Jonah Piovia-Scott; Karen L. Pope; Sharon P. Lawler; Esther M. Cole; Janet E. Foley
The fungal pathogen Batrachochytrium dendrobatidis (Bd), which causes the disease chytridiomycosis, has been associated with declines and extinctions of montane amphibians worldwide. To gain insight into factors affecting its distribution and prevalence we focus on the amphibian community of the Klamath Mountains in northwest...
Heitman, Joseph; Carter, Dee A.; Dyer, Paul S.; Soll, David R.
We review here recent advances in our understanding of sexual reproduction in fungal pathogens that commonly infect humans, including Candida albicans, Cryptococcus neoformans/gattii, and Aspergillus fumigatus. Where appropriate or relevant, we introduce findings on other species associated with human infections. In particular, we focus on rapid advances involving genetic, genomic, and population genetic approaches that have reshaped our view of how fungal pathogens evolve. Rather than being asexual, mitotic, and largely clonal, as was thought to be prevalent as recently as a decade ago, we now appreciate that the vast majority of pathogenic fungi have retained extant sexual, or parasexual, cycles. In some examples, sexual and parasexual unions of pathogenic fungi involve closely related individuals, generating diversity in the population but with more restricted recombination than expected from fertile, sexual, outcrossing and recombining populations. In other cases, species and isolates participate in global outcrossing populations with the capacity for considerable levels of gene flow. These findings illustrate general principles of eukaryotic pathogen emergence with relevance for other fungi, parasitic eukaryotic pathogens, and both unicellular and multicellular eukaryotic organisms. PMID:25085958
Allan, E.; Ruijven, van J.; Crawley, M.J.
By attacking plants, herbivorous mammals, insects, and belowground pathogens are known to play an important role in maintaining biodiversity in grasslands. Foliar fungal pathogens are ubiquitous in grassland ecosystems, but little is known about their role as drivers of community composition and
Bolton, M.D.; Thomma, B.P.H.J.
Over the course of evolution, fungi have adapted to occupy specific niches, from symbiotically inhabiting the flora of the intestinal tract of mammals to saprophytic growth on leaf litter resting on the forest floor. In Plant Fungal Pathogens: Methods and Protocols, expert researchers in the field
Loginov, Dmitry; Šebela, Marek
Fungal pathogens are causal agents of numerous human, animal, and plant diseases. They employ various infection modes to overcome host defense systems. Infection mechanisms of different fungi have been subjected to many comprehensive studies. These investigations have been facilitated by the development of various '-omics' techniques, and proteomics has one of the leading roles in this regard. Fungal conidia and sclerotia could be considered the most important structures for pathogenesis as their germination is one of the first steps towards a host infection. They represent interesting objects for proteomic studies because of the presence of unique proteins with unexplored biotechnological potential required for pathogen viability, development and the subsequent host infection. Proteomic peculiarities of survival structures of different fungi, including those of biotechnological significance (e.g., Asperillus fumigatus, A. nidulans, Metarhizium anisopliae), in a dormant state, as well as changes in the protein production during early stages of fungal development are the subjects of the present review. We focused on biological aspects of proteomic studies of fungal survival structures rather than on an evaluation of proteomic approaches. For that reason, proteins that have been identified in this context are discussed from the point of view of their involvement in different biological processes and possible functions assigned to them. This is the first review paper summarizing recent advances in proteomics of fungal survival structures. Copyright © 2016 Elsevier B.V. All rights reserved.
Möller, Mareike; Stukenbrock, Eva H
The fungal kingdom comprises some of the most devastating plant pathogens. Sequencing the genomes of fungal pathogens has shown a remarkable variability in genome size and architecture. Population genomic data enable us to understand the mechanisms and the history of changes in genome size and adaptive evolution in plant pathogens. Although transposable elements predominantly have negative effects on their host, fungal pathogens provide prominent examples of advantageous associations between rapidly evolving transposable elements and virulence genes that cause variation in virulence phenotypes. By providing homogeneous environments at large regional scales, managed ecosystems, such as modern agriculture, can be conducive for the rapid evolution and dispersal of pathogens. In this Review, we summarize key examples from fungal plant pathogen genomics and discuss evolutionary processes in pathogenic fungi in the context of molecular evolution, population genomics and agriculture.
Knogge, W.; Gierlich, A.; Max-Planck-Institute for Plant Breeding,; Van't Slot, K.A.E.; Papavoine, T.
Full text: Induction of plant defence reactions and, hence, genotype-specific disease resistance results from the interaction of highly specific plant resistance (R) genes with matching pathogen avirulence (Avr) genes (gene-for-gene interactions). More than thirty R genes acting against different types of pathogens (viruses, bacteria, fungi, oomycetes, nematodes) have been isolated from various plants species. However, with few exceptions it remains to be shown how their products recognise the complementary Avr gene products. To date, Avr genes and their products have been characterised from only three fungal species. These include the NIP1 gene from Rhynchosporium secalis, the causal agent of barley leaf scald. It encodes a small, secreted protein, NIP1, that triggers defence reactions exclusively in barley cultivars expressing the R gene Rrs1. NIP1 also non-specifically stimulates the H + -ATPase activity in barley plasma membranes, suggesting that the host recognition system targets a putative fungal virulence factor. Virulent fungal strains lack the gene or carry an allele encoding a non-functional product. Four NIP1 iso-forms have been characterised; NIP1-I and NIP1-II although both elicitor-active display different levels of activity, whereas the isoforms NIP1-III and NIP1-IV are inactive. After establishing a heterologous expression system, the single amino acids specifying NIP1-III and NIP1-IV were integrated into the NIP1-I sequence and yielded the inactive mutant proteins NIP1-III* and NIP1-IV*. The elicitor-inactive isoforms were also unable to stimulate the H + -ATPase, suggesting that both functions of NIP1 are mediated by a single plant receptor. The 3D structure of NIP1-I has been elucidated by 1 H- and 15 N-NMR spectroscopy. Binding studies using 125 I-NIP1-I revealed a single class of high-affinity binding sites on membranes from both Rrs1- and rrs1-cultivars, suggesting that NIP1-binding is not sufficient for defence triggering and that an
Dean, R.; Kan, van J.A.L.; Pretorius, Z.A.; Hammond-Kosack, K.E.; Pietro, Di A.; Spanu, P.D.; Rudd, J.J.; Dickman, M.; Kahmann, R.; Ellis, J.; Foster, G.D.
The aim of this review was to survey all fungal pathologists with an association with the journal Molecular Plant Pathology and ask them to nominate which fungal pathogens they would place in a ‘Top 10’ based on scientific/economic importance. The survey generated 495 votes from the international
Powell, Jennifer R; Ausubel, Frederick M
The nematode Caenorhabditis elegans is a simple model host for studying the relationship between the animal innate immune system and a variety of bacterial and fungal pathogens. Extensive genetic and molecular tools are available in C. elegans, facilitating an in-depth analysis of host defense factors and pathogen virulence factors. Many of these factors are conserved in insects and mammals, indicating the relevance of the nematode model to the vertebrate innate immune response. Here, we describe pathogen assays for a selection of the most commonly studied bacterial and fungal pathogens using the C. elegans model system.
... fungal pathogens associated with water hyacinth. Several potential pathogen isolates including Alternaria eichhorniae, Cercospora sp. and Acremonium zonatum were identified. Isolates of Cercospora sp. and A. eichhorniae were evaluated for their effectiveness on water hyacinth plants in the screen bouse. The disease ...
Stotz, H.U.; Mitrousia, G.K.; Wit, de P.J.G.M.; Fitt, B.D.L.
R gene-mediated host resistance against apoplastic fungal pathogens is not adequately explained by the terms pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) or effector-triggered immunity (ETI). Therefore, it is proposed that this type of resistance is termed
He, Dan; Hao, Jilong; Gao, Song; Wan, Xue; Wang, Wanting; Shan, Qiushi; Wang, Li
Fungal keratitis is a worldwide-distributed refractory and potentially blinding ocular infection caused by various fungi. It is necessary to investigate the etiological and epidemiological characteristics of this disease and establish a rapid and specific pathogenic identification method. Here, we isolated and identified fungal pathogens of 275 patients with presumed fungal keratitis from Jilin Province, China, and conducted statistical analyses of epidemiological information. The positive rate of fungal culture was 72.0 %. Fusarium sp. was the most common genus among 210 fungal isolates. The predominant species were Fusarium solani, Aspergillus fumigatus, and Candida glabrata, which accounted for over 50 % of the isolated organisms. Corneal trauma and previous use of drugs were the most important predisposing factors. In addition, a multiplex polymerase chain reaction (PCR) was designed with species-specific primers of the three species that could identify them with amplicons of approximately 330 bp from F. solani, 275 bp from A. fumigatus, and 230 bp from C. glabrata. Additionally, PCR with fungal universal primers and multiplex PCR were performed using DNA prepared by an improved DNA extraction method from corneal scrapings. With this method, fungal pathogens from corneal scrapings could be specifically and rapidly identified within 8 h. The culture-independent rapid identification of corneal scrapings may have great significance for the early diagnosis and treatment of fungal keratitis.
Full Text Available AIM:To investigate the clinical characteristics and distribution of pathogens in patients with fungal keratitis and to provide evidence for diagnosis and treatment of this disease.METHODS:The clinical data of 98 cases(98 eyeswith fungal keratitis from January 2012 to July 2015 in the First Affiliated Hospital of Yangtze University were retrospectively reviewed.RESULTS:The main cause for fungal keratitis was corneal injury by plants. The inappropriate use of contact lenses and glucocorticoids therapy were the next cause. Almost all of the patients had hyphae moss, pseudopodia, immune ring, and satellite signs. A few of patients had endothelial plaque and anterior chamber empyema. The majority pathogens of fungal keratitis was Fusarium spp(73.5%,followed by Aspergillus spp(13.2%,Candida spp(9.2%and others(4.1%.Sixty-five patients(65 eyestreated with 5% natamycin were cured. The condition of 15 patients was improved. Eighteen patients were invalid, in which 13 patients became better and 5 patients became worse after voriconazole was added into the therapy, leading to amniotic membrance cover in 3 patients and eyeball removal in 2 patients at last.CONCLUSION:Fusarium genus is the predominant pathogen for fungal keratitis in Jingzhou. Natamycin can be used as the preferred drug for the prevention and treatment for fungal keratitis. The clinicians should pay attention to the fungal keratitis, in order to early diagnosis and timely treatment.
Full Text Available Objective: To isolate and identify of marine fungal metabolites against clinical bacterial pathogens. To optimize the production medium for isolated fungus. Method: Marine fungus isolated from water and sediment samples from different places of Sundarbans mangrove, Muttukadu (Chennai and Parangipettai in India. Antimicrobial substance from marine fungi was produced by agar plate method. The potent fungal were inoculated on production medium and extracted was done. The extracted compound was checked for anti bacterial activity. Suitable production medium were optimized. Result: Totally 30 fungal isolates were recovered and morphologically 10 different strains were belongs to the fungal genera such as Fusarium, Aspergillus, Mucor and Penicillium. Preliminary screening results showed 3 fungal isolates showed promising activity. After production of potent fungal SS2 crude extracts showed highest inhibition against the bacterial pathogens out of 3 fungal isolates. The results showed maximum zone in 20mm against E.coli and minimum 10 mm against Vibrio sp. Conclusions: The present study identified Fusarium sp isolated from Sundarbans mangrove water as a potential source for bioactive compounds. Further isolation of active compound from potential fungal isolates will leads to the discovery of effective antimicrobials.
Cassell, Gail H; Gutierrez-Fuentes, Jose A; Barquero, Fernando; Nombela, Cesar
... and Evolutionary Dynamics of Pathogens * 21 Keith A. Crandall and Marcos Pérez-Losada II. Evolutionary Genetics of Microbial Pathogens 4. Environmental and Social Influences on Infectious Disea...
Perez-Nadales, Elena; Nogueira, Maria Filomena Almeida; Baldin, Clara; Castanheira, Sónia; El Ghalid, Mennat; Grund, Elisabeth; Lengeler, Klaus; Marchegiani, Elisabetta; Mehrotra, Pankaj Vinod; Moretti, Marino; Naik, Vikram; Oses-Ruiz, Miriam; Oskarsson, Therese; Schäfer, Katja; Wasserstrom, Lisa; Brakhage, Axel A; Gow, Neil A R; Kahmann, Regine; Lebrun, Marc-Henri; Perez-Martin, José; Di Pietro, Antonio; Talbot, Nicholas J; Toquin, Valerie; Walther, Andrea; Wendland, Jürgen
Fungi have the capacity to cause devastating diseases of both plants and animals, causing significant harvest losses that threaten food security and human mycoses with high mortality rates. As a consequence, there is a critical need to promote development of new antifungal drugs, which requires a comprehensive molecular knowledge of fungal pathogenesis. In this review, we critically evaluate current knowledge of seven fungal organisms used as major research models for fungal pathogenesis. These include pathogens of both animals and plants; Ashbya gossypii, Aspergillus fumigatus, Candida albicans, Fusarium oxysporum, Magnaporthe oryzae, Ustilago maydis and Zymoseptoria tritici. We present key insights into the virulence mechanisms deployed by each species and a comparative overview of key insights obtained from genomic analysis. We then consider current trends and future challenges associated with the study of fungal pathogenicity. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.
Perez-Nadales, Elena; Almeida Nogueira, Maria Filomena; Baldin, Clara; Castanheira, Sónia; El Ghalid, Mennat; Grund, Elisabeth; Lengeler, Klaus; Marchegiani, Elisabetta; Mehrotra, Pankaj Vinod; Moretti, Marino; Naik, Vikram; Oses-Ruiz, Miriam; Oskarsson, Therese; Schäfer, Katja; Wasserstrom, Lisa; Brakhage, Axel A.; Gow, Neil A.R.; Kahmann, Regine; Lebrun, Marc-Henri; Perez-Martin, José; Di Pietro, Antonio; Talbot, Nicholas J.; Toquin, Valerie; Walther, Andrea; Wendland, Jürgen
Fungi have the capacity to cause devastating diseases of both plants and animals, causing significant harvest losses that threaten food security and human mycoses with high mortality rates. As a consequence, there is a critical need to promote development of new antifungal drugs, which requires a comprehensive molecular knowledge of fungal pathogenesis. In this review, we critically evaluate current knowledge of seven fungal organisms used as major research models for fungal pathogenesis. These include pathogens of both animals and plants; Ashbya gossypii, Aspergillus fumigatus, Candida albicans, Fusarium oxysporum, Magnaporthe oryzae, Ustilago maydis and Zymoseptoria tritici. We present key insights into the virulence mechanisms deployed by each species and a comparative overview of key insights obtained from genomic analysis. We then consider current trends and future challenges associated with the study of fungal pathogenicity. PMID:25011008
We are entering a new era in plant pathology where whole-genome sequences of many individuals of a pathogen species are becoming readily available. This era of pathogen population genomics will provide new opportunities and challenges, requiring new computational and analytical tools. Population gen...
Ouellette, G. B.; Baayen, R. P.; Chamberland, H.; Simard, M.; Rioux, D.; Charest, P. M.
Antibodies to detect pectin in present investigations attached to distinct fibrils in vessel lumina. In carnation infected with an isolate of Fusarium oxysporum f.sp., labeling of pathogen cells also occurred; in a resistant cultivar (cv.), it was coincident with proximate pectin fibrils and linked to altered fungal walls, which was the opposite in the susceptible cv., indicating that hindrance of pathogen ability to degrade pectin may be related to resistance. Labeling of the fungus in culture was nil, except in media containing pectin, showing that pectin is not native to the pathogen. Labeling of fungal walls for cellulose in elm (inoculated with Ophiostoma novo-ulmi) and carnation also occurred, linked to adsorbed host wall components. The chitin probe often attached to dispersed matter, in vessel lumina, traceable to irregularly labeled fungal cells and host wall degradation products. With an anti-horseradish peroxidase probe, host and fungal walls were equally labeled, and with a glucosidase, differences of labeling between these walls were observed, depending on pH of the test solution. Fungal extracellular matter and filamentous structures, present in fungal walls, predominantly in another elm isolate (Phaeotheca dimorphospora), did not label with any of the probes used. However, in cultures of this fungus, extracellular material labeled, even at a distance from the colony margin, with an anti-fimbriae probe.
Susan E. Meyer; Julie Beckstead; JanaLynn Pearce
Bromus tectorum L. (cheatgrass or downy brome) presents a rich resource for soil microorganisms because of its abundant production of biomass, seeds, and surface litter. Many of these organisms are opportunistic saprophytes, but several fungal species regularly found in B. tectorum stands function as facultative or obligate pathogens. These organisms interact...
Xue, Chaoyang; Tada, Yasuomi; Dong, Xinnian; Heitman, Joseph
Cryptococcus is a globally distributed human fungal pathogen that primarily afflicts immunocompromised individuals. How and why this human fungal pathogen associates with plants and how this environmental niche influences its life cycle remains a mystery. We established Cryptococcus-Arabidopsis and Cryptococcus-Eucalyptus systems and discovered that Cryptococcus proliferates and mates on plant surfaces. Mating efficiency of C. gattii was markedly enhanced on plants and myo-inositol and indole acetic acid were specific plant products that stimulated mating. On Arabidopsis, dwarfing and chlorosis were observed following infection with a fungal mixture of two opposite mating-type strains, but not with either mating-type alone. This infection process is countered by the plant jasmonate-mediated defense mechanism. These findings reveal that Cryptococcus can parasitically interact with plants to complete its sexual cycle, which may impact an understanding of the origin and evolution of both plant and animal fungal pathogens in nature.
Full Text Available Syrah decline has been increasingly seen and reported in many vineyards worldwide. In recent years, an increase in samples of Vitis vinifera cv. Syrah showing general decline has also been noted in Spain. Sixty-two samples of Syrah grafted grapevines with such symptoms were collected from grapevine nurseries and young vineyards between 2007 and 2009 and subjected to fungal isolation. Species were identified with morphological and molecular methods. Species recovered included Phaeoacremonium, Botryosphaeriaceae and Cylindrocarpon, as well as Pa. chlamydospora and Ca. luteo-olivacea. The study demonstrates that fungal pathogens should be considered potential factors associated with Syrah decline.
Full Text Available Host cells use an intricate signaling system to respond to invasions by pathogenic microorganisms. Although several signaling components of disease resistance against necrotrophic fungal pathogens have been identified, our understanding for how molecular components and host processes contribute to plant disease susceptibility is rather sparse. Here, we identified four transcription factors (TFs from Arabidopsis that limit pathogen spread. Arabidopsis mutants defective in any of these TFs displayed increased disease susceptibility to Botrytis cinerea and Plectosphaerella cucumerina, and a general activation of non-immune host processes that contribute to plant disease susceptibility. Transcriptome analyses revealed that the mutants share a common transcriptional signature of 77 up-regulated genes. We characterized several of the up-regulated genes that encode peptides with a secretion signal, which we named PROVIR (for provirulence factors. Forward and reverse genetic analyses revealed that many of the PROVIRs are important for disease susceptibility of the host to fungal necrotrophs. The TFs and PROVIRs identified in our work thus represent novel genetic determinants for plant disease susceptibility to necrotrophic fungal pathogens.
Ikeh, Mélanie; Ahmed, Yasmin; Quinn, Janet
The ability of pathogenic fungi to acquire essential macro and micronutrients during infection is a well-established virulence trait. Recent studies in the major human fungal pathogens Candida albicans and Cryptococcus neoformans have revealed that acquisition of the essential macronutrient, phosphate, is essential for virulence. The phosphate sensing and acquisition pathway in fungi, known as the PHO pathway, has been extensively characterized in the model yeast Saccharomyces cerevisiae . In this review, we highlight recent advances in phosphate sensing and signaling mechanisms, and use the S. cerevisiae PHO pathway as a platform from which to compare the phosphate acquisition and storage strategies employed by several human pathogenic fungi. We also explore the multi-layered roles of phosphate acquisition in promoting fungal stress resistance to pH, cationic, and oxidative stresses, and describe emerging roles for the phosphate storage molecule polyphosphate (polyP). Finally, we summarize the recent studies supporting the necessity of phosphate acquisition in mediating the virulence of human fungal pathogens, highlighting the concept that this requirement is intimately linked to promoting resistance to host-imposed stresses.
Full Text Available Postharvest diseases cause losses in a wide variety of crops around the world. Irradiation, a useful nonchemical approach, has been used as an alternative treatment for fungicide to control plant fungal pathogens. For a preliminary study, ionizing radiations (gamma, X-ray, or e-beam irradiation were evaluated for their antifungal activity against Botrytis cinerea, Penicillium expansum, and Rhizopus stolonifer through mycelial growth, spore germination, and morphological analysis under various conditions. Different fungi exhibited different radiosensitivity. The inhibition of fungal growth showed in a dose-dependent manner. Three fungal pathogens have greater sensitivity to the e-beam treatment compared to gamma or X-ray irradiations. The inactivation of individual fungal-viability to different irradiations can be considered between 3–4 kGy for B. cinerea and 1–2 kGy for P. expansum and R. stolonifer based on the radiosensitive and radio-resistant species, respectively. These preliminary data will provide critical information to control postharvest diseases through radiation.
Chernin, L.; Ismailov, Z.; Haran, S.; Chet, I.
Three Enterobacter agglomerans strains which produce and excrete proteins with chitinolytic activity were found while screening soil-borne bacteria antagonistic to fungal plant pathogens. The chitinolytic activity was induced when the strains were grown in the presence of colloidal chitin as the sole carbon source. It was quantitated by using assays with chromogenic p-nitrophenyl analogs of disaccharide, trisaccharide, and tetrasaccharide derivatives of N-acetylglucosamine. A set of three flu...
Gong, Zifan; Karlsson, Amy J
Cell-penetrating peptides (CPPs) are small peptides capable of crossing cellular membranes while carrying molecular cargo. Although they have been widely studied for their ability to translocate nucleic acids, small molecules, and proteins into mammalian cells, studies of their interaction with fungal cells are limited. In this work, we evaluated the translocation of eleven fluorescently labeled peptides into the important human fungal pathogens Candida albicans and C. glabrata and explored the mechanisms of translocation. Seven of these peptides (cecropin B, penetratin, pVEC, MAP, SynB, (KFF) 3 K, and MPG) exhibited substantial translocation (>80% of cells) into both species in a concentration-dependent manner, and an additional peptide (TP-10) exhibiting strong translocation into only C. glabrata. Vacuoles were involved in translocation and intracellular trafficking of the peptides in the fungal cells and, for some peptides, escape from the vacuoles and localization in the cytosol were correlated to toxicity toward the fungal cells. Endocytosis was involved in the translocation of cecropin B, MAP, SynB, MPG, (KFF) 3 K, and TP-10, and cecropin B, penetratin, pVEC, and MAP caused membrane permeabilization during translocation. These results indicate the involvement of multiple translocation mechanisms for some CPPs. Although high levels of translocation were typically associated with toxicity of the peptides toward the fungal cells, SynB was translocated efficiently into Candida cells at concentrations that led to minimal toxicity. Our work highlights the potential of CPPs in delivering antifungal molecules and other bioactive cargo to Candida pathogens. © 2017 The Protein Society.
Gardiner, Donald M; Kazan, Kemal; Manners, John M
The constant interaction between plants and their pathogens has resulted in the evolution of a diverse array of microbial infection strategies. It is increasingly evident that horizontal acquisition of new virulence functions in fungi is one of the evolutionary processes that maintain pathogens' competitive edge over host plants. Genome analyses of fungi are pointing towards this phenomenon being particularly prevalent in the subphylum Pezizomycota. While the extent of cross-kingdom gene transfer can be determined with existing genomic tools and databases, so far very few horizontally transmitted genes have been functionally characterised, and an understanding of their physiological roles in virulence has been determined for even fewer genes. Understanding the evolutionary selection pressures that drive the retention of acquired genes in particular fungal lineages is important, as it will undoubtedly reveal new insights into both fungal virulence mechanisms and corresponding plant defence processes in the future. Crown Copyright © 2013. Published by Elsevier Ireland Ltd. All rights reserved.
Dean, Ralph; Van Kan, Jan A L; Pretorius, Zacharias A; Hammond-Kosack, Kim E; Di Pietro, Antonio; Spanu, Pietro D; Rudd, Jason J; Dickman, Marty; Kahmann, Regine; Ellis, Jeff; Foster, Gary D
The aim of this review was to survey all fungal pathologists with an association with the journal Molecular Plant Pathology and ask them to nominate which fungal pathogens they would place in a 'Top 10' based on scientific/economic importance. The survey generated 495 votes from the international community, and resulted in the generation of a Top 10 fungal plant pathogen list for Molecular Plant Pathology. The Top 10 list includes, in rank order, (1) Magnaporthe oryzae; (2) Botrytis cinerea; (3) Puccinia spp.; (4) Fusarium graminearum; (5) Fusarium oxysporum; (6) Blumeria graminis; (7) Mycosphaerella graminicola; (8) Colletotrichum spp.; (9) Ustilago maydis; (10) Melampsora lini, with honourable mentions for fungi just missing out on the Top 10, including Phakopsora pachyrhizi and Rhizoctonia solani. This article presents a short resumé of each fungus in the Top 10 list and its importance, with the intent of initiating discussion and debate amongst the plant mycology community, as well as laying down a bench-mark. It will be interesting to see in future years how perceptions change and what fungi will comprise any future Top 10. © 2012 THE AUTHORS. MOLECULAR PLANT PATHOLOGY © 2012 BSPP AND BLACKWELL PUBLISHING LTD.
Langenbach, Caspar; Schultheiss, Holger; Rosendahl, Martin; Tresch, Nadine; Conrath, Uwe; Goellner, Katharina
Fungal pathogens pose a major challenge to global crop production. Crop varieties that resist disease present the best defence and offer an alternative to chemical fungicides. Exploiting durable nonhost resistance (NHR) for crop protection often requires identification and transfer of NHR-linked genes to the target crop. Here, we identify genes associated with NHR of Arabidopsis thaliana to Phakopsora pachyrhizi, the causative agent of the devastating fungal disease called Asian soybean rust. We transfer selected Arabidopsis NHR-linked genes to the soybean host and discover enhanced resistance to rust disease in some transgenic soybean lines in the greenhouse. Interspecies NHR gene transfer thus presents a promising strategy for genetically engineered control of crop diseases. © 2015 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.
Christopher A Desjardins
Full Text Available Paracoccidioides is a fungal pathogen and the cause of paracoccidioidomycosis, a health-threatening human systemic mycosis endemic to Latin America. Infection by Paracoccidioides, a dimorphic fungus in the order Onygenales, is coupled with a thermally regulated transition from a soil-dwelling filamentous form to a yeast-like pathogenic form. To better understand the genetic basis of growth and pathogenicity in Paracoccidioides, we sequenced the genomes of two strains of Paracoccidioides brasiliensis (Pb03 and Pb18 and one strain of Paracoccidioides lutzii (Pb01. These genomes range in size from 29.1 Mb to 32.9 Mb and encode 7,610 to 8,130 genes. To enable genetic studies, we mapped 94% of the P. brasiliensis Pb18 assembly onto five chromosomes. We characterized gene family content across Onygenales and related fungi, and within Paracoccidioides we found expansions of the fungal-specific kinase family FunK1. Additionally, the Onygenales have lost many genes involved in carbohydrate metabolism and fewer genes involved in protein metabolism, resulting in a higher ratio of proteases to carbohydrate active enzymes in the Onygenales than their relatives. To determine if gene content correlated with growth on different substrates, we screened the non-pathogenic onygenale Uncinocarpus reesii, which has orthologs for 91% of Paracoccidioides metabolic genes, for growth on 190 carbon sources. U. reesii showed growth on a limited range of carbohydrates, primarily basic plant sugars and cell wall components; this suggests that Onygenales, including dimorphic fungi, can degrade cellulosic plant material in the soil. In addition, U. reesii grew on gelatin and a wide range of dipeptides and amino acids, indicating a preference for proteinaceous growth substrates over carbohydrates, which may enable these fungi to also degrade animal biomass. These capabilities for degrading plant and animal substrates suggest a duality in lifestyle that could enable pathogenic
Debets, A.J.M.; Dalstra, H.J.P.; Slakhorst, S.M.; Koopmanschap-Memelink, A.B.; Hoekstra, R.F.; Saupe, S.J.
Prions are infectious proteins that cause fatal diseases in mammals. Prions have also been found in fungi, but studies on their role in nature are scarce. The proposed biological function of fungal prions is debated and varies from detrimental to benign or even beneficial. [Het-s] is a prion of the
Soler-Hurtado, M Mar; Sandoval-Sierra, José Vladimir; Machordom, Annie; Diéguez-Uribeondo, Javier
Emerging fungal diseases are threatening ecosystems and have increased in recent decades. In corals, the prevalence and consequences of these infections have also increased in frequency and severity. Coral reefs are affected by an emerging fungal disease named aspergillosis, caused by Aspergillus sydowii. This disease and its pathogen have been reported along the Caribbean and Pacific coasts of Colombia. Despite this, an important number of coral reefs worldwide have not been investigated for the presence of this pathogen. In this work, we carried out the surveillance of the main coral reef of the Ecuadorian Pacific with a focus on the two most abundant and cosmopolitan species of this ecosystem, Leptogorgia sp. and Leptogorgia obscura. We collected 59 isolates and obtained the corresponding sequences of the Internal Transcribed Spacers (ITS) of the ribosomal DNA. These were phylogenetically analyzed using MrBayes, which indicated the presence of two isolates of the coral reef pathogen A. sydowii, as well as 16 additional species that are potentially pathogenic to corals. Although the analyzed gorgonian specimens appeared healthy, the presence of these pathogens, especially of A. sydowii, alert us to the potential risk to the health and future survival of the Pacific Ecuadorian coral ecosystem under the current scenario of increasing threats and stressors to coral reefs, such as habitat alterations by humans and global climate change.
da Silva Dantas, Alessandra; Day, Alison; Ikeh, Mélanie; Kos, Iaroslava; Achan, Beatrice; Quinn, Janet
Candida albicans is a major fungal pathogen of humans, causing approximately 400,000 life-threatening systemic infections world-wide each year in severely immunocompromised patients. An important fungicidal mechanism employed by innate immune cells involves the generation of toxic reactive oxygen species (ROS), such as superoxide and hydrogen peroxide. Consequently, there is much interest in the strategies employed by C. albicans to evade the oxidative killing by macrophages and neutrophils. Our understanding of how C. albicans senses and responds to ROS has significantly increased in recent years. Key findings include the observations that hydrogen peroxide triggers the filamentation of this polymorphic fungus and that a superoxide dismutase enzyme with a novel mode of action is expressed at the cell surface of C. albicans. Furthermore, recent studies have indicated that combinations of the chemical stresses generated by phagocytes can actively prevent C. albicans oxidative stress responses through a mechanism termed the stress pathway interference. In this review, we present an up-date of our current understanding of the role and regulation of oxidative stress responses in this important human fungal pathogen. PMID:25723552
Amaurys Dávila Martínez
Full Text Available Among the diseases affecting aroids is rhizome rot caused by various pathogen fungi. These rots usually appear in poorly drained heavy soils with high organic matter content. These diseases appear more during the rainy season because it is a fungus complex living in the soil and is favored by high humidity. In order to know the virulence of different pathogens involved in this syndrome, cross-species inoculations were performed. Species of Rhizoctonia solani Kühn and Sclerotiun rolfsii Sacc were used in croos inoculations as they showed a higher percentage of appearance in the analyzed samples. The pathogenicity of the major fungal species was confirmed in Xanthosoma: S. rolfsii, F. sulphureum and F. chlamydosporum and in Colocasia: Phoma sp, Diplodia sp.and S. rolfsii. In the combined inoculations, Rhizoctonia solani showed synergism in the fungus Phoma sp in Xanthosoma and F. chlamydosporum in Colocasia and an antagonistic effect with the rest of the species. S. rolfsii showed synergism with all fungi in Colocasia except with Diplodia sp. and Phoma sp. while in Xanthosoma it showed antagonism with all species.
