculated that during the 6-h period following pollination, emasculation leads to the production or release of a sensitivity factor that sensitizes the cells of the stigma to ethylene. ACC and ethylene molecules are translocated from the stigma to the labellum and perianth where ethylene induces the expression of PS-ACS1 and ACO1 resulting in an increased production of ACC and ethylene. Organ-localized ethylene is responsible for inrolling and senescence of the labellum and perianth. The regulation of ethylene sensitivity and signal transduction events in pollinated flowers was also investigated. The increase in ethylene sensitivity appeared in both the flower column and the perianth, and was detected as early as 4 h after pollination. The increase in ethylene sensitivity following pollination was not dependent on endogenous ethylene production. Application of linoleic and linoleic acids to Phalaenopsis and Dendrobium flowers enhanced their senescence and promoted ethylene production. Several major lipoxygenase pathway products including JA-ME, traumatic acid, trans-2-hexenal and cis-3-hexenol, also enhanced flower senescence. However, lipoxygenase appears to not be directly involved in the endogenous regulation of pollination-induced Phalaenopsis and Dendrobium flower senescence. The data suggest that short-chain saturated fatty acids may be the ethylene "sensitivity factors" produced following pollination, and that their mode of action involves a decrease in the order of specific regions i the membrane lipid bilayer, consequently altering ethylene action. Examination of potential signal transduction intermediates indicate a direct involvement of GTP-binding proteins, calcium ions and protein phosphorylation in the cellular signal transduction response to ethylene following pollination. Modulations of cytosolic calcium levels allowed us to modify the flowers responsiveness to ethylene.
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Chejanovsky, Nor, and Bruce A. Webb. Potentiation of pest control by insect immunosuppression. United States Department of Agriculture, July 2004. http://dx.doi.org/10.32747/2004.7587236.bard.

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Our original aims were to elucidate the mechanisms through which the immunosuppressive insect virus, the Campoletis sonorensis polydnavirus (CsV) promotes replication of a well-characterized pathogenic virus, the Autographa californica multiple nucleopolyhedrovirus (AcMNPV) in hosts that are mildly or non-permissive to virus replication. According to the BARD panels criticism we modified our short-term goals (see below). Thus, in this feasibility study (one-year funding) we aimed to show that: 1. S. littoralis larvae mount an immune response against a baculovirus infection. 2. Immunosuppression of an insect pest improves the ability of a viral pathogen (a baculovirus) to infect the pest. 3. S. littoralis cells constitute an efficient tool to study some aspects of the anti- viral immune response. We achieved the above objectives by: 1. Finding melanized viral foci upon following the baculoviral infection in S . littoralis larvae infected with a polyhedra - positive AcMNPV recombinant that expressed the GFP gene under the control of the Drosophila heat shock promoter. 2. Studying the effect of AcMNPV-infection in S . littoralis immunosuppressed by parasitation with the Braconidae wasp Chelonus inanitus that bears the CiV polydna virus, that resulted in higher susceptibility of S. littoralis to AcMNPV- infection. 3. Proving that S. littoralis hemocytes resist AcMNPV -infection. 4. Defining SL2 as a granulocyte-like cell line and demonstrating that as littoralis hemocytic cell line undergoes apoptosis upon AcMNPV -infection. 5. Showing that some of the recombinant AcMNPV expressing the immuno-suppressive polydna virus CsV- vankyrin genes inhibit baculoviral-induced lysis of SL2 cells. This information paves the way to elucidate the mechanisms through which the immuno- suppressive polydna insect viruses promote replication of pathogenic baculoviruses in lepidopteran hosts that are mildly or non-permissive to virus- replication by: - Assessing the extent to which and the mechanisms whereby the immunosuppressive viruses, CiV and CsV or their genes enhance AcMNPV replication in polydnavirus- immunosuppressed H. zea and S. littoralis insects and S. littoralis cells. - Identifying CiV and CsV genes involved in the above immunosuppression (e.g. inhibiting cellular encapsulation and disrupting humoral immunity). This study will provide insight to the molecular mechanisms of viral pathogenesis and improve our understanding of insect immunity. This knowledge is of fundamental importance to controlling insect vectored diseases of humans, animals and plants and essential to developing novel means for pest control (including baculoviruses) that strategically weaken insect defenses to improve pathogen (i.e. biocontrol agent) infection and virulence.
