Artigos de revistas: "Pathogen attack"

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MARQUIS, ROBERT J., IVONE R. DINIZ e HELENA C. MORAIS. "Patterns and correlates of interspecific variation in foliar insect herbivory and pathogen attack in Brazilian cerrado". Journal of Tropical Ecology 17, n.º 1 (janeiro de 2001): 127–48. http://dx.doi.org/10.1017/s0266467401001080.

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Patterns of insect herbivore and leaf pathogen attack are described for 25 plant species (10 trees, 10 shrubs and five herbs) at a Brazilian savanna (cerrado) site. Plant and leaf traits were correlated with interspecific variation in attack by herbivores and pathogens in order to account for differences among plant species. Across all species, pathogen damage was 1.5 times higher than insect damage (17.3% vs. 6.8%, respectively). Most insect damage occurred to young leaves while they were expanding (end of the dry season). In contrast, pathogen attack was low on young expanding leaves at the end of the dry season, increased as those leaves matured in the wet season, but continued to increase through the next dry season. Protein-binding capacity was negatively associated with interspecific differences in insect damage to mature leaves. Protein availability and plant height were positive predictors of pathogen attack among plant species, while leaf expansion rate was a significant negative predictor. Interspecific differences in leaf phenology had little effect on the amount of damage caused by either insects or pathogens. However, new leaves produced during the wet season suffered less insect damage than leaves produced during the dry season, the time of greatest leaf production. Timing of young leaf production affected pathogen attack but the season of escape depended on plant species. In contrast, there was no evidence for escape in space as common species were less likely to suffer high pathogen attack than rare species. New and mature leaf toughness, and time for a leaf to reach full expansion all increased from herbs to shrub to trees, while mature leaf nitrogen decreased in that order.

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OPREA, Daniela, Maria JOITA-PACUREANU, Florin Gabriel ANTON e Luxita RISNOVEANU. "The Resistance of Sunflower to the Attack of Some Pathogenic Agents in the Climate Conditions of the Northeast Baragan". Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. Agriculture 79, n.º 2 (20 de novembro de 2022): 54–58. http://dx.doi.org/10.15835/buasvmcn-agr:2022.0034.

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Due to its national economic importance, the sunflower crop has established itself as the main oleaginous crop cultivated in Romania. It faces several diseases that are difficult to fight chemically. The creation of hybrids resistant to the attack of pathogens has proven to be an effective, safe, and environmentally friendly solution. This paper aims to examine the resistance of some biological sunflower creations created in Romania, to the attack of Phomopsis helianthi and Phoma macdonaldi fungi, in 2021. The experiment was placed in field conditions with a natural infestation, at A.R.D.S. Braila. The used biological material was represented by nine new sunflower hybrids. Two problem pathogens were studied: Phomopsis helianthi (perfect stage Diaporthe helianthi) and Phoma macdonaldi (perfect stage Leptosphaeria lindquistii). The climatic conditions of 2021 were favorable for the growth of the pathogens. Phoma macdonaldi had an average attack frequency of 38.8% and an average attack intensity of 1.71%, while Phomopsis helianthi recorded average values of 67.8% and 3.08%, respectively. The lowest attack degree of the Phoma macdonaldi pathogen was found in H3 (0.35%). Regarding the pathogen Phomopsis helianthi, the hybrid H3 showed good resistance, with an attack degree of 1.64%.

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Inal, Jameel M., Ephraim A. Ansa-Addo e Sigrun Lange. "Interplay of host–pathogen microvesicles and their role in infectious disease". Biochemical Society Transactions 41, n.º 1 (29 de janeiro de 2013): 258–62. http://dx.doi.org/10.1042/bst20120257.

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The release of extracellular vesicles, whether MVs (microvesicles) or exosomes, from host cells or intracellular pathogens is likely to play a significant role in the infection process. Host MVs may fuse with pathogen surfaces to deliver host complement regulatory proteins. They may also deliver cytokines that enhance invasion. Decoy functions are also possible. Whereas host MVs may direct pathogens away from their target cells, pathogen MVs may in turn redirect complement membrane-attack complexes away from their target pathogen. An understanding of the mechanisms of this interplay, bringing about both immune evasion and enhanced invasion, will help to direct future research with a view to rendering pathogens more susceptible to immune attack or in improving drug efficacy. It should also be possible to use MVs or exosomes isolated directly from the pathogens, or from the cells infected with pathogens, to provide alternative vaccination strategies.

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Ruano, Guillermo, e David Scheuring. "Plant Cells under Attack: Unconventional Endomembrane Trafficking during Plant Defense". Plants 9, n.º 3 (21 de março de 2020): 389. http://dx.doi.org/10.3390/plants9030389.

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Since plants lack specialized immune cells, each cell has to defend itself independently against a plethora of different pathogens. Therefore, successful plant defense strongly relies on precise and efficient regulation of intracellular processes in every single cell. Smooth trafficking within the plant endomembrane is a prerequisite for a diverse set of immune responses. Pathogen recognition, signaling into the nucleus, cell wall enforcement, secretion of antimicrobial proteins and compounds, as well as generation of reactive oxygen species, all heavily depend on vesicle transport. In contrast, pathogens have developed a variety of different means to manipulate vesicle trafficking to prevent detection or to inhibit specific plant responses. Intriguingly, the plant endomembrane system exhibits remarkable plasticity upon pathogen attack. Unconventional trafficking pathways such as the formation of endoplasmic reticulum (ER) bodies or fusion of the vacuole with the plasma membrane are initiated and enforced as the counteraction. Here, we review the recent findings on unconventional and defense-induced trafficking pathways as the plant´s measures in response to pathogen attack. In addition, we describe the endomembrane system manipulations by different pathogens, with a focus on tethering and fusion events during vesicle trafficking.

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Ávila Méndez, Kelly, e Hernán Mauricio Romero. "Plant responses to pathogen attack: molecular basis of qualitative resistance". Revista Facultad Nacional de Agronomía 70, n.º 2 (1 de maio de 2017): 8225–35. http://dx.doi.org/10.15446/rfna.v70n2.64526.

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Pathogens attack plants to assimilate nutrients from them. All plant species have succeeded in overcoming pathogenic attack; therefore disease condition is not the rule but the exception. A co-evolutionary battle has equipped plants with sophisticated defense mechanisms and cognate pathogens with a corresponding arsenal of counter strategies to overcome them. Traditionally, plant-pathogen interaction has been associated with molecules involved in recognition processes giving rise to models such as the "Zig-zag Model". However, this model is being re-evaluated because it is not consistent with the complexity of the interaction. Current models propose a holistic view of a process where the response is not always determined by the interaction of two molecules. This review discusses the main aspects related to qualitative responses in the plant-pathogen interaction and the new proposed models.

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Zhang, Xue, Yang-Shuo Dai, Yu-Xin Wang, Ze-Zhuo Su, Lu-Jun Yu, Zhen-Fei Zhang, Shi Xiao e Qin-Fang Chen. "Overexpression of the Arabidopsis MACPF Protein AtMACP2 Promotes Pathogen Resistance by Activating SA Signaling". International Journal of Molecular Sciences 23, n.º 15 (7 de agosto de 2022): 8784. http://dx.doi.org/10.3390/ijms23158784.