Jessica L. Chitty
Full Text Available While members of the Kingdom Fungi are found across many of the world’s most hostile environments, only a limited number of species can thrive within the human host. The causative agents of the most common invasive fungal infections are Candida albicans, Aspergillus fumigatus, and Cryptococcus neoformans. During the infection process, these fungi must not only combat the host immune system while adapting to dramatic changes in temperature and pH, but also acquire sufficient nutrients to enable growth and dissemination in the host. One class of nutrients required by fungi, which is found in varying concentrations in their environmental niches and the human host, is the purines. These nitrogen-containing heterocycles are one of the most abundant organic molecules in nature and are required for roles as diverse as signal transduction, energy metabolism and DNA synthesis. The most common life-threatening fungal pathogens can degrade, salvage and synthesize de novo purines through a number of enzymatic steps that are conserved. While these enable them to adapt to the changing purine availability in the environment, only de novo purine biosynthesis is essential during infection and therefore an attractive antimycotic target.
Full Text Available Nowadays, organic food production demands more environmental friendly control of plant diseases. Biocontrol based on Trichoderma spp. usage is a promising due to Trichoderma is aggressive to broad range of phytopathogenic fungi. Given that, the aim of this study was to test in vitro antagonistic ability of ten native Serbian Trichoderma strains to ten common fungal pathogens. Study confirmed that Trichoderma spp. inhibits radial growth of Ascochyta pinodella (76.9%, A. pinodes (60.0%, A. pisi (68.5%, Fusarium graminearum (71.1%, F. proliferatum (63.9%, F. verticillioides (62.6%, F. oxysporum (63.9%, Macrophomina phaseolina (63.8%, and Pyrenophora teres (83.9%. These are first reports of Trichoderma spp. in vitro efficacy against A. pisi, A. pinodes, A. pinodella and P. teres. The lowest inhibitory effect was registered in dual cultures with Sclerotinia sclerotiorum - 52.2%.
Noble, Suzanne M; Johnson, Alexander D
Candida albicans is a species of fungus that typically resides in the gastrointestinal tracts of humans and other warm-blooded animals. It is also the most common human fungal pathogen, causing a variety of skin and soft tissue infections in healthy people and more virulent invasive and disseminated diseases in patients with compromised immune systems. How this microorganism manages to persist in healthy hosts but also to cause a spectrum of disease states in the immunocompromised host are questions of significant biological interest as well as major clinical and economic importance. In this review, we describe recent developments in population genetics, the mating process, and gene disruption technology that are providing much needed experimental insights into the biology of C. albicans.
Ongsri, Punyawee; Bunyaratavej, Sumanas; Leeyaphan, Charussri; Pattanaprichakul, Penvadee; Ongmahutmongkol, Pattachee; Komoltri, Chulaluk; Kulthanan, Kanokvalai
Superficial fungal foot infection is one of the most important dermatological diseases currently affecting military personnel. Many Thai naval rating cadets are found to suffer from superficial fungal foot infections and their sequels. To investigate prevalence, potent risk factors, responding pathogens and clinical correlation of superficial fungal foot infection in Thai naval rating cadets training in Naval rating school, Sattahip, Thailand. This cross-sectional study was performed in August 2015. Validated structured questionnaire was used regarding information about behaviors and clinical symptoms. Quality of life was assessed by Dermatology Quality of Life Index (DLQI) questionnaire and clinical presentation demonstrated by Athlete's foot severity score (AFSS). Laboratory investigations including direct microscopic examination and fungal culture were performed and recorded. All of the participants were informed and asked for their consent. A total of 788 Thai naval rating cadets with a mean age of 19 yr were enrolled. There were 406 (51.5%) participants suspected of fungal skin infection from questionnaire screening. After clinical examination, 303 participants (38.5%) were found to have foot lesions (AFSS ≥1). Superficial fungal foot infection was diagnosed with microscopic examination and fungal culture in 57 participants, giving a point prevalence of 7.2%. Tinea pedis was diagnosed in 54 participants with the leading causative organism being Trichophyton mentagrophytes (52.8%). Other 3 participants were diagnosed as cutaneous candidiasis. Wearing combat shoes more than 8 h was found to be a predisposing factor (p = 0.029), taking a shower less than two times a day (p = 0.008), and wearing sandals during shower (p = 0.055) was found to be protective against infection. Most fungal feet infection cases noticed their feet abnormalities (p < 0.001) including scales (p < 0.001), vesicles (p = 0.003) and maceration at interdigital web spaces (p < 0.001). Mean
Forty-five skin specimens were collected from eight Hospitals in Ihiala Local Government Area, Anambra State, Nigeria to determine the prevalence of fungal organisms associated with skin infections in the area. The samples were treated with potassium hydroxide and examined under the microscope, and cultured on ...
KEY WORDS: Salinity Effect, Bioremediation, Fungal Prevalence, Crude Oil Polluted Soil. INTRODUCTION ... of Science, 1985) in marine and land ..... Marine. Pollution. (4th edition). Oxford University. Press Inc. N. Y. 161p. Day, P. R., 1965. Particles Grain Size Analysis in. CA Black et al (eds) Methods of Soil. Analysis.
Martins Natalia F
Full Text Available Abstract Background The prevalence of invasive fungal infections (IFIs has increased steadily worldwide in the last few decades. Particularly, there has been a global rise in the number of infections among immunosuppressed people. These patients present severe clinical forms of the infections, which are commonly fatal, and they are more susceptible to opportunistic fungal infections than non-immunocompromised people. IFIs have historically been associated with high morbidity and mortality, partly because of the limitations of available antifungal therapies, including side effects, toxicities, drug interactions and antifungal resistance. Thus, the search for alternative therapies and/or the development of more specific drugs is a challenge that needs to be met. Genomics has created new ways of examining genes, which open new strategies for drug development and control of human diseases. Results In silico analyses and manual mining selected initially 57 potential drug targets, based on 55 genes experimentally confirmed as essential for Candida albicans or Aspergillus fumigatus and other 2 genes (kre2 and erg6 relevant for fungal survival within the host. Orthologs for those 57 potential targets were also identified in eight human fungal pathogens (C. albicans, A. fumigatus, Blastomyces dermatitidis, Paracoccidioides brasiliensis, Paracoccidioides lutzii, Coccidioides immitis, Cryptococcus neoformans and Histoplasma capsulatum. Of those, 10 genes were present in all pathogenic fungi analyzed and absent in the human genome. We focused on four candidates: trr1 that encodes for thioredoxin reductase, rim8 that encodes for a protein involved in the proteolytic activation of a transcriptional factor in response to alkaline pH, kre2 that encodes for α-1,2-mannosyltransferase and erg6 that encodes for Δ(24-sterol C-methyltransferase. Conclusions Our data show that the comparative genomics analysis of eight fungal pathogens enabled the identification of
Jullie M Sarmiento-Ramírez
Full Text Available Nascent fungal infections are currently considered as one of the main threats for biodiversity and ecosystem health, and have driven several animal species into critical risk of extinction. Sea turtles are one of the most endangered groups of animals and only seven species have survived to date. Here, we described two pathogenic species, i.e., Fusarium falciforme and Fusarium keratoplasticum, that are globally distributed in major turtle nesting areas for six sea turtle species and that are implicated in low hatch success. These two fungi possess key biological features that are similar to emerging pathogens leading to host extinction, e.g., high virulence, and a broad host range style of life. Their optimal growth temperature overlap with the optimal incubation temperature for eggs, and they are able to kill up to 90% of the embryos. Environmental forcing, e.g., tidal inundation and clay/silt content of nests, were correlated to disease development. Thus, these Fusarium species constitute a major threat to sea turtle nests, especially to those experiencing environmental stressors. These findings have serious implications for the survival of endangered sea turtle populations and the success of conservation programs worldwide.
Franklinos, Lydia H. V.; Lorch, Jeffrey M.; Bohuski, Elizabeth A.; Rodriguez-Ramos Fernandez, Julia; Wright, Owen; Fitzpatrick, Liam; Petrovan, Silviu; Durrant, Chris; Linton, Chris; Baláž, Vojtech; Cunningham, Andrew A; Lawson, Becki
Snake fungal disease (SFD) is an emerging disease of conservation concern in eastern North America. Ophidiomyces ophiodiicola, the causative agent of SFD, has been isolated from over 30 species of wild snakes from six families in North America. Whilst O. ophiodiicola has been isolated from captive snakes outside North America, the pathogen has not been reported from wild snakes elsewhere. We screened 33 carcasses and 303 moulted skins from wild snakes collected from 2010–2016 in Great Britain and the Czech Republic for the presence of macroscopic skin lesions and O. ophiodiicola. The fungus was detected using real-time PCR in 26 (8.6%) specimens across the period of collection. Follow up culture and histopathologic analyses confirmed that both O. ophiodiicola and SFD occur in wild European snakes. Although skin lesions were mild in most cases, in some snakes they were severe and were considered likely to have contributed to mortality. Culture characterisations demonstrated that European isolates grew more slowly than those from the United States, and phylogenetic analyses indicated that isolates from European wild snakes reside in a clade distinct from the North American isolates examined. These genetic and phenotypic differences indicate that the European isolates represent novel strains of O. ophiodiicola. Further work is required to understand the individual and population level impact of this pathogen in Europe.
Zampieri, Elisa; Giordano, Luana; Lione, Guglielmo; Vizzini, Alfredo; Sillo, Fabiano; Balestrini, Raffaella; Gonthier, Paolo
The effects of plant symbionts on host defence responses against pathogens have been extensively documented, but little is known about the impact of pathogens on the symbiosis and if such an impact may differ for nonnative and native pathogens. Here, this issue was addressed in a study of the model system comprising Pinus pinea, its ectomycorrhizal symbiont Tuber borchii, and the nonnative and native pathogens Heterobasidion irregulare and Heterobasidion annosum, respectively. In a 6-month inoculation experiment and using both in planta and gene expression analyses, we tested the hypothesis that H. irregulare has greater effects on the symbiosis than H. annosum. Although the two pathogens induced the same morphological reaction in the plant-symbiont complex, with mycorrhizal density increasing exponentially with pathogen colonization of the host, the number of target genes regulated in T. borchii in plants inoculated with the native pathogen (i.e. 67% of tested genes) was more than twice that in plants inoculated with the nonnative pathogen (i.e. 27% of genes). Although the two fungal pathogens did not differentially affect the amount of ectomycorrhizas, the fungal symbiont perceived their presence differently. The results may suggest that the symbiont has the ability to recognize a self/native and a nonself/nonnative pathogen, probably through host plant-mediated signal transduction. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.
Penn, Cory D; Daniel, Steven L
The fungal plant pathogen Sclerotinia sclerotiorum was studied to determine its ability to degrade salicylate, an important defense-signaling molecule in plants. S. sclerotiorum D-E7 was grown at 25 °C in an undefined medium (50 ml) containing minerals, 0.1% soytone, 50 mM MES buffer (pH 6.5), 25 mM glucose, and 1 mM salicylate. Glucose, oxalate, and salicylate concentrations were monitored by HPLC. S. sclerotiorum D-E7 was found to be active in salicylate degradation. However, salicylate alone was not growth supportive and, at higher levels (10 mM), inhibited glucose-dependent growth. Biomass formation (130 mg [dry wt] of mycelium per 50 ml of undefined medium), oxalate concentrations (~10 mM), and culture acidification (final culture pH approximated 5) were essentially the same in cultures grown with or without salicylate (1 mM). Time-course analyses revealed that salicylate degradation and glucose consumption were complete after 7 days of incubation and was concomitant with growth. Trace amounts of catechol, a known intermediate of salicylate metabolism, were detected during salicylate degradation. Overall, these results indicated that S. sclerotiorum has the ability to degrade salicylate and that the presence of low levels of salicylate did not affect growth or oxalate production by S. sclerotiorum.
Hasan, Nor'Aishah; Rafii, Mohd Y.; Rahim, Harun A.; Ali, Nusaibah Syd; Mazlan, Norida; Abdullah, Shamsiah
Rice is arguably the most crucial food crops supplying quarter of calories intake. Fungal pathogen, Magnaphorthe oryzae promotes blast disease unconditionally to gramineous host including rice species. This disease spurred an outbreaks and constant threat to cereal production. Global rice yield declining almost 10-30% including Malaysia. As Magnaphorthe oryzae and its host is model in disease plant study, the rice blast pathosystem has been the subject of intense interest to overcome the importance of the disease to world agriculture. Therefore, in this study, our prime objective was to isolate samples of Magnaphorthe oryzae from diseased leaf obtained from MARDI Seberang Perai, Penang, Malaysia. Molecular identification was performed by sequences analysis from internal transcribed spacer (ITS) region of nuclear ribosomal RNA genes. Phylogenetic affiliation of the isolated samples were analyzed by comparing the ITS sequences with those deposited in the GenBank database. The sequence of the isolate demonstrated at least 99% nucleotide identity with the corresponding sequence in GenBank for Magnaphorthe oryzae. Morphological observed under microscope demonstrated that the structure of conidia followed similar characteristic as M. oryzae. Finding in this study provide useful information for breeding programs, epidemiology studies and improved disease management.
da Silva, Bianca Alcântara; dos Santos, André Luis Souza; Barreto-Bergter, Eliana; Pinto, Marcia Ribeiro
Pseudallescheria boydii is a ubiquitous filamentous fungus capable of causing invasive disease in humans. In the present study, using sodium dodecyl sulfate-polyacrylamide gels containing bovine serum albumin as co-polymerized substrate, we identified a 28-kDa proteolytic activity released to the extracellular environment by mycelia of P. boydii. This peptidase was detected during the growth of P. boydii in Sabouraud-dextrose medium for 13 days and reached its maximal production on day 7. The 28-kDa peptidase was active in acidic pH (5.5) and had its activity completely blocked by 1,10-phenanthroline, a potent zinc-metallopeptidase inhibitor. Two other metallopeptidase inhibitors, EDTA and EGTA, were also tested and no alterations were observed in the activity of the 28-kDa extracellular peptidase. Likewise, E-64 (a cysteine peptidase inhibitor), phenylmethylsulphonyl fluoride (a serine peptidase inhibitor), and pepstatin A (an aspartyl peptidase inhibitor) did not significantly alter the enzymatic behavior. Collectively, we described for the first time the expression of an extracellular metallopeptidase in the human opportunistic fungal pathogen P. boydii.
Hasan, Nor’Aishah; Rafii, Mohd Y.; Rahim, Harun A.; Ali, Nusaibah Syd; Mazlan, Norida; Abdullah, Shamsiah
Rice is arguably the most crucial food crops supplying quarter of calories intake. Fungal pathogen, Magnaphorthe oryzae promotes blast disease unconditionally to gramineous host including rice species. This disease spurred an outbreaks and constant threat to cereal production. Global rice yield declining almost 10-30% including Malaysia. As Magnaphorthe oryzae and its host is model in disease plant study, the rice blast pathosystem has been the subject of intense interest to overcome the importance of the disease to world agriculture. Therefore, in this study, our prime objective was to isolate samples of Magnaphorthe oryzae from diseased leaf obtained from MARDI Seberang Perai, Penang, Malaysia. Molecular identification was performed by sequences analysis from internal transcribed spacer (ITS) region of nuclear ribosomal RNA genes. Phylogenetic affiliation of the isolated samples were analyzed by comparing the ITS sequences with those deposited in the GenBank database. The sequence of the isolate demonstrated at least 99% nucleotide identity with the corresponding sequence in GenBank for Magnaphorthe oryzae. Morphological observed under microscope demonstrated that the structure of conidia followed similar characteristic as M. oryzae. Finding in this study provide useful information for breeding programs, epidemiology studies and improved disease management
Chernin, L; Ismailov, Z; Haran, S; Chet, I
Three Enterobacter agglomerans strains which produce and excrete proteins with chitinolytic activity were found while screening soil-borne bacteria antagonistic to fungal plant pathogens. The chitinolytic activity was induced when the strains were grown in the presence of colloidal chitin as the sole carbon source. It was quantitated by using assays with chromogenic p-nitrophenyl analogs of disaccharide, trisaccharide, and tetrasaccharide derivatives of N-acetylglucosamine. A set of three fluorescent substrates with a 4-methylumbelliferyl group linked by (beta)-1,4 linkage to N-acetylglucosamine mono- or oligosaccharides were used to identify the chitinolytic activities of proteins which had been renatured following their separation by electrophoresis. This study provides the most complete evidence for the presence of a complex of chitinolytic enzymes in Enterobacter strains. Four enzymes were detected: two N-acetyl-(beta)-d-glucosaminidases of 89 and 67 kDa, an endochitinase with an apparent molecular mass of 59 kDa, and a chitobiosidase of 50 kDa. The biocontrol ability of the chitinolytic strains was demonstrated under greenhouse conditions. The bacteria decreased the incidence of disease caused by Rhizoctonia solani in cotton by 64 to 86%. Two Tn5 mutants of one of the isolates, which were deficient in chitinolytic activity, were unable to protect plants against the disease.
Perez-Nadales, Elena; Almeida Nogueira, Maria Filomena; Baldin, Clara; Castanheira, Sónia; El Ghalid, Mennat; Grund, Elisabeth; Lengeler, Klaus; Marchegiani, Elisabetta; Mehrotra, Pankaj Vinod; Moretti, Marino; Naik, Vikram; Oses-Ruiz, Miriam; Oskarsson, Therese; Schäfer, Katja; Wasserstrom, Lisa
Fungi have the capacity to cause devastating diseases of both plants and animals, causing significant harvest losses that threaten food security and human mycoses with high mortality rates. As a consequence, there is a critical need to promote development of new antifungal drugs, which requires a comprehensive molecular knowledge of fungal pathogenesis. In this review, we critically evaluate current knowledge of seven fungal organisms used as major research models for fungal pathogenesis. The...
Background: Plant fungal pathogens play a crucial role in the profitability, quality and quantity of plant production. These phytopathogens are persistent in avoiding plant defences causing diseases and quality losses around the world that amount to billions of US dollars annually. To control the scourge of plant fungal ...
Chitin is a homopolymer of N-acetyl-d-glucosamine (GlcNAc)that is abundantly present in nature and found as a major structural component in the fungal cell wall. In Chapter 1,the role of chitin as an important factor in the interaction between fungal pathogens and their
Nicolaisen, Mogens; West, Jonathan S.; Sapkota, Rumakanta; Canning, Gail G.M.; Schoen, Cor; Justesen, Annemarie F.
Information on the diversity of fungal spores in air is limited, and also the content of airborne spores of fungal plant pathogens is understudied. In the present study, a total of 152 air samples were taken from rooftops at urban settings in Slagelse, DK, Wageningen NL, and Rothamsted, UK together
Shuping, D.S.S.; Eloff, J.N.
Background: Plant fungal pathogens play a crucial role in the profitability, quality and quantity of plant production. These phytopathogens are persistent in avoiding plant defences causing diseases and quality losses around the world that amount to billions of US dollars annually. To control the scourge of plant fungal diseases, farmers have used fungicides to manage the damage of plant pathogenic fungi. Drawbacks such as development of resistance and environmental toxicity associated with t...
Wan, Jinrong; Stacey, Gary; Stacey, Minviluz; Zhang, Xuecheng
Perception of chitin fragments (chitooligosaccharides) is an important first step in plant defense response against fungal pathogen. LysM receptor-like kinases (LysM RLKs) are instrumental in this perception process. LysM RLKs also play a role in activating transcription of chitin-responsive genes (CRGs) in plants. Mutations in the LysM kinase receptor genes or the downstream CRGs may affect the fungal susceptibility of a plant. Mutations in LysM RLKs or transgenes carrying the same may be beneficial in imparting resistance against fungal pathogens.
Wan, Jinrong [Columbia, MO; Stacey, Gary [Columbia, MO; Stacey, Minviluz [Columbia, MO; Zhang, Xuecheng [Columbia, MO
Perception of chitin fragments (chitooligosaccharides) is an important first step in plant defense response against fungal pathogen. LysM receptor-like kinases (LysM RLKs) are instrumental in this perception process. LysM RLKs also play a role in activating transcription of chitin-responsive genes (CRGs) in plants. Mutations in the LysM kinase receptor genes or the downstream CRGs may affect the fungal susceptibility of a plant. Mutations in LysM RLKs or transgenes carrying the same may be beneficial in imparting resistance against fungal pathogens.
Shuping, D S S; Eloff, J N
Plant fungal pathogens play a crucial role in the profitability, quality and quantity of plant production. These phytopathogens are persistent in avoiding plant defences causing diseases and quality losses around the world that amount to billions of US dollars annually. To control the scourge of plant fungal diseases, farmers have used fungicides to manage the damage of plant pathogenic fungi. Drawbacks such as development of resistance and environmental toxicity associated with these chemicals have motivated researchers and cultivators to investigate other possibilities. Several databases were accessed to determine work done on protecting plants against plant fungal pathogens with plant extracts using search terms "plant fungal pathogen", "plant extracts" and "phytopathogens". Proposals are made on the best extractants and bioassay techniques to be used. In addition to chemical fungicides, biological agents have been used to deal with plant fungal diseases. There are many examples where plant extracts or plant derived compounds have been used as commercial deterrents of fungi on a large scale in agricultural and horticultural setups. One advantage of this approach is that plant extracts usually contain more than one antifungal compound. Consequently the development of resistance of pathogens may be lower if the different compounds affect a different metabolic process. Plants cultivated using plants extracts may also be marketed as organically produced. Many papers have been published on effective antimicrobial compounds present in plant extracts focusing on applications in human health. More research is required to develop suitable, sustainable, effective, cheaper botanical products that can be used to help overcome the scourge of plant fungal diseases. Scientists who have worked only on using plants to control human and animal fungal pathogens should consider the advantages of focusing on plant fungal pathogens. This approach could not only potentially increase
Full Text Available Information on the diversity of fungal spores in air is limited, and also the content of airborne spores of fungal plant pathogens is understudied. In the present study, a total of 152 air samples were taken from rooftops at urban settings in Slagelse, DK, Wageningen NL, and Rothamsted, UK together with 41 samples from above oilseed rape fields in Rothamsted. Samples were taken during 10-day periods in spring and autumn, each sample representing 1 day of sampling. The fungal content of samples was analyzed by metabarcoding of the fungal internal transcribed sequence 1 (ITS1 and by qPCR for specific fungi. The metabarcoding results demonstrated that season had significant effects on airborne fungal communities. In contrast, location did not have strong effects on the communities, even though locations were separated by up to 900 km. Also, a number of plant pathogens had strikingly similar patterns of abundance at the three locations. Rooftop samples were more diverse than samples taken above fields, probably reflecting greater mixing of air from a range of microenvironments for the rooftop sites. Pathogens that were known to be present in the crop were also found in air samples taken above the field. This paper is one of the first detailed studies of fungal composition in air with the focus on plant pathogens and shows that it is possible to detect a range of pathogens in rooftop air samplers using metabarcoding.
Meyer-Wolfarth, Friederike; Schrader, Stefan; Oldenburg, Elisabeth; Brunotte, Joachim; Weinert, Joachim
In agroecosystems soil-borne fungal plant diseases are major yield-limiting factors which are difficult to control. Fungal plant pathogens, like Fusarium species, survive as a saprophyte in infected tissue like crop residues and endanger the health of the following crop by increasing the infection risk for specific plant diseases. In infected plant organs, these pathogens are able to produce mycotoxins. Mycotoxins like deoxynivalenol (DON) persist during storage, are heat resistant and of major concern for human and animal health after consumption of contaminated food and feed, respectively. Among fungivorous soil organisms, there are representatives of the soil fauna which are obviously antagonistic to a Fusarium infection and the contamination with mycotoxins. Specific members of the soil macro-, meso-, and microfauna provide a wide range of ecosystem services including the stimulation of decomposition processes which may result in the regulation of plant pathogens and the degradation of environmental contaminants. Investigations under laboratory conditions and in field were conducted to assess the functional linkage between soil faunal communities and plant pathogenic fungi (Fusarium culmorum). The aim was to examine if Fusarium biomass and the content of its mycotoxin DON decrease substantially in the presence of soil fauna (earthworms: Lumbricus terrestris, collembolans: Folsomia candida and nematodes: Aphelenchoides saprophilus) in a commercial cropping system managed with conservation tillage located in Northern Germany. The results of our investigations pointed out that the degradation performance of the introduced soil fauna must be considered as an important contribution to the biodegradation of fungal plant diseases and fungal-related contaminants. Different size classes within functional groups and the traits of keystone species appear to be significant for soil function and the provision of ecosystem services as in particular L. terrestris revealed to
Jonah Piovia-Scott; Karen Pope; S. Joy Worth; Erica Bree Rosenblum; Dean Simon; Gordon Warburton; Louise A. Rollins-Smith; Laura K. Reinert; Heather L. Wells; Dan Rejmanek; Sharon Lawler; Janet Foley
The fungal pathogen Batrachochytrium dendrobatidis (Bd) has caused declines and extinctions in amphibians worldwide, and there is increasing evidence that some strains of this pathogen are more virulent than others. While a number of putative virulence factors have been identified, few studies link these factors to specific epizootic events. We...
Ohkura, Mana; Fitak, Robert R; Wisecaver, Jennifer H; DeBlasio, Dan; Niazi, Faheem; Egholm, Michael; Rounsley, Steven D; Kodira, Chinnappa D; Orbach, Marc J
Ophidiomyces ophiodiicola , which belongs to the order Onygenales , is an emerging fungal pathogen of snakes in the United States. This study reports the 21.9-Mb genome sequence of an isolate of this reptilian pathogen obtained from a black racer snake in Pennsylvania. Copyright © 2017 Ohkura et al.
Managed honey bee (Apis mellifera) populations are currently facing unsustainable losses due to a variety of factors. Colonies are challenged with brood pathogens, such as the fungal agent of chalkbrood disease, the microsporidian gut parasite Nosema sp., and several viruses. These pathogens may be ...
Jonathan M. Palmer; Kevin P. Drees; Jeffrey T. Foster; Daniel L. Lindner
Bat white-nose syndrome (WNS), caused by the fungal pathogen Pseudogymnoascus destructans, has decimated North American hibernating bats since its emergence in 2006. Here, we utilize comparative genomics to examine the evolutionary history of this pathogen in comparison to six closely related nonpathogenic species....
d'Ovidio, D; Grable, S L; Ferrara, M; Santoro, D
Guinea pigs have been indicated as a potential source of zoophilic dermatophytes that cause human dermatomycosis. The purpose of this study was to evaluate the prevalence of dermatophytes as well as saprophytic fungi in asymptomatic pet guinea pigs in Southern Italy. Two-hundred pet guinea pigs were enrolled from both private veterinary clinics and pet shops in the Campania region, Italy, from August 2012 to September 2013. Samples were collected using the MacKenzie's toothbrush technique. The plates were incubated for four weeks at 25°C and identification of the fungal colonies was based on both macroscopic and microscopic characteristics. Two pathogenic dermatophytes were isolated in 9 (4·5%) of 200 guinea pigs; Epidermophyton species in 2 (1%) and Scopulariopsis species in 7 (3·5%). Saprophytic dermatophytes were isolated from 151 (75·5%) animals enrolled. No fungal growth was observed in 40 (20%) guinea pigs. The results of this study indicate a low prevalence of pathogenic dermatophytes in pet guinea pigs in Southern Italy but the presence of Epidermophyton and Scopulariopsis species in asymptomatic pet guinea pigs. © 2014 British Small Animal Veterinary Association.
Rodolphe Elie Gozlan
Full Text Available Despite increasingly sophisticated microbiological techniques, and long after the first discovery of microbes, basic knowledge is still lacking to fully appreciate the ecological importance of microbial parasites in fish. This is likely due to the nature of their habitats as many species of fish suffer from living beneath turbid water away from easy recording. However, fishes represent key ecosystem services for millions of people around the world and the absence of a functional ecological understanding of viruses, prokaryotes, and small eukaryotes in the maintenance of fish populations and of their diversity represents an inherent barrier to aquatic conservation and food security. Among recent emerging infectious diseases responsible for severe population declines in plant and animal taxa, fungal and fungal-like microbes have emerged as significant contributors. Here, we review the current knowledge gaps of fungal and fungal-like parasites and pathogens in fish and put them into an ecological perspective with direct implications for the monitoring of fungal fish pathogens in the wild, their phylogeography as well as their associated ecological impact on fish populations. With increasing fish movement around the world for farming, releases into the wild for sport fishing and human-driven habitat changes, it is expected, along with improved environmental monitoring of fungal and fungal-like infections, that the full extent of the impact of these pathogens on wild fish populations will soon emerge as a major threat to freshwater biodiversity.
Stukenbrock, Eva H
Hybridization in fungi has recently been recognized as a major force in the generation of new fungal plant pathogens. These include the grass pathogen Zymoseptoria pseudotritici and the powdery mildew pathogen Blumeria graminis triticale of triticale. Hybridization also plays an important role in the transfer of genetic material between species. This process is termed introgressive hybridization and involves extensive backcrossing between hybrid and the parental species. Introgressive hybridization has contributed substantially to the successful spread of plant pathogens such as Ophiostoma ulmi and O. novo-ulmi, the causal agents of Dutch elm disease, and other tree pathogens such as the rust pathogen Melampsora. Hybridization occurs more readily between species that have previously not coexisted, so-called allopatric species. Reproductive barriers between allopatric species are likely to be more permissive allowing interspecific mating to occur. The bringing together of allopatric species of plant pathogens by global agricultural trade consequently increases the potential for hybridization between pathogen species. In light of global environmental changes, agricultural development, and the facilitated long-distance spread of fungal plant pathogens, hybridization should be considered an important mechanism whereby new pathogens may emerge. Recent studies have gained insight into the genetics and biology of fungal hybrids. Here I summarize current knowledge about hybrid speciation and introgressive hybridization. I propose that future studies will benefit greatly from the availability of large genome data sets and that genome data provide a powerful resource in combination with experimental approaches for analyses of hybrid species.
Zhang, Tao; Zhao, Yun-Long; Zhao, Jian-Hua; Wang, Sheng; Jin, Yun; Chen, Zhong-Qi; Fang, Yuan-Yuan; Hua, Chen-Lei; Ding, Shou-Wei; Guo, Hui-Shan
Plant pathogenic fungi represent the largest group of disease-causing agents on crop plants, and are a constant and major threat to agriculture worldwide. Recent studies have shown that engineered production of RNA interference (RNAi)-inducing dsRNA in host plants can trigger specific fungal gene silencing and confer resistance to fungal pathogens 1-7 . Although these findings illustrate efficient uptake of host RNAi triggers by pathogenic fungi, it is unknown whether or not such an uptake mechanism has been evolved for a natural biological function in fungus-host interactions. Here, we show that in response to infection with Verticillium dahliae (a vascular fungal pathogen responsible for devastating wilt diseases in many crops) cotton plants increase production of microRNA 166 (miR166) and miR159 and export both to the fungal hyphae for specific silencing. We found that two V. dahliae genes encoding a Ca 2+ -dependent cysteine protease (Clp-1) and an isotrichodermin C-15 hydroxylase (HiC-15), and targeted by miR166 and miR159, respectively, are both essential for fungal virulence. Notably, V. dahliae strains expressing either Clp-1 or HiC-15 rendered resistant to the respective miRNA exhibited drastically enhanced virulence in cotton plants. Together, our findings identify a novel defence strategy of host plants by exporting specific miRNAs to induce cross-kingdom gene silencing in pathogenic fungi and confer disease resistance.