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Tucker, Mark L., Shimon Meir, Amnon Lers, Sonia Philosoph-Hadas, and Cai-Zhong Jiang. Elucidation of signaling pathways that regulate ethylene-induced leaf and flower abscission of agriculturally important plants. United States Department of Agriculture, January 2012. http://dx.doi.org/10.32747/2012.7597929.bard.

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The Problem: Abscission is a highly regulated process, occurring as a natural terminal stage of development, in which various organs are separated from the parent plant. In most plant species, the process is initiated by a decrease in active auxin in the abscission zone (AZ) and an increase in ethylene, and may be accelerated by postharvest or environmental stresses. Another potential key regulator in abscission is IDA (Inflorescence Deficient in Abscission), which was identified as an essential peptide signal for floral organ abscission in Arabidopsis. However, information is still lacking regarding the molecular mechanisms integrating all these regulators. In our previous BARD funded research we made substantial progress towards understanding these molecular events in tomato, and the study is still in progress. We established a powerful platform for analysis of genes for regulatory proteins expressed in AZ. We identified changes in gene expression for several transcription factors (TFs) directly linked to ethylene and auxin signaling and several additional regulatory proteins not so obviously linked to these hormones. Moreover, we demonstrated using a virus-induced gene silencing (VIGS) assay that several play a functional role in the onset of abscission. Based on these results we have selected 14 genes for further analysis in stably transformed tomato plants. All 14 genes were suppressed by RNA interference (RNAi) using a constitutive promoter, and 5 of them were also suppressed using an abscission-specific promoter. Transformations are currently at different stages of progress including some lines that already display an abscission phenotype. Objectives: We propose here to (1) complete the functional analysis of the stably transformed tomato plants with T2 lines and perform transcriptome analysis using custom abscission-specific microarrays; (2) conduct an indepth analysis of the role of IDA signaling in tomato leaf and flower abscission; (3) perform transcriptome and proteome analyses to extend the earlier gene expression studies to identify transcripts and proteins that are highly specific to the separation layer (i.e., target cells for cell separation) prior to the onset of abscission; (4) extend and compliment the work in tomato using a winnowed set of genes in soybean. Methodology: Next Generation Sequencing (NGS) of mRNA will be used to further increase the list of abscission-associated genes, and for preparation of a custom tomato abscission microarray to test altered gene expression in transgenic plants. Tandem mass spectrometry (LC-MS/MS) of protein extracts from leaf petiole, flower pedicel and their AZ tissues will be used to identify the proteome of the AZ before and during abscission. AZ-specific gene promoters will be used in stably transformed tomato plants to reduce non-target phenotypes. The bean pod mottle virus (BPMV) plasmid vectors will be used for VIGS analysis in soybean. Expected Contribution: Our study will provide new insights into the regulation of ethylene-induced abscission by further revealing the role of key regulators in the process. This will permit development of novel techniques for manipulating leaf and flower abscission, thereby improving the postharvest performance of agriculturally important crops.
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Oliynyk, Kateryna, and Matteo Ciantia. Application of a finite deformation multiplicative plasticity model with non-local hardening to the simulation of CPTu tests in a structured soil. University of Dundee, December 2021. http://dx.doi.org/10.20933/100001230.