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Immune response in plants is tightly regulated by the coordination of the cell surface and intracellular receptors. In animals, the membrane attack complex/perforin-like (MACPF) protein superfamily creates oligomeric pore structures on the cell surface during pathogen infection. However, the function and molecular mechanism of MACPF proteins in plant pathogen responses remain largely unclear. In this study, we identified an Arabidopsis MACP2 and investigated the responsiveness of this protein during both bacterial and fungal pathogens. We suggest that MACP2 induces programmed cell death, bacterial pathogen resistance, and necrotrophic fungal pathogen sensitivity by activating the biosynthesis of tryptophan-derived indole glucosinolates and the salicylic acid signaling pathway dependent on the activity of enhanced disease susceptibility 1 (EDS1). Moreover, the response of MACP2 mRNA isoforms upon pathogen attack is differentially regulated by a posttranscriptional mechanism: alternative splicing. In comparison to previously reported MACPFs in Arabidopsis, MACP2 shares a redundant but nonoverlapping role in plant immunity. Thus, our findings provide novel insights and genetic tools for the MACPF family in maintaining SA accumulation in response to pathogens in Arabidopsis.

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Paphitis, Katherine, Camille Achonu, Sandra Callery, Jonathan Gubbay, Kevin Katz, Matthew Muller, Herveen Sachdeva et al. "Beyond flu: Trends in respiratory infection outbreaks in Ontario healthcare settings from 2007 to 2017, and implications for non-influenza outbreak management". Canada Communicable Disease Report 47, n.º 56 (9 de junho de 2021): 269–75. http://dx.doi.org/10.14745/ccdr.v47i56a04.

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Background: Outbreaks cause significant morbidity and mortality in healthcare settings. Current testing methods can identify specific viral respiratory pathogens, yet the approach to outbreak management remains general. Objectives: Our aim was to examine pathogen-specific trends in respiratory outbreaks, including how attack rates, case fatality rates and outbreak duration differ by pathogen between hospitals and long-term care (LTC) and retirement homes (RH) in Ontario. Methods: Confirmed respiratory outbreaks in Ontario hospitals and LTC/RH reported between September 1, 2007, and August 31, 2017, were extracted from the integrated Public Health Information System (iPHIS). Median attack rates and outbreak duration and overall case fatality rates of pathogen-specific outbreaks were compared in both settings. Results: Over the 10-year surveillance period, 9,870 confirmed respiratory outbreaks were reported in Ontario hospitals and LTC/RH. Influenza was responsible for most outbreaks (32% in LTC/RH, 51% in hospitals), but these outbreaks were shorter and had lower attack rates than most non-influenza outbreaks in either setting. Human metapneumovirus, while uncommon (<4% of outbreaks) had high case fatality rates in both settings. Conclusion: Attack rates and case fatality rates varied by pathogen, as did outbreak duration. Development of specific outbreak management guidance that takes into account pathogen and healthcare setting may be useful to limit the burden of respiratory outbreaks.

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Leary, Alexandre Y., Nattapong Sanguankiattichai, Cian Duggan, Yasin Tumtas, Pooja Pandey, Maria E. Segretin, Jose Salguero Linares, Zachary D. Savage, Rui Jin Yow e Tolga O. Bozkurt. "Modulation of plant autophagy during pathogen attack". Journal of Experimental Botany 69, n.º 6 (23 de dezembro de 2017): 1325–33. http://dx.doi.org/10.1093/jxb/erx425.

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HUGHES, G. "Characterizing crop responses to patchy pathogen attack". Plant Pathology 39, n.º 1 (março de 1990): 2–4. http://dx.doi.org/10.1111/j.1365-3059.1990.tb02469.x.

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Lin, Borong, Xue Qing, Jinling Liao e Kan Zhuo. "Role of Protein Glycosylation in Host-Pathogen Interaction". Cells 9, n.º 4 (20 de abril de 2020): 1022. http://dx.doi.org/10.3390/cells9041022.

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Host-pathogen interactions are fundamental to our understanding of infectious diseases. Protein glycosylation is one kind of common post-translational modification, forming glycoproteins and modulating numerous important biological processes. It also occurs in host-pathogen interaction, affecting host resistance or pathogen virulence often because glycans regulate protein conformation, activity, and stability, etc. This review summarizes various roles of different glycoproteins during the interaction, which include: host glycoproteins prevent pathogens as barriers; pathogen glycoproteins promote pathogens to attack host proteins as weapons; pathogens glycosylate proteins of the host to enhance virulence; and hosts sense pathogen glycoproteins to induce resistance. In addition, this review also intends to summarize the roles of lectin (a class of protein entangled with glycoprotein) in host-pathogen interactions, including bacterial adhesins, viral lectins or host lectins. Although these studies show the importance of protein glycosylation in host-pathogen interaction, much remains to be discovered about the interaction mechanism.

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Biniaz, Yaser, Ahmad Tahmasebi, Aminallah Tahmasebi, Benedicte Albrectsen, Péter Poczai e Alireza Afsharifar. "Transcriptome Meta-Analysis Identifies Candidate Hub Genes and Pathways of Pathogen Stress Responses in Arabidopsis thaliana". Biology 11, n.º 8 (1 de agosto de 2022): 1155. http://dx.doi.org/10.3390/biology11081155.

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Following a pathogen attack, plants defend themselves using multiple defense mechanisms to prevent infections. We used a meta-analysis and systems-biology analysis to search for general molecular plant defense responses from transcriptomic data reported from different pathogen attacks in Arabidopsis thaliana. Data from seven studies were subjected to meta-analysis, which revealed a total of 3694 differentially expressed genes (DEGs), where both healthy and infected plants were considered. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis further suggested that the DEGs were involved in several biosynthetic metabolic pathways, including those responsible for the biosynthesis of secondary metabolites and pathways central to photosynthesis and plant–pathogen interactions. Using network analysis, we highlight the importance of WRKY40, WRKY46 and STZ, and suggest that they serve as major points in protein–protein interactions. This is especially true regarding networks of composite-metabolic responses by pathogens. In summary, this research provides a new approach that illuminates how different mechanisms of transcriptome responses can be activated in plants under pathogen infection and indicates that common genes vary in their ability to regulate plant responses to the pathogens studied herein.

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Husaini, Amjad M., Aafreen Sakina e Souliha R. Cambay. "Host–Pathogen Interaction in Fusarium oxysporum Infections: Where Do We Stand?" Molecular Plant-Microbe Interactions® 31, n.º 9 (setembro de 2018): 889–98. http://dx.doi.org/10.1094/mpmi-12-17-0302-cr.

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Fusarium oxysporum, a ubiquitous soilborne pathogen, causes devastating vascular wilt in more than 100 plant species and ranks 5th among the top 10 fungal plant pathogens. It has emerged as a human pathogen, too, causing infections in immune-compromised patients. Therefore, it is important to gain insight into the molecular processes involved in the pathogenesis of this transkingdom pathogen. A complex network comprising interconnected and overlapping signal pathways—mitogen-activated protein kinase signaling pathways, Ras proteins, G-protein signaling components and their downstream pathways, components of the velvet (LaeA/VeA/VelB) complex, and cAMP pathways—is involved in perceiving the host. This network regulates the expression of various pathogenicity genes. However, plants have evolved an elaborate protection system to combat this attack. They, too, possess intricate mechanisms at the molecular level which, once triggered by pathogen attack, transduce signals to activate defense response. This review focuses on understanding and presenting a wholistic picture of the molecular mechanisms of F. oxysporum–host interactions in plant immunity.

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Lee, Junghwan, e Chang-Hwa Song. "Effect of Reactive Oxygen Species on the Endoplasmic Reticulum and Mitochondria during Intracellular Pathogen Infection of Mammalian Cells". Antioxidants 10, n.º 6 (28 de maio de 2021): 872. http://dx.doi.org/10.3390/antiox10060872.