Shehata, H R; Lyons, E M; Jordan, K S; Raizada, M N
The aim of this study was to determine if endophytes from wild and ancient Zea plants (corn family) have anti-fungal activities, specifically against the most important fungal pathogen (Sclerotinia homoeocarpa) of creeping bentgrass, a relative of Zea, used here as a model grass. A library of 190 bacterial endophytes from wild, ancient and modern Zea plants were tested for their ability to suppress S. homoeocarpa in vitro, followed by in planta testing of candidates using greenhouse trials. Three endophytes could suppress S. homoeocarpa, originating from wild maize and an ancient Mexican landrace, consistent with our hypothesis. 16S phylogenetic analysis and BOX-PCR DNA fingerprinting suggest that the anti-fungal endophytes are distinct strains of Burkholderia gladioli. One strain (3A12) was confirmed to colonize creeping bentgrass using green fluorescent protein (GFP) tagging. Evans blue vitality staining demonstrated that the bacterial endophytes exhibited fungicidal activities against the pathogen. The endophytes inhibited a wide spectrum of plant-associated fungi including diverse crop pathogens. The results support the hypothesis that wild and ancient Zea genotypes host bacterial endophytes that can control fungal pathogen(s). These results suggest that wild and ancient crops may be an unexplored reservoir of anti-fungal bacterial endophytes. © 2016 The Society for Applied Microbiology.
Full Text Available The ascomycete fungus Fusarium graminearum is a major causal agent for Fusarium head blight in cereals and produces mycotoxins such as trichothecenes and zearalenone. Isolation of the fungal strains from air or cereals can be hampered by various other airborne fungal pathogens and saprophytic fungi. In this study, we developed a selective medium specific to F. graminearum using toxoflavin produced by the bacterial pathogen Burkholderia glumae. F. graminearum was resistant to toxoflavin, while other fungi were sensitive to this toxin. Supplementing toxoflavin into medium enhanced the isolation of F. graminearum from rice grains by suppressing the growth of saprophytic fungal species. In addition, a medium with or without toxoflavin exposed to wheat fields for 1 h had 84% or 25%, respectively, of colonies identified as F. graminearum. This selection medium provides an efficient tool for isolating F. graminearum, and can be adopted by research groups working on genetics and disease forecasting.
Kadioğlu, I; Karamanli, N; Yanar, Y
This study was carried out to determine the fungal pathogens on Chenopodium album L., Cirsium arvense (L.) Scop., Convolvulus arvensis L., Cynodon dactylon (L.) Pers., Delphinium consolida L., Portulaca oleracea L., Rumex crispus L., Solanum nigrum L., Sorghum halepense (L.) Pers. and Xanthium strumarium L. which were common weed species of agricultural areas. Surveys were conducted in May-June and August-September in 2004-2005 growing seasons. During the surveys density and frequency of the above mentioned weed species were also determined and number of infected plants was counted in each sampling area. Infected weed samples were collected from each sampling point and brought to the laboratory in polyethylene bags and the pathogens were identified at genus or species level. As a result of two year surveys, ten fungal pathogens were determined on eight weed species. The most important fungal pathogens determined on common weed species were as follow; Peronospora farinosa (Fr.) Fr. on C. album, and Septoria convolvuli DC., Erysiphe convolvuli DC., and Puccinia punctiformis (Strauss) Roehrl. on C. arvensis. These fungal diseases were observed mainly on the weeds located at the borders of fields. Infection rates of these pathogens reached up to 21.2% in some of the survey areas. Further studies should be conducted to evaluate the efficacy of these pathogen under in vitro and in vivo conditions.
Aliouat-Denis, Cécile-Marie; Chabé, Magali; Delhaes, Laurence; Dei-Cas, Eduardo
In the last few decades, aerially transmitted human fungal pathogens have been increasingly recognized to impact the clinical course of chronic pulmonary diseases, such as asthma, cystic fibrosis or chronic obstructive pulmonary disease. Thanks to recent development of culture-free high-throughput sequencing methods, the metagenomic approaches are now appropriate to detect, identify and even quantify prokaryotic or eukaryotic microorganism communities inhabiting human respiratory tract and to access the complexity of even low-burden microbe communities that are likely to play a role in chronic pulmonary diseases. In this review, we explore how metagenomics and comparative genomics studies can alleviate fungal culture bottlenecks, improve our knowledge about fungal biology, lift the veil on cross-talks between host lung and fungal microbiota, and gain insights into the pathogenic impact of these aerially transmitted fungi that affect human beings. We reviewed metagenomic studies and comparative genomic analyses of carefully chosen microorganisms, and confirmed the usefulness of such approaches to better delineate biology and pathogenesis of aerially transmitted human fungal pathogens. Efforts to generate and efficiently analyze the enormous amount of data produced by such novel approaches have to be pursued, and will potentially provide the patients suffering from chronic pulmonary diseases with a better management. This manuscript is part of the series of works presented at the "V International Workshop: Molecular genetic approaches to the study of human pathogenic fungi" (Oaxaca, Mexico, 2012). Copyright © 2013 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.
Grison, R.; Grezes-Besset, B.; Lucante, N. [Rustica Prograin Genetique, Mondonville (France)] [and others
Constitutive overexpression of a protein involved in plant defense mechanisms to disease is one of the strategies proposed to increase plant tolerance to fungal pathogens. A hybrid endochitinase gene under a constitutive promoter was introduced by Agrobacterium-mediated transformation into a winter-type oilseed rape (Brassica napus var. oleifera) inbred line. Progeny from transformed plants was challenged using three different fungal pathogens (Cylindrosporium concentricum, Phoma lingam, Sclerotinia sclerotiorum) in field trials at two different geographical locations. These plants exhibited an increased tolerance to disease as compared with the nontransgenic parental plants. 31 refs., 1 fig., 2 tabs.
García-Guzmán, Graciela; Heil, Martin
Plant pathogens affect the fitness of their hosts and maintain biodiversity. However, we lack theories to predict the type and intensity of infections in wild plants. Here we demonstrate using fungal pathogens of tropical plants that an examination of the life histories of hosts and pathogens can reveal general patterns in their interactions. Fungal infections were more commonly reported for light-demanding than for shade-tolerant species and for evergreen rather than for deciduous hosts. Both patterns are consistent with classical defence theory, which predicts lower resistance in fast-growing species and suggests that the deciduous habit can reduce enemy populations. In our literature survey, necrotrophs were found mainly to infect shade-tolerant woody species whereas biotrophs dominated in light-demanding herbaceous hosts. Far-red signalling and its inhibitory effects on jasmonic acid signalling are likely to explain this phenomenon. Multiple changes between the necrotrophic and the symptomless endophytic lifestyle at the ecological and evolutionary scale indicate that endophytes should be considered when trying to understand large-scale patterns in the fungal infections of plants. Combining knowledge about the molecular mechanisms of pathogen resistance with classical defence theory enables the formulation of testable predictions concerning general patterns in the infections of wild plants by fungal pathogens. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.
Warpeha, Katherine M; Park, Yoon-Dong; Williamson, Peter R
The fungus Cryptococcus contributes a large global burden of infectious death in both HIV-infected and healthy individuals. As Cryptococcus is an opportunistic pathogen, much of the evolutionary pressure shaping virulence occurs in environments in contact with plants and soil. The present studies investigated inoculation of intact seeds of the common weed Arabidopsis thaliana with fungal cells over a 21-day period. C. gattii was the more virulent plant pathogen, resulting in disrupted germination as well as increased stem lodging, fungal burden, and plant tissue colocalization. C. neoformans was a less virulent plant pathogen but exhibited prolonged tissue residence within the cuticle and vascular spaces. Arabidopsis mutants of the PRN1 gene, which is involved in abiotic and biotic signaling affecting phenylalanine-derived flavonoids, showed altered susceptibility to cryptoccocal infections, suggesting roles for this pathway in cryptococcal defense. The fungal virulence factor laccase was also implicated in plant pathogenesis, as a cryptococcal lac1Δ strain was less virulent than wild-type fungi and was unable to colonize seedlings. In conclusion, these studies expand knowledge concerning the ecological niche of Cryptococcus by demonstrating the pathogenic capacity of the anamorphic form of cryptococcal cells against healthy seedlings under physiologically relevant conditions. In addition, an important role of laccase in plant as well as human virulence may suggest mechanisms for laccase retention and optimization during evolution of this fungal pathogen.
Bourgeois, Christelle; Kuchler, Karl
Hundred-thousands of fungal species are present in our environment, including normal colonizers that constitute part of the human microbiota. The homeostasis of host-fungus interactions encompasses efficient fungal sensing, tolerance at mucosal surfaces, as well as antifungal defenses. Decrease in host immune fitness or increase in fungal burden may favor pathologies, ranging from superficial mucocutaneous diseases to invasive life-threatening fungal infections. Toll-like receptors (TLRs) are essential players in this balance, due to their ability to control both inflammatory and anti-inflammatory processes upon recognition of fungal-specific pathogen-associated molecular patterns (PAMPs). Certain members of the TLR family participate to the initial recognition of fungal PAMPs on the cell surface, as well as inside phagosomes of innate immune cells. Active signaling cascades in phagocytes ultimately enable fungus clearance and the release of cytokines that shape and instruct other innate immune cells and the adaptive immune system. Some TLRs cooperate with other pattern recognition receptors (PRRs) (e.g., C-type lectins and Galectins), thus allowing for a tailored immune response. The spatio-temporal and physiological contributions of individual TLRs in fungal infections remains ill-defined, although in humans, TLR gene polymorphisms have been linked to increased susceptibility to fungal infections. This review focuses entirely on the role of TLRs that control the host susceptibility to environmental fungi (e.g., Aspergillus, Cryptoccocus, and Coccidoides), as well as to the most frequent human fungal pathogens represented by the commensal Candida species. The emerging roles of TLRs in modulating host tolerance to fungi, and the strategies that evolved in some of these fungi to evade or use TLR recognition to their advantage will also be discussed, as well as their potential suitability as targets in vaccine therapies.
Amaurys Dávila Martínez; Lidcay Herrera Isla; Maryluz Folgueras Montiel; Ernesto Espinosa Cuellar
Among the diseases affecting aroids is rhizome rot caused by various pathogen fungi. These rots usually appear in poorly drained heavy soils with high organic matter content. These diseases appear more during the rainy season because it is a fungus complex living in the soil and is favored by high humidity. In order to know the virulence of different pathogens involved in this syndrome, cross-species inoculations were performed. Species of Rhizoctonia solani Kühn and Sclerotiun rolfsii Sacc w...
M. Srivastava; S.K. Gupta, A.P. Saxena, L.A.J. Shittu and S.K. Gupta
Brassica vegetables are subjected to viral, bacterial as well as fungal attack, which causes a high yield loss. Temperature and moisture conditions, which promote the growth of fungus, are needed to be studied in order for an effective control of the disease to be estimated. The present review gives a brief account of the fungal diseases which have been considered responsible for major economic loss to the Brassica crops. The epidemiological conditions necessary for the occurrence and prevale...
Telsa Willsey; Telsa Willsey; Syama Chatterton; Héctor Cárcamo
Soilborne fungal and oomycete pathogens are the causal agents of several important plant diseases. Infection frequently co-occurs with herbivory by root-feeding insects, facilitating tripartite interactions that modify plant performance and mortality. In an agricultural context, interactions between pathogens, herbivores, and plants can have important consequences for yield protection. However, belowground interactions are inherently difficult to observe and are often overlooked. Here, we rev...
Muñoz, José F.; Gauthier, Gregory M.; Desjardins, Christopher A.; Gallo, Juan E.; Holder, Jason; Sullivan, Thomas D.; Marty, Amber J.; Carmen, John C.; Chen, Zehua; Ding, Li; Gujja, Sharvari; Magrini, Vincent; Misas, Elizabeth; Mitreva, Makedonka; Priest, Margaret
Three closely related thermally dimorphic pathogens are causal agents of major fungal diseases affecting humans in the Americas: blastomycosis, histoplasmosis and paracoccidioidomycosis. Here we report the genome sequence and analysis of four strains of the etiological agent of blastomycosis, Blastomyces, and two species of the related genus Emmonsia, typically pathogens of small mammals. Compared to related species, Blastomyces genomes are highly expanded, with long, often sharply demarcated...
Oliver, Richard P; Ipcho, Simon V S
SUMMARY Fungal plant pathologists have for many decades attempted to classify pathogens into groups called necrotrophs, biotrophs and, more recently, hemibiotrophs. Although these terms are well known and frequently used, disagreements about which pathogens fall into which classes, as well as the precise definition of these terms, has conspired to limit their usefulness. Dogmas concerning the properties of the classes have been progressively eroded. However, the genetic analysis of disease resistance, particularly in the model plant Arabidopsis thaliana, has provided a biologically meaningful division based on whether defence against fungal pathogens is controlled via the salicylate or jasmonate/ethylene pathways. This mode-of-defence division distinguishes necrotrophs and biotrophs but it limits the biotroph class to pathogens that possess haustoria. The small number and limited range of pathogens that infect Arabidopsis means that several interesting questions are still unanswered. Do hemibiotrophs represents a distinct class or a subclass of the necrotrophs? Does the division apply to other plant families and particularly to cereals? and does this classification help us understand the intricacies of either fungal pathogenicity or plant defence?
Reber, Anabelle; Chapuisat, Michel
There is accumulating evidence that invertebrates can acquire long-term protection against pathogens through immune priming. However, the range of pathogens eliciting immune priming and the specificity of the response remain unclear. Here, we tested if the exposure to a natural fungal pathogen elicited immune priming in ants. We found no evidence for immune priming in Formica selysi workers exposed to Beauveria bassiana. The initial exposure of ants to the fungus did not alter their resistance in a subsequent challenge with the same fungus. There was no sign of priming when using homologous and heterologous combinations of fungal strains for exposure and subsequent challenges at two time intervals. Hence, within the range of conditions tested, the immune response of this social insect to the fungal pathogen appears to lack memory and strain-specificity. These results show that immune priming is not ubiquitous across pathogens, hosts and conditions, possibly because of immune evasion by the pathogen or efficient social defences by the host.
Paul W. Bradley; Stephanie S. Gervasi; Jessica Hua; Rickey D. Cothran; Rick A. Relyea; Deanna H. Olson; Andrew R. Blaustein
Contributing to the worldwide biodiversity crisis are emerging infectious diseases, which can lead to extirpations and extinctions of hosts. For example, the infectious fungal pathogen Batrachochytrium dendrobatidis (Bd) is associated with worldwide amphibian population declines and extinctions. Sensitivity to Bd varies with species, season, and life stage. However,...
Occurrence of seed-borne fungal pathogens in rice seed from the southern highlands of Tanzania. L T H Nsemwa, H Wolffhechel. Abstract. (African Crop Science Journal: 1999 7(2): 217-222). AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...
The most frequently soil-borne fungal pathogens on plants are Fusarium species that make high economical damages in various agricultural locations in Iran. Our studies show that Fusarium species cause significant yield losses in main crops especially potato, pea, bean, wheat, corn and rice in several parts of the country.
Alkan, Noam; Fortes, Ana M.
Due to post-harvest losses more than 30% of harvested fruits will not reach the consumers’ plate. Fungal pathogens play a key role in those losses, as they cause most of the fruit rots and the customer complaints. Many of the fungal pathogens are already present in the unripe fruit but remain quiescent during fruit growth until a particular phase of fruit ripening and senescence. The pathogens sense the developmental change and switch into the devastating necrotrophic life style that causes fruit rotting. Colonization of unripe fruit by the fungus initiates defensive responses that limit fungal growth and development. However, during fruit ripening several physiological processes occur that correlate with increased fruit susceptibility. In contrast to plant defenses in unripe fruit, the defense posture of ripe fruit entails a different subset of defense responses that will end with fruit rotting and losses. This review will focus on several aspects of molecular and metabolic events associated with fleshy fruit responses induced by post-harvest fungal pathogens during fruit ripening. PMID:26539204
Martin, Cara; Roberts, David; van der Weide, Marjo; Rossau, Rudi; Jannes, Geert; Smith, Terry; Maher, Majella
We report on a reverse-hybridization line probe assay (LiPA) which when combined with PCR amplification detects and identifies clinically significant fungal pathogens including Candida, Aspergillus, and Cryptococcus species. DNA probes have been designed from the internal transcribed-spacer (ITS) regions of Candida albicans, Candida parapsilosis, Candida glabrata, Candida tropicalis, Candida krusei, Candida dubliniensis, Cryptococcus neoformans, Aspergillus fumigatus, Aspergillus versicolor, ...
Snoeijers, S.S.; Pérez-García, A.; Joosten, M.H.A.J.; Wit, de P.J.G.M.
Successful colonisation of plants by pathogens requires efficient utilisation of nutrient resources available in host tissues. Several bacterial and fungal genes are specifically induced during pathogenesis and under nitrogen-limiting conditions in vitro. This suggests that a nitrogen-limiting
Ake Olson; Andrea Aerts; Fred Asiegbu; Lassaad Belbahri; Ourdia Bouzid; Anders Broberg; Bjorn Canback; Pedro M. Coutinho; Dan Cullen; Kerstin Dalman; Giuliana Deflorio; Linda T.A. van Diepen; Christophe Dunand; Sebastien Duplessis; Mikael Durling; Paolo Gonthier; Jane Grimwood; Carl Gunnar Fossdal; David Hansson; Bernard Henrissat; Ari Hietala; Kajsa Himmelsrand; Dirk Hoffmeister; Nils Hogberg; Timothy Y. James; Magnus Karlsson; Annegret Kohler; Ursula Kues; Yong-Hwan Lee; Yao-Cheng Lin; Marten Lind; Erika Lindquist; Vincent Lombard; Susan Lucas; Karl Lunden; Emmanuelle Morin; Claude Murat; Jongsun Park; Tommaso Raffaello; Pierre Rouze; Asaf Salamov; Jeremy Schmutz; Halvor Solheim; Jerry Stahlberg; Heriberto Velez; Ronald P. deVries; Ad Wiebenga; Steve Woodward; Igor Yakovlev; Matteo Garbelotto; Francis Martin; Igor V. Grigoriev; Jan. Stenlid
â¢ Parasitism and saprotrophic wood decay are two fungal strategies fundamental for succession and nutrient cycling in forest ecosystems. An opportunity to assess the trade-off between these strategies is provided by the forest pathogen and wood decayer Heterobasidion annosum sensu lato. â¢ We report the annotated genome sequence and transcript...
Abd-Elsalam, K.A.; Yassin, M.A.; Moslem, M.A.; Bahkali, A.H.; Wit, de P.J.G.M.; McKenzie, E.H.C.; Stephenson, S.L.; Cai, L.; Hyde, K.D.
This paper discusses the importance of culture collections in plant pathology and reviews the methods currently available to store cultures. The preservation and maintenance of plant pathogenic fungi in a viable yet stable state for long periods has always been important, because isolates of these
Wit, de P.J.G.M.
Fungi are notorious plant pathogens and continuously threat global food production. In the last decades we have obtained a better understanding of infection strategies of fungi and the plant immune system. This has facilitated more efficient introduction of disease resistance genes in crop plants by
Veerdonk, F.L. van de; Kullberg, B.J.; Meer, J.W.M. van der; Gow, N.A.; Netea, M.G.
The recognition of fungi is mediated by germline pattern recognition receptors (PRRs) such as Toll-like receptors and lectin receptors that interact with conserved structures of the microorganisms, the pathogen-associated molecular patterns (PAMPs). Subsequently, PRRs activate intracellular signals
Full Text Available Fusarium trichothecenes are fungal toxins that cause disease on infected plants and, more importantly, health problems for humans and animals that consume infected fruits or vegetables. Unfortunately, there are few methods for controlling mycotoxin production by fungal pathogens. In this study, we isolated and characterized sixteen Fusarium strains from naturally infected potato plants in the field. Pathogenicity tests were carried out in the greenhouse to evaluate the virulence of the strains on potato plants as well as their trichothecene production capacity, and the most aggressive strain was selected for further studies. This strain, identified as F. sambucinum, was used to determine if trichothecene gene expression was affected by the symbiotic Arbuscular mycorrhizal fungus (AMF Glomus irregulare. AMF form symbioses with plant roots, in particular by improving their mineral nutrient uptake and protecting plants against soil-borne pathogens. We found that that G. irregulare significantly inhibits F. sambucinum growth. We also found, using RT-PCR assays to assess the relative expression of trichothecene genes, that in the presence of the AMF G. irregulare, F. sambucinum genes TRI5 and TRI6 were up-regulated, while TRI4, TRI13 and TRI101 were down-regulated. We conclude that AMF can modulate mycotoxin gene expression by a plant fungal pathogen. This previously undescribed effect may be an important mechanism for biological control and has fascinating implications for advancing our knowledge of plant-microbe interactions and controlling plant pathogens.
Koch, Karrie A; Ragsdale, David W
Since the introduction of soybean aphid, Aphis glycines Matsumura, from Asia, insecticide use in soybean has increased substantially in the north central United States. Insecticide seed treatments and aphid resistant soybean varieties are management tactics that may reduce reliance on foliar applications of broad-spectrum insecticides. Exploring potential nontarget impacts of these technologies will be an important step in incorporating them into aphid management programs. We investigated impacts of thiamethoxam seed treatment and Rag1 aphid resistant soybean on a fungal pathogen of soybean aphid, Pandora neoaphidis (Remaudière & Hennebert) Humber, via open plot and cage studies. We found that although thiamethoxam seed treatment did significantly lower aphid pressure in open plots compared with an untreated control, this reduction in aphid density translated into nonsignificant decreases in fungal disease prevalence in aphids. Furthermore, when aphid densities were approximately equal in seed treated and untreated soybean, no impact on aphid fungal disease was observed. In open plots, Rag1 resistant soybean experienced lower aphid pressure and aphid disease prevalence compared with a nonresistant isoline. However, in cages when aphid densities were equivalent in both resistant and susceptible soybean, resistance had no impact on aphid disease prevalence. The addition of thiamethoxam seed treatment to resistant soybean yielded aphid densities and aphid disease prevalence similar to untreated, resistant soybean. These studies provide evidence that thiamethoxam seed treatments and Rag1 resistance can impact P. neoaphidis via decreased aphid densities; however, this impact is minimal, implying use of seed treatments and host plant resistance are compatible with P. neoaphidis.
Nelson, Berlin D.; Ajayi-Oyetunde, Olutoyosi; Bradley, Carl A.; Hughes, Teresa J.; Hartman, Glen L.; Eastburn, Darin M.
ABSTRACT Mycoviruses can have a marked effect on natural fungal communities and influence plant health and productivity. However, a comprehensive picture of mycoviral diversity is still lacking. To characterize the viromes of five widely dispersed plant-pathogenic fungi, Colletotrichum truncatum, Macrophomina phaseolina, Diaporthe longicolla, Rhizoctonia solani, and Sclerotinia sclerotiorum, a high-throughput sequencing-based metatranscriptomic approach was used to detect viral sequences. Total RNA and double-stranded RNA (dsRNA) from mycelia and RNA from samples enriched for virus particles were sequenced. Sequence data were assembled de novo, and contigs with predicted amino acid sequence similarities to viruses in the nonredundant protein database were selected. The analysis identified 72 partial or complete genome segments representing 66 previously undescribed mycoviruses. Using primers specific for each viral contig, at least one fungal isolate was identified that contained each virus. The novel mycoviruses showed affinity with 15 distinct lineages: Barnaviridae, Benyviridae, Chrysoviridae, Endornaviridae, Fusariviridae, Hypoviridae, Mononegavirales, Narnaviridae, Ophioviridae, Ourmiavirus, Partitiviridae, Tombusviridae, Totiviridae, Tymoviridae, and Virgaviridae. More than half of the viral sequences were predicted to be members of the Mitovirus genus in the family Narnaviridae, which replicate within mitochondria. Five viral sequences showed strong affinity with three families (Benyviridae, Ophioviridae, and Virgaviridae) that previously contained no mycovirus species. The genomic information provides insight into the diversity and taxonomy of mycoviruses and coevolution of mycoviruses and their fungal hosts. IMPORTANCE Plant-pathogenic fungi reduce crop yields, which affects food security worldwide. Plant host resistance is considered a sustainable disease management option but may often be incomplete or lacking for some crops to certain fungal pathogens
Rubol, S.; Turco, E.; Rodeghiero, M.; Bellin, A.
In the last decade, planar optodes have demonstrated to be a useful non-invasive tool to monitor real time oxygen concentrations in a wide range of applications. However, only limited investigations have been carried out to explore the use of optodes in plant respiration studies. In particular, their use to study plant-pathogen interactions has been not deeply investigated. Here, we present for the first time an in vitro experimental setup capable to depict the dynamical effects of the fungal pathogen Fusarium oxysporum f.sp. lycopersici (Fol) on tomato roots by the use of a recently developed optical non-invasive optode oxygen sensor (Visisens, Presens, Germany). Fol is a soil-borne pathogen and the causal agent of wilt in tomato plants, a destructive worldwide disease. The interaction Fol-tomato is widely accepted as a model system in plant pathology. In this work, oxygen concentrations are monitored continuously in time and considered a proxy for root respiration and metabolic activity. The experimental procedure reveals three different dynamic stages: 1) a uniform oxygen consumption in tomato roots earlier before pathogen colonization, 2) a progressive decrease in the oxygen concentration indicating a high metabolic activity as soon as the roots were surrounded and colonized by the fungal mycelium, and 3) absence of root respiration, as a consequence of root death. Our results suggest the ability of the fungal mycelium to move preferentially towards and along the root as a consequence of the recognition event.
Téllez, M D; Batista-Duharte, A; Portuondo, D; Quinello, C; Bonne-Hernández, R; Carlos, I Z
Sporothrix schenckii is a complex of various species of fungus found in soils, plants, decaying vegetables and other outdoor environments. It is the aetiological agent of sporotrichosis in humans and several animals. Humans and animals can acquire the disease through traumatic inoculation of the fungus into subcutaneous tissue. Despite the importance of sporotrichosis, it being currently regarded as an emergent disease in several countries, the factors driving its increasing medical importance are still largely unknown. There have only been a few studies addressing the influence of the environment on the virulence of these pathogens. However, recent studies have demonstrated that adverse conditions in its natural habitats can trigger the expression of different virulence factors that confer survival advantages both in animal hosts and in the environment. In this review, we provide updates on the important advances in the understanding of the biology of Spor. schenckii and the modification of its virulence linked to demonstrated or putative environmental factors. © 2014 The Authors.
Ian Joseph Girard
Full Text Available With a rapidly growing human population it is expected that plant science researchers and the agricultural community will need to increase food productivity using less arable land. This challenge is complicated by fungal pathogens and diseases, many of which can severely impact crop yield. Current measures to control fungal pathogens are either ineffective or have adverse effects on the agricultural enterprise. Thus, developing new strategies through research innovation to protect plants from pathogenic fungi is necessary to overcome these hurdles. RNA sequencing technologies are increasing our understanding of the underlying genes and gene regulatory networks mediating disease outcomes. The application of invigorating next generation sequencing strategies to study plant-pathogen interactions has and will provide unprecedented insight into the complex patterns of gene activity responsible for crop protection. However, questions remain about how biological processes in both the pathogen and the host are specified in space directly at the site of infection and over the infection period. The integration of cutting edge molecular and computational tools will provide plant scientists with the arsenal required to identify genes and molecules that play a role in plant protection. Large scale RNA sequence data can then be used to protect plants by targeting genes essential for pathogen viability in the production of stably transformed lines expressing RNA interference molecules, or through foliar applications of double stranded RNA.
Girard, Ian J; Mcloughlin, Austein G; de Kievit, Teresa R; Fernando, Dilantha W G; Belmonte, Mark F
With a rapidly growing human population it is expected that plant science researchers and the agricultural community will need to increase food productivity using less arable land. This challenge is complicated by fungal pathogens and diseases, many of which can severely impact crop yield. Current measures to control fungal pathogens are either ineffective or have adverse effects on the agricultural enterprise. Thus, developing new strategies through research innovation to protect plants from pathogenic fungi is necessary to overcome these hurdles. RNA sequencing technologies are increasing our understanding of the underlying genes and gene regulatory networks mediating disease outcomes. The application of invigorating next generation sequencing strategies to study plant-pathogen interactions has and will provide unprecedented insight into the complex patterns of gene activity responsible for crop protection. However, questions remain about how biological processes in both the pathogen and the host are specified in space directly at the site of infection and over the infection period. The integration of cutting edge molecular and computational tools will provide plant scientists with the arsenal required to identify genes and molecules that play a role in plant protection. Large scale RNA sequence data can then be used to protect plants by targeting genes essential for pathogen viability in the production of stably transformed lines expressing RNA interference molecules, or through foliar applications of double stranded RNA.
Jiji, T.; Praveena, R.; Babu, Kavitha; Naseema, A.; Anitha, N.
Pathogenicity of the fungi Paecilomyces lilacinus, isolated from Bactrocera cucurbitae, and Aspergillus candidus, isolated from B. dorsalis, was tested. Cross infectivity of P. lilacinus on B. dorsalis and A. candidus on B. cucurbitae and cross infectivity of a local isolate of B. bassiana from bhindi leaf roller (Sylepta derogata) on fruit flies (B. cucurbitae and B. dorsalis ) were also studied. These fungi were new records in these hosts. P. lilacinus at 109 spores / ml caused 96.67% and 100 % cumulative mortality in fruit flies on the second and on the third days. LC50 values of P. lilacinus on B. cucurbitae were 5.0 x 106, 8.0 x 105, 7.0 x 105 spores/ ml on second, third and fourth day, respectively. The fungus was found to cross infect B. dorsalis. LC50 values of A. candidus on B. cucurbitae were 1.29 x 108, 1.22 x 107, 2.27 x 106 spores / ml on third, fourth and fifth day, respectively. The fungus was found to be cross infective to B. cucurbitae. B. bassiana at 109 spores/ ml on B. dorsalis was found to cause 70%, 80% and 90% mortality on fourth, fifth and sixth day. LC50 values of B. bassiana on B. dorsalis were 7.0 x 108, 2.0 x 107, 5.0 x 106 spores/ ml on third, fourth and fifth day ,respectively . Formulation of P. lilacinus as wettable powder and granules and B. bassiana as wettable powder, were also prepared and their efficacy was tested on hosts. (author)
Jiji, T.; Praveena, R.; Babu, Kavitha; Naseema, A.; Anitha, N. [College of Agriculture, Kerala (India)
Pathogenicity of the fungi Paecilomyces lilacinus, isolated from Bactrocera cucurbitae, and Aspergillus candidus, isolated from B. dorsalis, was tested. Cross infectivity of P. lilacinus on B. dorsalis and A. candidus on B. cucurbitae and cross infectivity of a local isolate of B. bassiana from bhindi leaf roller (Sylepta derogata) on fruit flies (B. cucurbitae and B. dorsalis ) were also studied. These fungi were new records in these hosts. P. lilacinus at 109 spores / ml caused 96.67% and 100 % cumulative mortality in fruit flies on the second and on the third days. LC50 values of P. lilacinus on B. cucurbitae were 5.0 x 106, 8.0 x 105, 7.0 x 105 spores/ ml on second, third and fourth day, respectively. The fungus was found to cross infect B. dorsalis. LC50 values of A. candidus on B. cucurbitae were 1.29 x 108, 1.22 x 107, 2.27 x 106 spores / ml on third, fourth and fifth day, respectively. The fungus was found to be cross infective to B. cucurbitae. B. bassiana at 109 spores/ ml on B. dorsalis was found to cause 70%, 80% and 90% mortality on fourth, fifth and sixth day. LC50 values of B. bassiana on B. dorsalis were 7.0 x 108, 2.0 x 107, 5.0 x 106 spores/ ml on third, fourth and fifth day ,respectively . Formulation of P. lilacinus as wettable powder and granules and B. bassiana as wettable powder, were also prepared and their efficacy was tested on hosts. (author)
Fisher, Alison J.
