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Sample records for fusion-mediated plant immunity

  1. Plant Immunity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plants are faced with defending themselves against a multitude of pathogens, including bacteria, fungi, viruses, nematodes, etc. Immunity is multi-layered and complex. Plants can induce defenses when they recognize small peptides, proteins or double-stranded RNA associated with pathogens. Recognitio...

  2. Plant Innate Immunity Multicomponent Model.

    PubMed

    Andolfo, Giuseppe; Ercolano, Maria R

    2015-01-01

    Our understanding of plant-pathogen interactions is making rapid advances in order to address issues of global importance such as improving agricultural productivity and sustainable food security. Innate immunity has evolved in plants, resulting in a wide diversity of defense mechanisms adapted to specific threats. The postulated PTI/ETI model describes two perception layers of plant innate immune system, which belong to a first immunity component of defense response activation. To better describe the sophisticated defense system of plants, we propose a new model of plant immunity. This model considers the plant's ability to distinguish the feeding behavior of their many foes, such as a second component that modulates innate immunity. This hypothesis provides a new viewpoint highlighting the relevance of hormone crosstalk and primary metabolism in regulating plant defense against the different behaviors of pathogens with the intention to stimulate further interest in this research area. PMID:26617626

  3. Plant Innate Immunity Multicomponent Model.

    PubMed

    Andolfo, Giuseppe; Ercolano, Maria R

    2015-01-01

    Our understanding of plant-pathogen interactions is making rapid advances in order to address issues of global importance such as improving agricultural productivity and sustainable food security. Innate immunity has evolved in plants, resulting in a wide diversity of defense mechanisms adapted to specific threats. The postulated PTI/ETI model describes two perception layers of plant innate immune system, which belong to a first immunity component of defense response activation. To better describe the sophisticated defense system of plants, we propose a new model of plant immunity. This model considers the plant's ability to distinguish the feeding behavior of their many foes, such as a second component that modulates innate immunity. This hypothesis provides a new viewpoint highlighting the relevance of hormone crosstalk and primary metabolism in regulating plant defense against the different behaviors of pathogens with the intention to stimulate further interest in this research area.

  4. Immunity: plants as effective mediators.

    PubMed

    Sultan, M Tauseef; Butt, Masood Sadiq; Qayyum, Mir M Nasir; Suleria, Hafiz Ansar Rasul

    2014-01-01

    In the domain of nutrition, exploring the diet-health linkages is major area of research. The outcomes of such interventions led to widespread acceptance of functional and nutraceutical foods; however, augmenting immunity is a major concern of dietary regimens. Indeed, the immune system is incredible arrangement of specific organs and cells that enabled humans to carry out defense against undesired responses. Its proper functionality is essential to maintain the body homeostasis. Array of plants and their components hold immunomodulating properties. Their possible inclusion in diets could explore new therapeutic avenues to enhanced immunity against diseases. The review intended to highlight the importance of garlic (Allium sativum), green tea (Camellia sinensis), ginger (Zingiber officinale), purple coneflower (Echinacea), black cumin (Nigella sativa), licorice (Glycyrrhiza glabra), Astragalus and St. John's wort (Hypericum perforatum) as natural immune boosters. These plants are bestowed with functional ingredients that may provide protection against various menaces. Modes of their actions include boosting and functioning of immune system, activation and suppression of immune specialized cells, interfering in several pathways that eventually led to improvement in immune responses and defense system. In addition, some of these plants carry free radical scavenging and anti-inflammatory activities that are helpful against cancer insurgence. Nevertheless, interaction between drugs and herbs/botanicals should be well investigated before recommended for their safe use, and such information must be disseminated to the allied stakeholders.

  5. Priming in Systemic Plant Immunity

    SciTech Connect

    Jung, Ho Won; Tschaplinski, Timothy J; Wang, Lin; Glazebrook, Jane; Greenberg, Jean T.

    2009-01-01

    Upon local infection, plants possess inducible systemic defense responses against their natural enemies. Bacterial infection results in the accumulation to high levels of the mobile metabolite C9-dicarboxylic acid azelaic acid in the vascular sap of Arabidopsis. Azelaic acid confers local and systemic resistance against Pseudomonas syringae. The compound primes plants to strongly accumulate salicylic acid (SA), a known defense signal, upon infection. Mutation of a gene induced by azelaic acid (AZI1) results in the specific loss in plants of systemic immunity triggered by pathogen or azelaic acid and of the priming of SA induction. AZI1, a predicted secreted protein, is also important for generating vascular sap that confers disease resistance. Thus, azelaic acid and AZI1 comprise novel components of plant systemic immunity involved in priming defenses.

  6. Transcriptional networks in plant immunity.

    PubMed

    Tsuda, Kenichi; Somssich, Imre E

    2015-05-01

    Next to numerous abiotic stresses, plants are constantly exposed to a variety of pathogens within their environment. Thus, their ability to survive and prosper during the course of evolution was strongly dependent on adapting efficient strategies to perceive and to respond to such potential threats. It is therefore not surprising that modern plants have a highly sophisticated immune repertoire consisting of diverse signal perception and intracellular signaling pathways. This signaling network is intricate and deeply interconnected, probably reflecting the diverse lifestyles and infection strategies used by the multitude of invading phytopathogens. Moreover it allows signal communication between developmental and defense programs thereby ensuring that plant growth and fitness are not significantly retarded. How plants integrate and prioritize the incoming signals and how this information is transduced to enable appropriate immune responses is currently a major research area. An important finding has been that pathogen-triggered cellular responses involve massive transcriptional reprogramming within the host. Additional key observations emerging from such studies are that transcription factors (TFs) are often sites of signal convergence and that signal-regulated TFs act in concert with other context-specific TFs and transcriptional co-regulators to establish sensory transcription regulatory networks required for plant immunity.

  7. Alternative Splicing in Plant Immunity

    PubMed Central

    Yang, Shengming; Tang, Fang; Zhu, Hongyan

    2014-01-01

    Alternative splicing (AS) occurs widely in plants and can provide the main source of transcriptome and proteome diversity in an organism. AS functions in a range of physiological processes, including plant disease resistance, but its biological roles and functional mechanisms remain poorly understood. Many plant disease resistance (R) genes undergo AS, and several R genes require alternatively spliced transcripts to produce R proteins that can specifically recognize pathogen invasion. In the finely-tuned process of R protein activation, the truncated isoforms generated by AS may participate in plant disease resistance either by suppressing the negative regulation of initiation of immunity, or by directly engaging in effector-triggered signaling. Although emerging research has shown the functional significance of AS in plant biotic stress responses, many aspects of this topic remain to be understood. Several interesting issues surrounding the AS of R genes, especially regarding its functional roles and regulation, will require innovative techniques and additional research to unravel. PMID:24918296

  8. JASMONATE-TRIGGERED PLANT IMMUNITY

    PubMed Central

    Campos, Marcelo L.; Kang, Jin-Ho; Howe, Gregg A.

    2014-01-01

    The plant hormone jasmonate (JA) exerts direct control over the production of chemical defense compounds that confer resistance to a remarkable spectrum of plant-associated organisms, ranging from microbial pathogens to vertebrate herbivores. The underlying mechanism of JA-triggered immunity (JATI) can be conceptualized as a multi-stage signal transduction cascade involving: i) pattern recognition receptors (PRRs) that couple the perception of danger signals to rapid synthesis of bioactive JA; ii) an evolutionarily conserved JA signaling module that links fluctuating JA levels to changes in the abundance of transcriptional repressor proteins; and iii) activation (de-repression) of transcription factors that orchestrate the expression of myriad chemical and morphological defense traits. Multiple negative feedback loops act in concert to restrain the duration and amplitude of defense responses, presumably to mitigate potential fitness costs of JATI. The convergence of diverse plant- and non-plant-derived signals on the core JA module indicates that JATI is a general response to perceived danger. However, the modular structure of JATI may accommodate attacker-specific defense responses through evolutionary innovation of PRRs (inputs) and defense traits (outputs). The efficacy of JATI as a defense strategy is highlighted by its capacity to shape natural populations of plant attackers, as well as the propensity of plant-associated organisms to subvert or otherwise manipulate JA signaling. As both a cellular hub for integrating informational cues from the environment and a common target of pathogen effectors, the core JA module provides a focal point for understanding immune system networks and the evolution of chemical diversity in the plant kingdom. PMID:24973116

  9. Transcription Dynamics in Plant Immunity

    PubMed Central

    Moore, John W.; Loake, Gary J.; Spoel, Steven H.

    2011-01-01

    Plant cells maintain sophisticated gene transcription programs to regulate their development, communication, and response to the environment. Environmental stress cues, such as pathogen encounter, lead to dramatic reprogramming of transcription to favor stress responses over normal cellular functions. Transcription reprogramming is conferred by the concerted action of myriad transcription (co)factors that function directly or indirectly to recruit or release RNA Polymerase II. To establish an effective defense response, cells require transcription (co)factors to deploy their activity rapidly, transiently, spatially, and hierarchically. Recent findings suggest that in plant immunity these requirements are met by posttranslational modifications that accurately regulate transcription (co)factor activity as well as by sequential pulse activation of specific gene transcription programs that provide feedback and feedforward properties to the defense gene network. Here, we integrate these recent findings from plant defense studies into the emerging field of transcription dynamics in eukaryotes. PMID:21841124

  10. Ubiquitination of plant immune receptors.

    PubMed

    Zhou, Jinggeng; He, Ping; Shan, Libo

    2014-01-01

    Ubiquitin is a highly conserved regulatory protein consisting of 76 amino acids and ubiquitously expressed in all eukaryotic cells. The reversible ubiquitin conjugation to a wide variety of target proteins, a process known as ubiquitination or ubiquitylation, serves as one of the most important and prevalent posttranslational modifications to regulate the myriad actions of protein cellular functions, including protein degradation, vesicle trafficking, and subcellular localization. Protein ubiquitination is an ATP-dependent stepwise covalent attachment of one or more ubiquitin molecules to target proteins mediated by a hierarchical enzymatic cascade consisting of an E1 ubiquitin-activating enzyme, E2 ubiquitin-conjugating enzyme, and E3 ubiquitin ligase. The plant plasma membrane resident receptor-like kinase Flagellin Sensing 2 (FLS2) recognizes bacterial flagellin and initiates innate immune signaling to defend against pathogen attacks. We have recently shown that two plant U-box E3 ubiquitin ligases PUB12 and PUB13 directly ubiquitinate FLS2 and promote flagellin-induced FLS2 degradation, which in turn attenuates FLS2 signaling to prevent excessive or prolonged activation of immune responses. Here, we use FLS2 as an example to describe a protocol for detection of protein ubiquitination in plant cells in vivo and in test tubes in vitro. In addition, we elaborate the approach to identify different types of ubiquitin linkages by using various lysine mutants of ubiquitin. The various in vivo and in vitro ubiquitination assays will provide researchers with the tools to address how ubiquitination regulates diverse cellular functions of target proteins. PMID:25117287

  11. Plant Immune Responses: Aphids Strike Back.

    PubMed

    Reymond, Philippe; Calandra, Thierry

    2015-07-20

    To survive and complete their life cycle, herbivorous insects face the difficult challenge of coping with the arsenal of plant defences. A new study reports that aphids secrete evolutionarily conserved cytokines in their saliva to suppress host immune responses.

  12. Protein trafficking during plant innate immunity.

    PubMed

    Wang, Wen-Ming; Liu, Peng-Qiang; Xu, Yong-Ju; Xiao, Shunyuan

    2016-04-01

    Plants have evolved a sophisticated immune system to fight against pathogenic microbes. Upon detection of pathogen invasion by immune receptors, the immune system is turned on, resulting in production of antimicrobial molecules including pathogenesis-related (PR) proteins. Conceivably, an efficient immune response depends on the capacity of the plant cell's protein/membrane trafficking network to deploy the right defense-associated molecules in the right place at the right time. Recent research in this area shows that while the abundance of cell surface immune receptors is regulated by endocytosis, many intracellular immune receptors, when activated, are partitioned between the cytoplasm and the nucleus for induction of defense genes and activation of programmed cell death, respectively. Vesicle transport is an essential process for secretion of PR proteins to the apoplastic space and targeting of defense-related proteins to the plasma membrane or other endomembrane compartments. In this review, we discuss the various aspects of protein trafficking during plant immunity, with a focus on the immunity proteins on the move and the major components of the trafficking machineries engaged. PMID:26345282

  13. Plant innate immunity – sunny side up?

    PubMed Central

    Stael, Simon; Kmiecik, Przemyslaw; Willems, Patrick; Van Der Kelen, Katrien; Coll, Nuria S.; Teige, Markus; Van Breusegem, Frank

    2016-01-01

    Reactive oxygen species (ROS)- and calcium- dependent signaling pathways play well-established roles during plant innate immunity. Chloroplasts host major biosynthetic pathways and have central roles in energy production, redox homeostasis, and retrograde signaling. However, the organelle’s importance in immunity has been somehow overlooked. Recent findings suggest that the chloroplast also has an unanticipated function as a hub for ROS- and calcium-signaling that affects immunity responses at an early stage after pathogen attack. In this opinion article, we discuss a chloroplastic calcium-ROS signaling branch of plant innate immunity. We propose that this chloroplastic branch acts as a light-dependent rheostat that, through the production of ROS, influences the severity of the immune response. PMID:25457110

  14. Diuretics Prime Plant Immunity in Arabidopsis thaliana

    PubMed Central

    Noutoshi, Yoshiteru; Ikeda, Mika; Shirasu, Ken

    2012-01-01

    Plant activators are agrochemicals that activate the plant immune system, thereby enhancing disease resistance. Due to their prophylactic and durable effects on a wide spectrum of diseases, plant activators can provide synergistic crop protection when used in combination with traditional pest controls. Although plant activators have achieved great success in wet-rice farming practices in Asia, their use is still limited. To isolate novel plant activators applicable to other crops, we screened a chemical library using a method that can selectively identify immune-priming compounds. Here, we report the isolation and characterization of three diuretics, bumetanide, bendroflumethiazide and clopamide, as immune-priming compounds. These drugs upregulate the immunity-related cell death of Arabidopsis suspension-cultured cells induced with an avirulent strain of Pseudomonas syringae pv. tomato in a concentration-dependent manner. The application of these compounds to Arabidopsis plants confers disease resistance to not only the avirulent but also a virulent strain of the pathogen. Unlike salicylic acid, an endogenous phytohormone that governs disease resistance in response to biotrophic pathogens, the three diuretic compounds analyzed here do not induce PR1 or inhibit plant growth, showing potential as lead compounds in a practical application. PMID:23144763

  15. Vesicle trafficking in plant immune responses.

    PubMed

    Robatzek, Silke

    2007-01-01

    In plants, perception of pathogen-associated molecular patterns at the surface is the first line of defence in cellular immunity. This review summarizes recent evidence of the involvement of vesicle trafficking in the plant's immune response against pathogens. I first discuss aspects of ligand-stimulated receptor endocytosis. The best-characterized pattern-recognition receptor (PRR), FLS2, is a transmembrane leucine-rich repeat receptor kinase that recognizes bacterial flagellin. FLS2 was recently shown to undergo internalization upon activation with its cognate ligand. An animal PRR, TLR4 that mediates perception of bacterial-derived lipopolysaccharides, similarly exhibits ligand-stimulated endocytosis. The second focus is N-ethylmaleimide-sensitive factor adaptor protein receptor (SNARE)-mediated immunity involving syntaxins and their cognate partners. One of the genes involved in basal immunity in Arabidopsis, PEN1, encodes a syntaxin that focally accumulates at fungal penetration sites, raising the possibility that induced exocytosis is important for active defence. Pathogen-triggered endocytic and exocytic processes have to be balanced to ensure host cell homeostasis. Thus, understanding how phytopathogens have evolved strategies to exploit host cell vesicle trafficking to manipulate immune responses is currently an area of intense study. PMID:17081192

  16. Ready to fire: Secretion in plant immunity.

    PubMed

    Sup Yun, Hye; Panstruga, Ralph; Schulze-Lefert, Paul; Kwon, Chian

    2008-07-01

    Effective recognition of pathogens and rapid execution of immune responses are essential for the survival of living organisms. Cell-autonomous immune responses of animal and plant cells rely on pattern recognition receptors that can distinguish self from non-self structures and that are able to activate a molecular execution machinery that ultimately terminates most pathogen attacks. Reminiscent of the situation in mammalian T cells, accumulating evidence points to a key role of vesicle trafficking and exocytosis in plant innate immunity. In this context, our recent finding that ternary soluble N-ethylmaleimide sensitive factor attachment protein receptor (SNARE) complexes comprising PEN1, SNAP33 and VAMP721/722 function at pathogen entry sites is instrumental in understanding the execution of plant immune responses at the cell periphery. Our study further revealed unexpected overlapping functions of the same SNARE complexes in disease resistance and development. Here, we discuss the potential identity of cargo delivered through the PEN1-SNAP33-VAMP721/722-dependent secretory pathway and the necessity for a tight regulation of SNARE complex formation to avoid unintentional release of toxic load. PMID:19704501

  17. Immunity to plant pathogens and iron homeostasis.

    PubMed

    Aznar, Aude; Chen, Nicolas W G; Thomine, Sebastien; Dellagi, Alia

    2015-11-01

    Iron is essential for metabolic processes in most living organisms. Pathogens and their hosts often compete for the acquisition of this nutrient. However, iron can catalyze the formation of deleterious reactive oxygen species. Hosts may use iron to increase local oxidative stress in defense responses against pathogens. Due to this duality, iron plays a complex role in plant-pathogen interactions. Plant defenses against pathogens and plant response to iron deficiency share several features, such as secretion of phenolic compounds, and use common hormone signaling pathways. Moreover, fine tuning of iron localization during infection involves genes coding iron transport and iron storage proteins, which have been shown to contribute to immunity. The influence of the plant iron status on the outcome of a given pathogen attack is strongly dependent on the nature of the pathogen infection strategy and on the host species. Microbial siderophores emerged as important factors as they have the ability to trigger plant defense responses. Depending on the plant species, siderophore perception can be mediated by their strong iron scavenging capacity or possibly via specific recognition as pathogen associated molecular patterns. This review highlights that iron has a key role in several plant-pathogen interactions by modulating immunity. PMID:26475190

  18. Regulation of plant immune receptors by ubiquitination.

    PubMed

    Furlan, Giulia; Klinkenberg, Jörn; Trujillo, Marco

    2012-01-01

    From pathogen perception and the activation of signal transduction cascades to the deployment of defense responses, protein ubiquitination plays a key role in the modulation of plant immunity. Ubiquitination is mediated by three enzymes, of which the E3 ubiquitin ligases, the substrate determinants, have been the major focus of attention. Accumulating evidence suggests that ubiquitination modulates signaling mediated by pattern recognition receptors and is important for the accumulation of nucleotide-binding leucine-rich repeat type intracellular immune sensors. Recent studies also indicate that ubiquitination directs vesicle trafficking, a function that has been clearly established for immune signaling in animals. In this mini review, we discuss these and other recent advances and highlight important open questions. PMID:23109936

  19. Plant immunity in plant–aphid interactions

    PubMed Central

    Jaouannet, Maëlle; Rodriguez, Patricia A.; Lenoir, Camille J. G.; MacLeod, Ruari; Escudero-Martinez, Carmen; Bos, Jorunn I.B.

    2014-01-01

    Aphids are economically important pests that cause extensive feeding damage and transmit viruses. While some species have a broad host range and cause damage to a variety of crops, others are restricted to only closely related plant species. While probing and feeding aphids secrete saliva, containing effectors, into their hosts to manipulate host cell processes and promote infestation. Aphid effector discovery studies pointed out parallels between infection and infestation strategies of plant pathogens and aphids. Interestingly, resistance to some aphid species is known to involve plant resistance proteins with a typical NB-LRR domain structure. Whether these resistance proteins indeed recognize aphid effectors to trigger ETI remains to be elucidated. In addition, it was recently shown that unknown aphid derived elicitors can initiate reactive oxygen species (ROS) production and callose deposition and that these responses were dependent on BAK1 (BRASSINOSTERIOD INSENSITIVE 1-ASSOCIATED RECEPTOR KINASE 1) which is a key component of the plant immune system. In addition, BAK-1 contributes to non-host resistance to aphids pointing to another parallel between plant-pathogen and – aphid interactions. Understanding the role of plant immunity and non-host resistance to aphids is essential to generate durable and sustainable aphid control strategies. Although insect behavior plays a role in host selection and non-host resistance, an important observation is that aphids interact with non-host plants by probing the leaf surface, but are unable to feed or establish colonization. Therefore, we hypothesize that aphids interact with non-host plants at the molecular level, but are potentially not successful in suppressing plant defenses and/or releasing nutrients. PMID:25520727

  20. Mediated plastid RNA editing in plant immunity.

    PubMed

    García-Andrade, Javier; Ramírez, Vicente; López, Ana; Vera, Pablo

    2013-10-01

    Plant regulatory circuits coordinating nuclear and plastid gene expression have evolved in response to external stimuli. RNA editing is one of such control mechanisms. We determined the Arabidopsis nuclear-encoded homeodomain-containing protein OCP3 is incorporated into the chloroplast, and contributes to control over the extent of ndhB transcript editing. ndhB encodes the B subunit of the chloroplast NADH dehydrogenase-like complex (NDH) involved in cyclic electron flow (CEF) around photosystem I. In ocp3 mutant strains, ndhB editing efficiency decays, CEF is impaired and disease resistance to fungal pathogens substantially enhanced, a process recapitulated in plants defective in editing plastid RNAs encoding NDH complex subunits due to mutations in previously described nuclear-encoded pentatricopeptide-related proteins (i.e. CRR21, CRR2). Furthermore, we observed that following a pathogenic challenge, wild type plants respond with editing inhibition of ndhB transcript. In parallel, rapid destabilization of the plastidial NDH complex is also observed in the plant following perception of a pathogenic cue. Therefore, NDH complex activity and plant immunity appear as interlinked processes.

  1. Recognition of bacterial plant pathogens: local, systemic and transgenerational immunity.

    PubMed

    Henry, Elizabeth; Yadeta, Koste A; Coaker, Gitta

    2013-09-01

    Bacterial pathogens can cause multiple plant diseases and plants rely on their innate immune system to recognize and actively respond to these microbes. The plant innate immune system comprises extracellular pattern recognition receptors that recognize conserved microbial patterns and intracellular nucleotide binding leucine-rich repeat (NLR) proteins that recognize specific bacterial effectors delivered into host cells. Plants lack the adaptive immune branch present in animals, but still afford flexibility to pathogen attack through systemic and transgenerational resistance. Here, we focus on current research in plant immune responses against bacterial pathogens. Recent studies shed light onto the activation and inactivation of pattern recognition receptors and systemic acquired resistance. New research has also uncovered additional layers of complexity surrounding NLR immune receptor activation, cooperation and sub-cellular localizations. Taken together, these recent advances bring us closer to understanding the web of molecular interactions responsible for coordinating defense responses and ultimately resistance.

  2. [Nitric oxide is a major player in plant immune system].

    PubMed

    Koen, Emmanuel; Lamotte, Olivier; Besson-Bard, Angélique; Bourque, Stéphane; Nicolas-Francès, Valérie; Jeandroz, Sylvain; Wendehenne, David

    2013-03-01

    In animals, nitric oxide (NO) functions as a ubiquitous signaling molecule involved in diverse physiological processes such as immunity. Recent studies provided evidence that plants challenged by pathogenic microorganisms also produce NO. The emerging picture is that NO functions as a signal in plant immunity and executes part of its effects through posttranslational protein modifications. Notably, the characterization of S-nitrosylated proteins provided insights into the molecular mechanisms by which NO exerts its activities. Based on these findings, it appears that NO is involved in both the activation and the negative control of the signaling pathways related to plant immunity. PMID:23544386

  3. Roles of plant hormones and their interplay in rice immunity.

    PubMed

    Yang, Dong-Lei; Yang, Yinong; He, Zuhua

    2013-05-01

    Plant hormones have been extensively studied for their importance in innate immunity particularly in the dicotyledonous model plant Arabidopsis thaliana. However, only in the last decade, plant hormones were demonstrated to play conserved and divergent roles in fine-tuning immune in rice (Oryza sativa L.), a monocotyledonous model crop plant. Emerging evidence showed that salicylic acid (SA) plays a role in rice basal defense but is differentially required by rice pattern recognition receptor (PRR) and resistance (R) protein-mediated immunity, and its function is likely dependent on the signaling pathway rather than the change of endogenous levels. Jasmonate (JA) plays an important role in rice basal defense against bacterial and fungal infection and may be involved in the SA-mediated resistance. Ethylene (ET) can act as a positive or negative modulator of disease resistance, depending on the pathogen type and environmental conditions. Brassinosteroid (BR) signaling and abscisic acid (ABA) either promote or defend against infection of pathogens with distinct infection/colonization strategies. Auxin and gibberellin (GA) are generally thought of as negative regulators of innate immunity in rice. Moreover, GA interacts antagonistically with JA signaling in rice development and immunity through the DELLA protein as a master regulator of the two hormone pathways. In this review, we summarize the roles of plant hormones in rice immunity and discuss their interplay/crosstalk mechanisms and the complex regulatory network of plant hormone pathways in fine-tuning rice immunity and growth.

  4. Express yourself: Transcriptional regulation of plant innate immunity.

    PubMed

    Garner, Christopher M; Kim, Sang Hee; Spears, Benjamin J; Gassmann, Walter

    2016-08-01

    The plant immune system is a complex network of components that function together to sense the presence and activity of potential biotic threats, and integrate these signals into an appropriate output, namely the transcription of genes that activate an immune response that is commensurate with the perceived threat. Given the variety of biotic threats a plant must face the immune response must be plastic, but because an immune response is costly to the plant in terms of energy expenditure and development it must also be under tight control. To meet these needs transcriptional control is exercised at multiple levels. In this article we will review some of the latest developments in understanding how the plant immune response is regulated at the level of transcription. New roles are being discovered for the long-studied WRKY and TGA transcription factor families, while additional critical defense functions are being attributed to TCPs and other transcription factors. Dynamically controlling access to DNA through post-translational modification of histones is emerging as an essential component of priming, maintaining, attenuating, and repressing transcription in response to biotic stress. Unsurprisingly, the plant's transcriptional response is targeted by pathogen effectors, and in turn resistance proteins stand guard over and participate in transcriptional regulation. Together, these multiple layers lead to the observed complexity of the plant transcriptional immune response, with different transcription factors or chromatin components playing a prominent role depending on the plant-pathogen interaction being studied. PMID:27174437

  5. Express yourself: Transcriptional regulation of plant innate immunity.

    PubMed

    Garner, Christopher M; Kim, Sang Hee; Spears, Benjamin J; Gassmann, Walter

    2016-08-01

    The plant immune system is a complex network of components that function together to sense the presence and activity of potential biotic threats, and integrate these signals into an appropriate output, namely the transcription of genes that activate an immune response that is commensurate with the perceived threat. Given the variety of biotic threats a plant must face the immune response must be plastic, but because an immune response is costly to the plant in terms of energy expenditure and development it must also be under tight control. To meet these needs transcriptional control is exercised at multiple levels. In this article we will review some of the latest developments in understanding how the plant immune response is regulated at the level of transcription. New roles are being discovered for the long-studied WRKY and TGA transcription factor families, while additional critical defense functions are being attributed to TCPs and other transcription factors. Dynamically controlling access to DNA through post-translational modification of histones is emerging as an essential component of priming, maintaining, attenuating, and repressing transcription in response to biotic stress. Unsurprisingly, the plant's transcriptional response is targeted by pathogen effectors, and in turn resistance proteins stand guard over and participate in transcriptional regulation. Together, these multiple layers lead to the observed complexity of the plant transcriptional immune response, with different transcription factors or chromatin components playing a prominent role depending on the plant-pathogen interaction being studied.

  6. Programmed cell death in the plant immune system

    PubMed Central

    Coll, N S; Epple, P; Dangl, J L

    2011-01-01

    Cell death has a central role in innate immune responses in both plants and animals. Besides sharing striking convergences and similarities in the overall evolutionary organization of their innate immune systems, both plants and animals can respond to infection and pathogen recognition with programmed cell death. The fact that plant and animal pathogens have evolved strategies to subvert specific cell death modalities emphasizes the essential role of cell death during immune responses. The hypersensitive response (HR) cell death in plants displays morphological features, molecular architectures and mechanisms reminiscent of different inflammatory cell death types in animals (pyroptosis and necroptosis). In this review, we describe the molecular pathways leading to cell death during innate immune responses. Additionally, we present recently discovered caspase and caspase-like networks regulating cell death that have revealed fascinating analogies between cell death control across both kingdoms. PMID:21475301

  7. MAMP (microbe-associated molecular pattern) triggered immunity in plants

    PubMed Central

    Newman, Mari-Anne; Sundelin, Thomas; Nielsen, Jon T.; Erbs, Gitte

    2013-01-01

    Plants are sessile organisms that are under constant attack from microbes. They rely on both preformed defenses, and their innate immune system to ward of the microbial pathogens. Preformed defences include for example the cell wall and cuticle, which act as physical barriers to microbial colonization. The plant immune system is composed of surveillance systems that perceive several general microbe elicitors, which allow plants to switch from growth and development into a defense mode, rejecting most potentially harmful microbes. The elicitors are essential structures for pathogen survival and are conserved among pathogens. The conserved microbe-specific molecules, referred to as microbe- or pathogen-associated molecular patterns (MAMPs or PAMPs), are recognized by the plant innate immune systems pattern recognition receptors (PRRs). General elicitors like flagellin (Flg), elongation factor Tu (EF-Tu), peptidoglycan (PGN), lipopolysaccharides (LPS), Ax21 (Activator of XA21-mediated immunity in rice), fungal chitin, and β-glucans from oomycetes are recognized by plant surface localized PRRs. Several of the MAMPs and their corresponding PRRs have, in recent years, been identified. This review focuses on the current knowledge regarding important MAMPs from bacteria, fungi, and oomycetes, their structure, the plant PRRs that recognizes them, and how they induce MAMP-triggered immunity (MTI) in plants. PMID:23720666

  8. Bacterial Outer Membrane Vesicles Induce Plant Immune Responses.

    PubMed

    Bahar, Ofir; Mordukhovich, Gideon; Luu, Dee Dee; Schwessinger, Benjamin; Daudi, Arsalan; Jehle, Anna Kristina; Felix, Georg; Ronald, Pamela C

    2016-05-01

    Gram-negative bacteria continuously pinch off portions of their outer membrane, releasing membrane vesicles. These outer membrane vesicles (OMVs) are involved in multiple processes including cell-to-cell communication, biofilm formation, stress tolerance, horizontal gene transfer, and virulence. OMVs are also known modulators of the mammalian immune response. Despite the well-documented role of OMVs in mammalian-bacterial communication, their interaction with plants is not well studied. To examine whether OMVs of plant pathogens modulate the plant immune response, we purified OMVs from four different plant pathogens and used them to treat Arabidopsis thaliana. OMVs rapidly induced a reactive oxygen species burst, medium alkalinization, and defense gene expression in A. thaliana leaf discs, cell cultures, and seedlings, respectively. Western blot analysis revealed that EF-Tu is present in OMVs and that it serves as an elicitor of the plant immune response in this form. Our results further show that the immune coreceptors BAK1 and SOBIR1 mediate OMV perception and response. Taken together, our results demonstrate that plants can detect and respond to OMV-associated molecules by activation of their immune system, revealing a new facet of plant-bacterial interactions. PMID:26926999

  9. Bacterial Outer Membrane Vesicles Induce Plant Immune Responses.

    PubMed

    Bahar, Ofir; Mordukhovich, Gideon; Luu, Dee Dee; Schwessinger, Benjamin; Daudi, Arsalan; Jehle, Anna Kristina; Felix, Georg; Ronald, Pamela C

    2016-05-01

    Gram-negative bacteria continuously pinch off portions of their outer membrane, releasing membrane vesicles. These outer membrane vesicles (OMVs) are involved in multiple processes including cell-to-cell communication, biofilm formation, stress tolerance, horizontal gene transfer, and virulence. OMVs are also known modulators of the mammalian immune response. Despite the well-documented role of OMVs in mammalian-bacterial communication, their interaction with plants is not well studied. To examine whether OMVs of plant pathogens modulate the plant immune response, we purified OMVs from four different plant pathogens and used them to treat Arabidopsis thaliana. OMVs rapidly induced a reactive oxygen species burst, medium alkalinization, and defense gene expression in A. thaliana leaf discs, cell cultures, and seedlings, respectively. Western blot analysis revealed that EF-Tu is present in OMVs and that it serves as an elicitor of the plant immune response in this form. Our results further show that the immune coreceptors BAK1 and SOBIR1 mediate OMV perception and response. Taken together, our results demonstrate that plants can detect and respond to OMV-associated molecules by activation of their immune system, revealing a new facet of plant-bacterial interactions.

  10. Plant innate immunity against human bacterial pathogens

    PubMed Central

    Melotto, Maeli; Panchal, Shweta; Roy, Debanjana

    2014-01-01

    Certain human bacterial pathogens such as the enterohemorrhagic Escherichia coli and Salmonella enterica are not proven to be plant pathogens yet. Nonetheless, under certain conditions they can survive on, penetrate into, and colonize internal plant tissues causing serious food borne disease outbreaks. In this review, we highlight current understanding on the molecular mechanisms of plant responses against human bacterial pathogens and discuss salient common and contrasting themes of plant interactions with phytopathogens or human pathogens. PMID:25157245

  11. Recent insights into brassinosteroid signaling in plants: its dual control of plant immunity and stomatal development.

    PubMed

    Kong, Xiangpei; Pan, Jiaowen; Cai, Guohua; Li, Dequan

    2012-11-01

    Brassinosteroid (BR) signaling, plant innate immunity, and stomatal developments are three pathways that are initiated by receptor-like kinases. This commentary focuses on the latest findings in the role of BR signaling in plant immunity and stomatal development that provide some insight into the molecular mechanism of the BR signal pathway interacting with other receptor signaling pathways.

  12. Pathogenicity of and plant immunity to soft rot pectobacteria

    PubMed Central

    Davidsson, Pär R.; Kariola, Tarja; Niemi, Outi; Palva, E. T.

    2013-01-01

    Soft rot pectobacteria are broad host range enterobacterial pathogens that cause disease on a variety of plant species including the major crop potato. Pectobacteria are aggressive necrotrophs that harbor a large arsenal of plant cell wall-degrading enzymes as their primary virulence determinants. These enzymes together with additional virulence factors are employed to macerate the host tissue and promote host cell death to provide nutrients for the pathogens. In contrast to (hemi)biotrophs such as Pseudomonas, type III secretion systems (T3SS) and T3 effectors do not appear central to pathogenesis of pectobacteria. Indeed, recent genomic analysis of several Pectobacterium species including the emerging pathogen Pectobacterium wasabiae has shown that many strains lack the entire T3SS as well as the T3 effectors. Instead, this analysis has indicated the presence of novel virulence determinants. Resistance to broad host range pectobacteria is complex and does not appear to involve single resistance genes. Instead, activation of plant innate immunity systems including both SA (salicylic acid) and JA (jasmonic acid)/ET (ethylene)-mediated defenses appears to play a central role in attenuation of Pectobacterium virulence. These defenses are triggered by detection of pathogen-associated molecular patterns (PAMPs) or recognition of modified-self such as damage-associated molecular patterns (DAMPs) and result in enhancement of basal immunity (PAMP/DAMP-triggered immunity or pattern-triggered immunity, PTI). In particular plant cell wall fragments released by the action of the degradative enzymes secreted by pectobacteria are major players in enhanced immunity toward these pathogens. Most notably bacterial pectin-degrading enzymes release oligogalacturonide (OG) fragments recognized as DAMPs activating innate immune responses. Recent progress in understanding OG recognition and signaling allows novel genetic screens for OG-insensitive mutants and will provide new insights

  13. Towards reconstitution of membrane fusion mediated by SNAREs and other synaptic proteins

    PubMed Central

    Brunger, Axel T.; Cipriano, Daniel J.; Diao, Jiajie

    2015-01-01

    Abstract Proteoliposomes have been widely used for in vitro studies of membrane fusion mediated by synaptic proteins. Initially, such studies were made with large unsynchronized ensembles of vesicles. Such ensemble assays limited the insights into the SNARE-mediated fusion mechanism that could be obtained from them. Single particle microscopy experiments can alleviate many of these limitations but they pose significant technical challenges. Here we summarize various approaches that have enabled studies of fusion mediated by SNAREs and other synaptic proteins at a single-particle level. Currently available methods are described and their advantages and limitations are discussed. PMID:25788028

  14. VIP1: linking Agrobacterium-mediated transformation to plant immunity?

    PubMed

    Liu, Yukun; Kong, Xiangpei; Pan, Jiaowen; Li, Dequan

    2010-08-01

    Agrobacterium tumefaciens is the most efficient vehicle used today for the production of transgenic plants and plays an essential role in basic scientific research and in agricultural biotechnology. Previously, plant VirE2-interacting protein 1 (VIP1) was shown to play a role in Agrobacterium-mediated transformation. Recent reports demonstrate that VIP1, as one of the bZIP transcription factors, is also involved in plant immunity responses. Agrobacterium is able to activate and abuse VIP1 for transformation. These findings highlight Agrobacterium-host interaction and unveil how Agrobacterium hijacks host cellular mechanism for its own benefit. This review focuses on the roles played by VIP1 in Agrobacterium-mediated transformation and plant immunity. PMID:20473505

  15. VIP1: linking Agrobacterium-mediated transformation to plant immunity?

    PubMed

    Liu, Yukun; Kong, Xiangpei; Pan, Jiaowen; Li, Dequan

    2010-08-01

    Agrobacterium tumefaciens is the most efficient vehicle used today for the production of transgenic plants and plays an essential role in basic scientific research and in agricultural biotechnology. Previously, plant VirE2-interacting protein 1 (VIP1) was shown to play a role in Agrobacterium-mediated transformation. Recent reports demonstrate that VIP1, as one of the bZIP transcription factors, is also involved in plant immunity responses. Agrobacterium is able to activate and abuse VIP1 for transformation. These findings highlight Agrobacterium-host interaction and unveil how Agrobacterium hijacks host cellular mechanism for its own benefit. This review focuses on the roles played by VIP1 in Agrobacterium-mediated transformation and plant immunity.

  16. Immunization against Rabies with Plant-Derived Antigen

    NASA Astrophysics Data System (ADS)

    Modelska, Anna; Dietzschold, Bernard; Sleysh, N.; Fu, Zhen Fang; Steplewski, Klaudia; Hooper, D. Craig; Koprowski, Hilary; Yusibov, Vidadi

    1998-03-01

    We previously demonstrated that recombinant plant virus particles containing a chimeric peptide representing two rabies virus epitopes stimulate virus neutralizing antibody synthesis in immunized mice. We show here that mice immunized intraperitoneally or orally (by gastric intubation or by feeding on virus-infected spinach leaves) with engineered plant virus particles containing rabies antigen mount a local and systemic immune response. After the third dose of antigen, given intraperitoneally, 40% of the mice were protected against challenge infection with a lethal dose of rabies virus. Oral administration of the antigen stimulated serum IgG and IgA synthesis and ameliorated the clinical signs caused by intranasal infection with an attenuated rabies virus strain.

  17. Immunization against rabies with plant-derived antigen

    PubMed Central

    Modelska, Anna; Dietzschold, Bernard; Sleysh, N.; Fu, Zhen Fang; Steplewski, Klaudia; Hooper, D. Craig; Koprowski, Hilary; Yusibov, Vidadi

    1998-01-01

    We previously demonstrated that recombinant plant virus particles containing a chimeric peptide representing two rabies virus epitopes stimulate virus neutralizing antibody synthesis in immunized mice. We show here that mice immunized intraperitoneally or orally (by gastric intubation or by feeding on virus-infected spinach leaves) with engineered plant virus particles containing rabies antigen mount a local and systemic immune response. After the third dose of antigen, given intraperitoneally, 40% of the mice were protected against challenge infection with a lethal dose of rabies virus. Oral administration of the antigen stimulated serum IgG and IgA synthesis and ameliorated the clinical signs caused by intranasal infection with an attenuated rabies virus strain. PMID:9482911

  18. Pathogen-Secreted Proteases Activate a Novel Plant Immune Pathway

    PubMed Central

    Cheng, Zhenyu; Li, Jian-Feng; Niu, Yajie; Zhang, Xue-Cheng; Woody, Owen Z.; Xiong, Yan; Djonović, Slavica; Millet, Yves; Bush, Jenifer; McConkey, Brendan J.; Sheen, Jen; Ausubel, Frederick M.

    2015-01-01

    Mitogen-Activated Protein Kinase (MAPK) cascades play central roles in innate immune signaling networks in plants and animals1,2. In plants, however, the molecular mechanisms of how signal perception is transduced to MAPK activation remain elusive1. We report that pathogen-secreted proteases activate a previously unknown signaling pathway in Arabidopsis thaliana involving the Gα, Gβ and Gγ subunits of heterotrimeric G-protein complexes, which function upstream of a MAPK cascade. In this pathway, Receptor for Activated C Kinase 1 (RACK1) functions as a novel scaffold that binds to the Gβ subunit as well as to all three tiers of the MAPK cascade, thereby linking upstream G protein signaling to downstream activation of a MAPK cascade. The protease-G protein-RACK1-MAPK cascade modules identified in these studies are distinct from previously described plant immune signaling pathways such as the one elicited by bacterial flagellin, in which G proteins function downstream of or in parallel to a MAPK cascade without the involvement of the RACK1 scaffolding protein. The discovery of the novel protease-mediated immune signaling pathway described here was facilitated by the use of the broad host range, opportunistic bacterial pathogen Pseudomonas aeruginosa. The ability of P. aeruginosa to infect both plants and animals makes it an excellent model to identify novel types of immunoregulatory strategies that account for its niche adaptation to diverse host tissues and immune systems. PMID:25731164

  19. Chemical inducers of systemic immunity in plants.

    PubMed

    Gao, Qing-Ming; Kachroo, Aardra; Kachroo, Pradeep

    2014-04-01

    Systemic acquired resistance (SAR) is a highly desirable form of resistance that protects against a broad-spectrum of related or unrelated pathogens. SAR involves the generation of multiple signals at the site of primary infection, which arms distal portions against subsequent secondary infections. The last decade has witnessed considerable progress, and a number of chemical signals contributing to SAR have been isolated and characterized. The diverse chemical nature of these chemicals had led to the growing belief that SAR might involve interplay of multiple diverse and independent signals. However, recent results suggest that coordinated signalling from diverse signalling components facilitates SAR in plants. This review mainly discusses organized signalling by two such chemicals, glycerol-3-phoshphate and azelaic acid, and the role of basal salicylic acid levels in G3P-conferred SAR.

  20. Contribution of Small RNA Pathway Components in Plant Immunity

    PubMed Central

    Seo, Jang-Kyun; Wu, Jianguo; Lii, Yifan; Li, Yi; Jin, Hailing

    2013-01-01

    Small RNAs regulate a multitude of cellular processes, including development, stress responses, metabolism, and maintenance of genome integrity, in a sequence-specific manner. Accumulating evidence reveals that host endogenous small RNAs and small RNA pathway components play important roles in plant immune responses against various pathogens, including bacteria, fungi, oomycetes, and viruses. Small-RNA-mediated defense responses are regulated through diverse pathways and the components of these pathways, including Dicer-like proteins, RNA-dependent RNA polymerases, Argonaute proteins, and RNA polymerase IV and V, exhibit functional specificities as well as redundancy. In this review, we summarize the recent insights revealed mainly through the examination of two model plants, Arabidopsis and rice, with a primary focus on our emerging understanding of how these small RNA pathway components contribute to plant immunity. PMID:23489060

  1. R proteins as fundamentals of plant innate immunity.

    PubMed

    Głowacki, Sylwester; Macioszek, Violetta K; Kononowicz, Andrzej K

    2011-03-01

    Plants are attacked by a wide spectrum of pathogens, being the targets of viruses, bacteria, fungi, protozoa, nematodes and insects. Over the course of their evolution, plants have developed numerous defense mechanisms including the chemical and physical barriers that are constitutive elements of plant cell responses locally and/or systemically. However, the modern approach in plant sciences focuses on the evolution and role of plant protein receptors corresponding to specific pathogen effectors. The recognition of an invader's molecules could be in most cases a prerequisite sine qua non for plant survival. Although the predicted three-dimensional structure of plant resistance proteins (R) is based on research on their animal homologs, advanced technologies in molecular biology and bioinformatics tools enable the investigation or prediction of interaction mechanisms for specific receptors with pathogen effectors. Most of the identified R proteins belong to the NBS-LRR family. The presence of other domains (including the TIR domain) apart from NBS and LRR is fundamental for the classification of R proteins into subclasses. Recently discovered additional domains (e.g. WRKY) of R proteins allowed the examination of their localization in plant cells and the role they play in signal transduction during the plant resistance response to biotic stress factors. This review focuses on the current state of knowledge about the NBS-LRR family of plant R proteins: their structure, function and evolution, and the role they play in plant innate immunity.

  2. Carbohydrates in plant immunity and plant protection: roles and potential application as foliar sprays

    PubMed Central

    Trouvelot, Sophie; Héloir, Marie-Claire; Poinssot, Benoît; Gauthier, Adrien; Paris, Franck; Guillier, Christelle; Combier, Maud; Trdá, Lucie; Daire, Xavier; Adrian, Marielle

    2014-01-01

    Increasing interest is devoted to carbohydrates for their roles in plant immunity. Some of them are elicitors of plant defenses whereas other ones act as signaling molecules in a manner similar to phytohormones. This review first describes the main classes of carbohydrates associated to plant immunity, their role and mode of action. More precisely, the state of the art about perception of “PAMP, MAMP, and DAMP (Pathogen-, Microbe-, Damage-Associated Molecular Patterns) type” oligosaccharides is presented and examples of induced defense events are provided. A particular attention is paid to the structure/activity relationships of these compounds. The role of sugars as signaling molecules, especially in plant microbe interactions, is also presented. Secondly, the potentialities and limits of foliar sprays of carbohydrates to stimulate plant immunity for crop protection against diseases are discussed, with focus on the roles of the leaf cuticle and phyllosphere microflora. PMID:25408694

  3. A Plant-Derived Multi-HIV Antigen Induces Broad Immune Responses in Orally Immunized Mice.

    PubMed

    Rubio-Infante, Néstor; Govea-Alonso, Dania O; Romero-Maldonado, Andrea; García-Hernández, Ana Lilia; Ilhuicatzi-Alvarado, Damaris; Salazar-González, Jorge A; Korban, Schuyler S; Rosales-Mendoza, Sergio; Moreno-Fierros, Leticia

    2015-07-01

    Multi-HIV, a multiepitopic protein derived from both gp120 and gp41 envelope proteins of the human immunodeficiency virus (HIV), has been proposed as a vaccine prototype capable of inducing broad immune responses, as it carries various B and T cell epitopes from several HIV strains. In this study, the immunogenic properties of a Multi-HIV expressed in tobacco chloroplasts are evaluated in test mice. BALB/c mice orally immunized with tobacco-derived Multi-HIV have elicited antibody responses, including both the V3 loop of gp120 and the ELDKWA epitope of gp41. Based on splenocyte proliferation assays, stimulation with epitopes of the C4, V3 domain of gp120, and the ELDKWA domain of gp41 elicits positive cellular responses. Furthermore, specific interferon gamma production is observed in both CD4+ and CD8+ T cells stimulated with HIV peptides. These results demonstrate that plant-derived Multi-HIV induces T helper-specific responses. Altogether, these findings illustrate the immunogenic potential of plant-derived Multi-HIV in an oral immunization scheme. The potential of this low-cost immunization approach and its implications on HIV/AIDS vaccine development are discussed. PMID:25779638

  4. Sweet immunity in the plant circadian regulatory network.

    PubMed

    Bolouri Moghaddam, Mohammad Reza; Van den Ende, Wim

    2013-04-01

    All organisms have an internal timing mechanism, termed the circadian clock, to anticipate the light/dark cycle. The clock, with an oscillating rhythm that approximates 24h, is a rather robust system persisting to a great extent in continuous light and dark. It is widely accepted that plant growth and development are regulated by the clock, hormones, and sugar signals. On the one hand, sugar signalling can affect circadian rhythms by altering the expression pattern of clock-regulated genes. More in particular, the clock seems to be particularly sensitive to sucrose-mediated signalling which is also associated with immunity and abiotic stress responses. Also, hormonal interaction with the clock can contribute to appropriate plant immune responses. Recent data show a prominent role for the clock in growth and stress responses. On the other hand, the clock seems to be essential in controlling the gene expression and activity of an array of carbohydrate-metabolizing enzymes, suggesting a complex reciprocal relationship between the clock and metabolic signalling processes. Therefore, the clock fulfils a crucial role at the heart of cellular networks. The players involved in the complex plant circadian network and their possible contribution to the novel 'sweet immunity' concept are discussed.

  5. Timing of plant immune responses by a central circadian regulator.

    PubMed

    Wang, Wei; Barnaby, Jinyoung Yang; Tada, Yasuomi; Li, Hairi; Tör, Mahmut; Caldelari, Daniela; Lee, Dae-un; Fu, Xiang-Dong; Dong, Xinnian

    2011-02-01

    The principal immune mechanism against biotrophic pathogens in plants is the resistance (R)-gene-mediated defence. It was proposed to share components with the broad-spectrum basal defence machinery. However, the underlying molecular mechanism is largely unknown. Here we report the identification of novel genes involved in R-gene-mediated resistance against downy mildew in Arabidopsis and their regulatory control by the circadian regulator, CIRCADIAN CLOCK-ASSOCIATED 1 (CCA1). Numerical clustering based on phenotypes of these gene mutants revealed that programmed cell death (PCD) is the major contributor to resistance. Mutants compromised in the R-gene-mediated PCD were also defective in basal resistance, establishing an interconnection between these two distinct defence mechanisms. Surprisingly, we found that these new defence genes are under circadian control by CCA1, allowing plants to 'anticipate' infection at dawn when the pathogen normally disperses the spores and time immune responses according to the perception of different pathogenic signals upon infection. Temporal control of the defence genes by CCA1 differentiates their involvement in basal and R-gene-mediated defence. Our study has revealed a key functional link between the circadian clock and plant immunity.

  6. Ca(2+)/calmodulin regulates salicylic-acid-mediated plant immunity.

    PubMed

    Du, Liqun; Ali, Gul S; Simons, Kayla A; Hou, Jingguo; Yang, Tianbao; Reddy, A S N; Poovaiah, B W

    2009-02-26

    Intracellular calcium transients during plant-pathogen interactions are necessary early events leading to local and systemic acquired resistance. Salicylic acid, a critical messenger, is also required for both of these responses, but whether and how salicylic acid level is regulated by Ca(2+) signalling during plant-pathogen interaction is unclear. Here we report a mechanism connecting Ca(2+) signal to salicylic-acid-mediated immune response through calmodulin, AtSR1 (also known as CAMTA3), a Ca(2+)/calmodulin-binding transcription factor, and EDS1, an established regulator of salicylic acid level. Constitutive disease resistance and elevated levels of salicylic acid in loss-of-function alleles of Arabidopsis AtSR1 suggest that AtSR1 is a negative regulator of plant immunity. This was confirmed by epistasis analysis with mutants of compromised salicylic acid accumulation and disease resistance. We show that AtSR1 interacts with the promoter of EDS1 and represses its expression. Furthermore, Ca(2+)/calmodulin-binding to AtSR1 is required for suppression of plant defence, indicating a direct role for Ca(2+)/calmodulin in regulating the function of AtSR1. These results reveal a previously unknown regulatory mechanism linking Ca(2+) signalling to salicylic acid level.

  7. Signalling crosstalk in light stress and immune reactions in plants.

    PubMed

    Trotta, Andrea; Rahikainen, Moona; Konert, Grzegorz; Finazzi, Giovanni; Kangasjärvi, Saijaliisa

    2014-04-19

    The evolutionary history of plants is tightly connected with the evolution of microbial pathogens and herbivores, which use photosynthetic end products as a source of life. In these interactions, plants, as the stationary party, have evolved sophisticated mechanisms to sense, signal and respond to the presence of external stress agents. Chloroplasts are metabolically versatile organelles that carry out fundamental functions in determining appropriate immune reactions in plants. Besides photosynthesis, chloroplasts host key steps in the biosynthesis of amino acids, stress hormones and secondary metabolites, which have a great impact on resistance against pathogens and insect herbivores. Changes in chloroplast redox signalling pathways and reactive oxygen species metabolism also mediate local and systemic signals, which modulate plant resistance to light stress and disease. Moreover, interplay among chloroplastic signalling networks and plasma membrane receptor kinases is emerging as a key mechanism that modulates stress responses in plants. This review highlights the central role of chloroplasts in the signalling crosstalk that essentially determines the outcome of plant-pathogen interactions in plants.

  8. Cysteine homeostasis plays an essential role in plant immunity.

    PubMed

    Álvarez, Consolación; Bermúdez, M Ángeles; Romero, Luis C; Gotor, Cecilia; García, Irene

    2012-01-01

    • Cysteine is the metabolic precursor of essential biomolecules such as vitamins, cofactors, antioxidants and many defense compounds. The last step of cysteine metabolism is catalysed by O-acetylserine(thiol)lyase (OASTL), which incorporates reduced sulfur into O-acetylserine to produce cysteine. In Arabidopsis thaliana, the main OASTL isoform OAS-A1 and the cytosolic desulfhydrase DES1, which degrades cysteine, contribute to the cytosolic cysteine homeostasis. • Meta-analysis of the transcriptomes of knockout plants for OAS-A1 and for DES1 show a high correlation with the biotic stress series in both cases. • The study of the response of knockout mutants to plant pathogens shows that des1 mutants behave as constitutive systemic acquired resistance mutants, with high resistance to biotrophic and necrotrophic pathogens, salicylic acid accumulation and WRKY54 and PR1 induction, while oas-a1 knockout mutants are more sensitive to biotrophic and necrotrophic pathogens. However, oas-a1 knockout mutants lack the hypersensitive response associated with the effector-triggered immunity elicited by Pseudomonas syringae pv. tomato DC3000 avrRpm1. • Our results highlight the role of cysteine as a crucial metabolite in the plant immune response.

  9. Proteomics of effector-triggered immunity (ETI) in plants

    PubMed Central

    Hurley, Brenden; Subramaniam, Rajagopal; Guttman, David S; Desveaux, Darrell

    2014-01-01

    Effector-triggered immunity (ETI) was originally termed gene-for-gene resistance and dates back to fundamental observations of flax resistance to rust fungi by Harold Henry Flor in the 1940s. Since then, genetic and biochemical approaches have defined our current understanding of how plant “resistance” proteins recognize microbial effectors. More recently, proteomic approaches have expanded our view of the protein landscape during ETI and contributed significant advances to our mechanistic understanding of ETI signaling. Here we provide an overview of proteomic techniques that have been used to study plant ETI including both global and targeted approaches. We discuss the challenges associated with ETI proteomics and highlight specific examples from the literature, which demonstrate how proteomics is advancing the ETI research field. PMID:25513776

  10. Proteomics of effector-triggered immunity (ETI) in plants.

    PubMed

    Hurley, Brenden; Subramaniam, Rajagopal; Guttman, David S; Desveaux, Darrell

    2014-01-01

    Effector-triggered immunity (ETI) was originally termed gene-for-gene resistance and dates back to fundamental observations of flax resistance to rust fungi by Harold Henry Flor in the 1940s. Since then, genetic and biochemical approaches have defined our current understanding of how plant "resistance" proteins recognize microbial effectors. More recently, proteomic approaches have expanded our view of the protein landscape during ETI and contributed significant advances to our mechanistic understanding of ETI signaling. Here we provide an overview of proteomic techniques that have been used to study plant ETI including both global and targeted approaches. We discuss the challenges associated with ETI proteomics and highlight specific examples from the literature, which demonstrate how proteomics is advancing the ETI research field. PMID:25513776

  11. Root assays to study pattern-triggered immunity in plant-nematode interactions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plants employ extracellular immune receptors to perceive conserved pathogen-associated molecular patterns (PAMPs), triggering the first layer of defense known as pattern-triggered immunity (PTI). The understanding of PTI is mainly based on the studies focusing on leaves. Plants are vulnerable to att...

  12. The Fundamental Role of NOX Family Proteins in Plant Immunity and Their Regulation

    PubMed Central

    Wang, Ya-Jing; Wei, Xiao-Yong; Jing, Xiu-Qing; Chang, Yan-Li; Hu, Chun-Hong; Wang, Xiang; Chen, Kun-Ming

    2016-01-01

    NADPH oxidases (NOXs), also known as respiratory burst oxidase homologs (RBOHs), are the major source of reactive oxygen species (ROS), and are involved in many important processes in plants such as regulation of acclimatory signaling and programmed cell death (PCD). Increasing evidence shows that NOXs play crucial roles in plant immunity and their functions in plant immune responses are not as separate individuals but with other signal molecules such as kinases, Rac/Rop small GTPases and hormones, mediating a series of signal transmissions. In a similar way, NOX-mediated signaling also participates in abiotic stress response of plants. We summarized here the complex role and regulation mechanism of NOXs in mediating plant immune response, and the viewpoint that abiotic stress response of plants may be a kind of special plant immunity is also proposed. PMID:27240354

  13. Influences of Plant Traits on Immune Responses of Specialist and Generalist Herbivores

    PubMed Central

    Lampert, Evan

    2012-01-01

    Specialist and generalist insect herbivore species often differ in how they respond to host plant traits, particularly defensive traits, and these responses can include weakened or strengthened immune responses to pathogens and parasites. Accurate methods to measure immune response in the presence and absence of pathogens and parasites are necessary to determine whether susceptibility to these natural enemies is reduced or increased by host plant traits. Plant chemical traits are particularly important in that host plant metabolites may function as antioxidants beneficial to the immune response, or interfere with the immune response of both specialist and generalist herbivores. Specialist herbivores that are adapted to process and sometimes accumulate specific plant compounds may experience high metabolic demands that may decrease immune response, whereas the metabolic demands of generalist species differ due to more broad-substrate enzyme systems. However, the direct deleterious effects of plant compounds on generalist herbivores may weaken their immune responses. Further research in this area is important given that the ecological relevance of plant traits to herbivore immune responses is equally important in natural systems and agroecosystems, due to potential incompatibility of some host plant species and cultivars with biological control agents of herbivorous pests. PMID:26466545

  14. The transcriptional regulator BZR1 mediates trade-off between plant innate immunity and growth

    PubMed Central

    Lozano-Durán, Rosa; Macho, Alberto P; Boutrot, Freddy; Segonzac, Cécile; Somssich, Imre E; Zipfel, Cyril

    2013-01-01

    The molecular mechanisms underlying the trade-off between plant innate immunity and steroid-mediated growth are controversial. Here, we report that activation of the transcription factor BZR1 is required and sufficient for suppression of immune signaling by brassinosteroids (BR). BZR1 induces the expression of several WRKY transcription factors that negatively control early immune responses. In addition, BZR1 associates with WRKY40 to mediate the antagonism between BR and immune signaling. We reveal that BZR1-mediated inhibition of immunity is particularly relevant when plant fast growth is required, such as during etiolation. Thus, BZR1 acts as an important regulator mediating the trade-off between growth and immunity upon integration of environmental cues. DOI: http://dx.doi.org/10.7554/eLife.00983.001 PMID:24381244

  15. Soil immune responses: Soil microbiomes may be harnessed for plant health

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The best examples of microbiome-mediated protection of plants against root pathogens are disease suppressive soils. The characteristics of general and specific disease suppressiveness of soils are strikingly comparable to innate and adaptive immunity in animals. Innate immunity and general soil su...

  16. Generation of protective immune response against anthrax by oral immunization with protective antigen plant-based vaccine.

    PubMed

    Gorantala, Jyotsna; Grover, Sonam; Rahi, Amit; Chaudhary, Prerna; Rajwanshi, Ravi; Sarin, Neera Bhalla; Bhatnagar, Rakesh

    2014-04-20

    In concern with frequent recurrence of anthrax in endemic areas and inadvertent use of its spores as biological weapon, the development of an effective anthrax vaccine suitable for both human and veterinary needs is highly desirable. A simple oral delivery through expression in plant system could offer promising alternative to the current methods that rely on injectable vaccines extracted from bacterial sources. In the present study, we have expressed protective antigen (PA) gene in Indian mustard by Agrobacterium-mediated transformation and in tobacco by plastid transformation. Putative transgenic lines were verified for the presence of transgene and its expression by molecular analysis. PA expressed in transgenic lines was biologically active as evidenced by macrophage lysis assay. Intraperitoneal (i.p.) and oral immunization with plant PA in murine model indicated high serum PA specific IgG and IgA antibody titers. PA specific mucosal immune response was noted in orally immunized groups. Further, antibodies indicated lethal toxin neutralizing potential in-vitro and conferred protection against in-vivo toxin challenge. Oral immunization experiments demonstrated generation of immunoprotective response in mice. Thus, our study examines the feasibility of oral PA vaccine expressed in an edible plant system against anthrax.

  17. Independently Evolved Virulence Effectors Converge onto Hubs in a Plant Immune System Network

    PubMed Central

    Mukhtar, M. Shahid; Carvunis, Anne-Ruxandra; Dreze, Matija; Epple, Petra; Steinbrenner, Jens; Moore, Jonathan; Tasan, Murat; Galli, Mary; Hao, Tong; Nishimura, Marc T.; Pevzner, Samuel J.; Donovan, Susan E.; Ghamsari, Lila; Santhanam, Balaji; Romero, Viviana; Poulin, Matthew M.; Gebreab, Fana; Gutierrez, Bryan J.; Tam, Stanley; Monachello, Dario; Boxem, Mike; Harbort, Christopher J.; McDonald, Nathan; Gai, Lantian; Chen, Huaming; He, Yijian; Vandenhaute, Jean; Roth, Frederick P.; Hill, David E.; Ecker, Joseph R.; Vidal, Marc; Beynon, Jim; Braun, Pascal; Dangl, Jeffery L.

    2011-01-01

    Plants generate effective responses to infection by recognizing both conserved and variable pathogen-encoded molecules. Pathogens deploy virulence effector proteins into host cells, where they interact physically with host proteins to modulate defense. We generated a plant-pathogen immune system protein interaction network using effectors from two pathogens spanning the eukaryote-eubacteria divergence, three classes of Arabidopsis immune system proteins and ~8,000 other Arabidopsis proteins. We noted convergence of effectors onto highly interconnected host proteins, and indirect, rather than direct, connections between effectors and plant immune receptors. We demonstrated plant immune system functions for 15 of 17 tested host proteins that interact with effectors from both pathogens. Thus, pathogens from different kingdoms deploy independently evolved virulence proteins that interact with a limited set of highly connected cellular hubs to facilitate their diverse life cycle strategies. PMID:21798943

  18. Plant Immune Responses Against Viruses: How Does a Virus Cause Disease?[OA

    PubMed Central

    Mandadi, Kranthi K.; Scholthof, Karen-Beth G.

    2013-01-01

    Plants respond to pathogens using elaborate networks of genetic interactions. Recently, significant progress has been made in understanding RNA silencing and how viruses counter this apparently ubiquitous antiviral defense. In addition, plants also induce hypersensitive and systemic acquired resistance responses, which together limit the virus to infected cells and impart resistance to the noninfected tissues. Molecular processes such as the ubiquitin proteasome system and DNA methylation are also critical to antiviral defenses. Here, we provide a summary and update of advances in plant antiviral immune responses, beyond RNA silencing mechanisms—advances that went relatively unnoticed in the realm of RNA silencing and nonviral immune responses. We also document the rise of Brachypodium and Setaria species as model grasses to study antiviral responses in Poaceae, aspects that have been relatively understudied, despite grasses being the primary source of our calories, as well as animal feed, forage, recreation, and biofuel needs in the 21st century. Finally, we outline critical gaps, future prospects, and considerations central to studying plant antiviral immunity. To promote an integrated model of plant immunity, we discuss analogous viral and nonviral immune concepts and propose working definitions of viral effectors, effector-triggered immunity, and viral pathogen-triggered immunity. PMID:23709626

  19. 99th Dahlem conference on infection, inflammation and chronic inflammatory disorders: innate immune responses in plants.

    PubMed

    Schulze-Lefert, P

    2010-04-01

    Plants rely exclusively upon mechanisms of innate immunity. Current concepts of the plant innate immune system are based largely on two forms of immunity that engage distinct classes of immune receptors. These receptors enable the recognition of non-self structures that are either conserved between members of a microbial class or specific to individual strains of a microbe. One type of receptor comprises membrane-resident pattern recognition receptors (PRRs) that detect widely conserved microbe-associated molecular patterns (MAMPs) on the cell surface. A second type of mainly intracellular immune sensors, designated resistance (R) proteins, recognizes either the structure or function of strain-specific pathogen effectors that are delivered inside host cells. Phytopathogenic microorganisms have evolved a repertoire of effectors, some of which are delivered into plant cells to sabotage MAMP-triggered immune responses. Plants appear to have also evolved receptors that sense cellular injury by the release and perception of endogenous damage-associated molecular patterns (DAMPs). It is possible that the integration of MAMP and DAMP responses is critical to mount robust MAMP-triggered immunity. This signal integration might help to explain why plants are colonized in nature by remarkably diverse and seemingly asymptomatic microbial communities. PMID:20415853

  20. The Evolutionarily Conserved E3 Ubiquitin Ligase AtCHIP Contributes to Plant Immunity

    PubMed Central

    Copeland, Charles; Ao, Kevin; Huang, Yan; Tong, Meixuizi; Li, Xin

    2016-01-01

    Plants possess a sophisticated immune system to recognize and respond to microbial threats in their environment. The level of immune signaling must be tightly regulated so that immune responses can be quickly activated in the presence of pathogens, while avoiding autoimmunity. HSP90s, along with their diverse array of co-chaperones, forms chaperone complexes that have been shown to play both positive and negative roles in regulating the accumulation of immune receptors and regulators. In this study, we examined the role of AtCHIP, an evolutionarily conserved E3 ligase that was known to interact with chaperones including HSP90s in multicellular organisms including fruit fly, Caenorhabditis elegans, plants and human. Atchip knockout mutants display enhanced disease susceptibility to a virulent oomycete pathogen, and overexpression of AtCHIP causes enhanced disease resistance at low temperature. Although CHIP was reported to target HSP90 for ubiquitination and degradation, accumulation of HSP90.3 was not affected in Atchip plants. In addition, protein accumulation of nucleotide-binding, leucine-rich repeat domain immune receptor (NLR) SNC1 is not altered in Atchip mutant. Thus, while AtCHIP plays a role in immunity, it does not seem to regulate the turnover of HSP90 or SNC1. Further investigation is needed in order to determine the exact mechanism behind AtCHIP’s role in regulating plant immune responses. PMID:27014328

  1. New insights into the regulation of plant immunity by amino acid metabolic pathways.

    PubMed

    Zeier, Jürgen

    2013-12-01

    Besides defence pathways regulated by classical stress hormones, distinct amino acid metabolic pathways constitute integral parts of the plant immune system. Mutations in several genes involved in Asp-derived amino acid biosynthetic pathways can have profound impact on plant resistance to specific pathogen types. For instance, amino acid imbalances associated with homoserine or threonine accumulation elevate plant immunity to oomycete pathogens but not to pathogenic fungi or bacteria. The catabolism of Lys produces the immune signal pipecolic acid (Pip), a cyclic, non-protein amino acid. Pip amplifies plant defence responses and acts as a critical regulator of plant systemic acquired resistance, defence priming and local resistance to bacterial pathogens. Asp-derived pyridine nucleotides influence both pre- and post-invasion immunity, and the catabolism of branched chain amino acids appears to affect plant resistance to distinct pathogen classes by modulating crosstalk of salicylic acid- and jasmonic acid-regulated defence pathways. It also emerges that, besides polyamine oxidation and NADPH oxidase, Pro metabolism is involved in the oxidative burst and the hypersensitive response associated with avirulent pathogen recognition. Moreover, the acylation of amino acids can control plant resistance to pathogens and pests by the formation of protective plant metabolites or by the modulation of plant hormone activity.

  2. Capping protein integrates multiple MAMP signalling pathways to modulate actin dynamics during plant innate immunity.

    PubMed

    Li, Jiejie; Henty-Ridilla, Jessica L; Staiger, Benjamin H; Day, Brad; Staiger, Christopher J

    2015-01-01

    Plants and animals perceive diverse microbe-associated molecular patterns (MAMPs) via pattern recognition receptors and activate innate immune signalling. The actin cytoskeleton has been suggested as a target for innate immune signalling and a key transducer of cellular responses. However, the molecular mechanisms underlying actin remodelling and the precise functions of these rearrangements during innate immunity remain largely unknown. Here we demonstrate rapid actin remodelling in response to several distinct MAMP signalling pathways in plant epidermal cells. The regulation of actin dynamics is a convergence point for basal defence machinery, such as cell wall fortification and transcriptional reprogramming. Our quantitative analyses of actin dynamics and genetic studies reveal that MAMP-stimulated actin remodelling is due to the inhibition of capping protein (CP) by the signalling lipid, phosphatidic acid. In addition, CP promotes resistance against bacterial and fungal phytopathogens. These findings demonstrate that CP is a central target for the plant innate immune response. PMID:26018794

  3. Immunization

    MedlinePlus

    ... a lot worse. Some are even life-threatening. Immunization shots, or vaccinations, are essential. They protect against things like measles, ... B, polio, tetanus, diphtheria, and pertussis (whooping cough). Immunizations are important for adults as well as children. ...

  4. Immunizations

    MedlinePlus

    ... How Can I Help a Friend Who Cuts? Immunizations KidsHealth > For Teens > Immunizations Print A A A ... That Shot? en español Las vacunas Why Are Vaccinations Important? Measles, mumps, and whooping cough may seem ...

  5. Imaging multiple intermediates of single-virus membrane fusion mediated by distinct fusion proteins.

    PubMed

    Joo, Kye-Il; Tai, April; Lee, Chi-Lin; Wong, Clement; Wang, Pin

    2010-09-01

    Membrane fusion plays an essential role in the entry of enveloped viruses into target cells. The merging of viral and target cell membranes is catalyzed by viral fusion proteins, which involves multiple sequential steps in the fusion process. However, the fusion mechanisms mediated by different fusion proteins involve multiple transient intermediates that have not been well characterized. Here, we report a synthetic virus platform that allows us to better understand the different fusion mechanisms driven by the diverse types fusion proteins. The platform consists of lentiviral particles coenveloped with a surface antibody, which serves as the binding protein, along with a fusion protein derived from either influenza virus (HAmu) or Sindbis virus (SINmu). By using a single virus tracking technique, we demonstrated that both HAmu- and SINmu-bearing viruses enter cells through clathrin-dependent endocytosis, but they required different endosomal trafficking routes to initiate viral fusion. Direct observation of single viral fusion events clearly showed that hemifusion mediated by SINmu upon exposure to low pH occurs faster than that mediated by HAmu. Monitoring sequential fusion processes by dual labeling the outer and inner leaflets of viral membranes also revealed that the SINmu-mediated hemifusion intermediate is relatively long-lived as compared with that mediated by HAmu. Taken together, we have demonstrated that the combination of this versatile viral platform with the techniques of single virus tracking can be a powerful tool for revealing molecular details of fusion mediated by various fusion proteins.

  6. Glycerol-3-phosphate is a critical mobile inducer of systemic immunity in plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Glycerol-3-phosphate (G3P) is an important metabolite that contributes to the growth and disease-related physiologies of prokaryotes, plants, animals and humans alike. Here we show that G3P serves as the inducer of an important form of broad-spectrum immunity in plants, termed systemic acquired resi...

  7. A novel nematode effector suppresses plant immunity by activating host reactuve oxygen species-scavenging system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oxidative burst is a hallmark event of the pathogen-associated molecular pattern (PAMP) triggered immunity (PTI), which is the first line of plant defense mechanisms, but it remains unclear how nematodes can overcome this defense mechanism. In this study, we show that plant-parasitic nematode Meloid...