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Oxidative stress, particularly reactive oxygen species (ROS), are important for innate immunity against pathogens. ROS directly attack pathogens, regulate and amplify immune signals, induce autophagy and activate inflammation. In addition, production of ROS by pathogens affects the endoplasmic reticulum (ER) and mitochondria, leading to cell death. However, it is unclear how ROS regulate host defense mechanisms. This review outlines the role of ROS during intracellular pathogen infection, mechanisms of ROS production and regulation of host defense mechanisms by ROS. Finally, the interaction between microbial pathogen-induced ROS and the ER and mitochondria is described.

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Santos, Bráulio A., Mauricio Quesada, Fernando Rosas e Julieta Benítez-Malvido. "Potential Effects of Host Height and Phenology on Adult Susceptibility to Foliar Attack in Tropical Dry Forest Grass". ISRN Ecology 2011 (27 de abril de 2011): 1–7. http://dx.doi.org/10.5402/2011/730801.

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Identifying the sources of variation in plant susceptibility to herbivore and pathogen attack is critical to understand ecological processes determining species abundance and diversity in tropical forests. We assessed the potential effect of tiller height and phenology on standing levels of herbivore and pathogen damage on adults of the woody perennial grass Lasiacis ruscifolia in the tropical dry forest of Chamela, Mexico. Analyses revealed that adult susceptibility to pathogens was greater in small and fruiting tillers than in taller and leaf flushing tillers. Adult susceptibility to herbivores, on the other hand, varied greatly among plants and had no relationship with tiller height and phenology. Our findings suggest that adults highly susceptible to pathogen attack could augment the negative density and distance dependence effects predicted by the Janzen-Connell hypothesis, with potential consequences for the local distribution of the studied species in the forest.

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Hoagland, Robert E. "Chemical Interactions with Bioherbicides to Improve Efficacy". Weed Technology 10, n.º 3 (setembro de 1996): 651–74. http://dx.doi.org/10.1017/s0890037x00040586.

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Bioherbicides can be defined as plant pathogens, phytotoxins derived from pathogens or other microorganisms, augmentatively applied to control weeds. Although many pathogens with bioherbicidal potential have been discovered, most lack sufficient aggressiveness to overcome weed defenses to achieve adequate control. Plants use various physical and biochemical mechanisms to defend against pathogen infectivity, including callose deposition, hydroxyproline-rich glycoprotein accumulation, pathogenesis-related proteins (PR-proteins), phytoalexin production, lignin and phenolic formation, and free radical generation. Some herbicides, plant growth regulators, specific enzyme inhibitors, and other chemicals can alter these defenses. Various pathogens also produce chemical suppressors of plant defenses. Secondary plant metabolism is a major biochemical pathway related to several defense processes. Increased activity of a key enzyme of this pathway, phenylalanine ammonia-lyase (PAL), is often a response to pathogen attack, as demonstrated in two weeds and their associated bioherbicidal pathogens:Alternaria cassiaeon sicklepod andA. crassaon jimsonweed. Weakening of physical and biochemical defenses, and lowering of resistance to pathogen attack, may result from reduced production of phenolics, lignin, and phytoalexins caused by herbicides and other chemicals that affect cuticular component biosynthesis and/or key aspects of secondary plant metabolism. Potent PAL inhibitors [aminooxyacetic acid, α-aminooxy-β-phenylpropionic acid, and (l-amino-2-phenylethyl)phosphonic acid] have some regulatory action on secondary plant metabolism and pathogenicity. Various herbicides and other chemicals dramatically affect extractable PAL activity levels and/or substantially alter PAL product production. Some non-pathogenic organisms can alter herbicide efficacy, and some herbicides influence disease development in plants. Research has shown some synergistic interactions of microbes and chemicals with relevance to weed control. Further research on pathogen interactions with agrochemicals (or other chemicals/regulators) could result in increased efficacy of pathogen-herbicide combinations, reduction of herbicide and pathogen levels required for weed control, and expanded pathogen host range.

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Yao, Nan, Satoshi Imai, Yasuomi Tada, Hitoshi Nakayashiki, Yukio Tosa, Pyoyun Park e Shigeyuki Mayama. "Apoptotic Cell Death is a Common Response to Pathogen Attack in Oats". Molecular Plant-Microbe Interactions® 15, n.º 10 (outubro de 2002): 1000–1007. http://dx.doi.org/10.1094/mpmi.2002.15.10.1000.

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We have examined the characteristics of cell death induced by pathogen infection in oats with respect to following hallmark apoptotic features: DNA laddering, chromatin condensation, and electron microscopic-bterminal deoxynucleotidyl transferase-mediated UTP end labeling positive response. A wide range of plant pathogens representing different levels of parasitism in susceptible and resistant interactions were used for the inocula, which include (i) an obligate parasite, Puccinia coronata f. sp. avenae (the crown rust fungus); (ii) a facultative biotroph parasite, Magnaporthe grisea (the blast fungus); (iii) pathogenic bacteria, Pseudomonas syringae pv. atropurpurea and P. syringae pv. coronafaciens (the halo or stripe blights of oats); and (iv) Ryegrass mottle virus. Surprisingly, any of the pathogens used induced most of the apoptotic features in oat cells at and around the infection sites, indicating that apoptotic cell death is a common phenomenon in oats during pathogen attack. The localization and the timing of apoptotic cell death during a course of infection were, however, quite different depending on the interactions (compatible or incompatible) and the pathogens (fungi, bacteria, or viruses). Possible roles of apoptotic cell death in the susceptible and resistant interactions are discussed.

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PELTONEN, S. "Induced defence responses of cereals to pathogen attack". Agricultural and Food Science 8, n.º 4-5 (4 de janeiro de 1999): 479–92. http://dx.doi.org/10.23986/afsci.5642.

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The defence responses of plants are usually composed of a multitude of structural and biochemical events. Some occur constitutively, whereas others, which are emphasised in this review, are formed in response to pathogen attack and are considered as active reactions of plants. Induction of defence mechanisms can be observed in all plants regardless of their genetic background. Thus, this phenomenon can occur in cultivars with or without known genes for disease resistance. The general defence features of plants may contribute significantly to the overall disease resistance of plants and increasing evidence for the role of different defence molecules are being obtained from molecular studies. In this review, induction of defence mechanisms, especially phenylpropanoid metabolism and its role in the defence responses of cereals to pathogen attack is addressed. Also, induced resistance as a potential tool for disease control in cereals will be briefly discussed.;

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Johnson, Chad, J. Muse Davis, Anna Huttenlocher, John Kernien e Jeniel Nett. "970. Emerging Pathogen Candida auris Evades Neutrophil Attack". Open Forum Infectious Diseases 5, suppl_1 (novembro de 2018): S37. http://dx.doi.org/10.1093/ofid/ofy209.086.

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Abstract Background Candida auris, an emerging fungal pathogen, causes hospital-associated outbreaks of invasive candidiasis with mortality near 60%. Little is known about the pathogenesis of this species that has newly arisen in the last 10 years, and it is unclear why this species is rapidly spreading worldwide. Neutrophils, critical for control of invasive candidiasis, kill fungi through phagocytosis or the release of neutrophil extracellular traps (NETs), which are structures of DNA, histones, and proteins with antimicrobial activity. The objective of this study was to delineate the neutrophil response to C. auris. Methods We examined interactions of human neutrophils with C. auris and included C. albicans for comparison. Neutrophil–Candida interactions were visualized by time-lapse fluorescent microscopy and scanning electron microscopy (SEM). We utilized oxidative stress indicator CM-H2DCFDA to measure the generation of reactive oxygen species (ROS) in neutrophils. NET formation was quantified by Sytox Green staining and assessed by SEM and immunofluorescent labeling of NET-associated proteins. Fungal viability was evaluated using microbiological counts and viability stains. We utilized a zebrafish larvae infection model to evaluate neutrophil–Candida interactions in vivo. Results Imaging revealed the phagocytosis of C. albicans by human neutrophils followed by the formation of NETs. In contrast, neutrophils encountering C. auris rarely engaged in phagocytosis or produced NETs. By Sytox Green staining, C. auris triggered negligible NET release by human neutrophils, with levels 7-fold lower when compared with C. albicans (Figure A). C. auris did not induce neutrophils to generate ROS, a key signaling mechanism for NET formation. The ineffective neutrophil response to C. auris correlated with diminished fungal killing (Figure B). Imaging of neutrophils in a zebrafish model of invasive candidiasis revealed the recruitment of approximately 50% fewer neutrophils in response to C. auris when compared with C. albicans (Figure C). Conclusion C. auris evades neutrophils by altering multiple aspects of their usual anti-candidal responses. We propose that this diminished innate immune response may contribute to the unexpected virulence of C. auris. Disclosures All authors: No reported disclosures.