In 2000, three subspecific groupings within the fungal pathogen Claviceps purpurea (Fr.) Tul were discovered. These groups are habitat specialized, where group 1 (G1) is found on terrestrial grasses, G2 is found in freshwater environments and G3 is found in salt marsh habitats. An intraspecific comparison of 43 G3 isolates, seven G1 isolates, and two G2 isolates using random amplified polymorphic DNA (RAPD) and amplified fragment length polymorphism (AFLP) analysis support the recognition of ...
Žabka, Martin; Drastichová, K.; Jegorov, A.; Soukupová, Julie; Nedbal, Ladislav
Roč. 162, č. 1 (2006), s. 65-68 ISSN 0301-486X R&D Projects: GA ČR GA203/04/0799; GA MŠk LN00A141; GA MŠk LC545 Institutional research plan: CEZ:AV0Z50200510; CEZ:AV0Z60870520 Keywords : fluorescence * plant-pathogenic activity * fungal metabolites Subject RIV: EE - Microbiology, Virology Impact factor: 0.915, year: 2006
Full Text Available A fundamental problem in fungal pathogenesis is to elucidate the evolutionary forces responsible for genomic rearrangements leading to races with fitter genotypes. Understanding the adaptive evolutionary mechanisms requires identification of genomic components and environmental factors reshaping the genome of fungal pathogens to adapt. Herein, Magnaporthe oryzae, a model fungal plant pathogen is used to demonstrate the impact of environmental cues on transposable elements (TE based genome dynamics. For heat shock and copper stress exposed samples, eight TEs belonging to class I and II family were employed to obtain DNA profiles. Stress induced mutant bands showed a positive correlation with dose/duration of stress and provided evidences of TEs role in stress adaptiveness. Further, we demonstrate that genome dynamics differ for the type/family of TEs upon stress exposition and previous reports of stress induced MAGGY transposition has underestimated the role of TEs in M. oryzae. Here, we identified Pyret, MAGGY, Pot3, MINE, Mg-SINE, Grasshopper and MGLR3 as contributors of high genomic instability in M. oryzae in respective order. Sequencing of mutated bands led to the identification of LTR-retrotransposon sequences within regulatory regions of psuedogenes. DNA transposon Pot3 was identified in the coding regions of chromatin remodelling protein containing tyrosinase copper-binding and PWWP domains. LTR-retrotransposons Pyret and MAGGY are identified as key components responsible for the high genomic instability and perhaps these TEs are utilized by M. oryzae for its acclimatization to adverse environmental conditions. Our results demonstrate how common field stresses change genome dynamics of pathogen and provide perspective to explore the role of TEs in genome adaptability, signalling network and its impact on the virulence of fungal pathogens.
Seixas, Claudine D S; Barreto, Robert W; Killgore, Eloise
A survey of fungal pathogens of Miconia calvescens was carried out in Brazil aimed at finding potential classical biocontrol agents for management of this invasive alien weed in Hawaii. Coccodiella miconiae, Glomerella cingulata (= Colletotrichum gloeosporioides f. sp. miconiae) and the new species Guignardia miconiae and Korunomyces prostratus were found associated with foliar diseases and are described herein. Two previously undescribed spore stages of Coccodiella miconiae also were obtained allowing a complete description of this species. Pseudocercospora tamonae associated with leaf spots of other species of Miconia also was collected and also was proven to be pathogenic to M. calvescens.
Hussain, F.; Abid, M.; Farzana, A.; Shaukat, S.; Akbar, M.
The antifungal activity of different medicinal and locally available plants extracts (leaves, fruit, seeds) which are usually found in the surrounding of fields or in the fields on some fungi were tested in lab conditions. Six different plants were selected for testing these plants were Acacia nilotica (Lamk.) Willd. Azadirachta indica (A.) Juss. Crotalaria juncea L. Eucalyptus camaldulensis Dehnh. Ocimum basilicum L. and Prosopis juliflora (Sw.) Dc. These plants showed antifungal activity against the Aspergillus flavus, A. niger, Fusarium solani, Macrophomina phaseolina and Rhizoctonia solani. These plants crude extracts of leaves showed inhibition activity against the fungi and suppressed the myclial growth. Over all selected plants exhibited moderate type of inhibition against these above mentioned pathogens. Among these plants, Azadirachta indica, Ocimum basilicum and Crotalaria juncea showed the most effective results against the Aspergillus, Fusarium and Rhizoctonia sp. of fungal pathogens. Whereas, Acacia nilotica, Eucalyptus camaldulensis and Prosopis juliflora showed least potential of inhibition against all above mentioned fungal pathogens. It is investigated in present studies that Azadirachta indica, Ocimum basilicum and Crotalaria juncea can be utilized against the management of fungal diseases particularly Aspergillus flavus, A. niger, Fusarium solani, Macrophomina phaseolina and Rhizoctonia solani. (author)
Nowara, Daniela; Gay, Alexandra; Lacomme, Christophe; Shaw, Jane; Ridout, Christopher; Douchkov, Dimitar; Hensel, Götz; Kumlehn, Jochen; Schweizer, Patrick
Powdery mildew fungi are obligate biotrophic pathogens that only grow on living hosts and cause damage in thousands of plant species. Despite their agronomical importance, little direct functional evidence for genes of pathogenicity and virulence is currently available because mutagenesis and transformation protocols are lacking. Here, we show that the accumulation in barley (Hordeum vulgare) and wheat (Triticum aestivum) of double-stranded or antisense RNA targeting fungal transcripts affects the development of the powdery mildew fungus Blumeria graminis. Proof of concept for host-induced gene silencing was obtained by silencing the effector gene Avra10, which resulted in reduced fungal development in the absence, but not in the presence, of the matching resistance gene Mla10. The fungus could be rescued from the silencing of Avra10 by the transient expression of a synthetic gene that was resistant to RNA interference (RNAi) due to silent point mutations. The results suggest traffic of RNA molecules from host plants into B. graminis and may lead to an RNAi-based crop protection strategy against fungal pathogens.
Akita, Motomu; Lehtonen, Mikko T; Koponen, Hilkka; Marttinen, Eeva M; Valkonen, Jari P T
Drought and heat tolerance of the Sunagoke moss (Racomitrium japonicum) and the low thermal conductivity of the dry moss tissue offer novel greening and insulation possibilities of roofs and walls to mitigate the heat island phenomenon in urban environments. However, damage may appear in the moss panels under humid conditions in Japan. In this study we characterized fungi associated with the damaged areas of the Sunagoke moss panels. Fungi were identified by morphology and internal transcribed spacer (ITS) sequence analysis and tested for pathogenicity on R. japonicum (Grimmiaceae) and an unrelated moss species (Physcomitrella patens; Funariaceae) under controlled conditions. Alternaria alternata, Fusarium avenaceum and Fusarium oxysporum caused severe necrosis and death, whereas Cladosporium oxysporum and Epicoccum nigrum caused milder discoloration or chlorosis in both moss species. The fungi pathogenic on moss were closely related to fungal pathogens described from cultivated vascular plants. Ammonium increased severity of fungal diseases in moss. This study demonstrated that fungi can cause economically significant diseases in cultivated moss and hamper commercial use of the moss panels unless appropriate control methods are developed. Use of a single moss clone to cover large surfaces and the air pollutants such as ammonium may increase the risk for fungal disease problems. Copyright © 2011 Elsevier B.V. All rights reserved.
Koudela, M.; Novotný, Čeněk
Roč. 64, č. 4 (2016), s. 1181-1189 ISSN 1211-8516 R&D Projects: GA MZe QJ1210165 Institutional support: RVO:61388971 Keywords : carrot * onion * fungal pathogens * plants infection Subject RIV: EE - Microbiology, Virology
Manici, L M; Bregaglio, S; Fumagalli, D; Donatelli, M
Soil-borne fungal plant pathogens, agents of crown and root rot, are seldom considered in studies on climate change and agriculture due both to the complexity of the soil system and to the incomplete knowledge of their response to environmental drivers. A controlled chamber set of experiments was carried out to quantify the response of six soil-borne fungi to temperature, and a species-generic model to simulate their response was developed. The model was linked to a soil temperature model inclusive of components able to simulate soil water content also as resulting from crop water uptake. Pathogen relative growth was simulated over Europe using the IPCC A1B emission scenario derived from the Hadley-CM3 global climate model. Climate scenarios of soil temperature in 2020 and 2030 were compared to the baseline centred in the year 2000. The general trend of the response of soil-borne pathogens shows increasing growth in the coldest areas of Europe; however, a larger rate of increase is shown from 2020 to 2030 compared to that of 2000 to 2020. Projections of pathogens of winter cereals indicate a marked increase of growth rate in the soils of northern European and Baltic states. Fungal pathogens of spring sowing crops show unchanged conditions for their growth in soils of the Mediterranean countries, whereas an increase of suitable conditions was estimated for the areals of central Europe which represent the coldest limit areas where the host crops are currently grown. Differences across fungal species are shown, indicating that crop-specific analyses should be ran.
Two farmer's fields were visited per village where five diseased plants were collected per field. Three pathogens identified from the samples collected in the diseased fields: Sclerotium rolfsii, Fusarium oxysporum f. sp. lycopersici and F. solani. Pathogenicity test conducted for each of the isolated pathogens was positive.
Bancal, Marie-Odile; Hansart, Amandine; Sache, Ivan; Bancal, Pierre
Background and Aims Experiments have shown that biotrophic fungi divert assimilates for their growth. However, no attempt has been made either to account for this additional sink or to predict to what extent it competes with both grain filling and plant reserve metabolism for carbon. Fungal sink competitiveness with grains was quantified by a mixed experimental–modelling approach based on winter wheat infected by Puccinia triticina. Methods One week after anthesis, plants grown under controlled conditions were inoculated with varying loads. Sporulation was recorded while plants underwent varying degrees of shading, ensuring a range of both fungal sink and host source levels. Inoculation load significantly increased both sporulating area and rate. Shading significantly affected net assimilation, reserve mobilization and sporulating area, but not grain filling or sporulation rates. An existing carbon partitioning (source–sink) model for wheat during the grain filling period was then enhanced, in which two parameters characterize every sink: carriage capacity and substrate affinity. Fungal sink competitiveness with host sources and sinks was modelled by representing spore production as another sink in diseased wheat during grain filling. Key Results Data from the experiment were fitted to the model to provide the fungal sink parameters. Fungal carriage capacity was 0·56 ± 0·01 µg dry matter °Cd−1 per lesion, much less than grain filling capacity, even in highly infected plants; however, fungal sporulation had a competitive priority for assimilates over grain filling. Simulation with virtual crops accounted for the importance of the relative contribution of photosynthesis loss, anticipated reserve depletion and spore production when light level and disease severity vary. The grain filling rate was less reduced than photosynthesis; however, over the long term, yield loss could double because the earlier reserve depletion observed here would shorten the
Willsey, Telsa; Chatterton, Syama; Cárcamo, Héctor
Soilborne fungal and oomycete pathogens are the causal agents of several important plant diseases. Infection frequently co-occurs with herbivory by root-feeding insects, facilitating tripartite interactions that modify plant performance and mortality. In an agricultural context, interactions between pathogens, herbivores, and plants can have important consequences for yield protection. However, belowground interactions are inherently difficult to observe and are often overlooked. Here, we review the impact of direct and indirect interactions between root-associated insects, fungi, and oomycetes on the development of plant disease. We explore the relationship between insect feeding injury and pathogen infection, as well as the role of insects as vectors of fungal and oomycete pathogens. Synergistic interactions between insects and phytopathogens may be important in weed suppression, and we highlight several promising candidates for biocontrol. Bridging the gap between entomological and pathological research is a critical step in understanding how interactions between insects and microorganisms modify the community structure of the rhizosphere, and how this impacts plant functioning. Furthermore, the identification of belowground interactions is required to develop effective pest monitoring and management strategies. PMID:29104577
Full Text Available Soilborne fungal and oomycete pathogens are the causal agents of several important plant diseases. Infection frequently co-occurs with herbivory by root-feeding insects, facilitating tripartite interactions that modify plant performance and mortality. In an agricultural context, interactions between pathogens, herbivores, and plants can have important consequences for yield protection. However, belowground interactions are inherently difficult to observe and are often overlooked. Here, we review the impact of direct and indirect interactions between root-associated insects, fungi, and oomycetes on the development of plant disease. We explore the relationship between insect feeding injury and pathogen infection, as well as the role of insects as vectors of fungal and oomycete pathogens. Synergistic interactions between insects and phytopathogens may be important in weed suppression, and we highlight several promising candidates for biocontrol. Bridging the gap between entomological and pathological research is a critical step in understanding how interactions between insects and microorganisms modify the community structure of the rhizosphere, and how this impacts plant functioning. Furthermore, the identification of belowground interactions is required to develop effective pest monitoring and management strategies.
Rodriguez, R.J.; Redman, R.S.
This chapter discusses various biochemical, genetic, ecological, and evolutionary aspects of fungi that express either symbiotic or saprophytic life-styles. An enormous pool of potential pathogens exists in both agricultural and natural ecosystems, and virtually all plant species are susceptible to one or more fungal pathogens. Fungal pathogens have the potential to impact on the genetic structure of populations of individual plant species, the composition of plant communities and the process of plant succession. Endophytic fungi exist for at least part of their life cycles within the tissues of a plant host. This group of fungi is distinguished from plant pathogens because they do not elicit significant disease symptoms. However, endophytes do maintain the genetic and biochemical mechanisms required for infection and colonization of plant hosts. Fungi that obtain chemical nutrients from dead organic matter are known as saprophytes and are critical to the dynamics and resilience of ecosystems. There are two modes of saprophytic growth: one in which biomolecules that are amenable to transport across cell walls and membranes are directly absorbed, and another in which fungi must actively convert complex biopolymers into subunit forms amenable to transportation into cells. Regardless of life-style, fungi employ similar biochemical mechanisms for the acquisition and conversion of nutrients into complex biomolecules that are necessary for vegetative growth, production and dissemination of progeny, organismal competition, and survival during periods of nutrient deprivation or environmental inclemency.
Lievens, B.; Thomma, B.P.H.J.
The failure to adequately identify plant pathogens from culture-based morphological techniques has led to the development of culture-independent molecular approaches. Increasingly, diagnostic laboratories are pursuing fast routine methods that provide reliable identification, sensitive detection,
Maubon, Danièle; Dard, Céline; Garnaud, Cécile; Cornet, Muriel
Fungemia presents high morbi-mortality and thus rapid microbiological diagnosis may contribute to appropriate patient management. In the last decade, kits based on molecular technologies have become available and health care institutes are increasingly facing critical investment choices. Although all these tools aim to achieve rapid fungal detection and species identification, they display different inherent characteristics. Areas covered: Considering technologies allowing detection and identification of fungal species in a sepsis context, the market proposes either tests on positive blood culture or tests on patient's whole blood. In this review, the authors describe and compare the ePlex® Blood Culture Identification Fungal Pathogen (BCID-FP) test, a fully automated one-step single-use cartridge assay that has been designed to detect identify frequent or rare but emerging, fungal species, from positive blood culture. A comparison with the competing kits is provided. Expert commentaries: The ePlex BCID-FP test provides a diversified and rather relevant panel. Its easy-to-use cartridges allow flexible use around the clock. Nevertheless, prospective clinical studies assessing the time-to-result benefit on antifungal stewardship and on hospital length of stay are not available yet. New tools aim to benefit clinicians and patients, but they should be accompanied by supervision of result interpretation and adaptation of antifungal stewardship.
Rebecca A Hall
Full Text Available When colonising host-niches or non-animated medical devices, individual cells of the fungal pathogen Candida albicans expand into significant biomasses. Here we show that within such biomasses, fungal metabolically generated CO(2 acts as a communication molecule promoting the switch from yeast to filamentous growth essential for C. albicans pathology. We find that CO(2-mediated intra-colony signalling involves the adenylyl cyclase protein (Cyr1p, a multi-sensor recently found to coordinate fungal responses to serum and bacterial peptidoglycan. We further identify Lys 1373 as essential for CO(2/bicarbonate regulation of Cyr1p. Disruption of the CO(2/bicarbonate receptor-site interferes selectively with C. albicans filamentation within fungal biomasses. Comparisons between the Drosophila melanogaster infection model and the mouse model of disseminated candidiasis, suggest that metabolic CO(2 sensing may be important for initial colonisation and epithelial invasion. Our results reveal the existence of a gaseous Candida signalling pathway and its molecular mechanism and provide insights into an evolutionary conserved CO(2-signalling system.
Gabriel, K T; Joseph Sexton, D; Cornelison, C T
Volatile organic compounds (VOCs) are known to be produced by a wide range of micro-organisms and for a number of purposes. Volatile-based microbial inhibition in environments such as soil is well-founded, with numerous antimicrobial VOCs having been identified. Inhibitory VOCs are of interest as microbial control agents, as low concentrations of gaseous VOCs can elicit significant antimicrobial effects. Volatile organic compounds are organic chemicals typically characterized as having low molecular weight, low solubility in water, and high vapour pressure. Consequently, VOCs readily evaporate to the gaseous phase at standard temperature and pressure. This contact-independent antagonism presents unique advantages over traditional, contact-dependent microbial control methods, including increased surface exposure and reduced environmental persistence. This approach has been the focus of our recent research, with positive results suggesting it may be particularly promising for the management of emerging fungal pathogens, such as the causative agents of white-nose syndrome of bats and snake fungal disease, which are difficult or impossible to treat using traditional approaches. Here, we review the history of volatile-based microbial control, discuss recent progress in formulations that mimic naturally antagonistic VOCs, outline the development of a novel treatment device, and highlight areas where further work is needed to successfully deploy VOCs against existing and emerging fungal pathogens. © 2017 The Society for Applied Microbiology.
Chen, Sharon C-A; Meyer, Wieland; Pashley, Catherine H
Study of the clinical significance of fungal colonization/infection in the airways of cystic fibrosis (CF) patients, especially by filamentous fungi, is challenged by the absence of standardized methodology for the detection and identification of an ever-broadening range of fungal pathogens. Culture-based methods remain the cornerstone diagnostic approaches, but current methods used in many clinical laboratories are insensitive and unstandardized, rendering comparative studies unfeasible. Guidelines for standardized processing of respiratory specimens and for their culture are urgently needed and should include recommendations for specific processing procedures, inoculum density, culture media, incubation temperature and duration of culture. Molecular techniques to detect fungi directly from clinical specimens include panfungal PCR assays, multiplex or pathogen-directed assays, real-time PCR, isothermal methods and probe-based assays. In general, these are used to complement culture. Fungal identification by DNA sequencing methods is often required to identify cultured isolates, but matrix-assisted laser desorption/ionization time-of-flight mass spectrometry is increasingly used as an alternative to DNA sequencing. Genotyping of isolates is undertaken to investigate relatedness between isolates, to pinpoint the infection source and to study the population structure. Methods range from PCR fingerprinting and amplified fragment length polymorphism analysis, to short tandem repeat typing, multilocus sequencing typing (MLST) and whole genome sequencing (WGS). MLST is the current preferred method, whilst WGS offers best case resolution but currently is understudied.
Hast, Michael A; Nichols, Connie B; Armstrong, Stephanie M; Kelly, Shannon M; Hellinga, Homme W; Alspaugh, J Andrew; Beese, Lorena S
Cryptococcus neoformans is a fungal pathogen that causes life-threatening infections in immunocompromised individuals, including AIDS patients and transplant recipients. Few antifungals can treat C. neoformans infections, and drug resistance is increasing. Protein farnesyltransferase (FTase) catalyzes post-translational lipidation of key signal transduction proteins and is essential in C. neoformans. We present a multidisciplinary study validating C. neoformans FTase (CnFTase) as a drug target, showing that several anticancer FTase inhibitors with disparate scaffolds can inhibit C. neoformans and suggesting structure-based strategies for further optimization of these leads. Structural studies are an essential element for species-specific inhibitor development strategies by revealing similarities and differences between pathogen and host orthologs that can be exploited. We, therefore, present eight crystal structures of CnFTase that define the enzymatic reaction cycle, basis of ligand selection, and structurally divergent regions of the active site. Crystal structures of clinically important anticancer FTase inhibitors in complex with CnFTase reveal opportunities for optimization of selectivity for the fungal enzyme by modifying functional groups that interact with structurally diverse regions. A substrate-induced conformational change in CnFTase is observed as part of the reaction cycle, a feature that is mechanistically distinct from human FTase. Our combined structural and functional studies provide a framework for developing FTase inhibitors to treat invasive fungal infections.
Beaussart, Audrey; El-Kirat-Chatel, Sofiane; Fontaine, Thierry; Latgé, Jean-Paul; Dufrêne, Yves F.
Many fungal pathogens produce cell surface polysaccharides that play essential roles in host-pathogen interactions. In Aspergillus fumigatus, the newly discovered polysaccharide galactosaminogalactan (GAG) mediates adherence to a variety of substrates through molecular mechanisms that are poorly understood. Here we use atomic force microscopy to unravel the localization and adhesion of GAG on living fungal cells. Using single-molecule imaging with tips bearing anti-GAG antibodies, we found that GAG is massively exposed on wild-type (WT) germ tubes, consistent with the notion that this glycopolymer is secreted by the mycelium of A. fumigatus, while it is lacking on WT resting conidia and on germ tubes from a mutant (Δuge3) deficient in GAG. Imaging germ tubes with tips bearing anti-β-glucan antibodies shows that exposure of β-glucan is strongly increased in the Δuge3 mutant, indicating that this polysaccharide is masked by GAG during hyphal growth. Single-cell force measurements show that expression of GAG on germ tubes promotes specific adhesion to pneumocytes and non-specific adhesion to hydrophobic substrates. These results provide a molecular foundation for the multifunctional adhesion properties of GAG, thus suggesting it could be used as a potential target in anti-adhesion therapy and immunotherapy. Our methodology represents a powerful approach for characterizing the nanoscale organization and adhesion of cell wall polysaccharides during fungal morphogenesis, thereby contributing to increase our understanding of their role in biofilm formation and immune responses.
The use of antagonist microorganisms against fungal plant pathogens is an attractive and ecologically alternative to the use of chemical pesticides. Streptomyces are beneficial soil bacteria and potential candidates for biocontrol agents. This study reports the isolation, characterization and antagonist activity of soil streptomycetes from the Los Petenes Biosphere Reserve, a Natural protected area in Campeche, Mexico. The results showed morphological, physiological and biochemical characterization of six actinomycetes and their inhibitory activity against Curvularia sp., Aspergillus niger, Helminthosporium sp. and Fusarium sp. One isolate, identified as Streptomyces sp. CACIS-1.16CA showed the potential to inhibit additional pathogens as Alternaria sp., Phytophthora capsici, Colletotrichum sp. and Rhizoctonia sp. with percentages ranging from 47 to 90 %. This study identified a streptomycete strain with a broad antagonist activity that could be used for biocontrol of plant pathogenic fungi.
Thomas, S W; Rasmussen, S W; Glaring, M A; Rouster, J A; Christiansen, S K; Oliver, R P
Powdery mildew of barley is caused by the obligate fungal pathogen Blumeria graminis f. sp. hordei. Haploid conidia of B. graminis, landing on the barley leaf, germinate to form first a primary germ tube and then an appressorial germ tube. The appressorial germ tube differentiates into a mature appressorium from which direct penetration of host epidermis occurs. Here we present data on 4908 expressed sequence tags obtained from B. graminis conidia. The combined sequences represent 2676 clones describing 1669 individual genes. Comparison with sequences from other pathogenic and nonpathogenic fungi defines hypotheses on the genes required for pathogenicity and growth on the host. The putative roles of some of the identified genes are discussed. Copyright 2001 Academic Press.
Bosso, L.; Lacatena, F.; Varlese, R.; Nocerino, S.; Cristinzio, G.; Russo, D.
We assessed whether the presence and abundance of plant pathogens and antagonists change in soil fungal communities along a land abandonment gradient. The study was carried out in the Cilento area (Southern Italy) at a site with three different habitats found along a land abandonment gradient: agricultural land, Mediterranean shrubland and woodland. For all microbiological substrates the colony forming units were about 3.1 × 106 g-1 soil for agricultural land and about 1.1 × 106 g-1 soil for Mediterranean shrubland and woodland. We found the following genera in all habitats: Cladosporium, Mortierella, Penicillium and Trichoderma. In agricultural land, the significantly most abundant fungus genera were Aspergillus, Fusarium, Cylindrocarpon and Nectria; in Mediterranean shrubland, Rhizopus and Trichoderma; and in woodland, Bionectria, Mortierella, Cladosporium, Diplodia, Paecilomyces, Penicillium and Trichoderma. We found a total of 8, 8 and 9 species of fungal antagonist, and 16, 6 and 6 species of fungal plant pathogens in agricultural land, Mediterranean shrubland and woodland respectively. Fungal plant pathogens decreased significantly over a land abandonment gradient, while we no found significant differences among fungal antagonists in the three habitats. We conclude that a decrease in the number of fungal pathogen species occurs when formerly cultivated areas are abandoned. On the other hand, fungal antagonists seem not to be affected by this process.
Francisco J. Enguita
Full Text Available Fungal invasive infections are an increasing health problem. The intrinsic complexity of pathogenic fungi and the unmet clinical need for new and more effective treatments requires a detailed knowledge of the infection process. During infection, fungal pathogens are able to trigger a specific transcriptional program in their host cells. The detailed knowledge of this transcriptional program will allow for a better understanding of the infection process and consequently will help in the future design of more efficient therapeutic strategies. Simultaneous transcriptomic studies of pathogen and host by high-throughput sequencing (dual RNA-seq is an unbiased protocol to understand the intricate regulatory networks underlying the infectious process. This protocol is starting to be applied to the study of the interactions between fungal pathogens and their hosts. To date, our knowledge of the molecular basis of infection for fungal pathogens is still very limited, and the putative role of regulatory players such as non-coding RNAs or epigenetic factors remains elusive. The wider application of high-throughput transcriptomics in the near future will help to understand the fungal mechanisms for colonization and survival, as well as to characterize the molecular responses of the host cell against a fungal infection.
Malcolm, Glenna M; Kuldau, Gretchen A; Gugino, Beth K; Jiménez-Gasco, María Del Mar
Much of the current knowledge on population biology and ecology of soilborne fungal pathogens has been derived from research based on populations recovered from plants displaying disease symptoms or soil associated with symptomatic plants. Many soilborne fungal pathogens are known to cause disease on a large number of crop plants, including a variety of important agronomical, horticultural, ornamental, and forest plants species. For instance, the fungus Verticillium dahliae causes disease on >400 host plants. From a phytopathological perspective, plants on which disease symptoms have not been yet observed are considered to be nonhosts for V. dahliae. This term may be misleading because it does not provide information regarding the nature of the plant-fungus association; that is, a nonhost plant may harbor the fungus as an endophyte. Yet, there are numerous instances in the literature where V. dahliae has been isolated from asymptomatic plants; thus, these plants should be considered hosts. In this article, we synthesize scattered research that indicates that V. dahliae, aside from being a successful and significant vascular plant pathogen, may have a cryptic biology on numerous asymptomatic plants as an endophyte. Thus, we suggest here that these endophytic associations among V. dahliae and asymptomatic plants are not unusual relationships in nature. We propose to embrace the broader ecology of many fungi by differentiating between "symptomatic hosts" as those plants in which the infection and colonization by a fungus results in disease, and "asymptomatic hosts" as those plants that harbor the fungus endophytically and are different than true nonhosts that should be used for plant species that do not interact with the given fungus. In fact, if we broaden our definition of "host plant" to include asymptomatic plants that harbor the fungus as an endophyte, it is likely that the host ranges for some soilborne fungal pathogens are much larger than previously envisioned
Full Text Available Crown rot pathogens are associated with higher losses for wheat crop farmers, but information about the distribution and prevalence of these pathogens in Chile is inadequate. Distribution and prevalence of wheat (Triticum aestivum L. crown rot pathogens were examined in a survey of 48 commercial fields from December 2011 to February 2012 in southern Chile. These fields were located between Collipulli (37°56'00" S; 72°26'39" W and Purranque (40°50'30" S; 73°22'03" W. Severity of crown rot disease was determined through visual assessment of the first internode of 20 tillers obtained from each field. Incidence of crown rot pathogens per field was determined by plating the 20 tillers on Petri plates with 20% potato dextrose agar amended with lactic acid (aPDA medium. Resulting fungal colonies from monoxenic culture were identified by morphological or molecular-assisted identification. Severity of crown rot varied between 11.3% and 80% for individual fields. Culture plate analysis showed 72.2% of stems were infected with some fungus. Fusarium avenaceum, F. graminearum, and F. culmorum, pathogens associated with Fusarium crown rot disease were isolated from 13.5% of tillers. Gaeumannomyces graminis, causal agent of take-all disease in cereals, was isolated from 11.1% of culms. Phaeosphaeria sp., an endophyte and possibly a non-pathogenic fungus, was isolated from 13.9% of tillers. Pathogenic fungi such as Rhizoctonia spp. and Microdochium nivale, other saprophyte, and several unidentified non-sporulating fungi were isolated at frequencies lower than 3% of the total. Fusarium crown rot and take-all were the most prevalent and distributed crown rot diseases present in wheat crops in southern Chile.
Fungal endophytes of the obligate parasitic dwarf mistletoe Arceuthobium americanum (Santalaceae) act antagonistically in vitro against the native fungal pathogen Cladosporium (Davidiellaceae) of their host.
Martin, Lyssa L; Ross Friedman, Cynthia M; Phillips, Lori A
Endophytic fungi likely occur in all plants, yet little is known about those of parasitic plants, despite their potential to influence parasite success. Arceuthobium americanum is a parasitic angiosperm that greatly compromises the North American timber industry. We hypothesized that (1) A. americanum hosts fungal endophytes, and (2) these endophytes help A. americanum resist infection by fungal pathogens. • Healthy A. americanum stem and fruit tissues were differentially stained for cellulose and chitin and visualized using fluorescence microscopy. Stem sections (sterilized vs. unsterilized) and seeds were incubated on agar plates to cultivate fungi, both to extract DNA for ITS rDNA sequencing and to observe interactions with native fungi from unsterilized specimens. • Aside from xylem vessel elements, fungal structures were observed in all tissues, including those of the embryo. The ITS sequences of fungi cultured from internal tissues closely matched those of the known endophytes Phoma, Sydowia, and Phacidiopycnis, while those of surface organisms closely matched Cladosporium spp. Cultured fungi from internal tissues (putative endophytes) inhibited the growth of the surface organisms without affecting the other endophytes. • Fungal communities are established in A. americanum stems as well as in fruits and seeds, suggesting vertical transmission. These internally derived fungi act antagonistically toward fungi with pathogenic tendencies. As such, native mistletoe endophytes might protect A. americanum against fungal pathogens in nature. In the future, manipulation of endophytes might be a component of mistletoe control programs.