  8. Productive infection of human immunodeficiency virus type 1 in dendritic cells requires fusion-mediated viral entry

    SciTech Connect

    Janas, Alicia M.; Dong, Chunsheng; Wang Jianhua; Wu Li

    2008-06-05

    Human immunodeficiency virus type 1 (HIV-1) enters dendritic cells (DCs) through endocytosis and viral receptor-mediated fusion. Although endocytosis-mediated HIV-1 entry can generate productive infection in certain cell types, including human monocyte-derived macrophages, productive HIV-1 infection in DCs appears to be dependent on fusion-mediated viral entry. It remains to be defined whether endocytosed HIV-1 in DCs can initiate productive infection. Using HIV-1 infection and cellular fractionation assays to measure productive viral infection and entry, here we show that HIV-1 enters monocyte-derived DCs predominately through endocytosis; however, endocytosed HIV-1 cannot initiate productive HIV-1 infection in DCs. In contrast, productive HIV-1 infection in DCs requires fusion-mediated viral entry. Together, these results provide functional evidence in understanding HIV-1 cis-infection of DCs, suggesting that different pathways of HIV-1 entry into DCs determine the outcome of viral infection.

  9. Negative control of BAK1 by protein phosphatase 2A during plant innate immunity

    PubMed Central

    Segonzac, Cécile; Macho, Alberto P; Sanmartín, Maite; Ntoukakis, Vardis; Sánchez-Serrano, José Juan; Zipfel, Cyril

    2014-01-01

    Recognition of pathogen-associated molecular patterns (PAMPs) by surface-localized pattern-recognition receptors (PRRs) activates plant innate immunity, mainly through activation of numerous protein kinases. Appropriate induction of immune responses must be tightly regulated, as many of the kinases involved have an intrinsic high activity and are also regulated by other external and endogenous stimuli. Previous evidences suggest that PAMP-triggered immunity (PTI) is under constant negative regulation by protein phosphatases but the underlying molecular mechanisms remain unknown. Here, we show that protein Ser/Thr phosphatase type 2A (PP2A) controls the activation of PRR complexes by modulating the phosphostatus of the co-receptor and positive regulator BAK1. A potential PP2A holoenzyme composed of the subunits A1, C4, and B’η/ζ inhibits immune responses triggered by several PAMPs and anti-bacterial immunity. PP2A constitutively associates with BAK1 in planta. Impairment in this PP2A-based regulation leads to increased steady-state BAK1 phosphorylation, which can poise enhanced immune responses. This work identifies PP2A as an important negative regulator of plant innate immunity that controls BAK1 activation in surface-localized immune receptor complexes. PMID:25085430

  10. The mucosal immune response to plant-derived vaccines.

    PubMed

    Hefferon, Kathleen Laura

    2010-10-01

    Transgenic plants present enormous potential as one of the most cost-effective and safe systems for large-scale production of proteins for industrial, pharmaceutical, veterinary and agricultural uses. Heat-stable plant-derived vaccines that are administered orally could in effect enhance vaccine coverage in children and infants, particularly in developing countries. Here we discuss the current status of plant-derived vaccines and their potential to champion the battle against infectious diseases in the least developed countries.

  11. Lipid Transfer Proteins As Components of the Plant Innate Immune System: Structure, Functions, and Applications

    PubMed Central

    Finkina, E. I.; Melnikova, D. N.; Bogdanov, I. V.; Ovchinnikova, T. V.

    2016-01-01

    Among a variety of molecular factors of the plant innate immune system, small proteins that transfer lipids and exhibit a broad spectrum of biological activities are of particular interest. These are lipid transfer proteins (LTPs). LTPs are interesting to researchers for three main features. The first feature is the ability of plant LTPs to bind and transfer lipids, whereby these proteins got their name and were combined into one class. The second feature is that LTPs are defense proteins that are components of plant innate immunity. The third feature is that LTPs constitute one of the most clinically important classes of plant allergens. In this review, we summarize the available data on the plant LTP structure, biological properties, diversity of functions, mechanisms of action, and practical applications, emphasizing their role in plant physiology and their significance in human life. PMID:27437139

  12. Plant signaling: brassinosteroids, immunity and effectors are BAK !

    PubMed

    Vert, Grégory

    2008-10-28

    Plants use the same set of co-receptors to mediate distinct responses to external signals. Brassinosteroid signaling serves as a test case to unravel the mechanisms of receptor-co-receptor activation and initiation of a specific signaling cascade.

  13. High levels of cyclic-di-GMP in plant-associated Pseudomonas correlate with evasion of plant immunity.

    PubMed

    Pfeilmeier, Sebastian; Saur, Isabel Marie-Luise; Rathjen, John Paul; Zipfel, Cyril; Malone, Jacob George

    2016-05-01

    The plant innate immune system employs plasma membrane-localized receptors that specifically perceive pathogen/microbe-associated molecular patterns (PAMPs/MAMPs). This induces a defence response called pattern-triggered immunity (PTI) to fend off pathogen attack. Commensal bacteria are also exposed to potential immune recognition and must employ strategies to evade and/or suppress PTI to successfully colonize the plant. During plant infection, the flagellum has an ambiguous role, acting as both a virulence factor and also as a potent immunogen as a result of the recognition of its main building block, flagellin, by the plant pattern recognition receptors (PRRs), including FLAGELLIN SENSING2 (FLS2). Therefore, strict control of flagella synthesis is especially important for plant-associated bacteria. Here, we show that cyclic-di-GMP [bis-(3'-5')-cyclic di-guanosine monophosphate], a central regulator of bacterial lifestyle, is involved in the evasion of PTI. Elevated cyclic-di-GMP levels in the pathogen Pseudomonas syringae pv. tomato (Pto) DC3000, the opportunist P. aeruginosa PAO1 and the commensal P. protegens Pf-5 inhibit flagellin synthesis and help the bacteria to evade FLS2-mediated signalling in Nicotiana benthamiana and Arabidopsis thaliana. Despite this, high cellular cyclic-di-GMP concentrations were shown to drastically reduce the virulence of Pto DC3000 during plant infection. We propose that this is a result of reduced flagellar motility and/or additional pleiotropic effects of cyclic-di-GMP signalling on bacterial behaviour.

  14. Secondary metabolites in plant innate immunity: conserved function of divergent chemicals.

    PubMed

    Piasecka, Anna; Jedrzejczak-Rey, Nicolas; Bednarek, Paweł

    2015-05-01

    Plant secondary metabolites carry out numerous functions in interactions between plants and a broad range of other organisms. Experimental evidence strongly supports the indispensable contribution of many constitutive and pathogen-inducible phytochemicals to plant innate immunity. Extensive studies on model plant species, particularly Arabidopsis thaliana, have brought significant advances in our understanding of the molecular mechanisms underpinning pathogen-triggered biosynthesis and activation of defensive secondary metabolites. However, despite the proven significance of secondary metabolites in plant response to pathogenic microorganisms, little is known about the precise mechanisms underlying their contribution to plant immunity. This insufficiency concerns information on the dynamics of cellular and subcellular localization of defensive phytochemicals during the encounters with microbial pathogens and precise knowledge on their mode of action. As many secondary metabolites are characterized by their in vitro antimicrobial activity, these compounds were commonly considered to function in plant defense as in planta antibiotics. Strikingly, recent experimental evidence suggests that at least some of these compounds alternatively may be involved in controlling several immune responses that are evolutionarily conserved in the plant kingdom, including callose deposition and programmed cell death.

  15. Does plant immunity play a critical role during initiation of the legume-rhizobium symbiosis?

    PubMed Central

    Tóth, Katalin; Stacey, Gary

    2015-01-01

    Plants are exposed to many different microbes in their habitats. These microbes may be benign or pathogenic, but in some cases they are beneficial for the host. The rhizosphere provides an especially rich palette for colonization by beneficial (associative and symbiotic) microorganisms, which raises the question as to how roots can distinguish such ‘friends’ from possible ‘foes’ (i.e., pathogens). Plants possess an innate immune system that can recognize pathogens, through an arsenal of protein receptors, including receptor-like kinases (RLKs) and receptor-like proteins (RLPs) located at the plasma membrane. In addition, the plant host has intracellular receptors (so called NBS-LRR proteins or R proteins) that directly or indirectly recognize molecules released by microbes into the plant cell. A successful cooperation between legume plants and rhizobia leads to beneficial symbiotic interaction. The key rhizobial, symbiotic signaling molecules [lipo-chitooligosaccharide Nod factors (NF)] are perceived by the host legume plant using lysin motif-domain containing RLKs. Perception of the symbiotic NFs trigger signaling cascades leading to bacterial infection and accommodation of the symbiont in a newly formed root organ, the nodule, resulting in a nitrogen-fixing root nodule symbiosis. The net result of this symbiosis is the intracellular colonization of the plant with thousands of bacteria; a process that seems to occur in spite of the immune ability of plants to prevent pathogen infection. In this review, we discuss the potential of the invading rhizobial symbiont to actively avoid this innate immune response, as well as specific examples of where the plant immune response may modulate rhizobial infection and host range. PMID:26082790

  16. Getting to PTI of bacterial RNAs: Triggering plant innate immunity by extracellular RNAs from bacteria.

    PubMed

    Park, Yong-Soon; Lee, Boyoung; Ryu, Choong-Min

    2016-07-01

    Defense against diverse biotic and abiotic stresses requires the plant to distinguish between self and non-self signaling molecules. Pathogen/microbe-associated molecular patterns (PAMPs/MAMPs) are pivotal for triggering innate immunity in plants. Unlike in animals and humans, the precise roles of nucleic acids in plant innate immunity are unclear. We therefore investigated the effects of infiltration of total Pseudomonas syringae pv. tomato DC3000 (Pto DC3000) RNAs into Arabidopsis plants. The pathogen population was 10-fold lower in bacterial RNAs pre-treated Arabidopsis plants than in the control. Bacterial RNAs purity was confirmed by physical (sonication) and chemical (RNase A and proteinase K digestion) methods. The perception of bacterial RNAs, especially rRNAs, positively regulated mitogen-activated protein kinase (MAPK) and induced a reactive oxygen species burst, callose deposition, salicylic acid (SA) and jasmonic acid (JA) signaling, and defense-related genes. Therefore, bacterial RNAs function as a new MAMP that activates plant innate immunity, providing a new paradigm for plant-microbe interactions. PMID:27301792

  17. Circadian Redox Signaling in Plant Immunity and Abiotic Stress

    PubMed Central

    Spoel, Steven H.

    2014-01-01

    Abstract Significance: Plant crops are critically important to provide quality food and bio-energy to sustain a growing human population. Circadian clocks have been shown to deliver an adaptive advantage to plants, vastly increasing biomass production by efficient anticipation to the solar cycle. Plant stress, on the other hand, whether biotic or abiotic, prevents crops from reaching maximum productivity. Recent Advances: Stress is associated with fluctuations in cellular redox and increased phytohormone signaling. Recently, direct links between circadian timekeeping, redox fluctuations, and hormone signaling have been identified. A direct implication is that circadian control of cellular redox homeostasis influences how plants negate stress to ensure growth and reproduction. Critical Issues: Complex cellular biochemistry leads from perception of stress via hormone signals and formation of reactive oxygen intermediates to a physiological response. Circadian clocks and metabolic pathways intertwine to form a confusing biochemical labyrinth. Here, we aim to find order in this complex matter by reviewing current advances in our understanding of the interface between these networks. Future Directions: Although the link is now clearly defined, at present a key question remains as to what extent the circadian clock modulates redox, and vice versa. Furthermore, the mechanistic basis by which the circadian clock gates redox- and hormone-mediated stress responses remains largely elusive. Antioxid. Redox Signal. 20, 3024–3039. PMID:23941583

  18. Low cost delivery of proteins bioencapsulated in plant cells to human non-immune or immune modulatory cells.

    PubMed

    Xiao, Yuhong; Kwon, Kwang-Chul; Hoffman, Brad E; Kamesh, Aditya; Jones, Noah T; Herzog, Roland W; Daniell, Henry

    2016-02-01

    Targeted oral delivery of GFP fused with a GM1 receptor binding protein (CTB) or human cell penetrating peptide (PTD) or dendritic cell peptide (DCpep) was investigated. Presence of GFP(+) intact plant cells between villi of ileum confirm their protection in the digestive system from acids/enzymes. Efficient delivery of GFP to gut-epithelial cells by PTD or CTB and to M cells by all these fusion tags confirm uptake of GFP in the small intestine. PTD fusion delivered GFP more efficiently to most tissues or organs than the other two tags. GFP was efficiently delivered to the liver by all fusion tags, likely through the gut-liver axis. In confocal imaging studies of human cell lines using purified GFP fused with different tags, GFP signal of DCpep-GFP was only detected within dendritic cells. PTD-GFP was only detected within kidney or pancreatic cells but not in immune modulatory cells (macrophages, dendritic, T, B, or mast cells). In contrast, CTB-GFP was detected in all tested cell types, confirming ubiquitous presence of GM1 receptors. Such low-cost oral delivery of protein drugs to sera, immune system or non-immune cells should dramatically lower their cost by elimination of prohibitively expensive fermentation, protein purification cold storage/transportation and increase patient compliance. PMID:26706477

  19. Role of plant expression systems in antibody production for passive immunization.

    PubMed

    Virdi, Vikram; Depicker, Ann

    2013-01-01

    Passive immunization is a method to achieve immediate protection against infectious agents by administering pathogen-specific antibodies. It has proven to be lifesaving for many acute infections, and it is now also used for cancer treatment. Passive immunization therapies, however, are extremely expensive because they require large amounts of specific antibodies that are produced predominantly in mammalian expression systems. The cost for manufacturing plant-made antibodies is estimated to be comparatively low since plant production systems require relatively less capital investments. In addition, they are not prone to mammalian pathogens, which also eases downstream processing along with making it a safe expression system. Moreover, some of the recent developments in transient expression have enabled rapid, cGMP (current Good Manufacturing Practices) compliant manufacturing of antibodies. Whether lower production costs will be reflected in a lower market price for purified antibodies will be known when more plant-produced antibodies come to the market. Promisingly, the current molecular techniques in the field of in planta expression have enabled high-level production of a variety of antibodies in different plant organs, like roots/tubers/fruits, leaves and seeds, of a variety of plants, like potato, tobacco, maize, rice, tomato and pea, providing a very wide range of possible plant-based passive immunization therapies. For instance, the production of antibodies in edible tissues would allow for a unique, convenient, needle-less, oral passive immunization at the gastric mucosal surface. The technological advances, together with the innate capacity of plant tissues to assemble complex antibodies, will enable carving a niche in the antibody market. This non-exhaustive review aims to shed light on the role of plants as a flexible expression system for passive immunotherapy, which we envisage to progress alongside the conventional production platforms to manufacture

  20. Disease resistance or growth: the role of plant hormones in balancing immune responses and fitness costs

    PubMed Central

    Denancé, Nicolas; Sánchez-Vallet, Andrea; Goffner, Deborah; Molina, Antonio

    2013-01-01

    Plant growth and response to environmental cues are largely governed by phytohormones. The plant hormones ethylene, jasmonic acid, and salicylic acid (SA) play a central role in the regulation of plant immune responses. In addition, other plant hormones, such as auxins, abscisic acid (ABA), cytokinins, gibberellins, and brassinosteroids, that have been thoroughly described to regulate plant development and growth, have recently emerged as key regulators of plant immunity. Plant hormones interact in complex networks to balance the response to developmental and environmental cues and thus limiting defense-associated fitness costs. The molecular mechanisms that govern these hormonal networks are largely unknown. Moreover, hormone signaling pathways are targeted by pathogens to disturb and evade plant defense responses. In this review, we address novel insights on the regulatory roles of the ABA, SA, and auxin in plant resistance to pathogens and we describe the complex interactions among their signal transduction pathways. The strategies developed by pathogens to evade hormone-mediated defensive responses are also described. Based on these data we discuss how hormone signaling could be manipulated to improve the resistance of crops to pathogens. PMID:23745126

  1. Escherichia coli O157:H7 induces stronger plant immunity than Salmonella enterica Typhimurium SL1344.

    PubMed

    Roy, Debanjana; Panchal, Shweta; Rosa, Bruce A; Melotto, Maeli

    2013-04-01

    Consumption of fresh produce contaminated with bacterial human pathogens has resulted in various, sometimes deadly, disease outbreaks. In this study, we assessed plant defense responses induced by the fully pathogenic bacteria Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium SL1344 in both Arabidopsis thaliana and lettuce (Lactuca sativa). Unlike SL1344, O157:H7 induced strong plant immunity at both pre-invasion and post-invasion steps of infection. For instance, O157:H7 triggered stomatal closure even under high relative humidity, an environmental condition that generally weakens plant defenses against bacteria in the field and laboratory conditions. SL1344 instead induced a transient stomatal immunity. We also observed that PR1 gene expression was significantly higher in Arabidopsis leaves infected with O157:H7 compared with SL1344. These results suggest that plants may recognize and respond to some human pathogens more effectively than others. Furthermore, stomatal immunity can diminish the penetration of human pathogens through the leaf epidermis, resulting in low bacterial titers in the plant apoplast and suggesting that additional control measures can be employed to prevent food contamination. The understanding of how plant responses can diminish bacterial contamination is paramount in preventing outbreaks and improving the safety of food supplies.

  2. NIK1, a host factor specialized in antiviral defense or a novel general regulator of plant immunity?

    PubMed

    Machado, Joao P B; Brustolini, Otavio J B; Mendes, Giselle C; Santos, Anésia A; Fontes, Elizabeth P B

    2015-11-01

    NIK1 is a receptor-like kinase involved in plant antiviral immunity. Although NIK1 is structurally similar to the plant immune factor BAK1, which is a key regulator in plant immunity to bacterial pathogens, the NIK1-mediated defenses do not resemble BAK1 signaling cascades. The underlying mechanism for NIK1 antiviral immunity has recently been uncovered. NIK1 activation mediates the translocation of RPL10 to the nucleus, where it interacts with LIMYB to fully down-regulate translational machinery genes, resulting in translation inhibition of host and viral mRNAs and enhanced tolerance to begomovirus. Therefore, the NIK1 antiviral immunity response culminates in global translation suppression, which represents a new paradigm for plant antiviral defenses. Interestingly, transcriptomic analyses in nik1 mutant suggest that NIK1 may suppress antibacterial immune responses, indicating a possible opposite effect of NIK1 in bacterial and viral infections.

  3. Structural basis of pathogen recognition by an integrated HMA domain in a plant NLR immune receptor

    PubMed Central

    Maqbool, A; Saitoh, H; Franceschetti, M; Stevenson, CEM; Uemura, A; Kanzaki, H; Kamoun, S; Terauchi, R; Banfield, MJ

    2015-01-01

    Plants have evolved intracellular immune receptors to detect pathogen proteins known as effectors. How these immune receptors detect effectors remains poorly understood. Here we describe the structural basis for direct recognition of AVR-Pik, an effector from the rice blast pathogen, by the rice intracellular NLR immune receptor Pik. AVR-PikD binds a dimer of the Pikp-1 HMA integrated domain with nanomolar affinity. The crystal structure of the Pikp-HMA/AVR-PikD complex enabled design of mutations to alter protein interaction in yeast and in vitro, and perturb effector-mediated response both in a rice cultivar containing Pikp and upon expression of AVR-PikD and Pikp in the model plant Nicotiana benthamiana. These data reveal the molecular details of a recognition event, mediated by a novel integrated domain in an NLR, which initiates a plant immune response and resistance to rice blast disease. Such studies underpin novel opportunities for engineering disease resistance to plant pathogens in staple food crops. DOI: http://dx.doi.org/10.7554/eLife.08709.001 PMID:26304198

  4. Light acclimation, retrograde signalling, cell death and immune defences in plants.

    PubMed

    Karpiński, Stanisław; Szechyńska-Hebda, Magdalena; Wituszyńska, Weronika; Burdiak, Paweł

    2013-04-01

    This review confronts the classical view of plant immune defence and light acclimation with recently published data. Earlier findings have linked plant immune defences to nucleotide-binding site leucine-rich repeat (NBS-LRR)-dependent recognition of pathogen effectors and to the role of plasma membrane-localized NADPH-dependent oxidoreductase (AtRbohD), reactive oxygen species (ROS) and salicylic acid (SA). However, recent results suggest that plant immune defence also depends on the absorption of excessive light energy and photorespiration. Rapid changes in light intensity and quality often cause the absorption of energy, which is in excess of that required for photosynthesis. Such excessive light energy is considered to be a factor triggering photoinhibition and disturbance in ROS/hormonal homeostasis, which leads to cell death in foliar tissues. We highlight here the tight crosstalk between ROS- and SA-dependent pathways leading to light acclimation, and defence responses leading to pathogen resistance. We also show that LESION SIMULATING DISEASE 1 (LSD1) regulates and integrates these processes. Moreover, we discuss the role of plastid-nucleus signal transduction, photorespiration, photoelectrochemical signalling and 'light memory' in the regulation of acclimation and immune defence responses. All of these results suggest that plants have evolved a genetic system that simultaneously regulates systemic acquired resistance (SAR), cell death and systemic acquired acclimation (SAA).

  5. Synthesis of the Caeliferins, elicitors of plant immune responses: accessing Lipophilic natural products via cross metathesis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We report a cross metathesis- (CM-) based syn-thesis of the caeliferins, a family of sulfooxy fatty acids that elicit plant immune responses. Unexpectedly, detailed NMR-spectroscopic and mass spectrometric analyses of CM reaction mixtures revealed extensive isomerization and homologation of starting...

  6. Scavenging iron: a novel mechanism of plant immunity activation by microbial siderophores.

    PubMed

    Aznar, Aude; Chen, Nicolas W G; Rigault, Martine; Riache, Nassima; Joseph, Delphine; Desmaële, Didier; Mouille, Grégory; Boutet, Stéphanie; Soubigou-Taconnat, Ludivine; Renou, Jean-Pierre; Thomine, Sébastien; Expert, Dominique; Dellagi, Alia

    2014-04-01

    Siderophores are specific ferric iron chelators synthesized by virtually all microorganisms in response to iron deficiency. We have previously shown that they promote infection by the phytopathogenic enterobacteria Dickeya dadantii and Erwinia amylovora. Siderophores also have the ability to activate plant immunity. We have used complete Arabidopsis transcriptome microarrays to investigate the global transcriptional modifications in roots and leaves of Arabidopsis (Arabidopsis thaliana) plants after leaf treatment with the siderophore deferrioxamine (DFO). Physiological relevance of these transcriptional modifications was validated experimentally. Immunity and heavy-metal homeostasis were the major processes affected by DFO. These two physiological responses could be activated by a synthetic iron chelator ethylenediamine-di(o-hydroxyphenylacetic) acid, indicating that siderophores eliciting activities rely on their strong iron-chelating capacity. DFO was able to protect Arabidopsis against the pathogenic bacterium Pseudomonas syringae pv tomato DC3000. Siderophore treatment caused local modifications of iron distribution in leaf cells visible by ferrocyanide and diaminobenzidine-H₂O₂ staining. Metal quantifications showed that DFO causes a transient iron and zinc uptake at the root level, which is presumably mediated by the metal transporter iron regulated transporter1 (IRT1). Defense gene expression and callose deposition in response to DFO were compromised in an irt1 mutant. Consistently, plant susceptibility to D. dadantii was increased in the irt1 mutant. Our work shows that iron scavenging is a unique mechanism of immunity activation in plants. It highlights the strong relationship between heavy-metal homeostasis and immunity. PMID:24501001

  7. Scavenging Iron: A Novel Mechanism of Plant Immunity Activation by Microbial Siderophores1[C][W

    PubMed Central

    Aznar, Aude; Chen, Nicolas W.G.; Rigault, Martine; Riache, Nassima; Joseph, Delphine; Desmaële, Didier; Mouille, Grégory; Boutet, Stéphanie; Soubigou-Taconnat, Ludivine; Renou, Jean-Pierre; Thomine, Sébastien; Expert, Dominique; Dellagi, Alia

    2014-01-01

    Siderophores are specific ferric iron chelators synthesized by virtually all microorganisms in response to iron deficiency. We have previously shown that they promote infection by the phytopathogenic enterobacteria Dickeya dadantii and Erwinia amylovora. Siderophores also have the ability to activate plant immunity. We have used complete Arabidopsis transcriptome microarrays to investigate the global transcriptional modifications in roots and leaves of Arabidopsis (Arabidopsis thaliana) plants after leaf treatment with the siderophore deferrioxamine (DFO). Physiological relevance of these transcriptional modifications was validated experimentally. Immunity and heavy-metal homeostasis were the major processes affected by DFO. These two physiological responses could be activated by a synthetic iron chelator ethylenediamine-di(o-hydroxyphenylacetic) acid, indicating that siderophores eliciting activities rely on their strong iron-chelating capacity. DFO was able to protect Arabidopsis against the pathogenic bacterium Pseudomonas syringae pv tomato DC3000. Siderophore treatment caused local modifications of iron distribution in leaf cells visible by ferrocyanide and diaminobenzidine-H2O2 staining. Metal quantifications showed that DFO causes a transient iron and zinc uptake at the root level, which is presumably mediated by the metal transporter iron regulated transporter1 (IRT1). Defense gene expression and callose deposition in response to DFO were compromised in an irt1 mutant. Consistently, plant susceptibility to D. dadantii was increased in the irt1 mutant. Our work shows that iron scavenging is a unique mechanism of immunity activation in plants. It highlights the strong relationship between heavy-metal homeostasis and immunity. PMID:24501001

  8. Active oxygen species as mediators of plant immunity: three case studies.

    PubMed

    Sandermann, H

    2000-08-01

    A burst of active oxygen species (AOS) is known to be involved in local cell death as part of plant defence against pathogens. It is, however, under dispute to what extent AOS can induce pathogen resistance and immunity throughout the plant. Three experimental strategies that reveal a primary role for AOS and a surprisingly low chemical and spatial specificity are now described for tobacco and Arabidopsis thaliana plants. Ozone is a gaseous AOS that was applied to non-transgenic plants. Hydrogen peroxide or singlet oxygen are AOS that were induced by high-light treatment of transgenic plants that contained antisense constructs inhibiting catalase activity or chlorophyll biosynthetic enzymes. In all cases, activated oxygen species, cellular lesions, ethylene and salicylic acid, and components of major plant defence systems (systemic acquired resistance, hypersensitive response) were induced, as was resistance towards pathogens (tobacco mosaic virus, Pseudomonas syringae or Peronospora parasitica). It is concluded that active oxygen species can act as mediators of plant immunity so that new non-pesticidal plant protection strategies could be developed.

  9. Cross-Regulation between N Metabolism and Nitric Oxide (NO) Signaling during Plant Immunity

    PubMed Central

    Thalineau, Elise; Truong, Hoai-Nam; Berger, Antoine; Fournier, Carine; Boscari, Alexandre; Wendehenne, David; Jeandroz, Sylvain

    2016-01-01

    Plants are sessile organisms that have evolved a complex immune system which helps them cope with pathogen attacks. However, the capacity of a plant to mobilize different defense responses is strongly affected by its physiological status. Nitrogen (N) is a major nutrient that can play an important role in plant immunity by increasing or decreasing plant resistance to pathogens. Although no general rule can be drawn about the effect of N availability and quality on the fate of plant/pathogen interactions, plants’ capacity to acquire, assimilate, allocate N, and maintain amino acid homeostasis appears to partly mediate the effects of N on plant defense. Nitric oxide (NO), one of the products of N metabolism, plays an important role in plant immunity signaling. NO is generated in part through Nitrate Reductase (NR), a key enzyme involved in nitrate assimilation, and its production depends on levels of nitrate/nitrite, NR substrate/product, as well as on L-arginine and polyamine levels. Cross-regulation between NO signaling and N supply/metabolism has been evidenced. NO production can be affected by N supply, and conversely NO appears to regulate nitrate transport and assimilation. Based on this knowledge, we hypothesized that N availability partly controls plant resistance to pathogens by controlling NO homeostasis. Using the Medicago truncatula/Aphanomyces euteiches pathosystem, we showed that NO homeostasis is important for resistance to this oomycete and that N availability impacts NO homeostasis by affecting S-nitrosothiol (SNO) levels and S-nitrosoglutathione reductase activity in roots. These results could therefore explain the increased resistance we noted in N-deprived as compared to N-replete M. truncatula seedlings. They open onto new perspectives for the studies of N/plant defense interactions. PMID:27092169

  10. Construction and comparison of gene co-expression networks shows complex plant immune responses

    PubMed Central

    López, Camilo; López-Kleine, Liliana

    2014-01-01

    Gene co-expression networks (GCNs) are graphic representations that depict the coordinated transcription of genes in response to certain stimuli. GCNs provide functional annotations of genes whose function is unknown and are further used in studies of translational functional genomics among species. In this work, a methodology for the reconstruction and comparison of GCNs is presented. This approach was applied using gene expression data that were obtained from immunity experiments in Arabidopsis thaliana, rice, soybean, tomato and cassava. After the evaluation of diverse similarity metrics for the GCN reconstruction, we recommended the mutual information coefficient measurement and a clustering coefficient-based method for similarity threshold selection. To compare GCNs, we proposed a multivariate approach based on the Principal Component Analysis (PCA). Branches of plant immunity that were exemplified by each experiment were analyzed in conjunction with the PCA results, suggesting both the robustness and the dynamic nature of the cellular responses. The dynamic of molecular plant responses produced networks with different characteristics that are differentiable using our methodology. The comparison of GCNs from plant pathosystems, showed that in response to similar pathogens plants could activate conserved signaling pathways. The results confirmed that the closeness of GCNs projected on the principal component space is an indicative of similarity among GCNs. This also can be used to understand global patterns of events triggered during plant immune responses. PMID:25320678

  11. Heat Shock Proteins: A Review of the Molecular Chaperones for Plant Immunity

    PubMed Central

    Park, Chang-Jin; Seo, Young-Su

    2015-01-01

    As sessile organisms, plants are exposed to persistently changing stresses and have to be able to interpret and respond to them. The stresses, drought, salinity, chemicals, cold and hot temperatures, and various pathogen attacks have interconnected effects on plants, resulting in the disruption of protein homeostasis. Maintenance of proteins in their functional native conformations and preventing aggregation of non-native proteins are important for cell survival under stress. Heat shock proteins (HSPs) functioning as molecular chaperones are the key components responsible for protein folding, assembly, translocation, and degradation under stress conditions and in many normal cellular processes. Plants respond to pathogen invasion using two different innate immune responses mediated by pattern recognition receptors (PRRs) or resistance (R) proteins. HSPs play an indispensable role as molecular chaperones in the quality control of plasma membrane-resident PRRs and intracellular R proteins against potential invaders. Here, we specifically discuss the functional involvement of cytosolic and endoplasmic reticulum (ER) HSPs/chaperones in plant immunity to obtain an integrated understanding of the immune responses in plant cells. PMID:26676169

  12. Chitosan nanoparticles: A positive modulator of innate immune responses in plants.

    PubMed

    Chandra, Swarnendu; Chakraborty, Nilanjan; Dasgupta, Adhiraj; Sarkar, Joy; Panda, Koustubh; Acharya, Krishnendu

    2015-01-01

    The immunomodulatory role of the natural biopolymer, chitosan, has already been demonstrated in plants, whilst its nanoparticles have only been examined for biomedical applications. In our present study, we have investigated the possible ability and mechanism of chitosan nanoparticles (CNP) to induce and augment immune responses in plants. CNP-treatment of leaves produced significant improvement in the plant's innate immune response through induction of defense enzyme activity, upregulation of defense related genes including that of several antioxidant enzymes as well as elevation of the levels of total phenolics. It is also possible that the extracellular localization of CNP may also play a role in the observed upregulation of defense response in plants. Nitric oxide (NO), an important signaling molecule in plant defense, was also observed to increase following CNP treatment. However, such CNP-mediated immuno-stimulation was significantly mitigated when NO production was inhibited, indicating a possible role of NO in such immune induction. Taken together, our results suggest that CNP may be used as a more effective phytosanitary or disease control agent compared to natural chitosan for sustainable organic cultivation. PMID:26471771

  13. Chitosan nanoparticles: A positive modulator of innate immune responses in plants.

    PubMed

    Chandra, Swarnendu; Chakraborty, Nilanjan; Dasgupta, Adhiraj; Sarkar, Joy; Panda, Koustubh; Acharya, Krishnendu

    2015-10-16

    The immunomodulatory role of the natural biopolymer, chitosan, has already been demonstrated in plants, whilst its nanoparticles have only been examined for biomedical applications. In our present study, we have investigated the possible ability and mechanism of chitosan nanoparticles (CNP) to induce and augment immune responses in plants. CNP-treatment of leaves produced significant improvement in the plant's innate immune response through induction of defense enzyme activity, upregulation of defense related genes including that of several antioxidant enzymes as well as elevation of the levels of total phenolics. It is also possible that the extracellular localization of CNP may also play a role in the observed upregulation of defense response in plants. Nitric oxide (NO), an important signaling molecule in plant defense, was also observed to increase following CNP treatment. However, such CNP-mediated immuno-stimulation was significantly mitigated when NO production was inhibited, indicating a possible role of NO in such immune induction. Taken together, our results suggest that CNP may be used as a more effective phytosanitary or disease control agent compared to natural chitosan for sustainable organic cultivation.

  14. Plant immunity triggered by engineered in vivo release of oligogalacturonides, damage-associated molecular patterns.

    PubMed

    Benedetti, Manuel; Pontiggia, Daniela; Raggi, Sara; Cheng, Zhenyu; Scaloni, Flavio; Ferrari, Simone; Ausubel, Frederick M; Cervone, Felice; De Lorenzo, Giulia

    2015-04-28

    Oligogalacturonides (OGs) are fragments of pectin that activate plant innate immunity by functioning as damage-associated molecular patterns (DAMPs). We set out to test the hypothesis that OGs are generated in planta by partial inhibition of pathogen-encoded polygalacturonases (PGs). A gene encoding a fungal PG was fused with a gene encoding a plant polygalacturonase-inhibiting protein (PGIP) and expressed in transgenic Arabidopsis plants. We show that expression of the PGIP-PG chimera results in the in vivo production of OGs that can be detected by mass spectrometric analysis. Transgenic plants expressing the chimera under control of a pathogen-inducible promoter are more resistant to the phytopathogens Botrytis cinerea, Pectobacterium carotovorum, and Pseudomonas syringae. These data provide strong evidence for the hypothesis that OGs released in vivo act as a DAMP signal to trigger plant immunity and suggest that controlled release of these molecules upon infection may be a valuable tool to protect plants against infectious diseases. On the other hand, elevated levels of expression of the chimera cause the accumulation of salicylic acid, reduced growth, and eventually lead to plant death, consistent with the current notion that trade-off occurs between growth and defense.

  15. Plant immunity triggered by engineered in vivo release of oligogalacturonides, damage-associated molecular patterns

    PubMed Central

    Benedetti, Manuel; Pontiggia, Daniela; Raggi, Sara; Cheng, Zhenyu; Scaloni, Flavio; Ferrari, Simone; Ausubel, Frederick M.; Cervone, Felice; De Lorenzo, Giulia

    2015-01-01

    Oligogalacturonides (OGs) are fragments of pectin that activate plant innate immunity by functioning as damage-associated molecular patterns (DAMPs). We set out to test the hypothesis that OGs are generated in planta by partial inhibition of pathogen-encoded polygalacturonases (PGs). A gene encoding a fungal PG was fused with a gene encoding a plant polygalacturonase-inhibiting protein (PGIP) and expressed in transgenic Arabidopsis plants. We show that expression of the PGIP–PG chimera results in the in vivo production of OGs that can be detected by mass spectrometric analysis. Transgenic plants expressing the chimera under control of a pathogen-inducible promoter are more resistant to the phytopathogens Botrytis cinerea, Pectobacterium carotovorum, and Pseudomonas syringae. These data provide strong evidence for the hypothesis that OGs released in vivo act as a DAMP signal to trigger plant immunity and suggest that controlled release of these molecules upon infection may be a valuable tool to protect plants against infectious diseases. On the other hand, elevated levels of expression of the chimera cause the accumulation of salicylic acid, reduced growth, and eventually lead to plant death, consistent with the current notion that trade-off occurs between growth and defense. PMID:25870275

  16. Immunization.

    ERIC Educational Resources Information Center

    Guerin, Nicole; And Others

    1986-01-01

    Contents of this double journal issue concern immunization and primary health care of children. The issue decribes vaccine storage and sterilization techniques, giving particular emphasis to the role of the cold chain, i.e., the maintenance of a specific temperature range to assure potency of vaccines as they are moved from a national storage…

  17. Assessment of Some Immune Parameters in Occupationally Exposed Nuclear Power Plant Workers

    PubMed Central

    Penkova, Kalina Ivanova; Rupova, Ivanka Tankova; Panova, Delyana Yonkova; Djounova, Jana Nikolaeva

    2015-01-01

    A 10-year survey of immune status of nuclear power plant (NPP) workers was assessed by cellular and humoral immune parameters. The cumulative doses of NPP workers were in the range of 0.06 to 766.36 mSv. The results did not show significant deviations in the studied parameters of cellular and humoral immunity, but a tendency of elevated values in CD3+4+ helper inducers cells, especially its CD4+62L+ subpopulation, regulatory CD4+25+ cells, CD8+28+ cytotoxic subpopulation, and immunoglobulin M, was established. The observed trend of the above-mentioned parameters could be interpreted by assumption that while the adaptation processes are dominated with low prevalence of T-helper (Th) 1 immune response to cumulative doses less than 100 mSv, a switch to Th-2 response occurred at doses above 100 mSv. The impact of a number of other confounding factors on the immune system does not allow definitive conclusions about the direct radiation-induced changes in immune parameters. PMID:26740807

  18. Chitosan nanoparticles: A positive modulator of innate immune responses in plants

    PubMed Central

    Chandra, Swarnendu; Chakraborty, Nilanjan; Dasgupta, Adhiraj; Sarkar, Joy; Panda, Koustubh; Acharya, Krishnendu

    2015-01-01

    The immunomodulatory role of the natural biopolymer, chitosan, has already been demonstrated in plants, whilst its nanoparticles have only been examined for biomedical applications. In our present study, we have investigated the possible ability and mechanism of chitosan nanoparticles (CNP) to induce and augment immune responses in plants. CNP-treatment of leaves produced significant improvement in the plant’s innate immune response through induction of defense enzyme activity, upregulation of defense related genes including that of several antioxidant enzymes as well as elevation of the levels of total phenolics. It is also possible that the extracellular localization of CNP may also play a role in the observed upregulation of defense response in plants. Nitric oxide (NO), an important signaling molecule in plant defense, was also observed to increase following CNP treatment. However, such CNP-mediated immuno-stimulation was significantly mitigated when NO production was inhibited, indicating a possible role of NO in such immune induction. Taken together, our results suggest that CNP may be used as a more effective phytosanitary or disease control agent compared to natural chitosan for sustainable organic cultivation. PMID:26471771

  19. Chitosan nanoparticles: A positive modulator of innate immune responses in plants

    NASA Astrophysics Data System (ADS)

    Chandra, Swarnendu; Chakraborty, Nilanjan; Dasgupta, Adhiraj; Sarkar, Joy; Panda, Koustubh; Acharya, Krishnendu

    2015-10-01

    The immunomodulatory role of the natural biopolymer, chitosan, has already been demonstrated in plants, whilst its nanoparticles have only been examined for biomedical applications. In our present study, we have investigated the possible ability and mechanism of chitosan nanoparticles (CNP) to induce and augment immune responses in plants. CNP-treatment of leaves produced significant improvement in the plant’s innate immune response through induction of defense enzyme activity, upregulation of defense related genes including that of several antioxidant enzymes as well as elevation of the levels of total phenolics. It is also possible that the extracellular localization of CNP may also play a role in the observed upregulation of defense response in plants. Nitric oxide (NO), an important signaling molecule in plant defense, was also observed to increase following CNP treatment. However, such CNP-mediated immuno-stimulation was significantly mitigated when NO production was inhibited, indicating a possible role of NO in such immune induction. Taken together, our results suggest that CNP may be used as a more effective phytosanitary or disease control agent compared to natural chitosan for sustainable organic cultivation.

  20. Ternary WD40 Repeat-Containing Protein Complexes: Evolution, Composition and Roles in Plant Immunity

    PubMed Central

    Miller, Jimi C.; Chezem, William R.; Clay, Nicole K.

    2016-01-01

    Plants, like mammals, rely on their innate immune system to perceive and discriminate among the majority of their microbial pathogens. Unlike mammals, plants respond to this molecular dialog by unleashing a complex chemical arsenal of defense metabolites to resist or evade pathogen infection. In basal or non-host resistance, plants utilize signal transduction pathways to detect “non-self,” “damaged-self,” and “altered-self”- associated molecular patterns and translate these “danger” signals into largely inducible chemical defenses. The WD40 repeat (WDR)-containing proteins Gβ and TTG1 are constituents of two independent ternary protein complexes functioning at opposite ends of a plant immune signaling pathway. They are also encoded by single-copy genes that are ubiquitous in higher plants, implying the limited diversity and functional conservation of their respective complexes. In this review, we summarize what is currently known about the evolutionary history of these WDR-containing ternary complexes, their repertoire and combinatorial interactions, and their downstream effectors and pathways in plant defense. PMID:26779203

  1. Connecting growth and defense: the emerging roles of brassinosteroids and gibberellins in plant innate immunity.

    PubMed

    De Bruyne, Lieselotte; Höfte, Monica; De Vleesschauwer, David

    2014-06-01

    Brassinosteroids (BRs) and gibberellins (GAs) are two groups of phytohormones that regulate many common developmental processes throughout the plant life cycle. Fueled by large-scale 'omics' technologies and the burgeoning field of plant computational biology, the past few years have witnessed paradigm-shifting advances in our understanding of how BRs and GA are perceived and their signals transduced. Accumulating evidence also implicates BR and GA in the coordination and integration of plant immune responses. Similarly to other growth regulators, BR and GA play ambiguous roles in molding pathological outcomes, the effects of which may depend not only on the pathogen's lifestyle and infection strategy, but also on specialized features of each interaction. Analysis of the underpinning molecular mechanisms points to a crucial role of GA-inhibiting DELLA proteins and the BR-regulated transcription factor BZR1. Acting at the interface of developmental and defense signaling, these proteins likely serve as central hubs for pathway crosstalk and signal integration, allowing appropriate modulation of plant growth and defense in response to various stimuli. In this review, we outline the latest discoveries dealing with BR and GA modulation of plant innate immunity and highlight interactions between BR and GA signaling, plant defense, and microbial virulence.

  2. Plant sterols and sterolins: a review of their immune-modulating properties.

    PubMed

    Bouic, P J; Lamprecht, J H

    1999-06-01

    Beta-sitosterol (BSS) and its glycoside (BSSG) are sterol molecules which are synthesized by plants. When humans eat plant foods phytosterols are ingested, and are found in the serum and tissues of healthy individuals, but at concentrations orders of magnitude lower than endogenous cholesterol. Epidemiological studies have correlated a reduced risk of numerous diseases with a diet high in fruits and vegetables, and have concluded that specific molecules, including b-carotene, tocopherols, vitamin C, and flavonoids, confer some of this protective benefit. However, these epidemiologic studies have not examined the potential effect that phytosterols ingested with fruits and vegetables might have on disease risk reduction. In animals, BSS and BSSG have been shown to exhibit anti-inflammatory, anti-neoplastic, anti-pyretic, and immune-modulating activity. A proprietary BSS:BSSG mixture has demonstrated promising results in a number of studies, including in vitro studies, animal models, and human clinical trials. This phytosterol complex seems to target specific T-helper lymphocytes, the Th1 and Th2 cells, helping normalize their functioning and resulting in improved T-lymphocyte and natural killer cell activity. A dampening effect on overactive antibody responses has also been seen, as well as normalization of the DHEA:cortisol ratio. The re-establishment of these immune parameters may be of help in numerous disease processes relating to chronic immune-mediated abnormalities, including chronic viral infections, tuberculosis, rheumatoid arthritis, allergies, cancer, and auto-immune diseases. PMID:10383481

  3. Immunization with Potato Plants Expressing VP60 Protein Protects against Rabbit Hemorrhagic Disease Virus

    PubMed Central

    Castañón, S.; Marín, M. S.; Martín-Alonso, J. M.; Boga, J. A.; Casais, R.; Humara, J. M.; Ordás, R. J.; Parra, F.

    1999-01-01

    The major structural protein VP60 of rabbit hemorrhagic disease virus (RHDV) has been produced in transgenic potato plants under the control of a cauliflower mosaic virus 35S promoter or a modified 35S promoter that included two copies of a strong transcriptional enhancer. Both types of promoters allowed the production of specific mRNAs and detectable levels of recombinant VP60, which were higher for the constructs carrying the modified 35S promoter. Rabbits immunized with leaf extracts from plants carrying this modified 35S promoter showed high anti-VP60 antibody titers and were fully protected against the hemorrhagic disease. PMID:10196345

  4. Immune modulation enables a specialist insect to benefit from antibacterial withanolides in its host plant

    PubMed Central

    Barthel, Andrea; Vogel, Heiko; Pauchet, Yannick; Pauls, Gerhard; Kunert, Grit; Groot, Astrid T.; Boland, Wilhelm; Heckel, David G.; Heidel-Fischer, Hanna M.

    2016-01-01

    The development of novel plant chemical defenses and counter adaptations by herbivorous insect could continually drive speciation, producing more insect specialists than generalists. One approach to test this hypothesis is to compare closely related generalist and specialist species to reveal the associated costs and benefits of these different adaptive strategies. We use the specialized moth Heliothis subflexa, which feeds exclusively on plants in the genus Physalis, and its close generalist relative H. virescens. Specialization on Physalis plants necessitates the ability to tolerate withanolides, the secondary metabolites of Physalis species that are known to have feeding deterrent and immune inhibiting properties for other insects. Here we find that only H. subflexa benefits from the antibacterial properties of withanolides, and thereby gains a higher tolerance of the pathogen Bacillus thuringiensis. We argue that the specialization in H. subflexa has been guided to a large extent by a unique role of plant chemistry on ecological immunology. PMID:27561781

  5. Immune modulation enables a specialist insect to benefit from antibacterial withanolides in its host plant.

    PubMed

    Barthel, Andrea; Vogel, Heiko; Pauchet, Yannick; Pauls, Gerhard; Kunert, Grit; Groot, Astrid T; Boland, Wilhelm; Heckel, David G; Heidel-Fischer, Hanna M

    2016-01-01

    The development of novel plant chemical defenses and counter adaptations by herbivorous insect could continually drive speciation, producing more insect specialists than generalists. One approach to test this hypothesis is to compare closely related generalist and specialist species to reveal the associated costs and benefits of these different adaptive strategies. We use the specialized moth Heliothis subflexa, which feeds exclusively on plants in the genus Physalis, and its close generalist relative H. virescens. Specialization on Physalis plants necessitates the ability to tolerate withanolides, the secondary metabolites of Physalis species that are known to have feeding deterrent and immune inhibiting properties for other insects. Here we find that only H. subflexa benefits from the antibacterial properties of withanolides, and thereby gains a higher tolerance of the pathogen Bacillus thuringiensis. We argue that the specialization in H. subflexa has been guided to a large extent by a unique role of plant chemistry on ecological immunology. PMID:27561781

  6. Plant Hormone Salicylic Acid Produced by a Malaria Parasite Controls Host Immunity and Cerebral Malaria Outcome

    PubMed Central

    Matsubara, Ryuma; Aonuma, Hiroka; Kojima, Mikiko; Tahara, Michiru; Andrabi, Syed Bilal Ahmad; Sakakibara, Hitoshi; Nagamune, Kisaburo

    2015-01-01

    The apicomplexan parasite Toxoplasma gondii produces the plant hormone abscisic acid, but it is unclear if phytohormones are produced by the malaria parasite Plasmodium spp., the most important parasite of this phylum. Here, we report detection of salicylic acid, an immune-related phytohormone of land plants, in P. berghei ANKA and T. gondii cell lysates. However, addition of salicylic acid to P. falciparum and T. gondii culture had no effect. We transfected P. falciparum 3D7 with the nahG gene, which encodes a salicylic acid-degrading enzyme isolated from plant-infecting Pseudomonas sp., and established a salicylic acid-deficient mutant. The mutant had a significantly decreased concentration of parasite-synthesized prostaglandin E2, which potentially modulates host immunity as an adaptive evolution of Plasmodium spp. To investigate the function of salicylic acid and prostaglandin E2 on host immunity, we established P. berghei ANKA mutants expressing nahG. C57BL/6 mice infected with nahG transfectants developed enhanced cerebral malaria, as assessed by Evans blue leakage and brain histological observation. The nahG-transfectant also significantly increased the mortality rate of mice. Prostaglandin E2 reduced the brain symptoms by induction of T helper-2 cytokines. As expected, T helper-1 cytokines including interferon-γ and interleukin-2 were significantly elevated by infection with the nahG transfectant. Thus, salicylic acid of Plasmodium spp. may be a new pathogenic factor of this threatening parasite and may modulate immune function via parasite-produced prostaglandin E2. PMID:26466097

  7. Plant Hormone Salicylic Acid Produced by a Malaria Parasite Controls Host Immunity and Cerebral Malaria Outcome.

    PubMed

    Matsubara, Ryuma; Aonuma, Hiroka; Kojima, Mikiko; Tahara, Michiru; Andrabi, Syed Bilal Ahmad; Sakakibara, Hitoshi; Nagamune, Kisaburo

    2015-01-01

    The apicomplexan parasite Toxoplasma gondii produces the plant hormone abscisic acid, but it is unclear if phytohormones are produced by the malaria parasite Plasmodium spp., the most important parasite of this phylum. Here, we report detection of salicylic acid, an immune-related phytohormone of land plants, in P. berghei ANKA and T. gondii cell lysates. However, addition of salicylic acid to P. falciparum and T. gondii culture had no effect. We transfected P. falciparum 3D7 with the nahG gene, which encodes a salicylic acid-degrading enzyme isolated from plant-infecting Pseudomonas sp., and established a salicylic acid-deficient mutant. The mutant had a significantly decreased concentration of parasite-synthesized prostaglandin E2, which potentially modulates host immunity as an adaptive evolution of Plasmodium spp. To investigate the function of salicylic acid and prostaglandin E2 on host immunity, we established P. berghei ANKA mutants expressing nahG. C57BL/6 mice infected with nahG transfectants developed enhanced cerebral malaria, as assessed by Evans blue leakage and brain histological observation. The nahG-transfectant also significantly increased the mortality rate of mice. Prostaglandin E2 reduced the brain symptoms by induction of T helper-2 cytokines. As expected, T helper-1 cytokines including interferon-γ and interleukin-2 were significantly elevated by infection with the nahG transfectant. Thus, salicylic acid of Plasmodium spp. may be a new pathogenic factor of this threatening parasite and may modulate immune function via parasite-produced prostaglandin E2. PMID:26466097

  8. Plant Hormone Salicylic Acid Produced by a Malaria Parasite Controls Host Immunity and Cerebral Malaria Outcome.

    PubMed

    Matsubara, Ryuma; Aonuma, Hiroka; Kojima, Mikiko; Tahara, Michiru; Andrabi, Syed Bilal Ahmad; Sakakibara, Hitoshi; Nagamune, Kisaburo

    2015-01-01

    The apicomplexan parasite Toxoplasma gondii produces the plant hormone abscisic acid, but it is unclear if phytohormones are produced by the malaria parasite Plasmodium spp., the most important parasite of this phylum. Here, we report detection of salicylic acid, an immune-related phytohormone of land plants, in P. berghei ANKA and T. gondii cell lysates. However, addition of salicylic acid to P. falciparum and T. gondii culture had no effect. We transfected P. falciparum 3D7 with the nahG gene, which encodes a salicylic acid-degrading enzyme isolated from plant-infecting Pseudomonas sp., and established a salicylic acid-deficient mutant. The mutant had a significantly decreased concentration of parasite-synthesized prostaglandin E2, which potentially modulates host immunity as an adaptive evolution of Plasmodium spp. To investigate the function of salicylic acid and prostaglandin E2 on host immunity, we established P. berghei ANKA mutants expressing nahG. C57BL/6 mice infected with nahG transfectants developed enhanced cerebral malaria, as assessed by Evans blue leakage and brain histological observation. The nahG-transfectant also significantly increased the mortality rate of mice. Prostaglandin E2 reduced the brain symptoms by induction of T helper-2 cytokines. As expected, T helper-1 cytokines including interferon-γ and interleukin-2 were significantly elevated by infection with the nahG transfectant. Thus, salicylic acid of Plasmodium spp. may be a new pathogenic factor of this threatening parasite and may modulate immune function via parasite-produced prostaglandin E2.

  9. Next-Generation Genetics in Plants: Evolutionary Trade-off, Immunity and Speciation (2010 JGI User Meeting)

    ScienceCinema

    Wiegel, Detlef

    2016-07-12

    Detlef Wiegel from the Max Planck Institute for Developmental Biology on "Next-generation genetics in plants: Evolutionary tradeoffs, immunity and speciation" on March 25, 2010 at the 5th Annual DOE JGI User Meeting

  10. Next-Generation Genetics in Plants: Evolutionary Trade-off, Immunity and Speciation (2010 JGI User Meeting)

    SciTech Connect

    Wiegel, Detlef

    2010-03-25

    Detlef Wiegel from the Max Planck Institute for Developmental Biology on "Next-generation genetics in plants: Evolutionary tradeoffs, immunity and speciation" on March 25, 2010 at the 5th Annual DOE JGI User Meeting

  11. Chemical genetics reveals negative regulation of abscisic acid signaling by a plant immune response pathway.

    PubMed

    Kim, Tae-Houn; Hauser, Felix; Ha, Tracy; Xue, Shaowu; Böhmer, Maik; Nishimura, Noriyuki; Munemasa, Shintaro; Hubbard, Katharine; Peine, Nora; Lee, Byeong-Ha; Lee, Stephen; Robert, Nadia; Parker, Jane E; Schroeder, Julian I

    2011-06-01

    Coordinated regulation of protection mechanisms against environmental abiotic stress and pathogen attack is essential for plant adaptation and survival. Initial abiotic stress can interfere with disease-resistance signaling [1-6]. Conversely, initial plant immune signaling may interrupt subsequent abscisic acid (ABA) signal transduction [7, 8]. However, the processes involved in this crosstalk between these signaling networks have not been determined. By screening a 9600-compound chemical library, we identified a small molecule [5-(3,4-dichlorophenyl)furan-2-yl]-piperidine-1-ylmethanethione (DFPM) that rapidly downregulates ABA-dependent gene expression and also inhibits ABA-induced stomatal closure. Transcriptome analyses show that DFPM also stimulates expression of plant defense-related genes. Major early regulators of pathogen-resistance responses, including EDS1, PAD4, RAR1, and SGT1b, are required for DFPM-and notably also for Pseudomonas-interference with ABA signal transduction, whereas salicylic acid, EDS16, and NPR1 are not necessary. Although DFPM does not interfere with early ABA perception by PYR/RCAR receptors or ABA activation of SnRK2 kinases, it disrupts cytosolic Ca(2+) signaling and downstream anion channel activation in a PAD4-dependent manner. Our findings provide evidence that activation of EDS1/PAD4-dependent plant immune responses rapidly disrupts ABA signal transduction and that this occurs at the level of Ca(2+) signaling, illuminating how the initial biotic stress pathway interferes with ABA signaling.

  12. A Vavilovian approach to discovering crop-associated microbes with potential to enhance plant immunity

    PubMed Central

    Hale, Iago L.; Broders, Kirk; Iriarte, Gloria

    2014-01-01

    Through active associations with a diverse community of largely non-pathogenic microbes, a plant may be thought of as possessing an “extended genotype,” an interactive cross-organismal genome with potential, exploitable implications for plant immunity. The successful enrichment of plant microbiomes with beneficial species has led to numerous commercial applications, and the hunt for new biocontrol organisms continues. Increasingly flexible and affordable sequencing technologies, supported by increasingly comprehensive taxonomic databases, make the characterization of non-model crop-associated microbiomes a widely accessible research method toward this end; and such studies are becoming more frequent. A summary of this emerging literature reveals, however, the need for a more systematic research lens in the face of what is already a metagenomics data deluge. Considering the processes and consequences of crop evolution and domestication, we assert that the judicious integration of in situ crop wild relatives into phytobiome research efforts presents a singularly powerful tool for separating signal from noise, thereby facilitating a more efficient means of identifying candidate plant-associated microbes with the potential for enhancing the immunity and fitness of crop species. PMID:25278956

  13. The Ustilago maydis effector Pep1 suppresses plant immunity by inhibition of host peroxidase activity.

    PubMed

    Hemetsberger, Christoph; Herrberger, Christian; Zechmann, Bernd; Hillmer, Morten; Doehlemann, Gunther

    2012-01-01

    The corn smut Ustilago maydis establishes a biotrophic interaction with its host plant maize. This interaction requires efficient suppression of plant immune responses, which is attributed to secreted effector proteins. Previously we identified Pep1 (Protein essential during penetration-1) as a secreted effector with an essential role for U. maydis virulence. pep1 deletion mutants induce strong defense responses leading to an early block in pathogenic development of the fungus. Using cytological and functional assays we show that Pep1 functions as an inhibitor of plant peroxidases. At sites of Δpep1 mutant penetrations, H₂O₂ strongly accumulated in the cell walls, coinciding with a transcriptional induction of the secreted maize peroxidase POX12. Pep1 protein effectively inhibited the peroxidase driven oxidative burst and thereby suppresses the early immune responses of maize. Moreover, Pep1 directly inhibits peroxidases in vitro in a concentration-dependent manner. Using fluorescence complementation assays, we observed a direct interaction of Pep1 and the maize peroxidase POX12 in vivo. Functional relevance of this interaction was demonstrated by partial complementation of the Δpep1 mutant defect by virus induced gene silencing of maize POX12. We conclude that Pep1 acts as a potent suppressor of early plant defenses by inhibition of peroxidase activity. Thus, it represents a novel strategy for establishing a biotrophic interaction.

  14. Plant Photosynthetic Responses During Insect Effector-Triggered Plant Susceptibility and Immunity.

    PubMed

    Gramig, Greta G; Harris, Marion O

    2015-06-01

    Gall-inducing insects are known for altering source-sink relationships within plants. Changes in photosynthesis may contribute to this phenomenon. We investigated photosynthetic responses in wheat [Triticum aestivum L. (Poaceae: Triticeae)] seedlings attacked by the Hessian fly [Mayetiola destructor (Say) (Diptera: Cecidomyiidae], which uses a salivary effector-based strategy to induce a gall nutritive tissue in susceptible plants. Resistant plants have surveillance systems mediated by products of Resistance (R) genes. Detection of a specific salivary effector triggers downstream responses that result in a resistance that kills neonate larvae. A 2 × 2 factorial design was used to study maximum leaf photosynthetic assimilation and stomatal conductance rates. The plant treatments were-resistant or susceptible wheat lines expressing or not expressing the H13 resistance gene. The insect treatments were-no attack (control) or attack by larvae killed by H13 gene-mediated resistance. Photosynthesis was measured for the second and third leaves of the seedling, the latter being the only leaf directly attacked by larvae. We predicted effector-based attack would trigger increases in photosynthetic rates in susceptible but not resistant plants. For susceptible plants, attack was associated with increases (relative to controls) in photosynthesis for the third but not the second leaf. For resistant plants, attack was associated with increases in photosynthesis for both the second and third leaves. Mechanisms underlying the increases appeared to differ. Resistant plants exhibited responses suggesting altered source-sink relationships. Susceptible plants exhibited responses suggesting a mechanism other than altered source-sink relationships, possibly changes in water relations that contributed to increased stomatal conductance.

  15. Brassinosteroids modulate the efficiency of plant immune responses to microbe-associated molecular patterns.

    PubMed

    Belkhadir, Youssef; Jaillais, Yvon; Epple, Petra; Balsemão-Pires, Emilia; Dangl, Jeffery L; Chory, Joanne

    2012-01-01

    Metazoans and plants use pattern recognition receptors (PRRs) to sense conserved microbial-associated molecular patterns (MAMPs) in the extracellular environment. In plants, the bacterial MAMPs flagellin and elongation factor Tu (EF-Tu) activate distinct, phylogenetically related cell surface pattern recognition receptors of the leucine-rich repeat receptor kinase (LRR-RK) family called FLS2 and EF-Tu receptor, respectively. BAK1 is an LRR-RK coreceptor for both FLS2 and EF-Tu receptor. BAK1 is also a coreceptor for the plant brassinosteroid (BR) receptor, the LRR-RK BRI1. Binding of BR to BRI1 primarily promotes cell elongation. Here, we tune the BR pathway response to establish how plant cells can generate functionally different cellular outputs in response to MAMPs and pathogens. We demonstrate that BR can act antagonistically or synergistically with responses to MAMPs. We further show that the synergistic activities of BRs on MAMP responses require BAK1. Our results highlight the importance of plant steroid homeostasis as a critical step in the establishment of plant immunity. We propose that tradeoffs associated with plasticity in the face of infection are layered atop plant steroid developmental programs.

  16. E3 ubiquitin-ligases and their target proteins during the regulation of plant innate immunity.

    PubMed

    Duplan, Vincent; Rivas, Susana

    2014-01-01

    Reversible protein ubiquitination plays a crucial role during the regulation of plant immune signaling. E3 ubiquitin (Ub)-ligase enzymes, which are classified into different families depending on their structural and functional features, confer the specificity of substrate and are the best characterized components of the ubiquitination cascade. E3 Ub-ligases of different families have been shown to be involved in all steps of plant immune responses. Indeed, they have been involved in the first steps of pathogen perception, as they appear to modulate perception of pathogen-associated molecular patterns by pattern-recognition receptors at the plasma membrane and to regulate the accumulation of nucleotide-binding leucine-rich repeat-type intracellular immune receptors. In addition, E3 Ub-ligase proteins are also involved in the regulation of the signaling responses downstream of pathogen perception through targeting vesicle trafficking components or nuclear transcription factors, for instance. Finally, we also discuss the case of microbial effector proteins that are able to target host E3 Ub-ligases, or to act themselves as E3 Ub-ligases, in their attempt to subvert the host proteasome to promote disease. PMID:24592270

  17. WRKY Transcription Factors Phosphorylated by MAPK Regulate a Plant Immune NADPH Oxidase in Nicotiana benthamiana.

    PubMed

    Adachi, Hiroaki; Nakano, Takaaki; Miyagawa, Noriko; Ishihama, Nobuaki; Yoshioka, Miki; Katou, Yuri; Yaeno, Takashi; Shirasu, Ken; Yoshioka, Hirofumi

    2015-09-01

    Pathogen attack sequentially confers pattern-triggered immunity (PTI) and effector-triggered immunity (ETI) after sensing of pathogen patterns and effectors by plant immune receptors, respectively. Reactive oxygen species (ROS) play pivotal roles in PTI and ETI as signaling molecules. Nicotiana benthamiana RBOHB, an NADPH oxidase, is responsible for both the transient PTI ROS burst and the robust ETI ROS burst. Here, we show that RBOHB transactivation mediated by MAPK contributes to R3a/AVR3a-triggered ETI (AVR3a-ETI) ROS burst. RBOHB is markedly induced during the ETI and INF1-triggered PTI (INF1-PTI), but not flg22-tiggered PTI (flg22-PTI). We found that the RBOHB promoter contains a functional W-box in the R3a/AVR3a and INF1 signal-responsive cis-element. Ectopic expression of four phospho-mimicking mutants of WRKY transcription factors, which are MAPK substrates, induced RBOHB, and yeast one-hybrid analysis indicated that these mutants bind to the cis-element. Chromatin immunoprecipitation assays indicated direct binding of the WRKY to the cis-element in plants. Silencing of multiple WRKY genes compromised the upregulation of RBOHB, resulting in impairment of AVR3a-ETI and INF1-PTI ROS bursts, but not the flg22-PTI ROS burst. These results suggest that the MAPK-WRKY pathway is required for AVR3a-ETI and INF1-PTI ROS bursts by activation of RBOHB. PMID:26373453

  18. The hypersensitive induced reaction and leucine-rich repeat proteins regulate plant cell death associated with disease and plant immunity.

    PubMed

    Choi, Hyong Woo; Kim, Young Jin; Hwang, Byung Kook

    2011-01-01

    Pathogen-induced programmed cell death (PCD) is intimately linked with disease resistance and susceptibility. However, the molecular components regulating PCD, including hypersensitive and susceptible cell death, are largely unknown in plants. In this study, we show that pathogen-induced Capsicum annuum hypersensitive induced reaction 1 (CaHIR1) and leucine-rich repeat 1 (CaLRR1) function as distinct plant PCD regulators in pepper plants during Xanthomonas campestris pv. vesicatoria infection. Confocal microscopy and protein gel blot analyses revealed that CaLRR1 and CaHIR1 localize to the extracellular matrix and plasma membrane (PM), respectively. Bimolecular fluorescent complementation and coimmunoprecipitation assays showed that the extracellular CaLRR1 specifically binds to the PM-located CaHIR1 in pepper leaves. Overexpression of CaHIR1 triggered pathogen-independent cell death in pepper and Nicotiana benthamiana plants but not in yeast cells. Virus-induced gene silencing (VIGS) of CaLRR1 and CaHIR1 distinctly strengthened and compromised hypersensitive and susceptible cell death in pepper plants, respectively. Endogenous salicylic acid levels and pathogenesis-related gene transcripts were elevated in CaHIR1-silenced plants. VIGS of NbLRR1 and NbHIR1, the N. benthamiana orthologs of CaLRR1 and CaHIR1, regulated Bax- and avrPto-/Pto-induced PCD. Taken together, these results suggest that leucine-rich repeat and hypersensitive induced reaction proteins may act as cell-death regulators associated with plant immunity and disease.

  19. Photosynthetic light reactions--an adjustable hub in basic production and plant immunity signaling.

    PubMed

    Kangasjärvi, Saijaliisa; Tikkanen, Mikko; Durian, Guido; Aro, Eva-Mari

    2014-08-01

    Photosynthetic efficiency is a key trait that influences the sustainable utilization of plants for energy and nutrition. By now, extensive research on photosynthetic processes has underscored important structural and functional relationships among photosynthetic thylakoid membrane protein complexes, and their roles in determining the productivity and stress resistance of plants. Photosystem II photoinhibition-repair cycle, for example, has arisen vital in protecting also Photosystem I against light-induced damage. Availability of highly sophisticated genetic, biochemical and biophysical tools has greatly expanded the catalog of components that carry out photoprotective functions in plants. On thylakoid membranes, these components encompass a network of overlapping systems that allow delicate regulation of linear and cyclic electron transfer pathways, balancing of excitation energy distribution between the two photosystems and dissipation of excess light energy in the antenna system as heat. An increasing number of reports indicate that the above mentioned mechanisms also mediate important functions in the regulation of biotic stress responses in plants. Particularly the handling of excitation energy in the light harvesting II antenna complexes appears central to plant immunity signaling. Comprehensive understanding of the underlying mechanisms and regulatory cross-talk, however, still remain elusive. This review highlights the current understanding of components that regulate the function of photosynthetic light reactions and directly or indirectly also modulate disease resistance in higher plants.

  20. Sweet scents from good bacteria: Case studies on bacterial volatile compounds for plant growth and immunity.

    PubMed

    Chung, Joon-hui; Song, Geun Cheol; Ryu, Choong-Min

    2016-04-01

    Beneficial bacteria produce diverse chemical compounds that affect the behavior of other organisms including plants. Bacterial volatile compounds (BVCs) contribute to triggering plant immunity and promoting plant growth. Previous studies investigated changes in plant physiology caused by in vitro application of the identified volatile compounds or the BVC-emitting bacteria. This review collates new information on BVC-mediated plant-bacteria airborne interactions, addresses unresolved questions about the biological relevance of BVCs, and summarizes data on recently identified BVCs that improve plant growth or protection. Recent explorations of bacterial metabolic engineering to alter BVC production using heterologous or endogenous genes are introduced. Molecular genetic approaches can expand the BVC repertoire of beneficial bacteria to target additional beneficial effects, or simply boost the production level of naturally occurring BVCs. The effects of direct BVC application in soil are reviewed and evaluated for potential large-scale field and agricultural applications. Our review of recent BVC data indicates that BVCs have great potential to serve as effective biostimulants and bioprotectants even under open-field conditions.

  1. SPRYSEC Effectors: A Versatile Protein-Binding Platform to Disrupt Plant Innate Immunity

    PubMed Central

    Diaz-Granados, Amalia; Petrescu, Andrei-José; Goverse, Aska; Smant, Geert

    2016-01-01

    Persistent infections by sedentary plant-parasitic nematodes are a major threat to important food crops all over the world. These roundworms manipulate host plant cell morphology and physiology to establish sophisticated feeding structures. Key modifications to plant cells during their transition into feeding structures are largely attributed to the activity of effectors secreted by the nematodes. The SPRYSEC effectors were initially identified in the potato cyst nematodes Globodera rostochiensis and G. pallida, and are characterized by a single SPRY domain, a non-catalytic domain present in modular proteins with different functions. The SPRY domain is wide-spread among eukaryotes and thought to be involved in mediating protein–protein interactions. Thus far, the SPRY domain is only reported as a functional domain in effectors of plant-parasitic nematodes, but not of other plant pathogens. SPRYSEC effectors have been implicated in both suppression and activation of plant immunity, but other possible roles in nematode virulence remain undefined. Here, we review the latest reports on the structure, function, and sequence diversity of SPRYSEC effectors, which provide support for a model featuring these effectors as a versatile protein-binding platform for the nematodes to target a wide range of host proteins during parasitism. PMID:27812363

  2. Multiple Classes of Immune-Related Proteases Associated with the Cell Death Response in Pepper Plants

    PubMed Central

    Bae, Chungyun; Kim, Su-min; Lee, Dong Ju; Choi, Doil

    2013-01-01

    Proteases regulate a large number of biological processes in plants, such as metabolism, physiology, growth, and defense. In this study, we carried out virus-induced gene silencing assays with pepper cDNA clones to elucidate the biological roles of protease superfamilies. A total of 153 representative protease genes from pepper cDNA were selected and cloned into a Tobacco rattle virus-ligation independent cloning vector in a loss-of-function study. Silencing of 61 proteases resulted in altered phenotypes, such as the inhibition of shoot growth, abnormal leaf shape, leaf color change, and lethality. Furthermore, the silencing experiments revealed that multiple proteases play a role in cell death and immune response against avirulent and virulent pathogens. Among these 153 proteases, 34 modulated the hypersensitive cell death response caused by infection with an avirulent pathogen, and 16 proteases affected disease symptom development caused by a virulent pathogen. Specifically, we provide experimental evidence for the roles of multiple protease genes in plant development and immune defense following pathogen infection. With these results, we created a broad sketch of each protease function. This information will provide basic information for further understanding the roles of the protease superfamily in plant growth, development, and defense. PMID:23696830

  3. A novel elicitor protein from Phytophthora parasitica induces plant basal immunity and systemic acquired resistance.

    PubMed

    Chang, Yi-Hsuan; Yan, Hao-Zhi; Liou, Ruey-Fen

    2015-02-01

    The interaction between Phytophthora pathogens and host plants involves the exchange of complex molecular signals from both sides. Recent studies of Phytophthora have led to the identification of various apoplastic elicitors known to trigger plant immunity. Here, we provide evidence that the protein encoded by OPEL of Phytophthora parasitica is a novel elicitor. Homologues of OPEL were identified only in oomycetes, but not in fungi and other organisms. Quantitative reverse transcription-polymerase chain reaction (RT-PCR) revealed that OPEL is expressed throughout the development of P. parasitica and is especially highly induced after plant infection. Infiltration of OPEL recombinant protein from Escherichia coli into leaves of Nicotiana tabacum (cv. Samsun NN) resulted in cell death, callose deposition, the production of reactive oxygen species and induced expression of pathogen-associated molecular pattern (PAMP)-triggered immunity markers and salicylic acid-responsive defence genes. Moreover, the infiltration conferred systemic resistance against a broad spectrum of pathogens, including Tobacco mosaic virus, the bacteria wilt pathogen Ralstonia solanacearum and P. parasitica. In addition to the signal peptide, OPEL contains three conserved domains: a thaumatin-like domain, a glycine-rich protein domain and a glycosyl hydrolase (GH) domain. Intriguingly, mutation of a putative laminarinase active site motif in the predicted GH domain abolished its elicitor activity, which suggests enzymatic activity of OPEL in triggering the defence response.