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In this paper an isotropic hardening elastoplastic constitutive model for structured soils is applied to the simulation of a standard CPTu test in a saturated soft structured clay. To allow for the extreme deformations experienced by the soil during the penetration process, the model is formulated in a fully geometric non-linear setting, based on: i) the multiplicative decomposition of the deformation gradient into an elastic and a plastic part; and, ii) on the existence of a free energy function to define the elastic behaviour of the soil. The model is equipped with two bonding-related internal variables which provide a macroscopic description of the effects of clay structure. Suitable hardening laws are employed to describe the structure degradation associated to plastic deformations. The strain-softening associated to bond degradation usually leads to strain localization and consequent formation of shear bands, whose thickness is dependent on the characteristics of the microstructure (e.g, the average grain size). Standard local constitutive models are incapable of correctly capturing this phenomenon due to the lack of an internal length scale. To overcome this limitation, the model is framed using a non-local approach by adopting volume averaged values for the internal state variables. The size of the neighbourhood over which the averaging is performed (characteristic length) is a material constant related to the microstructure which controls the shear band thickness. This extension of the model has proven effective in regularizing the pathological mesh dependence of classical finite element solutions in the post-localization regime. The results of numerical simulations, conducted for different soil permeabilities and bond strengths, show that the model captures the development of plastic deformations induced by the advancement of the cone tip; the destructuration of the clay associated with such plastic deformations; the space and time evolution of pore water pressure as the cone tip advances. The possibility of modelling the CPTu tests in a rational and computationally efficient way opens a promising new perspective for their interpretation in geotechnical site investigations.
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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.

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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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Wilson, Thomas E., Avraham A. Levy, and Tzvi Tzfira. Controlling Early Stages of DNA Repair for Gene-targeting Enhancement in Plants. United States Department of Agriculture, March 2012. http://dx.doi.org/10.32747/2012.7697124.bard.

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Gene targeting (GT) is a much needed technology as a tool for plant research and for the precise engineering of crop species. Recent advances in this field have shown that the presence of a DNA double-strand break (DSB) in a genomic locus is critical for the integration of an exogenous DNA molecule introduced into this locus. This integration can occur via either non-homologous end joining (NHEJ) into the break or homologous recombination (HR) between the broken genomic DNA and the introduced vector. A bottleneck for DNA integration via HR is the machinery responsible for homology search and strand invasion. Important proteins in this pathway are Rad51, Rad52 and Rad54. We proposed to combine our respective expertise: on the US side, in the design of zincfinger nucleases (ZFNs) for the induction of DNA DSBs at any desired genomic locus and in the integration of DNA molecules via NHEJ; and on the Israeli side in the HR events, downstream of the DSB, that lead to homology search and strand invasion. We sought to test three major pathways of targeted DNA integration: (i) integration by NHEJ into DSBs induced at desired sites by specially designed ZFNs; (ii) integration into DSBs induced at desired sites combined with the use of Rad51, Rad52 and Rad54 proteins to maximize the chances for efficient and precise HR-mediated vector insertion; (iii) stimulation of HR by Rad51, Rad52 and Rad54 in the absence of DSB induction. We also proposed to study the formation of dsT-DNA molecules during the transformation of plant cells. dsT-DNA molecules are an important substrate for HR and NHEJ-mediatedGT, yet the mode of their formation from single stranded T-DNA molecules is still obscure. In addition we sought to develop a system for assembly of multi-transgene binary vectors by using ZFNs. The latter may facilitate the production of binary vectors that may be ready for genome editing in transgenic plants. ZFNs were proposed for the induction of DSBs in genomic targets, namely, the FtsH2 gene whose loss of function can easily be identified in somatic tissues as white sectors, and the Cruciferin locus whose targeting by a GFP or RFP reporter vectors can give rise to fluorescent seeds. ZFNs were also proposed for the induction of DSBs in artificial targets and for assembly of multi-gene vectors. We finally sought to address two important cell types in terms of relevance to plant transformation, namely GT of germinal (egg) cells by floral dipping, and GT in somatic cells by root and leave transformation. To be successful, we made use of novel optimized expression cassettes that enable coexpression of all of the genes of interest (ZFNs and Rad genes) in the right tissues (egg or root cells) at the right time, namely when the GT vector is delivered into the cells. Methods were proposed for investigating the complementation of T-strands to dsDNA molecules in living plant cells. During the course of this research, we (i) designed, assembled and tested, in vitro, a pair of new ZFNs capable of targeting the Cruciferin gene, (ii) produced transgenic plants which expresses for ZFN monomers for targeting of the FtsH2 gene. Expression of these enzymes is controlled by constitutive or heat shock induced promoters, (iii) produced a large population of transgenic Arabidopsis lines in which mutated mGUS gene was incorporated into different genomic locations, (iv) designed a system for egg-cell-specific expression of ZFNs and RAD genes and initiate GT experiments, (v) demonstrated that we can achieve NHEJ-mediated gene replacement in plant cells (vi) developed a system for ZFN and homing endonuclease-mediated assembly of multigene plant transformation vectors and (vii) explored the mechanism of dsTDNA formation in plant cells. This work has substantially advanced our understanding of the mechanisms of DNA integration into plants and furthered the development of important new tools for GT in plants.