This paper reviews the drought impact on fungal pathogen of tomato. It presents the 11 Main Procedures used to conduct the experiments and discusses materials used. The 11 procedures are: Gather All the Soils, Sterilize the Soils Using Auto-Clave, Water Retention Test Using Auto-Clave, Cultivate Pathogen, Grow Tomato Plant, Count Pathogenic Cells, Inoculate the Pathogen, Conduct Root Dip, Grow Positive and Negative Samples, Test for Fusarium, and the Soil Separation Experiment with Pathogenic Soil. Experiments conducted on 6 Main Soils used in farming throughout California. The Yolo Series, Whiterock Series, Euic Soil, Potting Soil, Blacklock Series, and Henneke Series. The 6 Soils include amounts of clay, silt, sand, loam, and humus. It was crucial that these soils include these properties because deriving from last year's research I found that these particles in the soil has a role in the growth of the plant. Next, I tested the dry/wet weight of the soils, as this gave me a good estimate of how much water the soils can retain. This is very important because I found a direct correlation between the soil that retained the most amount of water and the soil that had the least harms done. Next, the other labs were completed to cultivate, inoculate, and test the pathogens in the soil, now these steps must be carried out with accuracy and precision because pathogens are a biological agent that causes disease or illness to its host, and if even 0.100 mL is changed in the pathogenic level it can make a large difference. Later, after I finished conducting the root dip, and raising the tomato plants. I counted the Fusarium count in the soil and plated the samples, where I was able to find the results on how much harm the pathogen had on the plant. In each of the 90 reps. the Fusarium (soilborne pathogen) decreased a little, which factors in the transfer from Potato Dextrose Agar Petri Dish to the Soils. After, this transfer the pathogen decreased and never increased, but
May Waine Wityi Htun; Myat Thu; Saw Sandar Maw
Seven species of Trichoderma were isolated from rhizospheric soil sources and studied by cultural morphology and microscopic examinations. In dual plate assay, antifungal effects of seven Trichoderma strains were screened against three plant pathogenic fungi (Fusarium oxysporum, Rhizoctonia solani and Pythium sp.) on PDA medium and T-5 isolate showed a wide percentage of inhibitory effects on target pathogens with PIRG value. All Trichoderma strains exhibited a clear zone formation on minimal synthetic medium supplemented with 1% colloidal chitin. T-2 and T-5 were the best chitinase producer strains. In vitro screening for protease activity, the highest protease producing activity of Trichoderma isolate (T-2) were observed in pH indicator medium after 7 days incubation. In pot trial experiment, only T-5 strain exhibited more fungal suppression efficiency on green gram plant than commercial fungicide, Trisan and the other strains. So, it can be said that the effective strain was T-5 strain only which have been more antifungal producing power on three fungal pathogens than Trisan and the resting strains.
Full Text Available Indigenous strains of Trichoderma species isolated from rhizosphere soils of Tea gardens of Assam, north eastern state of India were assessed for in vitro antagonism against two important tea fungal pathogens namely Pestalotia theae and Fusarium solani. A potent antagonist against both tea pathogenic fungi, designated as SDRLIN1, was selected and identified as Trichoderma viride. The strain also showed substantial antifungal activity against five standard phytopathogenic fungi. Culture filtrate collected from stationary growth phase of the antagonist demonstrated a significantly higher degree of inhibitory activity against all the test fungi, demonstrating the presence of an optimal blend of extracellular antifungal metabolites. Moreover, quantitative enzyme assay of exponential and stationary culture filtrates revealed that the activity of cellulase, β-1,3-glucanase, pectinase, and amylase was highest in the exponential phase, whereas the activity of proteases and chitinase was noted highest in the stationary phase. Morphological changes such as hyphal swelling and distortion were also observed in the fungal pathogen grown on potato dextrose agar containing stationary phase culture filtrate. Moreover, the antifungal activity of the filtrate was significantly reduced but not entirely after heat or proteinase K treatment, demonstrating substantial role of certain unknown thermostable antifungal compound(s in the inhibitory activity.
Touba, Eslaminejad Parizi; Zakaria, Maziah; Tahereh, Eslaminejad
Crude extracts of seven spices, viz. cardamom, chilli, coriander, onion, garlic, ginger, and galangale were made using cold water and hot water extraction and they were tested for their anti-fungal effects against the three Roselle pathogens i.e. Phoma exigua, Fusarium nygamai and Rhizoctonia solani using the 'poisoned food technique'. All seven spices studied showed significant anti-fungal activity at three concentrations (10, 20 and 30% of the crude extract) in-vitro. The cold water extract of garlic exhibited good anti-fungal activity against all three tested fungi. In the case of the hot water extracts, garlic and ginger showed the best anti-fungal activity. Of the two extraction methods, cold water extraction was generally more effective than hot water extraction in controlling the pathogens. Against P. exigua, the 10% cold water extracts of galangale, ginger, coriander and cardamom achieved total (100%) inhibition of pathogen mycelial growth. Total inhibition of F. nygamai mycelial growth was similarly achieved with the 10% cold water extracts garlic. Against R. solani, the 10% cold water extract of galangale was effective in imposing 100% inhibition. Accordingly, the 10% galangale extract effectively controlled both P. exigua and R. solani in vitro. None of the hot water extracts of the spices succeeded in achieving 100% inhibition of the pathogen mycelial growth. Copyright © 2011 Elsevier Ltd. All rights reserved.
Full Text Available Iron acquisition is a crucial virulence determinant for many bacteria and fungi, including the opportunistic fungal pathogens Candida albicans and C. glabrata. While the diverse strategies used by C. albicans for obtaining iron from the host are well-described, much less is known about the acquisition of this micronutrient from host sources by C. glabrata – a distant relative of C. albicans with closer evolutionary ties to Saccharomyces cerevisiae, which nonetheless causes severe clinical symptoms in humans. Here we show that C. glabrata is much more restricted than C. albicans in using host iron sources, lacking, for example, the ability to grow on transferrin and hemin/hemoglobin. Instead, C. glabrata is able to use ferritin and non-protein-bound iron (FeCl3 as iron sources in a pH-dependent manner. As in other fungal pathogens, iron-dependent growth requires the reductive high affinity (HA iron uptake system. Typically highly conserved, this uptake mechanism normally relies on initial ferric reduction by cell-surface ferric reductases. The C. glabrata genome contains only three such putative ferric reductases, which were found to be dispensable for iron-dependent growth. In addition and in contrast to C. albicans and S. cerevisiae, we also detected no surface ferric reductase activity in C. glabrata. Instead, extracellular ferric reduction was found in this and the two other fungal species, which was largely dependent on an excreted low-molecular weight, non-protein ferric reductant. We therefore propose an iron acquisition strategy of C. glabrata which differs from other pathogenic fungi, such as C. albicans, in that it depends on a limited set of host iron sources and that it lacks the need for surface ferric reductases. Extracellular ferric reduction by a secreted molecule possibly compensates for the loss of surface ferric reductase activity in the HA iron uptake system.
Eman M. Khalaf
Full Text Available The cucurbit vegetables, including cucumbers, melons and pumpkins, have been cultivated for thousands of years without fungicides. However, their seed germination stage is prone to be infected by soil-borne fungal and oomycete pathogens. Endophytes are symbionts that reside inside plant tissues including seeds. Seed endophytes are founders of the juvenile plant microbiome and can promote host defense at seed germination and later stages. We previously isolated 169 bacterial endophytes associated with seeds of diverse cultivated cucurbits. We hypothesized that these endophytes can antagonize major fungal and oomycete pathogens. Here we tested the endophytes for in vitro antagonism (dual culture assays against important soil-borne pathogens (Rhizoctonia solani, Fusarium graminearum, Phytophthora capsici, Pythium aphanideratum. The endophytes were also assayed in planta (leaf disk and detached leaf bioassays for antagonism against a foliar pathogen of global importance, Podosphaera fuliginea, the causative agent of cucurbit powdery mildew. The endophytes were further tested in vitro for secretion of volatile organic compounds (VOCs known to induce plant defense. Extracellular ribonuclease activity was also tested, as a subset of pathogenesis-related (PR proteins of plant hosts implicated in suppression of fungal pathogens, displays ribonuclease activity. An unexpected majority of the endophytes (70%, 118/169 exhibited antagonism to the five phytopathogens, of which 68% (50/73 of in vitro antagonists belong to the genera Bacillus and Paenibacillus. All Lactococcus and Pantoea endophytes exhibited anti-oomycete activity. However, amongst the most effective inoculants against Podosphaera fuliginea were Pediococcus and Pantoea endophytes. Interestingly, 67% (113/169 of endophytes emitted host defense inducing VOCs (acetoin/diacetyl and 62% (104/169 secreted extracellular ribonucleases in vitro, respectively. These results show that seeds of cultivated
Full Text Available We investigated the diversity and distribution of fungi in nine different sites inside 30 residential dishwashers. In total, 503 fungal strains were isolated, which belong to 10 genera and 84 species. Irrespective of the sampled site, 83% of the dishwashers were positive for fungi. The most frequent opportunistic pathogenic species were Exophiala dermatitidis, Candida parapsilosis sensu stricto, Exophiala phaeomuriformis, Fusarium dimerum, and the Saprochaete/Magnusiomyces clade. The black yeast E. dermatitidis was detected in 47% of the dishwashers, primarily at the dishwasher rubber seals, at up to 106 CFU/cm2; the other fungi detected were in the range of 102 to 105 CFU/cm2. The other most heavily contaminated dishwasher sites were side nozzles, doors and drains. Only F. dimerum was isolated from washed dishes, while dishwasher waste water contained E. dermatitidis, Exophiala oligosperma and Sarocladium killiense. Plumbing systems supplying water to household appliances represent the most probable route for contamination of dishwashers, as the fungi that represented the core dishwasher mycobiota were also detected in the tap water. Hot aerosols from dishwashers contained the human opportunistic yeast C. parapsilosis, Rhodotorula mucilaginosa and E. dermatitidis (as well as common air-borne genera such as Aspergillus, Penicillium, Trichoderma and Cladosporium. Comparison of fungal contamination of kitchens without and with dishwashers revealed that virtually all were contaminated with fungi. In both cases, the most contaminated sites were the kitchen drain and the dish drying rack. The most important difference was higher prevalence of black yeasts (E. dermatitidis in particular in kitchens with dishwashers. In kitchens without dishwashers, C. parapsilosis strongly prevailed with negligible occurrence of E. dermatitidis. F. dimerum was isolated only from kitchens with dishwashers, while Saprochaete/Magnusiomyces isolates were only found within
Full Text Available Chronic lung infections with opportunistic bacterial and fungal pathogens are a major cause of morbidity and mortality especially in patients with cystic fibrosis. Pseudomonas aeruginosa is the most frequently colonizing bacterium in these patients, and it is often found in association with the filamentous fungus Aspergillus fumigatus. P. aeruginosa is known to inhibit the growth of A. fumigatus in situations of direct contact, suggesting the existence of interspecies communication that may influence disease outcome. Our study shows that the lung pathogens P. aeruginosa and A. fumigatus can interact at a distance via volatile-mediated communication and expands our understanding of interspecific signaling in microbial communities.
Ordonez, Soledad R; Veldhuizen, Edwin J A; van Eijk, Martin; Haagsman, Henk P
Fungal infections of the lung are life-threatening but rarely occur in healthy, immunocompetent individuals, indicating efficient clearance by pulmonary defense mechanisms. Upon inhalation, fungi will first encounter the airway surface liquid which contains several soluble effector molecules that form the first barrier of defense against fungal infections. These include host defense peptides, like LL-37 and defensins that can neutralize fungi by direct killing of the pathogen, and collectins, such as surfactant protein A and D, that can aggregate fungi and stimulate phagocytosis. In addition, these molecules have immunomodulatory activities which can aid in fungal clearance from the lung. However, existing observations are based on in vitro studies which do not reflect the complexity of the lung and its airway surface liquid. Ionic strength, pH, and the presence of mucus can have strong detrimental effects on antifungal activity, while the potential synergistic interplay between soluble effector molecules is largely unknown. In this review, we describe the current knowledge on soluble effector molecules that contribute to antifungal activity, the importance of environmental factors and discuss the future directions required to understand the innate antifungal defense in the lung.
Claudio L. Donnici
Full Text Available The in vitro antifungal activity of nine dirutheniumpentadithiocarbamate complexes C1–C9 was investigated and assessed for its activity against four different fungal species with clinical interest and related to invasive fungal infections (IFIs, such as Candida spp. [C. albicans (two clinical isolates, C. glabrata, C. krusei, C. parapsolisis, C. tropicalis, C.dubliniensis (six clinical isolates], Paracoccidioides brasiliensis (seven clinical isolates, Cryptococcus neoformans and Sporothrix schenckii. All synthesized complexes C1–C9 and also the free ligands L1–L9 were submitted to in vitro tests against those fungi and the results are very promising, since some of the obtained MIC (minimal inhibitory concentration values were very low (from 10−6 mol mL−1 to 10−8 mol mL−1 against all investigated clinically relevant fungal pathogens, except for C. glabrata, that the MIC values are close to the ones obtained for fluconazole, the standard antifungal agent tested. Preliminary structure-activity relations (SAR might be suggested and a strong influence from steric and lipophilic parameters in the antifungal activity can be noticed. Cytotoxicity assays (IC50 showed that the complexes are not as toxic (IC50 values are much higher—30 to 200 fold—than MIC values. These ruthenium complexes are very promising lead compounds for novel antifungal drug development, especially in IFIs, one of most harmful emerging infection diseases (EIDs.
Full Text Available Eastern white pine is a crucial ecological and economic component of forests in the northern USA and eastern Canada, and is now facing an emerging problem in white pine needle damage (WPND. It is still unclear whether WPND results from one, or the combination of several fungal pathogens. Therefore, the first objective of this study was to characterize the fungi associated with WPND in the northeastern United States and document the damage being done to mature eastern white pine as a result of repeated defoliation. To date, 22 species of fungi, either cultured from diseased pine needles or formed fruiting bodies on pine needles were identified based on morphology and sequence data. Lecanosticta acicola and a putative new species of Septorioides were the species most frequently recovered from diseased needles, in addition to needle cast fungi Lophophacidium dooksii and Bifusella linearis, two obligate fungal pathogens that were frequently observed on pine needles in the northeast, but have not been known to cause excessive defoliation of eastern white pine. A second objective was to monitor yearly the health of 63 pairs of healthy and unhealthy trees in eight affected locations throughout New England. Since 2012, affected trees are increasingly and repeatedly chlorotic and defoliated every year. Trees that were initially healthy are now exhibiting symptoms. While L. acicola appears to be the primary pathogen causing WPND, several other common needle pathogens are being more frequently observed and the role of climate change may be important in the disease ecology of WPND. These defoliation events, while once a sporadic occurrence, have now become more frequent as observed in continued crown deterioration of eastern white pine in long-term monitoring plots followed during the course of this three-year study.
Full Text Available In mutualisms, each interacting species obtains resources from its partner that it would obtain less efficiently if alone, and so derives a net fitness benefit. In exchange for shelter (domatia and food, mutualistic plant-ants protect their host myrmecophytes from herbivores, encroaching vines and fungal pathogens. Although selective filters enable myrmecophytes to host those ant species most favorable to their fitness, some insects can by-pass these filters, exploiting the rewards supplied whilst providing nothing in return. This is the case in French Guiana for Cecropia obtusa (Cecropiaceae as Pseudocabima guianalis caterpillars (Lepidoptera, Pyralidae can colonize saplings before the installation of their mutualistic Azteca ants. The caterpillars shelter in the domatia and feed on food bodies (FBs whose production increases as a result. They delay colonization by ants by weaving a silk shield above the youngest trichilium, where the FBs are produced, blocking access to them. This probable temporal priority effect also allows female moths to lay new eggs on trees that already shelter caterpillars, and so to occupy the niche longer and exploit Cecropia resources before colonization by ants. However, once incipient ant colonies are able to develop, they prevent further colonization by the caterpillars. Although no higher herbivory rates were noted, these caterpillars are ineffective in protecting their host trees from a pathogenic fungus, Fusarium moniliforme (Deuteromycetes, that develops on the trichilium in the absence of mutualistic ants. Therefore, the Cecropia treelets can be parasitized by two often overlooked species: the caterpillars that shelter in the domatia and feed on FBs, delaying colonization by mutualistic ants, and the fungal pathogen that develops on old trichilia. The cost of greater FB production plus the presence of the pathogenic fungus likely affect tree growth.
Palmero, D; Rodríguez, J M; de Cara, M; Camacho, F; Iglesias, C; Tello, J C
In order to determine the presence of Fusarium spp. in atmospheric dust and rainfall dust, samples were collected during September 2007, and July, August, and October 2008. The results reveal the prevalence of airborne Fusarium species coming from the atmosphere of the South East coast of Spain. Five different Fusarium species were isolated from the settling dust: Fusarium oxysporum, F. solani, F. equiseti, F. dimerum, and F. proliferatum. Moreover, rainwater samples were obtained during significant rainfall events in January and February 2009. Using the dilution-plate method, 12 fungal genera were identified from these rainwater samples. Specific analyses of the rainwater revealed the presence of three species of Fusarium: F. oxysporum, F. proliferatum and F. equiseti. A total of 57 isolates of Fusarium spp. obtained from both rainwater and atmospheric rainfall dust sampling were inoculated onto melon (Cucumis melo L.) cv. Piñonet and tomato (Lycopersicon esculentum Mill.) cv. San Pedro. These species were chosen because they are the main herbaceous crops in Almeria province. The results presented in this work indicate strongly that spores or propagules of Fusarium are able to cross the continental barrier carried by winds from the Sahara (Africa) to crop or coastal lands in Europe. Results show differences in the pathogenicity of the isolates tested. Both hosts showed root rot when inoculated with different species of Fusarium, although fresh weight measurements did not bring any information about the pathogenicity. The findings presented above are strong indications that long-distance transmission of Fusarium propagules may occur. Diseases caused by species of Fusarium are common in these areas. They were in the past, and are still today, a problem for greenhouses crops in Almería, and many species have been listed as pathogens on agricultural crops in this region. Saharan air masses dominate the Mediterranean regions. The evidence of long distance dispersal
Rivero, Mercedes; Furman, Nicolás; Mencacci, Nicolás; Picca, Pablo; Toum, Laila; Lentz, Ezequiel; Bravo-Almonacid, Fernando; Mentaberry, Alejandro
Solanum tuberosum plants were transformed with three genetic constructions expressing the Nicotiana tabacum AP24 osmotine, Phyllomedusa sauvagii dermaseptin and Gallus gallus lysozyme, and with a double-transgene construction expressing the AP24 and lysozyme sequences. Re-transformation of dermaseptin-transformed plants with the AP24/lysozyme construction allowed selection of plants simultaneously expressing the three transgenes. Potato lines expressing individual transgenes or double- and triple-transgene combinations were assayed for resistance to Erwinia carotovora using whole-plant and tuber infection assays. Resistance levels for both infection tests compared consistently for most potato lines and allowed selection of highly resistant phenotypes. Higher resistance levels were found in lines carrying the dermaseptin and lysozyme sequences, indicating that theses proteins are the major contributors to antibacterial activity. Similar results were obtained in tuber infection tests conducted with Streptomyces scabies. Plant lines showing the higher resistance to bacterial infections were challenged with Phytophthora infestans, Rhizoctonia solani and Fusarium solani. Considerable levels of resistance to each of these pathogens were evidenced employing semi-quantitative tests based in detached-leaf inoculation, fungal growth inhibition and in vitro plant inoculation. On the basis of these results, we propose that stacking of these transgenes is a promising approach to achieve resistance to both bacterial and fungal pathogens. Copyright © 2011 Elsevier B.V. All rights reserved.
Ferreira, Ricardo B; Monteiro, Sara S; Piçarra-Pereira, M Antonieta; Teixeira, Artur R
The vast majority of wine proteins have recently been identified as pathogenesis-related (PR) proteins. During the growing season, these proteins are expressed in developmentally dependent and inducible manners in grapevine leaves and grape berries, in which they are believed to play an important role in protection against fungal pathogens and possibly other stresses. Because of their inherent resistance to proteolytic attack and to the low pH values characteristic of wines, vinification can be seen as a "purification strategy" for grape PR proteins. The inevitable consequent accumulation of these proteins in wines becomes a technological nuisance because they adversely affect the clarity and stability of wines. Genetically modified vines underexpressing PR proteins would certainly lead to stable wines but would increase the plant susceptibility to fungal attack, and the actual trend seems to be in the opposite direction, that is overexpressing these proteins to obtain plants with enhanced resistance to pathogens--a trend that will probably augment problems associated with protein instability in the resulting wines.
Cornman, R Scott; Bennett, Anna K; Murray, K Daniel; Evans, Jay D; Elsik, Christine G; Aronstein, Kate
We present a comprehensive transcriptome analysis of the fungus Ascosphaera apis, an economically important pathogen of the Western honey bee (Apis mellifera) that causes chalkbrood disease. Our goals were to further annotate the A. apis reference genome and to identify genes that are candidates for being differentially expressed during host infection versus axenic culture. We compared A. apis transcriptome sequence from mycelia grown on liquid or solid media with that dissected from host-infected tissue. 454 pyrosequencing provided 252 Mb of filtered sequence reads from both culture types that were assembled into 10,087 contigs. Transcript contigs, protein sequences from multiple fungal species, and ab initio gene predictions were included as evidence sources in the Maker gene prediction pipeline, resulting in 6,992 consensus gene models. A phylogeny based on 12 of these protein-coding loci further supported the taxonomic placement of Ascosphaera as sister to the core Onygenales. Several common protein domains were less abundant in A. apis compared with related ascomycete genomes, particularly cytochrome p450 and protein kinase domains. A novel gene family was identified that has expanded in some ascomycete lineages, but not others. We manually annotated genes with homologs in other fungal genomes that have known relevance to fungal virulence and life history. Functional categories of interest included genes involved in mating-type specification, intracellular signal transduction, and stress response. Computational and manual annotations have been made publicly available on the Bee Pests and Pathogens website. This comprehensive transcriptome analysis substantially enhances our understanding of the A. apis genome and its expression during infection of honey bee larvae. It also provides resources for future molecular studies of chalkbrood disease and ultimately improved disease management.
Full Text Available Abstract Background We present a comprehensive transcriptome analysis of the fungus Ascosphaera apis, an economically important pathogen of the Western honey bee (Apis mellifera that causes chalkbrood disease. Our goals were to further annotate the A. apis reference genome and to identify genes that are candidates for being differentially expressed during host infection versus axenic culture. Results We compared A. apis transcriptome sequence from mycelia grown on liquid or solid media with that dissected from host-infected tissue. 454 pyrosequencing provided 252 Mb of filtered sequence reads from both culture types that were assembled into 10,087 contigs. Transcript contigs, protein sequences from multiple fungal species, and ab initio gene predictions were included as evidence sources in the Maker gene prediction pipeline, resulting in 6,992 consensus gene models. A phylogeny based on 12 of these protein-coding loci further supported the taxonomic placement of Ascosphaera as sister to the core Onygenales. Several common protein domains were less abundant in A. apis compared with related ascomycete genomes, particularly cytochrome p450 and protein kinase domains. A novel gene family was identified that has expanded in some ascomycete lineages, but not others. We manually annotated genes with homologs in other fungal genomes that have known relevance to fungal virulence and life history. Functional categories of interest included genes involved in mating-type specification, intracellular signal transduction, and stress response. Computational and manual annotations have been made publicly available on the Bee Pests and Pathogens website. Conclusions This comprehensive transcriptome analysis substantially enhances our understanding of the A. apis genome and its expression during infection of honey bee larvae. It also provides resources for future molecular studies of chalkbrood disease and ultimately improved disease management.
Vaux, Sophie; Criscuolo, Alexis; Desnos-Ollivier, Marie; Diancourt, Laure; Tarnaud, Chloé; Vandenbogaert, Matthias; Brisse, Sylvain; Coignard, Bruno; Garcia-Hermoso, Dea; Blanc, Catherine; Hoinard, Damien; Lortholary, Olivier; Bretagne, Stéphane; Thiolet, Jean-Michel; de Valk, Henriette; Courbil, Rémi; Chabanel, Anne; Simonet, Marion; Maire, Francoise; Jbilou, Saadia; Tiberghien, Pierre; Blanchard, Hervé; Venier, Anne-Gaëlle; Bernet, Claude; Simon, Loïc; Sénéchal, Hélène; Pouchol, Elodie; Angot, Christiane; Ribaud, Patricia; Socié, G.; Flèche, M.; Brieu, Nathalie; Lagier, Evelyne; Chartier, Vanessa; Allegre, Thierry; Maulin, Laurence; Lanic, Hélène; Tilly, Hervé; Bouchara, Jean-Philippe; Pihet, Marc; Schmidt, Aline; Kouatchet, Achille; Vandamme, Yves-Marie; Ifrah, Norbert; Mercat, Alain; Accoceberry, Isabelle; Albert, Olivier; Leguay, Thibaut; Rogues, Anne-Marie; Bonhomme, Julie; Reman, Oumédaly; Lesteven, Claire; Poirier, Philippe; Chabrot, Cécile Molucon; Calvet, Laure; Baud, Olivier; Cambon, Monique; Farkas, Jean Chistophe; Lafon, Bruno; Dalle, Frédéric; Caillot, Denis; Lazzarotti, Aline; Aho, Serge; Combret, Sandrine; Facon, Thierry; Sendid, Boualem; Loridant, Séverine; Louis, Terriou; Cazin, Bruno; Grandbastien, Bruno; Bourgeois, Nathalie; Lotthé, Anne; Cartron, Guillaume; Ravel, Christophe; Colson, Pascal; Gaudard, Philippe; Bonmati, Caroline; Simon, Loic; Rabaud, Christian; Machouart, Marie; Poisson, Didier; Carp, Diana; Meunier, Jérôme; Gaschet, Anne; Miquel, Chantal; Sanhes, Laurence; Ferreyra, Milagros; Leibinger, Franck; Geudet, Philippe; Toubas, Dominique; Himberlin, Chantal; Bureau-Chalot, Florence; Delmer, Alain; Favennec, Loïc; Gargala, Gilles; Michot, Jean-Baptiste; Girault, Christophe; David, Marion; Leprêtre, Stéphane; Jardin, Fabrice; Honderlick, Pierre; Caille, Vincent; Cerf, Charles; Cassaing, Sophie; Recher, Christian; Picard, Muriel; Protin, Caroline; Huguet, Françoise; Huynh, Anne; Ruiz, Jean; Riu-Poulenc, Béatrice; Letocart, Philippe; Marchou, Bruno; Verdeil, Xavier; Cavalié, Laurent; Chauvin, Pamela; Iriart, Xavier; Valentin, Alexis; Bouvet, Emmanuelle; Delmas-Marsalet, Béatrice; Jeblaoui, Asma; Kassis-Chikhani, Najiby; Mühlethaler, Konrad; Zimmerli, Stefan; Zalar, Polona; Sánchez-Reus, Ferran; Gurgui, Merce
ABSTRACT Rapidly fatal cases of invasive fungal infections due to a fungus later identified as Saprochaete clavata were reported in France in May 2012. The objectives of this study were to determine the clonal relatedness of the isolates and to investigate possible sources of contamination. A nationwide alert was launched to collect cases. Molecular identification methods, whole-genome sequencing (WGS), and clone-specific genotyping were used to analyze recent and historical isolates, and a case-case study was performed. Isolates from thirty cases (26 fungemias, 22 associated deaths at day 30) were collected between September 2011 and October 2012. Eighteen cases occurred within 8 weeks (outbreak) in 10 health care facilities, suggesting a common source of contamination, with potential secondary cases. Phylogenetic analysis identified one clade (clade A), which accounted for 16/18 outbreak cases. Results of microbiological investigations of environmental, drug, or food sources were negative. Analysis of exposures pointed to a medical device used for storage and infusion of blood products, but no fungal contamination was detected in the unused devices. Molecular identification of isolates from previous studies demonstrated that S. clavata can be found in dairy products and has already been involved in monocentric outbreaks in hematology wards. The possibility that S. clavata may transmit through contaminated medical devices or can be associated with dairy products as seen in previous European outbreaks is highly relevant for the management of future outbreaks due to this newly recognized pathogen. This report also underlines further the potential of WGS for investigation of outbreaks due to uncommon fungal pathogens. PMID:25516620
Rahikainen Ibañez, T; Laukkanen-Ninios, R; Hakkinen, M; Johansson, T; Vilar, M; Korkeala, H
The prevalence of human pathogenic Yersinia enterocolitica was determined in tonsil and intestinal content samples from 388 healthy fattening pigs at the four biggest Finnish slaughterhouses. These slaughterhouses process 73% of pigs in Finland. Tonsil samples were tested by PCR targeted for yadA, and intestinal samples were cultured. All pathogenic Y. enterocolitica isolates represented bioserotype 4/O:3. The prevalence of Y. enterocolitica in tonsil samples was 60% (95% confidence limit, 55.4 to 65.1%), and its prevalence in intestinal samples was 26% (95% confidence limit, 22.1 to 31.2%). The prevalence of Y. enterocolitica in tonsil and intestinal samples varied between the four slaughterhouses. The tonsil prevalence of Y. enterocolitica was higher in slaughterhouse B, and the prevalence in intestinal content was higher in slaughterhouse C. There were more positive results in both tonsil and intestinal samples in pigs coming from fattening farms than in pigs coming from farrowing-and-fattening farms. A seasonal variation was observed in the prevalence of Y. enterocolitica in intestinal samples, with the highest prevalence during July and August, but no seasonal variation was detected in tonsil samples.
Graeme James Kettles
Full Text Available The Dothideomycete fungus Zymoseptoria tritici (previously known as Mycosphaerella graminicola and Septoria tritici is the causative agent of Septoria tritici leaf blotch (STB disease of wheat (Triticum aestivum L.. In Europe, STB is the most economically damaging disease of wheat, with an estimated ~€1 billion per year in fungicide expenditure directed towards its control. Here, an overview of our current understanding of the molecular events that occur during Z. tritici infection of wheat leaves is presented. On the host side, this includes the contribution of (1 the pathogen-associated molecular pattern-triggered immunity (PTI layer of the plant defence, and (2 major Stb resistance loci to Z. tritici resistance. On the pathogen side of the interaction, we consolidate evidence from recent bioinformatic, transcriptomic and proteomic studies that begin to explain the contribution of Z. tritici effector proteins to the biphasic lifestyle of the fungus. This includes the discovery of chitin-binding proteins in the Z. tritici secretome, which contribute to evasion of immune surveillance by this pathogen, and the possible existence of ‘necrotrophic’ effectors from Z. tritici, which may actively stimulate host recognition in a manner similar to related necrotrophic fungal pathogens. We finish by speculating on how some of these recent fundamental discoveries might be harnessed to help improve resistance to STB in the world’s second largest food crop.
Periodontitis is an infectious/inflammatory disease characterized by the loss of periodontal ligament and alveolar bone. Herpesviruses are frequent inhabitants of periodontitis lesions, and the periodontopathogenicity of these viruses is the topic of this review. In 26 recent studies from 15 countries, subgingival cytomegalovirus, Epstein-Barr virus and herpes simplex virus type 1, respectively, yielded median prevalences of 49%, 45% and 63% in aggressive periodontitis, 40%, 32% and 45% in chronic periodontitis, and 3%, 7% and 12% in healthy periodontium. An active herpesvirus infection of the periodontium exhibits site specificity, is a potent stimulant of cellular immunity, may cause upgrowth of periodontopathic bacteria and tends to be related to disease-active periodontitis. Pro-inflammatory cytokines induced by the herpesvirus infection may activate matrix metalloproteinases and osteoclasts, leading to breakdown of the tooth-supportive tissues. The notion that a co-infection of herpesviruses and specific bacteria causes periodontitis provides a plausible etiopathogenic explanation for the disease. Moreover, herpesvirus virions from periodontal sites may dislodge into saliva or enter the systemic circulation and cause diseases beyond the periodontium. Periodontal treatment can diminish significantly the periodontal load of herpesviruses, which may lower the incidence and magnitude of herpesvirus dissemination within and between individuals, and subsequently the risk of acquiring a variety of medical diseases. Novel and more effective approaches to the prevention and treatment of periodontitis and related diseases may depend on a better understanding of the herpesvirus-bacteria-immune response axis. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
The present study was conducted to find out the prevalence and spectrum of Gram negative pathogens causing bacterial meningitis and their antimicrobial susceptibility pattern in a tertiary care hospital. The cerebrospinal fluid (CSF) (3-5 ml) was collected from 638 admitted children clinically suspected of septic meningitis.