  4. Loss of a Conserved tRNA Anticodon Modification Perturbs Plant Immunity.

    PubMed

    Ramírez, Vicente; Gonzalez, Beatriz; López, Ana; Castelló, María José; Gil, María José; Etherington, Graham J; Zheng, Bo; Chen, Peng; Vera, Pablo

    2015-10-01

    tRNA is the most highly modified class of RNA species, and modifications are found in tRNAs from all organisms that have been examined. Despite their vastly different chemical structures and their presence in different tRNAs, occurring in different locations in tRNA, the biosynthetic pathways of the majority of tRNA modifications include a methylation step(s). Recent discoveries have revealed unprecedented complexity in the modification patterns of tRNA, their regulation and function, suggesting that each modified nucleoside in tRNA may have its own specific function. However, in plants, our knowledge on the role of individual tRNA modifications and how they are regulated is very limited. In a genetic screen designed to identify factors regulating disease resistance and activation of defenses in Arabidopsis, we identified SUPPRESSOR OF CSB3 9 (SCS9). Our results reveal SCS9 encodes a tRNA methyltransferase that mediates the 2´-O-ribose methylation of selected tRNA species in the anticodon loop. These SCS9-mediated tRNA modifications enhance during the course of infection with the bacterial pathogen Pseudomonas syringae DC3000, and lack of such tRNA modification, as observed in scs9 mutants, severely compromise plant immunity against the same pathogen without affecting the salicylic acid (SA) signaling pathway which regulates plant immune responses. Our results support a model that gives importance to the control of certain tRNA modifications for mounting an effective immune response in Arabidopsis, and therefore expands the repertoire of molecular components essential for an efficient disease resistance response.

  5. Loss of a Conserved tRNA Anticodon Modification Perturbs Plant Immunity

    PubMed Central

    López, Ana; Castelló, María José; Gil, María José; Zheng, Bo; Chen, Peng; Vera, Pablo

    2015-01-01

    tRNA is the most highly modified class of RNA species, and modifications are found in tRNAs from all organisms that have been examined. Despite their vastly different chemical structures and their presence in different tRNAs, occurring in different locations in tRNA, the biosynthetic pathways of the majority of tRNA modifications include a methylation step(s). Recent discoveries have revealed unprecedented complexity in the modification patterns of tRNA, their regulation and function, suggesting that each modified nucleoside in tRNA may have its own specific function. However, in plants, our knowledge on the role of individual tRNA modifications and how they are regulated is very limited. In a genetic screen designed to identify factors regulating disease resistance and activation of defenses in Arabidopsis, we identified SUPPRESSOR OF CSB3 9 (SCS9). Our results reveal SCS9 encodes a tRNA methyltransferase that mediates the 2´-O-ribose methylation of selected tRNA species in the anticodon loop. These SCS9-mediated tRNA modifications enhance during the course of infection with the bacterial pathogen Pseudomonas syringae DC3000, and lack of such tRNA modification, as observed in scs9 mutants, severely compromise plant immunity against the same pathogen without affecting the salicylic acid (SA) signaling pathway which regulates plant immune responses. Our results support a model that gives importance to the control of certain tRNA modifications for mounting an effective immune response in Arabidopsis, and therefore expands the repertoire of molecular components essential for an efficient disease resistance response. PMID:26492405

  6. Msp40 effector of root-knot nematode manipulates plant immunity to facilitate parasitism

    PubMed Central

    Niu, Junhai; Liu, Pei; Liu, Qian; Chen, Changlong; Guo, Quanxin; Yin, Junmei; Yang, Guangsui; Jian, Heng

    2016-01-01

    Root-knot nematodes (RKNs) are obligate biotrophic parasites that invade plant roots and engage in prolonged and intimate relationships with their hosts. Nematode secretions, some of which have immunosuppressing activity, play essential roles in successful parasitism; however, their mechanisms of action remain largely unknown. Here, we show that the RKN-specific gene MiMsp40, cloned from Meloidogyne incognita, is expressed exclusively in subventral oesophageal gland cells and is strongly upregulated during early parasitic stages. Arabidopsis plants overexpressing MiMsp40 were more susceptible to nematode infection than were wild type plants. Conversely, the host-derived MiMsp40 RNAi suppressed nematode parasitism and/or reproduction. Moreover, overexpression of MiMsp40 in plants suppressed the deposition of callose and the expression of marker genes for bacterial elicitor elf18-triggered immunity. Transient expression of MiMsp40 prevented Bax-triggered defence-related programmed cell death. Co-agroinfiltration assays indicated that MiMsp40 also suppressed macroscopic cell death triggered by MAPK cascades or by the ETI cognate elicitors R3a/Avr3a. Together, these results demonstrate that MiMsp40 is a novel Meloidogyne-specific effector that is injected into plant cells by early parasitic stages of the nematode and that plays a role in suppressing PTI and/or ETI signals to facilitate RKN parasitism. PMID:26797310

  7. Tomato receptor FLAGELLIN-SENSING 3 binds flgII-28 and activates the plant immune system.

    PubMed

    Hind, Sarah R; Strickler, Susan R; Boyle, Patrick C; Dunham, Diane M; Bao, Zhilong; O'Doherty, Inish M; Baccile, Joshua A; Hoki, Jason S; Viox, Elise G; Clarke, Christopher R; Vinatzer, Boris A; Schroeder, Frank C; Martin, Gregory B

    2016-01-01

    Plants and animals detect the presence of potential pathogens through the perception of conserved microbial patterns by cell surface receptors. Certain solanaceous plants, including tomato, potato and pepper, detect flgII-28, a region of bacterial flagellin that is distinct from that perceived by the well-characterized FLAGELLIN-SENSING 2 receptor. Here we identify and characterize the receptor responsible for this recognition in tomato, called FLAGELLIN-SENSING 3. This receptor binds flgII-28 and enhances immune responses leading to a reduction in bacterial colonization of leaf tissues. Further characterization of FLS3 and its signalling pathway could provide new insights into the plant immune system and transfer of the receptor to other crop plants offers the potential of enhancing resistance to bacterial pathogens that have evolved to evade FLS2-mediated immunity. PMID:27548463

  8. ChIP-seq reveals broad roles of SARD1 and CBP60g in regulating plant immunity

    PubMed Central

    Sun, Tongjun; Zhang, Yaxi; Li, Yan; Zhang, Qian; Ding, Yuli; Zhang, Yuelin

    2015-01-01

    Recognition of pathogens by host plants leads to rapid transcriptional reprogramming and activation of defence responses. The expression of many defence regulators is induced in this process, but the mechanisms of how they are controlled transcriptionally are largely unknown. Here we use chromatin immunoprecipitation sequencing to show that the transcription factors SARD1 and CBP60g bind to the promoter regions of a large number of genes encoding key regulators of plant immunity. Among them are positive regulators of systemic immunity and signalling components for effector-triggered immunity and PAMP-triggered immunity, which is consistent with the critical roles of SARD1 and CBP60g in these processes. In addition, SARD1 and CBP60g target a number of genes encoding negative regulators of plant immunity, suggesting that they are also involved in negative feedback regulation of defence responses. Based on these findings we propose that SARD1 and CBP60g function as master regulators of plant immune responses. PMID:27206545

  9. A bacterial cysteine protease effector protein interferes with photosynthesis to suppress plant innate immune responses.

    PubMed

    Rodríguez-Herva, José J; González-Melendi, Pablo; Cuartas-Lanza, Raquel; Antúnez-Lamas, María; Río-Alvarez, Isabel; Li, Ziduo; López-Torrejón, Gema; Díaz, Isabel; Del Pozo, Juan C; Chakravarthy, Suma; Collmer, Alan; Rodríguez-Palenzuela, Pablo; López-Solanilla, Emilia

    2012-05-01

    The bacterial pathogen Pseudomonas syringae pv tomato DC3000 suppresses plant innate immunity with effector proteins injected by a type III secretion system (T3SS). The cysteine protease effector HopN1, which reduces the ability of DC3000 to elicit programmed cell death in non-host tobacco, was found to also suppress the production of defence-associated reactive oxygen species (ROS) and callose when delivered by Pseudomonas fluorescens heterologously expressing a P. syringae T3SS. Purified His(6) -tagged HopN1 was used to identify tomato PsbQ, a member of the oxygen evolving complex of photosystem II (PSII), as an interacting protein. HopN1 localized to chloroplasts and both degraded PsbQ and inhibited PSII activity in chloroplast preparations, whereas a HopN1(D299A) non-catalytic mutant lost these abilities. Gene silencing of NtPsbQ in tobacco compromised ROS production and programmed cell death by DC3000. Our data reveal PsbQ as a contributor to plant immunity responses and a target for pathogen suppression.

  10. An E4 Ligase Facilitates Polyubiquitination of Plant Immune Receptor Resistance Proteins in Arabidopsis[W

    PubMed Central

    Huang, Yan; Minaker, Sean; Roth, Charlotte; Huang, Shuai; Hieter, Philip; Lipka, Volker; Wiermer, Marcel; Li, Xin

    2014-01-01

    Proteins with nucleotide binding and leucine-rich repeat domains (NLRs) serve as immune receptors in animals and plants that recognize pathogens and activate downstream defense responses. As high accumulation of NLRs can result in unwarranted autoimmune responses, their cellular concentrations must be tightly regulated. However, the molecular mechanisms of this process are poorly detailed. The F-box protein Constitutive expressor of PR genes 1 (CPR1) was previously identified as a component of a Skp1, Cullin1, F-box protein E3 complex that targets NLRs, including Suppressor of NPR1, Constitutive 1 (SNC1) and Resistance to Pseudomonas syringae 2 (RPS2), for ubiquitination and further protein degradation. From a forward genetic screen, we identified Mutant, snc1-enhancing 3 (MUSE3), an E4 ubiquitin ligase involved in polyubiquitination of its protein targets. Knocking out MUSE3 in Arabidopsis thaliana results in increased levels of NLRs, including SNC1 and RPS2, whereas overexpressing MUSE3 together with CPR1 enhances polyubiquitination and protein degradation of these immune receptors. This report on the functional role of an E4 ligase in plants provides insight into the scarcely understood NLR degradation pathway. PMID:24449689

  11. The release and induced immune responses of a plant-made and delivered antigen in the mouse gut.

    PubMed

    Pelosi, Assunta; Shepherd, Robert; Guzman, Giorgio De; Hamill, John D; Meeusen, Els; Sanson, Gordon; Walmsley, Amanda M

    2011-11-01

    This study investigated the site of release of a model vaccine antigen from plant cells and the corresponding induced immune response. Three plant tissues (leaf, fruit and hairy root) and two formulations (aqueous and lipid) were compared in two mouse trials. A developed technique that enabled detection of antigen release by plant cells determined that antigen release occurred at early sites of the gastrointestinal tract when delivered in leaf material and at later sites when delivered in hairy roots. Lipid formulations delayed antigen release from all plant materials tested. While encapsulation in the plant cell provided some protection of the antigen in the gastrointestinal tract and influenced antigen release, formulation medium was also an important consideration with regard to vaccine delivery and immunogenicity. Systemic immune responses induced from the orally delivered vaccine benefited from late release of antigen in the mouse gastrointestinal tract. The influences to the mucosal immune response induced by these vaccines were too complex to be determined by studies performed here with no clear trend regarding plant tissue site of release or formulation medium. Expression and delivery of the model antigen in plant material prepared in an aqueous formulation provided the optimal systemic and mucosal, antigen-specific immune responses.

  12. Spatial and temporal regulation of biosynthesis of the plant immune signal salicylic acid

    PubMed Central

    Zheng, Xiao-yu; Zhou, Mian; Yoo, Heejin; Pruneda-Paz, Jose L.; Spivey, Natalie Weaver; Kay, Steve A.; Dong, Xinnian

    2015-01-01

    The plant hormone salicylic acid (SA) is essential for local defense and systemic acquired resistance (SAR). When plants, such as Arabidopsis, are challenged by different pathogens, an increase in SA biosynthesis generally occurs through transcriptional induction of the key synthetic enzyme isochorismate synthase 1 (ICS1). However, the regulatory mechanism for this induction is poorly understood. Using a yeast one-hybrid screen, we identified two transcription factors (TFs), NTM1-LIKE 9 (NTL9) and CCA1 HIKING EXPEDITION (CHE), as activators of ICS1 during specific immune responses. NTL9 is essential for inducing ICS1 and two other SA synthesis-related genes, PHYTOALEXIN-DEFICIENT 4 (PAD4) and ENHANCED DISEASE SUSCEPTIBILITY 1 (EDS1), in guard cells that form stomata. Stomata can quickly close upon challenge to block pathogen entry. This stomatal immunity requires ICS1 and the SA signaling pathway. In the ntl9 mutant, this response is defective and can be rescued by exogenous application of SA, indicating that NTL9-mediated SA synthesis is essential for stomatal immunity. CHE, the second identified TF, is a central circadian clock oscillator and is required not only for the daily oscillation in SA levels but also for the pathogen-induced SA synthesis in systemic tissues during SAR. CHE may also regulate ICS1 through the known transcription activators CALMODULIN BINDING PROTEIN 60g (CBP60g) and SYSTEMIC ACQUIRED RESISTANCE DEFICIENT 1 (SARD1) because induction of these TF genes is compromised in the che-2 mutant. Our study shows that SA biosynthesis is regulated by multiple TFs in a spatial and temporal manner and therefore fills a gap in the signal transduction pathway between pathogen recognition and SA production. PMID:26139525

  13. Spatial and temporal regulation of biosynthesis of the plant immune signal salicylic acid.

    PubMed

    Zheng, Xiao-Yu; Zhou, Mian; Yoo, Heejin; Pruneda-Paz, Jose L; Spivey, Natalie Weaver; Kay, Steve A; Dong, Xinnian

    2015-07-28

    The plant hormone salicylic acid (SA) is essential for local defense and systemic acquired resistance (SAR). When plants, such as Arabidopsis, are challenged by different pathogens, an increase in SA biosynthesis generally occurs through transcriptional induction of the key synthetic enzyme isochorismate synthase 1 (ICS1). However, the regulatory mechanism for this induction is poorly understood. Using a yeast one-hybrid screen, we identified two transcription factors (TFs), NTM1-like 9 (NTL9) and CCA1 hiking expedition (CHE), as activators of ICS1 during specific immune responses. NTL9 is essential for inducing ICS1 and two other SA synthesis-related genes, phytoalexin-deficient 4 (PAD4) and enhanced disease susceptibility 1 (EDS1), in guard cells that form stomata. Stomata can quickly close upon challenge to block pathogen entry. This stomatal immunity requires ICS1 and the SA signaling pathway. In the ntl9 mutant, this response is defective and can be rescued by exogenous application of SA, indicating that NTL9-mediated SA synthesis is essential for stomatal immunity. CHE, the second identified TF, is a central circadian clock oscillator and is required not only for the daily oscillation in SA levels but also for the pathogen-induced SA synthesis in systemic tissues during SAR. CHE may also regulate ICS1 through the known transcription activators calmodulin binding protein 60g (CBP60g) and systemic acquired resistance deficient 1 (SARD1) because induction of these TF genes is compromised in the che-2 mutant. Our study shows that SA biosynthesis is regulated by multiple TFs in a spatial and temporal manner and therefore fills a gap in the signal transduction pathway between pathogen recognition and SA production.

  14. A plant-produced antigen elicits potent immune responses against West Nile virus in mice.

    PubMed

    He, Junyun; Peng, Li; Lai, Huafang; Hurtado, Jonathan; Stahnke, Jake; Chen, Qiang

    2014-01-01

    We described the rapid production of the domain III (DIII) of the envelope (E) protein in plants as a vaccine candidate for West Nile Virus (WNV). Using various combinations of vector modules of a deconstructed viral vector expression system, DIII was produced in three subcellular compartments in leaves of Nicotiana benthamiana by transient expression. DIII expressed at much higher levels when targeted to the endoplasmic reticulum (ER) than that targeted to the chloroplast or the cytosol, with accumulation level up to 73  μ g DIII per gram of leaf fresh weight within 4 days after infiltration. Plant ER-derived DIII was soluble and readily purified to > 95% homogeneity without the time-consuming process of denaturing and refolding. Further analysis revealed that plant-produced DIII was processed properly and demonstrated specific binding to an anti-DIII monoclonal antibody that recognizes a conformational epitope. Furthermore, subcutaneous immunization of mice with 5 and 25  μ g of purified DIII elicited a potent systemic response. This study provided the proof of principle for rapidly producing immunogenic vaccine candidates against WNV in plants with low cost and scalability. PMID:24804264

  15. Ca2+ -regulated lysosome fusion mediates angiotensin II-induced lipid raft clustering in mesenteric endothelial cells.

    PubMed

    Han, Wei-Qing; Chen, Wen-Dong; Zhang, Ke; Liu, Jian-Jun; Wu, Yong-Jie; Gao, Ping-Jin

    2016-04-01

    It has been reported that intracellular Ca2+ is involved in lysosome fusion and membrane repair in skeletal cells. Given that angiotensin II (Ang II) elicits an increase in intracellular Ca2+ and that lysosome fusion is a crucial mediator of lipid raft (LR) clustering, we hypothesized that Ang II induces lysosome fusion and activates LR formation in rat mesenteric endothelial cells (MECs). We found that Ang II acutely increased intracellular Ca2+ content, an effect that was inhibited by the extracellular Ca2+ chelator ethylene glycol tetraacetic acid (EGTA) and the inositol 1,4,5-trisphosphate (IP3)-induced Ca2+ release inhibitor 2-aminoethoxydiphenyl borate (2-APB). Further study showed that EGTA almost completely blocked Ang II-induced lysosome fusion, the translocation of acid sphingomyelinase (ASMase) to LR clusters, ASMase activation and NADPH (nicotinamide adenine dinucleotide phosphate) oxidase activation. In contrast, 2-APB had a slight inhibitory effect. Functionally, both the lysosome inhibitor bafilomycin A1 and the ASMase inhibitor amitriptyline reversed Ang II-induced impairment of vasodilation. We conclude that Ca2+ -regulated lysosome fusion mediates the Ang II-induced regulation of the LR-redox signaling pathway and mesenteric endothelial dysfunction.

  16. Elongator subunit 3 positively regulates plant immunity through its histone acetyltransferase and radical S-adenosylmethionine domains

    PubMed Central

    2013-01-01

    Background Pathogen infection triggers a large-scale transcriptional reprogramming in plants, and the speed of this reprogramming affects the outcome of the infection. Our understanding of this process has significantly benefited from mutants that display either delayed or accelerated defense gene induction. In our previous work we demonstrated that the Arabidopsis Elongator complex subunit 2 (AtELP2) plays an important role in both basal immunity and effector-triggered immunity (ETI), and more recently showed that AtELP2 is involved in dynamic changes in histone acetylation and DNA methylation at several defense genes. However, the function of other Elongator subunits in plant immunity has not been characterized. Results In the same genetic screen used to identify Atelp2, we found another Elongator mutant, Atelp3-10, which mimics Atelp2 in that it exhibits a delay in defense gene induction following salicylic acid treatment or pathogen infection. Similarly to AtELP2, AtELP3 is required for basal immunity and ETI, but not for systemic acquired resistance (SAR). Furthermore, we demonstrate that both the histone acetyltransferase and radical S-adenosylmethionine domains of AtELP3 are essential for its function in plant immunity. Conclusion Our results indicate that the entire Elongator complex is involved in basal immunity and ETI, but not in SAR, and support that Elongator may play a role in facilitating the transcriptional induction of defense genes through alterations to their chromatin. PMID:23856002

  17. Double-stranded RNAs induce a pattern-triggered immune signaling pathway in plants.

    PubMed

    Niehl, Annette; Wyrsch, Ines; Boller, Thomas; Heinlein, Manfred

    2016-08-01

    Pattern-triggered immunity (PTI) is a plant defense response that relies on the perception of conserved microbe- or pathogen-associated molecular patterns (MAMPs or PAMPs, respectively). Recently, it has been recognized that PTI restricts virus infection in plants; however, the nature of the viral or infection-induced PTI elicitors and the underlying signaling pathways are still unknown. As double-stranded RNAs (dsRNAs) are conserved molecular patterns associated with virus replication, we applied dsRNAs or synthetic dsRNA analogs to Arabidopsis thaliana and investigated PTI responses. We show that in vitro-generated dsRNAs, dsRNAs purified from virus-infected plants and the dsRNA analog polyinosinic-polycytidylic acid (poly(I:C)) induce typical PTI responses dependent on the co-receptor SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE 1 (SERK1), but independent of dicer-like (DCL) proteins in Arabidopsis. Moreover, dsRNA treatment of Arabidopsis induces SERK1-dependent antiviral resistance. Screening of Arabidopsis wild accessions demonstrates natural variability in dsRNA sensitivity. Our findings suggest that dsRNAs represent genuine PAMPs in plants, which induce a signaling cascade involving SERK1 and a specific dsRNA receptor. The dependence of dsRNA-mediated PTI on SERK1, but not on DCLs, implies that dsRNA-mediated PTI involves membrane-associated processes and operates independently of RNA silencing. dsRNA sensitivity may represent a useful trait to increase antiviral resistance in cultivated plants.

  18. Double-stranded RNAs induce a pattern-triggered immune signaling pathway in plants.

    PubMed

    Niehl, Annette; Wyrsch, Ines; Boller, Thomas; Heinlein, Manfred

    2016-08-01

    Pattern-triggered immunity (PTI) is a plant defense response that relies on the perception of conserved microbe- or pathogen-associated molecular patterns (MAMPs or PAMPs, respectively). Recently, it has been recognized that PTI restricts virus infection in plants; however, the nature of the viral or infection-induced PTI elicitors and the underlying signaling pathways are still unknown. As double-stranded RNAs (dsRNAs) are conserved molecular patterns associated with virus replication, we applied dsRNAs or synthetic dsRNA analogs to Arabidopsis thaliana and investigated PTI responses. We show that in vitro-generated dsRNAs, dsRNAs purified from virus-infected plants and the dsRNA analog polyinosinic-polycytidylic acid (poly(I:C)) induce typical PTI responses dependent on the co-receptor SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE 1 (SERK1), but independent of dicer-like (DCL) proteins in Arabidopsis. Moreover, dsRNA treatment of Arabidopsis induces SERK1-dependent antiviral resistance. Screening of Arabidopsis wild accessions demonstrates natural variability in dsRNA sensitivity. Our findings suggest that dsRNAs represent genuine PAMPs in plants, which induce a signaling cascade involving SERK1 and a specific dsRNA receptor. The dependence of dsRNA-mediated PTI on SERK1, but not on DCLs, implies that dsRNA-mediated PTI involves membrane-associated processes and operates independently of RNA silencing. dsRNA sensitivity may represent a useful trait to increase antiviral resistance in cultivated plants. PMID:27030513

  19. Tight regulation of plant immune responses by combining promoter and suicide exon elements

    PubMed Central

    Gonzalez, Tania L.; Liang, Yan; Nguyen, Bao N.; Staskawicz, Brian J.; Loqué, Dominique; Hammond, Ming C.

    2015-01-01

    Effector-triggered immunity (ETI) is activated when plant disease resistance (R) proteins recognize the presence of pathogen effector proteins delivered into host cells. The ETI response generally encompasses a defensive ‘hypersensitive response’ (HR) that involves programmed cell death at the site of pathogen recognition. While many R protein and effector protein pairs are known to trigger HR, other components of the ETI signaling pathway remain elusive. Effector genes regulated by inducible promoters cause background HR due to leaky protein expression, preventing the generation of relevant transgenic plant lines. By employing the HyP5SM suicide exon, we have developed a strategy to tightly regulate effector proteins such that HR is chemically inducible and non-leaky. This alternative splicing-based gene regulation system was shown to successfully control Bs2/AvrBs2-dependent and RPP1/ATR1Δ51-dependent HR in Nicotiana benthamiana and Nicotiana tabacum, respectively. It was also used to generate viable and healthy transgenic Arabidopsis thaliana plants that inducibly initiate HR. Beyond enabling studies on the ETI pathway, our regulatory strategy is generally applicable to reduce or eliminate undesired background expression of transgenes. PMID:26138488

  20. Tight regulation of plant immune responses by combining promoter and suicide exon elements

    SciTech Connect

    Gonzalez, Tania L.; Liang, Yan; Nguyen, Bao N.; Staskawicz, Brian J.; Loqué, Dominique; Hammond, Ming C.

    2015-07-02

    Effector-triggered immunity (ETI) is activated when plant disease resistance (R) proteins recognize the presence of pathogen effector proteins delivered into host cells. The ETI response generally encompasses a defensive ‘hypersensitive response’ (HR) that involves programmed cell death at the site of pathogen recognition. While many R protein and effector protein pairs are known to trigger HR, other components of the ETI signaling pathway remain elusive. Effector genes regulated by inducible promoters cause background HR due to leaky protein expression, preventing the generation of relevant transgenic plant lines. By employing the HyP5SM suicide exon, we have developed a strategy to tightly regulate effector proteins such that HR is chemically inducible and non-leaky. This alternative splicing-based gene regulation system was shown to successfully control Bs2/AvrBs2-dependent and RPP1/ATR1Δ51-dependent HR in Nicotiana benthamiana and Nicotiana tabacum, respectively. It was also used to generate viable and healthy transgenic Arabidopsis thaliana plants that inducibly initiate HR. In conclusion, beyond enabling studies on the ETI pathway, our regulatory strategy is generally applicable to reduce or eliminate undesired background expression of transgenes.

  1. Tight regulation of plant immune responses by combining promoter and suicide exon elements

    DOE PAGES

    Gonzalez, Tania L.; Liang, Yan; Nguyen, Bao N.; Staskawicz, Brian J.; Loqué, Dominique; Hammond, Ming C.

    2015-07-02

    Effector-triggered immunity (ETI) is activated when plant disease resistance (R) proteins recognize the presence of pathogen effector proteins delivered into host cells. The ETI response generally encompasses a defensive ‘hypersensitive response’ (HR) that involves programmed cell death at the site of pathogen recognition. While many R protein and effector protein pairs are known to trigger HR, other components of the ETI signaling pathway remain elusive. Effector genes regulated by inducible promoters cause background HR due to leaky protein expression, preventing the generation of relevant transgenic plant lines. By employing the HyP5SM suicide exon, we have developed a strategy to tightlymore » regulate effector proteins such that HR is chemically inducible and non-leaky. This alternative splicing-based gene regulation system was shown to successfully control Bs2/AvrBs2-dependent and RPP1/ATR1Δ51-dependent HR in Nicotiana benthamiana and Nicotiana tabacum, respectively. It was also used to generate viable and healthy transgenic Arabidopsis thaliana plants that inducibly initiate HR. In conclusion, beyond enabling studies on the ETI pathway, our regulatory strategy is generally applicable to reduce or eliminate undesired background expression of transgenes.« less

  2. Burkholderia cenocepacia Lipopolysaccharide Modification and Flagellin Glycosylation Affect Virulence but Not Innate Immune Recognition in Plants

    PubMed Central

    Khodai-Kalaki, Maryam; Andrade, Angel; Fathy Mohamed, Yasmine

    2015-01-01

    ABSTRACT Burkholderia cenocepacia causes opportunistic infections in plants, insects, animals, and humans, suggesting that “virulence” depends on the host and its innate susceptibility to infection. We hypothesized that modifications in key bacterial molecules recognized by the innate immune system modulate host responses to B. cenocepacia. Indeed, modification of lipopolysaccharide (LPS) with 4-amino-4-deoxy-l-arabinose and flagellin glycosylation attenuates B. cenocepacia infection in Arabidopsis thaliana and Galleria mellonella insect larvae. However, B. cenocepacia LPS and flagellin triggered rapid bursts of nitric oxide and reactive oxygen species in A. thaliana leading to activation of the PR-1 defense gene. These responses were drastically reduced in plants with fls2 (flagellin FLS2 host receptor kinase), Atnoa1 (nitric oxide-associated protein 1), and dnd1-1 (reduced production of nitric oxide) null mutations. Together, our results indicate that LPS modification and flagellin glycosylation do not affect recognition by plant receptors but are required for bacteria to establish overt infection. PMID:26045541

  3. Nitric oxide and S-nitrosoglutathione function additively during plant immunity.

    PubMed

    Yun, Byung-Wook; Skelly, Michael J; Yin, Minghui; Yu, Manda; Mun, Bong-Gyu; Lee, Sang-Uk; Hussain, Adil; Spoel, Steven H; Loake, Gary J

    2016-07-01

    Nitric oxide (NO) is emerging as a key regulator of diverse plant cellular processes. A major route for the transfer of NO bioactivity is S-nitrosylation, the addition of an NO moiety to a protein cysteine thiol forming an S-nitrosothiol (SNO). Total cellular levels of protein S-nitrosylation are controlled predominantly by S-nitrosoglutathione reductase 1 (GSNOR1) which turns over the natural NO donor, S-nitrosoglutathione (GSNO). In the absence of GSNOR1 function, GSNO accumulates, leading to dysregulation of total cellular S-nitrosylation. Here we show that endogenous NO accumulation in Arabidopsis, resulting from loss-of-function mutations in NO Overexpression 1 (NOX1), led to disabled Resistance (R) gene-mediated protection, basal resistance and defence against nonadapted pathogens. In nox1 plants both salicylic acid (SA) synthesis and signalling were suppressed, reducing SA-dependent defence gene expression. Significantly, expression of a GSNOR1 transgene complemented the SNO-dependent phenotypes of paraquat resistant 2-1 (par2-1) plants but not the NO-related characters of the nox1-1 line. Furthermore, atgsnor1-3 nox1-1 double mutants supported greater bacterial titres than either of the corresponding single mutants. Our findings imply that GSNO and NO, two pivotal redox signalling molecules, exhibit additive functions and, by extension, may have distinct or overlapping molecular targets during both immunity and development.

  4. Atypical E2F transcriptional repressor DEL1 acts at the intersection of plant growth and immunity by controlling the hormone salicylic acid.

    PubMed

    Chandran, Divya; Rickert, Joshua; Huang, Yingxiang; Steinwand, Michael A; Marr, Sharon K; Wildermuth, Mary C

    2014-04-01

    In plants, the activation of immunity is often inversely correlated with growth. Mechanisms that control plant growth in the context of pathogen challenge and immunity are unclear. Investigating Arabidopsis infection with the powdery mildew fungus, we find that the Arabidopsis atypical E2F DEL1, a transcriptional repressor known to promote cell proliferation, represses accumulation of the hormone salicylic acid (SA), an established regulator of plant immunity. DEL1-deficient plants are more resistant to pathogens and slightly smaller than wild-type. The resistance and size phenotypes of DEL1-deficient plants are due to the induction of SA and activation of immunity in the absence of pathogen challenge. Moreover, Enhanced Disease Susceptibility 5 (EDS5), a SA transporter required for elevated SA and immunity, is a direct repressed target of DEL1. Together, these findings indicate that DEL1 control of SA levels contributes to regulating the balance between growth and immunity in developing leaves.

  5. The GHKL ATPase MORC1 Modulates Species-Specific Plant Immunity in Solanaceae.

    PubMed

    Manosalva, Patricia; Manohar, Murli; Kogel, Karl-Heinz; Kang, Hong-Gu; Klessig, Daniel F

    2015-08-01

    The microrchidia (MORC) proteins, a subset of the GHKL ATPase superfamily, were recently described as components involved in transcriptional gene silencing and plant immunity in Arabidopsis. To assess the role of MORC1 during resistance to Phytophthora infestans in solanaceous species, we altered the expression of the corresponding MORC1 homologs in potato, tomato, and Nicotiana benthamiana. Basal resistance to P. infestans was compromised in StMORC1-silenced potato and enhanced in overexpressing lines, indicating that StMORC1 positively affects immunity. By contrast, silencing SlMORC1 expression in tomato or NbMORC1 expression in N. benthamiana enhanced basal resistance to this oomycete pathogen. In addition, silencing SlMORC1 further enhanced resistance conferred by two resistance genes in tomato. Transient expression of StMORC1 in N. benthamiana accelerated cell death induced by infestin1 (INF1), whereas SlMORC1 or NbMORC1 suppressed it. Domain-swapping and mutational analyses indicated that the C-terminal region dictates the species-specific effects of the solanaceous MORC1 proteins on INF1-induced cell death. This C-terminal region also was required for homodimerization and phosphorylation of recombinant StMORC1 and SlMORC1, and its transient expression induced spontaneous cell death in N. benthamiana. Thus, this C-terminal region likely plays important roles in both determining and modulating the biological activity of MORC1 proteins.

  6. The GHKL ATPase MORC1 Modulates Species-Specific Plant Immunity in Solanaceae.

    PubMed

    Manosalva, Patricia; Manohar, Murli; Kogel, Karl-Heinz; Kang, Hong-Gu; Klessig, Daniel F

    2015-08-01

    The microrchidia (MORC) proteins, a subset of the GHKL ATPase superfamily, were recently described as components involved in transcriptional gene silencing and plant immunity in Arabidopsis. To assess the role of MORC1 during resistance to Phytophthora infestans in solanaceous species, we altered the expression of the corresponding MORC1 homologs in potato, tomato, and Nicotiana benthamiana. Basal resistance to P. infestans was compromised in StMORC1-silenced potato and enhanced in overexpressing lines, indicating that StMORC1 positively affects immunity. By contrast, silencing SlMORC1 expression in tomato or NbMORC1 expression in N. benthamiana enhanced basal resistance to this oomycete pathogen. In addition, silencing SlMORC1 further enhanced resistance conferred by two resistance genes in tomato. Transient expression of StMORC1 in N. benthamiana accelerated cell death induced by infestin1 (INF1), whereas SlMORC1 or NbMORC1 suppressed it. Domain-swapping and mutational analyses indicated that the C-terminal region dictates the species-specific effects of the solanaceous MORC1 proteins on INF1-induced cell death. This C-terminal region also was required for homodimerization and phosphorylation of recombinant StMORC1 and SlMORC1, and its transient expression induced spontaneous cell death in N. benthamiana. Thus, this C-terminal region likely plays important roles in both determining and modulating the biological activity of MORC1 proteins. PMID:25822715

  7. Transportin-SR Is Required for Proper Splicing of Resistance Genes and Plant Immunity

    PubMed Central

    Xu, Shaohua; Zhang, Zhibin; Jing, Beibei; Gannon, Patrick; Ding, Jinmei; Xu, Fang; Li, Xin; Zhang, Yuelin

    2011-01-01

    Transportin-SR (TRN-SR) is a member of the importin-β super-family that functions as the nuclear import receptor for serine-arginine rich (SR) proteins, which play diverse roles in RNA metabolism. Here we report the identification and cloning of mos14 (modifier of snc1-1, 14), a mutation that suppresses the immune responses conditioned by the auto-activated Resistance (R) protein snc1 (suppressor of npr1-1, constitutive 1). MOS14 encodes a nuclear protein with high similarity to previously characterized TRN-SR proteins in animals. Yeast two-hybrid assays showed that MOS14 interacts with AtRAN1 via its N-terminus and SR proteins via its C-terminus. In mos14-1, localization of several SR proteins to the nucleus was impaired, confirming that MOS14 functions as a TRN-SR. The mos14-1 mutation results in altered splicing patterns of SNC1 and another R gene RPS4 and compromised resistance mediated by snc1 and RPS4, suggesting that nuclear import of SR proteins by MOS14 is required for proper splicing of these two R genes and is important for their functions in plant immunity. PMID:21738492

  8. Beyond Glycolysis: GAPDHs Are Multi-functional Enzymes Involved in Regulation of ROS, Autophagy, and Plant Immune Responses

    PubMed Central

    Henry, Elizabeth; Fung, Nicholas; Liu, Jun; Drakakaki, Georgia; Coaker, Gitta

    2015-01-01

    Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is an important enzyme in energy metabolism with diverse cellular regulatory roles in vertebrates, but few reports have investigated the importance of plant GAPDH isoforms outside of their role in glycolysis. While animals possess one GAPDH isoform, plants possess multiple isoforms. In this study, cell biological and genetic approaches were used to investigate the role of GAPDHs during plant immune responses. Individual Arabidopsis GAPDH knockouts (KO lines) exhibited enhanced disease resistance phenotypes upon inoculation with the bacterial plant pathogen Pseudomonas syringae pv. tomato. KO lines exhibited accelerated programmed cell death and increased electrolyte leakage in response to effector triggered immunity. Furthermore, KO lines displayed increased basal ROS accumulation as visualized using the fluorescent probe H2DCFDA. The gapa1-2 and gapc1 KOs exhibited constitutive autophagy phenotypes in the absence of nutrient starvation. Due to the high sequence conservation between vertebrate and plant cytosolic GAPDH, our experiments focused on cytosolic GAPC1 cellular dynamics using a complemented GAPC1-GFP line. Confocal imaging coupled with an endocytic membrane marker (FM4-64) and endosomal trafficking inhibitors (BFA, Wortmannin) demonstrated cytosolic GAPC1 is localized to the plasma membrane and the endomembrane system, in addition to the cytosol and nucleus. After perception of bacterial flagellin, GAPC1 dynamically responded with a significant increase in size of fluorescent puncta and enhanced nuclear accumulation. Taken together, these results indicate that plant GAPDHs can affect multiple aspects of plant immunity in diverse sub-cellular compartments. PMID:25918875

  9. ER bodies in plants of the Brassicales order: biogenesis and association with innate immunity

    PubMed Central

    Nakano, Ryohei T.; Yamada, Kenji; Bednarek, Paweł; Nishimura, Mikio; Hara-Nishimura, Ikuko

    2014-01-01

    The endoplasmic reticulum (ER) forms highly organized network structures composed of tubules and cisternae. Many plant species develop additional ER-derived structures, most of which are specific for certain groups of species. In particular, a rod-shaped structure designated as the ER body is produced by plants of the Brassicales order, which includes Arabidopsis thaliana. Genetic analyses and characterization of A. thaliana mutants possessing a disorganized ER morphology or lacking ER bodies have provided insights into the highly organized mechanisms responsible for the formation of these unique ER structures. The accumulation of proteins specific for the ER body within the ER plays an important role in the formation of ER bodies. However, a mutant that exhibits morphological defects of both the ER and ER bodies has not been identified. This suggests that plants in the Brassicales order have evolved novel mechanisms for the development of this unique organelle, which are distinct from those used to maintain generic ER structures. In A. thaliana, ER bodies are ubiquitous in seedlings and roots, but rare in rosette leaves. Wounding of rosette leaves induces de novo formation of ER bodies, suggesting that these structures are associated with resistance against pathogens and/or herbivores. ER bodies accumulate a large amount of β-glucosidases, which can produce substances that potentially protect against invading pests. Biochemical studies have determined that the enzymatic activities of these β-glucosidases are enhanced during cell collapse. These results suggest that ER bodies are involved in plant immunity, although there is no direct evidence of this. In this review, we provide recent perspectives of ER and ER body formation in A. thaliana, and discuss clues for the functions of ER bodies. We highlight defense strategies against biotic stress that are unique for the Brassicales order, and discuss how ER structures could contribute to these strategies. PMID

  10. Regulation of plant immunity through ubiquitin-mediated modulation of Ca(2+) -calmodulin-AtSR1/CAMTA3 signaling.

    PubMed

    Zhang, Lei; Du, Liqun; Shen, Chenjia; Yang, Yanjun; Poovaiah, B W

    2014-04-01

    Transient changes in intracellular Ca(2+) concentration are essential signals for activation of plant immunity. It has also been reported that Ca(2+) signals suppress salicylic acid-mediated plant defense through AtSR1/CAMTA3, a member of the Ca(2+) /calmodulin-regulated transcription factor family that is conserved in multicellular eukaryotes. How plants overcome this negative regulation to mount an effective defense response during a stage of intracellular Ca(2+) surge is unclear. Here we report the identification and functional characterization of an important component of ubiquitin ligase, and the associated AtSR1 turnover. The AtSR1 interaction protein 1 (SR1IP1) was identified by CytoTrap two-hybrid screening. The loss-of-function mutant of SR1IP1 is more susceptible to bacterial pathogens, and over-expression of SR1IP1 confers enhanced resistance, indicating that SR1IP1 acts as a positive regulator of plant defense. SR1IP1 and AtSR1 act in the same signaling pathway to regulate plant immunity. SR1IP1 contains the structural features of a substrate adaptor in cullin 3-based E3 ubiquitin ligase, and was shown to serve as a substrate adaptor that recruits AtSR1 for ubiquitination and degradation when plants are challenged with pathogens. Hence, SR1IP1 positively regulates plant immunity by removing the defense suppressor AtSR1. These findings provide a mechanistic insight into how Ca(2+) -mediated actions are coordinated to achieve effective plant immunity.

  11. Studying the Mechanism of Plasmopara viticola RxLR Effectors on Suppressing Plant Immunity

    PubMed Central

    Xiang, Jiang; Li, Xinlong; Wu, Jiao; Yin, Ling; Zhang, Yali; Lu, Jiang

    2016-01-01

    The RxLR effector family, produced by oomycete pathogens, may manipulate host physiological and biochemical events inside host cells. A group of putative RxLR effectors from Plasmopara viticola have been recently identified by RNA-Seq analysis in our lab. However, their roles in pathogenesis are poorly understood. In this study, we attempted to characterize 23 PvRxLR effector candidates identified from a P. viticola isolate “ZJ-1-1.” During host infection stages, expression patterns of the effector genes were varied and could be categorized into four different groups. By using transient expression assays in Nicotiana benthamiana, we found that 17 of these effector candidates fully suppressed programmed cell death elicited by a range of cell death-inducing proteins, including BAX, INF1, PsCRN63, PsojNIP, PvRxLR16 and R3a/Avr3a. We also discovered that all these PvRxLRs could target the plant cell nucleus, except for PvRxLR55 that localized to the membrane. Furthermore, we identified a single effector, PvRxLR28, that showed the highest expression level at 6 hpi. Functional analysis revealed that PvRxLR28 could significantly enhance susceptibilities of grapevine and tobacco to pathogens. These results suggest that most P. viticola effectors tested in this study may act as broad suppressors of cell death to manipulate immunity in plant. PMID:27242731

  12. [Group immunity against tularemia in employees of the Zelenina Processing Plant in Brno].

    PubMed

    Cerný, Z

    1991-11-01

    The authors examined, using the tularin test of Soviet make a total of 1380 employees of 14 work places of the national enterprise Zelenina in Brno. These work places are concerned with the purchasing, storage, distribution and sale of fruit and vegetables, grown among others also in South Moravian areas contaminated with tularaemia. They detected a total of 71 positive reactions concentrated mainly among long-term workers of the main storage places and transport departments of eight plants, i.e. Boskovice, Prostĕjov, Brno-town, Breclav, Trebíc, Brno-rural area, Slavkov and Znojmo, where the total tularaemia immunity rate varied between 4.88 and 12.30%. The distribution of positive cases signalizes with a high probability the occupational character of thus retrospectively detected cases, similarly as in the sugar plants and in the enterprise Fruta where products from the above area are processed. The source of infection are most probably rodents and the medium of transmission is probably fruit and in particular vegetables from the South Moravian area with tularaemia. The author recommends to introduce provisions to protect workers with risk occupations and possibly also consumers buying these products in retail shops. PMID:1838710

  13. Dietary medicinal plant extracts improve growth, immune activity and survival of tilapia Oreochromis mossambicus.

    PubMed

    Immanuel, G; Uma, R P; Iyapparaj, P; Citarasu, T; Peter, S M Punitha; Babu, M Michael; Palavesam, A

    2009-05-01

    The effects of supplementing diets with acetone extract (1% w/w) from four medicinal plants (Bermuda grass Cynodon dactylon, H(1), beal Aegle marmelos, H(2), winter cherry Withania somnifera, H(3) and ginger Zingiber officinale, H(4)) on growth, the non-specific immune response and ability to resist pathogen infection in tilapia Oreochromis mossambicus were assessed. In addition, the antimicrobial properties of the extract were assessed against Vibrio alginolyticus, Vibrioparahaemolyticus, Vibrio mimicus, Vibrio campbelli, Vibrio vulnificus, Vibrio harveyi and Photobacterium damselae. Oreochromis mossambicus were fed 5% of their body mass per day for 45 days, and those fed the experimental diets showed a greater increase in mass (111-139%) over the 45 days compared to those that received the control diet (98%). The specific growth rate of O. mossambicus fed the four diets was also significantly greater (1.66-1.93%) than control (1.52%) diet-fed fish. The blood plasma chemistry analysis revealed that protein, albumin, globulin, cholesterol, glucose and triglyceride levels of experimental fish were significantly higher than that of control fish. Packed cell volume of the blood samples of experimental diet-fed fish was also significantly higher (34.16-37.95%) than control fish (33.0%). Leucocrit value, phagocytic index and lysozyme activity were enhanced in fish fed the plant extract-supplemented diets. The acetone extract of the plants inhibited growth of Vibrio spp. and P. damselae with extracts from W. somnifera showing maximum growth inhibition. A challenge test with V. vulnificus showed 100% mortality in O. mossambicus fed the control diet by day 15, whereas the fish fed the experimental diets registered only 63-80% mortality at the end of challenge experiment (30 days). The cumulative mortality index for the control group was 12,000, which was equated to 1.0% mortality, and accordingly, the lowest mortality of 0.35% was registered in H(4)-diet-fed group. PMID

  14. Inter-organ defense networking: Leaf whitefly sucking elicits plant immunity to crown gall disease caused by Agrobacterium tumefaciens.

    PubMed

    Park, Yong-Soon; Ryu, Choong-Min

    2015-01-01

    Plants have elaborate defensive machinery to protect against numerous pathogens and insects. Plant hormones function as modulators of defensive mechanisms to maintain plant resistance to natural enemies. Our recent study suggests that salicylic acid (SA) is the primary phytohormone regulating plant responses to Agrobacterium tumefaciens infection. Tobacco (Nicotiana benthamiana Domin.) immune responses against Agrobacterium-mediated crown gall disease were activated by exposure to the sucking insect whitefly, which stimulated SA biosynthesis in aerial tissues; in turn, SA synthesized in aboveground tissues systemically modulated SA secretion in root tissues. Further investigation revealed that endogenous SA biosynthesis negatively modulated Agrobacterium-mediated plant genetic transformation. Our study provides novel evidence that activation of the SA-signaling pathway mediated by a sucking insect infestation has a pivotal role in subsequently attenuating Agrobacterium infection. These results demonstrate new insights into interspecies cross-talking among insects, plants, and soil bacteria. PMID:26357873

  15. Inter-organ defense networking: Leaf whitefly sucking elicits plant immunity to crown gall disease caused by Agrobacterium tumefaciens

    PubMed Central

    Park, Yong-Soon; Ryu, Choong-Min

    2015-01-01

    Plants have elaborate defensive machinery to protect against numerous pathogens and insects. Plant hormones function as modulators of defensive mechanisms to maintain plant resistance to natural enemies. Our recent study suggests that salicylic acid (SA) is the primary phytohormone regulating plant responses to Agrobacterium tumefaciens infection. Tobacco (Nicotiana benthamiana Domin.) immune responses against Agrobacterium-mediated crown gall disease were activated by exposure to the sucking insect whitefly, which stimulated SA biosynthesis in aerial tissues; in turn, SA synthesized in aboveground tissues systemically modulated SA secretion in root tissues. Further investigation revealed that endogenous SA biosynthesis negatively modulated Agrobacterium-mediated plant genetic transformation. Our study provides novel evidence that activation of the SA-signaling pathway mediated by a sucking insect infestation has a pivotal role in subsequently attenuating Agrobacterium infection. These results demonstrate new insights into interspecies cross-talking among insects, plants, and soil bacteria. PMID:26357873

  16. The hnRNP-Q Protein LIF2 Participates in the Plant Immune Response

    PubMed Central

    Le Roux, Clémentine; Del Prete, Stefania; Boutet-Mercey, Stéphanie; Perreau, François; Balagué, Claudine; Roby, Dominique; Fagard, Mathilde; Gaudin, Valérie

    2014-01-01

    Eukaryotes have evolved complex defense pathways to combat invading pathogens. Here, we investigated the role of the Arabidopsis thaliana heterogeneous nuclear ribonucleoprotein (hnRNP-Q) LIF2 in the plant innate immune response. We show that LIF2 loss-of-function in A. thaliana leads to changes in the basal expression of the salicylic acid (SA)- and jasmonic acid (JA)- dependent defense marker genes PR1 and PDF1.2, respectively. Whereas the expression of genes involved in SA and JA biosynthesis and signaling was also affected in the lif2-1 mutant, no change in SA and JA hormonal contents was detected. In addition, the composition of glucosinolates, a class of defense-related secondary metabolites, was altered in the lif2-1 mutant in the absence of pathogen challenge. The lif2-1 mutant exhibited reduced susceptibility to the hemi-biotrophic pathogen Pseudomonas syringae and the necrotrophic ascomycete Botrytis cinerea. Furthermore, the lif2-1 sid2-2 double mutant was less susceptible than the wild type to P. syringae infection, suggesting that the lif2 response to pathogens was independent of SA accumulation. Together, our data suggest that lif2-1 exhibits a basal primed defense state, resulting from complex deregulation of gene expression, which leads to increased resistance to pathogens with various infection strategies. Therefore, LIF2 may function as a suppressor of cell-autonomous immunity. Similar to its human homolog, NSAP1/SYNCRIP, a trans-acting factor involved in both cellular processes and the viral life cycle, LIF2 may regulate the conflicting aspects of development and defense programs, suggesting that a conserved evolutionary trade-off between growth and defense pathways exists in eukaryotes. PMID:24914891

  17. Integration of decoy domains derived from protein targets of pathogen effectors into plant immune receptors is widespread.

    PubMed

    Kroj, Thomas; Chanclud, Emilie; Michel-Romiti, Corinne; Grand, Xavier; Morel, Jean-Benoit

    2016-04-01

    Plant immune receptors of the class of nucleotide-binding and leucine-rich repeat domain (NLR) proteins can contain additional domains besides canonical NB-ARC (nucleotide-binding adaptor shared by APAF-1, R proteins, and CED-4 (NB-ARC)) and leucine-rich repeat (LRR) domains. Recent research suggests that these additional domains act as integrated decoys recognizing effectors from pathogens. Proteins homologous to integrated decoys are suspected to be effector targets and involved in disease or resistance. Here, we scrutinized 31 entire plant genomes to identify putative integrated decoy domains in NLR proteins using the Interpro search. The involvement of the Zinc Finger-BED type (ZBED) protein containing a putative decoy domain, called BED, in rice (Oryza sativa) resistance was investigated by evaluating susceptibility to the blast fungus Magnaporthe oryzae in rice over-expression and knock-out mutants. This analysis showed that all plants tested had integrated various atypical protein domains into their NLR proteins (on average 3.5% of all NLR proteins). We also demonstrated that modifying the expression of the ZBED gene modified disease susceptibility. This study suggests that integration of decoy domains in NLR immune receptors is widespread and frequent in plants. The integrated decoy model is therefore a powerful concept to identify new proteins involved in disease resistance. Further in-depth examination of additional domains in NLR proteins promises to unravel many new proteins of the plant immune system. PMID:26848538

  18. A Small Cysteine-Rich Protein from the Asian Soybean Rust Fungus, Phakopsora pachyrhizi, Suppresses Plant Immunity

    PubMed Central

    Qi, Mingsheng; Link, Tobias I.; Müller, Manuel; Hirschburger, Daniela; Pudake, Ramesh N.; Pedley, Kerry F.; Braun, Edward; Voegele, Ralf T.; Baum, Thomas J.

    2016-01-01

    The Asian soybean rust fungus, Phakopsora pachyrhizi, is an obligate biotrophic pathogen causing severe soybean disease epidemics. Molecular mechanisms by which P. pachyrhizi and other rust fungi interact with their host plants are poorly understood. The genomes of all rust fungi encode many small, secreted cysteine-rich proteins (SSCRP). While these proteins are thought to function within the host, their roles are completely unknown. Here, we present the characterization of P. pachyrhizi effector candidate 23 (PpEC23), a SSCRP that we show to suppress plant immunity. Furthermore, we show that PpEC23 interacts with soybean transcription factor GmSPL12l and that soybean plants in which GmSPL12l is silenced have constitutively active immunity, thereby identifying GmSPL12l as a negative regulator of soybean defenses. Collectively, our data present evidence for a virulence function of a rust SSCRP and suggest that PpEC23 is able to suppress soybean immune responses and physically interact with soybean transcription factor GmSPL12l, a negative immune regulator. PMID:27676173

  19. Ralstonia solanacearum Type III Effector RipAY Is a Glutathione-Degrading Enzyme That Is Activated by Plant Cytosolic Thioredoxins and Suppresses Plant Immunity

    PubMed Central

    Hatanaka, Tadashi; Nakano, Masahito; Oda, Kenji

    2016-01-01

    ABSTRACT The plant pathogen Ralstonia solanacearum uses a large repertoire of type III effector proteins to succeed in infection. To clarify the function of effector proteins in host eukaryote cells, we expressed effectors in yeast cells and identified seven effector proteins that interfere with yeast growth. One of the effector proteins, RipAY, was found to share homology with the ChaC family proteins that function as γ-glutamyl cyclotransferases, which degrade glutathione (GSH), a tripeptide that plays important roles in the plant immune system. RipAY significantly inhibited yeast growth and simultaneously induced rapid GSH depletion when expressed in yeast cells. The in vitro GSH degradation activity of RipAY is specifically activated by eukaryotic factors in the yeast and plant extracts. Biochemical purification of the yeast protein identified that RipAY is activated by thioredoxin TRX2. On the other hand, RipAY was not activated by bacterial thioredoxins. Interestingly, RipAY was activated by plant h-type thioredoxins that exist in large amounts in the plant cytosol, but not by chloroplastic m-, f-, x-, y- and z-type thioredoxins, in a thiol-independent manner. The transient expression of RipAY decreased the GSH level in plant cells and affected the flg22-triggered production of reactive oxygen species (ROS) and expression of pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) marker genes in Nicotiana benthamiana leaves. These results indicate that RipAY is activated by host cytosolic thioredoxins and degrades GSH specifically in plant cells to suppress plant immunity. PMID:27073091

  20. The bifunctional plant receptor, OsCERK1, regulates both chitin-triggered immunity and arbuscular mycorrhizal symbiosis in rice.

    PubMed

    Miyata, Kana; Kozaki, Toshinori; Kouzai, Yusuke; Ozawa, Kenjirou; Ishii, Kazuo; Asamizu, Erika; Okabe, Yoshihiro; Umehara, Yosuke; Miyamoto, Ayano; Kobae, Yoshihiro; Akiyama, Kohki; Kaku, Hanae; Nishizawa, Yoko; Shibuya, Naoto; Nakagawa, Tomomi

    2014-11-01

    Plants are constantly exposed to threats from pathogenic microbes and thus developed an innate immune system to protect themselves. On the other hand, many plants also have the ability to establish endosymbiosis with beneficial microbes such as arbuscular mycorrhizal (AM) fungi or rhizobial bacteria, which improves the growth of host plants. How plants evolved these systems managing such opposite plant-microbe interactions is unclear. We show here that knockout (KO) mutants of OsCERK1, a rice receptor kinase essential for chitin signaling, were impaired not only for chitin-triggered defense responses but also for AM symbiosis, indicating the bifunctionality of OsCERK1 in defense and symbiosis. On the other hand, a KO mutant of OsCEBiP, which forms a receptor complex with OsCERK1 and is essential for chitin-triggered immunity, established mycorrhizal symbiosis normally. Therefore, OsCERK1 but not chitin-triggered immunity is required for AM symbiosis. Furthermore, experiments with chimeric receptors showed that the kinase domains of OsCERK1 and homologs from non-leguminous, mycorrhizal plants could trigger nodulation signaling in legume-rhizobium interactions as the kinase domain of Nod factor receptor1 (NFR1), which is essential for triggering the nodulation program in leguminous plants, did. Because leguminous plants are believed to have developed the rhizobial symbiosis on the basis of AM symbiosis, our results suggest that the symbiotic function of ancestral CERK1 in AM symbiosis enabled the molecular evolution to leguminous NFR1 and resulted in the establishment of legume-rhizobia symbiosis. These results also suggest that OsCERK1 and homologs serve as a molecular switch that activates defense or symbiotic responses depending on the infecting microbes. PMID:25231970

  1. The bifunctional plant receptor, OsCERK1, regulates both chitin-triggered immunity and arbuscular mycorrhizal symbiosis in rice.

    PubMed

    Miyata, Kana; Kozaki, Toshinori; Kouzai, Yusuke; Ozawa, Kenjirou; Ishii, Kazuo; Asamizu, Erika; Okabe, Yoshihiro; Umehara, Yosuke; Miyamoto, Ayano; Kobae, Yoshihiro; Akiyama, Kohki; Kaku, Hanae; Nishizawa, Yoko; Shibuya, Naoto; Nakagawa, Tomomi

    2014-11-01

    Plants are constantly exposed to threats from pathogenic microbes and thus developed an innate immune system to protect themselves. On the other hand, many plants also have the ability to establish endosymbiosis with beneficial microbes such as arbuscular mycorrhizal (AM) fungi or rhizobial bacteria, which improves the growth of host plants. How plants evolved these systems managing such opposite plant-microbe interactions is unclear. We show here that knockout (KO) mutants of OsCERK1, a rice receptor kinase essential for chitin signaling, were impaired not only for chitin-triggered defense responses but also for AM symbiosis, indicating the bifunctionality of OsCERK1 in defense and symbiosis. On the other hand, a KO mutant of OsCEBiP, which forms a receptor complex with OsCERK1 and is essential for chitin-triggered immunity, established mycorrhizal symbiosis normally. Therefore, OsCERK1 but not chitin-triggered immunity is required for AM symbiosis. Furthermore, experiments with chimeric receptors showed that the kinase domains of OsCERK1 and homologs from non-leguminous, mycorrhizal plants could trigger nodulation signaling in legume-rhizobium interactions as the kinase domain of Nod factor receptor1 (NFR1), which is essential for triggering the nodulation program in leguminous plants, did. Because leguminous plants are believed to have developed the rhizobial symbiosis on the basis of AM symbiosis, our results suggest that the symbiotic function of ancestral CERK1 in AM symbiosis enabled the molecular evolution to leguminous NFR1 and resulted in the establishment of legume-rhizobia symbiosis. These results also suggest that OsCERK1 and homologs serve as a molecular switch that activates defense or symbiotic responses depending on the infecting microbes.

  2. Structural characterization of antibiotic self-immunity tRNA synthetase in plant tumour biocontrol agent

    PubMed Central

    Chopra, Shaileja; Palencia, Andrés; Virus, Cornelia; Schulwitz, Sarah; Temple, Brenda R.; Cusack, Stephen; Reader, John

    2016-01-01

    Antibiotic-producing microbes evolved self-resistance mechanisms to avoid suicide. The biocontrol Agrobacterium radiobacter K84 secretes the Trojan Horse antibiotic agrocin 84 that is selectively transported into the plant pathogen A. tumefaciens and processed into the toxin TM84. We previously showed that TM84 employs a unique tRNA-dependent mechanism to inhibit leucyl-tRNA synthetase (LeuRS), while the TM84-producer prevents self-poisoning by expressing a resistant LeuRS AgnB2. We now identify a mechanism by which the antibiotic-producing microbe resists its own toxin. Using a combination of structural, biochemical and biophysical approaches, we show that AgnB2 evolved structural changes so as to resist the antibiotic by eliminating the tRNA-dependence of TM84 binding. Mutagenesis of key resistance determinants results in mutants adopting an antibiotic-sensitive phenotype. This study illuminates the evolution of resistance in self-immunity genes and provides mechanistic insights into a fascinating tRNA-dependent antibiotic with applications for the development of anti-infectives and the prevention of biocontrol emasculation. PMID:27713402

  3. A Plasmodium-like virulence effector of the soybean cyst nematode suppresses plant innate immunity.

    PubMed

    Noon, Jason B; Qi, Mingsheng; Sill, Danielle N; Muppirala, Usha; Eves-van den Akker, Sebastian; Maier, Thomas R; Dobbs, Drena; Mitchum, Melissa G; Hewezi, Tarek; Baum, Thomas J

    2016-10-01

    Heterodera glycines, the soybean cyst nematode, delivers effector proteins into soybean roots to initiate and maintain an obligate parasitic relationship. HgGLAND18 encodes a candidate H. glycines effector and is expressed throughout the infection process. We used a combination of molecular, genetic, bioinformatic and phylogenetic analyses to determine the role of HgGLAND18 during H. glycines infection. HgGLAND18 is necessary for pathogenicity in compatible interactions with soybean. The encoded effector strongly suppresses both basal and hypersensitive cell death innate immune responses, and immunosuppression requires the presence and coordination between multiple protein domains. The N-terminal domain in HgGLAND18 contains unique sequence similarity to domains of an immunosuppressive effector of Plasmodium spp., the malaria parasites. The Plasmodium effector domains functionally complement the loss of the N-terminal domain from HgGLAND18. In-depth sequence searches and phylogenetic analyses demonstrate convergent evolution between effectors from divergent parasites of plants and animals as the cause of sequence and functional similarity. PMID:27265684

  4. A pair of light signaling factors FHY3 and FAR1 regulates plant immunity by modulating chlorophyll biosynthesis.

    PubMed

    Wang, Wanqing; Tang, Weijiang; Ma, Tingting; Niu, De; Jin, Jing Bo; Wang, Haiyang; Lin, Rongcheng

    2016-01-01

    Light and chloroplast function is known to affect the plant immune response; however, the underlying mechanism remains elusive. We previously demonstrated that two light signaling factors, FAR-RED ELONGATED HYPOCOTYL 3 (FHY3) and FAR-RED IMPAIRED RESPONSE 1 (FAR1), regulate chlorophyll biosynthesis and seedling growth via controlling HEMB1 expression in Arabidopsis thaliana. In this study, we reveal that FHY3 and FAR1 are involved in modulating plant immunity. We showed that the fhy3 far1 double null mutant displayed high levels of reactive oxygen species and salicylic acid (SA) and increased resistance to Pseudomonas syringae pathogen infection. Microarray analysis revealed that a large proportion of pathogen-related genes, particularly genes encoding nucleotide-binding and leucine-rich repeat domain resistant proteins, are highly induced in fhy3 far1. Genetic studies indicated that the defects of fhy3 far1 can be largely rescued by reducing SA signaling or blocking SA accumulation, and by overexpression of HEMB1, which encodes a 5-aminolevulinic acid dehydratase in the chlorophyll biosynthetic pathway. Furthermore, we found that transgenic plants with reduced expression of HEMB1 exhibit a phenotype similar to fhy3 far1. Taken together, this study demonstrates an important role of FHY3 and FAR1 in regulating plant immunity, through integrating chlorophyll biosynthesis and the SA signaling pathway.

  5. Host plant quality, selection history and trade-offs shape the immune responses of Manduca sexta.

    PubMed

    Diamond, Sarah E; Kingsolver, Joel G

    2011-01-22

    Immune defences are an important component of fitness. Yet susceptibility to pathogens is common, suggesting the presence of ecological and evolutionary limitations on immune defences. Here, we use structural equation modelling to quantify the direct effects of resource quality and selection history, and their indirect effects mediated via body condition prior to an immune challenge on encapsulation and melanization immune defences in the tobacco hornworm, Manduca sexta. We also investigate allocation trade-offs among immune defences and growth rate following an immune challenge. We found considerable variation in the magnitude and direction of the direct effects of resource quality and selection history on immune defences and their indirect effects mediated via body condition and allocation trade-offs. Greater resource quality and evolutionary exposure to pathogens had positive direct effects on encapsulation and melanization. The indirect effect of resource quality on encapsulation mediated via body condition was substantial, whereas indirect effects on melanization were negligible. Individuals in better condition prior to the immune challenge had greater encapsulation; however, following the immune challenge, greater encapsulation traded off with slower growth rate. Our study demonstrates the importance of experimentally and analytically disentangling the relative contributions of direct and indirect effects to understand variation in immune defences.

  6. IRE1/bZIP60-Mediated Unfolded Protein Response Plays Distinct Roles in Plant Immunity and Abiotic Stress Responses

    PubMed Central

    Blanco, Francisca; Boatwright, Jon Lucas; Moreno, Ignacio; Jordan, Melissa R.; Chen, Yani; Brandizzi, Federica; Dong, Xinnian

    2012-01-01

    Endoplasmic reticulum (ER)-mediated protein secretion and quality control have been shown to play an important role in immune responses in both animals and plants. In mammals, the ER membrane-located IRE1 kinase/endoribonuclease, a key regulator of unfolded protein response (UPR), is required for plasma cell development to accommodate massive secretion of immunoglobulins. Plant cells can secrete the so-called pathogenesis-related (PR) proteins with antimicrobial activities upon pathogen challenge. However, whether IRE1 plays any role in plant immunity is not known. Arabidopsis thaliana has two copies of IRE1, IRE1a and IRE1b. Here, we show that both IRE1a and IRE1b are transcriptionally induced during chemically-induced ER stress, bacterial pathogen infection and treatment with the immune signal salicylic acid (SA). However, we found that IRE1a plays a predominant role in the secretion of PR proteins upon SA treatment. Consequently, the ire1a mutant plants show enhanced susceptibility to a bacterial pathogen and are deficient in establishing systemic acquired resistance (SAR), whereas ire1b is unaffected in these responses. We further demonstrate that the immune deficiency in ire1a is due to a defect in SA- and pathogen-triggered, IRE1-mediated cytoplasmic splicing of the bZIP60 mRNA, which encodes a transcription factor involved in the expression of UPR-responsive genes. Consistently, IRE1a is preferentially required for bZIP60 splicing upon pathogen infection, while IRE1b plays a major role in bZIP60 processing upon Tunicamycin (Tm)-induced stress. We also show that SA-dependent induction of UPR-responsive genes is altered in the bzip60 mutant resulting in a moderate susceptibility to a bacterial pathogen. These results indicate that the IRE1/bZIP60 branch of UPR is a part of the plant response to pathogens for which the two Arabidopsis IRE1 isoforms play only partially overlapping roles and that IRE1 has both bZIP60-dependent and bZIP60-independent functions in

  7. Surface α-1,3-glucan facilitates fungal stealth infection by interfering with innate immunity in plants.

    PubMed

    Fujikawa, Takashi; Sakaguchi, Ayumu; Nishizawa, Yoko; Kouzai, Yusuke; Minami, Eiichi; Yano, Shigekazu; Koga, Hironori; Meshi, Tetsuo; Nishimura, Marie

    2012-01-01

    Plants evoke innate immunity against microbial challenges upon recognition of pathogen-associated molecular patterns (PAMPs), such as fungal cell wall chitin. Nevertheless, pathogens may circumvent the host PAMP-triggered immunity. We previously reported that the ascomycete Magnaporthe oryzae, a famine-causing rice pathogen, masks cell wall surfaces with α-1,3-glucan during invasion. Here, we show that the surface α-1,3-glucan is indispensable for the successful infection of the fungus by interfering with the plant's defense mechanisms. The α-1,3-glucan synthase gene MgAGS1 was not essential for infectious structure development but was required for infection in M. oryzae. Lack or degradation of surface α-1,3-glucan increased fungal susceptibility towards chitinase, suggesting the protective role of α-1,3-glucan against plants' antifungal enzymes during infection. Furthermore, rice plants secreting bacterial α-1,3-glucanase (AGL-rice) showed strong resistance not only to M. oryzae but also to the phylogenetically distant ascomycete Cochlioborus miyabeanus and the polyphagous basidiomycete Rhizoctonia solani; the histocytochemical analysis of the latter two revealed that α-1,3-glucan also concealed cell wall chitin in an infection-specific manner. Treatment with α-1,3-glucanase in vitro caused fragmentation of infectious hyphae in R. solani but not in M. oryzae or C. miyabeanus, indicating that α-1,3-glucan is also involved in maintaining infectious structures in some fungi. Importantly, rapid defense responses were evoked (a few hours after inoculation) in the AGL-rice inoculated with M. oryzae, C. miyabeanus and R. solani as well as in non-transgenic rice inoculated with the ags1 mutant. Taken together, our results suggest that α-1,3-glucan protected the fungal cell wall from degradative enzymes secreted by plants even from the pre-penetration stage and interfered with the release of PAMPs to delay innate immune defense responses. Because α-1,3-glucan is

  8. Biochemical characterization of the tomato phosphatidylinositol-specific phospholipase C (PI-PLC) family and its role in plant immunity.

    PubMed

    Abd-El-Haliem, Ahmed M; Vossen, Jack H; van Zeijl, Arjan; Dezhsetan, Sara; Testerink, Christa; Seidl, Michael F; Beck, Martina; Strutt, James; Robatzek, Silke; Joosten, Matthieu H A J

    2016-09-01

    Plants possess effective mechanisms to quickly respond to biotic and abiotic stresses. The rapid activation of phosphatidylinositol-specific phospholipase C (PLC) enzymes occurs early after the stimulation of plant immune-receptors. Genomes of different plant species encode multiple PLC homologs belonging to one class, PLCζ. Here we determined whether all tomato homologs encode active enzymes and whether they can generate signals that are distinct from one another. We searched the recently completed tomato (Solanum lycopersicum) genome sequence and identified a total of seven PLCs. Recombinant proteins were produced for all tomato PLCs, except for SlPLC7. The purified proteins showed typical PLC activity, as different PLC substrates were hydrolysed to produce diacylglycerol. We studied SlPLC2, SlPLC4 and SlPLC5 enzymes in more detail and observed distinct requirements for Ca(2+) ions and pH, for both their optimum activity and substrate preference. This indicates that each enzyme could be differentially and specifically regulated in vivo, leading to the generation of PLC homolog-specific signals in response to different stimuli. PLC overexpression and specific inhibition of PLC activity revealed that PLC is required for both specific effector- and more general "pattern"-triggered immunity. For the latter, we found that both the flagellin-triggered response and the internalization of the corresponding receptor, Flagellin Sensing 2 (FLS2) of Arabidopsis thaliana, are suppressed by inhibition of PLC activity. Altogether, our data support an important role for PLC enzymes in plant defence signalling downstream of immune receptors. This article is part of a Special Issue entitled: Plant Lipid Biology edited by Kent D. Chapman and Ivo Feussner.

  9. Biochemical characterization of the tomato phosphatidylinositol-specific phospholipase C (PI-PLC) family and its role in plant immunity.

    PubMed

    Abd-El-Haliem, Ahmed M; Vossen, Jack H; van Zeijl, Arjan; Dezhsetan, Sara; Testerink, Christa; Seidl, Michael F; Beck, Martina; Strutt, James; Robatzek, Silke; Joosten, Matthieu H A J

    2016-09-01

    Plants possess effective mechanisms to quickly respond to biotic and abiotic stresses. The rapid activation of phosphatidylinositol-specific phospholipase C (PLC) enzymes occurs early after the stimulation of plant immune-receptors. Genomes of different plant species encode multiple PLC homologs belonging to one class, PLCζ. Here we determined whether all tomato homologs encode active enzymes and whether they can generate signals that are distinct from one another. We searched the recently completed tomato (Solanum lycopersicum) genome sequence and identified a total of seven PLCs. Recombinant proteins were produced for all tomato PLCs, except for SlPLC7. The purified proteins showed typical PLC activity, as different PLC substrates were hydrolysed to produce diacylglycerol. We studied SlPLC2, SlPLC4 and SlPLC5 enzymes in more detail and observed distinct requirements for Ca(2+) ions and pH, for both their optimum activity and substrate preference. This indicates that each enzyme could be differentially and specifically regulated in vivo, leading to the generation of PLC homolog-specific signals in response to different stimuli. PLC overexpression and specific inhibition of PLC activity revealed that PLC is required for both specific effector- and more general "pattern"-triggered immunity. For the latter, we found that both the flagellin-triggered response and the internalization of the corresponding receptor, Flagellin Sensing 2 (FLS2) of Arabidopsis thaliana, are suppressed by inhibition of PLC activity. Altogether, our data support an important role for PLC enzymes in plant defence signalling downstream of immune receptors. This article is part of a Special Issue entitled: Plant Lipid Biology edited by Kent D. Chapman and Ivo Feussner. PMID:26825689

  10. Phosphorylation of the Plant Immune Regulator RPM1-INTERACTING PROTEIN4 Enhances Plant Plasma Membrane H+-ATPase Activity and Inhibits Flagellin-Triggered Immune Responses in Arabidopsis[OPEN

    PubMed Central

    Lee, DongHyuk; Bourdais, Gildas; Yu, Gang; Robatzek, Silke; Coaker, Gitta

    2015-01-01

    The Pseudomonas syringae effector AvrB targets multiple host proteins during infection, including the plant immune regulator RPM1-INTERACTING PROTEIN4 (RIN4) and RPM1-INDUCED PROTEIN KINASE (RIPK). In the presence of AvrB, RIPK phosphorylates RIN4 at Thr-21, Ser-160, and Thr-166, leading to activation of the immune receptor RPM1. Here, we investigated the role of RIN4 phosphorylation in susceptible Arabidopsis thaliana genotypes. Using circular dichroism spectroscopy, we show that RIN4 is a disordered protein and phosphorylation affects protein flexibility. RIN4 T21D/S160D/T166D phosphomimetic mutants exhibited enhanced disease susceptibility upon surface inoculation with P. syringae, wider stomatal apertures, and enhanced plasma membrane H+-ATPase activity. The plasma membrane H+-ATPase AHA1 is highly expressed in guard cells, and its activation can induce stomatal opening. The ripk knockout also exhibited a strong defect in pathogen-induced stomatal opening. The basal level of RIN4 Thr-166 phosphorylation decreased in response to immune perception of bacterial flagellin. RIN4 Thr166D lines exhibited reduced flagellin-triggered immune responses. Flagellin perception did not lower RIN4 Thr-166 phosphorylation in the presence of strong ectopic expression of AvrB. Taken together, these results indicate that the AvrB effector targets RIN4 in order to enhance pathogen entry on the leaf surface as well as dampen responses to conserved microbial features. PMID:26198070

  11. Modulation of Root Microbiome Community Assembly by the Plant Immune Response (2013 DOE JGI Genomics of Energy and Environment 8th Annual User Meeting)

    SciTech Connect

    Lebeis, Sarah

    2013-03-01

    Sarah Lebeis of University of North Carolina on "Modulation of root microbiome community assembly by the plant immune response" at the 8th Annual Genomics of Energy & Environment Meeting on March 28, 2013 in Walnut Creek, Calif.