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Basri, Hasan. "Texture Feature Extraction of Pathogen Microscopic Image Using Discrete Wavelet Transform". Jurnal Riset Informatika 5, n.º 1 (14 de dezembro de 2022): 549–54. http://dx.doi.org/10.34288/jri.v5i1.488.

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This study used a case study of Jabon leaves, and the pathogen is one of the causes of disease that attack the leaves of jabon, one of the leaf spots and leaf blight. Discovery of leaf spot disease in different pathogens and leaf blight. The pathogen was obtained from the leaf spot of Curvularia sp. 1 and Pestalotia sp., while the pathogen came from Curvularia sp. 2 and Botrytis sp. Identify the pathogen as soon as possible to minimize its effects. Improper handling can lead to increased virulence and resistance to the pathogen. Improper handling also can cause a disease outbreak (disease epidemic) in a region. This study is the first step in identifying the pathogens responsible for Jabon leaf disease. In this study, the Application of Koch's Postulates method to achieve the purification of pathogens and retrieve the microscopic pathogen image as the data acquisition stage. Furthermore, use of the segmentation stage to separate the object pathogen from the background, and one of the methods used is Otsu Thresholding. The extraction process of pathogen microscopic image using Discrete Wavelet Transform (DWT), DWT extraction results can be obtained using energy and entropy information.

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Irawan, S., e E. Antriyandarti. "BIOTRICO: A Breakthrough Fertilizer for Sustainable Agriculture". IOP Conference Series: Earth and Environmental Science 940, n.º 1 (1 de dezembro de 2021): 012047. http://dx.doi.org/10.1088/1755-1315/940/1/012047.

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Abstract The second goal of Sustainable Development Goals is to end hunger, achieve food security and improved nutrition as well as promote sustainable agriculture. Within the framework of sustainable development, agriculture has dimensions as a complex ecosystem of which biodiversity and productivity must be maintained. Accordingly, organic agriculture is an agricultural system that holistically pays attention to the sustainability of biodiversity, biological cycles, and soil biological activities. The problems faced by farmers are the attack of disease-causing pathogens; the level of pathogen attack can even cause crop failure. Phytophthora infestans is a pathogen that causes root, stem, and leaf disease, and this disease is hazardous for plants. Phytophthora infestans are challenging to control, easily transmitted, and have the highest virulence when the plant is in the vegetative period. Therefore, this research aims to determine the level of effectiveness of BIOTRICO in controlling Phytophthora infestans by using experimental method in CV Agrolestari Merbabu. From the experimental results, BIOTRICO was able to minimize the attack of pathogens to only 20%, much lower than the control (60%) and proven capability to become a better option in root, stem, and leaf disease than chemical pesticides for sustainable agricultural practice.

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Dehgahi, Raheleh, Sreeramanan Subramaniam, Latiffah Zakaria, Alireza Joniyas, Farid Beiki Firouzjahi, Kianoosh Haghnama e Mohammad Razinataj. "Review of Research on Fungal Pathogen Attack and Plant Defense Mechanism against Pathogen". International Journal of Scientific Research in Agricultural Sciences 2, n.º 8 (1 de agosto de 2015): 197–208. http://dx.doi.org/10.12983/ijsras-2015-p0197-0208.

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Danu Tuheteru, Faisal, Sri Utami, Illa Anggraeni, Husna Husna e Agus Kurniawan. "PENYAKIT BERCAK DAUN PADA BIBIT BITTI (Vitex cofassusReinw.) DI PERSEMAIAN". Jurnal Pemuliaan Tanaman Hutan 15, n.º 2 (30 de dezembro de 2021): 77–84. http://dx.doi.org/10.20886/jpth.2021.15.2.77-84.

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Bitti (Vitex cofassusReinw.) is a native plant species in Sulawesi which belongs to Verbenaceae family. This species has great potential to be developed as a house construction material, boat base material, and household utensils. Development of bitti silviculture techniques is very necessary in supporting the efforts to develop these plants. One of problems in this cultivation is disease attack. This study aimed to determine symptoms of disease attack, level of severity, determine kind of pathogen that cause disease, and analyzesome factors that cause pathogen attack on bitti seedlings. The results showed that leaf spot disease was found on bitti seedlings with level of severity 33.22%. The identification results showed that the pathogen causing leaf spot diseaseis the fungus, namely Curvularia sp. Microclimate conditions such as temperature and humidity assumedtoaffect the emergence of pathogen on bitti seedlings. The attack of Curvularia sp tends to affect the growth of bitti seedlings.

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Butt, Ghazala Rauf, Zainab Abdul Qayyum e Matthew Alan Jones. "Plant Defence Mechanisms Are Modulated by the Circadian System". Biology 9, n.º 12 (9 de dezembro de 2020): 454. http://dx.doi.org/10.3390/biology9120454.

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Plant health is an important aspect of food security, with pathogens, pests, and herbivores all contributing to yield losses in crops. Plants’ defence against pathogens is complex and utilises several metabolic processes, including the circadian system, to coordinate their response. In this review, we examine how plants’ circadian rhythms contribute to defence mechanisms, particularly in response to bacterial pathogen attack. Circadian rhythms contribute to many aspects of the plant–pathogen interaction, although significant gaps in our understanding remain to be explored. We conclude that if these relationships are explored further, better disease management strategies could be revealed.

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Baruah, Indrani, Gajendra Mohan Baldodiya, Jagajjit Sahu e Geetanjali Baruah. "Dissecting the Role of Promoters of Pathogen-sensitive Genes in Plant Defense". Current Genomics 21, n.º 7 (22 de outubro de 2020): 491–503. http://dx.doi.org/10.2174/1389202921999200727213500.

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Plants inherently show resistance to pathogen attack but are susceptible to multiple bacteria, viruses, fungi, and phytoplasmas. Diseases as a result of such infection leads to the deterioration of crop yield. Several pathogen-sensitive gene activities, promoters of such genes, associated transcription factors, and promoter elements responsible for crosstalk between the defense signaling pathways are involved in plant resistance towards a pathogen. Still, only a handful of genes and their promoters related to plant resistance have been identified to date. Such pathogen-sensitive promoters are accountable for elevating the transcriptional activity of certain genes in response to infection. Also, a suitable promoter is a key to devising successful crop improvement strategies as it ensures the optimum expression of the required transgene. The study of the promoters also helps in mining more details about the transcription factors controlling their activities and helps to unveil the involvement of new genes in the pathogen response. Therefore, the only way out to formulate new solutions is by analyzing the molecular aspects of these promoters in detail. In this review, we provided an overview of the promoter motifs and cis-regulatory elements having specific roles in pathogen attack response. To elaborate on the importance and get a vivid picture of the pathogen-sensitive promoter sequences, the key motifs and promoter elements were analyzed with the help of PlantCare and interpreted with available literature. This review intends to provide useful information for reconstructing the gene networks underlying the resistance of plants against pathogens.