This study was carried out to determine the prevalence of mastitis pathogens at the Magadu Dairy Farm, Sokoine University of Agriculture. A total of 19 milk samples were collected and cultured on blood agar and MacConkey agar followed by identification of bacteria colonies and cells using standard laboratory techniques.
Laukkanen-Ninios, Riikka; Fredriksson-Ahomaa, Maria; Maijala, Riitta; Korkeala, Hannu
Samples from pork cuts for minced meat and cheeks from processing plants and a slaughterhouse, and modified atmosphere (MA) packaged pork from retail were studied to estimate the prevalence of pathogenic, i.e. virulence plasmid bearing, Yersinia enterocolitica and Yersinia pseudotuberculosis in pork, as well as to quantify pathogenic Y. enterocolitica in pork cuts. Pathogenic (virF-positive) Y. enterocolitica was isolated from 17 pig cheeks (23%) but not from any of the MA-packaged 54 retail pork samples and only from one of the 155 pork cut (0.6%). Most (16/17) of the cheek samples were contaminated with pathogenic Y. enterocolitica 4/O:3 and one with bioserotype 2/O:9. No Y. pseudotuberculosis was isolated. The prevalence of pathogenic Y. enterocolitica was clearly higher (39%) in 155 pork cuts when studied with nested PCR targeting yadA on the virulence plasmid pYV although the contamination level was low varying between 0.1 and 1.6 MPN/g. Raw pork cuts and especially pig cheeks may serve as possible sources for yersiniosis caused by pathogenic Y. enterocolitica. Copyright © 2014 Elsevier Ltd. All rights reserved.
Franco, Sulamita de Freitas; Baroni, Renata Moro; Carazzolle, Marcelo Falsarella; Teixeira, Paulo José Pereira Lima; Reis, Osvaldo; Pereira, Gonçalo Amarante Guimarães; Mondego, Jorge Maurício Costa
Thaumatin-like proteins (TLPs) are found in diverse eukaryotes. Plant TLPs, known as Pathogenicity Related Protein (PR-5), are considered fungal inhibitors. However, genes encoding TLPs are frequently found in fungal genomes. In this work, we have identified that Moniliophthora perniciosa, a basidiomycete pathogen that causes the Witches' Broom Disease (WBD) of cacao, presents thirteen putative TLPs from which four are expressed during WBD progression. One of them is similar to small TLPs, which are present in phytopathogenic basidiomycete, such as wheat stem rust fungus Puccinia graminis. Fungi genomes annotation and phylogenetic data revealed a larger number of TLPs in basidiomycetes when comparing with ascomycetes, suggesting that these proteins could be involved in specific traits of mushroom-forming species. Based on the present data, we discuss the contribution of TLPs in the combat against fungal competitors and hypothesize a role of these proteins in M. perniciosa pathogenicity. Copyright © 2015 Elsevier Inc. All rights reserved.
Rylev, Mette; Kilian, Mogens
putative periodontal pathogens and particular subsets of these species vary between ethnic groups. Few of these differences can, with the limited information available, be directly related to differences in periodontal disease prevalence. Asian populations are regularly colonized with Actinobacillus...... actinomycetemcomitans serotype c with questionable pathogenic potential. Conversely, the JP2 clone of A. actinomycetemcomitans has enhanced virulence and causes significantly higher prevalence of aggressive periodontitis in adolescents whose descent can be traced back to the Mediterranean and Western parts of Africa....... Some genetically distinct types of Porphyromonas gingivalis are more associated with disease than others, but additional work is required to relate this to clinical differences. CONCLUSIONS: Studies that take into account differences linked to the genetics of both patients and potential pathogens...
Jennifer A. Rudgers; Rebecca A. Fletcher; Eric Olivas; Carolyn A. Young; Nikki D. Charlton; Dean E. Pearson; John L. Maron
When symbionts are inherited by offspring, they can have substantial ecological and evolutionary consequences because they occur in all host life stages. Although natural frequencies of inherited symbionts are commonly <100 %, few studies investigate the ecological drivers of variation in symbiont prevalence. In plants, inherited fungal endophytes can...
Full Text Available Brassica juncea (Indian mustard is a commercially important oil seed crop, which is highly affected by many biotic stresses. Among them, Alternaria leaf blight and powdery mildew are the most devastating diseases leading to huge yield losses in B. juncea around the world. In this regard, genetic engineering is a promising tool that may possibly allow us to enhance the B. juncea disease resistance against these pathogens. NPR1 (non-expressor of pathogen-related gene 1 is a bonafide receptor of salicylic acid (SA which modulates multiple immune responses in plants especially activation of induced and systemic acquired resistance (SAR. Here, we report the isolation and characterization of new NPR1 homolog (BjNPR1 from B. juncea. The phylogenetic tree constructed based on the deduced sequence of BjNPR1 with homologs from other species revealed that BjNPR1 grouped together with other known NPR1 proteins of Cruciferae family, and was nearest to B. napus. Furthermore, expression analysis showed that BjNPR1 was upregulated after SA treatment and fungal infection but not by jasmonic acid or abscisic acid. To understand the defensive role of this gene, we generated B. juncea transgenic lines overexpressing BjNPR1, and further confirmed by PCR and Southern blotting. The transgenic lines showed no phenotypic abnormalities, and constitutive expression of BjNPR1 activates defense signaling pathways by priming the expression of antifungal PR genes. Moreover, BjNPR1 transgenic lines showed enhanced resistance to Alternaria brassicae and Erysiphe cruciferarum as there was delay in symptoms and reduced disease severity than non-transgenic plants. In addition, the rate of disease spreading to uninfected or distal parts was also delayed in transgenic plants thus suggesting the activation of SAR. Altogether, the present study suggests that BjNPR1 is involved in broad spectrum of disease resistance against fungal pathogens.
Full Text Available Chronic nonhealing wounds have been heralded as a silent epidemic, causing significant morbidity and mortality especially in elderly, diabetic, and obese populations. Polymicrobial biofilms in the wound bed are hypothesized to disrupt the highly coordinated and sequential events of cutaneous healing. Both culture-dependent and -independent studies of the chronic-wound microbiome have almost exclusively focused on bacteria, omitting what we hypothesize are important fungal contributions to impaired healing and the development of complications. Here we show for the first time that fungal communities (the mycobiome in chronic wounds are predictive of healing time, associated with poor outcomes, and form mixed fungal-bacterial biofilms. We longitudinally profiled 100, nonhealing diabetic-foot ulcers with high-throughput sequencing of the pan-fungal internal transcribed spacer 1 (ITS1 locus, estimating that up to 80% of wounds contain fungi, whereas cultures performed in parallel captured only 5% of colonized wounds. The “mycobiome” was highly heterogeneous over time and between subjects. Fungal diversity increased with antibiotic administration and onset of a clinical complication. The proportions of the phylum Ascomycota were significantly greater (P = 0.015 at the beginning of the study in wounds that took >8 weeks to heal. Wound necrosis was distinctly associated with pathogenic fungal species, while taxa identified as allergenic filamentous fungi were associated with low levels of systemic inflammation. Directed culturing of wounds stably colonized by pathogens revealed that interkingdom biofilms formed between yeasts and coisolated bacteria. Combined, our analyses provide enhanced resolution of the mycobiome during impaired wound healing, its role in chronic disease, and impact on clinical outcomes.
Kingsley, Mark T.
The threat to American interests from terrorists is not limited to attacks against humans. Terrorists might seek to inflict damage to the U.S. economy by attacking our agricultural sector. Infection of commodity crops by bacterial or fungal crop pathogens could adversely impact U.S. agriculture, either directly from damage to crops or indirectly from damage to our ability to export crops suspected of contamination. Recognizing a terrorist attack against U.S. agriculture, to be able to prosecute the terrorists, is among the responsibilities of the members of Hazardous Material Response Unit (HMRU) of the Federal Bureau of Investigation (FBI). Nucleic acid analysis of plant pathogen strains by the use of polymerase chain reaction (PCR) amplification techniques is a powerful method for determining the exact identity of pathogens, as well as their possible region of origin. This type of analysis, however, requires that PCR assays be developed specific to each particular pathogen strain, and analysis protocols developed that are specific to the particular instrument used for detection. The objectives of the work described here were threefold: 1) to assess the potential terrorist threat to U.S. agricultural crops, 2) to determine whether suitable assays exist to monitor that threat, and 3) where assays are needed for priority plant pathogen threats, to modify or develop those assays for use by specialists at the HMRU. The assessment of potential threat to U.S. commodity crops and the availability of assays for those threats were described in detail in the Technical Requirements Document (9) and will be summarized in this report. This report addresses development of specific assays identified in the Technical Requirements Document, and offers recommendations for future development to ensure that HMRU specialists will be prepared with the PCR assays they need to protect against the threat of economic terrorism.
Manuel Francisco Rodríguez Saldaña
Full Text Available This research took place at the Provincial Plant Sanitation Laboratory, in Camaguey, Cuba, between September 2013 and September 2015. The in vitro compatibility and antagonistic capacity of Trichoderma harzianum Rifai (strain A-34 on rice pathogens (Bipolaris oryzae Breda de Haan, Sarocladium oryzae (Sawada w., Gams and D. Hawksworth and Magnaporthe grisea (Hebert Barr, was determined against pesticides used on rice. Assessment using traditional methods of microbiological isolation of mycelial growth, sporulation and conidial germination of the antagonist, to determine if the action mechanisms (antibiosis, competence, parasitism against fungal pathogens, was made between 24 and 216 hours of application. A bifactorial design in dual culture was used for statistical analysis, along with scales for determination of microbial antagonistic capacity. Active ingredients tebuconazol + procloraz, trifloxistrobin+ ciproconazole, and epoxiconazole + kresoxim-methyl, affected mycelial growth of the antagonist. Moreover, the antagonist against active ingredients carbendazim, copper oxychloride, azoxystrobin and tebuconazo + triadimenol showed mycelial growth, sporulation and pathogen interaction, affecting their growth by means of coiling, penetration, granulation, and cell lysis, between 96 and 216 hours.
Full Text Available Abstract Background Nonhost resistance (NHR provides immunity to all members of a plant species against all isolates of a microorganism that is pathogenic to other plant species. Three Arabidopsis thaliana PEN (penetration deficient genes, PEN1, 2 and 3 have been shown to provide NHR against the barley pathogen Blumeria graminis f. sp. hordei at the prehaustorial level. Arabidopsis pen1-1 mutant lacking the PEN1 gene is penetrated by the hemibiotrophic oomycete pathogen Phytophthora sojae, the causal organism of the root and stem rot disease in soybean. We investigated if there is any novel nonhost resistance mechanism in Arabidopsis against the soybean pathogen, P. sojae. Results The P.sojaesusceptible (pss 1 mutant was identified by screening a mutant population created in the Arabidopsis pen1-1 mutant that lacks penetration resistance against the non adapted barley biotrophic fungal pathogen, Blumeria graminis f. sp. hordei. Segregation data suggested that PEN1 is not epistatic to PSS1. Responses of pss1 and pen1-1 to P. sojae invasion were distinct and suggest that PSS1 may act at both pre- and post-haustorial levels, while PEN1 acts at the pre-haustorial level against this soybean pathogen. Therefore, PSS1 encodes a new form of nonhost resistance. The pss1 mutant is also infected by the necrotrophic fungal pathogen, Fusarium virguliforme, which causes sudden death syndrome in soybean. Thus, a common NHR mechanism is operative in Arabidopsis against both hemibiotrophic oomycetes and necrotrophic fungal pathogens that are pathogenic to soybean. However, PSS1 does not play any role in immunity against the bacterial pathogen, Pseudomonas syringae pv. glycinea, that causes bacterial blight in soybean. We mapped PSS1 to a region very close to the southern telomere of chromosome 3 that carries no known disease resistance genes. Conclusions The study revealed that Arabidopsis PSS1 is a novel nonhost resistance gene that confers a new form of
Sumit, Rishi; Sahu, Binod B; Xu, Min; Sandhu, Devinder; Bhattacharyya, Madan K
Nonhost resistance (NHR) provides immunity to all members of a plant species against all isolates of a microorganism that is pathogenic to other plant species. Three Arabidopsis thaliana PEN (penetration deficient) genes, PEN1, 2 and 3 have been shown to provide NHR against the barley pathogen Blumeria graminis f. sp. hordei at the prehaustorial level. Arabidopsis pen1-1 mutant lacking the PEN1 gene is penetrated by the hemibiotrophic oomycete pathogen Phytophthora sojae, the causal organism of the root and stem rot disease in soybean. We investigated if there is any novel nonhost resistance mechanism in Arabidopsis against the soybean pathogen, P. sojae. The P.sojaesusceptible (pss) 1 mutant was identified by screening a mutant population created in the Arabidopsis pen1-1 mutant that lacks penetration resistance against the non adapted barley biotrophic fungal pathogen, Blumeria graminis f. sp. hordei. Segregation data suggested that PEN1 is not epistatic to PSS1. Responses of pss1 and pen1-1 to P. sojae invasion were distinct and suggest that PSS1 may act at both pre- and post-haustorial levels, while PEN1 acts at the pre-haustorial level against this soybean pathogen. Therefore, PSS1 encodes a new form of nonhost resistance. The pss1 mutant is also infected by the necrotrophic fungal pathogen, Fusarium virguliforme, which causes sudden death syndrome in soybean. Thus, a common NHR mechanism is operative in Arabidopsis against both hemibiotrophic oomycetes and necrotrophic fungal pathogens that are pathogenic to soybean. However, PSS1 does not play any role in immunity against the bacterial pathogen, Pseudomonas syringae pv. glycinea, that causes bacterial blight in soybean. We mapped PSS1 to a region very close to the southern telomere of chromosome 3 that carries no known disease resistance genes. The study revealed that Arabidopsis PSS1 is a novel nonhost resistance gene that confers a new form of nonhost resistance against both a hemibiotrophic oomycete
Gamaletsou, Maria N; Walsh, Thomas J; Sipsas, Nikolaos V
Invasive fungal infections caused by drug-resistant organisms are an emerging threat to heavily immunosuppressed patients with hematological malignancies. Modern early antifungal treatment strategies, such as prophylaxis and empirical and preemptive therapy, result in long-term exposure to antifungal agents, which is a major driving force for the development of resistance. The extended use of central venous catheters, the nonlinear pharmacokinetics of certain antifungal agents, neutropenia, other forms of intense immunosuppression, and drug toxicities are other contributing factors. The widespread use of agricultural and industrial fungicides with similar chemical structures and mechanisms of action has resulted in the development of environmental reservoirs for some drug-resistant fungi, especially azole-resistant Aspergillus species, which have been reported from four continents. The majority of resistant strains have the mutation TR34/L98H, a finding suggesting that the source of resistance is the environment. The global emergence of new fungal pathogens with inherent resistance, such as Candida auris, is a new public health threat. The most common mechanism of antifungal drug resistance is the induction of efflux pumps, which decrease intracellular drug concentrations. Overexpression, depletion, and alteration of the drug target are other mechanisms of resistance. Mutations in the ERG11 gene alter the protein structure of C-demethylase, reducing the efficacy of antifungal triazoles. Candida species become echinocandin-resistant by mutations in FKS genes. A shift in the epidemiology of Candida towards resistant non-albicans Candida spp. has emerged among patients with hematological malignancies. There is no definite association between antifungal resistance, as defined by elevated minimum inhibitory concentrations, and clinical outcomes in this population. Detection of genes or mutations conferring resistance with the use of molecular methods may offer better
Maria N. Gamaletsou
Full Text Available Invasive fungal infections caused by drug-resistant organisms are an emerging threat to heavily immunosuppressed patients with hematological malignancies. Modern early antifungal treatment strategies, such as prophylaxis and empirical and preemptive therapy, result in long-term exposure to antifungal agents, which is a major driving force for the development of resistance. The extended use of central venous catheters, the nonlinear pharmacokinetics of certain antifungal agents, neutropenia, other forms of intense immunosuppression, and drug toxicities are other contributing factors. The widespread use of agricultural and industrial fungicides with similar chemical structures and mechanisms of action has resulted in the development of environmental reservoirs for some drug-resistant fungi, especially azole-resistant Aspergillus species, which have been reported from four continents. The majority of resistant strains have the mutation TR34/L98H, a finding suggesting that the source of resistance is the environment. The global emergence of new fungal pathogens with inherent resistance, such as Candida auris, is a new public health threat. The most common mechanism of antifungal drug resistance is the induction of efflux pumps, which decrease intracellular drug concentrations. Overexpression, depletion, and alteration of the drug target are other mechanisms of resistance. Mutations in the ERG11 gene alter the protein structure of C-demethylase, reducing the efficacy of antifungal triazoles. Candida species become echinocandin-resistant by mutations in FKS genes. A shift in the epidemiology of Candida towards resistant non-albicans Candida spp. has emerged among patients with hematological malignancies. There is no definite association between antifungal resistance, as defined by elevated minimum inhibitory concentrations, and clinical outcomes in this population. Detection of genes or mutations conferring resistance with the use of molecular methods
Cooper, Sarah; Agnew, Linda; Pereg, Lily
Control of soilborne fungal root pathogens that severely compromise cotton production and other crops worldwide has historically been through the use of synthetic fungicides and fertilizers, these often have hazardous implications for environmental and soil health. The search for sustainable alternatives has lead to heightened interest in biocontrol, using soil microorganisms that suppress the growth of phytopathogens directly and biofertilization, the use of microorganisms to increasing the nutrient availability in soils, increasing seedling vigour. Soil properties and consequently soil microbial properties are strongly impacted by agricultural practices, therefore we are isolating indigenous microorganisms from soils collected from ten different geographical locations within the Australian cotton-growing region. These differ vastly in soil type and management practices. Soils are being analysed to compare the abundance of phosphate solubilising, auxin producing and nitrogen cycling bacteria. Rhizospheric bacteria capable of plant growth promoting through a multiple actions are being isolated. In addition, a method for isolating soilborne fungal suppressive microbes directly from soil samples has been designed and is currently being used. Comparisons between agricultural practices and the plant growth promoting microbial component of soil microbiome will be reported on. We will discuss the microbial isolates identified, their modes of action and their potential use as biocontrol agents and/or biofertilizers in Australian cotton growing soils.
Paterson, R Russell M; Lima, Nelson
Disease caused by filamentous fungal human pathogens (FFHP) is increasing. These organisms cause severe mycoses in immunosuppressed individuals, such as those: (a) with AIDS; (b) having undergone transplantation; and/or (c) undergoing chemotherapy. Immunocompetent people can become infected. Some FFHP are isolated from foods which may be fomites. However, the information concerning particular species on specific food is large, dispersed and difficult to obtain. Reports of filamentous fungi from food/crops and causing human disease are frequently only available in the literature of food mycology/plant pathology and medical mycology, respectively: it is seldom cross-referenced. Aspergillus contains some species with strains that are the most dangerous FFHP, with Aspergillus fumigatus causing the most serious diseases. Fusarium and Mucor also contain species of high importance and approximately 15 other genera are involved. A checklist and database of FFHP species isolated from food is presented herein with emphasis on Aspergillus , Fusarium and Mucor in summary tables to increase awareness of the connection between food and FFHP. Metadata on all FFHP is provided in a large supplementary table for updating and revision when necessary. Previous names of fungi have been revised to reflect current valid usage whenever appropriate. The information will form a foundation for future research and taxonomic revisions in the field. The paper will be highly useful for medical practitioners, food mycologists, fungal taxonomists, patients, regulators and food producers interested in reducing infectious diseases and producing high quality food.
Full Text Available This research aims to control Seedling damping off disease in plants by using antagonistic actinomycetes against the causative fungi. Phytophthora infestans was isolated from the infected tomato plant seedling obtained from an economic plant nursery in Amphoe Pak Chong, Nakhon Ratchasima Province, Thailand. The chitinolytic Streptomyces rubrolavendulae S4, isolated from termite mounds at the grove of Amphoe Si-Sawat, Kanchanaburi Province, Thailand, was proven to be the most effective growth inhibition of fungal pathogens tested on potato dextrose agar. Tomato and chili seedlings that colonized with antagonistic S. rubrolavendulae S4 were grown in P. infestans artificial inoculated peat moss. Percents of noninfested seedling in fungal contaminated peat moss were compared to the controls with uninoculated peat moss. In P. infestans contaminated peat moss, the percents of survival of tomato and chili seedling were significantly increased (0.05. It was clearly demonstrated that S. rubrolavendulae S4 can prevent the tomato and chili seedling damping off disease in economic plant nurseries.
Douglas, Lois M.; Konopka, James. B.
Candida albicans is a human fungal pathogen capable of causing lethal systemic infections. The plasma membrane plays key roles in virulence because it not only functions as a protective barrier, it also mediates dynamic functions including secretion of virulence factors, cell wall synthesis, invasive hyphal morphogenesis, endocytosis, and nutrient uptake. Consistent with this functional complexity, the plasma membrane is composed of a wide array of lipids and proteins. These components are organized into distinct domains that will be the topic of this review. Some of the plasma membrane domains that will be described are known to act as scaffolds or barriers to diffusion, such as MCC/eisosomes, septins, and sites of contact with the endoplasmic reticulum. Other zones mediate dynamic processes, including secretion, endocytosis, and a special region at hyphal tips that facilitates rapid growth. The highly organized architecture of the plasma membrane facilitates the coordination of diverse functions and promotes the pathogenesis of C. albicans. PMID:26920878
Oscar Eduardo Ladino Rey
Full Text Available Research about filamentous fungal oil palm pathogens is as essential for the maintenance and the sustainability of the crop as the conservation of these identified fungi itself because it allows its uses for former researches or as a guide for identify fungi through time. The purpose of this study was to evaluate two methods of conservation, one of them in three times sterilized distilled water (ADTE and with Glicerol 10 %. By four months, with a monthly review of fungi isolated from plant tissue palm oil affected by Aspergillus sp., Chrysosporium sp., Curvularia sp., Fusarium sp., Penicillium sp. and Rhizopus sp. Six of the seven fungi strains conserved were successfully recovered from the Treatment with Glicerol 10 %, while five of the seven strains conserved ADTE were recovered after the four evaluation months of this study.
Full Text Available Objective: To evaluate the antifungal activity of seaweed extracts against human fungal pathogens. Methods: Antifungal activity of six species of marine macro algae Codium decorticatum, Caulerpa scalpelliformis, Gracilaria crassa, Acanthophora spicifera, Sargassum wightii and Turbinaria conoides using different solvents acetone, methanol, chloroform, diethyl ether, ethyl acetate, hexane and aqueous were evaluated against Fusarium oxysporum, Fusarium udum, Fusarium solani, Rhizoctonia solani, Alternaria alternat, Botrytis cinerea, Candida albicans, Candida krusei, Aspergillus niger and Aspergillus flavus. Results: From the investigation, the maximum activity was recorded from Phaeophyceae, Chlorophyceae and Rhodophyceae respectively. The maximum inhibition zone was noted in acetone extract of T. conoides against F. udum. Conclusions: From these findings, it is concluded that brown seaweed Turbinaria conoides is more effective than the green and red seaweeds.
Dean R Paini
Full Text Available Predicting future species invasions presents significant challenges to researchers and government agencies. Simply considering the vast number of potential species that could invade an area can be insurmountable. One method, recently suggested, which can analyse large datasets of invasive species simultaneously is that of a self organising map (SOM, a form of artificial neural network which can rank species by establishment likelihood. We used this method to analyse the worldwide distribution of 486 fungal pathogens and then validated the method by creating a virtual world of invasive species in which to test the SOM. This novel validation method allowed us to test SOM's ability to rank those species that can establish above those that can't. Overall, we found the SOM highly effective, having on average, a 96-98% success rate (depending on the virtual world parameters. We also found that regions with fewer species present (i.e. 1-10 species were more difficult for the SOM to generate an accurately ranked list, with success rates varying from 100% correct down to 0% correct. However, we were able to combine the numbers of species present in a region with clustering patterns in the SOM, to further refine confidence in lists generated from these sparsely populated regions. We then used the results from the virtual world to determine confidences for lists generated from the fungal pathogen dataset. Specifically, for lists generated for Australia and its states and territories, the reliability scores were between 84-98%. We conclude that a SOM analysis is a reliable method for analysing a large dataset of potential invasive species and could be used by biosecurity agencies around the world resulting in a better overall assessment of invasion risk.
Dang, Ha X; Pryor, Barry; Peever, Tobin; Lawrence, Christopher B
Alternaria is considered one of the most common saprophytic fungal genera on the planet. It is comprised of many species that exhibit a necrotrophic phytopathogenic lifestyle. Several species are clinically associated with allergic respiratory disorders although rarely found to cause invasive infections in humans. Finally, Alternaria spp. are among the most well known producers of diverse fungal secondary metabolites, especially toxins. We have recently sequenced and annotated the genomes of 25 Alternaria spp. including but not limited to many necrotrophic plant pathogens such as A. brassicicola (a pathogen of Brassicaceous crops like cabbage and canola) and A. solani (a major pathogen of Solanaceous plants like potato and tomato), and several saprophytes that cause allergy in human such as A. alternata isolates. These genomes were annotated and compared. Multiple genetic differences were found in the context of plant and human pathogenicity, notably the pro-inflammatory potential of A. alternata. The Alternaria genomes database was built to provide a public platform to access the whole genome sequences, genome annotations, and comparative genomics data of these species. Genome annotation and comparison were performed using a pipeline that integrated multiple computational and comparative genomics tools. Alternaria genome sequences together with their annotation and comparison data were ported to Ensembl database schemas using a self-developed tool (EnsImport). Collectively, data are currently hosted using a customized installation of the Ensembl genome browser platform. Recent efforts in fungal genome sequencing have facilitated the studies of the molecular basis of fungal pathogenicity as a whole system. The Alternaria genomes database provides a comprehensive resource of genomics and comparative data of an important saprophytic and plant/human pathogenic fungal genus. The database will be updated regularly with new genomes when they become available. The
Diseases of crop plants may lead to considerable yield losses. To control fungal diseases, fungicides are used extensively in present-day agricultural production. In order to reduce such external inputs, cultivars with natural resistance to important fungal pathogens are recommended in systems of integrated plant protection. Basic research, including genetics and molecular methods, is required to elucidate the mechanisms by which plants react to an attack by fungal pathogens and successfully defend themselves. This review examines our knowledge with respect to the multicomponent systems of resistance in plants, using powdery mildew on barley as an example. In addition, the question is adressed whether systemic acquired resistance and plants with transgenic resistance may be utilized in future plant protection strategies.
Full Text Available Sclerotinia sclerotiorum and Botrytis cinerea are closely related necrotrophic plant pathogenic fungi notable for their wide host ranges and environmental persistence. These attributes have made these species models for understanding the complexity of necrotrophic, broad host-range pathogenicity. Despite their similarities, the two species differ in mating behaviour and the ability to produce asexual spores. We have sequenced the genomes of one strain of S. sclerotiorum and two strains of B. cinerea. The comparative analysis of these genomes relative to one another and to other sequenced fungal genomes is provided here. Their 38-39 Mb genomes include 11,860-14,270 predicted genes, which share 83% amino acid identity on average between the two species. We have mapped the S. sclerotiorum assembly to 16 chromosomes and found large-scale co-linearity with the B. cinerea genomes. Seven percent of the S. sclerotiorum genome comprises transposable elements compared to <1% of B. cinerea. The arsenal of genes associated with necrotrophic processes is similar between the species, including genes involved in plant cell wall degradation and oxalic acid production. Analysis of secondary metabolism gene clusters revealed an expansion in number and diversity of B. cinerea-specific secondary metabolites relative to S. sclerotiorum. The potential diversity in secondary metabolism might be involved in adaptation to specific ecological niches. Comparative genome analysis revealed the basis of differing sexual mating compatibility systems between S. sclerotiorum and B. cinerea. The organization of the mating-type loci differs, and their structures provide evidence for the evolution of heterothallism from homothallism. These data shed light on the evolutionary and mechanistic bases of the genetically complex traits of necrotrophic pathogenicity and sexual mating. This resource should facilitate the functional studies designed to better understand what makes these
Benito, Ernesto P.; Couloux, Arnaud; Coutinho, Pedro M.; de Vries, Ronald P.; Dyer, Paul S.; Fillinger, Sabine; Fournier, Elisabeth; Gout, Lilian; Hahn, Matthias; Kohn, Linda; Lapalu, Nicolas; Plummer, Kim M.; Pradier, Jean-Marc; Quévillon, Emmanuel; Sharon, Amir; Simon, Adeline; ten Have, Arjen; Tudzynski, Bettina; Tudzynski, Paul; Wincker, Patrick; Andrew, Marion; Anthouard, Véronique; Beffa, Rolland; Benoit, Isabelle; Bouzid, Ourdia; Brault, Baptiste; Chen, Zehua; Choquer, Mathias; Collémare, Jérome; Cotton, Pascale; Danchin, Etienne G.; Da Silva, Corinne; Gautier, Angélique; Giraud, Corinne; Giraud, Tatiana; Gonzalez, Celedonio; Grossetete, Sandrine; Güldener, Ulrich; Henrissat, Bernard; Howlett, Barbara J.; Kodira, Chinnappa; Kretschmer, Matthias; Lappartient, Anne; Leroch, Michaela; Levis, Caroline; Mauceli, Evan; Neuvéglise, Cécile; Oeser, Birgitt; Pearson, Matthew; Poulain, Julie; Poussereau, Nathalie; Quesneville, Hadi; Rascle, Christine; Schumacher, Julia; Ségurens, Béatrice; Sexton, Adrienne; Silva, Evelyn; Sirven, Catherine; Soanes, Darren M.; Talbot, Nicholas J.; Templeton, Matt; Yandava, Chandri; Yarden, Oded; Zeng, Qiandong; Rollins, Jeffrey A.; Lebrun, Marc-Henri; Dickman, Marty
Sclerotinia sclerotiorum and Botrytis cinerea are closely related necrotrophic plant pathogenic fungi notable for their wide host ranges and environmental persistence. These attributes have made these species models for understanding the complexity of necrotrophic, broad host-range pathogenicity. Despite their similarities, the two species differ in mating behaviour and the ability to produce asexual spores. We have sequenced the genomes of one strain of S. sclerotiorum and two strains of B. cinerea. The comparative analysis of these genomes relative to one another and to other sequenced fungal genomes is provided here. Their 38–39 Mb genomes include 11,860–14,270 predicted genes, which share 83% amino acid identity on average between the two species. We have mapped the S. sclerotiorum assembly to 16 chromosomes and found large-scale co-linearity with the B. cinerea genomes. Seven percent of the S. sclerotiorum genome comprises transposable elements compared to cinerea. The arsenal of genes associated with necrotrophic processes is similar between the species, including genes involved in plant cell wall degradation and oxalic acid production. Analysis of secondary metabolism gene clusters revealed an expansion in number and diversity of B. cinerea–specific secondary metabolites relative to S. sclerotiorum. The potential diversity in secondary metabolism might be involved in adaptation to specific ecological niches. Comparative genome analysis revealed the basis of differing sexual mating compatibility systems between S. sclerotiorum and B. cinerea. The organization of the mating-type loci differs, and their structures provide evidence for the evolution of heterothallism from homothallism. These data shed light on the evolutionary and mechanistic bases of the genetically complex traits of necrotrophic pathogenicity and sexual mating. This resource should facilitate the functional studies designed to better understand what makes these fungi such successful and
Full Text Available Fungal plant pathogens are major threats to food security worldwide. Sclerotinia sclerotiorum and Botrytis cinerea are closely related Ascomycete plant pathogens causing mold diseases on hundreds of plant species. There is no genetic source of complete plant resistance to these broad host range pathogens known to date. Instead, natural plant populations show a continuum of resistance levels controlled by multiple genes, a phenotype designated as quantitative disease resistance. Little is known about the molecular mechanisms controlling the interaction between plants and S. sclerotiorum and B. cinerea but significant advances were made on this topic in the last years. This minireview highlights a selection of nine themes that emerged in recent research reports on the molecular bases of plant-S. sclerotiorum and plant-B. cinerea interactions. On the fungal side, this includes progress on understanding the role of oxalic acid, on the study of fungal small secreted proteins. Next, we discuss the exchanges of small RNA between organisms and the control of cell death in plant and fungi during pathogenic interactions. Finally on the plant side, we highlight defense priming by mechanical signals, the characterization of plant Receptor-like proteins and the hormone abscisic acid in the response to B. cinerea and S. sclerotiorum , the role of plant general transcription machinery and plant small bioactive peptides. These represent nine trends we selected as remarkable in our understanding of fungal molecules causing disease and plant mechanisms associated with disease resistance to two devastating broad host range fungi.