  12. Sulfonamides identified as plant immune-priming compounds in high-throughput chemical screening increase disease resistance in Arabidopsis thaliana

    PubMed Central

    Noutoshi, Yoshiteru; Ikeda, Mika; Saito, Tamio; Osada, Hiroyuki; Shirasu, Ken

    2012-01-01

    Plant activators are agrochemicals that protect crops from diseases by activating the plant immune system. To isolate lead compounds for use as practical plant activators, we screened two different chemical libraries composed of various bioactive substances by using an established screening procedure that can selectively identify immune-priming compounds. We identified and characterized a group of sulfonamide compounds – sulfameter, sulfamethoxypyridazine, sulfabenzamide, and sulfachloropyridazine – among the various isolated candidate molecules. These sulfonamide compounds enhanced the avirulent Pseudomonas-induced cell death of Arabidopsis suspension cell cultures and increased disease resistance in Arabidopsis plants against both avirulent and virulent strains of the bacterium. These compounds did not prevent the growth of pathogenic bacteria in minimal liquid media at 200 μM. They also did not induce the expression of defense-related genes in Arabidopsis seedlings, at least not at 24 and 48 h after treatment, suggesting that they do not act as salicylic acid analogs. In addition, although sulfonamides are known to be folate biosynthesis inhibitors, the application of folate did not restore the potentiation effects of the sulfonamides on pathogen-induced cell death. Our data suggest that sulfonamides potentiate Arabidopsis disease resistance by their novel chemical properties. PMID:23118736

  13. Balanced nuclear and cytoplasmic activities of EDS1 are required for a complete plant innate immune response.

    PubMed

    García, Ana V; Blanvillain-Baufumé, Servane; Huibers, Robin P; Wiermer, Marcel; Li, Guangyong; Gobbato, Enrico; Rietz, Steffen; Parker, Jane E

    2010-07-01

    An important layer of plant innate immunity to host-adapted pathogens is conferred by intracellular nucleotide-binding/oligomerization domain-leucine rich repeat (NB-LRR) receptors recognizing specific microbial effectors. Signaling from activated receptors of the TIR (Toll/Interleukin-1 Receptor)-NB-LRR class converges on the nucleo-cytoplasmic immune regulator EDS1 (Enhanced Disease Susceptibility1). In this report we show that a receptor-stimulated increase in accumulation of nuclear EDS1 precedes or coincides with the EDS1-dependent induction and repression of defense-related genes. EDS1 is capable of nuclear transport receptor-mediated shuttling between the cytoplasm and nucleus. By enhancing EDS1 export from inside nuclei (through attachment of an additional nuclear export sequence (NES)) or conditionally releasing EDS1 to the nucleus (by fusion to a glucocorticoid receptor (GR)) in transgenic Arabidopsis we establish that the EDS1 nuclear pool is essential for resistance to biotrophic and hemi-biotrophic pathogens and for transcriptional reprogramming. Evidence points to post-transcriptional processes regulating receptor-triggered accumulation of EDS1 in nuclei. Changes in nuclear EDS1 levels become equilibrated with the cytoplasmic EDS1 pool and cytoplasmic EDS1 is needed for complete resistance and restriction of host cell death at infection sites. We propose that coordinated nuclear and cytoplasmic activities of EDS1 enable the plant to mount an appropriately balanced immune response to pathogen attack.

  14. WRKY Transcription Factors Phosphorylated by MAPK Regulate a Plant Immune NADPH Oxidase in Nicotiana benthamiana[OPEN

    PubMed Central

    Adachi, Hiroaki; Nakano, Takaaki; Miyagawa, Noriko; Ishihama, Nobuaki; Yoshioka, Miki; Katou, Yuri; Yaeno, Takashi

    2015-01-01

    Pathogen attack sequentially confers pattern-triggered immunity (PTI) and effector-triggered immunity (ETI) after sensing of pathogen patterns and effectors by plant immune receptors, respectively. Reactive oxygen species (ROS) play pivotal roles in PTI and ETI as signaling molecules. Nicotiana benthamiana RBOHB, an NADPH oxidase, is responsible for both the transient PTI ROS burst and the robust ETI ROS burst. Here, we show that RBOHB transactivation mediated by MAPK contributes to R3a/AVR3a-triggered ETI (AVR3a-ETI) ROS burst. RBOHB is markedly induced during the ETI and INF1-triggered PTI (INF1-PTI), but not flg22-tiggered PTI (flg22-PTI). We found that the RBOHB promoter contains a functional W-box in the R3a/AVR3a and INF1 signal-responsive cis-element. Ectopic expression of four phospho-mimicking mutants of WRKY transcription factors, which are MAPK substrates, induced RBOHB, and yeast one-hybrid analysis indicated that these mutants bind to the cis-element. Chromatin immunoprecipitation assays indicated direct binding of the WRKY to the cis-element in plants. Silencing of multiple WRKY genes compromised the upregulation of RBOHB, resulting in impairment of AVR3a-ETI and INF1-PTI ROS bursts, but not the flg22-PTI ROS burst. These results suggest that the MAPK-WRKY pathway is required for AVR3a-ETI and INF1-PTI ROS bursts by activation of RBOHB. PMID:26373453

  15. A receptor-like cytoplasmic kinase, BIK1, associates with a flagellin receptor complex to initiate plant innate immunity

    PubMed Central

    Lu, Dongping; Wu, Shujing; Gao, Xiquan; Zhang, Yulan; Shan, Libo; He, Ping

    2010-01-01

    Plants and animals rely on innate immunity to prevent infections by detection of microbe-associated molecular patterns (MAMPs) through pattern-recognition receptors (PRRs). The plant PRR FLS2, a leucine-rich repeat-receptor kinase, recognizes bacterial flagellin and initiates immune signaling by association with another leucine-rich repeat-receptor-like kinase, BAK1. It remains unknown how the FLS2/BAK1 receptor complex activates intracellular signaling cascades. Here we identified the receptor-like cytoplasmic kinase BIK1 that is rapidly phosphorylated upon flagellin perception, depending on both FLS2 and BAK1. BIK1 associates with FLS2 and BAK1 in vivo and in vitro. BIK1 is phosphorylated by BAK1, and BIK1 also directly phosphorylates BAK1 and FLS2 in vitro. The flagellin phosphorylation site Thr237 of BIK1 is required for its phosphorylation on BAK1 and FLS2, suggesting that BIK1 is likely first phosphorylated upon flagellin perception and subsequently transphosphorylates FLS2/BAK1 to propagate flagellin signaling. Importantly, bik1 mutants are compromised in diverse flagellin-mediated responses and immunity to the nonpathogenic bacterial infection. Thus, BIK1 is an essential component in MAMP signal transduction, which links the MAMP receptor complex to downstream intracellular signaling. PMID:20018686

  16. Balanced Nuclear and Cytoplasmic Activities of EDS1 Are Required for a Complete Plant Innate Immune Response

    PubMed Central

    García, Ana V.; Blanvillain-Baufumé, Servane; Huibers, Robin P.; Wiermer, Marcel; Li, Guangyong; Gobbato, Enrico; Rietz, Steffen; Parker, Jane E.

    2010-01-01

    An important layer of plant innate immunity to host-adapted pathogens is conferred by intracellular nucleotide-binding/oligomerization domain-leucine rich repeat (NB-LRR) receptors recognizing specific microbial effectors. Signaling from activated receptors of the TIR (Toll/Interleukin-1 Receptor)-NB-LRR class converges on the nucleo-cytoplasmic immune regulator EDS1 (Enhanced Disease Susceptibility1). In this report we show that a receptor-stimulated increase in accumulation of nuclear EDS1 precedes or coincides with the EDS1-dependent induction and repression of defense-related genes. EDS1 is capable of nuclear transport receptor-mediated shuttling between the cytoplasm and nucleus. By enhancing EDS1 export from inside nuclei (through attachment of an additional nuclear export sequence (NES)) or conditionally releasing EDS1 to the nucleus (by fusion to a glucocorticoid receptor (GR)) in transgenic Arabidopsis we establish that the EDS1 nuclear pool is essential for resistance to biotrophic and hemi-biotrophic pathogens and for transcriptional reprogramming. Evidence points to post-transcriptional processes regulating receptor-triggered accumulation of EDS1 in nuclei. Changes in nuclear EDS1 levels become equilibrated with the cytoplasmic EDS1 pool and cytoplasmic EDS1 is needed for complete resistance and restriction of host cell death at infection sites. We propose that coordinated nuclear and cytoplasmic activities of EDS1 enable the plant to mount an appropriately balanced immune response to pathogen attack. PMID:20617163

  17. BR-SIGNALING KINASE1 Physically Associates with FLAGELLIN SENSING2 and Regulates Plant Innate Immunity in Arabidopsis[W

    PubMed Central

    Shi, Hua; Shen, Qiujing; Qi, Yiping; Yan, Haojie; Nie, Haozhen; Chen, Yongfang; Zhao, Ting; Katagiri, Fumiaki; Tang, Dingzhong

    2013-01-01

    Pathogen-associated molecular pattern (PAMP)-trigged immunity (PTI) is the first defensive line of plant innate immunity and is mediated by pattern recognition receptors. Here, we show that a mutation in BR-SIGNALING KINASE1 (BSK1), a substrate of the brassinosteroid (BR) receptor BRASSINOSTEROID INSENSITIVE1, suppressed the powdery mildew resistance caused by a mutation in ENHANCED DISEASE RESISTANCE2, which negatively regulates powdery mildew resistance and programmed cell death, in Arabidopsis thaliana. A loss-of-function bsk1 mutant displayed enhanced susceptibility to virulent and avirulent pathogens, including Golovinomyces cichoracearum, Pseudomonas syringae, and Hyaloperonospora arabidopsidis. The bsk1 mutant also accumulated lower levels of salicylic acid upon infection with G. cichoracearum and P. syringae. BSK1 belongs to a receptor-like cytoplasmic kinase family and displays kinase activity in vitro; this kinase activity is required for its function. BSK1 physically associates with the PAMP receptor FLAGELLIN SENSING2 and is required for a subset of flg22-induced responses, including the reactive oxygen burst, but not for mitogen-activated protein kinase activation. Our data demonstrate that BSK1 is involved in positive regulation of PTI. Together with previous findings, our work indicates that BSK1 represents a key component directly involved in both BR signaling and plant immunity. PMID:23532072

  18. Linking ligand perception by PEPR pattern recognition receptors to cytosolic Ca2+ elevation and downstream immune signaling in plants

    PubMed Central

    Walker, Robin K.; Zhao, Yichen; Berkowitz, Gerald A.

    2012-01-01

    Little is known about molecular steps linking perception of pathogen invasion by cell surface sentry proteins acting as pattern recognition receptors (PRRs) to downstream cytosolic Ca2+ elevation, a critical step in plant immune signaling cascades. Some PRRs recognize molecules (such as flagellin) associated with microbial pathogens (pathogen-associated molecular patterns, PAMPs), whereas others bind endogenous plant compounds (damage-associated molecular patterns, DAMPs) such as peptides released from cells upon attack. This work focuses on the Arabidopsis DAMPs plant elicitor peptides (Peps) and their receptors, PEPR1 and PEPR2. Pep application causes in vivo cGMP generation and downstream signaling that is lost when the predicted PEPR receptor guanylyl cyclase (GC) active site is mutated. Pep-induced Ca2+ elevation is attributable to cGMP activation of a Ca2+ channel. Some differences were identified between Pep/PEPR signaling and the Ca2+-dependent immune signaling initiated by the flagellin peptide flg22 and its cognate receptor Flagellin-sensing 2 (FLS2). FLS2 signaling may have a greater requirement for intracellular Ca2+ stores and inositol phosphate signaling, whereas Pep/PEPR signaling requires extracellular Ca2+. Maximal FLS2 signaling requires a functional Pep/PEPR system. This dependence was evidenced as a requirement for functional PEPR receptors for maximal flg22-dependent Ca2+ elevation, H2O2 generation, defense gene [WRKY33 and Plant Defensin 1.2 (PDF1.2)] expression, and flg22/FLS2-dependent impairment of pathogen growth. In a corresponding fashion, FLS2 loss of function impaired Pep signaling. In addition, a role for PAMP and DAMP perception in bolstering effector-triggered immunity (ETI) is reported; loss of function of either FLS2 or PEPR receptors impaired the hypersensitive response (HR) to an avirulent pathogen. PMID:23150556

  19. Linking ligand perception by PEPR pattern recognition receptors to cytosolic Ca2+ elevation and downstream immune signaling in plants.

    PubMed

    Ma, Yi; Walker, Robin K; Zhao, Yichen; Berkowitz, Gerald A

    2012-11-27

    Little is known about molecular steps linking perception of pathogen invasion by cell surface sentry proteins acting as pattern recognition receptors (PRRs) to downstream cytosolic Ca(2+) elevation, a critical step in plant immune signaling cascades. Some PRRs recognize molecules (such as flagellin) associated with microbial pathogens (pathogen-associated molecular patterns, PAMPs), whereas others bind endogenous plant compounds (damage-associated molecular patterns, DAMPs) such as peptides released from cells upon attack. This work focuses on the Arabidopsis DAMPs plant elicitor peptides (Peps) and their receptors, PEPR1 and PEPR2. Pep application causes in vivo cGMP generation and downstream signaling that is lost when the predicted PEPR receptor guanylyl cyclase (GC) active site is mutated. Pep-induced Ca(2+) elevation is attributable to cGMP activation of a Ca(2+) channel. Some differences were identified between Pep/PEPR signaling and the Ca(2+)-dependent immune signaling initiated by the flagellin peptide flg22 and its cognate receptor Flagellin-sensing 2 (FLS2). FLS2 signaling may have a greater requirement for intracellular Ca(2+) stores and inositol phosphate signaling, whereas Pep/PEPR signaling requires extracellular Ca(2+). Maximal FLS2 signaling requires a functional Pep/PEPR system. This dependence was evidenced as a requirement for functional PEPR receptors for maximal flg22-dependent Ca(2+) elevation, H(2)O(2) generation, defense gene [WRKY33 and Plant Defensin 1.2 (PDF1.2)] expression, and flg22/FLS2-dependent impairment of pathogen growth. In a corresponding fashion, FLS2 loss of function impaired Pep signaling. In addition, a role for PAMP and DAMP perception in bolstering effector-triggered immunity (ETI) is reported; loss of function of either FLS2 or PEPR receptors impaired the hypersensitive response (HR) to an avirulent pathogen.

  20. Transcriptomics-based screen for genes induced by flagellin and repressed by pathogen effectors identifies a cell wall-associated kinase involved in plant immunity

    PubMed Central

    2013-01-01

    Background Microbe-associated molecular patterns, such as those present in bacterial flagellin, are powerful inducers of the innate immune response in plants. Successful pathogens deliver virulence proteins, termed effectors, into the plant cell where they can interfere with the immune response and promote disease. Engineering the plant immune system to enhance disease resistance requires a thorough understanding of its components. Results We describe a high-throughput screen, using RNA sequencing and virus-induced gene silencing, to identify tomato genes whose expression is enhanced by the flagellin microbe-associated molecular pattern flgII-28, but reduced by activities of the Pseudomonas syringae pv. tomato (Pst) type III effectors AvrPto and AvrPtoB. Gene ontology terms for this category of Flagellin-induced repressed by effectors (FIRE) genes showed enrichment for genes encoding certain subfamilies of protein kinases and transcription factors. At least 25 of the FIRE genes have been implicated previously in plant immunity. Of the 92 protein kinase-encoding FIRE genes, 33 were subjected to virus-induced gene silencing and their involvement in pattern-triggered immunity was tested with a leaf-based assay. Silencing of one FIRE gene, which encodes the cell wall-associated kinase SlWAK1, compromised the plant immune response resulting in increased growth of Pst and enhanced disease symptoms. Conclusions Our transcriptomic approach identifies FIRE genes that represent a pathogen-defined core set of immune-related genes. The analysis of this set of candidate genes led to the discovery of a cell wall-associated kinase that participates in plant defense. The FIRE genes will be useful for further elucidation of the plant immune system. PMID:24359686

  1. Receptor-like kinase SOBIR1/EVR interacts with receptor-like proteins in plant immunity against fungal infection.

    PubMed

    Liebrand, Thomas W H; van den Berg, Grardy C M; Zhang, Zhao; Smit, Patrick; Cordewener, Jan H G; America, Antoine H P; America, Antione H P; Sklenar, Jan; Jones, Alexandra M E; Tameling, Wladimir I L; Robatzek, Silke; Thomma, Bart P H J; Joosten, Matthieu H A J

    2013-06-11

    The plant immune system is activated by microbial patterns that are detected as nonself molecules. Such patterns are recognized by immune receptors that are cytoplasmic or localized at the plasma membrane. Cell surface receptors are represented by receptor-like kinases (RLKs) that frequently contain extracellular leucine-rich repeats and an intracellular kinase domain for activation of downstream signaling, as well as receptor-like proteins (RLPs) that lack this signaling domain. It is therefore hypothesized that RLKs are required for RLPs to activate downstream signaling. The RLPs Cf-4 and Ve1 of tomato (Solanum lycopersicum) mediate resistance to the fungal pathogens Cladosporium fulvum and Verticillium dahliae, respectively. Despite their importance, the mechanism by which these immune receptors mediate downstream signaling upon recognition of their matching ligand, Avr4 and Ave1, remained enigmatic. Here we show that the tomato ortholog of the Arabidopsis thaliana RLK Suppressor Of BIR1-1/Evershed (SOBIR1/EVR) and its close homolog S. lycopersicum (Sl)SOBIR1-like interact in planta with both Cf-4 and Ve1 and are required for the Cf-4- and Ve1-mediated hypersensitive response and immunity. Tomato SOBIR1/EVR interacts with most of the tested RLPs, but not with the RLKs FLS2, SERK1, SERK3a, BAK1, and CLV1. SOBIR1/EVR is required for stability of the Cf-4 and Ve1 receptors, supporting our observation that these RLPs are present in a complex with SOBIR1/EVR in planta. We show that SOBIR1/EVR is essential for RLP-mediated immunity and propose that the protein functions as a regulatory RLK of this type of cell-surface receptors.

  2. Plant Aquaporin AtPIP1;4 Links Apoplastic H2O2 Induction to Disease Immunity Pathways.

    PubMed

    Tian, Shan; Wang, Xiaobing; Li, Ping; Wang, Hao; Ji, Hongtao; Xie, Junyi; Qiu, Qinglei; Shen, Dan; Dong, Hansong

    2016-07-01

    Hydrogen peroxide (H2O2) is a stable component of reactive oxygen species, and its production in plants represents the successful recognition of pathogen infection and pathogen-associated molecular patterns (PAMPs). This production of H2O2 is typically apoplastic but is subsequently associated with intracellular immunity pathways that regulate disease resistance, such as systemic acquired resistance and PAMP-triggered immunity. Here, we elucidate that an Arabidopsis (Arabidopsis thaliana) aquaporin (i.e. the plasma membrane intrinsic protein AtPIP1;4) acts to close the cytological distance between H2O2 production and functional performance. Expression of the AtPIP1;4 gene in plant leaves is inducible by a bacterial pathogen, and the expression accompanies H2O2 accumulation in the cytoplasm. Under de novo expression conditions, AtPIP1;4 is able to mediate the translocation of externally applied H2O2 into the cytoplasm of yeast (Saccharomyces cerevisiae) cells. In plant cells treated with H2O2, AtPIP1;4 functions as an effective facilitator of H2O2 transport across plasma membranes and mediates the translocation of externally applied H2O2 from the apoplast to the cytoplasm. The H2O2-transport role of AtPIP1;4 is essentially required for the cytoplasmic import of apoplastic H2O2 induced by the bacterial pathogen and two typical PAMPs in the absence of induced production of intracellular H2O2 As a consequence, cytoplasmic H2O2 quantities increase substantially while systemic acquired resistance and PAMP-triggered immunity are activated to repress the bacterial pathogenicity. By contrast, loss-of-function mutation at the AtPIP1;4 gene locus not only nullifies the cytoplasmic import of pathogen- and PAMP-induced apoplastic H2O2 but also cancels the subsequent immune responses, suggesting a pivotal role of AtPIP1;4 in apocytoplastic signal transduction in immunity pathways.

  3. Allelic variation in two distinct Pseudomonas syringae flagellin epitopes modulates the strength of plant immune responses but not bacterial motility

    PubMed Central

    Clarke, Christopher R.; Chinchilla, Delphine; Hind, Sarah R.; Taguchi, Fumiko; Miki, Ryuji; Ichinose, Yuki; Martin, Gregory B.; Leman, Scotland; Felix, Georg; Vinatzer, Boris A.

    2013-01-01

    Summary The bacterial flagellin (FliC) epitopes flg22 and flgII-28 are microbe-associated molecular patterns (MAMPs). While flg22 is recognized by many plant species via the pattern recognition receptor FLS2, neither the flgII-28 receptor nor the extent of flgII-28 recognition by different plant families is known.Here we tested the significance of flgII-28 as a MAMP and the importance of allelic diversity in flg22 and flgII-28 in plant–pathogen interactions using purified peptides and a Pseudomonas syringae ΔfliC mutant complemented with different fliC alleles.Plant genotype and allelic diversity in flg22 and flgII-28 were found to significantly affect the plant immune response but not bacterial motility. Recognition of flgII-28 is restricted to a number of Solanaceous species. While the flgII-28 peptide does not trigger any immune response in Arabidopsis, mutations in both flg22 and flgII-28 have FLS2-dependent effects on virulence. However, expression of a tomato allele of FLS2 does not confer to Nicotiana benthamiana the ability to detect flgII-28 and tomato plants silenced for FLS2 are not altered in flgII-28 recognition.Therefore, MAMP diversification is an effective pathogen virulence strategy and flgII-28 appears to be perceived by a yet unidentified receptor in the Solanaceae although it has an FLS2-dependent virulence effect in Arabidopsis. PMID:23865782

  4. Liver Fibrosis and Mechanisms of the Protective Action of Medicinal Plants Targeting Inflammation and the Immune Response

    PubMed Central

    Moreno-Cuevas, Jorge E.; González-Garza, María Teresa; Maldonado-Bernal, Carmen; Cruz-Vega, Delia Elva

    2015-01-01

    Inflammation is a central feature of liver fibrosis as suggested by its role in the activation of hepatic stellate cells leading to extracellular matrix deposition. During liver injury, inflammatory cells are recruited in the injurious site through chemokines attraction. Thus, inflammation could be a target to reduce liver fibrosis. The pandemic trend of obesity, combined with the high incidence of alcohol intake and viral hepatitis infections, highlights the urgent need to find accessible antifibrotic therapies. Medicinal plants are achieving popularity as antifibrotic agents, supported by their safety, cost-effectiveness, and versatility. The aim of this review is to describe the role of inflammation and the immune response in the pathogenesis of liver fibrosis and detail the mechanisms of inhibition of both events by medicinal plants in order to reduce liver fibrosis. PMID:25954568

  5. The pepper phosphoenolpyruvate carboxykinase CaPEPCK1 is involved in plant immunity against bacterial and oomycete pathogens.

    PubMed

    Choi, Du Seok; Kim, Nak Hyun; Hwang, Byung Kook

    2015-09-01

    Phosphoenolpyruvate carboxykinase, a member of the lyase family, is involved in the metabolic pathway of gluconeogenesis in organisms. Although the major function of PEPCK in gluconeogenesis is well established, it is unclear whether this enzyme is involved in plant immunity. Here, we isolated and identified the pepper (Capsicum annuum) PEPCK (CaPEPCK1) gene from pepper leaves infected with Xanthomonas campestris pv. vesicatoria (Xcv). CaPEPCK1 was strongly expressed in pepper leaves during the incompatible interaction with avirulent Xcv and in response to environmental stresses, especially salicylic acid (SA) treatment. PEPCK activity was low in healthy leaves but dramatically increased in avirulent Xcv-infected leaves. Knock-down expression of CaPEPCK1 by virus-induced gene silencing resulted in high levels of susceptibility to both virulent and avirulent Xcv infection. CaPEPCK1 silencing in pepper compromised induction of the basal defense-marker genes CaPR1 (pathogenesis-related 1 protein), CaPR10 (pathogenesis-related 10 protein) and CaDEF1 (defensin) during Xcv infection. SA accumulation was also significantly suppressed in the CaPEPCK1-silenced pepper leaves infected with Xcv. CaPEPCK1 in an Arabidopsis overexpression (OX) line inhibited the proliferation of Pseudomonas syringae pv. tomato (Pst) and Hyaloperonospora arabidopsidis (Hpa). CaPEPCK1-OX plants developed more rapidly, with enlarged leaves, compared to wild-type plants. The T-DNA insertion Arabidopsis orthologous mutants pck1-3 and pck1-4 were more susceptible to the bacterial Pst and oomycete Hpa pathogens than the wild type. Taken together, these results suggest that CaPEPCK positively contributes to plant innate immunity against hemibiotrophic bacterial and obligate biotrophic oomycete pathogens.

  6. Interactions between Verticillium dahliae and its host: vegetative growth, pathogenicity, plant immunity.

    PubMed

    Luo, Xiumei; Xie, Chengjian; Dong, Jinyan; Yang, Xingyong; Sui, Anping

    2014-08-01

    Verticillium dahliae is a soil-borne phytopathogenic fungus that causes vascular wilt diseases in a wide variety of crop plants, resulting in extensive economic losses. In the past 5 years, progress has been made in elaborating the interaction between this hemibiotrophic fungus and its host plants. Some genes responsible for the vegetative growth and/or pathogenicity in V. dahliae have been identified. Plants have accrued a series of defense mechanisms, including inducible defense signaling pathways and some resistant genes to combat V. dahliae infection. Here, we have reviewed the progress in V. dahliae-plant interaction research.

  7. Activation of Plant Innate Immunity by Extracellular High Mobility Group Box 3 and Its Inhibition by Salicylic Acid

    PubMed Central

    Choi, Hyong Woo; Manohar, Murli; Manosalva, Patricia; Tian, Miaoying; Moreau, Magali; Klessig, Daniel F.

    2016-01-01

    Damage-associated molecular pattern molecules (DAMPs) signal the presence of tissue damage to induce immune responses in plants and animals. Here, we report that High Mobility Group Box 3 (HMGB3) is a novel plant DAMP. Extracellular HMGB3, through receptor-like kinases BAK1 and BKK1, induced hallmark innate immune responses, including i) MAPK activation, ii) defense-related gene expression, iii) callose deposition, and iv) enhanced resistance to Botrytis cinerea. Infection by necrotrophic B. cinerea released HMGB3 into the extracellular space (apoplast). Silencing HMGBs enhanced susceptibility to B. cinerea, while HMGB3 injection into apoplast restored resistance. Like its human counterpart, HMGB3 binds salicylic acid (SA), which results in inhibition of its DAMP activity. An SA-binding site mutant of HMGB3 retained its DAMP activity, which was no longer inhibited by SA, consistent with its reduced SA-binding activity. These results provide cross-kingdom evidence that HMGB proteins function as DAMPs and that SA is their conserved inhibitor. PMID:27007252

  8. Arabidopsis SENESCENCE-ASSOCIATED GENE101 stabilizes and signals within an ENHANCED DISEASE SUSCEPTIBILITY1 complex in plant innate immunity.

    PubMed

    Feys, Bart J; Wiermer, Marcel; Bhat, Riyaz A; Moisan, Lisa J; Medina-Escobar, Nieves; Neu, Christina; Cabral, Adriana; Parker, Jane E

    2005-09-01

    Plant innate immunity against invasive biotrophic pathogens depends on the intracellular defense regulator ENHANCED DISEASE SUSCEPTIBILITY1 (EDS1). We show here that Arabidopsis thaliana EDS1 interacts in vivo with another protein, SENESCENCE-ASSOCIATED GENE101 (SAG101), discovered through a proteomic approach to identify new EDS1 pathway components. Together with PHYTOALEXIN-DEFICIENT4 (PAD4), a known EDS1 interactor, SAG101 contributes intrinsic and indispensable signaling activity to EDS1-dependent resistance. The combined activities of SAG101 and PAD4 are necessary for programmed cell death triggered by the Toll-Interleukin-1 Receptor type of nucleotide binding/leucine-rich repeat immune receptor in response to avirulent pathogen isolates and in restricting the growth of normally virulent pathogens. We further demonstrate by a combination of cell fractionation, coimmunoprecipitation, and fluorescence resonance energy transfer experiments the existence of an EDS1-SAG101 complex inside the nucleus that is molecularly and spatially distinct from EDS1-PAD4 associations in the nucleus and cytoplasm. By contrast, EDS1 homomeric interactions were detected in the cytoplasm but not inside the nucleus. These data, combined with evidence for coregulation between individual EDS1 complexes, suggest that dynamic interactions of EDS1 and its signaling partners in multiple cell compartments are important for plant defense signal relay.

  9. Asynchrony between Host Plant and Insects-Defoliator within a Tritrophic System: The Role of Herbivore Innate Immunity

    PubMed Central

    Martemyanov, Vyacheslav V.; Pavlushin, Sergey V.; Dubovskiy, Ivan M.; Yushkova, Yuliya V.; Morosov, Sergey V.; Chernyak, Elena I.; Efimov, Vadim M.; Ruuhola, Teija; Glupov, Victor V.

    2015-01-01

    The effects of asynchrony in the phenology of spring-feeding insect-defoliators and their host plants on insects’ fitness, as well as the importance of this effect for the population dynamics of outbreaking species of insects, is a widespread and well-documented phenomenon. However, the spreading of this phenomenon through the food chain, and especially those mechanisms operating this spreading, are still unclear. In this paper, we study the effect of seasonally declined leafquality (estimated in terms of phenolics and nitrogen content) on herbivore fitness, immune parameters and resistance against pathogen by using the silver birch Betula pendula—gypsy moth Lymantria dispar—nucleopolyhedrovirus as the tritrophic system. We show that a phenological mismatch induced by the delay in the emergence of gypsy moth larvae and following feeding on mature leaves has negative effects on the female pupal weight, on the rate of larval development and on the activity of phenoloxidase in the plasma of haemolymph. In addition, the larval susceptibility to exogenous nucleopolyhydrovirus infection as well as covert virus activation were both enhanced due to the phenological mismatch. The observed effects of phenological mismatch on insect-baculovirus interaction may partially explain the strong and fast fluctuations in the population dynamics of the gypsy moth that is often observed in the studied part of the defoliator area. This study also reveals some indirect mechanisms of effect related to host plant quality, which operate through the insect innate immune status and affect resistance to both exogenous and endogenous virus. PMID:26115118

  10. Asynchrony between Host Plant and Insects-Defoliator within a Tritrophic System: The Role of Herbivore Innate Immunity.

    PubMed

    Martemyanov, Vyacheslav V; Pavlushin, Sergey V; Dubovskiy, Ivan M; Yushkova, Yuliya V; Morosov, Sergey V; Chernyak, Elena I; Efimov, Vadim M; Ruuhola, Teija; Glupov, Victor V

    2015-01-01

    The effects of asynchrony in the phenology of spring-feeding insect-defoliators and their host plants on insects' fitness, as well as the importance of this effect for the population dynamics of outbreaking species of insects, is a widespread and well-documented phenomenon. However, the spreading of this phenomenon through the food chain, and especially those mechanisms operating this spreading, are still unclear. In this paper, we study the effect of seasonally declined leafquality (estimated in terms of phenolics and nitrogen content) on herbivore fitness, immune parameters and resistance against pathogen by using the silver birch Betula pendula--gypsy moth Lymantria dispar--nucleopolyhedrovirus as the tritrophic system. We show that a phenological mismatch induced by the delay in the emergence of gypsy moth larvae and following feeding on mature leaves has negative effects on the female pupal weight, on the rate of larval development and on the activity of phenoloxidase in the plasma of haemolymph. In addition, the larval susceptibility to exogenous nucleopolyhydrovirus infection as well as covert virus activation were both enhanced due to the phenological mismatch. The observed effects of phenological mismatch on insect-baculovirus interaction may partially explain the strong and fast fluctuations in the population dynamics of the gypsy moth that is often observed in the studied part of the defoliator area. This study also reveals some indirect mechanisms of effect related to host plant quality, which operate through the insect innate immune status and affect resistance to both exogenous and endogenous virus. PMID:26115118

  11. Asynchrony between Host Plant and Insects-Defoliator within a Tritrophic System: The Role of Herbivore Innate Immunity.

    PubMed

    Martemyanov, Vyacheslav V; Pavlushin, Sergey V; Dubovskiy, Ivan M; Yushkova, Yuliya V; Morosov, Sergey V; Chernyak, Elena I; Efimov, Vadim M; Ruuhola, Teija; Glupov, Victor V

    2015-01-01

    The effects of asynchrony in the phenology of spring-feeding insect-defoliators and their host plants on insects' fitness, as well as the importance of this effect for the population dynamics of outbreaking species of insects, is a widespread and well-documented phenomenon. However, the spreading of this phenomenon through the food chain, and especially those mechanisms operating this spreading, are still unclear. In this paper, we study the effect of seasonally declined leafquality (estimated in terms of phenolics and nitrogen content) on herbivore fitness, immune parameters and resistance against pathogen by using the silver birch Betula pendula--gypsy moth Lymantria dispar--nucleopolyhedrovirus as the tritrophic system. We show that a phenological mismatch induced by the delay in the emergence of gypsy moth larvae and following feeding on mature leaves has negative effects on the female pupal weight, on the rate of larval development and on the activity of phenoloxidase in the plasma of haemolymph. In addition, the larval susceptibility to exogenous nucleopolyhydrovirus infection as well as covert virus activation were both enhanced due to the phenological mismatch. The observed effects of phenological mismatch on insect-baculovirus interaction may partially explain the strong and fast fluctuations in the population dynamics of the gypsy moth that is often observed in the studied part of the defoliator area. This study also reveals some indirect mechanisms of effect related to host plant quality, which operate through the insect innate immune status and affect resistance to both exogenous and endogenous virus.

  12. Activation of Plant Innate Immunity by Extracellular High Mobility Group Box 3 and Its Inhibition by Salicylic Acid.

    PubMed

    Choi, Hyong Woo; Manohar, Murli; Manosalva, Patricia; Tian, Miaoying; Moreau, Magali; Klessig, Daniel F

    2016-03-01

    Damage-associated molecular pattern molecules (DAMPs) signal the presence of tissue damage to induce immune responses in plants and animals. Here, we report that High Mobility Group Box 3 (HMGB3) is a novel plant DAMP. Extracellular HMGB3, through receptor-like kinases BAK1 and BKK1, induced hallmark innate immune responses, including i) MAPK activation, ii) defense-related gene expression, iii) callose deposition, and iv) enhanced resistance to Botrytis cinerea. Infection by necrotrophic B. cinerea released HMGB3 into the extracellular space (apoplast). Silencing HMGBs enhanced susceptibility to B. cinerea, while HMGB3 injection into apoplast restored resistance. Like its human counterpart, HMGB3 binds salicylic acid (SA), which results in inhibition of its DAMP activity. An SA-binding site mutant of HMGB3 retained its DAMP activity, which was no longer inhibited by SA, consistent with its reduced SA-binding activity. These results provide cross-kingdom evidence that HMGB proteins function as DAMPs and that SA is their conserved inhibitor.

  13. NLR-Associating Transcription Factor bHLH84 and Its Paralogs Function Redundantly in Plant Immunity

    PubMed Central

    Xu, Fang; Kapos, Paul; Cheng, Yu Ti; Li, Meng; Zhang, Yuelin; Li, Xin

    2014-01-01

    In plants and animals, nucleotide-binding and leucine-rich repeat domain containing (NLR) immune receptors are utilized to detect the presence or activities of pathogen-derived molecules. However, the mechanisms by which NLR proteins induce defense responses remain unclear. Here, we report the characterization of one basic Helix-loop-Helix (bHLH) type transcription factor (TF), bHLH84, identified from a reverse genetic screen. It functions as a transcriptional activator that enhances the autoimmunity of NLR mutant snc1 (suppressor of npr1-1, constitutive 1) and confers enhanced immunity in wild-type backgrounds when overexpressed. Simultaneously knocking out three closely related bHLH paralogs attenuates RPS4-mediated immunity and partially suppresses the autoimmune phenotypes of snc1, while overexpression of the other two close paralogs also renders strong autoimmunity, suggesting functional redundancy in the gene family. Intriguingly, the autoimmunity conferred by bHLH84 overexpression can be largely suppressed by the loss-of-function snc1-r1 mutation, suggesting that SNC1 is required for its proper function. In planta co-immunoprecipitation revealed interactions between not only bHLH84 and SNC1, but also bHLH84 and RPS4, indicating that bHLH84 associates with these NLRs. Together with previous finding that SNC1 associates with repressor TPR1 to repress negative regulators, we hypothesize that nuclear NLR proteins may interact with both transcriptional repressors and activators during immune responses, enabling potentially faster and more robust transcriptional reprogramming upon pathogen recognition. PMID:25144198

  14. Innate immune response, intestinal morphology and microbiota changes in Senegalese sole fed plant protein diets with probiotics or autolysed yeast.

    PubMed

    Batista, S; Medina, A; Pires, M A; Moriñigo, M A; Sansuwan, K; Fernandes, J M O; Valente, L M P; Ozório, R O A

    2016-08-01

    The effects of using plant ingredients in Senegalese sole (Solea senegalensis) diet on immune competence and intestine morphology and microbial ecology are still controversial. Probiotics or immunostimulants can potentially alter the intestinal microbiota in a way that protects fish against pathogens. The current study aimed to examine the intestine histology and microbiota and humoral innate immune response in juvenile sole fed diets with low (35 %) or high (72 %) content of plant protein (PP) ingredients supplemented with a multispecies probiotic bacteria or autolysed yeast. Fish fed the probiotic diet had lower growth performance. Lysozyme and complement activities were significantly higher in fish fed PP72 diets than in their counterparts fed PP35 diets after 17 and 38 days of feeding. At 2 days of feeding, fish fed unsupplemented PP72 showed larger intestine section area and longer villus than fish fed unsupplemented PP35. At 17 days of feeding, fish fed unsupplemented PP72 showed more goblet cells than the other dietary groups, except the group fed yeast supplemented PP35 diet. High dietary PP level, acutely stimulate fish innate immune defence of the fish after 2 and 17 days of feeding. However, this effect does not occur after 73 days of feeding, suggesting a habituation to dietary treatments and/or immunosuppression, with a reduction in the number of the goblet cells. Fish fed for 38 days with diets supplemented with autolysed yeast showed longer intestinal villus. The predominant bacteria found in sole intestine were Vibrio sp. and dietary probiotic supplementation caused a reduction in Vibrio content, regardless of the PP level.

  15. Innate immune response, intestinal morphology and microbiota changes in Senegalese sole fed plant protein diets with probiotics or autolysed yeast.

    PubMed

    Batista, S; Medina, A; Pires, M A; Moriñigo, M A; Sansuwan, K; Fernandes, J M O; Valente, L M P; Ozório, R O A

    2016-08-01

    The effects of using plant ingredients in Senegalese sole (Solea senegalensis) diet on immune competence and intestine morphology and microbial ecology are still controversial. Probiotics or immunostimulants can potentially alter the intestinal microbiota in a way that protects fish against pathogens. The current study aimed to examine the intestine histology and microbiota and humoral innate immune response in juvenile sole fed diets with low (35 %) or high (72 %) content of plant protein (PP) ingredients supplemented with a multispecies probiotic bacteria or autolysed yeast. Fish fed the probiotic diet had lower growth performance. Lysozyme and complement activities were significantly higher in fish fed PP72 diets than in their counterparts fed PP35 diets after 17 and 38 days of feeding. At 2 days of feeding, fish fed unsupplemented PP72 showed larger intestine section area and longer villus than fish fed unsupplemented PP35. At 17 days of feeding, fish fed unsupplemented PP72 showed more goblet cells than the other dietary groups, except the group fed yeast supplemented PP35 diet. High dietary PP level, acutely stimulate fish innate immune defence of the fish after 2 and 17 days of feeding. However, this effect does not occur after 73 days of feeding, suggesting a habituation to dietary treatments and/or immunosuppression, with a reduction in the number of the goblet cells. Fish fed for 38 days with diets supplemented with autolysed yeast showed longer intestinal villus. The predominant bacteria found in sole intestine were Vibrio sp. and dietary probiotic supplementation caused a reduction in Vibrio content, regardless of the PP level. PMID:27183997

  16. Photosystem II Repair and Plant Immunity: Lessons Learned from Arabidopsis Mutant Lacking the THYLAKOID LUMEN PROTEIN 18.3.

    PubMed

    Järvi, Sari; Isojärvi, Janne; Kangasjärvi, Saijaliisa; Salojärvi, Jarkko; Mamedov, Fikret; Suorsa, Marjaana; Aro, Eva-Mari

    2016-01-01

    Chloroplasts play an important role in the cellular sensing of abiotic and biotic stress. Signals originating from photosynthetic light reactions, in the form of redox and pH changes, accumulation of reactive oxygen and electrophile species or stromal metabolites are of key importance in chloroplast retrograde signaling. These signals initiate plant acclimation responses to both abiotic and biotic stresses. To reveal the molecular responses activated by rapid fluctuations in growth light intensity, gene expression analysis was performed with Arabidopsis thaliana wild type and the tlp18.3 mutant plants, the latter showing a stunted growth phenotype under fluctuating light conditions (Biochem. J, 406, 415-425). Expression pattern of genes encoding components of the photosynthetic electron transfer chain did not differ between fluctuating and constant light conditions, neither in wild type nor in tlp18.3 plants, and the composition of the thylakoid membrane protein complexes likewise remained unchanged. Nevertheless, the fluctuating light conditions repressed in wild-type plants a broad spectrum of genes involved in immune responses, which likely resulted from shade-avoidance responses and their intermixing with hormonal signaling. On the contrary, in the tlp18.3 mutant plants there was an imperfect repression of defense-related transcripts upon growth under fluctuating light, possibly by signals originating from minor malfunction of the photosystem II (PSII) repair cycle, which directly or indirectly modulated the transcript abundances of genes related to light perception via phytochromes. Consequently, a strong allocation of resources to defense reactions in the tlp18.3 mutant plants presumably results in the stunted growth phenotype under fluctuating light.

  17. Photosystem II Repair and Plant Immunity: Lessons Learned from Arabidopsis Mutant Lacking the THYLAKOID LUMEN PROTEIN 18.3

    PubMed Central

    Järvi, Sari; Isojärvi, Janne; Kangasjärvi, Saijaliisa; Salojärvi, Jarkko; Mamedov, Fikret; Suorsa, Marjaana; Aro, Eva-Mari

    2016-01-01

    Chloroplasts play an important role in the cellular sensing of abiotic and biotic stress. Signals originating from photosynthetic light reactions, in the form of redox and pH changes, accumulation of reactive oxygen and electrophile species or stromal metabolites are of key importance in chloroplast retrograde signaling. These signals initiate plant acclimation responses to both abiotic and biotic stresses. To reveal the molecular responses activated by rapid fluctuations in growth light intensity, gene expression analysis was performed with Arabidopsis thaliana wild type and the tlp18.3 mutant plants, the latter showing a stunted growth phenotype under fluctuating light conditions (Biochem. J, 406, 415–425). Expression pattern of genes encoding components of the photosynthetic electron transfer chain did not differ between fluctuating and constant light conditions, neither in wild type nor in tlp18.3 plants, and the composition of the thylakoid membrane protein complexes likewise remained unchanged. Nevertheless, the fluctuating light conditions repressed in wild-type plants a broad spectrum of genes involved in immune responses, which likely resulted from shade-avoidance responses and their intermixing with hormonal signaling. On the contrary, in the tlp18.3 mutant plants there was an imperfect repression of defense-related transcripts upon growth under fluctuating light, possibly by signals originating from minor malfunction of the photosystem II (PSII) repair cycle, which directly or indirectly modulated the transcript abundances of genes related to light perception via phytochromes. Consequently, a strong allocation of resources to defense reactions in the tlp18.3 mutant plants presumably results in the stunted growth phenotype under fluctuating light. PMID:27064270

  18. Bacterial cyclic beta-(1,2)-glucan acts in systemic suppression of plant immune responses.

    PubMed

    Rigano, Luciano Ariel; Payette, Caroline; Brouillard, Geneviève; Marano, Maria Rosa; Abramowicz, Laura; Torres, Pablo Sebastián; Yun, Maximina; Castagnaro, Atilio Pedro; Oirdi, Mohamed El; Dufour, Vanessa; Malamud, Florencia; Dow, John Maxwell; Bouarab, Kamal; Vojnov, Adrian Alberto

    2007-06-01

    Although cyclic glucans have been shown to be important for a number of symbiotic and pathogenic bacterium-plant interactions, their precise roles are unclear. Here, we examined the role of cyclic beta-(1,2)-glucan in the virulence of the black rot pathogen Xanthomonas campestris pv campestris (Xcc). Disruption of the Xcc nodule development B (ndvB) gene, which encodes a glycosyltransferase required for cyclic glucan synthesis, generated a mutant that failed to synthesize extracellular cyclic beta-(1,2)-glucan and was compromised in virulence in the model plants Arabidopsis thaliana and Nicotiana benthamiana. Infection of the mutant bacterium in N. benthamiana was associated with enhanced callose deposition and earlier expression of the PATHOGENESIS-RELATED1 (PR-1) gene. Application of purified cyclic beta-(1,2)-glucan prior to inoculation of the ndvB mutant suppressed the accumulation of callose deposition and the expression of PR-1 in N. benthamiana and restored virulence in both N. benthamiana and Arabidopsis plants. These effects were seen when cyclic glucan and bacteria were applied either to the same or to different leaves. Cyclic beta-(1,2)-glucan-induced systemic suppression was associated with the transport of the molecule throughout the plant. Systemic suppression is a novel counterdefensive strategy that may facilitate pathogen spread in plants and may have important implications for the understanding of plant-pathogen coevolution and for the development of phytoprotection measures. PMID:17601826

  19. The plant immunity inducer pipecolic acid accumulates in the xylem sap and leaves of soybean seedlings following Fusarium virguliforme infection.

    PubMed

    Abeysekara, Nilwala S; Swaminathan, Sivakumar; Desai, Nalini; Guo, Lining; Bhattacharyya, Madan K

    2016-02-01

    The causal agent of the soybean sudden death syndrome (SDS), Fusarium virguliforme, remains in infected roots and secretes toxins to cause foliar SDS. In this study we investigated the xylem sap, roots, and leaves of F. virguliforme-infected and -uninfected soybean seedlings for any changes in a set of over 3,000 metabolites following pathogen infection by conducting GC/MS and LC/MS/MS, and detected 273 biochemicals. Levels of many intermediates of the TCA cycle were reduced suggesting suppression of this metabolic pathway by the pathogen. There was an increased accumulation of peroxidated lipids in leaves of F. virguliforme-infected plants suggesting possible involvement of free radicals and lipoxygenases in foliar SDS development. Levels of both isoflavone conjugates and isoflavonoid phytoalexins were decreased in infected roots suggesting degradation of these metabolites by the pathogen to promote root necrosis. The levels of the plant immunity inducer pipecolic acid (Pip) and the plant hormone salicylic acid (SA) were significantly increased in xylem sap (in case of Pip) and leaves (in case of both Pip and SA) of F. virguliforme-infected soybean plants compared to the control plants. This suggests a major signaling role of Pip in inducing host defense responses in above ground parts of the F. virguliforme-infected soybean. Increased accumulation of pipecolic acid in foliar tissues was associated with the induction of GmALD1, the soybean homolog of Arabidopsis ALD1. This metabolomics study generated several novel hypotheses for studying the mechanisms of SDS development in soybean.

  20. A Phytophthora sojae effector suppresses endoplasmic reticulum stress-mediated immunity by stabilizing plant Binding immunoglobulin Proteins

    PubMed Central

    Jing, Maofeng; Guo, Baodian; Li, Haiyang; Yang, Bo; Wang, Haonan; Kong, Guanghui; Zhao, Yao; Xu, Huawei; Wang, Yan; Ye, Wenwu; Dong, Suomeng; Qiao, Yongli; Tyler, Brett M.; Ma, Wenbo; Wang, Yuanchao

    2016-01-01

    Phytophthora pathogens secrete an array of specific effector proteins to manipulate host innate immunity to promote pathogen colonization. However, little is known about the host targets of effectors and the specific mechanisms by which effectors increase susceptibility. Here we report that the soybean pathogen Phytophthora sojae uses an essential effector PsAvh262 to stabilize endoplasmic reticulum (ER)-luminal binding immunoglobulin proteins (BiPs), which act as negative regulators of plant resistance to Phytophthora. By stabilizing BiPs, PsAvh262 suppresses ER stress-triggered cell death and facilitates Phytophthora infection. The direct targeting of ER stress regulators may represent a common mechanism of host manipulation by microbes. PMID:27256489

  1. Korean traditional natural herbs and plants as immune enhancing, antidiabetic, chemopreventive, and antioxidative agents: a narrative review and perspective.

    PubMed

    Park, Hyunjin; Kim, Hyun-Sook

    2014-01-01

    The world is becoming increasingly interested in Korean food and its ingredients. The attention goes beyond the typical examples, such as kimchi and fermented sauces; peculiar food ingredients that are widely consumed in Korea are now entering the world's functional food markets. This trend was supported by scientific research, and this review seeks to combine and summarize the findings of the past 10 years. The results are organized into four groups depending on whether the ingredient strengthens the immune system, has antidiabetic effects, has chemopreventive effects, or has an antioxidative effects. We would also like to point out that this review only covers the topic of Korean traditional plants and herbs. After the summary of research findings, we discuss challenges and opportunities, exploring the direction of future research and the potential of Korean traditional food ingredients in food industry and markets.

  2. Gaseous 3-pentanol primes plant immunity against a bacterial speck pathogen, Pseudomonas syringae pv. tomato via salicylic acid and jasmonic acid-dependent signaling pathways in Arabidopsis

    PubMed Central

    Song, Geun C.; Choi, Hye K.; Ryu, Choong-Min

    2015-01-01

    3-Pentanol is an active organic compound produced by plants and is a component of emitted insect sex pheromones. A previous study reported that drench application of 3-pentanol elicited plant immunity against microbial pathogens and an insect pest in crop plants. Here, we evaluated whether 3-pentanol and the derivatives 1-pentanol and 2-pentanol induced plant systemic resistance using the in vitro I-plate system. Exposure of Arabidopsis seedlings to 10 μM and 100 nM 3-pentanol evaporate elicited an immune response to Pseudomonas syringae pv. tomato DC3000. We performed quantitative real-time PCR to investigate the 3-pentanol-mediated Arabidopsis immune responses by determining Pathogenesis-Related (PR) gene expression levels associated with defense signaling through salicylic acid (SA), jasmonic acid (JA), and ethylene signaling pathways. The results show that exposure to 3-pentanol and subsequent pathogen challenge upregulated PDF1.2 and PR1 expression. Selected Arabidopsis mutants confirmed that the 3-pentanol-mediated immune response involved SA and JA signaling pathways and the NPR1 gene. Taken together, this study indicates that gaseous 3-pentanol triggers induced resistance in Arabidopsis by priming SA and JA signaling pathways. To our knowledge, this is the first report that a volatile compound of an insect sex pheromone triggers plant systemic resistance against a bacterial pathogen. PMID:26500665

  3. Apoplastic venom allergen-like proteins of cyst nematodes modulate the activation of basal plant innate immunity by cell surface receptors.

    PubMed

    Lozano-Torres, Jose L; Wilbers, Ruud H P; Warmerdam, Sonja; Finkers-Tomczak, Anna; Diaz-Granados, Amalia; van Schaik, Casper C; Helder, Johannes; Bakker, Jaap; Goverse, Aska; Schots, Arjen; Smant, Geert

    2014-12-01

    Despite causing considerable damage to host tissue during the onset of parasitism, nematodes establish remarkably persistent infections in both animals and plants. It is thought that an elaborate repertoire of effector proteins in nematode secretions suppresses damage-triggered immune responses of the host. However, the nature and mode of action of most immunomodulatory compounds in nematode secretions are not well understood. Here, we show that venom allergen-like proteins of plant-parasitic nematodes selectively suppress host immunity mediated by surface-localized immune receptors. Venom allergen-like proteins are uniquely conserved in secretions of all animal- and plant-parasitic nematodes studied to date, but their role during the onset of parasitism has thus far remained elusive. Knocking-down the expression of the venom allergen-like protein Gr-VAP1 severely hampered the infectivity of the potato cyst nematode Globodera rostochiensis. By contrast, heterologous expression of Gr-VAP1 and two other venom allergen-like proteins from the beet cyst nematode Heterodera schachtii in plants resulted in the loss of basal immunity to multiple unrelated pathogens. The modulation of basal immunity by ectopic venom allergen-like proteins in Arabidopsis thaliana involved extracellular protease-based host defenses and non-photochemical quenching in chloroplasts. Non-photochemical quenching regulates the initiation of the defense-related programmed cell death, the onset of which was commonly suppressed by venom allergen-like proteins from G. rostochiensis, H. schachtii, and the root-knot nematode Meloidogyne incognita. Surprisingly, these venom allergen-like proteins only affected the programmed cell death mediated by surface-localized immune receptors. Furthermore, the delivery of venom allergen-like proteins into host tissue coincides with the enzymatic breakdown of plant cell walls by migratory nematodes. We, therefore, conclude that parasitic nematodes most likely utilize

  4. Apoplastic Venom Allergen-like Proteins of Cyst Nematodes Modulate the Activation of Basal Plant Innate Immunity by Cell Surface Receptors

    PubMed Central

    Lozano-Torres, Jose L.; Wilbers, Ruud H. P.; Warmerdam, Sonja; Finkers-Tomczak, Anna; Diaz-Granados, Amalia; van Schaik, Casper C.; Helder, Johannes; Bakker, Jaap; Goverse, Aska; Schots, Arjen; Smant, Geert

    2014-01-01

    Despite causing considerable damage to host tissue during the onset of parasitism, nematodes establish remarkably persistent infections in both animals and plants. It is thought that an elaborate repertoire of effector proteins in nematode secretions suppresses damage-triggered immune responses of the host. However, the nature and mode of action of most immunomodulatory compounds in nematode secretions are not well understood. Here, we show that venom allergen-like proteins of plant-parasitic nematodes selectively suppress host immunity mediated by surface-localized immune receptors. Venom allergen-like proteins are uniquely conserved in secretions of all animal- and plant-parasitic nematodes studied to date, but their role during the onset of parasitism has thus far remained elusive. Knocking-down the expression of the venom allergen-like protein Gr-VAP1 severely hampered the infectivity of the potato cyst nematode Globodera rostochiensis. By contrast, heterologous expression of Gr-VAP1 and two other venom allergen-like proteins from the beet cyst nematode Heterodera schachtii in plants resulted in the loss of basal immunity to multiple unrelated pathogens. The modulation of basal immunity by ectopic venom allergen-like proteins in Arabidopsis thaliana involved extracellular protease-based host defenses and non-photochemical quenching in chloroplasts. Non-photochemical quenching regulates the initiation of the defense-related programmed cell death, the onset of which was commonly suppressed by venom allergen-like proteins from G. rostochiensis, H. schachtii, and the root-knot nematode Meloidogyne incognita. Surprisingly, these venom allergen-like proteins only affected the programmed cell death mediated by surface-localized immune receptors. Furthermore, the delivery of venom allergen-like proteins into host tissue coincides with the enzymatic breakdown of plant cell walls by migratory nematodes. We, therefore, conclude that parasitic nematodes most likely utilize

  5. Plasmodesmata localizing proteins regulate transport and signaling during systemic acquired immunity in plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Systemic acquired resistance (SAR) in plants is mediated by the signaling molecules azelaic acid (AzA),glycerol-3-phosphate (G3P), and salicylic acid (SA).Here, we show that AzA and G3P transport occurs via the symplastic route, which is regulated by channels known as plasmodesmata (PD). In contrast...

  6. Homologous RXLR effectors from Hyaloperonospora arabidopsidis and Phytophthora sojae suppress immunity in distantly related plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Diverse pathogens secrete effector proteins into plant cells to manipulate host cellular processes. Oomycete pathogens contain very large complements of predicted effector genes defined by an RXLR host cell entry motif. The genome of Hyaloperonospora arabidopsidis (Hpa, downy mildew of Arabidopsis) ...

  7. [Effect of plant polysaccharides on TH1-dependent immune response: screening investigation].

    PubMed

    Danilets, M G; Bel'skiĭ, Iu P; Gur'ev, A M; Belousov, M V; Bel'skaia, N V; Trofimova, E S; Uchasova, E G; Alhmedzhanov, R R; Ligacheva, A A; Iusbov, M S; Agefonov, V I

    2010-06-01

    We have studied the influence of water-soluble polysaccharides isolated from Tussilago farfara L. leaves, Betula verrucosa Ehrh. leaves, Calendula officinalis L. flowers, Acorus calamus rhizomes, Inula helenium L. rhizomes, overground part of Trifolium pretense L., and overground part ofArtemisia absinthium L., on Thl immune response induced by sheep red blood cells and on NO production by murine peritoneal macrophages in vitro. All the investigated polysaccharides have stimulated a Th1 response. Polysaccharides isolated from Betula verrucosa leaves did not influence NO synthesis, while polysaccharides of Tussilago farfara leaves and Acorus calamus rhizomes stimulated NO synthase of murine macrophages on a level comparable with that of lipopolysaccharides (LPS). Polysaccharides from Inula helenium rhizomes, Calendula officinalis flowers, and overground parts of Trifolium pretense and Artemisia absinthium also stimulated NO production, but to a lower extent in comparison to LPS. PMID:20726346

  8. Analysis of Globodera rostochiensis effectors reveals conserved functions of SPRYSEC proteins in suppressing and eliciting plant immune responses

    PubMed Central

    Ali, Shawkat; Magne, Maxime; Chen, Shiyan; Obradovic, Natasa; Jamshaid, Lubna; Wang, Xiaohong; Bélair, Guy; Moffett, Peter

    2015-01-01

    Potato cyst nematodes (PCNs), including Globodera rostochiensis (Woll.), are important pests of potato. Plant parasitic nematodes produce multiple effector proteins, secreted from their stylets, to successfully infect their hosts. These include proteins delivered to the apoplast and to the host cytoplasm. A number of effectors from G. rostochiensis predicted to be delivered to the host cytoplasm have been identified, including several belonging to the secreted SPRY domain (SPRYSEC) family. SPRYSEC proteins are unique to members of the genus Globodera and have been implicated in both the induction and the repression of host defense responses. We have tested the properties of six different G. rostochiensis SPRYSEC proteins by expressing them in Nicotiana benthamiana and N. tabacum. We have found that all SPRYSEC proteins tested are able to suppress defense responses induced by NB-LRR proteins as well as cell death induced by elicitors, suggesting that defense repression is a common characteristic of members of this effector protein family. At the same time, GrSPRYSEC-15 elicited a defense responses in N. tabacum, which was found to be resistant to a virus expressing GrSPRYSEC-15. These results suggest that SPRYSEC proteins may possess characteristics that allow them to be recognized by the plant immune system. PMID:26322064

  9. Phosphorylation-Coupled Proteolysis of the Transcription Factor MYC2 Is Important for Jasmonate-Signaled Plant Immunity

    PubMed Central

    Zhai, Qingzhe; Yan, Liuhua; Tan, Dan; Chen, Rong; Sun, Jiaqiang; Gao, Liyan; Dong, Meng-Qiu; Wang, Yingchun; Li, Chuanyou

    2013-01-01

    As a master regulator of jasmonic acid (JA)–signaled plant immune responses, the basic helix-loop-helix (bHLH) Leu zipper transcription factor MYC2 differentially regulates different subsets of JA–responsive genes through distinct mechanisms. However, how MYC2 itself is regulated at the protein level remains unknown. Here, we show that proteolysis of MYC2 plays a positive role in regulating the transcription of its target genes. We discovered a 12-amino-acid element in the transcription activation domain (TAD) of MYC2 that is required for both the proteolysis and the transcriptional activity of MYC2. Interestingly, MYC2 phosphorylation at residue Thr328, which facilitates its turnover, is also required for the MYC2 function to regulate gene transcription. Together, these results reveal that phosphorylation-coupled turnover of MYC2 stimulates its transcription activity. Our results exemplify that, as with animals, plants employ an “activation by destruction” mechanism to fine-tune their transcriptome to adapt to their ever-changing environment. PMID:23593022

  10. Structural basis for signaling by exclusive EDS1 heteromeric complexes with SAG101 or PAD4 in plant innate immunity.

    PubMed

    Wagner, Stephan; Stuttmann, Johannes; Rietz, Steffen; Guerois, Raphael; Brunstein, Elena; Bautor, Jaqueline; Niefind, Karsten; Parker, Jane E

    2013-12-11

    Biotrophic plant pathogens encounter a postinfection basal resistance layer controlled by the lipase-like protein enhanced disease susceptibility 1 (EDS1) and its sequence-related interaction partners, senescence-associated gene 101 (SAG101) and phytoalexin deficient 4 (PAD4). Maintainance of separate EDS1 family member clades through angiosperm evolution suggests distinct functional attributes. We report the Arabidopsis EDS1-SAG101 heterodimer crystal structure with juxtaposed N-terminal α/β hydrolase and C-terminal α-helical EP domains aligned via a large conserved interface. Mutational analysis of the EDS1-SAG101 heterodimer and a derived EDS1-PAD4 structural model shows that EDS1 signals within mutually exclusive heterocomplexes. Although there is evolutionary conservation of α/β hydrolase topology in all three proteins, a noncatalytic resistance mechanism is indicated. Instead, the respective N-terminal domains appear to facilitate binding of the essential EP domains to create novel interaction surfaces on the heterodimer. Transitions between distinct functional EDS1 heterodimers might explain the central importance and versatility of this regulatory node in plant immunity.

  11. Analysis of Globodera rostochiensis effectors reveals conserved functions of SPRYSEC proteins in suppressing and eliciting plant immune responses.

    PubMed

    Ali, Shawkat; Magne, Maxime; Chen, Shiyan; Obradovic, Natasa; Jamshaid, Lubna; Wang, Xiaohong; Bélair, Guy; Moffett, Peter

    2015-01-01

    Potato cyst nematodes (PCNs), including Globodera rostochiensis (Woll.), are important pests of potato. Plant parasitic nematodes produce multiple effector proteins, secreted from their stylets, to successfully infect their hosts. These include proteins delivered to the apoplast and to the host cytoplasm. A number of effectors from G. rostochiensis predicted to be delivered to the host cytoplasm have been identified, including several belonging to the secreted SPRY domain (SPRYSEC) family. SPRYSEC proteins are unique to members of the genus Globodera and have been implicated in both the induction and the repression of host defense responses. We have tested the properties of six different G. rostochiensis SPRYSEC proteins by expressing them in Nicotiana benthamiana and N. tabacum. We have found that all SPRYSEC proteins tested are able to suppress defense responses induced by NB-LRR proteins as well as cell death induced by elicitors, suggesting that defense repression is a common characteristic of members of this effector protein family. At the same time, GrSPRYSEC-15 elicited a defense responses in N. tabacum, which was found to be resistant to a virus expressing GrSPRYSEC-15. These results suggest that SPRYSEC proteins may possess characteristics that allow them to be recognized by the plant immune system.

  12. Stability of plant immune-receptor resistance proteins is controlled by SKP1-CULLIN1-F-box (SCF)-mediated protein degradation

    PubMed Central

    Cheng, Yu Ti; Li, Yingzhong; Huang, Shuai; Huang, Yan; Dong, Xinnian; Zhang, Yuelin; Li, Xin

    2011-01-01

    The nucleotide-binding domain and leucine-rich repeats containing proteins (NLRs) serve as immune receptors in both plants and animals. Overaccumulation of NLRs often leads to autoimmune responses, suggesting that the levels of these immune receptors must be tightly controlled. However, the mechanism by which NLR protein levels are regulated is unknown. Here we report that the F-box protein CPR1 controls the stability of plant NLR resistance proteins. Loss-of-function mutations in CPR1 lead to higher accumulation of the NLR proteins SNC1 and RPS2, as well as autoactivation of immune responses. The autoimmune responses in cpr1 mutant plants can be largely suppressed by knocking out SNC1. Furthermore, CPR1 interacts with SNC1 and RPS2 in vivo, and overexpressing CPR1 results in reduced accumulation of SNC1 and RPS2, as well as suppression of immunity mediated by these two NLR proteins. Our data suggest that SKP1-CULLIN1-F-box (SCF) complex-mediated stability control of plant NLR proteins plays an important role in regulating their protein levels and preventing autoimmunity. PMID:21873230

  13. Immune response

    MedlinePlus

    Innate immunity; Humoral immunity; Cellular immunity; Immunity; Inflammatory response; Acquired (adaptive) immunity ... and usually does not react against them. INNATE IMMUNITY Innate, or nonspecific, immunity is the defense system ...

  14. Plasmodesmata Localizing Proteins Regulate Transport and Signaling during Systemic Acquired Immunity in Plants.

    PubMed

    Lim, Gah-Hyun; Shine, M B; de Lorenzo, Laura; Yu, Keshun; Cui, Weier; Navarre, Duroy; Hunt, Arthur G; Lee, Jung-Youn; Kachroo, Aardra; Kachroo, Pradeep

    2016-04-13

    Systemic acquired resistance (SAR) in plants is mediated by the signaling molecules azelaic acid (AzA), glycerol-3-phosphate (G3P), and salicylic acid (SA). Here, we show that AzA and G3P transport occurs via the symplastic route, which is regulated by channels known as plasmodesmata (PD). In contrast, SA moves via the extracytosolic apoplast compartment. We found that PD localizing proteins (PDLP) 1 and 5 were required for SAR even though PD permeability in pdlp1 and 5 mutants was comparable to or higher than wild-type plants, respectively. Furthermore, PDLP function was required in the recipient cell, suggesting regulatory function in SAR. Interestingly, overexpression of PDLP5 drastically reduced PD permeability, yet also impaired SAR. PDLP1 interacted with AZI1 (lipid transfer-like protein required for AzA- and G3P-induced SAR) and contributed to its intracellular partitioning. Together, these results reveal the transport routes of SAR chemical signals and highlight the regulatory role of PD-localizing proteins in SAR. PMID:27078071

  15. [Influence of Professional Contact with Plutonium-239 on Indicators of the Immune Status of the Personnel at Siberian Chemical Plant].

    PubMed

    Oradovskaya, I V; Radzivil, T T

    2015-01-01

    The results of the examination and monitoring of the personnel at the Siberian Chemical Plant (SChP) and adult population of Seversk are presented. The results of primary examination of the personnel who professionally contact the ionizing radiation (IR) from external sources and incorporated 239Pu showed that clinical symptoms of dysfunction of the immune system manifested themselves with a frequency of 75.30%. Infectious-inflammatory diseases (46.95%) and the combined pathology of infectious and allergic character (20.12%) were the most widespread. The allergic diseases (AD) without manifestations of an infectious component were observed not often (7.62%). The monitoring which was carried out for 10 years revealed a decrease in a percentage of persons with clinical signs of disorders of the immune system up to 60.68% among the personnel at the Chemical-Steel Plant and even more among the whole group of the studied personnel at SChP--49.68% (389 : 783). Among the population their frequency made up 51.78%. Features of clinical manifestations of dysfunction ofthe immune system depending on accumulation of 239Pu in the organism are established. Similar dynamics of infectious and infectious and allergic syndromes is revealed when the activity of 239Pu is 40 nCi. AD frequency reliably increased .when the activity of 239Pu is 20 nCi, but if accumulation is higher than 20-40 nCi it decreases and again increases when the activity is over 40 nCi. Pathologies of infectious and allergic genesis are most often observed when the content of 239Pu in an organism is over 40 nCi. Indicators of the immune status (IS) of the personnel at SChP with incorporated 239Pu are analyzed. 59 people--carriers of 239Pu and 408 people without 239Pu accumulated in an organism are examined. In comparison with the control, IS indicators characteristic for all dose loading groups are revealed: increase of lymphocytes, existence of dissociation in indicators of relative and absolute values of the T

  16. [Influence of Professional Contact with Plutonium-239 on Indicators of the Immune Status of the Personnel at Siberian Chemical Plant].

    PubMed

    Oradovskaya, I V; Radzivil, T T

    2015-01-01

    The results of the examination and monitoring of the personnel at the Siberian Chemical Plant (SChP) and adult population of Seversk are presented. The results of primary examination of the personnel who professionally contact the ionizing radiation (IR) from external sources and incorporated 239Pu showed that clinical symptoms of dysfunction of the immune system manifested themselves with a frequency of 75.30%. Infectious-inflammatory diseases (46.95%) and the combined pathology of infectious and allergic character (20.12%) were the most widespread. The allergic diseases (AD) without manifestations of an infectious component were observed not often (7.62%). The monitoring which was carried out for 10 years revealed a decrease in a percentage of persons with clinical signs of disorders of the immune system up to 60.68% among the personnel at the Chemical-Steel Plant and even more among the whole group of the studied personnel at SChP--49.68% (389 : 783). Among the population their frequency made up 51.78%. Features of clinical manifestations of dysfunction ofthe immune system depending on accumulation of 239Pu in the organism are established. Similar dynamics of infectious and infectious and allergic syndromes is revealed when the activity of 239Pu is 40 nCi. AD frequency reliably increased .when the activity of 239Pu is 20 nCi, but if accumulation is higher than 20-40 nCi it decreases and again increases when the activity is over 40 nCi. Pathologies of infectious and allergic genesis are most often observed when the content of 239Pu in an organism is over 40 nCi. Indicators of the immune status (IS) of the personnel at SChP with incorporated 239Pu are analyzed. 59 people--carriers of 239Pu and 408 people without 239Pu accumulated in an organism are examined. In comparison with the control, IS indicators characteristic for all dose loading groups are revealed: increase of lymphocytes, existence of dissociation in indicators of relative and absolute values of the T

  17. Community Immunity (Herd Immunity)

    MedlinePlus

    ... Content Marketing Share this: Main Content Area ​Community Immunity ("Herd" Immunity) Vaccines can prevent outbreaks of disease and save ... disease is contained. This is known as "community immunity." In the illustration below, the top box depicts ...