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Zhu, Qian-Hao, Wei-Xing Shan, Michael A. Ayliffe e Ming-Bo Wang. "Epigenetic Mechanisms: An Emerging Player in Plant-Microbe Interactions". Molecular Plant-Microbe Interactions® 29, n.º 3 (março de 2016): 187–96. http://dx.doi.org/10.1094/mpmi-08-15-0194-fi.

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Plants have developed diverse molecular and cellular mechanisms to cope with a lifetime of exposure to a variety of pathogens. Host transcriptional reprogramming is a central part of plant defense upon pathogen recognition. Recent studies link DNA methylation and demethylation as well as chromatin remodeling by posttranslational histone modifications, including acetylation, methylation, and ubiquitination, to changes in the expression levels of defense genes upon pathogen challenge. Remarkably these inducible defense mechanisms can be primed prior to pathogen attack by epigenetic modifications and this heightened resistance state can be transmitted to subsequent generations by inheritance of these modification patterns. Beside the plant host, epigenetic mechanisms have also been implicated in virulence development of pathogens. This review highlights recent findings and insights into epigenetic mechanisms associated with interactions between plants and pathogens, in particular bacterial and fungal pathogens, and demonstrates the positive role they can have in promoting plant defense.

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Ku, Yee-Shan, Sau-Shan Cheng, Aisha Gerhardt, Ming-Yan Cheung, Carolina A. Contador, Lok-Yiu Winnie Poon e Hon-Ming Lam. "Secretory Peptides as Bullets: Effector Peptides from Pathogens against Antimicrobial Peptides from Soybean". International Journal of Molecular Sciences 21, n.º 23 (5 de dezembro de 2020): 9294. http://dx.doi.org/10.3390/ijms21239294.

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Soybean is an important crop as both human food and animal feed. However, the yield of soybean is heavily impacted by biotic stresses including insect attack and pathogen infection. Insect bites usually make the plants vulnerable to pathogen infection, which causes diseases. Fungi, oomycetes, bacteria, viruses, and nematodes are major soybean pathogens. The infection by pathogens and the defenses mounted by soybean are an interactive and dynamic process. Using fungi, oomycetes, and bacteria as examples, we will discuss the recognition of pathogens by soybean at the molecular level. In this review, we will discuss both the secretory peptides for soybean plant infection and those for pathogen inhibition. Pathogenic secretory peptides and peptides secreted by soybean and its associated microbes will be included. We will also explore the possible use of externally applied antimicrobial peptides identical to those secreted by soybean and its associated microbes as biopesticides.

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Trandafirescu, M., A. Indreias e I. Trandafirescu. "EVALUATION OF APRICOT BREEDING SELECTION RESISTANCE TO PATHOGEN ATTACK". Acta Horticulturae, n.º 903 (agosto de 2011): 241–45. http://dx.doi.org/10.17660/actahortic.2011.903.30.

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Islam, Waqar, Ali Noman, Muhammad Qasim e Liande Wang. "Plant Responses to Pathogen Attack: Small RNAs in Focus". International Journal of Molecular Sciences 19, n.º 2 (8 de fevereiro de 2018): 515. http://dx.doi.org/10.3390/ijms19020515.

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McCullough, Kenneth C., Nicolas Ruggli e Artur Summerfield. "Dendritic cells—At the front-line of pathogen attack". Veterinary Immunology and Immunopathology 128, n.º 1-3 (março de 2009): 7–15. http://dx.doi.org/10.1016/j.vetimm.2008.10.290.

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Leontovyčová, Hana, Tetiana Kalachova e Martin Janda. "Disrupted actin: a novel player in pathogen attack sensing?" New Phytologist 227, n.º 6 (13 de maio de 2020): 1605–9. http://dx.doi.org/10.1111/nph.16584.

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MAUCH-MANI, B. "Salicylic Acid and Systemic Acquired Resistance to Pathogen Attack". Annals of Botany 82, n.º 5 (novembro de 1998): 535–40. http://dx.doi.org/10.1006/anbo.1998.0726.

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Kanwar, Poonam, e Gopaljee Jha. "Alterations in plant sugar metabolism: signatory of pathogen attack". Planta 249, n.º 2 (28 de setembro de 2018): 305–18. http://dx.doi.org/10.1007/s00425-018-3018-3.

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Mukherjee, Rukmini, e Ivan Dikic. "Regulation of Host-Pathogen Interactions via the Ubiquitin System". Annual Review of Microbiology 76, n.º 1 (8 de setembro de 2022): 211–33. http://dx.doi.org/10.1146/annurev-micro-041020-025803.

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Ubiquitination is a posttranslational modification that regulates a multitude of cellular functions. Pathogens, such as bacteria and viruses, have evolved sophisticated mechanisms that evade or counteract ubiquitin-dependent host responses, or even exploit the ubiquitin system to their own advantage. This is largely done by numerous pathogen virulence factors that encode E3 ligases and deubiquitinases, which are often used as weapons in pathogen–host cell interactions. Moreover, upon pathogen attack, host cellular signaling networks undergo major ubiquitin-dependent changes to protect the host cell, including coordination of innate immunity, remodeling of cellular organelles, reorganization of the cytoskeleton, and reprogramming of metabolic pathways to restrict growth of the pathogen. Here we provide mechanistic insights into ubiquitin regulation of host-pathogen interactions and how it affects bacterial and viral pathogenesis and the organization and response of the host cell.

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Shahzadi, Iqra, Aqeel Ahmad, Nasim Ahmad Yasin, Ghulam Fareed, Yaseen Ashraf, Waheed Akram, Waheed Ullah Khan e Muhammad Tayyab. "First report of Alternaria brassicicola causing leaf spots on garlic, an important food and medicinal plant". Journal of Medicinal Botany 1 (1 de maio de 2017): 08. http://dx.doi.org/10.25081/jmb.2017.v1.48.

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Timely reporting new pathogens in an area is very important to design crop cultivation strategies. Current study describes the attack of Alternaria brassicicola over garlic, an important food and medicinal plant in Punjab, Pakistan. Pathogen was successfully isolated over artificial fungal growth medium and its microscopic characteristics were studied morphologically. Its identification was confirmed by targeting ribosomal DNA (ribotyping) prior to its submission in Fungal Culture Bank of Pakistan (FCBP). The isolated pathogen was tested for its pathogenicity under greenhouse conditions. Furthermore, the phylogenetic homology of the pathogen was checked with previously reported fungal isolates. The study was preceded according to the design and requirements of Koch’s postulates; and the pathogenicity of the isolated fungal species was confirmed.

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García-Guzmán, Graciela, e Julieta Benítez-Malvido. "Effect of litter on the incidence of leaf-fungal pathogens and herbivory in seedlings of the tropical tree Nectandra ambigens". Journal of Tropical Ecology 19, n.º 2 (6 de fevereiro de 2003): 171–77. http://dx.doi.org/10.1017/s0266467403003195.