Biere, A.; Antonovics, J.
Costs of resistance are often invoked to explain the maintenance of polymorphisms for resistance to fungal pathogens in natural plant populations. To investigate such costs, 27 half-sib families of Silene alba, collected from a single host population, were grown in experiment populations in the
Schuck, Stefan; Weinhold, Arne; Luu, Van Thi; Baldwin, Ian T
The wild tobacco species Nicotiana attenuata has been intensively used as a model plant to study its interaction with insect herbivores and pollinators in nature, however very little is known about its native pathogen community. We describe a fungal disease outbreak in a native N. attenuata population comprising 873 plants growing in an area of about 1500 m2. The population was divided into 14 subpopulations and disease symptom development in the subpopulations was monitored for 16 days, revealing a waxing and waning of visible disease symptoms with some diseased plants recovering fully. Native fungal N. attenuata pathogens were isolated from diseased plants, characterized genetically, chemotaxonomically and morphologically, revealing several isolates of the ascomycete genera Fusarium and Alternaria, that differed in the type and strength of the disease symptoms they caused in bioassays on either detached leaves or intact soil-grown plants. These isolates and the bioassays will empower the study of N. attenuata-pathogen interactions in a realistic ecological context.
Carly R. Muletz-Wolz
Full Text Available Symbiotic bacteria may dampen the impacts of infectious diseases on hosts by inhibiting pathogen growth. However, our understanding of the generality of pathogen inhibition by different bacterial taxa across pathogen genotypes and environmental conditions is limited. Bacterial inhibitory properties are of particular interest for the amphibian-killing fungal pathogens (Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans, for which probiotic applications as conservation strategies have been proposed. We quantified the inhibition strength of five putatively B. dendrobatidis-inhibitory bacteria isolated from woodland salamander skin against six Batrachochytrium genotypes at two temperatures (12 and 18°C. We selected six genotypes from across the Batrachochytrium phylogeny: B. salamandrivorans, B. dendrobatidis-Brazil and four genotypes of the B. dendrobatidis Global Panzootic Lineage (GPL1: JEL647, JEL404; GPL2: SRS810, JEL423. We performed 96-well plate challenge assays in a full factorial design. We detected a Batrachochytrium genotype by temperature interaction on bacterial inhibition score for all bacteria, indicating that bacteria vary in ability to inhibit Batrachochytrium depending on pathogen genotype and temperature. Acinetobacter rhizosphaerae moderately inhibited B. salamandrivorans at both temperatures (μ = 46–53%, but not any B. dendrobatidis genotypes. Chryseobacterium sp. inhibited three Batrachochytrium genotypes at both temperatures (μ = 5–71%. Pseudomonas sp. strain 1 inhibited all Batrachochytrium genotypes at 12°C and four Batrachochytrium genotypes at 18°C (μ = 5–100%. Pseudomonas sp. strain 2 and Stenotrophomonas sp. moderately to strongly inhibited all six Batrachochytrium genotypes at both temperatures (μ = 57–100%. All bacteria consistently inhibited B. salamandrivorans. Using cluster analysis of inhibition scores, we found that more closely related Batrachochytrium genotypes grouped together
Dianella Iglesias Rodrígue
Full Text Available Solanum lycopersicum L. is often attacked by fungal pathogens like Fusarium oxysporum Schlee, Alternaria solani Sor, Passarola fulva (Cooke U. Braun and Crous, Botritys cinerea Pers, Rhizoctonia solani Khün and Sclerotium rolfsii Sacc. The phytosanitary control of these diseases is commonly executed by synthetic fungicides that increase the production cost and cause intense problems to the environment and damage human health. It is necessary to find new cheaper alternatives and with low environmental impact like vegetal extracts. In this research, a review about the use of vegetal extracts against tomato pathogens was made, focusing on the tested vegetal specie, the way to determine the antifungal activity and the evaluated fungus. The bibliographic research covered the period 2003-2013 and it was consulted 54 articles of journals indexed in specialized databases of international and Latin American acceptance. The most evaluated vegetal extracts by the investigators were those related to the leaves of Azadirachta indica A. Juss and Allium sativum L., the most studied fungus was R. solani. In the majority of cases, the antifungal activity was only determined in vitro conditions
Amin, A.; Shah, S.; Khan, M.A.; Khan, M.M.
The antimicrobial and antifungal activities of crude extracts of Ziziphus mauritiana leaves were investigated against six selected bacterial (Staphylococcus aureus, Micrococcus luteus, Escherichia coli, Pseudomonas aeruginosa, Enterobacter, Klebsiella pneumoniae) and one fungal pathogen (Aspel-gillus niger). The crude extract was further fractionated in butanol, choloroform, n-hexane and methanol. Agar well diffusion and agar dilution assay were employed for determination of zones of inhibition and MICs, respectively, whereas MBC was determined using broth dilution test. The butanol fraction presented encouraging antimicrobial activity (15.0%0.02), while methanol (7.03:1:0.05) and chloroform (7.0%0,05) fractions emerged with significantly low susceptibility. The n-hexane fraction was recorded as almost inactive (0%0) against all bacterial pathogens. Unlike the antibacterial activities, all fractions possessed momentous antifungal activities except the methanol fraction (0%0). The n-hexane fraction showed widest zone of inhibition (11:1:0.05) followed by butanol (8.0%0.02) and chloroform (7.0%0.02). (author)
Braunstein, S.; Cheng, T.
The fungal pathogen Geomyces destructans (Gd) causes the disease White-nose Syndrome (WNS) in bats and is estimated to have killed millions of bats since its emergence in North America in 2006. Gd is predicted to cause the local extinction of at least three bat species if rates of decline continue unabated. Given the devastating impacts of Gd to bat populations, identifying a viable method for controlling the pathogen is pertinent for conservation of affected bat species. Our work focuses on identifying naturally-occurring skin bacteria on bats that are antagonistic to Gd that could potentially be used as a biocontrol. We cultured bacteria from skin swabs taken from wild bats (Myotis lucifugus, Eptesicus fuscus, Myotis sodalis, Perimyotis subflavus). We conducted challenge experiments to identify bacterial strains that inhibited Gd growth. Bacteria that exhibited antifungal properties were identified using 16S and gyrB markers. Our methods identified several bacteria in the Pseudomonas fluorescens complex as potential biocontrol agents. Future work will continue to test the viability of these bacteria as biocontrol agents via experimental treatments with live captive bats. The failure of previous non-biocontrol methods highlights the importance of developing these bacteria as a biologically-friendly method for controlling Gd. A bat infected with Geomyces destructans. Photo by West Virginia Division of Natural Resources Bacterial culture from the swab of a bat's wings
Full Text Available The objective of this study is to evaluate Lotus japonicus transcriptomic responses to arbuscular mycorrhizal (AM germinated spore exudates (GSE, responsible for activating nuclear Ca2+ spiking in plant root epidermis. A microarray experiment was performed comparing gene expression in Lotus rootlets treated with GSE or water after 24 h and 48 h. The transcriptional pattern of selected genes that resulted to be regulated in the array was further evaluated upon different treatments and timings. In particular, Lotus rootlets were treated with: GSE from the pathogenic fungus Colletotrichum trifolii; short chitin oligomers (acknowledged AM fungal signals and long chitin oligomers (as activators of pathogenic responses. This experimental set up has revealed that AM GSE generates a strong transcriptomic response in Lotus roots with an extensive defense-related response after 24 hours and a subsequent downregulation after 48 hours. A similar subset of defense-related genes resulted to be upregulated also upon treatment with C. trifolii GSE, although with an opposite trend. Surprisingly, long chitin oligomers activated both defense-like and symbiosis-related genes. Among the genes regulated in the microarray, promoter-GUS assay showed that LjMATE1 activates in epidermal cells and root hairs.
Horbach, Ralf; Graf, Alexander; Weihmann, Fabian; Antelo, Luis; Mathea, Sebastian; Liermann, Johannes C; Opatz, Till; Thines, Eckhard; Aguirre, Jesús; Deising, Holger B
In filamentous fungi, Sfp-type 4'-phosphopantetheinyl transferases (PPTases) activate enzymes involved in primary (alpha-aminoadipate reductase [AAR]) and secondary (polyketide synthases and nonribosomal peptide synthetases) metabolism. We cloned the PPTase gene PPT1 of the maize anthracnose fungus Colletotrichum graminicola and generated PPTase-deficient mutants (Deltappt1). Deltappt1 strains were auxotrophic for Lys, unable to synthesize siderophores, hypersensitive to reactive oxygen species, and unable to synthesize polyketides (PKs). A differential analysis of secondary metabolites produced by wild-type and Deltappt1 strains led to the identification of six novel PKs. Infection-related morphogenesis was affected in Deltappt1 strains. Rarely formed appressoria of Deltappt1 strains were nonmelanized and ruptured on intact plant. The hyphae of Deltappt1 strains colonized wounded maize (Zea mays) leaves but failed to generate necrotic anthracnose disease symptoms and were defective in asexual sporulation. To analyze the pleiotropic pathogenicity phenotype, we generated AAR-deficient mutants (Deltaaar1) and employed a melanin-deficient mutant (M1.502). Results indicated that PPT1 activates enzymes required at defined stages of infection. Melanization is required for cell wall rigidity and appressorium function, and Lys supplied by the AAR1 pathway is essential for necrotrophic development. As PPTase-deficient mutants of Magnaporthe oryzea were also nonpathogenic, we conclude that PPTases represent a novel fungal pathogenicity factor.
Full Text Available The aim of this study was to study the prevalence of Salmonella spp., Listeria spp., Staphylococcus spp. and E. coli in the raw cow milk. In this study 133 milk-tank samples from several milk collecting points were analysed. After the tests the following prevalence was detected: for Listeria spp. 13 positive samples (9.77%, with 9 Listeria monocytogenes samples confirmed (6.76%. Salmonella spp. was not detected in any of the the samples. The biggest presence was detected for Staphylococcus spp. with 113 positive samples (85.0%. Further testes has shown prevalence of coagulase-positive staphylococci of 73% (97 positive samples. Escherichia coli was confirmed in 57 samples (46.0%. The results from this study clearly indicate that pathogen microorganisms which are important for the human health can be found in the raw cow milk and their presence can be potential hazard for contamination of the milk-processing establishments.
Mims, C. W.; Celio, Gail J.; Richardson, Elizabeth A.
This article reports on the use of high pressure freezing followed by freeze substitution (HPF/FS) to study ultrastructural details of host pathogen interactions in fungal diseases of plants. The specific host pathogen systems discussed here include a powdery mildew infection of poinsettia and rust infections of daylily and Indian strawberry. The three pathogens considered here all attack the leaves of their hosts and produce specialized hyphal branches known as haustoria that invade individual host cells without killing them. We found that HPF/FS provided excellent preservation of both haustoria and host cells for all three host pathogen systems. Preservation of fungal and host cell membranes was particularly good and greatly facilitated the detailed study of host pathogen interfaces. In some instances, HPF/FS provided information that was not available in samples prepared for study using conventional chemical fixation. On the other hand, we did encounter various problems associated with the use of HPF/FS. Examples included freeze damage of samples, inconsistency of fixation in different samples, separation of plant cell cytoplasm from cell walls, breakage of cell walls and membranes, and splitting of thin sections. However, we believe that the outstanding preservation of ultrastructural details afforded by HPF/FS significantly outweighs these problems and we highly recommend the use of this fixation protocol for future studies of fungal host-plant interactions.
Full Text Available Fungal pathogens can be lethal, especially among immunocompromised populations, such as patients with AIDS and recipients of tissue transplantation or chemotherapy. Prolonged usage of antifungal reagents can lead to drug resistance and treatment failure. Understanding mechanisms that underlie drug resistance by pathogenic microorganisms is thus vital for dealing with this emerging issue. In this study, we show that dramatic sequence changes in PDR5, an ABC (ATP-binding cassette efflux transporter protein gene in an opportunistic fungal pathogen, caused the organism to become hypersensitive to azole, a widely used antifungal drug. Surprisingly, the same mutations conferred growth advantages to the organism on polyenes, which are also commonly used antimycotics. Our results indicate that Pdr5p might be important for ergosterol homeostasis. The observed remarkable sequence divergence in the PDR5 gene in yeast strain YJM789 may represent an interesting case of adaptive loss of gene function with significant clinical implications.
Kim, Sang Yoon; Lee, Sang Yeob; Weon, Hang-Yeon; Sang, Mee Kyung; Song, Jaekyeong
Bacillus species have been widely used as biological control agents in agricultural fields due to their ability to suppress plant pathogens. Bacillus velezensis M75 was isolated from cotton waste used for mushroom cultivation in Korea, and was found to be antagonistic to fungal plant pathogens. Here, we report the complete genome sequence of the M75 strain, which has a 4,007,450-bp single circular chromosome with 3921 genes and a G+C content of 46.60%. The genome contained operons encoding various non-ribosomal peptide synthetases and polyketide synthases, which are responsible for the biosynthesis of secondary metabolites. Our results will provide a better understanding of the genome of B. velezensis strains for their application as biocontrol agents against fungal plant pathogens in agricultural fields. Copyright © 2016 Elsevier B.V. All rights reserved.
Ding, Yezhang; Huffaker, Alisa; Köllner, Tobias G; Weckwerth, Philipp; Robert, Christelle A M; Spencer, Joseph L; Lipka, Alexander E; Schmelz, Eric A
To ensure food security, maize ( Zea mays ) is a model crop for understanding useful traits underlying stress resistance. In contrast to foliar biochemicals, root defenses limiting the spread of disease remain poorly described. To better understand belowground defenses in the field, we performed root metabolomic profiling and uncovered unexpectedly high levels of the sesquiterpene volatile β-selinene and the corresponding nonvolatile antibiotic derivative β-costic acid. The application of metabolite-based quantitative trait locus mapping using biparental populations, genome-wide association studies, and near-isogenic lines enabled the identification of terpene synthase21 ( ZmTps21 ) on chromosome 9 as a β-costic acid pathway candidate gene. Numerous closely examined β-costic acid-deficient inbred lines were found to harbor Zmtps21 pseudogenes lacking conserved motifs required for farnesyl diphosphate cyclase activity. For biochemical validation, a full-length ZmTps21 was cloned, heterologously expressed in Escherichia coli , and demonstrated to cyclize farnesyl diphosphate, yielding β-selinene as the dominant product. Consistent with microbial defense pathways, ZmTps21 transcripts strongly accumulate following fungal elicitation. Challenged field roots containing functional ZmTps21 alleles displayed β-costic acid levels over 100 μg g -1 fresh weight, greatly exceeding in vitro concentrations required to inhibit the growth of five different fungal pathogens and rootworm larvae ( Diabrotica balteata ). In vivo disease resistance assays, using ZmTps21 and Zmtps21 near-isogenic lines, further support the endogenous antifungal role of selinene-derived metabolites. Involved in the biosynthesis of nonvolatile antibiotics, ZmTps21 exists as a useful gene for germplasm improvement programs targeting optimized biotic stress resistance. © 2017 American Society of Plant Biologists. All Rights Reserved.
Full Text Available Abstract Background Grosmannia clavigera is a bark beetle-vectored fungal pathogen of pines that causes wood discoloration and may kill trees by disrupting nutrient and water transport. Trees respond to attacks from beetles and associated fungi by releasing terpenoid and phenolic defense compounds. It is unclear which genes are important for G. clavigera's ability to overcome antifungal pine terpenoids and phenolics. Results We constructed seven cDNA libraries from eight G. clavigera isolates grown under various culture conditions, and Sanger sequenced the 5' and 3' ends of 25,000 cDNA clones, resulting in 44,288 high quality ESTs. The assembled dataset of unique transcripts (unigenes consists of 6,265 contigs and 2,459 singletons that mapped to 6,467 locations on the G. clavigera reference genome, representing ~70% of the predicted G. clavigera genes. Although only 54% of the unigenes matched characterized proteins at the NCBI database, this dataset extensively covers major metabolic pathways, cellular processes, and genes necessary for response to environmental stimuli and genetic information processing. Furthermore, we identified genes expressed in spores prior to germination, and genes involved in response to treatment with lodgepole pine phloem extract (LPPE. Conclusions We provide a comprehensively annotated EST dataset for G. clavigera that represents a rich resource for gene characterization in this and other ophiostomatoid fungi. Genes expressed in response to LPPE treatment are indicative of fungal oxidative stress response. We identified two clusters of potentially functionally related genes responsive to LPPE treatment. Furthermore, we report a simple method for identifying contig misassemblies in de novo assembled EST collections caused by gene overlap on the genome.
Lau, Anna; Sorrell, Tania C.; Chen, Sharon; Stanley, Keith; Iredell, Jonathan; Halliday, Catriona
We describe the first development and evaluation of a rapid multiplex tandem PCR (MT-PCR) assay for the detection and identification of fungi directly from blood culture specimens that have been flagged as positive. The assay uses a short-cycle multiplex amplification, followed by 12 simultaneous PCRs which target the fungal internal transcribed spacer 1 (ITS1) and ITS2 region, elongation factor 1-α (EF1-α), and β-tubulin genes to identify 11 fungal pathogens: Candida albicans, Candida dublin...
Full Text Available In eukaryotes, microbodies called peroxisomes play important roles in cellular activities during the life cycle. Previous studies indicate that peroxisomal functions are important for plant infection in many phytopathogenic fungi, but detailed relationships between fungal pathogenicity and peroxisomal function still remain unclear. Here we report the importance of peroxisomal protein import through PTS2 (Peroxisomal Targeting Signal 2 in fungal development and pathogenicity of Magnaporthe oryzae. Using an Agrobacterium tumefaciens-mediated transformation library, a pathogenicity-defective mutant was isolated from M. oryzae and identified as a T-DNA insert in the PTS2 receptor gene, MoPEX7. Gene disruption of MoPEX7 abolished peroxisomal localization of a thiolase (MoTHL1 containing PTS2, supporting its role in the peroxisomal protein import machinery. ΔMopex7 showed significantly reduced mycelial growth on media containing short-chain fatty acids as a sole carbon source. ΔMopex7 produced fewer conidiophores and conidia, but conidial germination was normal. Conidia of ΔMopex7 were able to develop appressoria, but failed to cause disease in plant cells, except after wound inoculation. Appressoria formed by ΔMopex7 showed a defect in turgor generation due to a delay in lipid degradation and increased cell wall porosity during maturation. Taken together, our results suggest that the MoPEX7-mediated peroxisomal matrix protein import system is required for fungal development and pathogenicity M. oryzae.
Gauthier, Gregory M; Keller, Nancy P
The outbreak of fungal meningitis associated with contaminated methylprednisolone acetate has thrust the importance of fungal infections into the public consciousness. The predominant pathogen isolated from clinical specimens, Exserohilum rostratum (teleomorph: Setosphaeria rostrata), is a dematiaceous fungus that infects grasses and rarely humans. This outbreak highlights the potential for fungal pathogens to infect both plants and humans. Most crossover or trans-kingdom pathogens are soil saprophytes and include fungi in Ascomycota and Mucormycotina phyla. To establish infection, crossover fungi must overcome disparate, host-specific barriers, including protective surfaces (e.g. cuticle, skin), elevated temperature, and immune defenses. This review illuminates the underlying mechanisms used by crossover fungi to cause infection in plants and mammals, and highlights critical events that lead to human infection by these pathogens. Several genes including veA, laeA, and hapX are important in regulating biological processes in fungi important for both invasive plant and animal infections. Copyright © 2013 Elsevier Inc. All rights reserved.
Full Text Available A critical step in the life cycle of many fungal pathogens is the transition between yeast-like growth and the formation of filamentous structures, a process known as dimorphism. This morphological shift, typically triggered by multiple environmental signals, is tightly controlled by complex genetic pathways to ensure successful pathogenic development. In animal pathogenic fungi, one of the best known regulators of dimorphism is the general transcriptional repressor, Tup1. However, the role of Tup1 in fungal dimorphism is completely unknown in plant pathogens. Here we show that Tup1 plays a key role in orchestrating the yeast to hypha transition in the maize pathogen Ustilago maydis. Deletion of the tup1 gene causes a drastic reduction in the mating and filamentation capacity of the fungus, in turn leading to a reduced virulence phenotype. In U. maydis, these processes are controlled by the a and b mating-type loci, whose expression depends on the Prf1 transcription factor. Interestingly, Δtup1 strains show a critical reduction in the expression of prf1 and that of Prf1 target genes at both loci. Moreover, we observed that Tup1 appears to regulate Prf1 activity by controlling the expression of the prf1 transcriptional activators, rop1 and hap2. Additionally, we describe a putative novel prf1 repressor, named Pac2, which seems to be an important target of Tup1 in the control of dimorphism and virulence. Furthermore, we show that Tup1 is required for full pathogenic development since tup1 deletion mutants are unable to complete the sexual cycle. Our findings establish Tup1 as a key factor coordinating dimorphism in the phytopathogen U. maydis and support a conserved role for Tup1 in the control of hypha-specific genes among animal and plant fungal pathogens.
Full Text Available Most fungal pathogens of humans display robust protective oxidative stress responses that contribute to their pathogenicity. The induction of enzymes that detoxify reactive oxygen species (ROS is an essential component of these responses. We showed previously that ectopic expression of the heme-containing catalase enzyme in Candida albicans enhances resistance to oxidative stress, combinatorial oxidative plus cationic stress, and phagocytic killing. Clearly ectopic catalase expression confers fitness advantages in the presence of stress, and therefore in this study we tested whether it enhances fitness in the absence of stress. We addressed this using a set of congenic barcoded C. albicans strains that include doxycycline-conditional tetON-CAT1 expressors. We show that high basal catalase levels, rather than CAT1 induction following stress imposition, reduce ROS accumulation and cell death, thereby promoting resistance to acute peroxide or combinatorial stress. This conclusion is reinforced by our analyses of phenotypically diverse clinical isolates and the impact of stochastic variation in catalase expression upon stress resistance in genetically homogeneous C. albicans populations. Accordingly, cat1Δ cells are more sensitive to neutrophil killing. However, we find that catalase inactivation does not attenuate C. albicans virulence in mouse or invertebrate models of systemic candidiasis. Furthermore, our direct comparisons of fitness in vitro using isogenic barcoded CAT1, cat1Δ and tetON-CAT1 strains show that, while ectopic catalase expression confers a fitness advantage during peroxide stress, it confers a fitness defect in the absence of stress. This fitness defect is suppressed by iron supplementation. Also high basal catalase levels induce key iron assimilatory functions (CFL5, FET3, FRP1, FTR1. We conclude that while high basal catalase levels enhance peroxide stress resistance, they place pressure on iron homeostasis through an
Full Text Available The increasing level of hazardous residues in the environment and food chains has led the European Union to restrict the use of chemical fungicides. Thus, exploiting new natural antagonistic microorganisms against fungal diseases could serve the agricultural production to reduce pre- and post-harvest losses, to boost safer practices for workers and to protect the consumers' health. The main aim of this work was to evaluate the antagonistic potential of epiphytic yeasts against Botrytis cinerea, Aspergillus carbonarius, and Penicillium expansum pathogen species. In particular, yeast isolation was carried out from grape berries of Vitis vinifera ssp sylvestris populations, of the Eurasian area, and V. vinifera ssp vinifera cultivars from three different farming systems (organic, biodynamic, and conventional. Strains able to inhibit or slow the growth of pathogens were selected by in vitro and in vivo experiments. The most effective antagonist yeast strains were subsequently assayed for their capability to colonize the grape berries. Finally, possible modes of action, such as nutrients and space competition, iron depletion, cell wall degrading enzymes, diffusible and volatile antimicrobial compounds, and biofilm formation, were investigated as well. Two hundred and thirty-one yeast strains belonging to 26 different species were isolated; 20 of them, ascribed to eight species, showed antagonistic action against all molds. Yeasts isolated from V. vinifera ssp sylvestris were more effective (up to 50% against B. cinerea rather than those isolated from V. vinifera ssp vinifera. Six strains, all isolated from wild vines, belonging to four species (Meyerozyma guilliermondii, Hanseniaspora uvarum, Hanseniaspora clermontiae, and Pichia kluyveri revealed one or more phenotypical characteristics associated to the analyzed modes of antagonistic action.
Risk, Joanna M; Selter, Liselotte L; Chauhan, Harsh; Krattinger, Simon G; Kumlehn, Jochen; Hensel, Goetz; Viccars, Libby A; Richardson, Terese M; Buesing, Gabriele; Troller, Anna; Lagudah, Evans S; Keller, Beat
The Lr34 gene encodes an ABC transporter and has provided wheat with durable, broad-spectrum resistance against multiple fungal pathogens for over 100 years. Because barley does not have an Lr34 ortholog, we expressed Lr34 in barley to investigate its potential as a broad-spectrum resistance resource in another grass species. We found that introduction of the genomic Lr34 sequence confers resistance against barley leaf rust and barley powdery mildew, two pathogens specific for barley but not virulent on wheat. In addition, the barley lines showed enhanced resistance against wheat stem rust. Transformation with the Lr34 cDNA or the genomic susceptible Lr34 allele did not result in increased resistance. Unlike wheat, where Lr34-conferred resistance is associated with adult plants, the genomic Lr34 transgenic barley lines exhibited multipathogen resistance in seedlings. These transgenic barley lines also developed leaf tip necrosis (LTN) in young seedlings, which correlated with an up-regulation of senescence marker genes and several pathogenesis-related (PR) genes. In wheat, transcriptional expression of Lr34 is highest in adult plants and correlates with increased resistance and LTN affecting the last emerging leaf. The severe phenotype of transgenic Lr34 barley resulted in reduced plant growth and total grain weight. These results demonstrate that Lr34 provides enhanced multipathogen resistance early in barley plant development and implies the conservation of the substrate and mechanism of the LR34 transporter and its molecular action between wheat and barley. With controlled gene expression, the use of Lr34 may be valuable for many cereal breeding programmes, particularly given its proven durability. © 2013 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.
Holland, Linda M.; Schröder, Markus S.; Turner, Siobhán A.; Taff, Heather; Andes, David; Grózer, Zsuzsanna; Gácser, Attila; Ames, Lauren; Haynes, Ken; Higgins, Desmond G.; Butler, Geraldine
Candida parapsilosis and Candida albicans are human fungal pathogens that belong to the CTG clade in the Saccharomycotina. In contrast to C. albicans, relatively little is known about the virulence properties of C. parapsilosis, a pathogen particularly associated with infections of premature neonates. We describe here the construction of C. parapsilosis strains carrying double allele deletions of 100 transcription factors, protein kinases and species-specific genes. Two independent deletions were constructed for each target gene. Growth in >40 conditions was tested, including carbon source, temperature, and the presence of antifungal drugs. The phenotypes were compared to C. albicans strains with deletions of orthologous transcription factors. We found that many phenotypes are shared between the two species, such as the role of Upc2 as a regulator of azole resistance, and of CAP1 in the oxidative stress response. Others are unique to one species. For example, Cph2 plays a role in the hypoxic response in C. parapsilosis but not in C. albicans. We found extensive divergence between the biofilm regulators of the two species. We identified seven transcription factors and one protein kinase that are required for biofilm development in C. parapsilosis. Only three (Efg1, Bcr1 and Ace2) have similar effects on C. albicans biofilms, whereas Cph2, Czf1, Gzf3 and Ume6 have major roles in C. parapsilosis only. Two transcription factors (Brg1 and Tec1) with well-characterized roles in biofilm formation in C. albicans do not have the same function in C. parapsilosis. We also compared the transcription profile of C. parapsilosis and C. albicans biofilms. Our analysis suggests the processes shared between the two species are predominantly metabolic, and that Cph2 and Bcr1 are major biofilm regulators in C. parapsilosis. PMID:25233198
Pradhan, Arnab; Herrero-de-Dios, Carmen; Belmonte, Rodrigo; Budge, Susan; Lopez Garcia, Angela; Kolmogorova, Aljona; Lee, Keunsook K; Martin, Brennan D; Ribeiro, Antonio; Bebes, Attila; Yuecel, Raif; Gow, Neil A R; Munro, Carol A; MacCallum, Donna M; Quinn, Janet; Brown, Alistair J P
Most fungal pathogens of humans display robust protective oxidative stress responses that contribute to their pathogenicity. The induction of enzymes that detoxify reactive oxygen species (ROS) is an essential component of these responses. We showed previously that ectopic expression of the heme-containing catalase enzyme in Candida albicans enhances resistance to oxidative stress, combinatorial oxidative plus cationic stress, and phagocytic killing. Clearly ectopic catalase expression confers fitness advantages in the presence of stress, and therefore in this study we tested whether it enhances fitness in the absence of stress. We addressed this using a set of congenic barcoded C. albicans strains that include doxycycline-conditional tetON-CAT1 expressors. We show that high basal catalase levels, rather than CAT1 induction following stress imposition, reduce ROS accumulation and cell death, thereby promoting resistance to acute peroxide or combinatorial stress. This conclusion is reinforced by our analyses of phenotypically diverse clinical isolates and the impact of stochastic variation in catalase expression upon stress resistance in genetically homogeneous C. albicans populations. Accordingly, cat1Δ cells are more sensitive to neutrophil killing. However, we find that catalase inactivation does not attenuate C. albicans virulence in mouse or invertebrate models of systemic candidiasis. Furthermore, our direct comparisons of fitness in vitro using isogenic barcoded CAT1, cat1Δ and tetON-CAT1 strains show that, while ectopic catalase expression confers a fitness advantage during peroxide stress, it confers a fitness defect in the absence of stress. This fitness defect is suppressed by iron supplementation. Also high basal catalase levels induce key iron assimilatory functions (CFL5, FET3, FRP1, FTR1). We conclude that while high basal catalase levels enhance peroxide stress resistance, they place pressure on iron homeostasis through an elevated cellular demand
José F Muñoz
Full Text Available Three closely related thermally dimorphic pathogens are causal agents of major fungal diseases affecting humans in the Americas: blastomycosis, histoplasmosis and paracoccidioidomycosis. Here we report the genome sequence and analysis of four strains of the etiological agent of blastomycosis, Blastomyces, and two species of the related genus Emmonsia, typically pathogens of small mammals. Compared to related species, Blastomyces genomes are highly expanded, with long, often sharply demarcated tracts of low GC-content sequence. These GC-poor isochore-like regions are enriched for gypsy elements, are variable in total size between isolates, and are least expanded in the avirulent B. dermatitidis strain ER-3 as compared with the virulent B. gilchristii strain SLH14081. The lack of similar regions in related species suggests these isochore-like regions originated recently in the ancestor of the Blastomyces lineage. While gene content is highly conserved between Blastomyces and related fungi, we identified changes in copy number of genes potentially involved in host interaction, including proteases and characterized antigens. In addition, we studied gene expression changes of B. dermatitidis during the interaction of the infectious yeast form with macrophages and in a mouse model. Both experiments highlight a strong antioxidant defense response in Blastomyces, and upregulation of dioxygenases in vivo suggests that dioxide produced by antioxidants may be further utilized for amino acid metabolism. We identify a number of functional categories upregulated exclusively in vivo, such as secreted proteins, zinc acquisition proteins, and cysteine and tryptophan metabolism, which may include critical virulence factors missed before in in vitro studies. Across the dimorphic fungi, loss of certain zinc acquisition genes and differences in amino acid metabolism suggest unique adaptations of Blastomyces to its host environment. These results reveal the dynamics
Muñoz, José F; Gauthier, Gregory M; Desjardins, Christopher A; Gallo, Juan E; Holder, Jason; Sullivan, Thomas D; Marty, Amber J; Carmen, John C; Chen, Zehua; Ding, Li; Gujja, Sharvari; Magrini, Vincent; Misas, Elizabeth; Mitreva, Makedonka; Priest, Margaret; Saif, Sakina; Whiston, Emily A; Young, Sarah; Zeng, Qiandong; Goldman, William E; Mardis, Elaine R; Taylor, John W; McEwen, Juan G; Clay, Oliver K; Klein, Bruce S; Cuomo, Christina A
Three closely related thermally dimorphic pathogens are causal agents of major fungal diseases affecting humans in the Americas: blastomycosis, histoplasmosis and paracoccidioidomycosis. Here we report the genome sequence and analysis of four strains of the etiological agent of blastomycosis, Blastomyces, and two species of the related genus Emmonsia, typically pathogens of small mammals. Compared to related species, Blastomyces genomes are highly expanded, with long, often sharply demarcated tracts of low GC-content sequence. These GC-poor isochore-like regions are enriched for gypsy elements, are variable in total size between isolates, and are least expanded in the avirulent B. dermatitidis strain ER-3 as compared with the virulent B. gilchristii strain SLH14081. The lack of similar regions in related species suggests these isochore-like regions originated recently in the ancestor of the Blastomyces lineage. While gene content is highly conserved between Blastomyces and related fungi, we identified changes in copy number of genes potentially involved in host interaction, including proteases and characterized antigens. In addition, we studied gene expression changes of B. dermatitidis during the interaction of the infectious yeast form with macrophages and in a mouse model. Both experiments highlight a strong antioxidant defense response in Blastomyces, and upregulation of dioxygenases in vivo suggests that dioxide produced by antioxidants may be further utilized for amino acid metabolism. We identify a number of functional categories upregulated exclusively in vivo, such as secreted proteins, zinc acquisition proteins, and cysteine and tryptophan metabolism, which may include critical virulence factors missed before in in vitro studies. Across the dimorphic fungi, loss of certain zinc acquisition genes and differences in amino acid metabolism suggest unique adaptations of Blastomyces to its host environment. These results reveal the dynamics of genome evolution
was investigated. In this PhD work it could be shown that light dependent disease symptoms were associated with less fungal colonization, while suppressing the rate of photosynthesis by keeping plants in darkness made them super-susceptible to B. sorokiniana colonization. Likewise, partial suppression......The fungal pathogen Bipolaris sorokiniana causes a wide spectrum of diseases including spot blotch disease. To achieve a better understanding of the biology of the fungus, the interaction of B. sorokiniana with the host barley (Hordeum vulgare L) and the resulting disease spot blotch...... of photosynthesis with DCMU (3-(3,4-Dichlorophenyl)-1,1-dimethylurea) reduced the formation of necrosis after infection and led to increased susceptibility, strongly implying that active photosynthesis is involved in disease symptom formation and that these symptoms negatively affect fungal colonization...