  18. Genetic requirements for signaling from an autoactive plant NB-LRR intracellular innate immune receptor.

    PubMed

    Roberts, Melinda; Tang, Saijun; Stallmann, Anna; Dangl, Jeffery L; Bonardi, Vera

    2013-01-01

    Plants react to pathogen attack via recognition of, and response to, pathogen-specific molecules at the cell surface and inside the cell. Pathogen effectors (virulence factors) are monitored by intracellular nucleotide-binding leucine-rich repeat (NB-LRR) sensor proteins in plants and mammals. Here, we study the genetic requirements for defense responses of an autoactive mutant of ADR1-L2, an Arabidopsis coiled-coil (CC)-NB-LRR protein. ADR1-L2 functions upstream of salicylic acid (SA) accumulation in several defense contexts, and it can act in this context as a "helper" to transduce specific microbial activation signals from "sensor" NB-LRRs. This helper activity does not require an intact P-loop. ADR1-L2 and another of two closely related members of this small NB-LRR family are also required for propagation of unregulated runaway cell death (rcd) in an lsd1 mutant. We demonstrate here that, in this particular context, ADR1-L2 function is P-loop dependent. We generated an autoactive missense mutation, ADR1-L2D484V, in a small homology motif termed MHD. Expression of ADR1-L2D848V leads to dwarfed plants that exhibit increased disease resistance and constitutively high SA levels. The morphological phenotype also requires an intact P-loop, suggesting that these ADR1-L2D484V phenotypes reflect canonical activation of this NB-LRR protein. We used ADR1-L2D484V to define genetic requirements for signaling. Signaling from ADR1-L2D484V does not require NADPH oxidase and is negatively regulated by EDS1 and AtMC1. Transcriptional regulation of ADR1-L2D484V is correlated with its phenotypic outputs; these outputs are both SA-dependent and -independent. The genetic requirements for ADR1-L2D484V activity resemble those that regulate an SA-gradient-dependent signal amplification of defense and cell death signaling initially observed in the absence of LSD1. Importantly, ADR1-L2D484V autoactivation signaling is controlled by both EDS1 and SA in separable, but linked pathways

  19. Plant-based porcine reproductive and respiratory syndrome virus VLPs induce an immune response in mice.

    PubMed

    Uribe-Campero, Laura; Monroy-García, Alberto; Durán-Meza, Ana L; Villagrana-Escareño, María V; Ruíz-García, Jaime; Hernández, Jesús; Núñez-Palenius, Héctor G; Gómez-Lim, Miguel A

    2015-10-01

    Porcine reproductive and respiratory syndrome virus (PRRSV) significantly affects the swine industry worldwide. An efficient, protective vaccine is still lacking. Here, we report for the first time the generation and purification of PRRSV virus like particles (VLPs) by expressing GP5, M and N genes in Nicotiana silvestris plants. The particles were clearly visible by transmission electron microscopy (TEM) with a size of 60-70 nm. Hydrodynamic diameter of the particles was obtained and it was confirmed that the VLPs had the appropriate size for PRRS virions and that the VLPs were highly pure. By measuring the Z potential we described the electrophoretic mobility behavior of VLPs and the best conditions for stability of the VLPs were determined. The particles were immunogenic in mice. A western blot of purified particles allowed detection of three coexpressed genes. These VLPs may serve as a platform to develop efficient PRRSV vaccines.

  20. Structural Analysis and Involvement in Plant Innate Immunity of Xanthomonas axonopodis pv. citri Lipopolysaccharide*

    PubMed Central

    Casabuono, Adriana; Petrocelli, Silvana; Ottado, Jorgelina; Orellano, Elena G.; Couto, Alicia S.

    2011-01-01

    Xanthomonas axonopodis pv. citri (Xac) causes citrus canker, provoking defoliation and premature fruit drop with concomitant economical damage. In plant pathogenic bacteria, lipopolysaccharides are important virulence factors, and they are being increasingly recognized as major pathogen-associated molecular patterns for plants. In general, three domains are recognized in a lipopolysaccharide: the hydrophobic lipid A, the hydrophilic O-antigen polysaccharide, and the core oligosaccharide, connecting lipid A and O-antigen. In this work, we have determined the structure of purified lipopolysaccharides obtained from Xanthomonas axonopodis pv. citri wild type and a mutant of the O-antigen ABC transporter encoded by the wzt gene. High pH anion exchange chromatography and matrix-assisted laser desorption/ionization mass spectrum analysis were performed, enabling determination of the structure not only of the released oligosaccharides and lipid A moieties but also the intact lipopolysaccharides. The results demonstrate that Xac wild type and Xacwzt LPSs are composed mainly of a penta- or tetra-acylated diglucosamine backbone attached to either two pyrophosphorylethanolamine groups or to one pyrophosphorylethanolamine group and one phosphorylethanolamine group. The core region consists of a branched oligosaccharide formed by Kdo2Hex6GalA3Fuc3NAcRha4 and two phosphate groups. As expected, the presence of a rhamnose homo-oligosaccharide as O-antigen was determined only in the Xac wild type lipopolysaccharide. In addition, we have examined how lipopolysaccharides from Xac function in the pathogenesis process. We analyzed the response of the different lipopolysaccharides during the stomata aperture closure cycle, the callose deposition, the expression of defense-related genes, and reactive oxygen species production in citrus leaves, suggesting a functional role of the O-antigen from Xac lipopolysaccharides in the basal response. PMID:21596742

  1. Structural analysis and involvement in plant innate immunity of Xanthomonas axonopodis pv. citri lipopolysaccharide.

    PubMed

    Casabuono, Adriana; Petrocelli, Silvana; Ottado, Jorgelina; Orellano, Elena G; Couto, Alicia S

    2011-07-22

    Xanthomonas axonopodis pv. citri (Xac) causes citrus canker, provoking defoliation and premature fruit drop with concomitant economical damage. In plant pathogenic bacteria, lipopolysaccharides are important virulence factors, and they are being increasingly recognized as major pathogen-associated molecular patterns for plants. In general, three domains are recognized in a lipopolysaccharide: the hydrophobic lipid A, the hydrophilic O-antigen polysaccharide, and the core oligosaccharide, connecting lipid A and O-antigen. In this work, we have determined the structure of purified lipopolysaccharides obtained from Xanthomonas axonopodis pv. citri wild type and a mutant of the O-antigen ABC transporter encoded by the wzt gene. High pH anion exchange chromatography and matrix-assisted laser desorption/ionization mass spectrum analysis were performed, enabling determination of the structure not only of the released oligosaccharides and lipid A moieties but also the intact lipopolysaccharides. The results demonstrate that Xac wild type and Xacwzt LPSs are composed mainly of a penta- or tetra-acylated diglucosamine backbone attached to either two pyrophosphorylethanolamine groups or to one pyrophosphorylethanolamine group and one phosphorylethanolamine group. The core region consists of a branched oligosaccharide formed by Kdo₂Hex₆GalA₃Fuc3NAcRha₄ and two phosphate groups. As expected, the presence of a rhamnose homo-oligosaccharide as O-antigen was determined only in the Xac wild type lipopolysaccharide. In addition, we have examined how lipopolysaccharides from Xac function in the pathogenesis process. We analyzed the response of the different lipopolysaccharides during the stomata aperture closure cycle, the callose deposition, the expression of defense-related genes, and reactive oxygen species production in citrus leaves, suggesting a functional role of the O-antigen from Xac lipopolysaccharides in the basal response. PMID:21596742

  2. Pepper Mild Mottle Virus, a Plant Virus Associated with Specific Immune Responses, Fever, Abdominal Pains, and Pruritus in Humans

    PubMed Central

    Colson, Philippe; Richet, Hervé; Desnues, Christelle; Balique, Fanny; Moal, Valérie; Grob, Jean-Jacques; Berbis, Philippe; Lecoq, Hervé; Harlé, Jean-Robert; Berland, Yvon; Raoult, Didier

    2010-01-01

    Background Recently, metagenomic studies have identified viable Pepper mild mottle virus (PMMoV), a plant virus, in the stool of healthy subjects. However, its source and role as pathogen have not been determined. Methods and Findings 21 commercialized food products containing peppers, 357 stool samples from 304 adults and 208 stool samples from 137 children were tested for PMMoV using real-time PCR, sequencing, and electron microscopy. Anti-PMMoV IgM antibody testing was concurrently performed. A case-control study tested the association of biological and clinical symptoms with the presence of PMMoV in the stool. Twelve (57%) food products were positive for PMMoV RNA sequencing. Stool samples from twenty-two (7.2%) adults and one child (0.7%) were positive for PMMoV by real-time PCR. Positive cases were significantly more likely to have been sampled in Dermatology Units (p<10−6), to be seropositive for anti-PMMoV IgM antibodies (p = 0.026) and to be patients who exhibited fever, abdominal pains, and pruritus (p = 0.045, 0.038 and 0.046, respectively). Conclusions Our study identified a local source of PMMoV and linked the presence of PMMoV RNA in stool with a specific immune response and clinical symptoms. Although clinical symptoms may be imputable to another cofactor, including spicy food, our data suggest the possibility of a direct or indirect pathogenic role of plant viruses in humans. PMID:20386604

  3. The Synthetic Elicitor 2-(5-Bromo-2-Hydroxy-Phenyl)-Thiazolidine-4-Carboxylic Acid Links Plant Immunity to Hormesis.

    PubMed

    Rodriguez-Salus, Melinda; Bektas, Yasemin; Schroeder, Mercedes; Knoth, Colleen; Vu, Trang; Roberts, Philip; Kaloshian, Isgouhi; Eulgem, Thomas

    2016-01-01

    Synthetic elicitors are drug-like compounds that induce plant immune responses but are structurally distinct from natural defense elicitors. Using high-throughput screening, we previously identified 114 synthetic elicitors that activate the expression of a pathogen-responsive reporter gene in Arabidopsis (Arabidopsis thaliana). Here, we report on the characterization of one of these compounds, 2-(5-bromo-2-hydroxy-phenyl)-thiazolidine-4-carboxylic acid (BHTC). BHTC induces disease resistance of plants against bacterial, oomycete, and fungal pathogens and has a unique mode of action and structure. Surprisingly, we found that low doses of BHTC enhanced root growth in Arabidopsis, while high doses of this compound inhibited root growth, besides inducing defense. These effects are reminiscent of the hormetic response, which is characterized by low-dose stimulatory effects of a wide range of agents that are toxic or inhibitory at higher doses. Like its effects on defense, BHTC-induced hormesis in Arabidopsis roots is partially dependent on the WRKY70 transcription factor. Interestingly, BHTC-induced root hormesis is also affected in the auxin-response mutants axr1-3 and slr-1. By messenger RNA sequencing, we uncovered a dramatic difference between transcriptional profiles triggered by low and high doses of BHTC. Only high levels of BHTC induce typical defense-related transcriptional changes. Instead, low BHTC levels trigger a coordinated intercompartmental transcriptional response manifested in the suppression of photosynthesis- and respiration-related genes in the nucleus, chloroplasts, and mitochondria as well as the induction of development-related nuclear genes. Taken together, our functional characterization of BHTC links defense regulation to hormesis and provides a hypothetical transcriptional scenario for the induction of hormetic root growth.

  4. Intron-hairpin RNA derived from replication associated protein C1 gene confers immunity to tomato yellow leaf curl virus infection in transgenic tomato plants.

    PubMed

    Fuentes, Alejandro; Ramos, Pedro L; Fiallo, Elvira; Callard, Danay; Sánchez, Yadira; Peral, Rudy; Rodríguez, Raidel; Pujol, Merardo

    2006-06-01

    The whitefly-transmitted Tomato Yellow Leaf Curl Virus (TYLCV) is the major pathogen of tomato crop in Cuba and one of the most outstanding viral diseases of plants worldwide. In this work, we have developed transgenic tomato plants, transformed with an intron-hairpin genetic construction to induce post- transcriptional gene silencing against the early TYLCV replication associated protein gene (C1). The intron-hairpin RNA produced involves 726 nts of the 3' end of the TYLCV C1 gene as the arms of the hairpin, and the castor bean catalase intron. Transgenic tomato plants belonging to line 126, which harbor a single transgene copy, showed immunity to TYLCV, even in extreme conditions of infection (4-leaf-stage plants and 300 to many hundreds viruliferous whiteflies per plant during 60 days). Dot blot hybridization of these plants showed no TYLCV DNA presence 60 days after inoculation. Small interfering RNA molecules were detected in both inoculated and non-inoculated plants from line 126. These transgenic tomato plants of the otherwise very TYLCV-susceptible Campbell-28 tomato cultivar, are the first report of resistance to a plant DNA virus obtained by the use of the intron-hairpin RNA approach. PMID:16779645

  5. Xanthomonas campestris cell–cell signalling molecule DSF (diffusible signal factor) elicits innate immunity in plants and is suppressed by the exopolysaccharide xanthan

    PubMed Central

    Kakkar, Akanksha; Nizampatnam, Narasimha Rao; Kondreddy, Anil; Pradhan, Binod Bihari; Chatterjee, Subhadeep

    2015-01-01

    Several secreted and surface-associated conserved microbial molecules are recognized by the host to mount the defence response. One such evolutionarily well-conserved bacterial process is the production of cell–cell signalling molecules which regulate production of multiple virulence functions by a process known as quorum sensing. Here it is shown that a bacterial fatty acid cell–cell signalling molecule, DSF (diffusible signal factor), elicits innate immunity in plants. The DSF family of signalling molecules are highly conserved among many phytopathogenic bacteria belonging to the genus Xanthomonas as well as in opportunistic animal pathogens. Using Arabidopsis, Nicotiana benthamiana, and rice as model systems, it is shown that DSF induces a hypersensitivity reaction (HR)-like response, programmed cell death, the accumulation of autofluorescent compounds, hydrogen peroxide production, and the expression of the PATHOGENESIS-RELATED1 (PR-1) gene. Furthermore, production of the DSF signalling molecule in Pseudomonas syringae, a non-DSF-producing plant pathogen, induces the innate immune response in the N. benthamiana host plant and also affects pathogen growth. By pre- and co-inoculation of DSF, it was demonstrated that the DSF-induced plant defence reduces disease severity and pathogen growth in the host plant. In this study, it was further demonstrated that wild-type Xanthomonas campestris suppresses the DSF-induced innate immunity by secreting xanthan, the main component of extracellular polysaccharide. The results indicate that plants have evolved to recognize a widely conserved bacterial communication system and may have played a role in the co-evolution of host recognition of the pathogen and the communication machinery. PMID:26248667

  6. Xanthomonas campestris cell-cell signalling molecule DSF (diffusible signal factor) elicits innate immunity in plants and is suppressed by the exopolysaccharide xanthan.

    PubMed

    Kakkar, Akanksha; Nizampatnam, Narasimha Rao; Kondreddy, Anil; Pradhan, Binod Bihari; Chatterjee, Subhadeep

    2015-11-01

    Several secreted and surface-associated conserved microbial molecules are recognized by the host to mount the defence response. One such evolutionarily well-conserved bacterial process is the production of cell-cell signalling molecules which regulate production of multiple virulence functions by a process known as quorum sensing. Here it is shown that a bacterial fatty acid cell-cell signalling molecule, DSF (diffusible signal factor), elicits innate immunity in plants. The DSF family of signalling molecules are highly conserved among many phytopathogenic bacteria belonging to the genus Xanthomonas as well as in opportunistic animal pathogens. Using Arabidopsis, Nicotiana benthamiana, and rice as model systems, it is shown that DSF induces a hypersensitivity reaction (HR)-like response, programmed cell death, the accumulation of autofluorescent compounds, hydrogen peroxide production, and the expression of the PATHOGENESIS-RELATED1 (PR-1) gene. Furthermore, production of the DSF signalling molecule in Pseudomonas syringae, a non-DSF-producing plant pathogen, induces the innate immune response in the N. benthamiana host plant and also affects pathogen growth. By pre- and co-inoculation of DSF, it was demonstrated that the DSF-induced plant defence reduces disease severity and pathogen growth in the host plant. In this study, it was further demonstrated that wild-type Xanthomonas campestris suppresses the DSF-induced innate immunity by secreting xanthan, the main component of extracellular polysaccharide. The results indicate that plants have evolved to recognize a widely conserved bacterial communication system and may have played a role in the co-evolution of host recognition of the pathogen and the communication machinery.

  7. A Noncanonical Role for the CKI-RB-E2F Cell Cycle Signaling Pathway in Plant Effector-Triggered Immunity

    PubMed Central

    Wang, Shui; Gu, Yangnan; Zebell, Sophia G.; Anderson, Lisa K.; Wang, Wei; Mohan, Rajinikanth; Dong, Xinnian

    2014-01-01

    SUMMARY Effector-triggered immunity (ETI), the major host defense mechanism in plants, is often associated with programmed cell death (PCD). Plants lack close homologs of caspases, the key mediators of PCD in animals. So although the NB-LRR receptors involved in ETI are well studied, how they activate PCD and confer disease resistance remains elusive. We show that the Arabidopsis nuclear envelope protein, CPR5, negatively regulates ETI and the associated PCD through a physical interaction with CYCLIN-DEPENDENT KINASE INHIBITORs (CKIs). Upon ETI induction, CKIs are released from CPR5 to cause over-activation of another core cell cycle regulator, E2F. In cki and e2f mutants, ETI responses induced by both TIR-NB-LRR and CC-NB-LRR classes of immune receptors are compromised. We further show that E2F is deregulated during ETI probably through CKI-mediated hyperphosphorylation of RETINOBLASTOMA-RELATED 1 (RBR1). This study demonstrates that canonical cell cycle regulators also play important noncanonical roles in plant immunity. PMID:25455564

  8. Plant innate immunity induced by flagellin suppresses the hypersensitive response in non-host plants elicited by Pseudomonas syringae pv. averrhoi.

    PubMed

    Wei, Chia-Fong; Hsu, Shih-Tien; Deng, Wen-Ling; Wen, Yu-Der; Huang, Hsiou-Chen

    2012-01-01

    A new pathogen, Pseudomonas syringae pv. averrhoi (Pav), which causes bacterial spot disease on carambola was identified in Taiwan in 1997. Many strains of this pathovar have been isolated from different locations and several varieties of hosts. Some of these strains, such as HL1, are nonmotile and elicit a strong hypersensitive response (HR) in nonhost tobacco leaves, while other strains, such as PA5, are motile and elicit a weak HR. Based on the image from a transmission electron microscope, the results showed that HL1 is flagellum-deficient and PA5 has normal flagella. Here we cloned and analyzed the fliC gene and glycosylation island from Pav HL1 and PA5. The amino acid sequences of FliC from HL1 and PA5 are identical to P. s. pvs. tabaci (Pta), glycinea and phaseolicola and share very high similarity with other pathovars of P. syringae. In contrast to the flagellin mutant PtaΔfliC, PA5ΔfliC grows as well as wild type in the host plant, but it elicits stronger HR than wild type does in non-host plants. Furthermore, the purified Pav flagellin, but not the divergent flagellin from Agrobacterium tumefaciens, is able to impair the HR induced by PA5ΔfliC. PA5Δfgt1 possessing nonglycosylated flagella behaved as its wild type in both bacterial growth in host and HR elicitation. Flagellin was infiltrated into tobacco leaves either simultaneously with flagellum-deficient HL1 or prior to the inoculation of wild type HL1, and both treatments impaired the HR induced by HL1. Moreover, the HR elicited by PA5 and PA5ΔfliC was enhanced by the addition of cycloheximide, suggesting that the flagellin is one of the PAMPs (pathogen-associated molecular patterns) contributed to induce the PAMP-triggered immunity (PTI). Taken together, the results shown in this study reveal that flagellin in Pav is capable of suppressing HR via PTI induction during an incompatible interaction.

  9. Plant innate immunity induced by flagellin suppresses the hypersensitive response in non-host plants elicited by Pseudomonas syringae pv. averrhoi.

    PubMed

    Wei, Chia-Fong; Hsu, Shih-Tien; Deng, Wen-Ling; Wen, Yu-Der; Huang, Hsiou-Chen

    2012-01-01

    A new pathogen, Pseudomonas syringae pv. averrhoi (Pav), which causes bacterial spot disease on carambola was identified in Taiwan in 1997. Many strains of this pathovar have been isolated from different locations and several varieties of hosts. Some of these strains, such as HL1, are nonmotile and elicit a strong hypersensitive response (HR) in nonhost tobacco leaves, while other strains, such as PA5, are motile and elicit a weak HR. Based on the image from a transmission electron microscope, the results showed that HL1 is flagellum-deficient and PA5 has normal flagella. Here we cloned and analyzed the fliC gene and glycosylation island from Pav HL1 and PA5. The amino acid sequences of FliC from HL1 and PA5 are identical to P. s. pvs. tabaci (Pta), glycinea and phaseolicola and share very high similarity with other pathovars of P. syringae. In contrast to the flagellin mutant PtaΔfliC, PA5ΔfliC grows as well as wild type in the host plant, but it elicits stronger HR than wild type does in non-host plants. Furthermore, the purified Pav flagellin, but not the divergent flagellin from Agrobacterium tumefaciens, is able to impair the HR induced by PA5ΔfliC. PA5Δfgt1 possessing nonglycosylated flagella behaved as its wild type in both bacterial growth in host and HR elicitation. Flagellin was infiltrated into tobacco leaves either simultaneously with flagellum-deficient HL1 or prior to the inoculation of wild type HL1, and both treatments impaired the HR induced by HL1. Moreover, the HR elicited by PA5 and PA5ΔfliC was enhanced by the addition of cycloheximide, suggesting that the flagellin is one of the PAMPs (pathogen-associated molecular patterns) contributed to induce the PAMP-triggered immunity (PTI). Taken together, the results shown in this study reveal that flagellin in Pav is capable of suppressing HR via PTI induction during an incompatible interaction. PMID:22911741

  10. The LOV Protein of Xanthomonas citri subsp. citri Plays a Significant Role in the Counteraction of Plant Immune Responses during Citrus Canker

    PubMed Central

    Kraiselburd, Ivana; Daurelio, Lucas D.; Tondo, María Laura; Merelo, Paz; Cortadi, Adriana A.; Talón, Manuel; Tadeo, Francisco R.; Orellano, Elena G.

    2013-01-01

    Pathogens interaction with a host plant starts a set of immune responses that result in complex changes in gene expression and plant physiology. Light is an important modulator of plant defense response and recent studies have evidenced the novel influence of this environmental stimulus in the virulence of several bacterial pathogens. Xanthomonas citri subsp. citri is the bacterium responsible for citrus canker disease, which affects most citrus cultivars. The ability of this bacterium to colonize host plants is influenced by bacterial blue-light sensing through a LOV-domain protein and disease symptoms are considerably altered upon deletion of this protein. In this work we aimed to unravel the role of this photoreceptor during the bacterial counteraction of plant immune responses leading to citrus canker development. We performed a transcriptomic analysis in Citrus sinensis leaves inoculated with the wild type X. citri subsp. citri and with a mutant strain lacking the LOV protein by a cDNA microarray and evaluated the differentially regulated genes corresponding to specific biological processes. A down-regulation of photosynthesis-related genes (together with a corresponding decrease in photosynthesis rates) was observed upon bacterial infection, this effect being more pronounced in plants infected with the lov-mutant bacterial strain. Infection with this strain was also accompanied with the up-regulation of several secondary metabolism- and defense response-related genes. Moreover, we found that relevant plant physiological alterations triggered by pathogen attack such as cell wall fortification and tissue disruption were amplified during the lov-mutant strain infection. These results suggest the participation of the LOV-domain protein from X. citri subsp. citri in the bacterial counteraction of host plant defense response, contributing in this way to disease development. PMID:24260514

  11. Plant-derived H7 VLP vaccine elicits protective immune response against H7N9 influenza virus in mice and ferrets.

    PubMed

    Pillet, S; Racine, T; Nfon, C; Di Lenardo, T Z; Babiuk, S; Ward, B J; Kobinger, G P; Landry, N

    2015-11-17

    In March 2013, the Chinese Centre for Disease Control and Prevention confirmed the first reported case of human infection with an avian influenza A H7N9 virus. Infection with this virus often caused severe pneumonia and acute respiratory distress syndrome resulting in a case fatality rate >35%. The risk of pandemic highlighted, once again, the need for a more rapid and scalable vaccine response capability. Here, we describe the rapid (19 days) development of a plant-derived VLP vaccine based on the hemagglutinin sequence of influenza H7N9 A/Hangzhou/1/2013. The immunogenicity of the H7 VLP vaccine was assessed in mice and ferrets after one or two intramuscular dose(s) with and without adjuvant (alum or GLA-SE™). In ferrets, we also measured H7-specific cell-mediated immunity. The mice and ferrets were then challenged with H7N9 A/Anhui/1/2013 influenza virus. A single immunization with the adjuvanted vaccine elicited a strong humoral response and protected mice against an otherwise lethal challenge. Two doses of unadjuvanted vaccine significantly increased humoral response and resulted in 100% protection with significant reduction of clinical signs leading to nearly asymptomatic infections. In ferrets, a single immunization with the alum-adjuvanted H7 VLP vaccine induced strong humoral and CMI responses with antigen-specific activation of CD3(+) T cells. Compared to animals injected with placebo, ferrets vaccinated with alum-adjuvanted vaccine displayed no weight loss during the challenge. Moreover, the vaccination significantly reduced the viral load in lungs and nasal washes 3 days after the infection. This candidate plant-made H7 vaccine therefore induced protective responses after either one adjuvanted or two unadjuvanted doses. Studies are currently ongoing to better characterize the immune response elicited by the plant-derived VLP vaccines. Regardless, these data are very promising for the rapid production of an immunogenic and protective vaccine against

  12. Structures of the flax-rust effector AvrM reveal insights into the molecular basis of plant-cell entry and effector-triggered immunity.

    PubMed

    Ve, Thomas; Williams, Simon J; Catanzariti, Ann-Maree; Rafiqi, Maryam; Rahman, Motiur; Ellis, Jeffrey G; Hardham, Adrienne R; Jones, David A; Anderson, Peter A; Dodds, Peter N; Kobe, Bostjan

    2013-10-22

    Fungal and oomycete pathogens cause some of the most devastating diseases in crop plants, and facilitate infection by delivering a large number of effector molecules into the plant cell. AvrM is a secreted effector protein from flax rust (Melampsora lini) that can internalize into plant cells in the absence of the pathogen, binds to phosphoinositides (PIPs), and is recognized directly by the resistance protein M in flax (Linum usitatissimum), resulting in effector-triggered immunity. We determined the crystal structures of two naturally occurring variants of AvrM, AvrM-A and avrM, and both reveal an L-shaped fold consisting of a tandem duplicated four-helix motif, which displays similarity to the WY domain core in oomycete effectors. In the crystals, both AvrM variants form a dimer with an unusual nonglobular shape. Our functional analysis of AvrM reveals that a hydrophobic surface patch conserved between both variants is required for internalization into plant cells, whereas the C-terminal coiled-coil domain mediates interaction with M. AvrM binding to PIPs is dependent on positive surface charges, and mutations that abrogate PIP binding have no significant effect on internalization, suggesting that AvrM binding to PIPs is not essential for transport of AvrM across the plant membrane. The structure of AvrM and the identification of functionally important surface regions advance our understanding of the molecular mechanisms underlying how effectors enter plant cells and how they are detected by the plant immune system.

  13. Analysis of new type III effectors from Xanthomonas uncovers XopB and XopS as suppressors of plant immunity.

    PubMed

    Schulze, Sebastian; Kay, Sabine; Büttner, Daniela; Egler, Monique; Eschen-Lippold, Lennart; Hause, Gerd; Krüger, Antje; Lee, Justin; Müller, Oliver; Scheel, Dierk; Szczesny, Robert; Thieme, Frank; Bonas, Ulla

    2012-09-01

    The pathogenicity of the Gram-negative plant-pathogenic bacterium Xanthomonas campestris pv. vesicatoria (Xcv) is dependent on type III effectors (T3Es) that are injected into plant cells by a type III secretion system and interfere with cellular processes to the benefit of the pathogen. In this study, we analyzed eight T3Es from Xcv strain 85-10, six of which were newly identified effectors. Genetic studies and protoplast expression assays revealed that XopB and XopS contribute to disease symptoms and bacterial growth, and suppress pathogen-associated molecular pattern (PAMP)-triggered plant defense gene expression. In addition, XopB inhibits cell death reactions induced by different T3Es, thus suppressing defense responses related to both PAMP-triggered immunity (PTI) and effector-triggered immunity (ETI). XopB localizes to the Golgi apparatus and cytoplasm of the plant cell and interferes with eukaryotic vesicle trafficking. Interestingly, a XopB point mutant derivative was defective in the suppression of ETI-related responses, but still interfered with vesicle trafficking and was only slightly affected with regard to the suppression of defense gene induction. This suggests that XopB-mediated suppression of PTI and ETI is dependent on different mechanisms that can be functionally separated. PMID:22738163

  14. ENHANCED DISEASE RESISTANCE4 Associates with CLATHRIN HEAVY CHAIN2 and Modulates Plant Immunity by Regulating Relocation of EDR1 in Arabidopsis

    PubMed Central

    Wu, Guangheng; Liu, Simu; Zhao, Yaofei; Wang, Wei; Kong, Zhaosheng; Tang, Dingzhong

    2015-01-01

    Obligate biotrophs, such as the powdery mildew pathogens, deliver effectors to the host cell and obtain nutrients from the infection site. The interface between the plant host and the biotrophic pathogen thus represents a major battleground for plant-pathogen interactions. Increasing evidence shows that cellular trafficking plays an important role in plant immunity. Here, we report that Arabidopsis thaliana ENHANCED DISEASE RESISTANCE4 (EDR4) plays a negative role in resistance to powdery mildew and that the enhanced disease resistance in edr4 mutants requires salicylic acid signaling. EDR4 mainly localizes to the plasma membrane and endosomal compartments. Genetic analyses show that EDR4 and EDR1 function in the same genetic pathway. EDR1 and EDR4 accumulate at the penetration site of powdery mildew infection, and EDR4 physically interacts with EDR1, recruiting EDR1 to the fungal penetration site. In addition, EDR4 interacts with CLATHRIN HEAVY CHAIN2 (CHC2), and edr4 mutants show reduced endocytosis rates. Taken together, our data indicate that EDR4 associates with CHC2 and modulates plant immunity by regulating the relocation of EDR1 in Arabidopsis. PMID:25747881

  15. Splicing of Receptor-Like Kinase-Encoding SNC4 and CERK1 is Regulated by Two Conserved Splicing Factors that Are Required for Plant Immunity

    PubMed Central

    Zhang, Zhibin; Liu, Yanan; Ding, Pingtao; Li, Yan; Kong, Qing; Zhang, Yuelin

    2014-01-01

    Plant immune receptors belonging to the receptor-like kinase (RLK) family play important roles in the recognition of microbial pathogens and activation of downstream defense responses. The Arabidopsis mutant snc4-1D contains a gain-of-function mutation in the RLK SNC4 (SUPPRESSOR OF NPR1-1, CONSTITUTIVE4), which leads to constitutive activation of defense responses. Analysis of suppressor mutants of snc4-1D identified two conserved splicing factors, SUA (SUPPRESSOR OF ABI3-5) and RSN2 (REQUIRED FOR SNC4-1D 2), that are required for the constitutive defense responses in snc4-1D. In sua and rsn2 mutants, SNC4 splicing is altered and the amount of SNC4 transcripts is reduced. Further analysis showed that SUA and RSN2 are also required for the proper splicing of CERK1 (CHITIN ELICITOR RECEPTOR KINASE1), which encodes another RLK that functions as a receptor for chitin. In sua and rsn2 mutants, induction of reactive oxygen species by chitin is reduced and the non-pathogenic bacteria Pseudomonas syringae pv. tomato DC3000hrcC grows to higher titers than in wild-type plants. Our study suggests that pre-mRNA splicing plays important roles in the regulation of plant immunity mediated by the RLKs SNC4 and CERK1. PMID:25267732

  16. The Ankyrin-Repeat Transmembrane Protein BDA1 Functions Downstream of the Receptor-Like Protein SNC2 to Regulate Plant Immunity1[C][OA

    PubMed Central

    Yang, Yuanai; Zhang, Yaxi; Ding, Pingtao; Johnson, Kaeli; Li, Xin; Zhang, Yuelin

    2012-01-01

    Plants utilize a large number of immune receptors to recognize pathogens and activate defense responses. A small number of these receptors belong to the receptor-like protein family. Previously, we showed that a gain-of-function mutation in the receptor-like protein SNC2 (for Suppressor of NPR1, Constitutive2) leads to constitutive activation of defense responses in snc2-1D mutant plants. To identify defense signaling components downstream of SNC2, we carried out a suppressor screen in the snc2-1D mutant background of Arabidopsis (Arabidopsis thaliana). Map-based cloning of one of the suppressor genes, BDA1 (for bian da; “becoming big” in Chinese), showed that it encodes a protein with amino-terminal ankyrin repeats and carboxyl-terminal transmembrane domains. Loss-of-function mutations in BDA1 suppress the dwarf morphology and constitutive defense responses in snc2-1D npr1-1 (for nonexpressor of pathogenesis-related genes1,1) and also result in enhanced susceptibility to bacterial pathogens. In contrast, a gain-of-function allele of bda1 isolated from a separate genetic screen to search for mutants with enhanced pathogen resistance was found to constitutively activate cell death and defense responses. These data suggest that BDA1 is a critical signaling component that functions downstream of SNC2 to regulate plant immunity. PMID:22740615

  17. Splicing of receptor-like kinase-encoding SNC4 and CERK1 is regulated by two conserved splicing factors that are required for plant immunity.

    PubMed

    Zhang, Zhibin; Liu, Yanan; Ding, Pingtao; Li, Yan; Kong, Qing; Zhang, Yuelin

    2014-12-01

    Plant immune receptors belonging to the receptor-like kinase (RLK) family play important roles in the recognition of microbial pathogens and activation of downstream defense responses. The Arabidopsis mutant snc4-1D contains a gain-of-function mutation in the RLK SNC4 (SUPPRESSOR OF NPR1-1, CONSTITUTIVE4), which leads to constitutive activation of defense responses. Analysis of suppressor mutants of snc4-1D identified two conserved splicing factors, SUA (SUPPRESSOR OF ABI3-5) and RSN2 (REQUIRED FOR SNC4-1D 2), that are required for the constitutive defense responses in snc4-1D. In sua and rsn2 mutants, SNC4 splicing is altered and the amount of SNC4 transcripts is reduced. Further analysis showed that SUA and RSN2 are also required for the proper splicing of CERK1 (CHITIN ELICITOR RECEPTOR KINASE1), which encodes another RLK that functions as a receptor for chitin. In sua and rsn2 mutants, induction of reactive oxygen species by chitin is reduced and the non-pathogenic bacteria Pseudomonas syringae pv. tomato DC3000hrcC grows to higher titers than in wild-type plants. Our study suggests that pre-mRNA splicing plays important roles in the regulation of plant immunity mediated by the RLKs SNC4 and CERK1. PMID:25267732

  18. Plant Aquaporin AtPIP1;4 Links Apoplastic H2O2 Induction to Disease Immunity Pathways1[OPEN

    PubMed Central

    Tian, Shan; Wang, Xiaobing; Li, Ping; Wang, Hao; Ji, Hongtao; Xie, Junyi; Qiu, Qinglei

    2016-01-01

    Hydrogen peroxide (H2O2) is a stable component of reactive oxygen species, and its production in plants represents the successful recognition of pathogen infection and pathogen-associated molecular patterns (PAMPs). This production of H2O2 is typically apoplastic but is subsequently associated with intracellular immunity pathways that regulate disease resistance, such as systemic acquired resistance and PAMP-triggered immunity. Here, we elucidate that an Arabidopsis (Arabidopsis thaliana) aquaporin (i.e. the plasma membrane intrinsic protein AtPIP1;4) acts to close the cytological distance between H2O2 production and functional performance. Expression of the AtPIP1;4 gene in plant leaves is inducible by a bacterial pathogen, and the expression accompanies H2O2 accumulation in the cytoplasm. Under de novo expression conditions, AtPIP1;4 is able to mediate the translocation of externally applied H2O2 into the cytoplasm of yeast (Saccharomyces cerevisiae) cells. In plant cells treated with H2O2, AtPIP1;4 functions as an effective facilitator of H2O2 transport across plasma membranes and mediates the translocation of externally applied H2O2 from the apoplast to the cytoplasm. The H2O2-transport role of AtPIP1;4 is essentially required for the cytoplasmic import of apoplastic H2O2 induced by the bacterial pathogen and two typical PAMPs in the absence of induced production of intracellular H2O2. As a consequence, cytoplasmic H2O2 quantities increase substantially while systemic acquired resistance and PAMP-triggered immunity are activated to repress the bacterial pathogenicity. By contrast, loss-of-function mutation at the AtPIP1;4 gene locus not only nullifies the cytoplasmic import of pathogen- and PAMP-induced apoplastic H2O2 but also cancels the subsequent immune responses, suggesting a pivotal role of AtPIP1;4 in apocytoplastic signal transduction in immunity pathways. PMID:26945050

  19. The Tomato Calcium Sensor Cbl10 and Its Interacting Protein Kinase Cipk6 Define a Signaling Pathway in Plant Immunity[C][W

    PubMed Central

    de la Torre, Fernando; Gutiérrez-Beltrán, Emilio; Pareja-Jaime, Yolanda; Chakravarthy, Suma; Martin, Gregory B.; del Pozo, Olga

    2013-01-01

    Ca2+ signaling is an early and necessary event in plant immunity. The tomato (Solanum lycopersicum) kinase Pto triggers localized programmed cell death (PCD) upon recognition of Pseudomonas syringae effectors AvrPto or AvrPtoB. In a virus-induced gene silencing screen in Nicotiana benthamiana, we independently identified two components of a Ca2+-signaling system, Cbl10 (for calcineurin B-like protein) and Cipk6 (for calcineurin B-like interacting protein kinase), as their silencing inhibited Pto/AvrPto-elicited PCD. N. benthamiana Cbl10 and Cipk6 are also required for PCD triggered by other plant resistance genes and virus, oomycete, and nematode effectors and for host susceptibility to two P. syringae pathogens. Tomato Cipk6 interacts with Cbl10 and its in vitro kinase activity is enhanced in the presence of Cbl10 and Ca2+, suggesting that tomato Cbl10 and Cipk6 constitute a Ca2+-regulated signaling module. Overexpression of tomato Cipk6 in N. benthamiana leaves causes accumulation of reactive oxygen species (ROS), which requires the respiratory burst homolog RbohB. Tomato Cbl10 and Cipk6 interact with RbohB at the plasma membrane. Finally, Cbl10 and Cipk6 contribute to ROS generated during effector-triggered immunity in the interaction of P. syringae pv tomato DC3000 and N. benthamiana. We identify a role for the Cbl/Cipk signaling module in PCD, establishing a mechanistic link between Ca2+ and ROS signaling in plant immunity. PMID:23903322

  20. Immune System

    MedlinePlus

    ... How Can I Help a Friend Who Cuts? Immune System KidsHealth > For Teens > Immune System Print A A ... could put us out of commission. What the Immune System Does The immune (pronounced: ih-MYOON) system, which ...

  1. Assessment of Some Immune Parameters in Occupationally Exposed Nuclear Power Plants Workers: Flowcytometry Measurements of T, B, NK and NKT Cells.

    PubMed

    Gyuleva, Ilona; Panova, Delyana; Djounova, Jana; Rupova, Ivanka; Penkova, Kalina

    2015-01-01

    The purpose of this article is to analyze the results of a 10-year survey of the radiation effects of some immune parameters of occupationally exposed personnel from the Nuclear Power Plant "Kozloduy", Bulgaria. 438 persons working in NPP with cumulative doses between 0.06 mSv and 766.36mSv and a control group with 65 persons were studied. Flow cytometry measurements of T, B, natural killer (NK) and natural killer T (NKT) cell lymphocyte populations were performed. Data were interpreted with regard to cumulative doses, length of service and age. The average values of the studied parameters of cellular immunity were in the reference range relative to age and for most of the workers were not significantly different from the control values. Low doses of ionizing radiation showed some trends of change in the number of CD3+CD4+ helper-inducer lymphocytes, CD3+ CD8+ and NKT cell counts. The observed changes in some of the studied parameters could be interpreted in terms of adaptation processes at low doses. At doses above 100-200 mSv, compensatory mechanisms might be involved to balance deviations in lymphocyte subsets. The observed variations in some cases could not be attributed only to the radiation exposure because of the impact of a number of other exogenous and endogenous factors on the immune system. PMID:26675014

  2. Plant-derived H7 VLP vaccine elicits protective immune response against H7N9 influenza virus in mice and ferrets.

    PubMed

    Pillet, S; Racine, T; Nfon, C; Di Lenardo, T Z; Babiuk, S; Ward, B J; Kobinger, G P; Landry, N

    2015-11-17

    In March 2013, the Chinese Centre for Disease Control and Prevention confirmed the first reported case of human infection with an avian influenza A H7N9 virus. Infection with this virus often caused severe pneumonia and acute respiratory distress syndrome resulting in a case fatality rate >35%. The risk of pandemic highlighted, once again, the need for a more rapid and scalable vaccine response capability. Here, we describe the rapid (19 days) development of a plant-derived VLP vaccine based on the hemagglutinin sequence of influenza H7N9 A/Hangzhou/1/2013. The immunogenicity of the H7 VLP vaccine was assessed in mice and ferrets after one or two intramuscular dose(s) with and without adjuvant (alum or GLA-SE™). In ferrets, we also measured H7-specific cell-mediated immunity. The mice and ferrets were then challenged with H7N9 A/Anhui/1/2013 influenza virus. A single immunization with the adjuvanted vaccine elicited a strong humoral response and protected mice against an otherwise lethal challenge. Two doses of unadjuvanted vaccine significantly increased humoral response and resulted in 100% protection with significant reduction of clinical signs leading to nearly asymptomatic infections. In ferrets, a single immunization with the alum-adjuvanted H7 VLP vaccine induced strong humoral and CMI responses with antigen-specific activation of CD3(+) T cells. Compared to animals injected with placebo, ferrets vaccinated with alum-adjuvanted vaccine displayed no weight loss during the challenge. Moreover, the vaccination significantly reduced the viral load in lungs and nasal washes 3 days after the infection. This candidate plant-made H7 vaccine therefore induced protective responses after either one adjuvanted or two unadjuvanted doses. Studies are currently ongoing to better characterize the immune response elicited by the plant-derived VLP vaccines. Regardless, these data are very promising for the rapid production of an immunogenic and protective vaccine against

  3. Crystallization and preliminary crystallographic analysis of Arabidopsis thaliana EDS1, a key component of plant immunity, in complex with its signalling partner SAG101.

    PubMed

    Wagner, Stephan; Rietz, Steffen; Parker, Jane E; Niefind, Karsten

    2011-02-01

    In plants, the nucleocytoplasmic protein EDS1 (Enhanced disease susceptibility1) is an important regulator of innate immunity, coordinating host-cell defence and cell-death programs in response to pathogen attack. Arabidopsis thaliana EDS1 stabilizes and signals together with its partners PAD4 (Phytoalexin deficient4) and SAG101 (Senescence-associated gene101). Characterization of EDS1 molecular configurations in vitro and in vivo points to the formation of structurally and spatially distinct EDS1 homomeric dimers and EDS1 heteromeric complexes with either PAD4 or SAG101 as necessary components of the immune response. EDS1, PAD4 and SAG101 constitute a plant-specific protein family with a unique `EP' (EDS1-PAD4-specific) domain at their C-termini and an N-terminal domain resembling enzymes with an α/β-hydrolase fold. Here, the expression, purification and crystallization of a functional EDS1 complex formed by EDS1 and SAG101 from Arabidopsis thaliana are reported. The crystals belonged to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 101.8, b = 115.9, c = 122.8 Å, and diffracted to 3.5 Å resolution.

  4. Comparative analyses of genotype dependent expressed sequence tags and stress-responsive transcriptome of chickpea wilt illustrate predicted and unexpected genes and novel regulators of plant immunity

    PubMed Central

    Ashraf, Nasheeman; Ghai, Deepali; Barman, Pranjan; Basu, Swaraj; Gangisetty, Nagaraju; Mandal, Mihir K; Chakraborty, Niranjan; Datta, Asis; Chakraborty, Subhra

    2009-01-01

    Background The ultimate phenome of any organism is modulated by regulated transcription of many genes. Characterization of genetic makeup is thus crucial for understanding the molecular basis of phenotypic diversity, evolution and response to intra- and extra-cellular stimuli. Chickpea is the world's third most important food legume grown in over 40 countries representing all the continents. Despite its importance in plant evolution, role in human nutrition and stress adaptation, very little ESTs and differential transcriptome data is available, let alone genotype-specific gene signatures. Present study focuses on Fusarium wilt responsive gene expression in chickpea. Results We report 6272 gene sequences of immune-response pathway that would provide genotype-dependent spatial information on the presence and relative abundance of each gene. The sequence assembly led to the identification of a CaUnigene set of 2013 transcripts comprising of 973 contigs and 1040 singletons, two-third of which represent new chickpea genes hitherto undiscovered. We identified 209 gene families and 262 genotype-specific SNPs. Further, several novel transcription regulators were identified indicating their possible role in immune response. The transcriptomic analysis revealed 649 non-cannonical genes besides many unexpected candidates with known biochemical functions, which have never been associated with pathostress-responsive transcriptome. Conclusion Our study establishes a comprehensive catalogue of the immune-responsive root transcriptome with insight into their identity and function. The development, detailed analysis of CaEST datasets and global gene expression by microarray provide new insight into the commonality and diversity of organ-specific immune-responsive transcript signatures and their regulated expression shaping the species specificity at genotype level. This is the first report on differential transcriptome of an unsequenced genome during vascular wilt. PMID:19732460

  5. Arabidopsis thaliana plants expressing Rift Valley fever virus antigens: Mice exhibit systemic immune responses as the result of oral administration of the transgenic plants.

    PubMed

    Kalbina, Irina; Lagerqvist, Nina; Moiane, Bélisario; Ahlm, Clas; Andersson, Sören; Strid, Åke; Falk, Kerstin I

    2016-11-01

    The zoonotic Rift Valley fever virus affects livestock and humans in Africa and on the Arabian Peninsula. The economic impact of this pathogen due to livestock losses, as well as its relevance to public health, underscores the importance of developing effective and easily distributed vaccines. Vaccines that can be delivered orally are of particular interest. Here, we report the expression in transformed plants (Arabidopsis thaliana) of Rift Valley fever virus antigens. The antigens used in this study were the N protein and a deletion mutant of the Gn glycoprotein. Transformed lines were analysed for specific mRNA and protein content by RT-PCR and Western blotting, respectively. Furthermore, the plant-expressed antigens were evaluated for their immunogenicity in mice fed the transgenic plants. After oral intake of fresh transgenic plant material, a proportion of the mice elicited specific IgG antibody responses, as compared to the control animals that were fed wild-type plants and of which none sero-converted. Thus, we show that transgenic plants can be readily used to express and produce Rift Valley Fever virus proteins, and that the plants are immunogenic when given orally to mice. These are promising findings and provide a basis for further studies on edible plant vaccines against the Rift Valley fever virus.

  6. A Phytophthora sojae effector PsCRN63 forms homo-/hetero-dimers to suppress plant immunity via an inverted association manner

    PubMed Central

    Li, Qi; Zhang, Meixiang; Shen, Danyu; Liu, Tingli; Chen, Yanyu; Zhou, Jian-Min; Dou, Daolong

    2016-01-01

    Oomycete pathogens produce a large number of effectors to promote infection. Their mode of action are largely unknown. Here we show that a Phytophthora sojae effector, PsCRN63, suppresses flg22-induced expression of FRK1 gene, a molecular marker in pathogen-associated molecular patterns (PAMP)-triggered immunity (PTI). However, PsCRN63 does not suppress upstream signaling events including flg22-induced MAPK activation and BIK1 phosphorylation, indicating that it acts downstream of MAPK cascades. The PsCRN63-transgenic Arabidopsis plants showed increased susceptibility to bacterial pathogen Pseudomonas syringae pathovar tomato (Pst) DC3000 and oomycete pathogen Phytophthora capsici. The callose deposition were suppressed in PsCRN63-transgenic plants compared with the wild-type control plants. Genes involved in PTI were also down-regulated in PsCRN63-transgenic plants. Interestingly, we found that PsCRN63 forms an dimer that is mediated by inter-molecular interactions between N-terminal and C-terminal domains in an inverted association manner. Furthermore, the N-terminal and C-terminal domains required for the dimerization are widely conserved among CRN effectors, suggesting that homo-/hetero-dimerization of Phytophthora CRN effectors is required to exert biological functions. Indeed, the dimerization was required for PTI suppression and cell death-induction activities of PsCRN63. PMID:27243217

  7. Trichoderma-induced plant immunity likely involves both hormonal- and camalexin-dependent mechanisms in Arabidopsis thaliana and confers resistance against necrotrophic fungi Botrytis cinerea.

    PubMed

    Contreras-Cornejo, Hexon Angel; Macías-Rodríguez, Lourdes; Beltrán-Peña, Elda; Herrera-Estrella, Alfredo; López-Bucio, José

    2011-10-01

    Filamentous fungi belonging to the genus Trichoderma have long been recognized as agents for the biocontrol of plant diseases. In this work, we investigated the mechanisms involved in the defense responses of Arabidopsis thaliana seedlings elicited by co-culture with Trichoderma virens and Trichoderma atroviride. Interaction of plant roots with fungal mycelium induced growth and defense responses, indicating that both processes are not inherently antagonist. Expression studies of the pathogenesis-related reporter markers pPr1a:uidA and pLox2:uidA in response to T. virens or T. atroviride provided evidence that the defense signaling pathway activated by these fungi involves salicylic acid (SA) and/or jasmonic acid (JA) depending on the amount of conidia inoculated. Moreover, we found that Arabidopsis seedlings colonized by Trichoderma accumulated hydrogen peroxide and camalexin in leaves. When grown under axenic conditions, T. virens produced indole-3-carboxaldehyde (ICAld) a tryptophan-derived compound with activity in plant development. In Arabidopsis seedlings whose roots are in contact with T. virens or T. atroviride, and challenged with Botrytis cinerea in leaves, disease severity was significantly reduced compared to axenically grown seedlings. Our results indicate that the defense responses elicited by Trichoderma in Arabidopsis are complex and involve the canonical defense hormones SA and JA as well as camalexin, which may be important factors in boosting plant immunity.

  8. Transient Transcriptional Regulation of the CYS-C1 Gene and Cyanide Accumulation upon Pathogen Infection in the Plant Immune Response1[C][W

    PubMed Central

    García, Irene; Rosas, Tábata; Bejarano, Eduardo R.; Gotor, Cecilia; Romero, Luis C.

    2013-01-01

    Cyanide is produced concomitantly with ethylene biosynthesis. Arabidopsis (Arabidopsis thaliana) detoxifies cyanide primarily through the enzyme β-cyanoalanine synthase, mainly by the mitochondrial CYS-C1. CYS-C1 loss of function is not toxic for the plant and leads to an increased level of cyanide in cys-c1 mutants as well as a root hairless phenotype. The classification of genes differentially expressed in cys-c1 and wild-type plants reveals that the high endogenous cyanide content of the cys-c1 mutant is correlated with the biotic stress response. Cyanide accumulation and CYS-C1 gene expression are negatively correlated during compatible and incompatible plant-bacteria interactions. In addition, cys-c1 plants present an increased susceptibility to the necrotrophic fungus Botrytis cinerea and an increased tolerance to the biotrophic Pseudomonas syringae pv tomato DC3000 bacterium and Beet curly top virus. The cys-c1 mutation produces a reduction in respiration rate in leaves, an accumulation of reactive oxygen species, and an induction of the alternative oxidase AOX1a and pathogenesis-related PR1 expression. We hypothesize that cyanide, which is transiently accumulated during avirulent bacterial infection and constitutively accumulated in the cys-c1 mutant, uncouples the respiratory electron chain dependent on the cytochrome c oxidase, and this uncoupling induces the alternative oxidase activity and the accumulation of reactive oxygen species, which act by stimulating the salicylic acid-dependent signaling pathway of the plant immune system. PMID:23784464

  9. Transient transcriptional regulation of the CYS-C1 gene and cyanide accumulation upon pathogen infection in the plant immune response.

    PubMed

    García, Irene; Rosas, Tábata; Bejarano, Eduardo R; Gotor, Cecilia; Romero, Luis C

    2013-08-01

    Cyanide is produced concomitantly with ethylene biosynthesis. Arabidopsis (Arabidopsis thaliana) detoxifies cyanide primarily through the enzyme β-cyanoalanine synthase, mainly by the mitochondrial CYS-C1. CYS-C1 loss of function is not toxic for the plant and leads to an increased level of cyanide in cys-c1 mutants as well as a root hairless phenotype. The classification of genes differentially expressed in cys-c1 and wild-type plants reveals that the high endogenous cyanide content of the cys-c1 mutant is correlated with the biotic stress response. Cyanide accumulation and CYS-C1 gene expression are negatively correlated during compatible and incompatible plant-bacteria interactions. In addition, cys-c1 plants present an increased susceptibility to the necrotrophic fungus Botrytis cinerea and an increased tolerance to the biotrophic Pseudomonas syringae pv tomato DC3000 bacterium and Beet curly top virus. The cys-c1 mutation produces a reduction in respiration rate in leaves, an accumulation of reactive oxygen species, and an induction of the alternative oxidase AOX1a and pathogenesis-related PR1 expression. We hypothesize that cyanide, which is transiently accumulated during avirulent bacterial infection and constitutively accumulated in the cys-c1 mutant, uncouples the respiratory electron chain dependent on the cytochrome c oxidase, and this uncoupling induces the alternative oxidase activity and the accumulation of reactive oxygen species, which act by stimulating the salicylic acid-dependent signaling pathway of the plant immune system. PMID:23784464

  10. Immune response

    MedlinePlus

    ... cells. T cells are responsible for cell-mediated immunity. This type of immunity becomes deficient in persons with HIV, the virus ... blood. B lymphocytes provide the body with humoral immunity as they circulate in the fluids in search ...

  11. Immune Restoration

    MedlinePlus

    ... marrow cells immune to HIV infection. Letting the immune system repair itself: CD4 counts have increased for many ... have taken ART. Some scientists believe that the immune system might be able to heal and repair itself ...

  12. EDR1 Physically Interacts with MKK4/MKK5 and Negatively Regulates a MAP Kinase Cascade to Modulate Plant Innate Immunity

    PubMed Central

    Zhao, Chunzhao; Nie, Haozhen; Shen, Qiujing; Zhang, Shuqun; Lukowitz, Wolfgang; Tang, Dingzhong

    2014-01-01

    Mitogen-activated protein (MAP) kinase signaling cascades play important roles in the regulation of plant defense. The Raf-like MAP kinase kinase kinase (MAPKKK) EDR1 negatively regulates plant defense responses and cell death. However, how EDR1 functions, and whether it affects the regulation of MAPK cascades, are not well understood. Here, we showed that EDR1 negatively regulates the MKK4/MKK5-MPK3/MPK6 kinase cascade in Arabidopsis. We found that edr1 mutants have highly activated MPK3/MPK6 kinase activity and higher levels of MPK3/MPK6 proteins than wild type. EDR1 physically interacts with MKK4 and MKK5, and this interaction requires the N-terminal domain of EDR1. EDR1 also negatively affects MKK4/MKK5 protein levels. In addition, the mpk3, mkk4 and mkk5 mutations suppress edr1-mediated resistance, and over-expression of MKK4 or MKK5 causes edr1-like resistance and mildew-induced cell death. Taken together, our data indicate that EDR1 physically associates with MKK4/MKK5 and negatively regulates the MAPK cascade to fine-tune plant innate immunity. PMID:24830651

  13. Bacterial Cyclic β-(1,2)-Glucan Acts in Systemic Suppression of Plant Immune Responses[W

    PubMed Central

    Rigano, Luciano Ariel; Payette, Caroline; Brouillard, Geneviève; Marano, Maria Rosa; Abramowicz, Laura; Torres, Pablo Sebastián; Yun, Maximina; Castagnaro, Atilio Pedro; Oirdi, Mohamed El; Dufour, Vanessa; Malamud, Florencia; Dow, John Maxwell; Bouarab, Kamal; Vojnov, Adrian Alberto

    2007-01-01

    Although cyclic glucans have been shown to be important for a number of symbiotic and pathogenic bacterium–plant interactions, their precise roles are unclear. Here, we examined the role of cyclic β-(1,2)-glucan in the virulence of the black rot pathogen Xanthomonas campestris pv campestris (Xcc). Disruption of the Xcc nodule development B (ndvB) gene, which encodes a glycosyltransferase required for cyclic glucan synthesis, generated a mutant that failed to synthesize extracellular cyclic β-(1,2)-glucan and was compromised in virulence in the model plants Arabidopsis thaliana and Nicotiana benthamiana. Infection of the mutant bacterium in N. benthamiana was associated with enhanced callose deposition and earlier expression of the PATHOGENESIS-RELATED1 (PR-1) gene. Application of purified cyclic β-(1,2)-glucan prior to inoculation of the ndvB mutant suppressed the accumulation of callose deposition and the expression of PR-1 in N. benthamiana and restored virulence in both N. benthamiana and Arabidopsis plants. These effects were seen when cyclic glucan and bacteria were applied either to the same or to different leaves. Cyclic β-(1,2)-glucan–induced systemic suppression was associated with the transport of the molecule throughout the plant. Systemic suppression is a novel counterdefensive strategy that may facilitate pathogen spread in plants and may have important implications for the understanding of plant–pathogen coevolution and for the development of phytoprotection measures. PMID:17601826

  14. Colletotrichum higginsianum extracellular LysM proteins play dual roles in appressorial function and suppression of chitin-triggered plant immunity.

    PubMed

    Takahara, Hiroyuki; Hacquard, Stéphane; Kombrink, Anja; Hughes, H Bleddyn; Halder, Vivek; Robin, Guillaume P; Hiruma, Kei; Neumann, Ulla; Shinya, Tomonori; Kombrink, Erich; Shibuya, Naoto; Thomma, Bart P H J; O'Connell, Richard J

    2016-09-01

    The genome of the hemibiotrophic anthracnose fungus, Colletotrichum higginsianum, encodes a large repertoire of candidate-secreted effectors containing LysM domains, but the role of such proteins in the pathogenicity of any Colletotrichum species is unknown. Here, we characterized the function of two effectors, ChELP1 and ChELP2, which are transcriptionally activated during the initial intracellular biotrophic phase of infection. Using immunocytochemistry, we found that ChELP2 is concentrated on the surface of bulbous biotrophic hyphae at the interface with living host cells but is absent from filamentous necrotrophic hyphae. We show that recombinant ChELP1 and ChELP2 bind chitin and chitin oligomers in vitro with high affinity and specificity and that both proteins suppress the chitin-triggered activation of two immune-related plant mitogen-activated protein kinases in the host Arabidopsis. Using RNAi-mediated gene silencing, we found that ChELP1 and ChELP2 are essential for fungal virulence and appressorium-mediated penetration of both Arabidopsis epidermal cells and cellophane membranes in vitro. The findings suggest a dual role for these LysM proteins as effectors for suppressing chitin-triggered immunity and as proteins required for appressorium function. PMID:27174033

  15. Pseudomonas syringae type III effector HopAF1 suppresses plant immunity by targeting methionine recycling to block ethylene induction

    PubMed Central

    Washington, Erica J.; Mukhtar, M. Shahid; Finkel, Omri M.; Wan, Li; Kieber, Joseph J.; Dangl, Jeffery L.

    2016-01-01

    HopAF1 is a type III effector protein of unknown function encoded in the genomes of several strains of Pseudomonas syringae and other plant pathogens. Structural modeling predicted that HopAF1 is closely related to deamidase proteins. Deamidation is the irreversible substitution of an amide group with a carboxylate group. Several bacterial virulence factors are deamidases that manipulate the activity of specific host protein substrates. We identified Arabidopsis methylthioadenosine nucleosidase proteins MTN1 and MTN2 as putative targets of HopAF1 deamidation. MTNs are enzymes in the Yang cycle, which is essential for the high levels of ethylene biosynthesis in Arabidopsis. We hypothesized that HopAF1 inhibits the host defense response by manipulating MTN activity and consequently ethylene levels. We determined that bacterially delivered HopAF1 inhibits ethylene biosynthesis induced by pathogen-associated molecular patterns and that Arabidopsis mtn1 mtn2 mutant plants phenocopy the effect of HopAF1. Furthermore, we identified two conserved asparagines in MTN1 and MTN2 from Arabidopsis that confer loss of function phenotypes when deamidated via site-specific mutation. These residues are potential targets of HopAF1 deamidation. HopAF1-mediated manipulation of Yang cycle MTN proteins is likely an evolutionarily conserved mechanism whereby HopAF1 orthologs from multiple plant pathogens contribute to disease in a large variety of plant hosts. PMID:27274076

  16. Analysis of Globodera rostochiensis effectors reveals conserved functions of SPRYSEC proteins in suppressing and eliciting plant immune responses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Potato cyst nematodes (PCNs), including Globodera rostochiensis (Woll.), are important pests of potato. Plant parasitic nematodes produce multiple effector proteins, secreted from their stylets, to successfully infect their hosts. These include proteins that are delivered to the apoplast, as well as...

  17. Membrane-localized extra-large G proteins and Gbg of the heterotrimeric G proteins form functional complexes engaged in plant immunity in Arabidopsis.

    PubMed

    Maruta, Natsumi; Trusov, Yuri; Brenya, Eric; Parekh, Urvi; Botella, José Ramón

    2015-03-01

    In animals, heterotrimeric G proteins, comprising Ga, Gb, and Gg subunits, are molecular switches whose function tightly depends on Ga and Gbg interaction. Intriguingly, in Arabidopsis (Arabidopsis thaliana), multiple defense responses involve Gbg, but not Ga. We report here that the Gbg dimer directly partners with extra-large G proteins (XLGs) to mediate plant immunity. Arabidopsis mutants deficient in XLGs, Gb, and Gg are similarly compromised in several pathogen defense responses, including disease development and production of reactive oxygen species. Genetic analysis of double, triple, and quadruple mutants confirmed that XLGs and Gbg functionally interact in the same defense signaling pathways. In addition, mutations in XLG2 suppressed the seedling lethal and cell death phenotypes of BRASSINOSTEROID INSENSITIVE1-associated receptor kinase1-interacting receptor-like kinase1 mutants in an identical way as reported for Arabidopsis Gb-deficient mutants. Yeast (Saccharomyces cerevisiae) three-hybrid and bimolecular fluorescent complementation assays revealed that XLG2 physically interacts with all three possible Gbg dimers at the plasma membrane. Phylogenetic analysis indicated a close relationship between XLGs and plant Ga subunits, placing the divergence point at the dawn of land plant evolution. Based on these findings, we conclude that XLGs form functional complexes with Gbg dimers, although the mechanism of action of these complexes, including activation/deactivation, must be radically different form the one used by the canonical Ga subunit and are not likely to share the same receptors. Accordingly, XLGs expand the repertoire of heterotrimeric G proteins in plants and reveal a higher level of diversity in heterotrimeric G protein signaling.

  18. Membrane-Localized Extra-Large G Proteins and Gβγ of the Heterotrimeric G Proteins Form Functional Complexes Engaged in Plant Immunity in Arabidopsis1[OPEN

    PubMed Central

    Maruta, Natsumi; Trusov, Yuri; Brenya, Eric; Parekh, Urvi

    2015-01-01

    In animals, heterotrimeric G proteins, comprising Gα, Gβ, and Gγ subunits, are molecular switches whose function tightly depends on Gα and Gβγ interaction. Intriguingly, in Arabidopsis (Arabidopsis thaliana), multiple defense responses involve Gβγ, but not Gα. We report here that the Gβγ dimer directly partners with extra-large G proteins (XLGs) to mediate plant immunity. Arabidopsis mutants deficient in XLGs, Gβ, and Gγ are similarly compromised in several pathogen defense responses, including disease development and production of reactive oxygen species. Genetic analysis of double, triple, and quadruple mutants confirmed that XLGs and Gβγ functionally interact in the same defense signaling pathways. In addition, mutations in XLG2 suppressed the seedling lethal and cell death phenotypes of BRASSINOSTEROID INSENSITIVE1-associated receptor kinase1-interacting receptor-like kinase1 mutants in an identical way as reported for Arabidopsis Gβ-deficient mutants. Yeast (Saccharomyces cerevisiae) three-hybrid and bimolecular fluorescent complementation assays revealed that XLG2 physically interacts with all three possible Gβγ dimers at the plasma membrane. Phylogenetic analysis indicated a close relationship between XLGs and plant Gα subunits, placing the divergence point at the dawn of land plant evolution. Based on these findings, we conclude that XLGs form functional complexes with Gβγ dimers, although the mechanism of action of these complexes, including activation/deactivation, must be radically different form the one used by the canonical Gα subunit and are not likely to share the same receptors. Accordingly, XLGs expand the repertoire of heterotrimeric G proteins in plants and reveal a higher level of diversity in heterotrimeric G protein signaling. PMID:25588736

  19. Molecular steps in the immune signaling pathway evoked by plant elicitor peptides: Ca2+-dependent protein kinases, nitric oxide, and reactive oxygen species are downstream from the early Ca2+ signal.

    PubMed

    Ma, Yi; Zhao, Yichen; Walker, Robin K; Berkowitz, Gerald A

    2013-11-01

    Endogenous plant elicitor peptides (Peps) can act to facilitate immune signaling and pathogen defense responses. Binding of these peptides to the Arabidopsis (Arabidopsis thaliana) plasma membrane-localized Pep receptors (PEPRs) leads to cytosolic Ca(2+) elevation, an early event in a signaling cascade that activates immune responses. This immune response includes the amplification of signaling evoked by direct perception of pathogen-associated molecular patterns by plant cells under assault. Work included in this report further characterizes the Pep immune response and identifies new molecular steps in the signal transduction cascade. The PEPR coreceptor BRASSINOSTEROID-INSENSITIVE1 Associated Kinase1 contributes to generation of the Pep-activated Ca(2+) signal and leads to increased defense gene expression and resistance to a virulent bacterial pathogen. Ca(2+)-dependent protein kinases (CPKs) decode the Ca(2+) signal, also facilitating defense gene expression and enhanced resistance to the pathogen. Nitric oxide and reduced nicotinamide adenine dinucleotide phosphate oxidase-dependent reactive oxygen species generation (due to the function of Respiratory Burst Oxidase Homolog proteins D and F) are also involved downstream from the Ca(2+) signal in the Pep immune defense signal transduction cascade, as is the case with BRASSINOSTEROID-INSENSITIVE1 Associated Kinase1 and CPK5, CPK6, and CPK11. These steps of the pathogen defense response are required for maximal Pep immune activation that limits growth of a virulent bacterial pathogen in the plant. We find a synergism between function of the PEPR and Flagellin Sensing2 receptors in terms of both nitric oxide and reactive oxygen species generation. Presented results are also consistent with the involvement of the secondary messenger cyclic GMP and a cyclic GMP-activated Ca(2+)-conducting channel in the Pep immune signaling pathway.

  20. Eggplant and related species are promising genetic resources to dissect the plant immune response to Pseudomonas syringae and Xanthomonas euvesicatoria and to identify new resistance determinants.

    PubMed

    Clarke, Christopher R; Hayes, Byron W; Runde, Brendan J; Wicker, Emmanuel; Vinatzer, Boris A

    2014-10-01

    The apparent lack of durability of many resistance (R) genes highlights the need for the constant identification of new genetic sources of resistance for the breeding of new disease-resistant crop cultivars. To this end, we screened a collection of accessions of eggplant and close relatives for resistance against Pseudomonas syringae pv. tomato (Pto) and Xanthomonas euvesicatoria (Xeu), foliar plant pathogens of many solanaceous crops. Both pathogens caused substantial disease on most genotypes of eggplant and its relatives. Promisingly, however, some of the genotypes were fully or partially resistant to either of the pathogens, suggesting the presence of effective resistance determinants in these genotypes. Segregation of resistance to the growth of Xeu following infiltration in F2 progeny from a cross of a resistant and susceptible genotype suggests that resistance to Xeu is inherited as a multigenic trait. With regard to Pto, a mutant strain lacking all 28 functional type III secreted effectors, and a Pseudomonas fluorescens strain expressing a P. syringae type III secretion system (T3SS), both elicit a strong cell death response on most eggplant lines. Several genotypes thus appear to harbour a mechanism for the direct recognition of a component of the T3SS. Therefore, eggplant and its close relatives are promising resources to unravel novel aspects of plant immunity and to identify new candidate R genes that could be employed in other Solanaceae in which Xeu and Pto cause agriculturally relevant diseases.

  1. Integrated Immune

    NASA Technical Reports Server (NTRS)

    Crucian, Brian; Mehta, Satish; Stowe, Raymond; Uchakin, Peter; Quiriarte, Heather; Pierson, Duane; Sams, Clarnece

    2010-01-01

    This slide presentation reviews the program to replace several recent studies about astronaut immune systems with one comprehensive study that will include in-flight sampling. The study will address lack of in-flight data to determine the inflight status of immune systems, physiological stress, viral immunity, to determine the clinical risk related to immune dysregulation for exploration class spaceflight, and to determine the appropriate monitoring strategy for spaceflight-associated immune dysfunction, that could be used for the evaluation of countermeasures.

  2. The tomato NBARC-LRR protein Prf interacts with Pto kinase in vivo to regulate specific plant immunity.

    PubMed

    Mucyn, Tatiana S; Clemente, Alfonso; Andriotis, Vasilios M E; Balmuth, Alexi L; Oldroyd, Giles E D; Staskawicz, Brian J; Rathjen, John P

    2006-10-01

    Immunity in tomato (Solanum lycopersicum) to Pseudomonas syringae bacteria expressing the effector proteins AvrPto and AvrPtoB requires both Pto kinase and the NBARC-LRR (for nucleotide binding domain shared by Apaf-1, certain R gene products, and CED-4 fused to C-terminal leucine-rich repeats) protein Prf. Pto plays a direct role in effector recognition within the host cytoplasm, but the role of Prf is unknown. We show that Pto and Prf are coincident in the signal transduction pathway that controls ligand-independent signaling. Pto and Prf associate in a coregulatory interaction that requires Pto kinase activity and N-myristoylation for signaling. Pto interacts with a unique Prf N-terminal domain outside of the NBARC-LRR domain and resides in a high molecular weight recognition complex dependent on the presence of Prf. In this complex, both Pto and Prf contribute to specific recognition of AvrPtoB. The data suggest that the role of Pto is confined to the regulation of Prf and that the bacterial effectors have evolved to target this coregulatory molecular switch.

  3. Structure comparison of human glioma pathogenesis-related protein GliPR and the plant pathogenesis-related protein P14a indicates a functional link between the human immune system and a plant defense system.

    PubMed

    Szyperski, T; Fernández, C; Mumenthaler, C; Wüthrich, K

    1998-03-01

    The human glioma pathogenesis-related protein (GliPR) is highly expressed in the brain tumor glioblastoma multiforme and exhibits 35% amino acid sequence identity with the tomato pathogenesis-related (PR) protein P14a, which has an important role for the plant defense system. A molecular model of GliPR was computed with the distance geometry program DIANA on the basis of a P14a-GliPR sequence alignment and a set of 1,200 experimental NMR conformational constraints collected with P14a. The GliPR structure is represented by a group of 20 conformers with small residual DIANA target function values, low AMBER-energies after restrained energy-minimization with the program OPAL, and an average rms deviation relative to the mean of 1.6 A for the backbone heavy atoms. Comparison of the GliPR model with the P14a structure lead to the identification of a common partially solvent-exposed spatial cluster of four amino acid residues, His-69, Glu-88, Glu-110, and His-127 in the GliPR numeration. This cluster is conserved in all known plant PR proteins of class 1, indicating a common putative active site for GliPR and PR-1 proteins and thus a functional link between the human immune system and a plant defense system. PMID:9482873

  4. Structure comparison of human glioma pathogenesis-related protein GliPR and the plant pathogenesis-related protein P14a indicates a functional link between the human immune system and a plant defense system

    PubMed Central

    Szyperski, T.; Fernández, C.; Mumenthaler, C.; Wüthrich, K.

    1998-01-01

    The human glioma pathogenesis-related protein (GliPR) is highly expressed in the brain tumor glioblastoma multiforme and exhibits 35% amino acid sequence identity with the tomato pathogenesis-related (PR) protein P14a, which has an important role for the plant defense system. A molecular model of GliPR was computed with the distance geometry program diana on the basis of a P14a–GliPR sequence alignment and a set of 1,200 experimental NMR conformational constraints collected with P14a. The GliPR structure is represented by a group of 20 conformers with small residual diana target function values, low amber-energies after restrained energy-minimization with the program opal, and an average rms deviation relative to the mean of 1.6 Å for the backbone heavy atoms. Comparison of the GliPR model with the P14a structure lead to the identification of a common partially solvent-exposed spatial cluster of four amino acid residues, His-69, Glu-88, Glu-110, and His-127 in the GliPR numeration. This cluster is conserved in all known plant PR proteins of class 1, indicating a common putative active site for GliPR and PR-1 proteins and thus a functional link between the human immune system and a plant defense system. PMID:9482873

  5. Effect of host plant and immune challenge on the levels of chemosensory and odorant-binding proteins in caterpillar salivary glands.