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Effects of litter cover on insect herbivory, leaf-fungal damage, and seedling performance (survival, growth in height and leaf number), were assessed on established Nectandra ambigens seedlings in three sites of a Mexican tropical rain forest. Naturally occurring seedlings were measured for height, leaf number and standing levels of leaf damage by herbivores and pathogens. Thereafter, seedlings were exposed for 1 y to three litter treatments: (1) litter addition, (2) control and (3) continuous litter removal. There was a significant effect of site on the proportion of surviving seedlings and on the relative growth rates in terms of leaf number. Overall, seedlings with higher initial leaf number showed higher survival and produced more leaves after 12 mo than seedlings with lower initial leaf number. Litter addition resulted in seedlings with lower relative growth rates in height and higher levels of damage by herbivores and pathogens. On average, leaf area damaged by pathogens was < 6% and herbivory was < 27%. Seedlings with higher levels of herbivory showed higher levels of pathogen attack. Herbivory and pathogen attack had no effect on seedling performance. This study reveals the importance of litter-cover on the interactions between seedlings, herbivores and pathogens, as well as on the performance of tropical seedlings.

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Mendoza-Soto, Ana Belén, Amada Zulé Rodríguez-Corral, Adriana Bojórquez-López, Maylin Cervantes-Rojo, Claudia Castro-Martínez e Melina Lopez-Meyer. "Arbuscular Mycorrhizal Symbiosis Leads to Differential Regulation of Genes and miRNAs Associated with the Cell Wall in Tomato Leaves". Biology 11, n.º 6 (2 de junho de 2022): 854. http://dx.doi.org/10.3390/biology11060854.

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Arbuscular mycorrhizal symbiosis is an association that provides nutritional benefits to plants. Importantly, it induces a physiological state allowing plants to respond to a subsequent pathogen attack in a more rapid and intense manner. Consequently, mycorrhiza-colonized plants become less susceptible to root and shoot pathogens. This study aimed to identify some of the molecular players and potential mechanisms related to the onset of defense priming by mycorrhiza colonization, as well as miRNAs that may act as regulators of priming genes. The upregulation of cellulose synthases, pectinesterase inhibitors, and xyloglucan endotransglucosylase/hydrolase, as well as the downregulation of a pectinesterase, suggest that the modification and reinforcement of the cell wall may prime the leaves of mycorrhizal plants to react faster and stronger to subsequent pathogen attack. This was confirmed by the findings of miR164a-3p, miR164a-5p, miR171e-5p, and miR397, which target genes and are also related to the biosynthesis or modification of cell wall components. Our findings support the hypothesis that the reinforcement or remodeling of the cell wall and cuticle could participate in the priming mechanism triggered by mycorrhiza colonization, by strengthening the first physical barriers upstream of the pathogen encounter.

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Bano, Ambreen, Anmol Gupta, Manas Ranjan Prusty e Manoj Kumar. "Elicitation of Fruit Fungi Infection and Its Protective Response to Improve the Postharvest Quality of Fruits". Stresses 3, n.º 1 (30 de janeiro de 2023): 231–55. http://dx.doi.org/10.3390/stresses3010018.

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Fruit diseases brought on by fungus infestation leads to postharvest losses of fresh fruit. Approximately 30% of harvested fruits do not reach consumers’ plates due to postharvest losses. Fungal pathogens play a substantial part in those losses, as they cause the majority of fruit rots and consumer complaints. Understanding fungal pathogenic processes and control measures is crucial for developing disease prevention and treatment strategies. In this review, we covered the presented pathogen entry, environmental conditions for pathogenesis, fruit’s response to pathogen attack, molecular mechanisms by which fungi infect fruits in the postharvest phase, production of mycotoxin, virulence factors, fungal genes involved in pathogenesis, and recent strategies for protecting fruit from fungal attack. Then, in order to investigate new avenues for ensuring fruit production, existing fungal management strategies were then assessed based on their mechanisms for altering the infection process. The goal of this review is to bridge the knowledge gap between the mechanisms of fungal disease progression and numerous disease control strategies being developed for fruit farming.

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Banks, Jonathan, e Glynn Percival. "Evaluation of Biostimulants to Control Guignardia Leaf Blotch (Guignardia aesculi) of Horsechestnut and Black Spot (Diplocarpon rosae) of Roses". Arboriculture & Urban Forestry 38, n.º 6 (1 de novembro de 2012): 258–61. http://dx.doi.org/10.48044/jauf.2012.035.

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Biostimulants are classified as materials that are neither a fertilizer nor a pesticide, but when applied to a plant will enhance their health, growth, and protection. Manufacturers claim biostimulants have underexploited potential in providing protectant properties to plants against pathogen attack. This study evaluated the efficacy of seven commercially available biostimulants against the foliar pathogens Guignardia aesculi, leaf blotch of horsechestnut (Aesculus hippocastanum L.) and Diplocarpon rosae black spot of roses (Rosa “Pretty Polly”). None of the biostimulant products tested in this investigation achieved a sufficient degree of pathogen control to warrant replacement of or supplementation with conventional synthetic fungicides.

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Inglese, S. J., e N. D. Paul. "Tolerance of Senecio vulgaris to Infection and Disease Caused by Native and Alien Rust Fungi". Phytopathology® 96, n.º 7 (julho de 2006): 718–26. http://dx.doi.org/10.1094/phyto-96-0718.

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Plant defense strategies against pathogen attack can be divided into either resistance or tolerance. Variation in tolerance is expressed as differences in the relationship between host fitness (or yield) and the degree of infection. Plant tolerance of pathogen attack remains poorly understood both in terms of its specific mechanisms and in terms of the evolutionary processes by which it has arisen. Theoretical models predict that it is the result of coevolution between host and pathogen, suggesting greater tolerance in interactions with native as opposed to introduced pathogens. Therefore, we quantified and compared the degree of tolerance expressed in the interaction of Senecio vulgaris with the rust fungus Coleosporium tussilginis, which is native to the UK, and the introduced rust fungus Puccinia lagenophorae. We used the reaction norm approach to quantify tolerance and its components. The S. vulgaris-C. tussilaginis interaction expressed a significantly greater degree of tolerance, as reductions in host growth and fitness per unit infection were significantly less than with P. lagenophorae. The key mechanism for this greater tolerance to C. tussilaginis was a significantly smaller reduction in photosynthesis per unit infection than with P. lagenophorae, at both leaf and whole plant scales. There was no significant difference in the relationship between whole plant photosynthesis and host reproduction. We discuss these responses in the context of coevolution for tolerance in host-pathogen interactions.

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Arnaudov, Veselin, Stefan Gandev e Milena Dimova. "Susceptibility of Some Walnut Cultivars to Gnomonia leptostyla and Xanthomonas arboricola pv. juglandis in Bulgaria". АГРОЗНАЊЕ 15, n.º 1 (15 de junho de 2015): 41. http://dx.doi.org/10.7251/agren1401041a.

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The aim of the present research was to study and compare the susceptibility of 13 walnut cultivars – 5 Bulgarian (B), 3 French (F), 2 Hungarian (H), and 3 American (A) – to Gnomonia leptostyla (Fr.) and Xanthomonas arboricola pv. juglandis (Pierce) Dye, the pathogens causing leaf spot and walnut blight. The study was conducted under natural environmental conditions in a 5-8-year-old walnut collection orchard of the Fruit Growing Institute – Plovdiv, during the period 2006-2010. The evaluation of the attack produced by these pathogens was carried out on different organs leaves and nuts in two periods of the year (June and October). All the studied cultivars were distributed in 6 different levels of susceptibility to a given pathogen based on the degree of attack. The article presents data on the sensitivity of the studied walnut cultivars to the attack to G. leptostyla (Fr.) and X. arboricola pv. juglandis (Pierce) Dye and discusses the results obtained.

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Gómez-Ariza, Jorge, Sonia Campo, Mar Rufat, Montserrat Estopà, Joaquima Messeguer, Blanca San Segundo e María Coca. "Sucrose-Mediated Priming of Plant Defense Responses and Broad-Spectrum Disease Resistance by Overexpression of the Maize Pathogenesis-Related PRms Protein in Rice Plants". Molecular Plant-Microbe Interactions® 20, n.º 7 (julho de 2007): 832–42. http://dx.doi.org/10.1094/mpmi-20-7-0832.