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Epel, Bernard L., Roger N. Beachy, A. Katz, G. Kotlinzky, M. Erlanger, A. Yahalom, M. Erlanger, and J. Szecsi. Isolation and Characterization of Plasmodesmata Components by Association with Tobacco Mosaic Virus Movement Proteins Fused with the Green Fluorescent Protein from Aequorea victoria. United States Department of Agriculture, September 1999. http://dx.doi.org/10.32747/1999.7573996.bard.

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The coordination and regulation of growth and development in multicellular organisms is dependent, in part, on the controlled short and long-distance transport of signaling molecule: In plants, symplastic communication is provided by trans-wall co-axial membranous tunnels termed plasmodesmata (Pd). Plant viruses spread cell-to-cell by altering Pd. This movement scenario necessitates a targeting mechanism that delivers the virus to a Pd and a transport mechanism to move the virion or viral nucleic acid through the Pd channel. The identity of host proteins with which MP interacts, the mechanism of the targeting of the MP to the Pd and biochemical information on how Pd are alter are questions which have been dealt with during this BARD project. The research objectives of the two labs were to continue their biochemical, cellular and molecular studies of Pd composition and function by employing infectious modified clones of TMV in which MP is fused with GFP. We examined Pd composition, and studied the intra- and intercellular targeting mechanism of MP during the infection cycle. Most of the goals we set for ourselves were met. The Israeli PI and collaborators (Oparka et al., 1999) demonstrated that Pd permeability is under developmental control, that Pd in sink tissues indiscriminately traffic proteins of sizes of up to 50 kDa and that during the sink to source transition there is a substantial decrease in Pd permeability. It was shown that companion cells in source phloem tissue export proteins which traffic in phloem and which unload in sink tissue and move cell to cell. The TAU group employing MP:GFP as a fluorescence probe for optimized the procedure for Pd isolation. At least two proteins kinases found to be associated with Pd isolated from source leaves of N. benthamiana, one being a calcium dependent protein kinase. A number of proteins were microsequenced and identified. Polyclonal antibodies were generated against proteins in a purified Pd fraction. A T-7 phage display library was created and used to "biopan" for Pd genes using these antibodies. Selected isolates are being sequenced. The TAU group also examined whether the subcellular targeting of MP:GFP was dependent on processes that occurred only in the presence of the virus or whether targeting was a property indigenous to MP. Mutant non-functional movement proteins were also employed to study partial reactions. Subcellular targeting and movement were shown to be properties indigenous to MP and that these processes do not require other viral elements. The data also suggest post-translational modification of MP is required before the MP can move cell to cell. The USA group monitored the development of the infection and local movement of TMV in N. benthamiana, using viral constructs expressing GFP either fused to the MP of TMV or expressing GFP as a free protein. The fusion protein and/or the free GFP were expressed from either the movement protein subgenomic promoter or from the subgenomic promoter of the coat protein. Observations supported the hypothesis that expression from the cp sgp is regulated differently than expression from the mp sgp (Szecsi et al., 1999). Using immunocytochemistry and electron microscopy, it was determined that paired wall-appressed bodies behind the leading edge of the fluorescent ring induced by TMV-(mp)-MP:GFP contain MP:GFP and the viral replicase. These data suggest that viral spread may be a consequence of the replication process. Observation point out that expression of proteins from the mp sgp is temporary regulated, and degradation of the proteins occurs rapidly or more slowly, depending on protein stability. It is suggested that the MP contains an external degradation signal that contributes to rapid degradation of the protein even if expressed from the constitutive cp sgp. Experiments conducted to determine whether the degradation of GFP and MP:GFP was regulated at the protein or RNA level, indicated that regulation was at the protein level. RNA accumulation in infected protoplast was not always in correlation with protein accumulation, indicating that other mechanisms together with RNA production determine the final intensity and stability of the fluorescent proteins.
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