    PubMed

    Celorio-Mancera, Maria de la Paz; Ytterberg, A Jimmy; Rutishauser, Dorothea; Janz, Niklas; Zubarev, Roman A

    2015-06-01

    More than half of the proteome from mandibular glands in caterpillars is represented by chemosensory proteins. Based on sequence similarity, these proteins are putative transporters of ligands to gustatory receptors in sensory organs of insects. We sought to determine whether these proteins are inducible by comparing, both qualitatively and quantitatively, the salivary (mandibular and labial) proteomes from caterpillars (Vanessa cardui) reared on different plants and artificial diet containing either bacteria or bacterial cell-walls. We included a treatment where the caterpillars were switched from feeding on artificial diet to plant material at some point in their development. Additionally, we evaluated the degree of overlap between the proteomes in the hemolymph-filled coelom and salivary glands of caterpillars reared on plant material. We found that the quality and quantity of the identified proteins differed clearly between hemolymph-filled coelome, labial and mandibular glands. Our results indicated that even after molting and two-day feeding on a new diet, protein production is affected by the previous food source used by the caterpillar. Candidate proteins involved in chemosensory perception by insects were detected: three chemosensory (CSPs) and two odorant-binding proteins (OBPs). Using the relative amounts of these proteins across tissues and treatments as criteria for their classification, we detected hemolymph- and mandibular gland-specific CSPs and observed that their levels were affected by caterpillar diet. Moreover, we could compare the protein and transcript levels across tissues and treatment for at least one CSP and one OBP. Therefore, we have identified specific isoforms for testing the role of CSPs and OBPs in plant and pathogen recognition. We detected catalase, immune-related protein and serine proteases and their inhibitors in high relative levels in the mandibular glands in comparison to the labial glands. These findings suggest that the

  6. Childhood Immunization

    MedlinePlus

    ... lowest levels in history, thanks to years of immunization. Children must get at least some vaccines before ... child provide protection for many years, adults need immunizations too. Centers for Disease Control and Prevention

  7. Immunizations - diabetes

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000331.htm Immunizations - diabetes To use the sharing features on this page, please enable JavaScript. Immunizations (vaccines or vaccinations) help protect you from some ...

  8. A plant-expressed conjugate vaccine breaks CD4+ tolerance and induces potent immunity against metastatic Her2+ breast cancer

    PubMed Central

    Chotprakaikiat, Warayut; Allen, Alex; Bui-Minh, Duc; Harden, Elena; Jobsri, Jantipa; Cavallo, Federica; Gleba, Yuri; Stevenson, Freda K.; Ottensmeier, Christian; Klimyuk, Victor; Savelyeva, Natalia

    2016-01-01

    ABSTRACT Passive antibody therapy for cancer is an effective but costly treatment modality. Induction of therapeutically potent anticancer antibodies by active vaccination is an attractive alternative but has proven challenging in cancer due to tolerogenic pressure in patients. Here, we used the clinically relevant cancer target Her2, known to be susceptible to targeting by antibody therapy, to demonstrate how potent antibody can be induced by vaccination. A novel 44kD Her2 protein fragment was generated and found to be highly effective at inducing anti-Her2 antibody including trastuzumab-like reactivities. In the tolerant and spontaneous BALB-neuT mouse model of metastatic breast cancer this Her2-targeting vaccine was only effective if the fragment was conjugated to a foreign immunogenic carrier; Fragment C of tetanus toxin. Only the conjugate vaccine induced high affinity anti-Her2 antibody of multiple isotypes and suppressed tumor development. The magnitude of CD4+ T-cell help and breadth of cytokines secreted by the CD4+ T helper (Th) cells induced to the foreign antigen was critical. We used a highly efficient plant-based bio-manufacturing process for protein antigens, magnICON, for vaccine expression, to underpin feasibility of future clinical testing. Hence, our novel Her2-targeting conjugate vaccine combines preclinical efficacy with clinical deliverability, thus setting the scene for therapeutic testing. PMID:27471642

  9. Analysis of a Plant Complex Resistance Gene Locus Underlying Immune-Related Hybrid Incompatibility and Its Occurrence in Nature

    PubMed Central

    Alcázar, Rubén; von Reth, Marcel; Bautor, Jaqueline; Chae, Eunyoung; Weigel, Detlef; Koornneef, Maarten; Parker, Jane E.

    2014-01-01

    Mechanisms underlying speciation in plants include detrimental (incompatible) genetic interactions between parental alleles that incur a fitness cost in hybrids. We reported on recessive hybrid incompatibility between an Arabidopsis thaliana strain from Poland, Landsberg erecta (Ler), and many Central Asian A. thaliana strains. The incompatible interaction is determined by a polymorphic cluster of Toll/interleukin-1 receptor-nucleotide binding-leucine rich repeat (TNL) RPP1 (Recognition of Peronospora parasitica1)-like genes in Ler and alleles of the receptor-like kinase Strubbelig Receptor Family 3 (SRF3) in Central Asian strains Kas-2 or Kond, causing temperature-dependent autoimmunity and loss of growth and reproductive fitness. Here, we genetically dissected the RPP1-like Ler locus to determine contributions of individual RPP1-like Ler (R1–R8) genes to the incompatibility. In a neutral background, expression of most RPP1-like Ler genes, except R3, has no effect on growth or pathogen resistance. Incompatibility involves increased R3 expression and engineered R3 overexpression in a neutral background induces dwarfism and sterility. However, no individual RPP1-like Ler gene is sufficient for incompatibility between Ler and Kas-2 or Kond, suggesting that co-action of at least two RPP1-like members underlies this epistatic interaction. We find that the RPP1-like Ler haplotype is frequent and occurs with other Ler RPP1-like alleles in a local population in Gorzów Wielkopolski (Poland). Only Gorzów individuals carrying the RPP1-like Ler haplotype are incompatible with Kas-2 and Kond, whereas other RPP1-like alleles in the population are compatible. Therefore, the RPP1-like Ler haplotype has been maintained in genetically different individuals at a single site, allowing exploration of forces shaping the evolution of RPP1-like genes at local and regional population scales. PMID:25503786

  10. Echinoderm immunity.

    PubMed

    Smith, L Courtney; Ghosh, Julie; Buckley, Katherine M; Clow, Lori A; Dheilly, Nolwenn M; Haug, Tor; Henson, John H; Li, Chun; Lun, Cheng Man; Majeske, Audrey J; Matranga, Valeria; Nair, Sham V; Rast, Jonathan P; Raftos, David A; Roth, Mattias; Sacchi, Sandro; Schrankel, Catherine S; Stensvåg, Klara

    2010-01-01

    A survey for immune genes in the genome for the purple sea urchin has shown that the immune system is complex and sophisticated. By inference, immune responses of all echinoderms maybe similar. The immune system is mediated by several types of coelomocytes that are also useful as sensors of environmental stresses. There are a number of large gene families in the purple sea urchin genome that function in immunity and of which at least one appears to employ novel approaches for sequence diversification. Echinoderms have a simpler complement system, a large set of lectin genes and a number of antimicrobial peptides. Profiling the immune genes expressed by coelomocytes and the proteins in the coelomic fluid provide detailed information about immune functions in the sea urchin. The importance of echinoderms in maintaining marine ecosystem stability and the disastrous effects of their removal due to disease will require future collaborations between ecologists and immunologists working towards understanding and preserving marine habitats. PMID:21528703

  11. [Mechanisms of innate immunity].

    PubMed

    Sochocka, Marta; Błach-Olszewska, Zofia

    2005-01-01

    Innate (natural) immunity differs from acquired immunity with respect to the detection systems (receptors and structures detected on pathogens), the cells engaged, and the nature of the mechanisms. Innate immunity is an ancient system, with similar structures in plants, invertebrates, and vertebrates are involved in the development of defense against pathogens. Toll-like receptor (TLR) structures are present in all organisms, and some mechanisms (i.e. complement activation) were also discovered in invertebrates and vertebrates. During infection, innate reactions develop before acquired immune reactions do. Natural immunity involves such reactions as the production of different cytokines, chemokines, and interleukins; the innate, cytokines-dependent nonspecific immunity of leukocytes; HLA-independent pathogen-killing cells, and phagocytosis. Such cytokines as interferons, the TNF family, and interleukines 12 and 18 participate in antiviral, antibacterial, antiprotozoan and anticancer natural immunity. NK cells, cytokines of the TNF family, and the complement system activated by lectins are engaged in the non-specific killing of infected or tumor cells. As over-activation of the innate system can be dangerous, the system must be submitted the strict control. The exact mechanism of this control system is not yet known, but there are several indications of its presence.

  12. Pepper Heat Shock Protein 70a Interacts with the Type III Effector AvrBsT and Triggers Plant Cell Death and Immunity1[OPEN

    PubMed Central

    Kim, Nak Hyun; Hwang, Byung Kook

    2015-01-01

    Heat shock proteins (HSPs) function as molecular chaperones and are essential for the maintenance and/or restoration of protein homeostasis. The genus Xanthomonas type III effector protein AvrBsT induces hypersensitive cell death in pepper (Capsicum annuum). Here, we report the identification of the pepper CaHSP70a as an AvrBsT-interacting protein. Bimolecular fluorescence complementation and coimmunoprecipitation assays confirm the specific interaction between CaHSP70a and AvrBsT in planta. The CaHSP70a peptide-binding domain is essential for its interaction with AvrBsT. Heat stress (37°C) and Xanthomonas campestris pv vesicatoria (Xcv) infection distinctly induce CaHSP70a in pepper leaves. Cytoplasmic CaHSP70a proteins significantly accumulate in pepper leaves to induce the hypersensitive cell death response by Xcv (avrBsT) infection. Transient CaHSP70a overexpression induces hypersensitive cell death under heat stress, which is accompanied by strong induction of defense- and cell death-related genes. The CaHSP70a peptide-binding domain and ATPase-binding domain are required to trigger cell death under heat stress. Transient coexpression of CaHSP70a and avrBsT leads to cytoplasmic localization of the CaHSP70a-AvrBsT complex and significantly enhances avrBsT-triggered cell death in Nicotiana benthamiana. CaHSP70a silencing in pepper enhances Xcv growth but disrupts the reactive oxygen species burst and cell death response during Xcv infection. Expression of some defense marker genes is significantly reduced in CaHSP70a-silenced leaves, with lower levels of the defense hormones salicylic acid and jasmonic acid. Together, these results suggest that CaHSP70a interacts with the type III effector AvrBsT and is required for cell death and immunity in plants. PMID:25491184

  13. Activation of Plant Immune Responses by a Gain-of-Function Mutation in an Atypical Receptor-Like Kinase1[C][W][OA

    PubMed Central

    Bi, Dongling; Cheng, Yu Ti; Li, Xin; Zhang, Yuelin

    2010-01-01

    Arabidopsis (Arabidopsis thaliana) suppressor of npr1-1, constitutive1 (snc1) contains a gain-of-function mutation in a Toll/interleukin receptor-nucleotide binding site-leucine-rich repeat Resistance (R) protein and it has been a useful tool for dissecting R-protein-mediated immunity. Here we report the identification and characterization of snc4-1D, a semidominant mutant with snc1-like phenotypes. snc4-1D constitutively expresses defense marker genes PR1, PR2, and PDF1.2, and displays enhanced pathogen resistance. Map-based cloning of SNC4 revealed that it encodes an atypical receptor-like kinase with two predicted extracellular glycerophosphoryl diester phosphodiesterase domains. The snc4-1D mutation changes an alanine to threonine in the predicted cytoplasmic kinase domain. Wild-type plants transformed with the mutant snc4-1D gene displayed similar phenotypes as snc4-1D, suggesting that the mutation is a gain-of-function mutation. Epistasis analysis showed that NON-RACE-SPECIFIC DISEASE RESISTANCE1 is required for the snc4-1D mutant phenotypes. In addition, the snc4-1D mutant phenotypes are partially suppressed by knocking out MAP KINASE SUBSTRATE1, a positive defense regulator associated with MAP KINASE4. Furthermore, both the morphology and constitutive pathogen resistance of snc4-1D are partially suppressed by blocking jasmonic acid synthesis, suggesting that jasmonic acid plays an important role in snc4-1D-mediated resistance. Identification of snc4-1D provides us a unique genetic system for analyzing the signal transduction pathways downstream of receptor-like kinases. PMID:20508139

  14. Quercetin, Inflammation and Immunity

    PubMed Central

    Li, Yao; Yao, Jiaying; Han, Chunyan; Yang, Jiaxin; Chaudhry, Maria Tabassum; Wang, Shengnan; Liu, Hongnan; Yin, Yulong

    2016-01-01

    In vitro and some animal models have shown that quercetin, a polyphenol derived from plants, has a wide range of biological actions including anti-carcinogenic, anti-inflammatory and antiviral activities; as well as attenuating lipid peroxidation, platelet aggregation and capillary permeability. This review focuses on the physicochemical properties, dietary sources, absorption, bioavailability and metabolism of quercetin, especially main effects of quercetin on inflammation and immune function. According to the results obtained both in vitro and in vivo, good perspectives have been opened for quercetin. Nevertheless, further studies are needed to better characterize the mechanisms of action underlying the beneficial effects of quercetin on inflammation and immunity. PMID:26999194

  15. Quercetin, Inflammation and Immunity.

    PubMed

    Li, Yao; Yao, Jiaying; Han, Chunyan; Yang, Jiaxin; Chaudhry, Maria Tabassum; Wang, Shengnan; Liu, Hongnan; Yin, Yulong

    2016-03-01

    In vitro and some animal models have shown that quercetin, a polyphenol derived from plants, has a wide range of biological actions including anti-carcinogenic, anti-inflammatory and antiviral activities; as well as attenuating lipid peroxidation, platelet aggregation and capillary permeability. This review focuses on the physicochemical properties, dietary sources, absorption, bioavailability and metabolism of quercetin, especially main effects of quercetin on inflammation and immune function. According to the results obtained both in vitro and in vivo, good perspectives have been opened for quercetin. Nevertheless, further studies are needed to better characterize the mechanisms of action underlying the beneficial effects of quercetin on inflammation and immunity. PMID:26999194

  16. Immune System

    EPA Science Inventory

    A properly functioning immune system is essential to good health. It defends the body against infectious agents and in some cases tumor cells. Individuals with immune deficiencies resulting from genetic defects, diseases (e.g., AIDS, leukemia), or drug therapies are more suscepti...

  17. Maternal immunization

    PubMed Central

    Moniz, Michelle H; Beigi, Richard H

    2014-01-01

    Maternal immunization holds tremendous promise to improve maternal and neonatal health for a number of infectious conditions. The unique susceptibilities of pregnant women to infectious conditions, as well as the ability of maternally-derived antibody to offer vital neonatal protection (via placental transfer), together have produced the recent increased attention on maternal immunization. The Advisory Committee on Immunization Practices (ACIP) currently recommends 2 immunizations for all pregnant women lacking contraindication, inactivated Influenza and tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap). Given ongoing research the number of vaccines recommended during pregnancy is likely to increase. Thus, achieving high vaccination coverage of pregnant women for all recommended immunizations is a key public health enterprise. This review will focus on the present state of vaccine acceptance in pregnancy, with attention to currently identified barriers and determinants of vaccine acceptance. Additionally, opportunities for improvement will be considered. PMID:25483490

  18. Immunization Coverage

    MedlinePlus

    ... underused vaccines is increasing. Immunization currently averts an estimated 2 to 3 million deaths every year. An ... avoided, however, if global vaccination coverage improves. An estimated 19.4 million infants worldwide are still missing ...

  19. Adolescent immunization.

    PubMed

    Handal, G A

    2000-06-01

    The dramatic improvements achieved in the control of vaccine-preventable diseases in children have only been shared partially by adolescents and young adults, as today several million adolescents are not receiving the full complement of vaccines recommended by the Advisory Committee on Immunization Practices (ACIP). This article discusses the reasons for this problem and the tools to bridge this gap. In particular, medical societies and the Centers for Disease Control and Prevention (CDC) recommend a close assessment of the adolescentís immunization status between 11 and 12 years of age, inclusion of school immunization, and providing missing immunizations at any opportunity. The article also addresses other vaccines recommended for groups of adolescents with special needs, reporting information, and provides an update on the vaccines of the future.

  20. Immune-system-dependent anti-tumor activity of a plant-derived polyphenol rich fraction in a melanoma mouse model.

    PubMed

    Gomez-Cadena, A; Urueña, C; Prieto, K; Martinez-Usatorre, A; Donda, A; Barreto, A; Romero, P; Fiorentino, S

    2016-06-02

    Recent findings suggest that part of the anti-tumor effects of several chemotherapeutic agents require an intact immune system. This is in part due to the induction of immunogenic cell death. We have identified a gallotannin-rich fraction, obtained from Caesalpinia spinosa (P2Et) as an anti-tumor agent in both breast carcinoma and melanoma. Here, we report that P2Et treatment results in activation of caspase 3 and 9, mobilization of cytochrome c and externalization of annexin V in tumor cells, thus suggesting the induction of apoptosis. This was preceded by the onset of autophagy and the expression of immunogenic cell death markers. We further demonstrate that P2Et-treated tumor cells are highly immunogenic in vaccinated mice and induce immune system activation, clearly shown by the generation of interferon gamma (IFN-γ) producing tyrosine-related protein 2 antigen-specific CD8+ T cells. Moreover, the tumor protective effects of P2Et treatment were abolished in immunodeficient mice, and partially lost after CD4 and CD8 depletion, indicating that P2Et's anti-tumor activity is highly dependent on immune system and at least in part of T cells. Altogether, these results support the hypothesis that the gallotannin-rich fraction P2Et's anti-tumor effects are mediated to a great extent by the endogenous immune response following to the exposure to immunogenic dying tumor cells.

  1. Adult immunization

    PubMed Central

    Mehta, Bharti; Chawla, Sumit; Kumar Dharma, Vijay; Jindal, Harashish; Bhatt, Bhumika

    2014-01-01

    Vaccination is recommended throughout life to prevent vaccine-preventable diseases and their sequel. The primary focus of vaccination programs has historically been directed to childhood immunizations. For adults, chronic diseases have been the primary focus of preventive and medical health care, though there has been increased emphasis on preventing infectious diseases. Adult vaccination coverage, however, remains low for most of the routinely recommended vaccines. Though adults are less susceptible to fall prey to traditional infectious agents, the probability of exposure to infectious agents has increased manifold owing to globalization and increasing travel opportunities both within and across the countries. Thus, there is an urgent need to address the problem of adult immunization. The adult immunization enterprise is more complex, encompassing a wide variety of vaccines and a very diverse target population. There is no coordinated public health infrastructure to support an adult immunization program as there is for children. Moreover, there is little coordination among adult healthcare providers in terms of vaccine provision. Substantial improvement in adult vaccination is needed to reduce the health consequences of vaccine-preventable diseases among adults. Routine assessment of adult patient vaccination needs, recommendation, and offer of needed vaccines for adults should be incorporated into routine clinical care of adults. PMID:24128707

  2. The bacterial lipopeptide iturins induce Verticillium dahliae cell death by affecting fungal signalling pathways and mediate plant defence responses involved in pathogen-associated molecular pattern-triggered immunity.

    PubMed

    Han, Qin; Wu, Fengli; Wang, Xiaonan; Qi, Hong; Shi, Liang; Ren, Ang; Liu, Qinghai; Zhao, Mingwen; Tang, Canming

    2015-04-01

    Verticillium wilt in cotton caused by Verticillium dahliae is one of the most serious plant diseases worldwide. Because no known fungicides or cotton cultivars provide sufficient protection against this pathogen, V. dahliae causes major crop yield losses. Here, an isolated cotton endophytic bacterium, designated Bacillus amyloliquefaciens 41B-1, exhibited greater than 50% biocontrol efficacy against V. dahliae in cotton plants under greenhouse conditions. Through high-performance liquid chromatography and mass analysis of the filtrate, we found that the antifungal compounds present in the strain 41B-1 culture filtrate were a series of isoforms of iturins. The purified iturins suppressed V. dahliae microsclerotial germination in the absence or presence of cotton. Treatment with the iturins induced reactive oxygen species bursts, Hog1 mitogen-activated protein kinase (MAPK) activation and defects in cell wall integrity. The oxidative stress response and high-osmolarity glycerol pathway contribute to iturins resistance in V. dahliae. In contrast, the Slt2 MAPK pathway may be involved in iturins sensitivity in this fungus. In addition to antagonism, iturins could induce plant defence responses as activators and mediate pathogen-associated molecular pattern-triggered immunity. These findings suggest that iturins may affect fungal signalling pathways and mediate plant defence responses against V. dahliae.

  3. Making healthier or killing enemies? Bacterial volatile-elicited plant immunity plays major role upon protection of Arabidopsis than the direct pathogen inhibition

    PubMed Central

    Sharifi, Rouhallah; Ryu, Choong-Min

    2016-01-01

    ABSTRACT Bacterial volatiles protect plants either by directly inhibiting a pathogenic fungus or by improving the defense capabilities of plants. The effect of bacterial volatiles on fungal growth was dose-dependent. A low dosage did not have a noticeable effect on Botrytis cinerea growth and development, but was sufficient to elicit induced resistance in Arabidopsis thaliana. Bacterial volatiles displayed negative effects on biofilm formation on a polystyrene surface and in in planta leaf colonization of B. cinerea. However, bacterial volatile-mediated induced resistance was the major mechanism mediating protection of plants from B. cinerea. It was responsible for more than 90% of plant protection in comparison with direct fungal inhibition. Our results broaden our knowledge of the role of bacterial volatiles in plant protection. PMID:27574539

  4. Making healthier or killing enemies? Bacterial volatile-elicited plant immunity plays major role upon protection of Arabidopsis than the direct pathogen inhibition.

    PubMed

    Sharifi, Rouhallah; Ryu, Choong-Min

    2016-01-01

    Bacterial volatiles protect plants either by directly inhibiting a pathogenic fungus or by improving the defense capabilities of plants. The effect of bacterial volatiles on fungal growth was dose-dependent. A low dosage did not have a noticeable effect on Botrytis cinerea growth and development, but was sufficient to elicit induced resistance in Arabidopsis thaliana. Bacterial volatiles displayed negative effects on biofilm formation on a polystyrene surface and in in planta leaf colonization of B. cinerea. However, bacterial volatile-mediated induced resistance was the major mechanism mediating protection of plants from B. cinerea. It was responsible for more than 90% of plant protection in comparison with direct fungal inhibition. Our results broaden our knowledge of the role of bacterial volatiles in plant protection. PMID:27574539

  5. Making healthier or killing enemies? Bacterial volatile-elicited plant immunity plays major role upon protection of Arabidopsis than the direct pathogen inhibition.

    PubMed

    Sharifi, Rouhallah; Ryu, Choong-Min

    2016-01-01

    Bacterial volatiles protect plants either by directly inhibiting a pathogenic fungus or by improving the defense capabilities of plants. The effect of bacterial volatiles on fungal growth was dose-dependent. A low dosage did not have a noticeable effect on Botrytis cinerea growth and development, but was sufficient to elicit induced resistance in Arabidopsis thaliana. Bacterial volatiles displayed negative effects on biofilm formation on a polystyrene surface and in in planta leaf colonization of B. cinerea. However, bacterial volatile-mediated induced resistance was the major mechanism mediating protection of plants from B. cinerea. It was responsible for more than 90% of plant protection in comparison with direct fungal inhibition. Our results broaden our knowledge of the role of bacterial volatiles in plant protection.

  6. Trained immunity: A smart way to enhance innate immune defence.

    PubMed

    van der Meer, Jos W M; Joosten, Leo A B; Riksen, Niels; Netea, Mihai G

    2015-11-01

    The innate arm of the immune system is generally viewed as primitive and non-specific and - in contrast to the adaptive immune arm - not to possess memory. However in plants and invertebrate animals that lack adaptive immunity, innate immunity will exhibit a prolonged enhanced functional state after adequate priming. A similar enhancement of function of the innate immunity has occasionally been described in vertebrates, including humans. Over the past few years we have studied this phenomenon in greater detail and we have coined the term 'Trained (innate) immunity' (TI). TI can be induced by a variety of stimuli, of which we have studied BCG and β-glucan in greater detail. The non-specific protective effects of BCG that have been observed in vaccination studies in the literature are probably due to TI. Monocytes and macrophages are among the main cells of the innate immune arm that can be trained. We have discovered that both BCG (via NOD2 signalling) and β-glucan (via dectin-1) induce epigenetic reprogramming, in particular stable changes in histone trimethylation at H3K4. These epigenetic changes lead to cellular activation, enhanced cytokine production and a change in the metabolic state of the cell with a shift from oxidative phosphorylation to aerobic glycolysis. TI is not only important for host defence and vaccine responses, but most probably also for diseases like atherosclerosis. Modulation of TI is a promising area for new treatments.

  7. Immunization Schedules for Adults

    MedlinePlus

    ... ACIP Vaccination Recommendations Why Immunize? Vaccines: The Basics Immunization Schedules for Adults in Easy-to-read Formats ... previous immunizations. View or Print a Schedule Recommended Immunizations for Adults (19 Years and Older) by Age ...

  8. miRNA863-3p sequentially targets negative regulators—atypical receptor-like Pseudokinases—and serrate, a positive regulator of plant immunity upon infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant small RNAs (sRNAs) play important roles in regulating gene expression during pathogen infection. We identified miR863-3p, which is specifically induced by the avirulent bacterial pathogen Pseudomonas syringae pv. tomato DC3000 carrying the effector avrRpt2. During early infection stages, miR86...

  9. Mushroom plant workers experience a shift towards a T helper type 2 dominant state: contribution of innate immunity to spore antigen

    PubMed Central

    SAIKAI, T; TANAKA, H; SATO, N; ABE, S; MATSUURA, A

    2004-01-01

    Contemporary mushroom factories are places where there is a substantial risk of the occurrence of respiratory allergy. The aims of this investigation were to estimate its causative agents and to evaluate the contribution of innate immune response in mushroom workers who cultivate Hypsizigus marmoreus (Bunashimeji). Cross-sectional and follow-up studies were performed in the factory. We investigated CD1b, CD3, CD4, CD8, CD14, CD45RO, CD62L and CD161 expression in peripheral blood mononuclear cells (PBMC) by flow cytometry, and serum levels of interleukin (IL-2), IL-4, granulocyte-macrophage colony stimulating factor (GM-CSF), IL-13 and interferon (IFN)-γ by enzyme-linked immunosorbent assay (ELISA). Co-culture experiments of PBMC with spore extracts were also performed. Percentages of CD1b+ monocytes, natural killer (NK), NK T and CD4+ T cells were increased in the workers compared with controls. Increases in Th2 type cells, Th2/Th1 ratio and serum IL-13 and decreased IFN-γ were detected, indicating a Th2-biased status of the workers. The follow-up study showed that monocytes and NK cells increased soon after employment while CD4+ T, Th2 and NK T cells increased gradually as employment time lengthened. Serum precipitating antibody to the mushroom antigen could be detected at a later stage. Co-cultivation of PBMC with the spore extracts induced much higher CD1b expression, and suppressed secretion of Th1 cytokine in culture supernatants. These results indicate that the mushroom antigen contains highly immunogenic substances which stimulate PBMC into a Th2-biased in vivo status, and innate immune cells might also play a critical role in developing respiratory allergy in mushroom workers. PMID:14678272

  10. Mushroom plant workers experience a shift towards a T helper type 2 dominant state: contribution of innate immunity to spore antigen.

    PubMed

    Saikai, T; Tanaka, H; Sato, N; Abe, S; Matsuura, A

    2004-01-01

    Contemporary mushroom factories are places where there is a substantial risk of the occurrence of respiratory allergy. The aims of this investigation were to estimate its causative agents and to evaluate the contribution of innate immune response in mushroom workers who cultivate Hypsizigus marmoreus (Bunashimeji). Cross-sectional and follow-up studies were performed in the factory. We investigated CD1b, CD3, CD4, CD8, CD14, CD45RO, CD62L and CD161 expression in peripheral blood mononuclear cells (PBMC) by flow cytometry, and serum levels of interleukin (IL-2), IL-4, granulocyte-macrophage colony stimulating factor (GM-CSF), IL-13 and interferon (IFN)-gamma by enzyme-linked immunosorbent assay (ELISA). Co-culture experiments of PBMC with spore extracts were also performed. Percentages of CD1b+ monocytes, natural killer (NK), NK T and CD4+ T cells were increased in the workers compared with controls. Increases in Th2 type cells, Th2/Th1 ratio and serum IL-13 and decreased IFN-gamma were detected, indicating a Th2-biased status of the workers. The follow-up study showed that monocytes and NK cells increased soon after employment while CD4+ T, Th2 and NK T cells increased gradually as employment time lengthened. Serum precipitating antibody to the mushroom antigen could be detected at a later stage. Co-cultivation of PBMC with the spore extracts induced much higher CD1b expression, and suppressed secretion of Th1 cytokine in culture supernatants. These results indicate that the mushroom antigen contains highly immunogenic substances which stimulate PBMC into a Th2-biased in vivo status, and innate immune cells might also play a critical role in developing respiratory allergy in mushroom workers.

  11. Integrated Circuit Immunity

    NASA Technical Reports Server (NTRS)

    Sketoe, J. G.; Clark, Anthony

    2000-01-01

    This paper presents a DOD E3 program overview on integrated circuit immunity. The topics include: 1) EMI Immunity Testing; 2) Threshold Definition; 3) Bias Tee Function; 4) Bias Tee Calibration Set-Up; 5) EDM Test Figure; 6) EMI Immunity Levels; 7) NAND vs. and Gate Immunity; 8) TTL vs. LS Immunity Levels; 9) TP vs. OC Immunity Levels; 10) 7805 Volt Reg Immunity; and 11) Seventies Chip Set. This paper is presented in viewgraph form.

  12. [Plant hormones, plant growth regulators].

    PubMed

    Végvári, György; Vidéki, Edina

    2014-06-29

    Plants seem to be rather defenceless, they are unable to do motion, have no nervous system or immune system unlike animals. Besides this, plants do have hormones, though these substances are produced not in glands. In view of their complexity they lagged behind animals, however, plant organisms show large scale integration in their structure and function. In higher plants, such as in animals, the intercellular communication is fulfilled through chemical messengers. These specific compounds in plants are called phytohormones, or in a wide sense, bioregulators. Even a small quantity of these endogenous organic compounds are able to regulate the operation, growth and development of higher plants, and keep the connection between cells, tissues and synergy between organs. Since they do not have nervous and immume systems, phytohormones play essential role in plants' life.

  13. [Plant hormones, plant growth regulators].

    PubMed

    Végvári, György; Vidéki, Edina

    2014-06-29

    Plants seem to be rather defenceless, they are unable to do motion, have no nervous system or immune system unlike animals. Besides this, plants do have hormones, though these substances are produced not in glands. In view of their complexity they lagged behind animals, however, plant organisms show large scale integration in their structure and function. In higher plants, such as in animals, the intercellular communication is fulfilled through chemical messengers. These specific compounds in plants are called phytohormones, or in a wide sense, bioregulators. Even a small quantity of these endogenous organic compounds are able to regulate the operation, growth and development of higher plants, and keep the connection between cells, tissues and synergy between organs. Since they do not have nervous and immume systems, phytohormones play essential role in plants' life. PMID:24954142

  14. Bacterial RNAs activate innate immunity in Arabidopsis.

    PubMed

    Lee, Boyoung; Park, Yong-Soon; Lee, Soohyun; Song, Geun Cheol; Ryu, Choong-Min

    2016-01-01

    The common molecular patterns of microbes play a critical role in the regulation of plant innate immunity. However, little is known about the role of nucleic acids in this process in plants. We pre-infiltrated Arabidopsis leaves with total RNAs from Pseudomonas syringae pv. tomato DC3000 (Pto DC3000) and subsequently inoculated these plants with the same bacterial cells. Total Pto DC3000 RNAs pre-infiltrated into Arabidopsis leaves elicited plant immune responses against Pto DC3000. However, sheared RNAs and RNase A application failed to induce immunity, suggesting that intact bacterial RNAs function in plant innate immunity. This notion was supported by the positive regulation of superoxide anion levels, callose deposition, two mitogen-activated protein kinases and defense-related genes observed in bacterial RNA-pre-treated leaves. Intriguingly, the Pto DC3000 population was not compromised in known pattern recognition receptor mutants for chitin, flagellin and elongation factor-Tu (EF-Tu). Plant defense-related mutant analyses further revealed that bacterial RNA-elicited innate immunity was normally required for salicylic and jasmonic acid signaling. Notably, among total RNAs, the abundant bacterial RNA species 16S and 23S ribosomal RNAs were the major determinants of this response. Our findings provide evidence that bacterial RNA serves as a microbe-associated molecular pattern in plants. PMID:26499893

  15. Immunity and immunization in elderly.

    PubMed

    Bourée, Patrice

    2003-12-01

    As the average life expectancy increases, retired people want to travel. Five to 8% of travellers in tropical areas are old persons. Immune system suffers of old age as the other organs. The number and the functions of the T-lymphocytes decrease, but the B-lymphocytes are not altered. So, the response to the vaccinations is slower and lower in the elderly. Influenza is a great cause of death rate in old people. The seroconversion, after vaccine, is 50% from 60 to 70 years old, 31% from 70 to 80 years old, and only 11% after 80 years old. But in public health, the vaccination reduced the morbidity by 25%, admission to hospital by 20%, pneumonia by 50%, and mortality by 70%. Antipoliomyelitis vaccine is useful for travellers, as the vaccines against hepatitis and typhoid fever. Pneumococcal vaccine is effective in 60%. Tetanus is fatal in at last 32% of the people above 80 years, therefore this vaccine is very important.

  16. Immune System Involvement

    MedlinePlus

    ... Tips" to find out more! Email * Zipcode The Immune System and Psoriatic Disease What is an autoimmune disease? ... swollen and painful joints and tendons. Treating the immune system The immune system is not only the key ...

  17. Immunization and Pregnancy

    MedlinePlus

    Immunization & Pregnancy Vaccines help keep apregnant woman and her growing family healthy. Vaccine Before pregnancy Hepatitis A ... 232-4636) • English or Spanish National Center for Immunization and Respiratory Diseases Immunization Services Division CS238938B 03/ ...

  18. Childhood Immunization Schedule

    MedlinePlus

    ... Recommendations Why Immunize? Vaccines: The Basics Instant Childhood Immunization Schedule Recommend on Facebook Tweet Share Compartir Get ... date. See Disclaimer for additional details. Based on Immunization Schedule for Children 0 through 6 Years of ...

  19. Our Immune System

    MedlinePlus

    Our Immune System A story for children with primary immunodeficiency diseases Written by Sara LeBien IMMUNE DEFICIENCY FOUNDATION A note ... who are immune deficient to better understand their immune system. What is a “ B-cell, ” a “ T-cell, ” ...

  20. Immunization for Women

    MedlinePlus

    ... nfid.org/#sthash.eZ72dCSP.dpuf Diseases & Vaccines Overview Immunization Schedules Talk to you doctor about your immunization ... years Immunization Schedule for Children, 7-18 years Immunization News July 8, 2016 HPV-related cancers on ...

  1. Your Child's Immunizations

    MedlinePlus

    ... Things to Know About Zika & Pregnancy Your Child's Immunizations KidsHealth > For Parents > Your Child's Immunizations Print A A A Text Size What's in ... But in both cases, the protection is temporary. Immunization (vaccination) is a way of creating immunity to ...

  2. Understanding Herd Immunity.

    PubMed

    Metcalf, C J E; Ferrari, M; Graham, A L; Grenfell, B T

    2015-12-01

    Individual immunity is a powerful force affecting host health and pathogen evolution. Importantly, the effects of individual immunity also scale up to affect pathogen transmission dynamics and the success of vaccination campaigns for entire host populations. Population-scale immunity is often termed 'herd immunity'. Here we outline how individual immunity maps to population outcomes and discuss implications for control of infectious diseases. Particular immunological characteristics may be more or less likely to result in a population level signature of herd immunity; we detail this and also discuss other population-level outcomes that might emerge from individual-level immunity.

  3. Integrated Immune Experiment

    NASA Technical Reports Server (NTRS)

    Crucian, Brian

    2009-01-01

    This viewgraph presentation reviews NASA's Integrated Immune Experiment. The objectives include: 1) Address significant lack of data regarding immune status during flight; 2) Replace several recent immune studies with one comprehensive study that will include in-flight sampling; 3) Determine the in-flight status of immunity, physiological stress, viral immunity/reactivation; 4) Determine the clinical risk related to immune dysregulation for exploration class spaceflight; and 5) Determine the appropriate monitoring strategy for spaceflight-associated immune dysfunction, that could be used for the evaluation of countermeasures.

  4. Immune Suppression and Immune Activation in Depression

    PubMed Central

    Blume, Joshua; Douglas, Steven D.; Evans, Dwight L.

    2010-01-01

    Depression has been characterized as a disorder of both immune suppression and immune activation. Markers of impaired cellular immunity (decreased natural killer cell cytotoxicity) and inflammation (elevated IL-6, TNFα, CRP) have been associated with depression. These immunological markers have been associated with other medical illnesses, suggesting that immune dysregulation may be a central feature common to both depression and to its frequent medical comorbidities. Yet the significant associations of findings of both immune suppression and immune activation with depression raise questions concerning the relationship between these two classes of immunological observations. Depressed populations are heterogeneous groups, and there may be differences in the immune profiles of populations that are more narrowly defined in terms of symptom profile and/or demographic features. There have been few reports concurrently investigating markers of immune suppression and immune activation in the same depressed individuals. An emerging preclinical literature suggests that chronic inflammation may directly contribute to the pathophysiology of immune suppression in the context of illnesses such as cancer and rheumatoid arthritis. This literature provides us with specific immunoregulatory mechanisms mediating these relationships that could also explain differences in immune disturbances between subsets of depressed individuals We propose a research agenda emphasizing the assessment of these immunoregulatory mechanisms in large samples of depressed subjects as a means to define the relationships among immune findings (suppression and/or activation) within the same depressed individuals and to characterize subsets of depressed subjects based on shared immune profiles. Such a program of research, building on and integrating our knowledge of the psychoneuroimmunology of depression, could lead to innovation in the assessment and treatment of depression and its medical comorbidities

  5. Theoretical aspects of immunity.

    PubMed

    Deem, Michael W; Hejazi, Pooya

    2010-01-01

    The immune system recognizes a myriad of invading pathogens and their toxic products. It does so with a finite repertoire of antibodies and T cell receptors. We here describe theories that quantify the dynamics of the immune system. We describe how the immune system recognizes antigens by searching the large space of receptor molecules. We consider in some detail the theories that quantify the immune response to influenza and dengue fever. We review theoretical descriptions of the complementary evolution of pathogens that occurs in response to immune system pressure. Methods including bioinformatics, molecular simulation, random energy models, and quantum field theory contribute to a theoretical understanding of aspects of immunity.

  6. Imbalanced immune homeostasis in immune thrombocytopenia.

    PubMed

    Yazdanbakhsh, Karina

    2016-04-01

    Immune thrombocytopenia (ITP) is an autoimmune bleeding disorder resulting from low platelet counts caused by inadequate production as well as increased destruction by autoimmune mechanisms. As with other autoimmune disorders, chronic ITP is characterized by perturbations of immune homeostasis with hyperactivated effector cells as well as defective regulatory arm of the adaptive immune system, which will be reviewed here. Interestingly, some ITP treatments are associated with restoring the regulatory imbalance, although it remains unclear whether the immune system is redirected to a state of tolerance once treatment is discontinued. Understanding the mechanisms that result in breakdown of immune homeostasis in ITP will help to identify novel pathways for restoring tolerance and inhibiting effector cell responses. This information can then be translated into developing therapies for averting autoimmunity not only in ITP but also many autoimmune disorders. PMID:27312156

  7. Imbalanced immune homeostasis in immune thrombocytopenia.

    PubMed

    Yazdanbakhsh, Karina

    2016-04-01

    Immune thrombocytopenia (ITP) is an autoimmune bleeding disorder resulting from low platelet counts caused by inadequate production as well as increased destruction by autoimmune mechanisms. As with other autoimmune disorders, chronic ITP is characterized by perturbations of immune homeostasis with hyperactivated effector cells as well as defective regulatory arm of the adaptive immune system, which will be reviewed here. Interestingly, some ITP treatments are associated with restoring the regulatory imbalance, although it remains unclear whether the immune system is redirected to a state of tolerance once treatment is discontinued. Understanding the mechanisms that result in breakdown of immune homeostasis in ITP will help to identify novel pathways for restoring tolerance and inhibiting effector cell responses. This information can then be translated into developing therapies for averting autoimmunity not only in ITP but also many autoimmune disorders.

  8. Immunity by equilibrium.

    PubMed

    Eberl, Gérard

    2016-08-01

    The classical model of immunity posits that the immune system reacts to pathogens and injury and restores homeostasis. Indeed, a century of research has uncovered the means and mechanisms by which the immune system recognizes danger and regulates its own activity. However, this classical model does not fully explain complex phenomena, such as tolerance, allergy, the increased prevalence of inflammatory pathologies in industrialized nations and immunity to multiple infections. In this Essay, I propose a model of immunity that is based on equilibrium, in which the healthy immune system is always active and in a state of dynamic equilibrium between antagonistic types of response. This equilibrium is regulated both by the internal milieu and by the microbial environment. As a result, alteration of the internal milieu or microbial environment leads to immune disequilibrium, which determines tolerance, protective immunity and inflammatory pathology.

  9. Immune Responses in Neonates

    PubMed Central

    Basha, Saleem; Surendran, Naveen; Pichichero, Michael

    2015-01-01

    Neonates have little immunological memory and a developing immune system, which increases their vulnerability to infectious agents. Recent advances in understanding of neonatal immunity indicate that both innate and adaptive responses are dependent on precursor frequency of lymphocytes, antigenic dose and mode of exposure. Studies in neonatal mouse models and human umbilical cord blood cells demonstrate the capability of neonatal immune cells to produce immune responses similar to adults in some aspects but not others. This review focuses mainly on the developmental and functional mechanisms of the human neonatal immune system. In particular, the mechanism of innate and adaptive immunity and the role of neutrophils, antigen presenting cells, differences in subclasses of T lymphocytes (Th1, Th2, Tregs) and B cells are discussed. In addition, we have included the recent developments in neonatal mouse immune system. Understanding neonatal immunity is essential to development of therapeutic vaccines to combat newly emerging infectious agents. PMID:25088080

  10. Immunity to cancer

    SciTech Connect

    Reif, A.E.; Mitchell, M.S.

    1985-01-01

    This book contains five sections, each containing several papers. The section titles are: Identification and Characterization of Tumor Antigens; Immune Responses to Tumor Antigens; Regulation of the Immune Response to Tumor Cells, Immunotherapy and Biomodulators, and Immunotherapy and Immunoprophylaxis.

  11. Immune System and Disorders

    MedlinePlus

    Your immune system is a complex network of cells, tissues, and organs that work together to defend against germs. It ... t, to find and destroy them. If your immune system cannot do its job, the results can be ...

  12. Immune System Quiz

    MedlinePlus

    ... Homework? Here's Help White House Lunch Recipes Quiz: Immune System KidsHealth > For Kids > Quiz: Immune System Print A A A Text Size How much do you know about your immune system? Find out by taking this quiz! View Survey ...

  13. Aging changes in immunity

    MedlinePlus

    ... keeps your immune system strong. DO NOT smoke. Smoking weakens your immune system. Limit your intake of alcohol . Ask your provider how much alcohol is safe for you. Look into safety measures to prevent falls and injuries. A weak immune system can ...

  14. Immune Disorder HSCT Protocol

    ClinicalTrials.gov

    2016-01-09

    Immune Deficiency Disorders:; Severe Combined Immunodeficiency; Chronic Granulomatous Disease; X-linked Agammaglobulinemia; Wiskott-Aldrich Syndrome; Hyper-IgM; DiGeorge Syndrome; Chediak-Higashi Syndrome; Common Variable Immune Deficiency; Immune Dysregulatory Disorder:; Hemophagocytic Lymphohistiocytosis; IPEX; Autoimmune Lymphoproliferative Syndrome; X-linked Lymphoproliferative Syndrome

  15. The Immune System Game

    ERIC Educational Resources Information Center

    Work, Kirsten A.; Gibbs, Melissa A.; Friedman, Erich J.

    2015-01-01

    We describe a card game that helps introductory biology students understand the basics of the immune response to pathogens. Students simulate the steps of the immune response with cards that represent the pathogens and the cells and molecules mobilized by the immune system. In the process, they learn the similarities and differences between the…

  16. Plant immunity: the EDS1 regulatory node.

    PubMed

    Wiermer, Marcel; Feys, Bart J; Parker, Jane E

    2005-08-01

    ENHANCED DISEASE SUSCEPTIBILITY 1 (EDS1) and its interacting partner, PHYTOALEXIN DEFICIENT 4 (PAD4), constitute a regulatory hub that is essential for basal resistance to invasive biotrophic and hemi-biotrophic pathogens. EDS1 and PAD4 are also recruited by Toll-Interleukin-1 receptor (TIR)-type nucleotide binding-leucine rich repeat (NB-LRR) proteins to signal isolate-specific pathogen recognition. Recent work points to a fundamental role of EDS1 and PAD4 in transducing redox signals in response to certain biotic and abiotic stresses. These intracellular proteins are important activators of salicylic acid (SA) signaling and also mediate antagonism between the jasmonic acid (JA) and ethylene (ET) defense response pathways. EDS1 forms several molecularly and spatially distinct complexes with PAD4 and a newly discovered in vivo signaling partner, SENESCENCE ASSOCIATED GENE 101 (SAG101). Together, EDS1, PAD4 and SAG101 provide a major barrier to infection by both host-adapted and non-host pathogens.

  17. [The ageing immune system].

    PubMed

    Djukic, M; Nau, R; Sieber, C

    2014-10-01

    The aging of the immune system, also called immunosenescence, contributes to the increased morbidity and mortality from infections, autoimmune diseases and cancer as well as to the low efficacy of vaccination in elderly persons. Immunosenescence is characterized by a decrease in cell-mediated immune function and by reduced humoral immune responses caused by age-related changes in the innate immune system and age-dependent defects in T-and B-cell function. This paper gives an overview of the most important modifications in the different compartments of the immune system during the ageing process.

  18. [The ageing immune system].

    PubMed

    Djukic, M; Nau, R; Sieber, C

    2014-10-01

    The aging of the immune system, also called immunosenescence, contributes to the increased morbidity and mortality from infections, autoimmune diseases and cancer as well as to the low efficacy of vaccination in elderly persons. Immunosenescence is characterized by a decrease in cell-mediated immune function and by reduced humoral immune responses caused by age-related changes in the innate immune system and age-dependent defects in T-and B-cell function. This paper gives an overview of the most important modifications in the different compartments of the immune system during the ageing process. PMID:25254392

  19. Sequential Immune Responses: The Weapons of Immunity

    PubMed Central

    Mills, Charles D.; Ley, Klaus; Buchmann, Kurt; Canton, Johnathan

    2016-01-01

    Sequential immune responses (SIR) is a new model that describes what ‘immunity’ means in higher animals. Existing models, such as self/nonself discrimination or danger, focus on how immune responses are initiated. However, initiation is not protection. SIR describes the actual immune responses that provide protection. SIR resulted from a comprehensive analysis of the evolution of immune systems that revealed that several very different types of host innate responses occur (and at different tempos) which together provide host protection. SIR1 uses rapidly activated enzymes like the NADPH oxidases and is present in all animal cells. SIR2 is mediated by the first ‘immune’ cells: macrophage-like cells. SIR3 evolved in animals like invertebrates and provides enhanced protection through advanced macrophage recognition and killing of pathogens and through other innate immune cells such as neutrophils. Finally, in vertebrates, macrophages developed SIR4: the ability to present antigens to T cells. Though much slower than SIR1–3, adaptive responses provide a unique new protection for higher vertebrates. Importantly, newer SIR responses were added on top of older, evolutionarily conserved functions to provide ‘layers’ of host protection. SIR transcends existing models by elucidating the different weapons of immunity that provide host protection in higher animals. PMID:25871013

  20. Neural circuitry and immunity.

    PubMed

    Pavlov, Valentin A; Tracey, Kevin J

    2015-12-01

    Research during the last decade has significantly advanced our understanding of the molecular mechanisms at the interface between the nervous system and the immune system. Insight into bidirectional neuro-immune communication has characterized the nervous system as an important partner of the immune system in the regulation of inflammation. Neuronal pathways, including the vagus nerve-based inflammatory reflex, are physiological regulators of immune function and inflammation. In parallel, neuronal function is altered in conditions characterized by immune dysregulation and inflammation. Here, we review these regulatory mechanisms and describe the neural circuitry modulating immunity. Understanding these mechanisms reveals possibilities to use targeted neuromodulation as a therapeutic approach for inflammatory and autoimmune disorders. These findings and current clinical exploration of neuromodulation in the treatment of inflammatory diseases define the emerging field of Bioelectronic Medicine.

  1. Origins of adaptive immunity.

    PubMed

    Liongue, Clifford; John, Liza B; Ward, Alister

    2011-01-01

    Adaptive immunity, involving distinctive antibody- and cell-mediated responses to specific antigens based on "memory" of previous exposure, is a hallmark of higher vertebrates. It has been argued that adaptive immunity arose rapidly, as articulated in the "big bang theory" surrounding its origins, which stresses the importance of coincident whole-genome duplications. Through a close examination of the key molecules and molecular processes underpinning adaptive immunity, this review suggests a less-extreme model, in which adaptive immunity emerged as part of longer evolutionary journey. Clearly, whole-genome duplications provided additional raw genetic materials that were vital to the emergence of adaptive immunity, but a variety of other genetic events were also required to generate some of the key molecules, whereas others were preexisting and simply co-opted into adaptive immunity.

  2. Origins of adaptive immunity.

    PubMed

    Liongue, Clifford; John, Liza B; Ward, Alister

    2011-01-01

    Adaptive immunity, involving distinctive antibody- and cell-mediated responses to specific antigens based on "memory" of previous exposure, is a hallmark of higher vertebrates. It has been argued that adaptive immunity arose rapidly, as articulated in the "big bang theory" surrounding its origins, which stresses the importance of coincident whole-genome duplications. Through a close examination of the key molecules and molecular processes underpinning adaptive immunity, this review suggests a less-extreme model, in which adaptive immunity emerged as part of longer evolutionary journey. Clearly, whole-genome duplications provided additional raw genetic materials that were vital to the emergence of adaptive immunity, but a variety of other genetic events were also required to generate some of the key molecules, whereas others were preexisting and simply co-opted into adaptive immunity. PMID:21395512

  3. Feeding the immune system.

    PubMed

    Calder, Philip C

    2013-08-01

    A well-functioning immune system is key to providing good defence against pathogenic organisms and to providing tolerance to non-threatening organisms, to food components and to self. The immune system works by providing an exclusion barrier, by identifying and eliminating pathogens and by identifying and tolerating non-threatening sources of antigens, and by maintaining a memory of immunological encounters. The immune system is complex involving many different cell types distributed throughout the body and many different chemical mediators some of which are involved directly in defence while others have a regulatory role. Babies are born with an immature immune system that fully develops in the first few years of life. Immune competence can decline with ageing. The sub-optimal immune competence that occurs early and late in life increases susceptibility to infection. Undernutrition decreases immune defences, making an individual more susceptible to infection. However, the immune response to an infection can itself impair nutritional status and alter body composition. Practically all forms of immunity are affected by protein-energy malnutrition, but non-specific defences and cell-mediated immunity are most severely affected. Micronutrient deficiencies impair immune function. Here, vitamins A, D and E, and Zn, Fe and Se are discussed. The gut-associated lymphoid tissue is especially important in health and well-being because of its close proximity to a large and diverse population of organisms in the gastrointestinal tract and its exposure to food constituents. Certain probiotic bacteria which modify the gut microbiota enhance immune function in laboratory animals and may do so in human subjects.

  4. Clinical immunity to malaria.

    PubMed

    Schofield, Louis; Mueller, Ivo

    2006-03-01

    Under appropriate conditions of transmission intensity, functional immunity to malaria appears to be acquired in distinct stages. The first phase reduces the likelihood of severe or fatal disease; the second phase limits the clinical impact of 'mild' malaria; and the third provides partial but incomplete protection against pathogen burden. These findings suggest clinical immunity to mortality and morbidity is acquired earlier, with greater ease, and via distinct mechanisms as compared to anti-parasite immunity, which is more difficult to achieve, takes longer and is only ever partially efficacious. The implications of this view are significant in that current vaccination strategies aim predominantly to achieve anti-parasite immunity, although imparting clinical immunity is the public health objective. Despite enormous relevance for global public health, the mechanisms governing these processes remain obscure. Four candidate mechanisms might mediate clinical immunity, namely immunity to cytoadherence determinants, tolerance to toxins, acquired immunity to toxins, and immunoregulation. This review addresses the targets and determinants of clinical immunity, and considers the implications for vaccine development.

  5. Immunity, ageing and cancer

    PubMed Central

    Derhovanessian, Evelyna; Solana, Rafael; Larbi, Anis; Pawelec, Graham

    2008-01-01

    Compromised immunity contributes to the decreased ability of the elderly to control infectious disease and to their generally poor response to vaccination. It is controversial as to how far this phenomenon contributes to the well-known age-associated increase in the occurrence of many cancers in the elderly. However, should the immune system be important in controlling cancer, for which there is a great deal of evidence, it is logical to propose that dysfunctional immunity in the elderly would contribute to compromised immunosurveillance and increased cancer occurrence. The chronological age at which immunosenescence becomes clinically important is known to be influenced by many factors, including the pathogen load to which individuals are exposed throughout life. It is proposed here that the cancer antigen load may have a similar effect on "immune exhaustion" and that pathogen load and tumor load may act additively to accelerate immunosenescence. Understanding how and why immune responsiveness changes in humans as they age is essential for developing strategies to prevent or restore dysregulated immunity and assure healthy longevity, clearly possible only if cancer is avoided. Here, we provide an overview of the impact of age on human immune competence, emphasizing T-cell-dependent adaptive immunity, which is the most sensitive to ageing. This knowledge will pave the way for rational interventions to maintain or restore appropriate immune function not only in the elderly but also in the cancer patient. PMID:18816370

  6. Improving immunization strategies

    NASA Astrophysics Data System (ADS)

    Gallos, Lazaros K.; Liljeros, Fredrik; Argyrakis, Panos; Bunde, Armin; Havlin, Shlomo

    2007-04-01

    We introduce an immunization method where the percentage of required vaccinations for immunity are close to the optimal value of a targeted immunization scheme of highest degree nodes. Our strategy retains the advantage of being purely local, without the need for knowledge on the global network structure or identification of the highest degree nodes. The method consists of selecting a random node and asking for a neighbor that has more links than himself or more than a given threshold and immunizing him. We compare this method to other efficient strategies on three real social networks and on a scale-free network model and find it to be significantly more effective.

  7. Innate Immunity in Disease

    PubMed Central

    Elliott, David E.; Siddique, Sana S.; Weinstock, Joel V.

    2014-01-01

    Cells can innately recognize generic products of viruses, bacteria, fungi, or injured tissue by engagement of pattern recognition receptors. Innate immune cells rapidly respond to this engagement in order to control commensals, thwart pathogens and/or prompt repair. Insufficient or excessive activation of the innate immune response results in disease. This review focuses on pattern recognition receptors and cells of the innate immune system important for intestinal function. Our improving knowledge pertaining to this important aspect of our immune response is opening potential important new therapeutic opportunities for the treatment of disease. PMID:24632348

  8. Trade-off between growth and immunity: role of brassinosteroids.

    PubMed

    Lozano-Durán, Rosa; Zipfel, Cyril

    2015-01-01

    A balance between growth and immunity exists in plants. Recently, the growth-promoting hormones brassinosteroids (BR) have emerged as crucial regulators of the growth-immunity trade-off, although the molecular mechanisms underlying this role remained unclear. New evidence obtained from the model plant Arabidopsis thaliana points at an indirect crosstalk between BR signaling and immunity, mediated by the transcription factors BZR1 and HBI1, which suppress immunity upon BR perception. The core transcriptional cascade formed by BZR1 and HBI1 seems to act as a regulatory hub on which multiple signaling inputs impinge, ensuring effective fine-tuning of the trade-off between growth and immunity in a timely and cost-efficient manner.

  9. An extracellular subtilase switch for immune priming in Arabidopsis.

    PubMed

    Ramírez, Vicente; López, Ana; Mauch-Mani, Brigitte; Gil, Ma José; Vera, Pablo

    2013-01-01

    In higher eukaryotes, induced resistance associates with acquisition of a priming state of the cells for a more effective activation of innate immunity; however, the nature of the components for mounting this type of immunological memory is not well known. We identified an extracellular subtilase from Arabidopsis, SBT3.3, the overexpression of which enhances innate immune responses while the loss of function compromises them. SBT3.3 expression initiates a durable autoinduction mechanism that promotes chromatin remodeling and activates a salicylic acid(SA)-dependent mechanism of priming of defense genes for amplified response. Moreover, SBT3.3 expression-sensitized plants for enhanced expression of the OXI1 kinase gene and activation of MAP kinases following pathogen attack, providing additional clues for the regulation of immune priming by SBT3.3. Conversely, in sbt3.3 mutant plants pathogen-mediated induction of SA-related defense gene expression is drastically reduced and activation of MAP kinases inhibited. Moreover, chromatin remodeling of defense-related genes normally associated with activation of an immune priming response appear inhibited in sbt3.3 plants, further indicating the importance of the extracellular SBT3.3 subtilase in the establishment of immune priming. Our results also point to an epigenetic control in the regulation of plant immunity, since SBT3.3 is up-regulated and priming activated when epigenetic control is impeded. SBT3.3 represents a new regulator of primed immunity.

  10. Immunizations. Position Statement. Revised

    ERIC Educational Resources Information Center

    Bobo, Nichole; Garrett, Jennifer; Teskey, Carmen; Duncan, Kay; Strasser, Kathy; Burrows-Mezu, Alicia L.

    2015-01-01

    It is the position of the National Association of School Nurses (NASN) that immunizations are essential to primary prevention of disease from infancy through adulthood. Promotion of immunizations by the registered professional school nurse (hereinafter referred to as school nurse) is central to the public health focus of school nursing practice…

  11. Innate immunity and adjuvants

    PubMed Central

    Akira, Shizuo

    2011-01-01

    Innate immunity was for a long time considered to be non-specific because the major function of this system is to digest pathogens and present antigens to the cells involved in acquired immunity. However, recent studies have shown that innate immunity is not non-specific, but is instead sufficiently specific to discriminate self from pathogens through evolutionarily conserved receptors, designated Toll-like receptors (TLRs). Indeed, innate immunity has a crucial role in early host defence against invading pathogens. Furthermore, TLRs were found to act as adjuvant receptors that create a bridge between innate and adaptive immunity, and to have important roles in the induction of adaptive immunity. This paradigm shift is now changing our thinking on the pathogenesis and treatment of infectious, immune and allergic diseases, as well as cancers. Besides TLRs, recent findings have revealed the presence of a cytosolic detector system for invading pathogens. I will review the mechanisms of pathogen recognition by TLRs and cytoplasmic receptors, and then discuss the roles of these receptors in the development of adaptive immunity in response to viral infection. PMID:21893536

  12. Neuroendocrine-immune interactions.

    PubMed

    Marsh, J A; Scanes, C G

    1994-07-01

    The role of the neuroendocrine system in influencing both immune development and function has become an area of active research within many model systems, including the chicken. It is now clear that the neuroendocrine system can exert immediate feedback regulation on the immune system as well as control specific aspects of immune differentiation and development. The primary lymphoid organs of avian species (i.e., the thymus and the bursa of Fabricius) are also known to function as endocrine organs. These produce hormonal products that influence the development of lymphoid cells and that may feed back on the neuroendocrine system. In conjunction with the endocrine activities of the primary lymphoid organs, immune and accessory cells are known to produce a variety of secreted products or cytokines that have the potential not only for the regulation of immune function but also for mediating neuroendocrine activities. Finally, it has been demonstrated in a variety of species that leukocytes are capable of producing endocrine mediators previously believed to be produced only under the direct control of the hypothalamic-pituitary axis. Thus, there are numerous possibilities for bidirectional interactions between the immune and neuroendocrine systems. This discussion focuses primarily on these interactions with an emphasis on the means by which the hormonal mediators, growth hormone and thyroid hormone, may affect the thymus and the thymic microenvironment. The role of the adrenocorticoids and gonadal steroids in regulating immune function and their involvement in immune feedback circuits are also discussed.

  13. The genetics of immunity.

    PubMed

    Lazzaro, Brian P; Schneider, David S

    2014-06-17

    In this commentary, Brian P. Lazzaro and David S. Schneider examine the topic of the Genetics of Immunity as explored in this month's issues of GENETICS and G3: Genes|Genomes|Genetics. These inaugural articles are part of a joint Genetics of Immunity collection (ongoing) in the GSA journals.

  14. Immunization alters body odor.

    PubMed

    Kimball, Bruce A; Opiekun, Maryanne; Yamazaki, Kunio; Beauchamp, Gary K

    2014-04-10

    Infections have been shown to alter body odor. Because immune activation accompanies both infection and immunization, we tested the hypothesis that classical immunization might similarly result in the alteration of body odors detectable by trained biosensor mice. Using a Y-maze, we trained biosensor mice to distinguish between urine odors from rabies-vaccinated (RV) and unvaccinated control mice. RV-trained mice generalized this training to mice immunized with the equine West Nile virus (WNV) vaccine compared with urine of corresponding controls. These results suggest that there are similarities between body odors of mice immunized with these two vaccines. This conclusion was reinforced when mice could not be trained to directly discriminate between urine odors of RV- versus WNV-treated mice. Next, we trained biosensor mice to discriminate the urine odors of mice treated with lipopolysaccharide (LPS; a general elicitor of innate immunological responses) from the urine of control mice. These LPS-trained biosensors could distinguish between the odors of LPS-treated mouse urine and RV-treated mouse urine. Finally, biosensor mice trained to distinguish between the odors of RV-treated mouse urine and control mouse urine did not generalize this training to discriminate between the odors of LPS-treated mouse urine and control mouse urine. From these experiments, we conclude that: (1) immunization alters urine odor in similar ways for RV and WNV immunizations; and (2) immune activation with LPS also alters urine odor but in ways different from those of RV and WNV. PMID:24524972

  15. Immunity and Nutrition.

    ERIC Educational Resources Information Center

    Dupin, Henri; Guerin, Nicole

    1990-01-01

    The three articles in this issue of a periodical focussed on various aspects of the life and health of children in the tropics concern: (1) immune defenses; (2) interactions between nutrition disorders and infection; and (3) immunity and vaccination. The science of immunology has progressed rapidly in recent years. A brief review of present…

  16. The Genetics of Immunity

    PubMed Central

    Lazzaro, Brian P.; Schneider, David S.

    2014-01-01

    In this commentary, Brian P. Lazzaro and David S. Schneider examine the topic of the Genetics of Immunity as explored in this month's issues of GENETICS and G3: Genes|Genomes|Genetics. These inaugural articles are part of a joint Genetics of Immunity collection (ongoing) in the GSA journals. PMID:24939182

  17. Chemoimmunotherapy: reengineering tumor immunity.

    PubMed

    Chen, Gang; Emens, Leisha A

    2013-02-01

    Cancer chemotherapy drugs have long been considered immune suppressive. However, more recent data indicate that some cytotoxic drugs effectively treat cancer in part by facilitating an immune response to the tumor when given at the standard dose and schedule. These drugs induce a form of tumor cell death that is immunologically active, thereby inducing an adaptive immune response specific for the tumor. In addition, cancer chemotherapy drugs can promote tumor immunity through ancillary and largely unappreciated immunologic effects on both the malignant and normal host cells present within the tumor microenvironment. These more subtle immunomodulatory effects are dependent on the drug itself, its dose, and its schedule in relation to an immune-based intervention. The recent approvals of two new immune-based therapies for prostate cancer and melanoma herald a new era in cancer treatment and have led to heightened interest in immunotherapy as a valid approach to cancer treatment. A detailed understanding of the cellular and molecular basis of interactions between chemotherapy drugs and the immune system is essential for devising the optimal strategy for integrating new immune-based therapies into the standard of care for various cancers, resulting in the greatest long-term clinical benefit for cancer patients. PMID:23389507

  18. Swine immune system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Probably no area of veterinary medicine has seen a greater explosion in knowledge then the immune system and its implications in disease and vaccination. In this chapter on the Swine Immune System for the 10th Edition of Diseases of Swine we expand on the information provided in past editions by in...

  19. Adaptive immunity to fungi.

    PubMed

    Verma, Akash; Wüthrich, Marcel; Deepe, George; Klein, Bruce

    2014-11-06

    Life-threatening fungal infections have risen sharply in recent years, owing to the advances and intensity of medical care that may blunt immunity in patients. This emerging crisis has created the growing need to clarify immune defense mechanisms against fungi with the ultimate goal of therapeutic intervention. We describe recent insights in understanding the mammalian immune defenses that are deployed against pathogenic fungi. We focus on adaptive immunity to the major medically important fungi and emphasize three elements that coordinate the response: (1) dendritic cells and subsets that are mobilized against fungi in various anatomical compartments; (2) fungal molecular patterns and their corresponding receptors that signal responses and shape the differentiation of T-cell subsets and B cells; and, ultimately (3) the effector and regulatory mechanisms that eliminate these invaders while constraining collateral damage to vital tissue. These insights create a foundation for the development of new, immune-based strategies for prevention or enhanced clearance of systemic fungal diseases.

  20. Autophagy and Immune Senescence.

    PubMed

    Zhang, Hanlin; Puleston, Daniel J; Simon, Anna Katharina

    2016-08-01

    With extension of the average lifespan, aging has become a heavy burden in society. Immune senescence is a key risk factor for many age-related diseases such as cancer and increased infections in the elderly, and hence has elicited much attention in recent years. As our body's guardian, the immune system maintains systemic health through removal of pathogens and damage. Autophagy is an important cellular 'clearance' process by which a cell internally delivers damaged organelles and macromolecules to lysosomes for degradation. Here, we discuss the most current knowledge of how impaired autophagy can lead to cellular and immune senescence. We also provide an overview, with examples, of the clinical potential of exploiting autophagy to delay immune senescence and/or rejuvenate immunity to treat various age-related diseases.

  1. Autophagy genes in immunity

    PubMed Central

    Virgin, Herbert W; Levine, Beth

    2009-01-01

    In its classical form, autophagy is a pathway by which cytoplasmic constituents, including intracellular pathogens, are sequestered in a double-membrane–bound autophagosome and delivered to the lysosome for degradation. This pathway has been linked to diverse aspects of innate and adaptive immunity, including pathogen resistance, production of type I interferon, antigen presentation, tolerance and lymphocyte development, as well as the negative regulation of cytokine signaling and inflammation. Most of these links have emerged from studies in which genes encoding molecules involved in autophagy are inactivated in immune effector cells. However, it is not yet known whether all of the critical functions of such genes in immunity represent ‘classical autophagy’ or possible as-yet-undefined autophagolysosome-independent functions of these genes. This review summarizes phenotypes that result from the inactivation of autophagy genes in the immune system and discusses the pleiotropic functions of autophagy genes in immunity. PMID:19381141

  2. Behavioral Immunity in Insects

    PubMed Central

    de Roode, Jacobus C.; Lefèvre, Thierry

    2012-01-01

    Parasites can dramatically reduce the fitness of their hosts, and natural selection should favor defense mechanisms that can protect hosts against disease. Much work has focused on understanding genetic and physiological immunity against parasites, but hosts can also use behaviors to avoid infection, reduce parasite growth or alleviate disease symptoms. It is increasingly recognized that such behaviors are common in insects, providing strong protection against parasites and parasitoids. We review the current evidence for behavioral immunity in insects, present a framework for investigating such behavior, and emphasize that behavioral immunity may act through indirect rather than direct fitness benefits. We also discuss the implications for host-parasite co-evolution, local adaptation, and the evolution of non-behavioral physiological immune systems. Finally, we argue that the study of behavioral immunity in insects has much to offer for investigations in vertebrates, in which this topic has traditionally been studied. PMID:26466629

  3. Autophagy and Immune Senescence.

    PubMed

    Zhang, Hanlin; Puleston, Daniel J; Simon, Anna Katharina

    2016-08-01

    With extension of the average lifespan, aging has become a heavy burden in society. Immune senescence is a key risk factor for many age-related diseases such as cancer and increased infections in the elderly, and hence has elicited much attention in recent years. As our body's guardian, the immune system maintains systemic health through removal of pathogens and damage. Autophagy is an important cellular 'clearance' process by which a cell internally delivers damaged organelles and macromolecules to lysosomes for degradation. Here, we discuss the most current knowledge of how impaired autophagy can lead to cellular and immune senescence. We also provide an overview, with examples, of the clinical potential of exploiting autophagy to delay immune senescence and/or rejuvenate immunity to treat various age-related diseases. PMID:27395769

  4. Recommended Immunizations for Adults 50+

    MedlinePlus

    ... page please turn Javascript on. Health Screenings and Immunizations Recommended Immunizations For Adults 50+ The content in this section ... out more, visit How Vaccines Prevent Disease . Vaccines, Vaccinations, and Immunizations Understanding the difference between vaccines, vaccinations, ...

  5. Identification of quantitative trait loci controlling gene expression during the innate immunity response of soybean

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Microbe associated molecular pattern (MAMP)-triggered immunity (MTI) is an important component of the plant innate immunity response to invading pathogens. However, most of our knowledge of MTI comes from studies of model systems with relatively little work done with crop plants. In this work, we re...

  6. Immunity in urogenital protozoa.

    PubMed

    Malla, N; Goyal, K; Dhanda, R S; Yadav, M

    2014-09-01

    Innate and adaptive immunity play a significant role in urogenital infections. Innate immunity is provided by the epithelial cells and mucus lining along with acidic pH, which forms a strong physical barrier against the pathogens in female reproductive tract. Cells of innate immune system, antimicrobial peptides, cytokines, chemokines and adaptive immunity in the reproductive tract are evolved during infection, and a pro-inflammatory response is generated to fight against the invading pathogen Trichomonas vaginalis, a primary urogenital protozoa, the etiological agent of human trichomoniasis, a curable sexually transmitted infection. The involvement of the urogenital tract by other protozoal infections such as P. falciparum, Trypanosoma, Leishmania, Toxoplasma, Entamoeba histolytica and Acanthamoeba infection is rarely reported. Trichomonas induce pro-inflammatory and immunosuppressive responses in infected subjects. Multifactorial pathogenic mechanisms including parasite adherence, cysteine proteases, lipophosphoglycan, free radical, cytokine generation and Toll-like receptors appear to interplay with the induction of local and systemic immune responses that ultimately determine the outcome of the infection. However, the involvement of urogenital pathogen-specific immune mechanisms and effect of normal local resident flora on the outcome (symptomatic vs. asymptomatic) of infection are poorly understood. Moreover, immune interactions in trichomoniasis subjects co-infected with bacterial and viral pathogens need to be elucidated.

  7. No hormone to rule them all: Interactions of plant hormones during the responses of plants to pathogens.

    PubMed

    Shigenaga, Alexandra M; Argueso, Cristiana T

    2016-08-01

    Plant hormones are essential regulators of plant growth and immunity. In the last few decades, a vast amount of information has been obtained detailing the role of different plant hormones in immunity, and how they work together to ultimately shape the outcomes of plant pathogen interactions. Here we provide an overview on the roles of the main classes of plant hormones in the regulation of plant immunity, highlighting their metabolic and signaling pathways and how plants and pathogens utilize these pathways to activate or suppress defence.

  8. Geographical variation in parasitism shapes larval immune function in a phytophagous insect

    NASA Astrophysics Data System (ADS)

    Vogelweith, Fanny; Dourneau, Morgane; Thiéry, Denis; Moret, Yannick; Moreau, Jérôme

    2013-12-01

    Two of the central goals of immunoecology are to understand natural variation in the immune system among populations and to identify those selection pressures that shape immune traits. Maintenance of the immune system can be costly, and both food quality and parasitism selection pressure are factors potentially driving immunocompetence. In tritrophic interactions involving phytophagous insects, host plants, and natural enemies, the immunocompetence of phytophagous insects is constrained by selective forces from both the host plants and the natural enemies. Here, we assessed the roles of host plants and natural enemies as selective pressures on immune variation among natural populations of Lobesia botrana. Our results showed marked geographical variation in immune defenses and parasitism among different natural populations. Larval immune functions were dependent of the host plant quality and were positively correlated to parasitism, suggesting that parasitoids select for greater investment into immunity in moth. Furthermore, investment in immune defense was negatively correlated with body size, suggesting that it is metabolically expensive. The findings emphasize the roles of host plants and parasitoids as selective forces shaping host immune functions in natural conditions. We argue that kinds of study are central to understanding natural variations in immune functions, and the selective forces beyond.

  9. Reflex control of immunity

    PubMed Central

    Tracey, Kevin J.