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Expression of pathogenesis-related (PR) genes is part of the plant's natural defense response against pathogen attack. The PRms gene encodes a fungal-inducible PR protein from maize. Here, we demonstrate that expression of PRms in transgenic rice confers broad-spectrum protection against pathogens, including fungal (Magnaporthe oryzae, Fusarium verticillioides, and Helminthosporium oryzae) and bacterial (Erwinia chrysanthemi) pathogens. The PRms-mediated disease resistance in rice plants is associated with an enhanced capacity to express and activate the natural plant defense mechanisms. Thus, PRms rice plants display a basal level of expression of endogenous defense genes in the absence of the pathogen. PRms plants also exhibit stronger and quicker defense responses during pathogen infection. We also have found that sucrose accumulates at higher levels in leaves of PRms plants. Sucrose responsiveness of rice defense genes correlates with the pathogen-responsive priming of their expression in PRms rice plants. Moreover, pretreatment of rice plants with sucrose enhances resistance to M. oryzae infection. Together, these results support a sucrose-mediated priming of defense responses in PRms rice plants which results in broad-spectrum disease resistance.

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MALINAS, Cristian, Ioan OROIAN, Antonia ODAGIU, Cristrian IEDERAN e Alexandra SUCIU. "Meta - Models Efficiency in Assessing the Vegetal Pathogens Attack". Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. Agriculture 70, n.º 2 (25 de novembro de 2013): 347–51. http://dx.doi.org/10.15835/buasvmcn-agr:9754.

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The use of meta-models approach as component of the prevention strategy against different pathogens attack, specific for vegetal cultures, receives an increasing interest. Due to the importance ofÂ theÂ climaticÂ influenceÂ uponÂ pathogensÂ action,Â almostÂ allÂ theseÂ approachesÂ useÂ theÂ inputsÂ from meteorological stations placed in field. Another important component of such a system is represented byÂ aÂ specificÂ softwareÂ programÂ usedÂ forÂ estimationÂ ofÂ virtualÂ geographicalÂ distributionÂ ofÂ target pathogen/pathogens.Â ThisÂ articleÂ aimsÂ toÂ emphasizeÂ the possibilityÂ ofÂ usingÂ theÂ meta-modelsÂ for predicting Phytophtora infestans Mont.Â deÂ BaryÂ attack. The research wasÂ carriedÂ onÂ duringÂ spring - autumn 2012 in a potato field located in Jucu village, on the experimental field of the UASMV Cluj - Napoca.Â ClimaticÂ conditionsÂ (temperatureÂ andÂ rainfallÂ regimen)Â andÂ attackÂ degreeÂ wereÂ monitored usingÂ aÂ meteorologicalÂ stationÂ placedÂ onÂ theÂ field,Â andÂ observations.Â RainfallÂ regimenÂ andÂ average dailyÂ temperatureÂ were takenÂ intoÂ consideration,Â inÂ approachingÂ theÂ multiregressionÂ modelÂ withÂ tow inputs. TheÂ statisticalÂ dataÂ processingÂ wasÂ performedÂ withÂ STATISTICAÂ 7.0Â v.Â programme.Â The analysisÂ ofÂ varianceÂ (ANOVA)Â appliedÂ toÂ theÂ interactionÂ betweenÂ attackÂ degreeÂ of Phytophthora infestansÂ Mont.Â deÂ BaryÂ inÂ potato -Â temperature -Â rainfallÂ allowsÂ usÂ toÂ useÂ theÂ proposed multiregressionÂ modelÂ (FÂ =Â 7,892,Â pÂ <Â 0.001).Â TheÂ multiregressionÂ analyzeÂ emphasizeÂ aÂ strong multiple correlation coefficient of 0.895 which accounts from 81.10% of the predicted attack degree. TheÂ regressionÂ line,Â YÂ =Â Â Â 24.311Â +Â 2.813X1Â +Â 0.122X2Â show,Â inÂ climaticÂ conditionsÂ specificÂ forÂ the experimentalÂ yearÂ 2012,Â Â Â theÂ biggerÂ influenceÂ (moreÂ thanÂ twice)Â ofÂ theÂ thermicÂ conditionsÂ onÂ the Phytophthora infestans Mont. de Bary attack degree in potato, compared to rainfall influence on the same pathogen.Obtaining the regression parameters allows us to build a meta-model for predicting the evolution of the Phytophthora infestans Mont. de Bary attack degree in potato, reliable in a high share, 81.10%, respectively, and presenting the advantage that it gives comparable results, which contribute to increase the consistency of assessments patterns.

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Meyer, Susan E., Julie Beckstead e Phil S. Allen. "Niche specialization in Bromus tectorum seed bank pathogens". Seed Science Research 28, n.º 3 (13 de junho de 2018): 215–21. http://dx.doi.org/10.1017/s0960258518000193.

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AbstractNiche theory predicts that when two species exhibit major niche overlap, one will eventually be eliminated through competitive exclusion. Thus, some degree of niche specialization is required to facilitate coexistence. We examined whether two important seed bank pathogens on the invasive winter annual grass Bromus tectorum (cheatgrass, downy brome) exhibit niche specialization. These pathogens utilize seed resources in complementary ways. Pyrenophora semeniperda is specialized to attack dormant seeds. It penetrates directly through the seed coverings. Hyphae ramify first through the endosperm and then throughout the seed. Seed death results as the embryo is consumed. In contrast, the Fusarium seed rot pathogen (Fusarium sp.) is specialized to attack non-dormant seeds in the early stages of germination. It cannot penetrate seed coverings directly. Instead, it responds to a cue emanating from the radicle end with directional hyphal growth and subsequent penetration at the point of radicle emergence, causing seed death. Non-dormant seeds usually escape P. semeniperda through germination even if infected because it develops more slowly than Fusarium. When water stress slows non-dormant seed germination, both P. semeniperda and Fusarium can attack and cause seed mortality more effectively. The Fusarium seed rot pathogen can sometimes reach epidemic levels and may result in B. tectorum stand failure (‘die-off’). Stands usually re-establish from the persistent seed bank, but if P. semeniperda has also reached high levels and eliminated the seed bank, a die-off can persist indefinitely.

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Hardham, Adrienne R., e David M. Cahill. "The role of oomycete effectors in plant - pathogen interactions". Functional Plant Biology 37, n.º 10 (2010): 919. http://dx.doi.org/10.1071/fp10073.

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Plants constantly come into contact with a diverse range of microorganisms that are potential pathogens, and they have evolved multi-faceted physical and chemical strategies to inhibit pathogen ingress and establishment of disease. Microbes, however, have developed their own strategies to counteract plant defence responses. Recent research on plant–microbe interactions has revealed that an important part of the infection strategies of a diverse range of plant pathogens, including bacteria, fungi and oomycetes, is the production of effector proteins that are secreted by the pathogen and that promote successful infection by manipulating plant structure and metabolism, including interference in plant defence mechanisms. Pathogen effector proteins may function either in the extracellular spaces within plant tissues or within the plant cell cytoplasm. Extracellular effectors include cell wall degrading enzymes and inhibitors of plant enzymes that attack invading pathogens. Intracellular effectors move into the plant cell cytoplasm by as yet unknown mechanisms where, in incompatible interactions, they may be recognised by plant resistance proteins but where, in compatible interactions, they may suppress the plant’s immune response. This article presents a brief overview of our current understanding of the nature and function of effectors produced by oomycete plant pathogens.

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Miller, Gabriel A., Judith K. Pell e Stephen J. Simpson. "Crowded locusts produce hatchlings vulnerable to fungal attack". Biology Letters 5, n.º 6 (12 de agosto de 2009): 845–48. http://dx.doi.org/10.1098/rsbl.2009.0495.

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Transgenerational effects of parental experience on offspring immunity are well documented in the vertebrate literature (where antibodies play an obligatory role), but have only recently been described in invertebrates. We have assessed the impact of parental rearing density upon offspring disease resistance by challenging day-old locust hatchlings ( Schistocerca gregaria ) from either crowd- or solitary-reared parents with the fungal pathogen Metarhizium anisopliae var. acridum . When immersed in standardized conidia suspensions, hatchlings from gregarious parents suffered greater pathogen-induced mortality than hatchlings from solitary-reared parents. This observation contradicts the basic theory of positive density-dependent prophylaxis and demonstrates that crowding has a transgenerational influence upon locust disease resistance.

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Kupfer, Tom R., e Daniel M. T. Fessler. "Ectoparasite defence in humans: relationships to pathogen avoidance and clinical implications". Philosophical Transactions of the Royal Society B: Biological Sciences 373, n.º 1751 (4 de junho de 2018): 20170207. http://dx.doi.org/10.1098/rstb.2017.0207.

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Currently, disgust is regarded as the main adaptation for defence against pathogens and parasites in humans. Disgust's motivational and behavioural features, including withdrawal, nausea, appetite suppression and the urge to vomit, defend effectively against ingesting or touching sources of pathogens. However, ectoparasites do not attack their hosts via ingestion, but rather actively attach themselves to the body surface. Accordingly, by itself, disgust offers limited defence against ectoparasites. We propose that, like non-human animals, humans have a distinct ectoparasite defence system that includes cutaneous sensory mechanisms, itch-generation mechanisms and grooming behaviours. The existence of adaptations for ectoparasite defence is supported by abundant evidence from non-human animals, as well as more recent evidence concerning human responses to ectoparasite cues. Several clinical disorders may be dysfunctions of the ectoparasite defence system, including some that are pathologies of grooming, such as skin picking and trichotillomania, and others, such as delusory parasitosis and trypophobia, which are pathologies of ectoparasite detection. We conclude that future research should explore both distinctions between, and overlap across, ectoparasite defence systems and pathogen avoidance systems, as doing so will not only illuminate proximate motivational systems, including disgust, but may also reveal important clinical and social consequences. This article is part of the Theo Murphy meeting issue ‘Evolution of pathogen and parasite avoidance behaviours'.

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Farahani, Ali Safaie, e Mohsen Taghavi. "Changes of antioxidant enzymes of mung bean [Vigna radiata (L.) R. Wilczek] in response to host and non-host bacterial pathogens". Journal of Plant Protection Research 56, n.º 1 (1 de janeiro de 2016): 95–99. http://dx.doi.org/10.1515/jppr-2016-0016.

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Abstract The natural resistance against the majority of potential pathogens that exist in most plant species is known as non-host resistance. Several reports suggest the role of antioxidant enzymes in non-host resistance. We assayed the expression or activity of four scavenging enzymes during non-host pathogen-plant interaction (Xanthomonas hortorum pv. pelargonii/mung bean) and host pathogen-plant interaction (Xanthomonas axonopodis pv. phaseoli/mung bean). The expression of superoxide dismutase (SOD) and ascorbate peroxidase (APX) and the enzyme activity of catalase (CAT) and peroxidase (POX) were investigated. The activities of CAT and POX were higher during non-host pathogen invasion vs. host pathogen attack. The expression of SOD and APX were also different between compatible and incompatible interactions. The expression of SOD and APX were higher in the incompatible compared to the compatible interaction. Additionally, induction of the antioxidant enzymes in response to non-host pathogen was earlier than induction in response to host pathogen. Such information is important for plant breeders, and useful when looking for alternative control strategies as well.

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Lippok, Bernadette, Rainer P. Birkenbihl, Gaelle Rivory, Janna Brümmer, Elmon Schmelzer, Elke Logemann e Imre E. Somssich. "Expression of AtWRKY33 Encoding a Pathogen- or PAMP-Responsive WRKY Transcription Factor Is Regulated by a Composite DNA Motif Containing W Box Elements". Molecular Plant-Microbe Interactions® 20, n.º 4 (abril de 2007): 420–29. http://dx.doi.org/10.1094/mpmi-20-4-0420.

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WRKY transcription factors regulate distinct parts of the plant defense transcriptome. Expression of many WRKY genes themselves is induced by pathogens or pathogen-mimicking molecules. Here, we demonstrate that Arabidopsis WRKY33 responds to various stimuli associated with plant defense as well as to different kinds of phytopathogens. Although rapid pathogen-induced AtWRKY33 expression does not require salicylic acid (SA) signaling, it is dependent on PAD4, a key regulator upstream of SA. Activation of AtWRKY33 is independent of de novo protein synthesis, suggesting that it is at least partly under negative regulatory control. We show that a set of three WRKY-specific cis-acting DNA elements (W boxes) within the AtWRKY33 promoter is required for efficient pathogen- or PAMP-triggered gene activation. This strongly indicates that WRKY transcription factors are major components of the regulatory machinery modulating immediate to early expression of this gene in response to pathogen attack.

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Parvaiz, Aqsa, Ghulam Mustafa e Faiz A. Joyia. "UNDERSTANDING INVASIVE PLANT MYCOPARASITES AND THEIR REMEDY THROUGH ADVANCED MOLECULAR APPROACHES". Pakistan Journal of Phytopathology 30, n.º 2 (27 de dezembro de 2018): 213. http://dx.doi.org/10.33866/phytopathol.030.02.0452.

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Fungi are historically notorious pests that have threatened availability of quality food. Several invasive species have appeared to be destructive for valuable crop species and even led to famine in certain severe cases. Surveillance and eradication of these disastrous microbial invaders is dependent on their sentinel behavior. Molecular Biology has helped to great extent in understanding these epidemic agents. Plant defense system as well as plant microbe interaction have well been explored and proved quite fruitful in understanding metabolic pathways involved in pathogenesis and defense response. Ultimately, researchers are able to define strategies for the control of these invasive pathogens. Genome editing has successfully been employed to develop pathogen resistant crops. Antifungal proteins have been expressed through transgenic technology to develop disease resistant plants. A few have proved to be the real success stories whereas others are at the stage of infancy. This review is an update about research work accomplished to-date, for the characterization and identification of fungal pathogens, metabolic pathways activated during plant pathogen interaction, advancements in the detection of fungal pathogens and transgenic plants developed to withstand pathogen attack.

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Goodman, B. A. "The involvement of oxygen-derived free radicals in plant–pathogen interactions". Proceedings of the Royal Society of Edinburgh. Section B. Biological Sciences 102 (1994): 479–93. http://dx.doi.org/10.1017/s0269727000014500.

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SynopsisPlants have evolved a multiplicity of defence mechanisms against pathogen attack. Their modes of action may be to (i) kill the pathogen directly, (ii) block the action of enzymes required for infection, or (iii) erect barriers to pathogen growth. Some of these reactions proceed via free radical intermediates and make use of either atmospheric oxygen or reactive oxygen species. This paper reviews the various types of reaction involving oxygen-derived free radicals that are initiated in plant tissue when it is invaded by pathogenic organisms. Both the production of free radicals by plants in defensive processes and the utilisation of free radicals by pathogens in offensive reactions are considered and particular attention is given to the use of electron paramagnetic resonance (EPR) spectroscopy for the direct observation of such free radical reactions.

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