    2015-01-01

    Inflammation can cause damage and even death. What controls this primitive and potentially lethal innate immune response to injury and infection? Molecular and neurophysiological studies during the past decade have revealed a pivotal answer: immunity is coordinated by neural circuits that operate reflexively The afferent arc of the reflex consists of nerves that sense injury and infection. This activates efferent neural circuits, including the cholinergic anti-inflammatory pathway that modulate immune responses and the progression of inflammatory diseases. It might be possible to develop therapeutics that target neural networks for the treatment of inflammatory disorders. PMID:19461672

  10. Adaptive immunity to fungi.

    PubMed

    Wüthrich, Marcel; Deepe, George S; Klein, Bruce

    2012-01-01

    Only a handful of the more than 100,000 fungal species on our planet cause disease in humans, yet the number of life-threatening fungal infections in patients has recently skyrocketed as a result of advances in medical care that often suppress immunity intensely. This emerging crisis has created pressing needs to clarify immune defense mechanisms against fungi, with the ultimate goal of therapeutic applications. Herein, we describe recent insights in understanding the mammalian immune defenses deployed against pathogenic fungi. The review focuses on adaptive immune responses to the major medically important fungi and emphasizes how dendritic cells and subsets in various anatomic compartments respond to fungi, recognize their molecular patterns, and signal responses that nurture and shape the differentiation of T cell subsets and B cells. Also emphasized is how the latter deploy effector and regulatory mechanisms that eliminate these nasty invaders while also constraining collateral damage to vital tissue.

  11. Immune System (For Parents)

    MedlinePlus

    ... lock onto them. T cells are like the soldiers, destroying the invaders that the intelligence system has ... can't be prevented, you can help your child's immune system stay stronger and fight illnesses by ...

  12. Antiviral immunity in amphibians.

    PubMed

    Chen, Guangchun; Robert, Jacques

    2011-11-01

    Although a variety of virus species can infect amphibians, diseases caused by ranaviruses ([RVs]; Iridoviridae) have become prominent, and are a major concern for biodiversity, agriculture and international trade. The relatively recent and rapid increase in prevalence of RV infections, the wide range of host species infected by RVs, the variability in host resistance among population of the same species and among different developmental stages, all suggest an important involvement of the amphibian immune system. Nevertheless, the roles of the immune system in the etiology of viral diseases in amphibians are still poorly investigated. We review here the current knowledge of antiviral immunity in amphibians, focusing on model species such as the frog Xenopus and the salamander (Ambystoma tigrinum), and on recent progress in generating tools to better understand how host immune defenses control RV infections, pathogenicity, and transmission.

  13. Immunization Action Coalition

    MedlinePlus

    ... IAC | Contact | A-Z Index | Donate | Shop | SUBSCRIBE Immunization Action Coalition Handouts for Patients & Staff A-Z ... Index Supplies Checklist Administering Vaccines Temperature Logs Adult Vaccination Topics of Interest Documenting Vaccination Translations Parent Handouts ...

  14. Pneumonia - weakened immune system

    MedlinePlus

    If you have a weakened immune system, you may receive daily antibiotics to prevent some types of pneumonia. Ask your provider if you should receive the influenza (flu) and pneumococcal (pneumonia) vaccines. Practice ...

  15. Immunizations for Preterm Babies

    MedlinePlus

    ... Prevention Listen Español Text Size Email Print Share Immunizations For Preterm Babies Page Content Some parents of ... full-term and preterm babies. The hepatitis B vaccine deserves special mention. In most circumstances, the AAP ...

  16. Immunization Against Infectious Disease

    ERIC Educational Resources Information Center

    Mortimer, Edward A., Jr.

    1978-01-01

    The success of present and future immunization programs is endangered by public and physician complacency and by complex legal and ethical problems related to informed consent and responsibility for rare, vaccine-related injury. (BB)

  17. Exercise and immunity

    MedlinePlus

    ... immunity. Heavy, long-term exercise (such as marathon running and intense gym training) could actually cause harm. Studies have shown that people who follow a moderately energetic lifestyle, benefit most from starting (and sticking to) an exercise ...

  18. Mucosal immunization and adjuvants.

    PubMed

    Hasegawa, Hideki; van Reit, Elly; Kida, Hiroshi

    2015-01-01

    The goal of the influenza vaccine is to prevent influenza virus infection and control the yearly seasonal epidemic and pandemic. However, the presently available parenteral influenza vaccine induces only systemic humoral immunity, which does not prevent influenza virus infection on the mucosal surface. Secretary IGA antibodies play an important role in preventing natural infection. Moreover, the IgA antibody response mediates cross-protection against variant viruses in animal models. Thus, a mucosal influenza vaccine that induces mucosal immunity would be a powerful tool to protect individuals from the influenza virus. Although the function of the mucosal immune system, especially in the respiratory tract, is not completely understood, there are several studies underway to develop mucosal influenza vaccines. Here, we will review current knowledge concerning the induction of IgA, the role of B-cell production of influenza virus specific IgA antibodies in anti-influenza immunity, and the role of humoral memory responses induced upon vaccination.

  19. Vaccines (immunizations) - overview

    MedlinePlus

    ... mumps, and rubella (MMR) vaccine and the varicella (chickenpox) vaccine are examples. Killed (inactivated) vaccines are made from ... countries. Some countries require this record. COMMON VACCINES ... DTaP immunization (vaccine) Hepatitis A vaccine Hepatitis B ...

  20. Immune System 101

    MedlinePlus

    ... your healthy cells. How HIV Affects This Complex Process HIV disrupts this process by directly infecting the helper T-cells. Your ... T-cells are destroyed in the HIV replication process. For more information, see NIAID's The Immune System . ...

  1. Vaccines: Engineering immune evasion

    NASA Astrophysics Data System (ADS)

    Mascola, John R.

    2006-05-01

    One obstacle to realizing the promise of viral vectors for vaccine delivery is pre-existing immunity to such vectors. An adroit application of structure-based design points to a way around that problem.

  2. FastStats: Immunization

    MedlinePlus

    ... this? Submit What's this? Submit Button NCHS Home Immunization Recommend on Facebook Tweet Share Compartir Data are ... Percent of children 19-35 months old receiving vaccinations for: Diphtheria, Tetanus, Pertussis (4+ doses DTP, DT, ...

  3. Antiviral Immunity in Amphibians

    PubMed Central

    Chen, Guangchun; Robert, Jacques

    2011-01-01

    Although a variety of virus species can infect amphibians, diseases caused by ranaviruses ([RVs]; Iridoviridae) have become prominent, and are a major concern for biodiversity, agriculture and international trade. The relatively recent and rapid increase in prevalence of RV infections, the wide range of host species infected by RVs, the variability in host resistance among population of the same species and among different developmental stages, all suggest an important involvement of the amphibian immune system. Nevertheless, the roles of the immune system in the etiology of viral diseases in amphibians are still poorly investigated. We review here the current knowledge of antiviral immunity in amphibians, focusing on model species such as the frog Xenopus and the salamander (Ambystoma tigrinum), and on recent progress in generating tools to better understand how host immune defenses control RV infections, pathogenicity, and transmission. PMID:22163335

  4. IMMUNE RESPONSES IN VITRO

    PubMed Central

    Pierce, Carl W.; Solliday, Susan M.; Asofsky, Richard

    1972-01-01

    Suppression of Ig class-specific PFC responses by class-specific antibody to mouse immunoglobulin was studied in cultures of spleen cells from immunized mice. In contrast to cultures from normal mice where anti-µ suppressed responses in all Ig classes, anti-µ had progressively less suppressive effect on γ1 and γ2 responses in cultures from immunized mice with time after immunization. This was most pronounced at 10 days after immunization when anti-µ suppressed γM and γA responses, but had no or slight effect on γ1 or γ2 responses which were still suppressed with anti-γ1 and anti-γ2. These changes in precursor cell susceptibility to anti-µ were antigen specific. PMID:4536707

  5. CDPKs in immune and stress signaling

    PubMed Central

    Boudsocq, Marie; Sheen, Jen

    2012-01-01

    Ca2+ has long been recognized as a conserved second messenger and principal mediator in plant immune and stress responses. How Ca2+ signals are sensed and relayed into diverse primary and global signaling events is still largely unknown. Comprehensive analyses of the plant-specific multigene family of Ca2+-dependent protein kinases (CDPKs) are unraveling the molecular, cellular and genetic mechanisms of Ca2+ signaling. CDPKs, which exhibit overlapping and distinct expression patterns, sub-cellular localizations, substrate specificities and Ca2+ sensitivities, play versatile roles in the activation and repression of enzymes, channels and transcription factors. Here, we review the recent advances on the multifaceted functions of CDPKs in the complex immune and stress signaling networks, including oxidative burst, stomatal movements, hormonal signaling and gene regulation. PMID:22974587

  6. Immune reaction to propanidid.

    PubMed

    Christmas, D

    1984-05-01

    An adverse reaction to the intravenous anaesthetic agent propanidid is described in which the main features were hypotension, facial erythema, and abdominal pain. Changes in serum complement levels and differential white cell counts indicate that this was an immune reaction mediated by the classical complement pathway. The immune reaction apparently involved antibodies other than those of the IgE (reagin) class, and circumstantial evidence suggests that it was specific to propanidid rather than to the entire formulation or to Cremophor EL.

  7. Military Healthcare Battlefield Immunity.

    PubMed

    Kelly, J C

    2012-12-01

    The combatant soldier on the battlefield remains protected from any claim in negligence by the doctrine of combat immunity for any negligent act or omission they may make when fighting. In other words, the combatant soldier does not owe a fellow soldier a duty of care on the battlefield, as the duty of care is non-justiciable. However, the non-combatant Military Healthcare Professional, although sometimes operating in the same hostile circumstances as the fighting soldier, is unlikely to benefit from combat immunity for any clinical negligence on the battlefield. This is because they continue to owe their patient a duty of care, although this has not been tested in the courts. This paper considers if any military healthcare professional could ever benefit from combat immunity, which is unlikely due to their non-combatant status. Instead, this paper suggests that a modified form of immunity; namely, Military Healthcare Battlefield Immunity could be a new, unique and viable doctrine, however, this could only be granted in rare circumstances and to a much lesser degree than combat immunity.

  8. Immune mediated liver failure

    PubMed Central

    Wang, Xiaojing; Ning, Qin

    2014-01-01

    Liver failure is a clinical syndrome of various etiologies, manifesting as jaundice, encephalopathy, coagulopathy and circulatory dysfunction, which result in subsequent multiorgan failure. Clinically, liver failure is classified into four categories: acute, subacute, acute-on-chronic and chronic liver failure. Massive hepatocyte death is considered to be the core event in the development of liver failure, which occurs when the extent of hepatocyte death is beyond the liver regenerative capacity. Direct damage and immune-mediated liver injury are two major factors involved in this process. Increasing evidence has suggested the essential role of immune-mediated liver injury in the pathogenesis of liver failure. Here, we review the evolved concepts concerning the mechanisms of immune-mediated liver injury in liver failure from human and animal studies. Both innate and adaptive immunity, especially the interaction of various immune cells and molecules as well as death receptor signaling system are discussed. In addition, we highlight the concept of “immune coagulation”, which has been shown to be related to the disease progression and liver injury exacerbation in HBV related acute-on-chronic liver failure. PMID:26417328

  9. Mammalian Gut Immunity

    PubMed Central

    Chassaing, Benoit; Kumar, Manish; Baker, Mark T.; Singh, Vishal; Vijay-Kumar, Matam

    2016-01-01

    The mammalian intestinal tract is the largest immune organ in the body and comprises cells from non-hemopoietic (epithelia, Paneth cells, goblet cells) and hemopoietic (macrophages, dendritic cells, T-cells) origin, and is also a dwelling for trillions of microbes collectively known as the microbiota. The homeostasis of this large microbial biomass is prerequisite to maintain host health by maximizing beneficial symbiotic relationships and minimizing the risks of living in such close proximity. Both microbiota and host immune system communicate with each other to mutually maintain homeostasis in what could be called a “love–hate relationship.” Further, the host innate and adaptive immune arms of the immune system cooperate and compensate each other to maintain the equilibrium of a highly complex gut ecosystem in a stable and stringent fashion. Any imbalance due to innate or adaptive immune deficiency or aberrant immune response may lead to dysbiosis and low-grade to robust gut inflammation, finally resulting in metabolic diseases. PMID:25163502

  10. Innate immunity underlies symbiotic relationships.

    PubMed

    Kisseleva, E P

    2014-12-01

    Here, the modern data regarding interactions between normal microbiota and barrier tissues in plants, humans and animals are reviewed. The main homeostatic mechanisms responsible for interactions between epithelium and innate immune cells with symbiotic bacteria are described. A key step in this process is recognition of soluble microbial products by ligation to pattern-recognition receptors expressed on the host cells. As a result, epithelial cells secrete mucus, antibacterial peptides and immunoregulatory molecules. The main outcomes from immunological reactions towards symbiotic bacteria involve development of conditions for formation and maintenance of microbial biocenosis as well as providing safety for the host. Also, it is considered important to preserve and transfer beneficial bacteria to progeny.

  11. Innate immunity underlies symbiotic relationships.

    PubMed

    Kisseleva, E P

    2014-12-01

    Here, the modern data regarding interactions between normal microbiota and barrier tissues in plants, humans and animals are reviewed. The main homeostatic mechanisms responsible for interactions between epithelium and innate immune cells with symbiotic bacteria are described. A key step in this process is recognition of soluble microbial products by ligation to pattern-recognition receptors expressed on the host cells. As a result, epithelial cells secrete mucus, antibacterial peptides and immunoregulatory molecules. The main outcomes from immunological reactions towards symbiotic bacteria involve development of conditions for formation and maintenance of microbial biocenosis as well as providing safety for the host. Also, it is considered important to preserve and transfer beneficial bacteria to progeny. PMID:25716721

  12. Protective immune responses to fungal infections.

    PubMed

    Rivera, A

    2014-09-01

    The incidence of fungal infections has been on the rise over several decades. Fungal infections threaten animals, plants and humans alike and are thus of significant concern to scientists across disciplines. Over the last decade, significant advances on fungal immunology have lead to a better understanding of important mechanisms of host protection against fungi. In this article, I review recent advances of relevant mechanisms of immune-mediated protection to fungal infections.

  13. Immunizations climb, then falter.

    PubMed

    Kane, H

    1994-01-01

    The extended immunization campaign began in the mid 1980s and contributed to immunization of 4 out of every 5 infants worldwide, or 80% by the end of the 1980s. There was a slight relaxation of effort around 1990 and 1991, and declines occurred in 28 developing countries. In developing countries, 101 countries maintained or increased immunization in 1991. Rates dropped in Brazil and Venezuela and sub-Saharan Africa. Rates remained constant in 1992, except for the declines in women's tetanus immunization. Distribution is 4-5 times a year to 100 million infants. The savings in lives amounted to 3 million 1992, and further extension could have saved another 1.7 million. The cost in low income countries is $6 to $20, with an average of $15. Five visits are required for complete immunization into one dose; costs could then be reduced by 70%. Total annual costs amount to $2.2 to $2.4 billion for the United Nations Expanded Programme on Immunization. This sum amounts to 2% of public health expenditures in developing countries. The benefits are in reduction in health care costs and expanded productive potential of people. The measles vaccine alone reduced the death rate from 2.5 million in 1980 to 900,000 in 1990. Nonfatal measles morbidity was reduced from 75 million to 25 million for the same period. From averted measles incidents, the savings in treatment costs and productive potential are immeasurable. The first smallpox vaccine was developed in 1796 by Edward Jenner, but it took nearly two for final smallpox eradication in 1979 worldwide. Over the past 10 years, polio eradication has cost $1.4 billion, but without polio vaccines, the cost would reach $500 million annually. Refrigeration and transportation to remote areas has made immunization difficult. The development of low-dose vaccines that would maintain potency in tropical temperatures would be a welcome contribution.

  14. Ontogeny of Early Life Immunity

    PubMed Central

    Dowling, David J.; Levy, Ofer

    2014-01-01

    The human immune system is comprised of cellular and molecular components designed to coordinately prevent infection while avoiding potentially harmful inflammation and auto-immunity. Immunity varies with age, reflecting unique age-dependent challenges including fetal gestation, the neonatal phase and infancy. Herein, we review novel mechanistic insights into early life immunity, with emphasis on emerging models of human immune ontogeny, which may inform age-specific translational development of novel anti-infectives, immunomodulators and vaccines. PMID:24880460

  15. Immune memory in invertebrates.

    PubMed

    Milutinović, Barbara; Kurtz, Joachim

    2016-08-01

    Evidence for innate immune memory (or 'priming') in invertebrates has been accumulating over the last years. We here provide an in-depth review of the current state of evidence for immune memory in invertebrates, and in particular take a phylogenetic viewpoint. Invertebrates are a very heterogeneous group of animals and accordingly, evidence for the phenomenon of immune memory as well as the hypothesized molecular underpinnings differ largely for the diverse invertebrate taxa. The majority of research currently focuses on Arthropods, while evidence from many other groups of invertebrates is fragmentary or even lacking. We here concentrate on immune memory that is induced by pathogenic challenges, but also extent our view to a non-pathogenic context, i.e. allograft rejection, which can also show forms of memory and can inform us about general principles of specific self-nonself recognition. We discuss definitions of immune memory and a number of relevant aspects such as the type of antigens used, the route of exposure, and the kinetics of reactions following priming. PMID:27402055

  16. Immunity to Fish Rhabdoviruses

    PubMed Central

    Purcell, Maureen K.; Laing, Kerry J.; Winton, James R.

    2012-01-01

    Members of the family Rhabdoviridae are single-stranded RNA viruses and globally important pathogens of wild and cultured fish and thus relatively well studied in their respective hosts or other model systems. Here, we review the protective immune mechanisms that fish mount in response to rhabdovirus infections. Teleost fish possess the principal components of innate and adaptive immunity found in other vertebrates. Neutralizing antibodies are critical for long-term protection from fish rhabdoviruses, but several studies also indicate a role for cell-mediated immunity. Survival of acute rhabdoviral infection is also dependent on innate immunity, particularly the interferon (IFN) system that is rapidly induced in response to infection. Paradoxically, rhabdoviruses are sensitive to the effects of IFN but virulent rhabdoviruses can continue to replicate owing to the abilities of the matrix (M) protein to mediate host-cell shutoff and the non‑virion (NV) protein to subvert programmed cell death and suppress functional IFN. While many basic features of the fish immune response to rhabdovirus infections are becoming better understood, much less is known about how factors in the environment affect the ecology of rhabdovirus infections in natural populations of aquatic animals. PMID:22355456

  17. Immunity to fish rhabdoviruses.

    PubMed

    Purcell, Maureen K; Laing, Kerry J; Winton, James R

    2012-01-01

    Members of the family Rhabdoviridae are single-stranded RNA viruses and globally important pathogens of wild and cultured fish and thus relatively well studied in their respective hosts or other model systems. Here, we review the protective immune mechanisms that fish mount in response to rhabdovirus infections. Teleost fish possess the principal components of innate and adaptive immunity found in other vertebrates. Neutralizing antibodies are critical for long-term protection from fish rhabdoviruses, but several studies also indicate a role for cell-mediated immunity. Survival of acute rhabdoviral infection is also dependent on innate immunity, particularly the interferon (IFN) system that is rapidly induced in response to infection. Paradoxically, rhabdoviruses are sensitive to the effects of IFN but virulent rhabdoviruses can continue to replicate owing to the abilities of the matrix (M) protein to mediate host-cell shutoff and the non‑virion (NV) protein to subvert programmed cell death and suppress functional IFN. While many basic features of the fish immune response to rhabdovirus infections are becoming better understood, much less is known about how factors in the environment affect the ecology of rhabdovirus infections in natural populations of aquatic animals.

  18. Immunity to fish rhabdoviruses

    USGS Publications Warehouse

    Purcell, Maureen K.; Laing, Kerry J.; Winton, James R.

    2012-01-01

    Members of the family Rhabdoviridae are single-stranded RNA viruses and globally important pathogens of wild and cultured fish and thus relatively well studied in their respective hosts or other model systems. Here, we review the protective immune mechanisms that fish mount in response to rhabdovirus infections. Teleost fish possess the principal components of innate and adaptive immunity found in other vertebrates. Neutralizing antibodies are critical for long-term protection from fish rhabdoviruses, but several studies also indicate a role for cell-mediated immunity. Survival of acute rhabdoviral infection is also dependent on innate immunity, particularly the interferon (IFN) system that is rapidly induced in response to infection. Paradoxically, rhabdoviruses are sensitive to the effects of IFN but virulent rhabdoviruses can continue to replicate owing to the abilities of the matrix (M) protein to mediate host-cell shutoff and the non-virion (NV) protein to subvert programmed cell death and suppress functional IFN. While many basic features of the fish immune response to rhabdovirus infections are becoming better understood, much less is known about how factors in the environment affect the ecology of rhabdovirus infections in natural populations of aquatic animals.

  19. Immune memory in invertebrates.

    PubMed

    Milutinović, Barbara; Kurtz, Joachim

    2016-08-01

    Evidence for innate immune memory (or 'priming') in invertebrates has been accumulating over the last years. We here provide an in-depth review of the current state of evidence for immune memory in invertebrates, and in particular take a phylogenetic viewpoint. Invertebrates are a very heterogeneous group of animals and accordingly, evidence for the phenomenon of immune memory as well as the hypothesized molecular underpinnings differ largely for the diverse invertebrate taxa. The majority of research currently focuses on Arthropods, while evidence from many other groups of invertebrates is fragmentary or even lacking. We here concentrate on immune memory that is induced by pathogenic challenges, but also extent our view to a non-pathogenic context, i.e. allograft rejection, which can also show forms of memory and can inform us about general principles of specific self-nonself recognition. We discuss definitions of immune memory and a number of relevant aspects such as the type of antigens used, the route of exposure, and the kinetics of reactions following priming.

  20. Immune therapies for neuroblastoma.

    PubMed

    Navid, Fariba; Armstrong, Michael; Barfield, Raymond C

    2009-05-01

    Neuroblastoma, a solid tumor arising from developing cells of the sympathetic nervous system, is the most common extracranial tumor in children. The prognosis for high-risk neuroblastoma remains poor with conventional treatment, and new approaches are therefore being explored to treat this disease. One such alternative therapy that holds promise is immune therapy. We review here the recent advances in four types of immune therapy-cytokine, vaccine, antibody and cellular therapy-to treat neuroblastoma. We present preclinical research and clinical trials on several promising candidates such as IL-12, dendritic cell vaccines, anti-GD2 antibodies and allogeneic hematopoietic stem cell transplant. An optimal treatment plan for neuroblastoma will most likely involve multimodal approaches and combinations of immune therapies.

  1. Immune cells and angiogenesis.

    PubMed

    Ribatti, Domenico; Crivellato, Enrico

    2009-09-01

    Both innate and adaptive immune cells are involved in the mechanisms of endothelial cell proliferation, migration and activation, through the production and release of a large spectrum of pro-angiogenic mediators. These may create the specific microenvironment that favours an increased rate of tissue vascularization. In this review, we will focus on the immune cell component of the angiogenic process in inflammation and tumour growth. As angiogenesis is the result of a net balance between the activities exerted by positive and negative regulators, we will also provide information on some antiangiogenic properties of immune cells that may be utilized for a potential pharmacological use as antiangiogenic agents in inflammation as well as in cancer.

  2. Immune Therapies for Neuroblastoma

    PubMed Central

    Navid, Fariba; Armstrong, Michael; Barfield, Raymond C.

    2009-01-01

    Neuroblastoma, a solid tumor arising from developing cells of the sympathetic nervous system, is the most common extracranial tumor in children. The prognosis for high-risk neuroblastoma remains poor with conventional treatment, and new approaches are therefore being explored to treat this disease. One such alternative therapy that holds promise is immune therapy. We review here the recent advances in 4 types of immune therapy – cytokine, vaccine, antibody, and cellular therapy – to treat neuroblastoma. We present preclinical research and clinical trials on several promising candidates such as IL-12, dendritic cell vaccines, anti-GD2 antibodies, and allogeneic hematopoietic stem cell transplant. An optimal treatment plan for neuroblastoma will most likely involve multimodal approaches and combinations of immune therapies. PMID:19342881

  3. Vitamin D and immunity

    PubMed Central

    Gorman, Shelley; Geldenhuys, Sian; Hart, Prue H.

    2014-01-01

    Vitamin D deficiency has been linked to an increased risk of a wide range of adverse health outcomes. The active form of vitamin D has an important role in calcium metabolism and in bone mineralisation, but the evidence for other health outcomes is mixed, with the strongest effects seen in the weakest epidemiological study designs. There are plausible pathways whereby vitamin D deficiency can impair immune function, resulting in both overactivity and increased risk of autoimmune disease, as well as immune suppression with poorer resistance to infection. Vitamin D status may influence the bacterial flora that constitute the microbiome and affect immune function through this route. Exposure of the skin to ultraviolet radiation causes the production of a range of chemicals, including vitamin D, and new research is exploring possible vitamin D-independent immunomodulatory pathways. PMID:25580272

  4. Inflammatory bowel disease related innate immunity and adaptive immunity

    PubMed Central

    Huang, Yuan; Chen, Zhonge

    2016-01-01

    Inflammatory bowel disease (IBD) is a chronic nonspecific intestinal inflammatory disease, including ulcerative colitis (UC) and Crohn’s disease (CD). Its pathogenesis remains not yet clear. Current researchers believe that after environmental factors act on individuals with genetic susceptibility, an abnormal intestinal immune response is launched under stimulation of intestinal flora. However, previous studies only focused on adaptive immunity in the pathogenesis of IBD. Currently, roles of innate immune response in the pathogenesis of intestinal inflammation have also drawn much attention. In this study, IBD related innate immunity and adaptive immunity were explained, especially the immune mechanisms in the pathogenesis of IBD. PMID:27398134

  5. Mammalian glycosylation in immunity

    PubMed Central

    Marth, Jamey D.; Grewal, Prabhjit K.

    2009-01-01

    Glycosylation produces a diverse and abundant repertoire of glycans, which are collectively known as the glycome. Glycans are one of the four fundamental macromolecular components of all cells, and are highly regulated in the immune system. Their diversity reflects their multiple biological functions that encompass ligands for proteinaceous of receptors known as lectins. Since the discovery that selectins and their glycan ligands are important for the regulation of leukocyte trafficking, it has been shown that additional features of the vertebrate immune system are also controlled by endogenous cellular glycosylation. This Review focuses on the emerging immunological roles of the mammalian glycome. PMID:18846099

  6. Vaccines and Immunization Practice.

    PubMed

    Hogue, Michael D; Meador, Anna E

    2016-03-01

    Vaccines are among most cost-effective public health strategies. Despite effective vaccines for many bacterial and viral illnesses, tens of thousands of adults and hundreds of children die each year in the United States from vaccine-preventable diseases. Underutilization of vaccines requires rethinking the approach to incorporating vaccines into practice. Arguably, immunizations could be a part all health care encounters. Shared responsibility is paramount if deaths are to be reduced. This article reviews the available vaccines in the US market, as well as practice recommendations of the Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices.

  7. Transcriptome and Metabolite Profiling of the Infection Cycle of Zymoseptoria tritici on Wheat Reveals a Biphasic Interaction with Plant Immunity Involving Differential Pathogen Chromosomal Contributions and a Variation on the Hemibiotrophic Lifestyle Definition1[OPEN

    PubMed Central

    Rudd, Jason J.; Kanyuka, Kostya; Hassani-Pak, Keywan; Derbyshire, Mark; Andongabo, Ambrose; Devonshire, Jean; Lysenko, Artem; Saqi, Mansoor; Desai, Nalini M.; Powers, Stephen J.; Hooper, Juliet; Ambroso, Linda; Bharti, Arvind; Farmer, Andrew; Hammond-Kosack, Kim E.; Dietrich, Robert A.; Courbot, Mikael

    2015-01-01

    The hemibiotrophic fungus Zymoseptoria tritici causes Septoria tritici blotch disease of wheat (Triticum aestivum). Pathogen reproduction on wheat occurs without cell penetration, suggesting that dynamic and intimate intercellular communication occurs between fungus and plant throughout the disease cycle. We used deep RNA sequencing and metabolomics to investigate the physiology of plant and pathogen throughout an asexual reproductive cycle of Z. tritici on wheat leaves. Over 3,000 pathogen genes, more than 7,000 wheat genes, and more than 300 metabolites were differentially regulated. Intriguingly, individual fungal chromosomes contributed unequally to the overall gene expression changes. Early transcriptional down-regulation of putative host defense genes was detected in inoculated leaves. There was little evidence for fungal nutrient acquisition from the plant throughout symptomless colonization by Z. tritici, which may instead be utilizing lipid and fatty acid stores for growth. However, the fungus then subsequently manipulated specific plant carbohydrates, including fructan metabolites, during the switch to necrotrophic growth and reproduction. This switch coincided with increased expression of jasmonic acid biosynthesis genes and large-scale activation of other plant defense responses. Fungal genes encoding putative secondary metabolite clusters and secreted effector proteins were identified with distinct infection phase-specific expression patterns, although functional analysis suggested that many have overlapping/redundant functions in virulence. The pathogenic lifestyle of Z. tritici on wheat revealed through this study, involving initial defense suppression by a slow-growing extracellular and nutritionally limited pathogen followed by defense (hyper) activation during reproduction, reveals a subtle modification of the conceptual definition of hemibiotrophic plant infection. PMID:25596183

  8. Photodynamic immune modulation (PIM)

    NASA Astrophysics Data System (ADS)

    North, John R.; Hunt, David W. C.; Simkin, Guillermo O.; Ratkay, Leslie G.; Chan, Agnes H.; Lui, Harvey; Levy, Julia G.

    1999-09-01

    Photodynamic Therapy (PDT) is accepted for treatment of superficial and lumen-occluding tumors in regions accessible to activating light and is now known to be effective in closure of choroidal neovasculature in Age Related Macular Degeneration. PDT utilizes light absorbing drugs (photosensitizers) that generate the localized formation of reactive oxygen species after light exposure. In a number of systems, PDT has immunomodulatory effects; Photodynamic Immune Modulation (PIM). Using low- intensity photodynamic regimens applied over a large body surface area, progression of mouse autoimmune disease could be inhibited. Further, this treatment strongly inhibited the immunologically- medicated contact hypersensitivity response to topically applied chemical haptens. Immune modulation appears to result from selective targeting of activated T lymphocytes and reduction in immunostimulation by antigen presenting cells. Psoriasis, an immune-mediated skin condition, exhibits heightened epidermal cell proliferation, epidermal layer thickening and plaque formation at different body sites. In a recent clinical trial, approximately one-third of patients with psoriasis and arthritis symptoms (psoriatic arthritis) displayed a significant clinical improvement in several psoriasis-related parameters after four weekly whole-body PIM treatments with verteporfin. The safety profile was favorable. The capacity of PIM to influence other human immune disorders including rheumatoid arthritis is under extensive evaluation.

  9. Bed rest and immunity

    NASA Astrophysics Data System (ADS)

    Sonnenfeld, Gerald; Aviles, Hernan; Butel, Janet S.; Shearer, William T.; Niesel, David; Pandya, Utpal; Allen, Christopher; Ochs, Hans D.; Blancher, Antoine; Abbal, Michel

    2007-02-01

    Space flight has been shown to result in altered immune responses. The current study was designed to investigate this possibility by using the bed rest model of some space flight conditions. A large number of women are included as subjects in the study. The hypothesis being tested is: 60 days head-down tilt bed rest of humans will affect the immune system and resistance to infection. Blood, urine and saliva samples will be obtained from bed rest subjects prior to, at intervals during, and after completion of 60 days of head-down tilt bed rest. Leukocyte blastogenesis, cytokine production and virus reactivation will be assessed. The ability of the subjects to respond appropriately to immunization with the neoantigen bacteriophage φX-174 will also be determined. Bed rest is being carried out at MEDES, Toulouse France, and the University of Texas Medical Branch, Galveston, TX. The studies to be carried out in France will also allow assessment of the effects of muscle/bone exercise and nutritional countermeasures on the immune system in addition to the effects of bed rest.

  10. Immune Deficiency Foundation

    MedlinePlus

    ... for IDF Join our nationwide network of volunteers Resources For Patients & Families Peer Support Speak with someone who understands Locate a Physician ... secure Legacy Giving Establish your personal legacy and support IDF 'Immune Deficiency Foundation Remembers' Plaque Pay tribute to ... Educational Resources Find a wealth of IDF educational publications and ...

  11. Increasing Immunization Compliance

    ERIC Educational Resources Information Center

    Toole, Kimberly; Perry, Cynthia S.

    2004-01-01

    School nurses often have the responsibility to ensure that students meet all immunization requirements for school entry and school attendance. In large inner-city school districts, many obstacles exist which make this task daunting and often result in lengthy absences and exclusions for students. It is critical that school nurses find creative and…

  12. Synthetic plant defense elicitors

    PubMed Central

    Bektas, Yasemin; Eulgem, Thomas

    2015-01-01

    To defend themselves against invading pathogens plants utilize a complex regulatory network that coordinates extensive transcriptional and metabolic reprogramming. Although many of the key players of this immunity-associated network are known, the details of its topology and dynamics are still poorly understood. As an alternative to forward and reverse genetic studies, chemical genetics-related approaches based on bioactive small molecules have gained substantial popularity in the analysis of biological pathways and networks. Use of such molecular probes can allow researchers to access biological space that was previously inaccessible to genetic analyses due to gene redundancy or lethality of mutations. Synthetic elicitors are small drug-like molecules that induce plant defense responses, but are distinct from known natural elicitors of plant immunity. While the discovery of some synthetic elicitors had already been reported in the 1970s, recent breakthroughs in combinatorial chemical synthesis now allow for inexpensive high-throughput screens for bioactive plant defense-inducing compounds. Along with powerful reverse genetics tools and resources available for model plants and crop systems, comprehensive collections of new synthetic elicitors will likely allow plant scientists to study the intricacies of plant defense signaling pathways and networks in an unparalleled fashion. As synthetic elicitors can protect crops from diseases, without the need to be directly toxic for pathogenic organisms, they may also serve as promising alternatives to conventional biocidal pesticides, which often are harmful for the environment, farmers and consumers. Here we are discussing various types of synthetic elicitors that have been used for studies on the plant immune system, their modes-of-action as well as their application in crop protection. PMID:25674095

  13. Maternal immune transfer in mollusc.

    PubMed

    Wang, Lingling; Yue, Feng; Song, Xiaorui; Song, Linsheng

    2015-02-01

    Maternal immunity refers to the immunity transferred from mother to offspring via egg, playing an important role in protecting the offspring at early life stages and contributing a trans-generational effect on offspring's phenotype. Because fertilization is external in most of the molluscs, oocytes and early embryos are directly exposed to pathogens in the seawater, and thus maternal immunity could provide a better protection before full maturation of their immunological systems. Several innate immune factors including pattern recognition receptors (PRRs) like lectins, and immune effectors like lysozyme, lipopolysaccharide binding protein/bacterial permeability-increasing proteins (LBP/BPI) and antioxidant enzymes have been identified as maternally derived immune factors in mollusc eggs. Among these immune factors, some maternally derived lectins and antibacterial factors have been proved to endue mollusc eggs with effective defense ability against pathogen infection, while the roles of other factors still remain untested. The physiological condition of mollusc broodstock has a profound effect on their offspring fitness. Many other factors such as nutrients, pathogens, environment conditions and pollutants could exert considerable influence on the maternal transfer of immunity. The parent molluscs which have encountered an immune stimulation endow their offspring with a trans-generational immune capability to protect them against infections effectively. The knowledge on maternal transfer of immunity and the trans-generational immune effect could provide us with an ideal management strategy of mollusc broodstock to improve the immunity of offspring and to establish a disease-resistant family for a long-term improvement of cultured stocks.

  14. Evolutionary responses of innate Immunity to adaptive immunity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Innate immunity is present in all metazoans, whereas the evolutionarily more novel adaptive immunity is limited to jawed fishes and their descendants (gnathostomes). We observe that the organisms that possess adaptive immunity lack diversity in their innate pattern recognition receptors (PRRs), rais...

  15. Carbohydrate-based immune adjuvants

    PubMed Central

    Petrovsky, Nikolai; Cooper, Peter D

    2011-01-01

    The role for adjuvants in human vaccines has been a matter of vigorous scientific debate, with the field hindered by the fact that for over 80 years, aluminum salts were the only adjuvants approved for human use. To this day, alum-based adjuvants, alone or combined with additional immune activators, remain the only adjuvants approved for use in the USA. This situation has not been helped by the fact that the mechanism of action of most adjuvants has been poorly understood. A relative lack of resources and funding for adjuvant development has only helped to maintain alum’s relative monopoly. To seriously challenge alum’s supremacy a new adjuvant has many major hurdles to overcome, not least being alum’s simplicity, tolerability, safety record and minimal cost. Carbohydrate structures play critical roles in immune system function and carbohydrates also have the virtue of a strong safety and tolerability record. A number of carbohydrate compounds from plant, bacterial, yeast and synthetic sources have emerged as promising vaccine adjuvant candidates. Carbohydrates are readily biodegradable and therefore unlikely to cause problems of long-term tissue deposits seen with alum adjuvants. Above all, the Holy Grail of human adjuvant development is to identify a compound that combines potent vaccine enhancement with maximum tolerability and safety. This has proved to be a tough challenge for many adjuvant contenders. Nevertheless, carbohydrate-based compounds have many favorable properties that could place them in a unique position to challenge alum’s monopoly over human vaccine usage. PMID:21506649

  16. Technique Selectively Represses Immune System

    MedlinePlus

    ... Research Matters December 3, 2012 Technique Selectively Represses Immune System Myelin (green) encases and protects nerve fibers (brown). A new technique prevents the immune system from attacking myelin in a mouse model of ...

  17. Hormone activities and the cell cycle machinery in immunity-triggered growth inhibition.

    PubMed

    Reitz, M U; Gifford, M L; Schäfer, P

    2015-04-01

    Biotic stress and diseases caused by pathogen attack pose threats in crop production and significantly reduce crop yields. Enhancing immunity against pathogens is therefore of outstanding importance in crop breeding. However, this must be balanced, as immune activation inhibits plant growth. This immunity-coupled growth trade-off does not support resistance but is postulated to reflect the reallocation of resources to drive immunity. There is, however, increasing evidence that growth-immunity trade-offs are based on the reconfiguration of hormone pathways, shared by growth and immunity signalling. Studies in roots revealed the role of hormones in orchestrating growth across different cell types, with some hormones showing a defined cell type-specific activity. This is apparently highly relevant for the regulation of the cell cycle machinery and might be part of the growth-immunity cross-talk. Since plants are constantly exposed to Immuno-activating microbes under agricultural conditions, the transition from a growth to an immunity operating mode can significantly reduce crop yield and can conflict our efforts to generate next-generation crops with improved yield under climate change conditions. By focusing on roots, we outline the current knowledge of hormone signalling on the cell cycle machinery to explain growth trade-offs induced by immunity. By referring to abiotic stress studies, we further introduce how root cell type-specific hormone activities might contribute to growth under immunity and discuss the feasibility of uncoupling the growth-immunity cross-talk.

  18. Hormone activities and the cell cycle machinery in immunity-triggered growth inhibition

    PubMed Central

    Reitz, M. U.; Gifford, M. L.; Schäfer, P.

    2015-01-01

    Biotic stress and diseases caused by pathogen attack pose threats in crop production and significantly reduce crop yields. Enhancing immunity against pathogens is therefore of outstanding importance in crop breeding. However, this must be balanced, as immune activation inhibits plant growth. This immunity-coupled growth trade-off does not support resistance but is postulated to reflect the reallocation of resources to drive immunity. There is, however, increasing evidence that growth–immunity trade-offs are based on the reconfiguration of hormone pathways, shared by growth and immunity signalling. Studies in roots revealed the role of hormones in orchestrating growth across different cell types, with some hormones showing a defined cell type-specific activity. This is apparently highly relevant for the regulation of the cell cycle machinery and might be part of the growth–immunity cross-talk. Since plants are constantly exposed to Immuno-activating microbes under agricultural conditions, the transition from a growth to an immunity operating mode can significantly reduce crop yield and can conflict our efforts to generate next-generation crops with improved yield under climate change conditions. By focusing on roots, we outline the current knowledge of hormone signalling on the cell cycle machinery to explain growth trade-offs induced by immunity. By referring to abiotic stress studies, we further introduce how root cell type-specific hormone activities might contribute to growth under immunity and discuss the feasibility of uncoupling the growth–immunity cross-talk. PMID:25821072

  19. Climate change, nutrition and immunity: Effects of elevated CO2 and temperature on the immune function of an insect herbivore.

    PubMed

    Gherlenda, Andrew N; Haigh, Anthony M; Moore, Ben D; Johnson, Scott N; Riegler, Markus

    2016-02-01

    Balanced nutrition is fundamental to health and immunity. For herbivorous insects, nutrient-compositional shifts in host plants due to elevated atmospheric CO2 concentrations and temperature may compromise this balance. Therefore, understanding their immune responses to such shifts is vital if we are to predict the outcomes of climate change for plant-herbivore-parasitoid and pathogen interactions. We tested the immune response of Paropsis atomaria Olivier (Coleoptera: Chrysomelidae) feeding on Eucalyptus tereticornis Sm. seedlings exposed to elevated CO2 (640 μmol mol(-1); CE) and temperature (ambient plus 4 °C; TE). Larvae were immune-challenged with a nylon monofilament in order to simulate parasitoid or pathogen attack without other effects of actual parasitism or pathology. The cellular (in vivo melanisation) and humoral (in vitro phenoloxidase PO activity) immune responses were assessed, and linked to changes in leaf chemistry. CE reduced foliar nitrogen (N) concentrations and increased C:N ratios and concentrations of total phenolics. The humoral response was reduced at CE. PO activity and haemolymph protein concentrations decreased at CE, while haemolymph protein concentrations were positively correlated with foliar N concentrations. However, the cellular response increased at CE and this was not correlated with any foliar traits. Immune parameters were not impacted by TE. Our study revealed that opposite cellular and humoral immune responses occurred as a result of plant-mediated effects at CE. In contrast, elevated temperatures within the tested range had minimal impact on immune responses. These complex interactions may alter the outcomes of parasitoid and pathogen attack in future climates. PMID:26678330

  20. Climate change, nutrition and immunity: Effects of elevated CO2 and temperature on the immune function of an insect herbivore.

    PubMed

    Gherlenda, Andrew N; Haigh, Anthony M; Moore, Ben D; Johnson, Scott N; Riegler, Markus

    2016-02-01

    Balanced nutrition is fundamental to health and immunity. For herbivorous insects, nutrient-compositional shifts in host plants due to elevated atmospheric CO2 concentrations and temperature may compromise this balance. Therefore, understanding their immune responses to such shifts is vital if we are to predict the outcomes of climate change for plant-herbivore-parasitoid and pathogen interactions. We tested the immune response of Paropsis atomaria Olivier (Coleoptera: Chrysomelidae) feeding on Eucalyptus tereticornis Sm. seedlings exposed to elevated CO2 (640 μmol mol(-1); CE) and temperature (ambient plus 4 °C; TE). Larvae were immune-challenged with a nylon monofilament in order to simulate parasitoid or pathogen attack without other effects of actual parasitism or pathology. The cellular (in vivo melanisation) and humoral (in vitro phenoloxidase PO activity) immune responses were assessed, and linked to changes in leaf chemistry. CE reduced foliar nitrogen (N) concentrations and increased C:N ratios and concentrations of total phenolics. The humoral response was reduced at CE. PO activity and haemolymph protein concentrations decreased at CE, while haemolymph protein concentrations were positively correlated with foliar N concentrations. However, the cellular response increased at CE and this was not correlated with any foliar traits. Immune parameters were not impacted by TE. Our study revealed that opposite cellular and humoral immune responses occurred as a result of plant-mediated effects at CE. In contrast, elevated temperatures within the tested range had minimal impact on immune responses. These complex interactions may alter the outcomes of parasitoid and pathogen attack in future climates.

  1. miRNA-124 in Immune System and Immune Disorders

    PubMed Central

    Qin, Zhen; Wang, Peng-Yuan; Su, Ding-Feng; Liu, Xia

    2016-01-01

    In recent years, miR-124 has emerged as a critical modulator of immunity and inflammation. Here, we summarize studies on the function and mechanism of miR-124 in the immune system and immunity-related diseases. They indicated that miR-124 exerts a crucial role in the development of immune system, regulation of immune responses, and inflammatory disorders. It is evident that miR-124 may serve as an informative diagnostic biomarker and therapeutic target in the future. PMID:27757114

  2. Intravenous Rh immune globulin for treating immune thrombocytopenic purpura.

    PubMed

    Sandler, S G

    2001-11-01

    Intravenous Rh [corrected] immune globulin was licensed by the U. S. Food and Drug administration in 1995 for the treatment of acute and chronic immune thrombocytopenic purpura in children and chronic immune thrombocytopenic purpura in adults. In 1996, the American Society of Hematology published a practice guideline for immune thrombocytopenic purpura, but treatment recommendations of necessity were formulated using only results of early clinical trials with intravenous Rh immune globulin. To date, there are no published results of large-scale clinical trials comparing conventional doses of intravenous immune globulin with the most promising dose range for intravenous Rh immune globulin (50-75 microg/kg). However, clinical experience is accumulating to indicate that intravenous Rh immune globulin is as effective, probably safer, and easier to administer than intravenous immune globulin. Acute intravascular hemolysis after infusions of intravenous Rh immune globulin for immune thrombocytopenic purpura has been reported with an estimated incidence of 1 in 1,115 patients. The risk factors for this adverse event have not been defined.

  3. Recombinant lentivector as a genetic immunization vehicle for antitumor immunity

    PubMed Central

    He, Yukai; Munn, David; Falo, Louis D

    2011-01-01

    Summary Encouraged by remarkable successes in preventing infectious diseases and by the well established potential of immune system for controlling tumor growth, active therapeutic immunization approaches hold great promise for treating malignant tumors. In recent years, engineered recombinant viral vectors have been carefully examined as genetic immunization vehicles and have been demonstrated to induce potent T cell mediated immune responses that can control tumor growth. Very recent efforts suggest that lentivectors possess important advantages over other candidate recombinant viral vectors for genetic immunization. Here we review the development of recombinant lentivectors and the characteristics of T cell immune responses elicited by lentivector immunization, including the mechanism of T cell priming with a focus on the role of skin dendritic cells (DC) and potential applications for tumor immunotherapy. PMID:18377355

  4. Plant pattern-recognition receptors.

    PubMed

    Zipfel, Cyril

    2014-07-01

    Plants are constantly exposed to would-be pathogens in their immediate environment. Yet, despite relying on innate immunity only, plants are resistant to most microbes. They employ pattern-recognition receptors (PRRs) for sensitive and rapid detection of the potential danger caused by microbes and pests. Plant PRRs are either surface-localized receptor kinases (RKs) or receptor-like proteins (RLPs) containing various ligand-binding ectodomains that perceive pathogen-associated molecular patterns (PAMPs) or damage-associated molecular patterns (DAMPs). In this review, I summarize our current knowledge of plant PRRs and their ligands, illustrating the multiple molecular strategies employed by plant PRRs to activate innate immune signaling to survive.

  5. Sunitinib Induced Immune Thrombocytopenia.

    PubMed

    Shekarriz, Ramin; Koulaeinejad, Neda; Nosrati, Anahita; Salehifa, Ebrahim

    2015-01-01

    Sunitinib is an oral tyrosine kinase inhibitor which prevents tumor growth and metastatic progression. It was approved for treatment of advanced renal cell cancer, gastrointestinal stromal tumor and advanced pancreatic neuroendocrine tumors. It has several adverse reactions on multi organ systems including hematologic system. Although the neutropenia and thrombocytopenia commonly happens as Grade 3 or 4 abnormalities following bone marrow suppression, in the rare cases, the immune mediated abnormality may drive the sunitinib-induced hematologic disorder. In this report, we present a case of immune-mediated thrombocytopenia induced by sunitinib. One month after first treatment cycle with sunitinib, leucopenia and thrombocytopenia were occurred. The patient had a normal bone marrow aspiration and biopsy, the thrombocytopenia was resistant to platelet transfusion which successfully was treated with prednisolone. PMID:26664400

  6. Sunitinib Induced Immune Thrombocytopenia

    PubMed Central

    Shekarriz, Ramin; Koulaeinejad, Neda; Nosrati, Anahita; Salehifa, Ebrahim

    2015-01-01

    Sunitinib is an oral tyrosine kinase inhibitor which prevents tumor growth and metastatic progression. It was approved for treatment of advanced renal cell cancer, gastrointestinal stromal tumor and advanced pancreatic neuroendocrine tumors. It has several adverse reactions on multi organ systems including hematologic system. Although the neutropenia and thrombocytopenia commonly happens as Grade 3 or 4 abnormalities following bone marrow suppression, in the rare cases, the immune mediated abnormality may drive the sunitinib-induced hematologic disorder. In this report, we present a case of immune-mediated thrombocytopenia induced by sunitinib. One month after first treatment cycle with sunitinib, leucopenia and thrombocytopenia were occurred. The patient had a normal bone marrow aspiration and biopsy, the thrombocytopenia was resistant to platelet transfusion which successfully was treated with prednisolone. PMID:26664400

  7. Toward understanding of rice innate immunity against Magnaporthe oryzae.

    PubMed

    Azizi, P; Rafii, M Y; Abdullah, S N A; Nejat, N; Maziah, M; Hanafi, M M; Latif, M A; Sahebi, M

    2016-01-01

    The blast fungus, Magnaporthe oryzae, causes serious disease on a wide variety of grasses including rice, wheat and barley. The recognition of pathogens is an amazing ability of plants including strategies for displacing virulence effectors through the adaption of both conserved and variable pathogen elicitors. The pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) and effector-triggered immunity (ETI) were reported as two main innate immune responses in plants, where PTI gives basal resistance and ETI confers durable resistance. The PTI consists of extracellular surface receptors that are able to recognize PAMPs. PAMPs detect microbial features such as fungal chitin that complete a vital function during the organism's life. In contrast, ETI is mediated by intracellular receptor molecules containing nucleotide-binding (NB) and leucine rich repeat (LRR) domains that specifically recognize effector proteins produced by the pathogen. To enhance crop resistance, understanding the host resistance mechanisms against pathogen infection strategies and having a deeper knowledge of innate immunity system are essential. This review summarizes the recent advances on the molecular mechanism of innate immunity systems of rice against M. oryzae. The discussion will be centered on the latest success reported in plant-pathogen interactions and integrated defense responses in rice.

  8. Immunity to amoeba.

    PubMed

    Nowak, Barbara; Valdenegro-Vega, Victoria; Crosbie, Philip; Bridle, Andrew

    2014-04-01

    Amoebic infections in fish are most likely underestimated and sometimes overlooked due to the challenges associated with their diagnosis. Amoebic diseases reported in fish affect either gills or internal organs or may be systemic. Host response ranges from hyperplastic response in gill infections to inflammation (including granuloma formation) in internal organs. This review focuses on the immune response of Atlantic salmon to Neoparamoeba perurans, the causative agent of Amoebic Gill Disease (AGD).

  9. Auto immune hepatitis.

    PubMed

    van Gerven, Nicole Mf; de Boer, Ynto S; Mulder, Chris Jj; van Nieuwkerk, Carin Mj; Bouma, Gerd

    2016-05-21

    To provide an update of the latest trends in epidemiology, clinical course, diagnostics, complications and treatment of auto immune hepatitis (AIH). A search of the MEDLINE database was performed using the search terms: "auto immune hepatitis", "clinical presentation", "symptoms", "signs", "diagnosis", "auto antibodies", "laboratory values", "serology", "histopathology", "histology", "genetics", "HLA genes", "non-HLA genes", "environment", "epidemiology", "prevalence", "incidence", "demographics", "complications", "HCC", "PBC", "PSC", "corticosteroid", "therapy", "treatment", "alternative treatment". English-language full-text articles and abstracts were considered. Articles included reviews, meta-analysis, prospective retrospective studies. No publication date restrictions were applied. AIH is an immune meditated progressive inflammatory liver disease that predominantly affects middle-aged females but may affect people of all ages. The clinical spectrum of AIH is wide, ranging from absent or mild symptoms to fulminant hepatic failure. The aetiology of AIH is still unknown, but is believed to occur as the consequence of an aberrant immune response towards an un-known trigger in a genetically susceptible host. In the absence of a gold standard, diagnosis is based on the combination of clinical, biochemical and histopathological criteria. Immunosuppressive treatment has been the cornerstone of treatment since the earliest description of the disease in 1950 by Waldenström. Such treatment is often successful at inducing remission and generally leads to normal life expectancy. Nevertheless, there remain significant areas of unmet aetiological a clinical needs including fundamental insight in disease pathogenesis, optimal therapy, duration of treatment and treatment alternatives in those patients unresponsive to standard treatment regimens. PMID:27217697

  10. Auto immune hepatitis

    PubMed Central

    van Gerven, Nicole MF; de Boer, Ynto S; Mulder, Chris JJ; van Nieuwkerk, Carin MJ; Bouma, Gerd

    2016-01-01

    To provide an update of the latest trends in epidemiology, clinical course, diagnostics, complications and treatment of auto immune hepatitis (AIH). A search of the MEDLINE database was performed using the search terms: “auto immune hepatitis”, “clinical presentation”, “symptoms”, “signs”, “diagnosis”, “auto antibodies”, “laboratory values”, “serology”, “histopathology”, “histology”, “genetics”, “HLA genes”, “non-HLA genes”, “environment”, “epidemiology”, “prevalence”, “incidence”, “demographics”, “complications”, “HCC”, “PBC”, “PSC”, “corticosteroid”, “therapy”, “treatment”, “alternative treatment”. English-language full-text articles and abstracts were considered. Articles included reviews, meta-analysis, prospective retrospective studies. No publication date restrictions were applied. AIH is an immune meditated progressive inflammatory liver disease that predominantly affects middle-aged females but may affect people of all ages. The clinical spectrum of AIH is wide, ranging from absent or mild symptoms to fulminant hepatic failure. The aetiology of AIH is still unknown, but is believed to occur as the consequence of an aberrant immune response towards an un-known trigger in a genetically susceptible host. In the absence of a gold standard, diagnosis is based on the combination of clinical, biochemical and histopathological criteria. Immunosuppressive treatment has been the cornerstone of treatment since the earliest description of the disease in 1950 by Waldenström. Such treatment is often successful at inducing remission and generally leads to normal life expectancy. Nevertheless, there remain significant areas of unmet aetiological a clinical needs including fundamental insight in disease pathogenesis, optimal therapy, duration of treatment and treatment alternatives in those patients unresponsive to standard treatment regimens. PMID:27217697

  11. Why parents refuse immunization?

    PubMed

    Kajetanowicz, Andrzej; Kajetanowicz, Aleksandra

    2016-01-01

    Rates of child immunization are falling in many countries, leading to the increase of morbidity and mortality from diseases controlled by vaccinations. The simplified model of the natural history of immunization follows a sequence of fear of the disease before vaccination, followed by acceptance of the vaccination until plateau, where the population forgets the morbidity and mortality of pre-immunization. Historical factors including withdrawals of vaccines, and publications regarding the true or falsified dangers of vaccines still resonate with parents. Building on these historical factors, unscientific sources such as naturopaths, homeopaths, chiropractors, celebrities and lay-people with anecdotal evidence and even scientific sources such as some universities and some medical doctors push their views on anti-vaccination, which proves to make the decision to vaccinate more difficult on parents. The main reason that parents refuse vaccination is a desire to protect their children. These parents believe that vaccination is harmful, or that not vaccinated children are healthier than vaccinated children. Scientific data often will lose with pseudoscientific, false or anecdotal data that have higher sensational and emotional impact on parents. With so many sources giving so many factors which sometimes contradict themselves, it is indeed difficult for a parent to make a clear decision for their child. PMID:27486715

  12. Bateman's principle and immunity.

    PubMed Central

    Rolff, Jens

    2002-01-01

    The immunocompetence handicap hypothesis (ICHH) of Folstad and Karter has inspired a large number of studies that have tried to understand the causal basis of parasite-mediated sexual selection. Even though this hypothesis is based on the double function of testosterone, a hormone restricted to vertebrates, studies of invertebrates have tended to provide central support for specific predictions of the ICHH. I propose an alternative hypothesis that explains many of the findings without relying on testosterone or other biochemical feedback loops. This alternative is based on Bateman's principle, that males gain fitness by increasing their mating success whilst females increase fitness through longevity because their reproductive effort is much higher. Consequently, I predict that females should invest more in immunity than males. The extent of this dimorphism is determined by the mating system and the genetic correlation between males and females in immune traits. In support of my arguments, I mainly use studies on insects that share innate immunity with vertebrates and have the advantage that they are easier to study. PMID:11958720

  13. Immune function in PTSD.

    PubMed

    Altemus, Margaret; Dhabhar, Firdaus S; Yang, Ruirong

    2006-07-01

    Disturbed regulation of both the hypothalamic-pituitary-adrenal (HPA) axis and sympathoadrenomedullary system in posttraumatic stress disorder (PTSD) suggests that immune function, which is modulated by these systems, may also be dysregulated. Two dermatologic, in vivo measures of immune function, delayed-type hypersensitivity (DTH) and skin barrier function recovery, were examined in female subjects with PTSD and compared to measures in healthy female comparison subjects. In addition, at the time of DTH test placement, circulating numbers of lymphocyte subtypes were assessed. In separate studies, the effects of acute psychological stress on DTH and skin barrier function recovery were examined in healthy volunteer subjects. Both DTH and barrier function recovery were enhanced in women with PTSD. These findings contrast with the effects of acute stress in healthy control subjects, which was associated with suppression of DTH responses and skin barrier function recovery. There was no difference between subjects with PTSD and healthy control subjects in proportions of circulating lymphocyte subsets or in expression of the lymphocyte markers CD62, CD25, and CD45RO/CD45RA. These results suggest that cell-mediated immune function is enhanced in individuals with PTSD, a condition that imposes chronic physiologic and mental stress on sufferers. These findings contrast with suppression of DTH and skin barrier function recovery in healthy volunteers in response to acute psychological stress.

  14. Cystatins in immune system.

    PubMed

    Magister, Spela; Kos, Janko

    2013-01-01

    Cystatins comprise a large superfamily of related proteins with diverse biological activities. They were initially characterised as inhibitors of lysosomal cysteine proteases, however, in recent years some alternative functions for cystatins have been proposed. Cystatins possessing inhibitory function are members of three families, family I (stefins), family II (cystatins) and family III (kininogens). Stefin A is often linked to neoplastic changes in epithelium while another family I cystatin, stefin B is supposed to have a specific role in neuredegenerative diseases. Cystatin C, a typical type II cystatin, is expressed in a variety of human tissues and cells. On the other hand, expression of other type II cystatins is more specific. Cystatin F is an endo/lysosome targeted protease inhibitor, selectively expressed in immune cells, suggesting its role in processes related to immune response. Our recent work points on its role in regulation of dendritic cell maturation and in natural killer cells functional inactivation that may enhance tumor survival. Cystatin E/M expression is mainly restricted to the epithelia of the skin which emphasizes its prominent role in cutaneous biology. Here, we review the current knowledge on type I (stefins A and B) and type II cystatins (cystatins C, F and E/M) in pathologies, with particular emphasis on their suppressive vs. promotional function in the tumorigenesis and metastasis. We proposed that an imbalance between cathepsins and cystatins may attenuate immune cell functions and facilitate tumor cell invasion.

  15. A bacterial tyrosine phosphatase inhibits plant pattern recognition receptor activation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Perception of pathogen-associated molecular patterns (PAMPs) by surface-localised pattern-recognition receptors (PRRs) is a key component of plant innate immunity. Most known plant PRRs are receptor kinases and initiation of PAMP-triggered immunity (PTI) signalling requires phosphorylation of the PR...

  16. RECONSTRUCTING IMMUNE PHYLOGENY: NEW PERSPECTIVES

    PubMed Central

    Litman, Gary W.; Cannon, John P.; Dishaw, Larry J.

    2013-01-01

    Numerous studies of the mammalian immune system have begun to uncover profound interrelationships, as well as fundamental differences, between the adaptive and innate systems of immune recognition. Coincident with these investigations, the increasing experimental accessibility of non-mammalian jawed vertebrates, jawless vertebrates, protochordates and invertebrates has provided intriguing new information regarding the likely patterns of emergence of immune-related molecules during metazoan phylogeny, as well as the evolution of alternative mechanisms for receptor diversification. Such findings blur traditional distinctions between adaptive and innate immunity and emphasize that, throughout evolution, the immune system has used a remarkably extensive variety of solutions to meet fundamentally similar requirements for host protection. PMID:16261174

  17. Immunity to influenza in ferrets

    PubMed Central

    McLaren, C.; Potter, C. W.; Jennings, R.

    1974-01-01

    The degree of immunity due to cross-reactions between antibody to influenza virus A/Hong Kong/1/68 and A/England/42/72 was studied in ferrets. Ferrets were immunized with the viruses by either live infection or by inoculation with inactivated virus vaccines. The vaccines were given with Freund's incomplete adjuvant or were given to ferrets previously infected with influenza virus A/PR/8/34. As a result of these immunizations the animals all produced similar titres of serum HI antibody to the immunizing virus, although the degree of cross-reaction with the other virus strain was variable. After immunization the animals were challenged by infection with an A/Eng/42/72-like virus and their degree of immunity was measured. It was found that the greatest immunity was in ferrets previously infected with the homologous A/Eng/42/72 virus. Animals previously infected with A/HK/68 virus also showed a measurable degree of immunity to A/Eng/42/72 infection, and this was greater than that found in animals given inactivated virus vaccines. The immunity produced by the vaccines was approximately equal, regardless of which vaccine or method of immunization was used. Thus, live infection produced a more effective, broader immunity than did the use of inactivated virus vaccines. PMID:4531448

  18. Who knows more about immunization?

    PubMed Central

    Buxton, Jane A.; McIntyre, Cheryl C.; Tu, Andrew W.; Eadie, Brennan D.; Remple, Valencia P.; Halperin, Beth; Pielak, Karen L.

    2013-01-01

    Abstract Objective To report the findings of a knowledge survey of nurse and physician immunization providers. Design Cross-sectional postal survey assessing demographic characteristics and vaccine knowledge. Setting British Columbia (BC). Participants Nurse and physician immunization providers in BC. Main outcome measures Knowledge of vaccine-preventable diseases, vaccines in general, and vaccine administration and handling practices. Results Survey responses were received from 256 nurses and 292 physicians (response rates of 48.6% and 18.3%, respectively). Most nurses (98.4%) reported receiving immunization training outside of the academic setting compared with 55.6% of physicians. Overall, nurse immunizers scored significantly higher than physician immunizers on all 3 domains of immunization knowledge (83.7% vs 72.8%, respectively; P < .001). Physicians scored highest on the vaccine-preventable disease domain and least well on the general vaccine domain. Nurses with more experience as health care providers scored higher. Physicians scored higher if they were female, served patient populations predominantly younger than 5 years, or received immunization training outside of academic settings. Conclusion In BC, nurse immunizers appear to have higher overall immunization knowledge than physicians and are more likely to receive immunization training when in practice. Physician immunizers might benefit most from further training on vaccines and vaccine administration and handling. PMID:24235210

  19. Sex Hormones and Immune Dimorphism

    PubMed Central

    Bhatia, Aruna; Sekhon, Harmandeep Kaur; Kaur, Gurpreet

    2014-01-01

    The functioning of the immune system of the body is regulated by many factors. The abnormal regulation of the immune system may result in some pathological conditions. Sex hormones of reproductive system are one of the major factors that regulate immune system due to the presence of hormone receptors on immune cells. The interaction of sex hormones and immune cells through the receptors on these cells effect the release of cytokines which determines the proliferation, differentiation, and maturation of different types of immunocytes and as a result the outcome of inflammatory or autoimmune diseases. The different regulations of sex hormones in both sexes result in immune dimorphism. In this review article the mechanism of regulation of immune system in different sexes and its impact are discussed. PMID:25478584

  20. Ocular Immune Privilege and Transplantation.

    PubMed

    Taylor, Andrew W

    2016-01-01

    Allografts are afforded a level of protection from rejection within immune-privileged tissues. Immune-privileged tissues involve mechanisms that suppress inflammation and promote immune tolerance. There are anatomical features, soluble factors, membrane-associated proteins, and alternative antigen-presenting cells (APC) that contribute to allograft survival in the immune-privileged tissue. This review presents the current understanding of how the mechanism of ocular immune privilege promotes tolerogenic activity by APC, and T cells in response to the placement of foreign antigen within the ocular microenvironment. Discussed will be the unique anatomical, cellular, and molecular mechanisms that lessen the chance for graft destroying immune responses within the eye. As more is understood about the molecular mechanisms of ocular immune privilege greater is the potential for using these molecular mechanisms in therapies to prevent allograft rejection.

  1. Insect Immunity to Entomopathogenic Fungi.

    PubMed

    Lu, H-L; St Leger, R J

    2016-01-01

    The study of infection and immunity in insects has achieved considerable prominence with the appreciation that their host defense mechanisms share many fundamental characteristics with the innate immune system of vertebrates. Studies on the highly tractable model organism Drosophila in particular have led to a detailed understanding of conserved innate immunity networks, such as Toll. However, most of these studies have used opportunistic human pathogens and may not have revealed specialized immune strategies that have arisen through evolutionary arms races with natural insect pathogens. Fungi are the commonest natural insect pathogens, and in this review, we focus on studies using Metarhizium and Beauveria spp. that have addressed immune system function and pathogen virulence via behavioral avoidance, the use of physical barriers, and the activation of local and systemic immune responses. In particular, we highlight studies on the evolutionary genetics of insect immunity and discuss insect-pathogen coevolution.

  2. Comparative immune systems in animals.

    PubMed

    Yuan, Shaochun; Tao, Xin; Huang, Shengfeng; Chen, Shangwu; Xu, Anlong

    2014-02-01

    Animal immune systems can be classified into those of innate immunity and those of adaptive immunity. It is generally thought that the former are universal for all animals and depend on germline-encoded receptors that recognize highly conserved pathogen-associated molecular patterns (PAMPs), whereas the latter are vertebrate specific and are mediated primarily by lymphocytes bearing a unique antigen receptor. However, novel adaptive or adaptive-like immunities have been found in invertebrates and jawless vertebrates, and extraordinarily complex innate immunities, created through huge expansions of many innate gene families, have recently been found in the cephalochordate amphioxus and the echinoderm sea urchin. These studies not only inspire immunologists to seek novel immune mechanisms in invertebrates but also raise questions about the origin and evolution of vertebrate immunities.

  3. Adaptation in the innate immune system and heterologous innate immunity.

    PubMed

    Martin, Stefan F

    2014-11-01

    The innate immune system recognizes deviation from homeostasis caused by infectious or non-infectious assaults. The threshold for its activation seems to be established by a calibration process that includes sensing of microbial molecular patterns from commensal bacteria and of endogenous signals. It is becoming increasingly clear that adaptive features, a hallmark of the adaptive immune system, can also be identified in the innate immune system. Such adaptations can result in the manifestation of a primed state of immune and tissue cells with a decreased activation threshold. This keeps the system poised to react quickly. Moreover, the fact that the innate immune system recognizes a wide variety of danger signals via pattern recognition receptors that often activate the same signaling pathways allows for heterologous innate immune stimulation. This implies that, for example, the innate immune response to an infection can be modified by co-infections or other innate stimuli. This "design feature" of the innate immune system has many implications for our understanding of individual susceptibility to diseases or responsiveness to therapies and vaccinations. In this article, adaptive features of the innate immune system as well as heterologous innate immunity and their implications are discussed.

  4. Addressing Immunization Registry Population Inflation in Adolescent Immunization Rates

    PubMed Central

    2015-01-01

    Objective While U.S. adolescent immunization rates are available annually at national and state levels, finding pockets of need may require county or sub-county information. Immunization information systems (IISs) are one tool for assessing local immunization rates. However, the presence of IIS records dating back to early childhood and challenges in capturing mobility out of IIS areas typically leads to denominator inflation. We examined the feasibility of weighting adolescent immunization records by length of time since last report to produce more accurate county adolescent counts and immunization rates. Methods We compared weighted and unweighted adolescent denominators from the Oregon ALERT IIS, along with county-level Census Bureau estimates, with school enrollment counts from Oregon's annual review of seventh-grade school immunization compliance for public and private schools. Adolescent immunization rates calculated using weighted data, for the state as a whole, were also checked against comparable National Immunization Survey (NIS) rates. Results Weighting individual records by the length of time since last activity substantially improved the fit of IIS data to county populations for adolescents. A nonlinear logarithmic (ogive) weight produced the best fit to the school count data of all examined estimates. Overall, the ogive weighted results matched NIS adolescent rates for Oregon. Conclusion The problem of mobility-inflated counts of teenagers can be addressed by weighting individual records based on time since last immunization. Well-populated IISs can rely on their own data to produce adolescent immunization rates and find pockets of need. PMID:25729105

  5. Fruit polyphenols, immunity and inflammation.

    PubMed

    González-Gallego, Javier; García-Mediavilla, M Victoria; Sánchez-Campos, Sonia; Tuñón, María J

    2010-10-01

    Flavonoids are a large class of naturally occurring compounds widely present in fruits, vegetables and beverages derived from plants. These molecules have been reported to possess a wide range of activities in the prevention of common diseases, including CHD, cancer, neurodegenerative diseases, gastrointestinal disorders and others. The effects appear to be related to the various biological/pharmacological activities of flavonoids. A large number of publications suggest immunomodulatory and anti-inflammatory properties of these compounds. However, almost all studies are in vitro studies with limited research on animal models and scarce data from human studies. The majority of in vitro research has been carried out with single flavonoids, generally aglycones, at rather supraphysiological concentrations. Few studies have investigated the anti-inflammatory effects of physiologically attainable flavonoid concentrations in healthy subjects, and more epidemiological studies and prospective randomised trials are still required. This review summarises evidence for the effects of fruit and tea flavonoids and their metabolites in inflammation and immunity. Mechanisms of effect are discussed, including those on enzyme function and regulation of gene and protein expression. Animal work is included, and evidence from epidemiological studies and human intervention trials is reviewed. Biological relevance and functional benefits of the reported effects, such as resistance to infection or exercise performance, are also discussed.

  6. Resin collection and social immunity in honey bees

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We determined if the use of resins, complex plant secretions with diverse antimicrobial properties, acts as a colony-level immune defense by honey bees. Colonies were enriched with extracts of Brazilian or Minnesotan propolis (a bee mixture of resins and wax) or were left as controls. We measured ge...

  7. Exercise, nutrition and immune function.

    PubMed

    Gleeson, Michael; Nieman, David C; Pedersen, Bente K

    2004-01-01

    Strenuous bouts of prolonged exercise and heavy training are associated with depressed immune cell function. Furthermore, inadequate or inappropriate nutrition can compound the negative influence of heavy exertion on immunocompetence. Dietary deficiencies of protein and specific micronutrients have long been associated with immune dysfunction. An adequate intake of iron, zinc and vitamins A, E, B6 and B12 is particularly important for the maintenance of immune function, but excess intakes of some micronutrients can also impair immune function and have other adverse effects on health. Immune system depression has also been associated with an excess intake of fat. To maintain immune function, athletes should eat a well-balanced diet sufficient to meet their energy requirements. An athlete exercising in a carbohydrate-depleted state experiences larger increases in circulating stress hormones and a greater perturbation of several immune function indices. Conversely, consuming 30-60 g carbohydrate x h(-1) during sustained intensive exercise attenuates rises in stress hormones such as cortisol and appears to limit the degree of exercise-induced immune depression. Convincing evidence that so-called 'immune-boosting' supplements, including high doses of antioxidant vitamins, glutamine, zinc, probiotics and Echinacea, prevent exercise-induced immune impairment is currently lacking. PMID:14971437

  8. Exercise, nutrition and immune function.

    PubMed

    Gleeson, Michael; Nieman, David C; Pedersen, Bente K

    2004-01-01

    Strenuous bouts of prolonged exercise and heavy training are associated with depressed immune cell function. Furthermore, inadequate or inappropriate nutrition can compound the negative influence of heavy exertion on immunocompetence. Dietary deficiencies of protein and specific micronutrients have long been associated with immune dysfunction. An adequate intake of iron, zinc and vitamins A, E, B6 and B12 is particularly important for the maintenance of immune function, but excess intakes of some micronutrients can also impair immune function and have other adverse effects on health. Immune system depression has also been associated with an excess intake of fat. To maintain immune function, athletes should eat a well-balanced diet sufficient to meet their energy requirements. An athlete exercising in a carbohydrate-depleted state experiences larger increases in circulating stress hormones and a greater perturbation of several immune function indices. Conversely, consuming 30-60 g carbohydrate x h(-1) during sustained intensive exercise attenuates rises in stress hormones such as cortisol and appears to limit the degree of exercise-induced immune depression. Convincing evidence that so-called 'immune-boosting' supplements, including high doses of antioxidant vitamins, glutamine, zinc, probiotics and Echinacea, prevent exercise-induced immune impairment is currently lacking.

  9. Apoplastic interactions between plants and plant root intruders.

    PubMed

    Mitsumasu, Kanako; Seto, Yoshiya; Yoshida, Satoko

    2015-01-01

    Numerous pathogenic or parasitic organisms attack plant roots to obtain nutrients, and the apoplast including the plant cell wall is where the plant cell meets such organisms. Root parasitic angiosperms and nematodes are two distinct types of plant root parasites but share some common features in their strategies for breaking into plant roots. Striga and Orobanche are obligate root parasitic angiosperms that cause devastating agricultural problems worldwide. Parasitic plants form an invasion organ called a haustorium, where plant cell wall degrading enzymes (PCWDEs) are highly expressed. Plant-parasitic nematodes are another type of agriculturally important plant root parasite. These nematodes breach the plant cell walls by protruding a sclerotized stylet from which PCWDEs are secreted. Responding to such parasitic invasion, host plants activate their own defense responses against parasites. Endoparasitic nematodes secrete apoplastic effectors to modulate host immune responses and to facilitate the formation of a feeding site. Apoplastic communication between hosts and parasitic plants also contributes to their interaction. Parasitic plant germination stimulants, strigolactones, are recently identified apoplastic signals that are transmitted over long distances from biosynthetic sites to functioning sites. Here, we discuss recent advances in understanding the importance of apoplastic signals and cell walls for plant-parasite interactions.

  10. Age and immunity.

    PubMed

    Vasto, Sonya; Malavolta, Marco; Pawelec, Graham

    2006-01-01

    Longitudinal studies are defining progressive alterations to the immune system associated with increased mortality in the very elderly. Many of these changes are exacerbated by or even caused by chronic T cell stimulation by persistent antigen, particularly from Cytomegalovirus. The composition of T cell subsets, their functional integrity and representation in the repertoire are all markedly influenced by age and by CMV. How these findings relate to epidemiological, functional, genetic, genomic and proteomic studies of human T cell immunosenescence was the subject of intense debate at an international conference held just before Christmas 2005 in the Black Forest.

  11. Vaccination and heterologous immunity: educating the immune system

    PubMed Central

    Gil, Anna; Kenney, Laurie L.; Mishra, Rabinarayan; Watkin, Levi B.; Aslan, Nuray; Selin, Liisa K.

    2015-01-01

    This review discusses three inter-related topics: (1) the immaturity of the neonatal and infant immune response; (2) heterologous immunity, where prior infection history with unrelated pathogens alters disease outcome resulting in either enhanced protective immunity or increased immunopathology to new infections, and (3) epidemiological human vaccine studies that demonstrate vaccines can have beneficial or detrimental effects on subsequent unrelated infections. The results from the epidemiological and heterologous immunity studies suggest that the immune system has tremendous plasticity and that each new infection or vaccine that an individual is exposed to during a lifetime will potentially alter the dynamics of their immune system. It also suggests that each new infection or vaccine that an infant receives is not only perturbing the immune system but is educating the immune system and laying down the foundation for all subsequent responses. This leads to the question, is there an optimum way to educate the immune system? Should this be taken into consideration in our vaccination protocols? PMID:25573110

  12. Pathogen Tactics to Manipulate Plant Cell Death.

    PubMed

    Mukhtar, M Shahid; McCormack, Maggie E; Argueso, Cristiana T; Pajerowska-Mukhtar, Karolina M

    2016-07-11

    Cell death is a vital process for multicellular organisms. Programmed cell death (PCD) functions in a variety of processes including growth, development, and immune responses for homeostasis maintenance. In particular, plants and animals utilize PCD to control pathogen invasion and infected cell populations. Despite some similarity, there are a number of key differences between how these organisms initiate and regulate cell death. In contrast to animals, plants are sessile, lack a circulatory system, and have additional cellular structures, including cell walls and chloroplasts. Plant cells have the autonomous ability to induce localized cell death using conserved eukaryotic pathways as well as unique plant-specific pathways. Thus, in order to successfully infect host cells, pathogens must subvert immune responses and avoid detection to prevent PCD and allow infection. Here we discuss the roles of cell death in plant immune responses and the tactics pathogens utilize to avert cell death. PMID:27404256

  13. Hypothalamic neurohormones and immune responses

    PubMed Central

    Quintanar, J. Luis; Guzmán-Soto, Irene

    2013-01-01

    The aim of this review is to provide a comprehensive examination of the current literature describing the neural-immune interactions, with emphasis on the most recent findings of the effects of neurohormones on immune system. Particularly, the role of hypothalamic hormones such as Thyrotropin-releasing hormone (TRH), Corticotropin-releasing hormone (CRH) and Gonadotropin-releasing hormone (GnRH). In the past few years, interest has been raised in extrapituitary actions of these neurohormones due to their receptors have been found in many non-pituitary tissues. Also, the receptors are present in immune cells, suggesting an autocrine or paracrine role within the immune system. In general, these neurohormones have been reported to exert immunomodulatory effects on cell proliferation, immune mediators release and cell function. The implications of these findings in understanding the network of hypothalamic neuropeptides and immune system are discussed. PMID:23964208

  14. Immune Aspects of Female Infertility

    PubMed Central

    Brazdova, Andrea; Senechal, Helene; Peltre, Gabriel; Poncet, Pascal

    2016-01-01

    Immune infertility, in terms of reproductive failure, has become a serious health issue involving approximately 1 out of 5 couples at reproductive age. Semen that is defined as a complex fluid containing sperm, cellular vesicles and other cells and components, could sensitize the female genital tract. The immune rejection of male semen in the female reproductive tract is explained as the failure of natural tolerance leading to local and/or systemic immune response. Present active immune mechanism may induce high levels of anti-seminal/sperm antibodies. It has already been proven that iso-immunization is associated with infertility. Comprehensive studies with regards to the identification of antibody-targets and the determination of specific antibody class contribute to the development of effective immuno-therapy and, on the other hand, potential immuno-contraception, and then of course to complex patient diagnosis. This review summarizes the aspects of female immune infertility. PMID:27123194

  15. Leptin Regulation of Immune Responses.

    PubMed

    Naylor, Caitlin; Petri, William A

    2016-02-01

    Leptin is a regulatory hormone with multiple roles in the immune system. We favor the concept that leptin signaling 'licenses' various immune cells to engage in immune responses and/or to differentiate. Leptin is an inflammatory molecule that is capable of activating both adaptive and innate immunity. It can also 'enhance' immune functions, including inflammatory cytokine production in macrophages, granulocyte chemotaxis, and increased Th17 proliferation. Leptin can also 'inhibit' cells; CD4(+) T cells are inhibited from differentiating into regulatory T cells in the presence of elevated leptin, while NK cells can exhibit impaired cytotoxicity under the same circumstances. Consequently, understanding the effect of leptin signaling is important to appreciate various aspects of immune dysregulation observed in malnutrition, obesity, and autoimmunity.

  16. Ocular immune privilege: a review.

    PubMed

    Koevary

    2000-12-01

    The definition of the term 'immune privilege' has evolved over the last century. Current usage refers to a state within a particular organ or tissue in which elements of normal immunity are absent. The fact that this deficiency is thought to be generally beneficial has compelled others to go a step further and venture that immune privilege acts to minimize expression of immunopathology. The purpose of this article is to review which parts of the eye hold immune privileged status, what mechanisms contribute to it, and what clinical benefits may have driven the development of these unique immune environments. The article ends with an examination of recent studies which have sought to use components of ocular immune privilege to prevent systemic autoimmune disease.

  17. Immune interactions in endometriosis.

    PubMed

    Herington, Jennifer L; Bruner-Tran, Kaylon L; Lucas, John A; Osteen, Kevin G

    2011-09-01

    Endometriosis is a common, complex gynecologic disorder characterized by the presence of endometrial glands and stroma at extrauterine (ectopic) sites. In women who develop this disease, alterations in specific biological processes involving both the endocrine and immune systems have been observed, which may explain the survival and growth of displaced endometrial tissue in affected women. In the past decade, a considerable amount of research has implicated a role for alterations in progesterone action at both eutopic and ectopic sites of endometrial growth which may contribute to the excessive inflammation associated with progression of endometriosis; however, it remains unclear whether these anomalies induce the condition or are simply a consequence of the disease process. In this article, we summarize current knowledge of alterations within the immune system of endometriosis patients and discuss how endometrial cells from women with this disease not only have the capacity to escape immunosurveillance, but also use inflammatory mechanisms to promote their growth within the peritoneal cavity. Finally, we discuss evidence that exposure to an environmental endocrine disruptor, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin, can mediate the development of an endometrial phenotype that exhibits both reduced progesterone responsiveness and hypersensitivity to proinflammatory stimuli mimicking the endometriosis phenotype. Future studies in women with endometriosis should consider whether a heightened inflammatory response within the peritoneal microenvironment contributes to the development and persistence of this disease.

  18. Chemokines and immunity

    PubMed Central

    Palomino, Diana Carolina Torres; Marti, Luciana Cavalheiro

    2015-01-01

    Chemokines are a large family of small cytokines and generally have low molecular weight ranging from 7 to 15kDa. Chemokines and their receptors are able to control the migration and residence of all immune cells. Some chemokines are considered pro-inflammatory, and their release can be induced during an immune response at a site of infection, while others are considered homeostatic and are involved in controlling of cells migration during tissue development or maintenance. The physiologic importance of this family of mediators is resulting from their specificity − members of the chemokine family induce recruitment of well-defined leukocyte subsets. There are two major chemokine sub-families based upon cysteine residues position: CXC and CC. As a general rule, members of the CXC chemokines are chemotactic for neutrophils, and CC chemokines are chemotactic for monocytes and sub-set of lymphocytes, although there are some exceptions. This review discusses the potential role of chemokines in inflammation focusing on the two best-characterized chemokines: monocyte chemoattractant protein-1, a CC chemokine, and interleukin-8, a member of the CXC chemokine sub-family. PMID:26466066

  19. The Interaction of Human Enteric Pathogens with Plants

    PubMed Central

    Lim, Jeong-A; Lee, Dong Hwan; Heu, Sunggi

    2014-01-01

    There are an increasing number of outbreaks of human pathogens related to fresh produce. Thus, the growth of human pathogens on plants should be explored. Human pathogens can survive under the harsh environments in plants, and can adhere and actively invade plants. Plant-associated microbiota or insects contribute to the survival and transmission of enteric pathogens in plants. Human enteric pathogens also trigger plant innate immunity, but some pathogens–such as Salmonella–can overcome this defense mechanism. PMID:25288993

  20. Herd Immunity: A Brief Review.

    PubMed

    Alam, M J; Rahman, M F

    2016-04-01

    Immunization is a means of protecting the greatest number of people. By reducing the number of susceptible in the community, it augments "herd immunity" making the infection more difficult to spread. It also reduces the risk for those individuals who have escaped vaccination or those who have not developed satisfactory protection. It is well to bear in mind that immunizations are not at all 100 per cent effective, particularly when an individual is exposed to a large dose of pathogenic organisms.

  1. Primary immune deficiency in bronchiectasis.

    PubMed

    Ozerovitch, Lorraine

    The primary purpose of the immune system is to protect the body from infection. Failure of the immune system can lead to repeated infections. The aim of this review is to discuss primary immune deficiency (PID) and its relationship with bronchiectasis in adults. It examines treatment options for patients with PID and provides practical details of how nurses can empower these patients to reduce their risk of respiratory infections.

  2. Primary immune deficiency in bronchiectasis.

    PubMed

    Ozerovitch, Lorraine

    The primary purpose of the immune system is to protect the body from infection. Failure of the immune system can lead to repeated infections. The aim of this review is to discuss primary immune deficiency (PID) and its relationship with bronchiectasis in adults. It examines treatment options for patients with PID and provides practical details of how nurses can empower these patients to reduce their risk of respiratory infections. PMID:27400622

  3. Skin Immunization Obviates Alcohol-Related Immune Dysfunction.

    PubMed

    Brand, Rhonda M; Stottlemyer, John Mark; Cline, Rachel A; Donahue, Cara; Behari, Jaideep; Falo, Louis D

    2015-01-01

    Alcoholics suffer from immune dysfunction that can impede vaccine efficacy. If ethanol (EtOH)-induced immune impairment is in part a result of direct exposure of immune cells to EtOH, then reduced levels of exposure could result in less immune dysfunction. As alcohol ingestion results in lower alcohol levels in skin than blood, we hypothesized that the skin immune network may be relatively preserved, enabling skin-targeted immunizations to obviate the immune inhibitory effects of alcohol consumption on conventional vaccines. We employed the two most common chronic EtOH mouse feeding models, the liver-damaging Lieber-DeCarli (LD) and liver-sparing Meadows-Cook (MC) diets, to examine the roles of EtOH and/or EtOH-induced liver dysfunction on alcohol related immunosuppression. Pair-fed mice were immunized against the model antigen ovalbumin (OVA) by DNA immunization or against flu by administering the protein-based influenza vaccine either systemically (IV, IM), directly to liver (hydrodynamic), or cutaneously (biolistic, ID). We measured resulting tissue EtOH levels, liver stress, regulatory T cell (Treg), and myeloid-derived suppressor cell (MDSC) populations. We compared immune responsiveness by measuring delayed-type hypersensitivity (DTH), antigen-specific cytotoxic T lymphocyte (CTL), and antibody induction as a function of delivery route and feeding model. We found that, as expected, and independent of the feeding model, EtOH ingestion inhibits DTH, CTL lysis, and antigen-specific total IgG induced by traditional systemic vaccines. On the other hand, skin-targeted vaccines were equally immunogenic in alcohol-exposed and non-exposed subjects, suggesting that cutaneous immunization may result in more efficacious vaccination in alcohol-ingesting subjects. PMID:26561838

  4. NOD-like receptor cooperativity in effector-triggered immunity.

    PubMed

    Griebel, Thomas; Maekawa, Takaki; Parker, Jane E

    2014-11-01

    Intracellular nucleotide-binding oligomerization domain (NOD)-like receptors (NLRs) are basic elements of innate immunity in plants and animals. Whereas animal NLRs react to conserved microbe- or damage-associated molecular patterns, plant NLRs intercept the actions of diverse pathogen virulence factors (effectors). In this review, we discuss recent genetic and molecular evidence for functional NLR pairs, and discuss the significance of NLR self-association and heteromeric NLR assemblies in the triggering of downstream signaling pathways. We highlight the versatility and impact of cooperating NLR pairs that combine pathogen sensing with the initiation of defense signaling in both plant and animal immunity. We propose that different NLR receptor molecular configurations provide opportunities for fine-tuning resistance pathways and enhancing the host's pathogen recognition spectrum to keep pace with rapidly evolving microbial populations.

  5. Ubiquitin in the immune system

    PubMed Central

    Zinngrebe, Julia; Montinaro, Antonella; Peltzer, Nieves; Walczak, Henning

    2014-01-01

    Ubiquitination is a post-translational modification process that has been implicated in the regulation of innate and adaptive immune responses. There is increasing evidence that both ubiquitination and its reversal, deubiquitination, play crucial roles not only during the development of the immune system but also in the orchestration of an immune response by ensuring the proper functioning of the different cell types that constitute the immune system. Here, we provide an overview of the latest discoveries in this field and discuss how they impact our understanding of the ubiquitin system in host defence mechanisms as well as self-tolerance. PMID:24375678

  6. Marathon training and immune function.

    PubMed

    Nieman, David C

    2007-01-01

    Many components of the immune system exhibit adverse change after marathon-type exertion. These immune changes occur in several compartments of the immune system and body (e.g. the skin, upper respiratory tract mucosal tissue, lung, peritoneal cavity, blood and muscle). Of all immune cells, natural killer (NK) cells, neutrophils and macrophages (of the innate immune system) exhibit the greatest changes in response to marathon competition, both in terms of numbers and function. Many mechanisms appear to be involved, including exercise-induced changes in stress hormone and cytokine concentrations, body temperature changes, increases in blood flow and dehydration. During this 'open window' of immune dysfunction (which may last between 3 and 72 hours, depending on the immune measure), viruses and bacteria may gain a foothold, increasing the risk of subclinical and clinical infection. Of the various nutritional and pharmacological countermeasures to marathon-induced immune perturbations that have been evaluated thus far, ingestion of carbohydrate beverages during intense and prolonged exercise has emerged as the most effective. However, carbohydrate ingestion during a marathon attenuates increases in plasma cytokines and stress hormones, but is largely ineffective against changes in other immune components including suppression of NK and T-cell function, and salivary IgA output. Other countermeasures, such as glutamine, antioxidant supplements and ibuprofen, have had disappointing results and thus the search for companion agents to carbohydrate continues. PMID:17465622

  7. Innate Immune Recognition of EBV.

    PubMed

    Lünemann, Anna; Rowe, Martin; Nadal, David

    2015-01-01

    The ability of Epstein-Barr virus (EBV) to establish latency despite specific immune responses and to successfully persist lifelong in the human host shows that EBV has developed powerful strategies and mechanisms to exploit, evade, abolish, or downsize otherwise effective immune responses to ensure its own survival. This chapter focuses on current knowledge on innate immune responses against EBV and its evasion strategies for own benefit and summarizes the questions that remain to be tackled. Innate immune reactions against EBV originate both from the main target cells of EBV and from nontarget cells, which are elements of the innate immune system. Thus, we structured our review accordingly but with a particular focus on the innate recognition of EBV in its two stages in its life cycle, latent state and lytic replication. Specifically, we discuss (I) innate sensing and resulting innate immune responses against EBV by its main target cells, focusing on (i) EBV transmission between epithelial cells and B cells and their life cycle stages; and (ii) elements of innate immunity in EBV's target cells. Further, we debate (II) the innate recognition and resulting innate immune responses against EBV by cells other than the main target cells, focusing on (iii) myeloid cells: dendritic cells, monocytes, macrophages, and neutrophil granulocytes; and (iv) natural killer cells. Finally, we address (III) how EBV counteracts or exploits innate immunity in its latent and lytic life cycle stages, concentrating on (v) TLRs; (vi) EBERs; and (vii) microRNAs. PMID:26428378

  8. Cellular immune responses to HIV

    NASA Astrophysics Data System (ADS)

    McMichael, Andrew J.; Rowland-Jones, Sarah L.

    2001-04-01

    The cellular immune response to the human immunodeficiency virus, mediated by T lymphocytes, seems strong but fails to control the infection completely. In most virus infections, T cells either eliminate the virus or suppress it indefinitely as a harmless, persisting infection. But the human immunodeficiency virus undermines this control by infecting key immune cells, thereby impairing the response of both the infected CD4+ T cells and the uninfected CD8+ T cells. The failure of the latter to function efficiently facilitates the escape of virus from immune control and the collapse of the whole immune system.

  9. Ubiquitin in the immune system.

    PubMed

    Zinngrebe, Julia; Montinaro, Antonella; Peltzer, Nieves; Walczak, Henning

    2014-01-01

    Ubiquitination is a post-translational modification process that has been implicated in the regulation of innate and adaptive immune responses. There is increasing evidence that both ubiquitination and its reversal, deubiquitination, play crucial roles not only during the development of the immune system but also in the orchestration of an immune response by ensuring the proper functioning of the different cell types that constitute the immune system. Here, we provide an overview of the latest discoveries in this field and discuss how they impact our understanding of the ubiquitin system in host defence mechanisms as well as self-tolerance.

  10. The microbiome and innate immunity.

    PubMed

    Thaiss, Christoph A; Zmora, Niv; Levy, Maayan; Elinav, Eran

    2016-07-01

    The intestinal microbiome is a signalling hub that integrates environmental inputs, such as diet, with genetic and immune signals to affect the host's metabolism, immunity and response to infection. The haematopoietic and non-haematopoietic cells of the innate immune system are located strategically at the host-microbiome interface. These cells have the ability to sense microorganisms or their metabolic products and to translate the signals into host physiological responses and the regulation of microbial ecology. Aberrations in the communication between the innate immune system and the gut microbiota might contribute to complex diseases. PMID:27383981

  11. Ensuring excellence in immunization services.

    PubMed

    MacDonald, Pauline

    2016-01-01

    In order to increase uptake of measles, mumps and rubella (MMR) vaccine, a domiciliary immunization service was established in Dudley primary care trust in England in 2010. Parents of unimmunized children were offered vaccines at home. Uptake of MMR vaccine among 2 year olds rose from 89% in 2007/08 to 96.9% in 2015. Children were also given any other outstanding immunizations. The domiciliary immunization service reached vulnerable unimmunized children who may otherwise have remained unprotected against life threatening childhood illnesses. Domiciliary immunization service was set up in 2010 to reduce inequalities in uptake of MMR vaccine among children aged between 2 and 5 years. PMID:26618244

  12. Ubiquitin signaling in immune responses

    PubMed Central

    Hu, Hongbo; Sun, Shao-Cong

    2016-01-01

    Ubiquitination has emerged as a crucial mechanism that regulates signal transduction in diverse biological processes, including different aspects of immune functions. Ubiquitination regulates pattern-recognition receptor signaling that mediates both innate immune responses and dendritic cell maturation required for initiation of adaptive immune responses. Ubiquitination also regulates the development, activation, and differentiation of T cells, thereby maintaining efficient adaptive immune responses to pathogens and immunological tolerance to self-tissues. Like phosphorylation, ubiquitination is a reversible reaction tightly controlled by the opposing actions of ubiquitin ligases and deubiquitinases. Deregulated ubiquitination events are associated with immunological disorders, including autoimmune and inflammatory diseases. PMID:27012466

  13. The microbiome and innate immunity.

    PubMed

    Thaiss, Christoph A; Zmora, Niv; Levy, Maayan; Elinav, Eran

    2016-07-06

    The intestinal microbiome is a signalling hub that integrates environmental inputs, such as diet, with genetic and immune signals to affect the host's metabolism, immunity and response to infection. The haematopoietic and non-haematopoietic cells of the innate immune system are located strategically at the host-microbiome interface. These cells have the ability to sense microorganisms or their metabolic products and to translate the signals into host physiological responses and the regulation of microbial ecology. Aberrations in the communication between the innate immune system and the gut microbiota might contribute to complex diseases.

  14. Apoplastic interactions between plants and plant root intruders

    PubMed Central

    Mitsumasu, Kanako; Seto, Yoshiya; Yoshida, Satoko

    2015-01-01

    Numerous pathogenic or parasitic organisms attack plant roots to obtain nutrients, and the apoplast including the plant cell wall is where the plant cell meets such organisms. Root parasitic angiosperms and nematodes are two distinct types of plant root parasites but share some common features in their strategies for breaking into plant roots. Striga and Orobanche are obligate root parasitic angiosperms that cause devastating agricultural problems worldwide. Parasitic plants form an invasion organ called a haustorium, where plant cell wall degrading enzymes (PCWDEs) are highly expressed. Plant-parasitic nematodes are another type of agriculturally important plant root parasite. These nematodes breach the plant cell walls by protruding a sclerotized stylet from which PCWDEs are secreted. Responding to such parasitic invasion, host plants activate their own defense responses against parasites. Endoparasitic nematodes secrete apoplastic effectors to modulate host immune responses and to facilitate the formation of a feeding site. Apoplastic communication between hosts and parasitic plants also contributes to their interaction. Parasitic plant germination stimulants, strigolactones, are recently identified apoplastic signals that are transmitted over long distances from biosynthetic sites to functioning sites. Here, we discuss recent advances in understanding the importance of apoplastic signals and cell walls for plant–parasite interactions. PMID:26322059

  15. Oral immune therapy: targeting the systemic immune system via the gut immune system for the treatment of inflammatory bowel disease.

    PubMed

    Ilan, Yaron

    2016-01-01

    Inflammatory bowel diseases (IBD) are associated with an altered systemic immune response leading to inflammation-mediated damage to the gut and other organs. Oral immune therapy is a method of systemic immune modulation via alteration of the gut immune system. It uses the inherit ability of the innate system of the gut to redirect the systemic innate and adaptive immune responses. Oral immune therapy is an attractive clinical approach to treat autoimmune and inflammatory disorders. It can induce immune modulation without immune suppression, has minimal toxicity and is easily administered. Targeting the systemic immune system via the gut immune system can serve as an attractive novel therapeutic method for IBD. This review summarizes the current data and discusses several examples of oral immune therapeutic methods for using the gut immune system to generate signals to reset systemic immunity as a treatment for IBD.

  16. Oral immune therapy: targeting the systemic immune system via the gut immune system for the treatment of inflammatory bowel disease

    PubMed Central

    Ilan, Yaron

    2016-01-01

    Inflammatory bowel diseases (IBD) are associated with an altered systemic immune response leading to inflammation-mediated damage to the gut and other organs. Oral immune therapy is a method of systemic immune modulation via alteration of the gut immune system. It uses the inherit ability of the innate system of the gut to redirect the systemic innate and adaptive immune responses. Oral immune therapy is an attractive clinical approach to treat autoimmune and inflammatory disorders. It can induce immune modulation without immune suppression, has minimal toxicity and is easily administered. Targeting the systemic immune system via the gut immune system can serve as an attractive novel therapeutic method for IBD. This review summarizes the current data and discusses several examples of oral immune therapeutic methods for using the gut immune system to generate signals to reset systemic immunity as a treatment for IBD. PMID:26900473

  17. Occurrence of glucocorticoids discharged from a sewage treatment plant in Japan and the effects of clobetasol propionate exposure on the immune responses of common carp (Cyprinus carpio) to bacterial infection.

    PubMed

    Nakayama, Kei; Sato, Kentaro; Shibano, Takazumi; Isobe, Tomohiko; Suzuki, Go; Kitamura, Shin-Ichi

    2016-04-01

    The present study evaluated the environmental risks to common carp (Cyprinus carpio) posed by glucocorticoids present in sewage treatment plant (STP) effluent. To gather information on the seasonal variations in glucocorticoid concentration, the authors sampled the effluent of a Japanese STP every other week for 12 mo. Six of 9 selected glucocorticoids were detected in the effluent, with clobetasol propionate and betamethasone 17-valerate detected at the highest concentrations and frequencies. The present study's results indicated that effluent glucocorticoid concentration may depend on water temperature, which is closely related to the removal efficiency of the STP or to seasonal variations in the public's use of glucocorticoids. In a separate experiment, to clarify whether glucocorticoids in environmental water increase susceptibility to bacterial infection in fish, the authors examined the responses to bacterial infection (Aeromonas veronii) of common carp exposed to clobetasol propionate. Clobetasol propionate exposure did not affect bacterial infection-associated mortality. In fish infected with A. veronii but not exposed to clobetasol propionate, head kidney weight and number of leukocytes in the head kidney were significantly increased (p < 0.05), whereas these effects were not observed in infected fish exposed to clobetasol. This suggests that clobetasol propionate alleviated bacterial infection-associated inflammation. Together, these results indicate that susceptibility to bacterial infection in common carp is not affected by exposure to glucocorticoids at environmentally relevant concentrations.

  18. Effects of Sodium Butyrate Treatment on Histone Modifications and the Expression of Genes Related to Epigenetic Regulatory Mechanisms and Immune Response in European Sea Bass (Dicentrarchus Labrax) Fed a Plant-Based Diet.

    PubMed

    Terova, Genciana; Díaz, Noelia; Rimoldi, Simona; Ceccotti, Chiara; Gliozheni, Emi; Piferrer, Francesc

    2016-01-01

    Bacteria that inhabit the epithelium of the animals' digestive tract provide the essential biochemical pathways for fermenting otherwise indigestible dietary fibers, leading to the production of short-chain fatty acids (SCFAs). Of the major SCFAs, butyrate has received particular attention due to its numerous positive effects on the health of the intestinal tract and peripheral tissues. The mechanisms of action of this four-carbon chain organic acid are different; many of these are related to its potent regulatory effect on gene expression since butyrate is a histone deacetylase inhibitor that play a predominant role in the epigenetic regulation of gene expression and cell function. In the present work, we investigated in the European sea bass (Dicentrarchus labrax) the effects of butyrate used as a feed additive on fish epigenetics as well as its regulatory role in mucosal protection and immune homeostasis through impact on gene expression. Seven target genes related to inflammatory response and reinforcement of the epithelial defense barrier [tnfα (tumor necrosis factor alpha) il1β, (interleukin 1beta), il-6, il-8, il-10, and muc2 (mucin 2)] and five target genes related to epigenetic modifications [dicer1(double-stranded RNA-specific endoribonuclease), ehmt2 (euchromatic histone-lysine-N-methyltransferase 2), pcgf2 (polycomb group ring finger 2), hdac11 (histone deacetylase-11), and jarid2a (jumonji)] were analyzed in fish intestine and liver. We also investigated the effect of dietary butyrate supplementation on histone acetylation, by performing an immunoblotting analysis on liver core histone extracts. Results of the eight-week-long feeding trial showed no significant differences in weight gain or SGR (specific growth rate) of sea bass that received 0.2% sodium butyrate supplementation in the diet in comparison to control fish that received a diet without Na-butyrate. Dietary butyrate led to a twofold increase in the acetylation level of histone H4 at

  19. Effects of Sodium Butyrate Treatment on Histone Modifications and the Expression of Genes Related to Epigenetic Regulatory Mechanisms and Immune Response in European Sea Bass (Dicentrarchus Labrax) Fed a Plant-Based Diet.

    PubMed

    Terova, Genciana; Díaz, Noelia; Rimoldi, Simona; Ceccotti, Chiara; Gliozheni, Emi; Piferrer, Francesc

    2016-01-01

    Bacteria that inhabit the epithelium of the animals' digestive tract provide the essential biochemical pathways for fermenting otherwise indigestible dietary fibers, leading to the production of short-chain fatty acids (SCFAs). Of the major SCFAs, butyrate has received particular attention due to its numerous positive effects on the health of the intestinal tract and peripheral tissues. The mechanisms of action of this four-carbon chain organic acid are different; many of these are related to its potent regulatory effect on gene expression since butyrate is a histone deacetylase inhibitor that play a predominant role in the epigenetic regulation of gene expression and cell function. In the present work, we investigated in the European sea bass (Dicentrarchus labrax) the effects of butyrate used as a feed additive on fish epigenetics as well as its regulatory role in mucosal protection and immune homeostasis through impact on gene expression. Seven target genes related to inflammatory response and reinforcement of the epithelial defense barrier [tnfα (tumor necrosis factor alpha) il1β, (interleukin 1beta), il-6, il-8, il-10, and muc2 (mucin 2)] and five target genes related to epigenetic modifications [dicer1(double-stranded RNA-specific endoribonuclease), ehmt2 (euchromatic histone-lysine-N-methyltransferase 2), pcgf2 (polycomb group ring finger 2), hdac11 (histone deacetylase-11), and jarid2a (jumonji)] were analyzed in fish intestine and liver. We also investigated the effect of dietary butyrate supplementation on histone acetylation, by performing an immunoblotting analysis on liver core histone extracts. Results of the eight-week-long feeding trial showed no significant differences in weight gain or SGR (specific growth rate) of sea bass that received 0.2% sodium butyrate supplementation in the diet in comparison to control fish that received a diet without Na-butyrate. Dietary butyrate led to a twofold increase in the acetylation level of histone H4 at

  20. Effects of Sodium Butyrate Treatment on Histone Modifications and the Expression of Genes Related to Epigenetic Regulatory Mechanisms and Immune Response in European Sea Bass (Dicentrarchus Labrax) Fed a Plant-Based Diet

    PubMed Central

    Díaz, Noelia; Rimoldi, Simona; Ceccotti, Chiara; Gliozheni, Emi; Piferrer, Francesc

    2016-01-01

    Bacteria that inhabit the epithelium of the animals’ digestive tract provide the essential biochemical pathways for fermenting otherwise indigestible dietary fibers, leading to the production of short-chain fatty acids (SCFAs). Of the major SCFAs, butyrate has received particular attention due to its numerous positive effects on the health of the intestinal tract and peripheral tissues. The mechanisms of action of this four-carbon chain organic acid are different; many of these are related to its potent regulatory effect on gene expression since butyrate is a histone deacetylase inhibitor that play a predominant role in the epigenetic regulation of gene expression and cell function. In the present work, we investigated in the European sea bass (Dicentrarchus labrax) the effects of butyrate used as a feed additive on fish epigenetics as well as its regulatory role in mucosal protection and immune homeostasis through impact on gene expression. Seven target genes related to inflammatory response and reinforcement of the epithelial defense barrier [tnfα (tumor necrosis factor alpha) il1β, (interleukin 1beta), il-6, il-8, il-10, and muc2 (mucin 2)] and five target genes related to epigenetic modifications [dicer1(double-stranded RNA-specific endoribonuclease), ehmt2 (euchromatic histone-lysine-N-methyltransferase 2), pcgf2 (polycomb group ring finger 2), hdac11 (histone deacetylase-11), and jarid2a (jumonji)] were analyzed in fish intestine and liver. We also investigated the effect of dietary butyrate supplementation on histone acetylation, by performing an immunoblotting analysis on liver core histone extracts. Results of the eight-week-long feeding trial showed no significant differences in weight gain or SGR (specific growth rate) of sea bass that received 0.2% sodium butyrate supplementation in the diet in comparison to control fish that received a diet without Na-butyrate. Dietary butyrate led to a twofold increase in the acetylation level of histone H4 at

  1. Nutritional support to maintain proper immune status during intense training.

    PubMed

    Gleeson, Michael

    2013-01-01

    Prolonged exercise and heavy training are associated with depressed immune function which can increase the risk of picking up minor infections. To maintain robust immunity, athletes should eat a well-balanced diet sufficient to meet their energy, carbohydrate, protein, and micronutrient requirements. Dietary deficiencies of protein and specific micronutrients have long been associated with immune dysfunction and an adequate intake of iron, zinc, and vitamins A, D, E, B6 and B12 is particularly important in the maintenance of immune function. Consuming carbohydrate during prolonged strenuous exercise attenuates rises in stress hormones and appears to limit the degree of exercise-induced immune depression. Similar effects can be seen with daily ingestion of high-dose antioxidant vitamin supplements, though concerns have been expressed that excessive antioxidant intake may impair exercise training adaptations. It is safe to say with reasonable confidence that individual amino acids, colostrum, Echinacea, and zinc are unlikely to boost immunity or reduce infection risk in athletes. The ingestion of carbohydrate during exercise and daily consumption of probiotic and plant polyphenol (e.g. quercetin)-containing supplements or foodstuffs (e.g. non-alcoholic beer) currently offer the best chance of success. This approach is likely to be most effective for individuals who are particularly prone to illness. PMID:23765353

  2. Microscale Immune Studies Laboratory.

    SciTech Connect

    Poschet, Jens Fredrich; Carroll-Portillo, Amanda; Wu, Meiye; Manginell, Ronald Paul; Herr, Amy Elizabeth; Martino, Anthony A.; Perroud, Thomas D.; Branda, Catherine; Srivastava, Nimisha; Sinclair, Michael B.; Moorman, Matthew Wallace; Apblett, Christopher Alan; Sale, Kenneth L.; James, Conrad D.; Carles, Elizabeth L.; Lidke, Diane S.; Van Benthem, Mark Hilary; Rebeil, Roberto; Kaiser, Julie; Seaman, William; Rempe, Susan; Brozik, Susan Marie; Jones, Howland D. T.; Gemperline, Paul; Throckmorton, Daniel J.; Misra, Milind; Murton, Jaclyn K.; Carson, Bryan D.; Zhang, Zhaoduo; Plimpton, Steven James; Renzi, Ronald F.; Lane, Todd W.; Ndiaye-Dulac, Elsa; Singh, Anup K.; Haaland, David Michael; Faulon, Jean-Loup Michel; Davis, Ryan W.; Ricken, James Bryce; Branda, Steven S.; Patel, Kamlesh D.; Joo, Jaewook; Kubiak, Glenn D.; Brennan, James S.; Martin, Shawn Bryan; Brasier, Allan

    2009-01-01

    The overarching goal is to develop novel technologies to elucidate molecular mechanisms of the innate immune response in host cells to pathogens such as bacteria and viruses including the mechanisms used by pathogens to subvert/suppress/obfuscate the immune response to cause their harmful effects. Innate immunity is our first line of defense against a pathogenic bacteria or virus. A comprehensive 'system-level' understanding of innate immunity pathways such as toll-like receptor (TLR) pathways is the key to deciphering mechanisms of pathogenesis and can lead to improvements in early diagnosis or developing improved therapeutics. Current methods for studying signaling focus on measurements of a limited number of components in a pathway and hence, fail to provide a systems-level understanding. We have developed a systems biology approach to decipher TLR4 pathways in macrophage cell lines in response to exposure to pathogenic bacteria and their lipopolysaccharide (LPS). Our approach integrates biological reagents, a microfluidic cell handling and analysis platform, high-resolution imaging and computational modeling to provide spatially- and temporally-resolved measurement of TLR-network components. The Integrated microfluidic platform is capable of imaging single cells to obtain dynamic translocation data as well as high-throughput acquisition of quantitative protein expression and phosphorylation information of selected cell populations. The platform consists of multiple modules such as single-cell array, cell sorter, and phosphoflow chip to provide confocal imaging, cell sorting, flow cytomtery and phosphorylation assays. The single-cell array module contains fluidic constrictions designed to trap and hold single host cells. Up to 100 single cells can be trapped and monitored for hours, enabling detailed statistically-significant measurements. The module was used to analyze translocation behavior of transcription factor NF-kB in macrophages upon activation by E

  3. Mosquito immunity against arboviruses.

    PubMed

    Sim, Shuzhen; Jupatanakul, Natapong; Dimopoulos, George

    2014-11-19

    Arthropod-borne viruses (arboviruses) pose a significant threat to global health, causing human disease with increasing geographic range and severity. The recent availability of the genome sequences of medically important mosquito species has kick-started investigations into the molecular basis of how mosquito vectors control arbovirus infection. Here, we discuss recent findings concerning the role of the mosquito immune system in antiviral defense, interactions between arboviruses and fundamental cellular processes such as apoptosis and autophagy, and arboviral suppression of mosquito defense mechanisms. This knowledge provides insights into co-evolutionary processes between vector and virus and also lays the groundwork for the development of novel arbovirus control strategies that target the mosquito vector.

  4. Plants in Their Own Behalf.

    ERIC Educational Resources Information Center

    Patrusky, Ben

    1983-01-01

    Chemical responses as active and precisely targeted as those of animal immune systems characterize the defenses plants mount against microbial/herbivoral predation and disease. Past and current research in this field is reported and discussed. Applications, such as the prediction of past outbreaks, are also discussed. (JN)

  5. Conditioning of Model Identification Task in Immune Inspired Optimizer SILO

    NASA Astrophysics Data System (ADS)

    Wojdan, K.; Swirski, K.; Warchol, M.; Maciorowski, M.

    2009-10-01

    Methods which provide good conditioning of model identification task in immune inspired, steady-state controller SILO (Stochastic Immune Layer Optimizer) are presented in this paper. These methods are implemented in a model based optimization algorithm. The first method uses a safe model to assure that gains of the process's model can be estimated. The second method is responsible for elimination of potential linear dependences between columns of observation matrix. Moreover new results from one of SILO implementation in polish power plant are presented. They confirm high efficiency of the presented solution in solving technical problems.

  6. Child Indicators: Immunization of Young Children.

    ERIC Educational Resources Information Center

    Lewit, Eugene M.; Mullahy, John

    1994-01-01

    Focuses on the immunization status of children aged 19 to 35 months. Recommended immunizations are described and contrasted with the actual status of immunization. In response to unacceptably low levels of immunization among very young children, the government is aiming at 90% immunization by the year 2000. (SLD)

  7. An Immunization Education Program for Childcare Providers

    ERIC Educational Resources Information Center

    Hayney, Mary S.; Bartell, Julie C.

    2005-01-01

    The childhood immunization schedule includes at least 17 scheduled immunizations prior to the age of 24 months. Immunization laws require childcare centers to maintain immunization records and enforce immunization standards for children who attend these centers. Childcare providers generally receive little formal education about infectious…

  8. Integrating temperature and nutrition--environmental impacts on an insect immune system.

    PubMed

    Bauerfeind, Stephanie S; Fischer, Klaus

    2014-05-01

    Globally increasing temperatures may strongly affect insect herbivore performance. In contrast to direct effects of temperature on herbivores, indirect effects mediated via thermal effects on host-plant quality are only poorly understood, despite having the potential to substantially impact the herbivores' performance. Part of this performance is the organisms' immune system which may be of pivotal importance for local survival. We here use a full-factorial design to explore the direct (larvae were reared at 17°C or 25°C) and indirect effects (host plants were reared at 17°C or 25°C) of temperature on immune function of the temperate-zone butterfly Pieris napi. At the higher rearing temperature haemocyte numbers and prophenoloxidase activity were reduced. Plant temperature, in contrast, did not affect immune competence despite clear effects on insect growth patterns. Overall, thermal and dietary impacts on the insects' immune responses were weak and trait-specific.

  9. Questions of Mind Over Immunity.

    ERIC Educational Resources Information Center

    Bower, Bruce

    1991-01-01

    Discussed is the possibility of disturbed immunity among people experiencing either clinical depression or some type of severe stress. Psychoneuroimmunology, the study of psychological treatment and its ability to shore up a person's immunity and slow the spread of infectious disease, is reviewed. (KR)

  10. Plain Talk about Childhood Immunizations.

    ERIC Educational Resources Information Center

    Alaska State Dept. of Health and Social Services, Juneau. Div. of Family and Youth Services.

    This booklet provides parents with information about immunizations and vaccine-preventable diseases, balances the benefits and risk of vaccination, and responds to inaccuracies or misinformation about immunizations and vaccine-preventable diseases. Section 1 presents a message to parents about vaccination. Section 2 offers facts about…

  11. Recommendations for Institutional Prematriculation Immunizations

    ERIC Educational Resources Information Center

    Journal of American College Health, 2006

    2006-01-01

    The "Recommendations for Institutional Prematriculation Immunizations" described in this article are provided to colleges and universities to facilitate the implementation of a comprehensive institutional prematriculation immunization policy. In response to changing epidemiology and the introduction of new vaccines, the American College Health…

  12. Medicinal plants: conception / contraception.

    PubMed

    Chaing, H S; Merino-chavez, G; Yang, L L; Wang, F N; Hafez, E S

    1994-01-01

    Researchers have conducted considerable experiments on the effectiveness and therapeutic values of Chinese herbs and parts of plants. We should not ignore the significance of natural medicine. The Chinese have been perfecting medicinal therapy based on the raw ingredients of plants/herbs and their derivatives for thousands of years. Chinese practitioners of traditional medicine prescribe medicines based on yin and yang. Traditional medicine is communicated in a verb or written form. Natural resources used in traditional medicine to treat diseases are not limited to just medicinal plants but also include animals, shell fish, and minerals. Parts of plants used in traditional medicine are leaves, stems, flowers, bark, and root. Chinese medicine is the world's oldest continuous surviving tradition. The Chinese experimented with local plants, often resulting in mild to violent reactions. This process allowed them to become familiar with poisonous plants and those that could relieve pain or successfully treat illness. Current allopathic medicines are composed of synthetic compounds copied from natural chemical derivatives, which tend to be more potent than the original compound. Some medicinal plants used to effect conception/contraception include Striga astiatica (contraceptive); Eurycoma longifolia (male virility); and a mixture of lengkuas, mengkudu masak, black pepper seeds, ginger, salt, and 2 eggs (increase libido). Women in Malaysia take jamu to preserve their body shape and to provide nutrition during pregnancy. Praneem causes local cell-mediated immunity in the uterus. Clinical trials of Praneem with or without the hCG vaccine are planned.

  13. Effector-triggered immunity blocks pathogen degradation of an immunity-associated vesicle traffic regulator in Arabidopsis.

    PubMed

    Nomura, Kinya; Mecey, Christy; Lee, Young-Nam; Imboden, Lori Alice; Chang, Jeff H; He, Sheng Yang

    2011-06-28

    Innate immunity in plants can be triggered by microbe- and pathogen-associated molecular patterns. The pathogen-associated molecular pattern-triggered immunity (PTI) is often suppressed by pathogen effectors delivered into the host cell. Plants can overcome pathogen suppression of PTI and reestablish pathogen resistance through effector-triggered immunity (ETI). An unanswered question is how plants might overcome pathogen-suppression of PTI during ETI. Findings described in this paper suggest a possible mechanism. During Pseudomonas syringae pathovar tomato (Pst) DC3000 infection of Arabidopsis, a host ADP ribosylation factor guanine nucleotide exchange factor, AtMIN7, is destabilized by the pathogen effector HopM1 through the host 26S proteasome. In this study, we discovered that AtMIN7 is required for not only PTI, consistent with the notion that Pst DC3000 degrades AtMIN7 to suppress PTI, but also ETI. The AtMIN7 level in healthy plants is low, but increases posttranscriptionally in response to activation of PTI. Whereas DC3000 infection led to degradation of AtMIN7, activation of ETI by three different effectors, AvrRpt2, AvrPphB, and HopA1, in Col-0 plants blocks the ability of Pst DC3000 to destabilize AtMIN7. Further analyses of bacterial translocation of HopM1 and AtMIN7 stability in HopM1 transgenic plants show that ETI prevents HopM1-mediated degradation of AtMIN7 inside the plant cell. Both AtMIN7 and HopM1 are localized to the trans-Golgi network/early endosome, a subcellular compartment that is not previously known to be associated with bacterial pathogenesis in plants. Thus, blocking pathogen degradation of trans-Golgi network/early endosome-associated AtMIN7 is a critical part of the ETI mechanism to counter bacterial suppression of PTI.

  14. "Herd immunity": a rough guide.

    PubMed

    Fine, Paul; Eames, Ken; Heymann, David L

    2011-04-01

    The term "herd immunity" is widely used but carries a variety of meanings. Some authors use it to describe the proportion immune among individuals in a population. Others use it with reference to a particular threshold proportion of immune individuals that should lead to a decline in incidence of infection. Still others use it to refer to a pattern of immunity that should protect a population from invasion of a new infection. A common implication of the term is that the risk of infection among susceptible individuals in a population is reduced by the presence and proximity of immune individuals (this is sometimes referred to as "indirect protection" or a "herd effect"). We provide brief historical, epidemiologic, theoretical, and pragmatic public health perspectives on this concept.

  15. Melatonin: Buffering the Immune System

    PubMed Central

    Carrillo-Vico, Antonio; Lardone, Patricia J.; Álvarez-Sánchez, Nuria; Rodríguez-Rodríguez, Ana; Guerrero, Juan M.

    2013-01-01

    Melatonin modulates a wide range of physiological functions with pleiotropic effects on the immune system. Despite the large number of reports implicating melatonin as an immunomodulatory compound, it still remains unclear how melatonin regulates immunity. While some authors argue that melatonin is an immunostimulant, many studies have also described anti-inflammatory properties. The data reviewed in this paper support the idea of melatonin as an immune buffer, acting as a stimulant under basal or immunosuppressive conditions or as an anti-inflammatory compound in the presence of exacerbated immune responses, such as acute inflammation. The clinical relevance of the multiple functions of melatonin under different immune conditions, such as infection, autoimmunity, vaccination and immunosenescence, is also reviewed. PMID:23609496

  16. Antibiotics, microbiota, and immune defense.

    PubMed

    Ubeda, Carles; Pamer, Eric G

    2012-09-01

    The gastrointestinal tract microbiota contributes to the development and differentiation of the mammalian immune system. The composition of the microbiota affects immune responses and affects susceptibility to infection by intestinal pathogens and development of allergic and inflammatory bowel diseases. Antibiotic administration, while facilitating clearance of targeted infections, also perturbs commensal microbial communities and decreases host resistance to antibiotic-resistant microbes. Here, we review recent advances that begin to define the interactions between complex intestinal microbial populations and the mammalian immune system and how this relation is perturbed by antibiotic administration. We further discuss how antibiotic-induced disruption of the microbiota and immune homeostasis can lead to disease and we review strategies to restore immune defenses during antibiotic administration.

  17. Overview of the immune system.

    PubMed

    Medina, Kay L

    2016-01-01

    The immune system is designed to execute rapid, specific, and protective responses against foreign pathogens. To protect against the potentially harmful effects of autoreactive escapees that might arise during the course of the immune response, multiple tolerance checkpoints exist in both the primary and secondary lymphoid organs. Regardless, autoantibodies targeting neural antigens exist in multiple neurologic diseases. The goal of this introductory chapter is to provide a foundation of the major principles and components of the immune system as a framework to understanding autoimmunity and autoimmune neurologic disorders. A broad overview of: (1) innate mechanisms of immunity and their contribution in demyelinating diseases; (2) B and T lymphocytes as effector arms of the adaptive immune response and their contribution to the pathophysiology of neurologic diseases; and (3) emerging therapeutic modalities for treatment of autoimmune disease is provided.

  18. Human immune responses in cryptosporidiosis

    PubMed Central

    Borad, Anoli; Ward, Honorine

    2010-01-01

    Immune responses play a critical role in protection from, and resolution of, cryptosporidiosis. However, the nature of these responses, particularly in humans, is not completely understood. Both innate and adaptive immune responses are important. Innate immune responses may be mediated by Toll-like receptor pathways, antimicrobial peptides, prostaglandins, mannose-binding lectin, cytokines and chemokines. Cell-mediated responses, particularly those involving CD4+ T cells and IFN-γ play a dominant role. Mucosal antibody responses may also be involved. Proteins mediating attachment and invasion may serve as putative protective antigens. Further knowledge of human immune responses in cryptosporidiosis is essential in order to develop targeted prophylactic and therapeutic interventions. This review focuses on recent advances and future prospects in the understanding of human immune responses to Cryptosporidium infection. PMID:20210556

  19. Immune Mechanisms in Myelodysplastic Syndrome

    PubMed Central

    Glenthøj, Andreas; Ørskov, Andreas Due; Hansen, Jakob Werner; Hadrup, Sine Reker; O’Connell, Casey; Grønbæk, Kirsten

    2016-01-01

    Myelodysplastic syndrome (MDS) is a spectrum of diseases, characterized by debilitating cytopenias and a propensity of developing acute myeloid leukemia. Comprehensive sequencing efforts have revealed a range of mutations characteristic, but not specific, of MDS. Epidemiologically, autoimmune diseases are common in patients with MDS, fueling hypotheses of common etiological mechanisms. Both innate and adaptive immune pathways are overly active in the hematopoietic niche of MDS. Although supportive care, growth factors, and hypomethylating agents are the mainstay of MDS treatment, some patients—especially younger low-risk patients with HLA-DR15 tissue type—demonstrate impressive response rates after immunosuppressive therapy. This is in contrast to higher-risk MDS patients, where several immune activating treatments, such as immune checkpoint inhibitors, are in the pipeline. Thus, the dual role of immune mechanisms in MDS is challenging, and rigorous translational studies are needed to establish the value of immune manipulation as a treatment of MDS. PMID:27314337

  20. Immune Mechanisms in Myelodysplastic Syndrome.

    PubMed

    Glenthøj, Andreas; Ørskov, Andreas Due; Hansen, Jakob Werner; Hadrup, Sine Reker; O'Connell, Casey; Grønbæk, Kirsten

    2016-01-01

    Myelodysplastic syndrome (MDS) is a spectrum of diseases, characterized by debilitating cytopenias and a propensity of developing acute myeloid leukemia. Comprehensive sequencing efforts have revealed a range of mutations characteristic, but not specific, of MDS. Epidemiologically, autoimmune diseases are common in patients with MDS, fueling hypotheses of common etiological mechanisms. Both innate and adaptive immune pathways are overly active in the hematopoietic niche of MDS. Although supportive care, growth factors, and hypomethylating agents are the mainstay of MDS treatment, some patients-especially younger low-risk patients with HLA-DR15 tissue type-demonstrate impressive response rates after immunosuppressive therapy. This is in contrast to higher-risk MDS patients, where several immune activating treatments, such as immune checkpoint inhibitors, are in the pipeline. Thus, the dual role of immune mechanisms in MDS is challenging, and rigorous translational studies are needed to establish the value of immune manipulation as a treatment of MDS. PMID:27314337

  1. Integrated Systems View on Networking by Hormones in Arabidopsis Immunity Reveals Multiple Crosstalk for Cytokinin[W

    PubMed Central

    Naseem, Muhammad; Philippi, Nicole; Hussain, Anwar; Wangorsch, Gaby; Ahmed, Nazeer; Dandekar, Thomas

    2012-01-01

    Phytohormones signal and combine to maintain the physiological equilibrium in the plant. Pathogens enhance host susceptibility by modulating the hormonal balance of the plant cell. Unlike other plant hormones, the detailed role of cytokinin in plant immunity remains to be fully elucidated. Here, extensive data mining, including of pathogenicity factors, host regulatory proteins, enzymes of hormone biosynthesis, and signaling components, established an integrated signaling network of 105 nodes and 163 edges. Dynamic modeling and system analysis identified multiple cytokinin-mediated regulatory interactions in plant disease networks. This includes specific synergism between cytokinin and salicylic acid pathways and previously undiscovered aspects of antagonism between cytokinin and auxin in plant immunity. Predicted interactions and hormonal effects on plant immunity are confirmed in subsequent experiments with Pseudomonas syringae pv tomato DC3000 and Arabidopsis thaliana. Our dynamic simulation is instrumental in predicting system effects of individual components in complex hormone disease networks and synergism or antagonism between pathways. PMID:22643121

  2. Immune Response of Amebiasis and Immune Evasion by Entamoeba histolytica

    PubMed Central

    Nakada-Tsukui, Kumiko; Nozaki, Tomoyoshi

    2016-01-01

    Entamoeba histolytica is a protozoan parasite and the causative agent of amebiasis. It is estimated approximately 1% of humans are infected with E. histolytica, resulting in an estimate of 100,000 deaths annually. Clinical manifestations of amebic infection range widely from asymptomatic to severe symptoms, including dysentery and extra-intestinal abscesses. Like other infectious diseases, it is assumed that only ~20% of infected individuals develop symptoms, and genetic factors of both the parasite and humans as well as the environmental factors, e.g., microbiota, determine outcome of infection. There are multiple essential steps in amebic infection: degradation of and invasion into the mucosal layer, adherence to the intestinal epithelium, invasion into the tissues, and dissemination to other organs. While the mechanisms of invasion and destruction of the host tissues by the amebae during infection have been elucidated at the molecular levels, it remains largely uncharacterized how the parasite survive in the host by evading and attacking host immune system. Recently, the strategies for immune evasion by the parasite have been unraveled, including immunomodulation to suppress IFN-γ production, elimination of immune cells and soluble immune mediators, and metabolic alterations against reactive oxygen and nitrogen species to fend off the attack from immune system. In this review, we summarized the latest knowledge on immune reaction and immune evasion during amebiasis. PMID:27242782

  3. Immune Response of Amebiasis and Immune Evasion by Entamoeba histolytica.

    PubMed

    Nakada-Tsukui, Kumiko; Nozaki, Tomoyoshi

    2016-01-01

    Entamoeba histolytica is a protozoan parasite and the causative agent of amebiasis. It is estimated approximately 1% of humans are infected with E. histolytica, resulting in an estimate of 100,000 deaths annually. Clinical manifestations of amebic infection range widely from asymptomatic to severe symptoms, including dysentery and extra-intestinal abscesses. Like other infectious diseases, it is assumed that only ~20% of infected individuals develop symptoms, and genetic factors of both the parasite and humans as well as the environmental factors, e.g., microbiota, determine outcome of infection. There are multiple essential steps in amebic infection: degradation of and invasion into the mucosal layer, adherence to the intestinal epithelium, invasion into the tissues, and dissemination to other organs. While the mechanisms of invasion and destruction of the host tissues by the amebae during infection have been elucidated at the molecular levels, it remains largely uncharacterized how the parasite survive in the host by evading and attacking host immune system. Recently, the strategies for immune evasion by the parasite have been unraveled, including immunomodulation to suppress IFN-γ production, elimination of immune cells and soluble immune mediators, and metabolic alterations against reactive oxygen and nitrogen species to fend off the attack from immune system. In this review, we summarized the latest knowledge on immune reaction and immune evasion during amebiasis. PMID:27242782

  4. Powering the Immune System: Mitochondria in Immune Function and Deficiency

    PubMed Central

    Walker, Melissa A.; Sims, Katherine B.; Walter, Jolan E.; Traggiai, Elisabetta

    2014-01-01

    Mitochondria are critical subcellular organelles that are required for several metabolic processes, including oxidative phosphorylation, as well as signaling and tissue-specific processes. Current understanding of the role of mitochondria in both the innate and adaptive immune systems is expanding. Concurrently, immunodeficiencies arising from perturbation of mitochondrial elements are increasingly recognized. Recent observations of immune dysfunction and increased incidence of infection in patients with primary mitochondrial disorders further support an important role for mitochondria in the proper function of the immune system. Here we review current findings. PMID:25309931

  5. Neuropeptides: Keeping The Balance Between Pathogen Immunity and Immune Tolerance

    PubMed Central

    Gonzalez-Rey, Elena; Ganea, Doina; Delgado, Mario

    2010-01-01

    Various neuropeptides have emerged recently as potent immunomodulatory factors with potential for their therapeutic use on immune disorders. Here we highlight the most recent data relevant in the field and we offer our opinion how neuropeptide therapy might impact clinical immune diseases, and the challenges in this field that must be overcome before achieving medical progress. We also review recent reports describing the antimicrobial effects showed by some neuropeptides and the therapeutic, physiological and evolutionary consequences of this new finding. Finally, we discuss how a physiologically functional neuropeptide system contributes to general health and how neuropeptides educate our immune system to be tolerant. PMID:20399708

  6. Powering the immune system: mitochondria in immune function and deficiency.

    PubMed

    Walker, Melissa A; Volpi, Stefano; Sims, Katherine B; Walter, Jolan E; Traggiai, Elisabetta

    2014-01-01

    Mitochondria are critical subcellular organelles that are required for several metabolic processes, including oxidative phosphorylation, as well as signaling and tissue-specific processes. Current understanding of the role of mitochondria in both the innate and adaptive immune systems is expanding. Concurrently, immunodeficiencies arising from perturbation of mitochondrial elements are increasingly recognized. Recent observations of immune dysfunction and increased incidence of infection in patients with primary mitochondrial disorders further support an important role for mitochondria in the proper function of the immune system. Here we review current findings.

  7. Drug-induced immune hemolytic anemia

    MedlinePlus

    Immune hemolytic anemia secondary to drugs; Anemia - immune hemolytic - secondary to drugs ... In some cases, a drug can cause the immune system to mistake your own red blood cells for foreign substances. The body responds by making ...

  8. Immunization Schedules for Preteens and Teens

    MedlinePlus

    ... ACIP Vaccination Recommendations Why Immunize? Vaccines: The Basics Immunization Schedules for Preteens and Teens Recommend on Facebook ... on track. View or Print a Schedule Recommended Immunizations for Preteens and Teens (7-18 years) 2016 ...

  9. Immunization Schedules for Infants and Children

    MedlinePlus

    ... ACIP Vaccination Recommendations Why Immunize? Vaccines: The Basics Immunization Schedules for Infants and Children Recommend on Facebook ... any questions. View or Print a Schedule Recommended Immunizations for Children (Birth through 6 years) Schedule for ...

  10. Brassinosteroids antagonize gibberellin- and salicylate-mediated root immunity in rice.

    PubMed

    De Vleesschauwer, David; Van Buyten, Evelien; Satoh, Kouji; Balidion, Johny; Mauleon, Ramil; Choi, Il-Ryong; Vera-Cruz, Casiana; Kikuchi, Shoshi; Höfte, Monica

    2012-04-01

    Brassinosteroids (BRs) are a unique class of plant steroid hormones that orchestrate myriad growth and developmental processes. Although BRs have long been known to protect plants from a suite of biotic and abiotic stresses, our understanding of the underlying molecular mechanisms is still rudimentary. Aiming to further decipher the molecular logic of BR-modulated immunity, we have examined the dynamics and impact of BRs during infection of rice (Oryza sativa) with the root oomycete Pythium graminicola. Challenging the prevailing view that BRs positively regulate plant innate immunity, we show that P. graminicola exploits BRs as virulence factors and hijacks the rice BR machinery to inflict disease. Moreover, we demonstrate that this immune-suppressive effect of BRs is due, at least in part, to negative cross talk with salicylic acid (SA) and gibberellic acid (GA) pathways. BR-mediated suppression of SA defenses occurred downstream of SA biosynthesis, but upstream of the master defense regulators NONEXPRESSOR OF PATHOGENESIS-RELATED GENES1 and OsWRKY45. In contrast, BR alleviated GA-directed immune responses by interfering at multiple levels with GA metabolism, resulting in indirect stabilization of the DELLA protein and central GA repressor SLENDER RICE1 (SLR1). Collectively, these data favor a model whereby P. graminicola coopts the plant BR pathway as a decoy to antagonize effectual SA- and GA-mediated defenses. Our results highlight the importance of BRs in modulating plant immunity and uncover pathogen-mediated manipulation of plant steroid homeostasis as a core virulence strategy.

  11. Systems Biology and immune aging.

    PubMed

    O'Connor, José-Enrique; Herrera, Guadalupe; Martínez-Romero, Alicia; de Oyanguren, Francisco Sala; Díaz, Laura; Gomes, Angela; Balaguer, Susana; Callaghan, Robert C

    2014-11-01

    Many alterations of innate and adaptive immunity are common in the aging population, which reflect a deterioration of the immune system, and have lead to the terms "immune aging" or "immunosenescence". Systems Biology aims to the comprehensive knowledge of the structure, dynamics, control and design that define a given biological system. Systems Biology benefits from the continuous advances in the omics sciences, based on high-throughput and high-content technologies, as well as on bioinformatic tools for data mining and integration. The Systems Biology approach is becoming gradually used to propose and to test comprehensive models of aging, both at the level of the immune system and the whole organism. In this way, immune aging may be described by a dynamic view of the states and interactions of every individual cell and molecule of the immune system and their role in the context of aging and longevity. This mini-review presents a panoramics of the current strategies, tools and challenges for applying Systems Biology to immune aging.

  12. Dynamics of immune system vulnerabilities

    NASA Astrophysics Data System (ADS)

    Stromberg, Sean P.

    The adaptive immune system can be viewed as a complex system, which adapts, over time, to reflect the history of infections experienced by the organism. Understanding its operation requires viewing it in terms of tradeoffs under constraints and evolutionary history. It typically displays "robust, yet fragile" behavior, meaning common tasks are robust to small changes but novel threats or changes in environment can have dire consequences. In this dissertation we use mechanistic models to study several biological processes: the immune response, the homeostasis of cells in the lymphatic system, and the process that normally prevents autoreactive cells from entering the lymphatic system. Using these models we then study the effects of these processes interacting. We show that the mechanisms that regulate the numbers of cells in the immune system, in conjunction with the immune response, can act to suppress autoreactive cells from proliferating, thus showing quantitatively how pathogenic infections can suppress autoimmune disease. We also show that over long periods of time this same effect can thin the repertoire of cells that defend against novel threats, leading to an age correlated vulnerability. This vulnerability is shown to be a consequence of system dynamics, not due to degradation of immune system components with age. Finally, modeling a specific tolerance mechanism that normally prevents autoimmune disease, in conjunction with models of the immune response and homeostasis we look at the consequences of the immune system mistakenly incorporating pathogenic molecules into its tolerizing mechanisms. The signature of this dynamic matches closely that of the dengue virus system.

  13. Immune therapy for hepatitis B

    PubMed Central

    Al-Mahtab, Mamun; Khan, Md. Sakilur Islam; Raihan, Ruksana; Shrestha, Ananta

    2016-01-01

    Although several antiviral drugs are now available for treatment of patients with chronic hepatitis B (CHB), sustained off-treatment clinical responses and containment of CHB-related complications are not achieved in majority of CHB patients by antiviral therapy. In addition, use of these drugs is endowed with substantial long term risk of viral resistance and drug toxicity. The infinite treatment regimens of antiviral drugs for CHB patients are also costly and usually unbearable by most patients of developing and resource-constrained countries. Taken together, there is a pressing need to develop new and innovative therapeutic approaches for CHB patients. Immune therapy seems to be an alternate therapeutic approach for CHB patients because impaired or distorted or diminished immune responses have been detected in most of these patients. Also, investigators have shown that restoration or induction of proper types of immune responses may have therapeutic implications in CHB. Various immunomodulatory agents have been used to treat patients with CHB around the world and the outcomes of these clinical trials show that the properties of immune modulators and nature and designing of immune therapeutic regimens seem to be highly relevant in the context of treatment of CHB patients. In this review, the general properties and specific features of immune therapy for CHB have been discussed for developing the guidelines of effective regimens of immune therapy for CHB. PMID:27761439

  14. Physical activity, immunity and infection.

    PubMed

    Romeo, J; Wärnberg, J; Pozo, T; Marcos, A

    2010-08-01

    During the last few decades, scientific evidence has confirmed a wide range of health benefits related to regular physical activity. How physical activity affects the immune function and infection risk is, however, still under debate. Commonly, intensive exercise suppresses the activity and levels of several immune cells, while other immune functions may be stimulated by moderate physical activity. With this knowledge, the understanding of the relationship between different levels of physical activity on the immune function has been raised as a potential tool to protect health not only in athletes but also in the general population; the mechanisms that translate a physically active lifestyle into good health continue to be investigated. Reviewing the literature, although several outcomes (i.e. the mechanisms by which different levels and duration of physical activity programmes affect numerous cell types and responses) remain unclear, given that the additional benefits encompass healthy habits including exercise, the use of physical activity programmes may result in improved health of elderly populations. Moderate physical activity or moderate-regulated training may enhance the immune function mainly in less fit subjects or sedentary population and the pre-event fitness status also seems to be an important individual factor regarding this relationship. Although adequate nutrition and regular physical activity habits may synergistically improve health, clinical trials in athletes using nutritional supplements to counteract the immune suppression have been inconclusive so far.Further research is necessary to find out to what extent physical activity training can exert an effect on the immune function.

  15. Dominant resistance against plant viruses

    PubMed Central

    de Ronde, Dryas; Butterbach, Patrick; Kormelink, Richard

    2014-01-01

    To establish a successful infection plant viruses have to overcome a defense system composed of several layers. This review will overview the various strategies plants employ to combat viral infections with main emphasis on the current status of single dominant resistance (R) genes identified against plant viruses and the corresponding avirulence (Avr) genes identified so far. The most common models to explain the mode of action of dominant R genes will be presented. Finally, in brief the hypersensitive response (HR) and extreme resistance (ER), and the functional and structural similarity of R genes to sensors of innate immunity in mammalian cell systems will be described. PMID:25018765

  16. Immunity to Acanthamoeba.

    PubMed

    Ferrante, A

    1991-01-01

    Human serum contains antibodies, mainly of the IgM and IgG isotypes, to pathogenic species of Acanthamoeba. This, as well as the capacity of these amebas to activate complement via the alternative pathway, may be a first-line defense against acanthamoeba infections in humans. Both antibody and complement appear to be important in promoting recognition of these amebas by phagocytic cells such as neutrophils. However, killing of amebas by neutrophils is dependent on lymphokine/monokine priming of the neutrophil. This priming augments the respiratory-burst activity and release of lysosomal enzymes of neutrophils in their response to the ameba. The products of the oxygen-dependent respiratory burst appear to be of prime importance in the killing of this free-living ameba. Antibodies also may prevent tissue invasion by Acanthamoeba by inhibiting its adherence, phagocytic activity, and migration and by neutralizing cytopathogenic amebic agents. Studies on experimental Acanthamoeba infections in mice showed marked species and strain specificity with regard to induction of protection with amebic antigens. Immune compromise or, alternatively, invasion at unique body sites in healthy individuals may form the basis for human infection with Acanthamoeba. PMID:2047675

  17. The immune system and hypertension.

    PubMed

    Singh, Madhu V; Chapleau, Mark W; Harwani, Sailesh C; Abboud, Francois M

    2014-08-01

    A powerful interaction between the autonomic and the immune systems plays a prominent role in the initiation and maintenance of hypertension and significantly contributes to cardiovascular pathology, end-organ damage and mortality. Studies have shown consistent association between hypertension, proinflammatory cytokines and the cells of the innate and adaptive immune systems. The sympathetic nervous system, a major determinant of hypertension, innervates the bone marrow, spleen and peripheral lymphatic system and is proinflammatory, whereas the parasympathetic nerve activity dampens the inflammatory response through α7-nicotinic acetylcholine receptors. The neuro-immune synapse is bidirectional as cytokines may enhance the sympathetic activity through their central nervous system action that in turn increases the mobilization, migration and infiltration of immune cells in the end organs. Kidneys may be infiltrated by immune cells and mesangial cells that may originate in the bone marrow and release inflammatory cytokines that cause renal damage. Hypertension is also accompanied by infiltration of the adventitia and perivascular adipose tissue by inflammatory immune cells including macrophages. Increased cytokine production induces myogenic and structural changes in the resistance vessels, causing elevated blood pressure. Cardiac hypertrophy in hypertension may result from the mechanical afterload and the inflammatory response to resident or migratory immune cells. Toll-like receptors on innate immune cells function as sterile injury detectors and initiate the inflammatory pathway. Finally, abnormalities of innate immune cells and the molecular determinants of their activation that include toll-like receptor, adrenergic, cholinergic and AT1 receptors can define the severity of inflammation in hypertension. These receptors are putative therapeutic targets.

  18. Immune responses to improving welfare.

    PubMed

    Berghman, L R

    2016-09-01

    The relationship between animal welfare and the immune status of an animal has a complex nature. Indeed, the intuitive notion that "increased vigilance of the immune system is by definition better" because it is expected to better keep the animal healthy, does not hold up under scrutiny. This is mostly due to the fact that the immune system consists of 2 distinct branches, the innate and the adaptive immune system. While they are intimately intertwined and synergistic in the living organism, they are profoundly different in their costs, both in terms of performance and wellbeing. In contrast to the adaptive immune system, the action of the innate immune system has a high metabolic cost as well as undesirable behavioral consequences. When a pathogen breaches the first line of defense (often a mucosal barrier), that organism's molecular signature is recognized by resident macrophages. The macrophages respond by releasing a cocktail of pro-inflammatory cytokines (including interleukin-1 and -6) that signal the brain via multiple pathways (humoral as well as neural) of the ongoing peripheral innate immune response. The behavioral response to the release of proinflammatory cytokines, known as "sickness behavior," includes nearly all the behavioral aspects that are symptomatic for clinical depression in humans. Hence, undesired innate immune activity, such as chronic inflammation, needs to be avoided by the industry. From an immunological standpoint, one of the most pressing poultry industry needs is the refinement of our current veterinary vaccine arsenal. The response to a vaccine, especially to a live attenuated vaccine, is often a combination of innate and adaptive immune activities, and the desired immunogenicity comes at the price of high reactogenicity. The morbidity, albeit limited and transient, caused by live vaccines against respiratory diseases and coccidiosis are good examples. Thankfully, the advent of various post-genomics technologies, such as DNA

  19. Precision Immunization: NASA Studies Immune Response to Flu Vaccine

    NASA Video Gallery

    NASA Human Research Program Twins Study investigator Emmanuel Mignot, M.D., Ph.D, known for discovering the cause of narcolepsy is related to the immune system, is studying twin astronauts Scott an...

  20. The multilevel and dynamic interplay between plant and pathogen

    PubMed Central

    Yang, Yifei; Zhou, Jian-Min

    2009-01-01

    Phytopathogens invade into plant apoplast and proliferate by assimilating nutrition from plant cells. Plants depend on sophisticated defensive strategies to resist this invasion. Therefore, pathogenic disease and plant disease resistance are two opposite phases. Fascinating molecular mechanisms uncovered that interactions between plant and pathogen are multilevel and dynamic processes. On one side, plant immunity system contains multiple layers mainly including the perception of common pathogen- associated molecular patterns (PAMPs) using distinct cell-surface pattern-recognition receptors (PRRs) to activate intracellular signaling pathways for broad-spectrum immunity, and the recognition of pathogen virulence proteins by the specific intracellular disease resistance (R) proteins for cultivar-specific immunity. On the opposite side, the bacterial pathogens employ virulence factors, such as phytotoxin and type III effectors (T3SEs) to interfere with the host immunity in different levels. Meanwhile, natural selection drives plants and pathogens to evolve new strategies to confront with each other constantly. The present review highlights recent insights about Arabidopsis immunity and mechanisms for Pseudomonas syringae to counteract this immunity to give a full understanding of plant-pathogen interactions. PMID:19794843