Starkey, Lindsay A; Newton, Kassie; Brunker, Jill; Crowdis, Kelly; Edourad, Emile Jean Pierre; Meneus, Pedro; Little, Susan E
Canine vector-borne pathogens are common on some Caribbean islands, but survey data in Haiti are lacking. To determine the prevalence of selected vector-borne pathogens in dogs from Haiti, we tested blood samples collected from 210 owned dogs, 28 (13.3%) of which were infested with Rhipicephalus sanguineus ticks at the time of blood collection. No other tick species were identified on these dogs. A commercially available ELISA identified antibodies to Ehrlichia spp. in 69 (32.9%), antibodies to Anaplasma spp. in 37 (17.6%), and antigen of Dirofilaria immitis in 55 (26.2%); antibodies to Borrelia burgdorferi were not detected in any sample. Molecular assays of whole blood from 207 of the dogs confirmed infection with Ehrlichia canis (15; 7.2%), Anaplasma platys (13; 6.3%), D. immitis (46; 22.2%), Wolbachia spp. (45; 21.7%), Babesia vogeli (16; 7.7%), and Hepatozoon canis (40; 19.3%), but Anaplasma phagocytophilum, Babesia canis, Babesia rossi, Babesia gibsoni, Ehrlichia chaffeensis, Ehrlichia ewingii, or Hepatozoon americanum were not detected. Co-infection with two or more vector-borne pathogens was detected by serology in 42 (20.0%) dogs and by molecular assays in 22 (10.6%) dogs; one dog was co-infected with B. vogeli and E. canis as detected by PCR with D. immitis detected by serology (antigen). Overall, evidence of past or current infection with at least one vector-borne pathogen was identified in 142/210 (67.6%) dogs in this study, underscoring the common nature of these pathogens, some of which are zoonotic, in Haiti. Copyright © 2016 Elsevier B.V. All rights reserved.
Murray, Damian R; Schaller, Mark; Suedfeld, Peter
According to a "parasite stress" hypothesis, authoritarian governments are more likely to emerge in regions characterized by a high prevalence of disease-causing pathogens. Recent cross-national evidence is consistent with this hypothesis, but there are inferential limitations associated with that evidence. We report two studies that address some of these limitations, and provide further tests of the hypothesis. Study 1 revealed that parasite prevalence strongly predicted cross-national differences on measures assessing individuals' authoritarian personalities, and this effect statistically mediated the relationship between parasite prevalence and authoritarian governance. The mediation result is inconsistent with an alternative explanation for previous findings. To address further limitations associated with cross-national comparisons, Study 2 tested the parasite stress hypothesis on a sample of traditional small-scale societies (the Standard Cross-Cultural Sample). Results revealed that parasite prevalence predicted measures of authoritarian governance, and did so even when statistically controlling for other threats to human welfare. (One additional threat-famine-also uniquely predicted authoritarianism.) Together, these results further substantiate the parasite stress hypothesis of authoritarianism, and suggest that societal differences in authoritarian governance result, in part, from cultural differences in individuals' authoritarian personalities.
Lau, Anna; Sorrell, Tania C; Chen, Sharon; Stanley, Keith; Iredell, Jonathan; Halliday, Catriona
We describe the first development and evaluation of a rapid multiplex tandem PCR (MT-PCR) assay for the detection and identification of fungi directly from blood culture specimens that have been flagged as positive. The assay uses a short-cycle multiplex amplification, followed by 12 simultaneous PCRs which target the fungal internal transcribed spacer 1 (ITS1) and ITS2 region, elongation factor 1-alpha (EF1-alpha), and beta-tubulin genes to identify 11 fungal pathogens: Candida albicans, Candida dubliniensis, Candida glabrata, Candida guilliermondii, Candida krusei, Candida parapsilosis complex, Candida tropicalis, Cryptococcus neoformans complex, Fusarium solani, Fusarium species, and Scedosporium prolificans. The presence or absence of a fungal target was confirmed by melting curve analysis. Identification by MT-PCR correlated with culture-based identification for 44 (100%) patients. No cross-reactivity was detected in 200 blood culture specimens that contained bacteria or in 30 blood cultures without microorganisms. Fungi were correctly identified in five specimens with bacterial coinfection and in blood culture samples that were seeded with a mixture of yeast cells. The MT-PCR assay was able to provide rapid (detection and identification of fungal pathogens directly from blood culture specimens.
Full Text Available Along with barley and rice, maize provides staple food for more than half of the world population. Maize ears are regularly infected with fungal pathogens of the Fusarium genus, which, besides reducing yield, also taint grains with toxic metabolites. In an earlier work, we have shown that maize ears infection with single Fusarium strains was detectable through volatile sensing. In nature, infection most commonly occurs with more than a single fungal strain; hence we tested how the interactions of two strains would modulate volatile emission from infected ears. For this purpose, ears of a hybrid and a dwarf maize variety were simultaneously infected with different strains of F. graminearums and F. verticillioides and, the resulting volatile profiles were compared to the ones of ears infected with single strains. Disease severity, fungal biomass and the concentration of an oxylipin 9-hydroxy octadecadienoic acid, a signaling molecule involved in plant defense, were monitored and correlated to volatile profiles. Our results demonstrate that in simultaneous infections of hybrid and dwarf maize, the most competitive fungal strains had the largest influence on the volatile profile of infected ears. In both concurrent and single inoculations, volatile profiles reflected disease severity. Additionally, the data further indicate that dwarf maize and hybrid maize might emit common (i.e. sesquiterpenoids and specific markers upon fungal infection. Overall this suggests that volatile profiles might be a good proxy for disease severity regardless of the fungal competition taking place in maize ears. With the appropriate sensitivity and reliability, volatile sensing thus appears as a promising tool for detecting fungal infection of maize ears under field conditions.
Zihalirwa Kulimushi, Parent; Arg?elles Arias, Anthony; Franzil, Laurent; Steels, S?bastien; Ongena, Marc
Most isolates belonging to the Bacillus amyloliquefaciens subsp. plantarum clade retain the potential to produce a vast array of structurally diverse antimicrobial compounds that largely contribute to their efficacy as biocontrol agents against numerous plant fungal pathogens. In that context, the role of cyclic lipopeptides (CLPs) has been well-documented but still little is known about the impact of interactions with other soil-inhabiting microbes on the expression of these molecules. In th...
Lee, Soo Chan; Billmyre, R Blake; Li, Alicia; Carson, Sandra; Sykes, Sean M; Huh, Eun Young; Mieczkowski, Piotr; Ko, Dennis C; Cuomo, Christina A; Heitman, Joseph
Food-borne pathogens are ongoing problems, and new pathogens are emerging. The impact of fungi, however, is largely underestimated. Recently, commercial yogurts contaminated with Mucor circinelloides were sold, and >200 consumers became ill with nausea, vomiting, and diarrhea. Mucoralean fungi cause the fatal fungal infection mucormycosis, whose incidence has been continuously increasing. In this study, we isolated an M. circinelloides strain from a yogurt container, and multilocus sequence typing identified the strain as Mucor circinelloides f. circinelloides. M. circinelloides f. circinelloides is the most virulent M. circinelloides subspecies and is commonly associated with human infections, whereas M. circinelloides f. lusitanicus and M. circinelloides f. griseocyanus are less common causes of infection. Whole-genome analysis of the yogurt isolate confirmed it as being close to the M. circinelloides f. circinelloides subgroup, with a higher percentage of divergence with the M. circinelloides f. lusitanicus subgroup. In mating assays, the yogurt isolate formed sexual zygospores with the (-) M. circinelloides f. circinelloides tester strain, which is congruent with its sex locus encoding SexP, the (+) mating type sex determinant. The yogurt isolate was virulent in murine and wax moth larva host systems. In a murine gastromucormycosis model, Mucor was recovered from fecal samples of infected mice for up to 10 days, indicating that Mucor can survive transit through the GI tract. In interactions with human immune cells, M. circinelloides f. lusitanicus induced proinflammatory cytokines but M. circinelloides f. circinelloides did not, which may explain the different levels of virulence in mammalian hosts. This study demonstrates that M. circinelloides can spoil food products and cause gastrointestinal illness in consumers and may pose a particular risk to immunocompromised patients. Importance: The U.S. FDA reported that yogurt products were contaminated with M
Helliwell, Emily E; Vega-Arreguín, Julio; Shi, Zi; Bailey, Bryan; Xiao, Shunyuan; Maximova, Siela N; Tyler, Brett M; Guiltinan, Mark J
The internalization of some oomycete and fungal pathogen effectors into host plant cells has been reported to be blocked by proteins that bind to the effectors' cell entry receptor, phosphatidylinositol-3-phosphate (PI3P). This finding suggested a novel strategy for disease control by engineering plants to secrete PI3P-binding proteins. In this study, we tested this strategy using the chocolate tree Theobroma cacao. Transient expression and secretion of four different PI3P-binding proteins in detached leaves of T. cacao greatly reduced infection by two oomycete pathogens, Phytophthora tropicalis and Phytophthora palmivora, which cause black pod disease. Lesion size and pathogen growth were reduced by up to 85%. Resistance was not conferred by proteins lacking a secretory leader, by proteins with mutations in their PI3P-binding site, or by a secreted PI4P-binding protein. Stably transformed, transgenic T. cacao plants expressing two different PI3P-binding proteins showed substantially enhanced resistance to both P. tropicalis and P. palmivora, as well as to the fungal pathogen Colletotrichum theobromicola. These results demonstrate that secretion of PI3P-binding proteins is an effective way to increase disease resistance in T. cacao, and potentially in other plants, against a broad spectrum of pathogens. © 2015 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.
Misra, Rajesh Chandra; Sandeep; Kamthan, Mohan; Kumar, Santosh; Ghosh, Sumit
Plant often responds to fungal pathogens by expressing a group of proteins known as pathogenesis-related proteins (PRs). The expression of PR is mediated through pathogen-induced signal-transduction pathways that are fine-tuned by phytohormones such as methyl jasmonate (MeJA). Here, we report functional characterization of an Ocimum basilicum PR5 family member (ObTLP1) that was identified from a MeJA-responsive expression sequence tag collection. ObTLP1 encodes a 226 amino acid polypeptide that showed sequence and structural similarities with a sweet-tasting protein thaumatin of Thaumatococcus danielli and also with a stress-responsive protein osmotin of Nicotiana tabacum. The expression of ObTLP1 in O. basilicum was found to be organ-preferential under unstressed condition, and responsive to biotic and abiotic stresses, and multiple phytohormone elicitations. Bacterially-expressed recombinant ObTLP1 inhibited mycelial growth of the phytopathogenic fungi, Scleretonia sclerotiorum and Botrytis cinerea; thereby, suggesting its antifungal activity. Ectopic expression of ObTLP1 in Arabidopsis led to enhanced tolerance to S. sclerotiorum and B. cinerea infections, and also to dehydration and salt stress. Moreover, induced expression of the defense marker genes suggested up-regulation of the defense-response pathways in ObTLP1-expressing Arabidopsis upon fungal challenge. Thus, ObTLP1 might be useful for providing tolerance to the fungal pathogens and abiotic stresses in crops.
Nowara, Daniela; Gay, Alexandra; Lacomme, Christophe; Shaw, Jane; Ridout, Christopher; Douchkov, Dimitar; Hensel, Götz; Kumlehn, Jochen; Schweizer, Patrick
Powdery mildew fungi are obligate biotrophic pathogens that only grow on living hosts and cause damage in thousands of plant species. Despite their agronomical importance, little direct functional evidence for genes of pathogenicity and virulence is currently available because mutagenesis and transformation protocols are lacking. Here, we show that the accumulation in barley (Hordeum vulgare) and wheat (Triticum aestivum) of double-stranded or antisense RNA targeting fungal transcripts affects the development of the powdery mildew fungus Blumeria graminis. Proof of concept for host-induced gene silencing was obtained by silencing the effector gene Avra10, which resulted in reduced fungal development in the absence, but not in the presence, of the matching resistance gene Mla10. The fungus could be rescued from the silencing of Avra10 by the transient expression of a synthetic gene that was resistant to RNA interference (RNAi) due to silent point mutations. The results suggest traffic of RNA molecules from host plants into B. graminis and may lead to an RNAi-based crop protection strategy against fungal pathogens. PMID:20884801
Gebregiorgis, Firehun; Struik, P.C.; Lantinga, E.A.; Tessema, Taye
Water hyacinth poses serious socio-economic and environmental problems in Ethiopia. To integrate fungal pathogens into water hyacinth management, a survey was conducted in the Rift Valley of Ethiopia. Based on morphological characterization and DNA sequencing, 25 fungal species were identified
Full Text Available Mitogen-activated protein kinases (MAPKs have been demonstrated to be involved in fungal development, sexual reproduction, pathogenicity and/or virulence in many filamentous plant pathogenic fungi, but genes for MAPKs in the fungal cereal pathogen Bipolaris sorokiniana have not been characterized. In this study, orthologues of three MAPK genes (CsSLT2, CsHOG1 and CsFUS3 and one MAPK kinase kinase (MAPKKK gene (CsSTE11 were identified in the whole genome sequence of the B. sorokiniana isolate ND90Pr, and knockout mutants were generated for each of them. The ∆Csfus3 and ∆Csste11 mutants were defective in conidiation and formation of appressoria-like structures, showed hypersensitivity to oxidative stress and lost pathogenicity on non-wounded leaves of barley cv. Bowman. When inoculated on wounded leaves of Bowman, the ∆Csfus3 and ∆Csste11 mutants were reduced in virulence compared to the wild type. No morphological changes were observed in the ∆Cshog1 mutants in comparison with the wild type; however, they were slightly reduced in growth under oxidative stress and were hypersensitive to hyperosmotic stress. The ∆Cshog1 mutants formed normal appressoria-like structures but were reduced in virulence when inoculated on Bowman leaves. The ∆Csslt2 mutants produced more vegetative hyphae, had lighter pigmentation, were more sensitive to cell wall degrading enzymes, and were reduced in virulence on Bowman leaves, although they formed normal appressoria like the wild type. Root infection assays indicated that the ∆Cshog1 and ∆Csslt2 mutants were able to infect barley roots while the ∆Csfus3 and ∆Csste11 failed to cause any symptoms. However, no significant difference in virulence was observed for ∆Cshog1 mutants while ∆Csslt2 mutants showed significantly reduced virulence on barley roots in comparison with the wild type. Our results indicated that all of these MAPK and MAPKKK genes are involved in the regulation of fungal
Li, He; Zhou, Guo-Ying; Liu, Jun-Ang; Xu, Jianping
The filamentous fungus Colletotrichum fructicola is found in all five continents and is capable of causing severe diseases in a number of economically important plants such as avocado, fig, cocoa, pear, and tea-oil trees. However, almost nothing is known about its patterns of genetic variation and epidemiology on any of its host plant species. Here we analyzed 167 isolates of C. fructicola obtained from the leaves of tea-oil tree Camellia oleifera at 15 plantations in seven Chinese provinces. Multilocus sequence typing was conducted for all isolates based on DNA sequences at fragments of four genes: the internal transcribed spacers of the nuclear ribosomal RNA gene cluster (539 bp), calmodulin (633 bp), glutamine synthetase (711 bp), and glyceraldehyde-3-phosphate dehydrogenase (190 bp), yielding 3.52%, 0.63%, 8.44%, and 7.89% of single nucleotide polymorphic sites and resulting in 15, 5, 12 and 11 alleles respectively at the four gene fragments in the total sample. The combined allelic information from all four loci identified 53 multilocus genotypes with the most frequent represented by 21 isolates distributed in eight tea-oil plantations in three provinces, consistent with long-distance clonal dispersal. However, despite evidence for clonal dispersal, statistically significant genetic differentiation among geographic populations was detected. In addition, while no evidence of recombination was found within any of the four gene fragments, signatures of recombination were found among the four gene fragments in most geographic populations, consistent with sexual mating of this species in nature. Our study provides the first insights into the population genetics and epidemiology of the important plant fungal pathogen C. fructicola. PMID:27299731
Alexandre Morais do Amaral
Full Text Available The Dothideomycete fungus Mycosphaerella graminicola is the causal agent of Septoria tritici blotch, a devastating disease of wheat leaves that causes dramatic decreases in yield. Infection involves an initial extended period of symptomless intercellular colonisation prior to the development of visible necrotic disease lesions. Previous functional genomics and gene expression profiling studies have implicated the production of secreted virulence effector proteins as key facilitators of the initial symptomless growth phase. In order to identify additional candidate virulence effectors, we re-analysed and catalogued the predicted protein secretome of M. graminicola isolate IPO323, which is currently regarded as the reference strain for this species. We combined several bioinformatic approaches in order to increase the probability of identifying truly secreted proteins with either a predicted enzymatic function or an as yet unknown function. An initial secretome of 970 proteins was predicted, whilst further stringent selection criteria predicted 492 proteins. Of these, 321 possess some functional annotation, the composition of which may reflect the strictly intercellular growth habit of this pathogen, leaving 171 with no functional annotation. This analysis identified a protein family encoding secreted peroxidases/chloroperoxidases (PF01328 which is expanded within all members of the family Mycosphaerellaceae. Further analyses were done on the non-annotated proteins for size and cysteine content (effector protein hallmarks, and then by studying the distribution of homologues in 17 other sequenced Dothideomycete fungi within an overall total of 91 predicted proteomes from fungal, oomycete and nematode species. This detailed M. graminicola secretome analysis provides the basis for further functional and comparative genomics studies.
Full Text Available The filamentous fungus Colletotrichum fructicola is found in all five continents and is capable of causing severe diseases in a number of economically important plants such as avocado, fig, cocoa, pear, and tea-oil trees. However, almost nothing is known about its patterns of genetic variation and epidemiology on any of its host plant species. Here we analyzed 167 isolates of C. fructicola obtained from the leaves of tea-oil tree Camellia oleifera at 15 plantations in seven Chinese provinces. Multilocus sequence typing was conducted for all isolates based on DNA sequences at fragments of four genes: the internal transcribed spacers of the nuclear ribosomal RNA gene cluster (539 bp, calmodulin (633 bp, glutamine synthetase (711 bp, and glyceraldehyde-3-phosphate dehydrogenase (190 bp, yielding 3.52%, 0.63%, 8.44%, and 7.89% of single nucleotide polymorphic sites and resulting in 15, 5, 12 and 11 alleles respectively at the four gene fragments in the total sample. The combined allelic information from all four loci identified 53 multilocus genotypes with the most frequent represented by 21 isolates distributed in eight tea-oil plantations in three provinces, consistent with long-distance clonal dispersal. However, despite evidence for clonal dispersal, statistically significant genetic differentiation among geographic populations was detected. In addition, while no evidence of recombination was found within any of the four gene fragments, signatures of recombination were found among the four gene fragments in most geographic populations, consistent with sexual mating of this species in nature. Our study provides the first insights into the population genetics and epidemiology of the important plant fungal pathogen C. fructicola.
Olaide Olutoyin Oke
Full Text Available Fungal infections of the skin and nails are common global problems with attendant morbidity among affected individuals. Children are mostly affected due to predisposing factors such as overcrowding and low socioeconomic factors. The aim of this study was to determine the prevalence and the clinical patterns of superficial fungal infections among primary school children in Ile-Ife. A multistage sampling was conducted to select eight hundred pupils from ten primary schools in Ile-Ife. Data on epidemiological characteristics and clinical history was collected using a semistructured questionnaire and skin scrapings were done. The prevalence of superficial fungal infections among the 800 respondents was 35.0%. Male pupils constituted 51.0% of respondents while the females were 49.0%. The mean age for all the respondents was 9.42 ± 2.00. Tinea capitis was the commonest infection with a prevalence of 26.9% and tinea unguium, tinea corporis, and tinea faciei had a prevalence of 0.8%, 0.6%, and 0.5%, respectively. Tinea manuum had the least prevalence of 0.1%. Pityriasis versicolor had a prevalence of 4.4%. Microsporum audouinii was the leading organism isolated. The study shows that the prevalence of superficial fungal infection (SFI among primary school children in Ile-Ife is high with tinea capitis as the commonest SFI.
Oke, Olaide Olutoyin; Onayemi, Olaniyi; Olasode, Olayinka Abimbola; Omisore, Akinlolu Gabriel; Oninla, Olumayowa Abimbola
Fungal infections of the skin and nails are common global problems with attendant morbidity among affected individuals. Children are mostly affected due to predisposing factors such as overcrowding and low socioeconomic factors. The aim of this study was to determine the prevalence and the clinical patterns of superficial fungal infections among primary school children in Ile-Ife. A multistage sampling was conducted to select eight hundred pupils from ten primary schools in Ile-Ife. Data on epidemiological characteristics and clinical history was collected using a semistructured questionnaire and skin scrapings were done. The prevalence of superficial fungal infections among the 800 respondents was 35.0%. Male pupils constituted 51.0% of respondents while the females were 49.0%. The mean age for all the respondents was 9.42 ± 2.00. Tinea capitis was the commonest infection with a prevalence of 26.9% and tinea unguium, tinea corporis, and tinea faciei had a prevalence of 0.8%, 0.6%, and 0.5%, respectively. Tinea manuum had the least prevalence of 0.1%. Pityriasis versicolor had a prevalence of 4.4%. Microsporum audouinii was the leading organism isolated. The study shows that the prevalence of superficial fungal infection (SFI) among primary school children in Ile-Ife is high with tinea capitis as the commonest SFI. PMID:25574161
Yang, Fen; Braga, Marcella Nunes de Melo; Larsen, Martin Røssel
accumulation of signal molecules, including calcium, H2O2, NO, and sugars, in the resistant than in the susceptible cultivar in response to the infection. Additionally, 31 proteins and 5 phosphoproteins from the pathogen were identified, including metabolic proteins and signaling proteins such as GTP-binding...... proteins, 14-3-3 proteins, and calcium-binding proteins. Quantitative PCR analysis showed the expression of fungal signaling genes and genes encoding a superoxide dismutase and cell-wall degrading enzymes. These results indicate roles of signaling, antioxidative stress mechanisms, and nutrient acquisition...... resulting in a multiple-level activation of transcription and translation processes of defense responses. Our sensitive approaches and model provide a comprehensive (phospho)proteomics resource for studying signaling from the point of view of both host and pathogen during a plant-pathogen interaction....
Gelber, Jonathan T; Cope, Emily K; Goldberg, Andrew N; Pletcher, Steven D
Fungal hypersensitivity and fungal microbiome dysbiosis are possible etiologies of chronic rhinosinusitis. The sinus fungal microbiome is not well characterized; novel sinus-associated fungi, including Malassezia, have only recently been described. The goals for this study were to verify Malassezia as a dominant component of the sinus microbiome, to speciate sinus Malassezia, and to compare select fungal species in chronic rhinosinusitis (CRS) subtypes with known fungal association to chronic rhinosinusitis with polyps (CRSwNP) and healthy controls. Twenty-eight patients were enrolled and categorized as CRSwNP (n = 15), fungus ball (n = 3), allergic fungal rhinosinusitis (AFRS, n = 3), or healthy control (n = 7). Brush samples were taken from ethmoid or maxillary sinus mucosa and tested for DNA from 7 index fungi using quantitative polymerase chain reaction. Index fungal species were chosen based on existing data of the sinus fungal microbiome. Malassezia species were detected in 68% of patients, without variation among clinical phenotypes (p > 0.99). Malassezia restricta was more commonly detected than Malassezia globosa (p = 0.029). Presence of one Malassezia species predicted the presence of the other (p = 0.035). Aspergillus was identified in 2 of 3 of fungus ball patients (both A. fumigatus) and 2 of 3 AFRS patients (1 A. fumigatus and 1 A. flavus). Aspergillus was absent in control and CRSwNP patients (p Malassezia in healthy and diseased sinuses. Presence of Malassezia species in all groups suggests a commensal role for the fungus. Future work will determine whether Malassezia influences CRS pathogenesis. Aspergillus species were identified in fungal CRS subtypes despite negative surgical cultures, highlighting the importance of culture-independent technology. © 2016 ARS-AAOA, LLC.
In several insect systems, fungal entomopathogens synergize with neonicotinoid insecticides which results in accelerated host death. Using the Asian longhorned beetle, Anoplophora glabripennis (Motschulsky), an invasive woodborer inadvertently introduced into North America and Europe, we investigate...
Full Text Available Housaku Monogatari (HM is a plant activator prepared from a yeast cell wall extract. We examined the efficacy of HM application and observed that HM treatment increased the resistance of Arabidopsis thaliana and Brassica rapa leaves to bacterial and fungal infections. HM reduced the severity of bacterial leaf spot and anthracnose on A. thaliana and Brassica crop leaves with protective effects. In addition, gene expression analysis of A. thaliana plants after treatment with HM indicated increased expression of several plant defense-related genes. HM treatment appears to induce early activation of jasmonate/ethylene and late activation of salicylic acid (SA pathways. Analysis using signaling mutants revealed that HM required SA accumulation and SA signaling to facilitate resistance to the bacterial pathogen Pseudomonas syringae pv. maculicola and the fungal pathogen Colletotrichum higginsianum. In addition, HM-induced resistance conferred chitin-independent disease resistance to bacterial pathogens in A. thaliana. These results suggest that HM contains multiple microbe-associated molecular patterns that activate defense responses in plants. These findings suggest that the application of HM is a useful tool that may facilitate new disease control methods.
De León, Marina E; Vredenburg, Vance T; Piovia-Scott, Jonah
The pathogenic fungus Batrachochytrium dendrobatidis (Bd) has been associated with global amphibian declines, but it is often difficult to discern the relative importance of Bd as a causal agent in declines that have already occurred. Retrospective analyses of museum specimens have allowed researchers to associate the timing of Bd arrival with the timing of past amphibian declines. Cascades frogs (Rana cascadae) have experienced dramatic declines in northern California, but it is not clear whether the onset of these declines corresponds to the arrival of Bd. We used quantitative real-time PCR assays of samples collected from museum specimens to determine historical Bd prevalence in the northern California range of Cascades frogs. We detected Bd in 13 of 364 (3.5%) Cascades frog specimens collected between 1907 and 2003, with the first positive result from 1978. A Bayesian analysis suggested that Bd arrived in the region between 1973 and 1978, which corresponds well with the first observations of declines in the 1980s.
Nenoff, P; Ginter-Hanselmayer, G; Tietz, H-J
Onychomycosis describes a chronic fungal infection of the nails most frequently caused by dermatophytes, primarily Trichophyton rubrum. In addition, yeasts (e. g. Candida parapsilosis), more rarely molds (Scopulariopsis brevicaulis), play a role as causative agents of onychomycosis. However, in every case it has to be decided if these yeasts and molds are contaminants, or if they are growing secondarily on pathological altered nails. The point prevalence of onychomycosis in Germany is 12.4%, as demonstrated within the "Foot-Check-Study", which was a part of the European Achilles project. Although, onychomycosis is rarely diagnosed in children and teens, now an increase of fungal nail infections has been observed in childhood. More and more, diabetes mellitus becomes important as significant disposing factor both for tinea pedis and onychomycosis. By implication, the onychomycosis represents an independent and important predictor for development of diabetic foot syndrome and foot ulcer. When considering onychomycosis, a number of infectious and non-infectious nail changes must be excluded. While psoriasis of the nails does not represent a specific risk factor for onychomycosis, yeasts and molds are increasing isolated from patients with psoriatic nail involvement. In most cases this represents secondary growth of fungi on psoriatic nails. Recently, stigmatization and impairment of quality of life due to the onychomycosis has been proven.
%), Fusarium moniliforme (12.67%), Penicillium notatum (14.48%) and Rhizopus nigricans (24.70%) as the associated pathogens. The distribution, pathogenicity and spore germination kinetics were discussed and control measures proffered.
Van Agtmaal, M.; Straathof, A.L.; Termorshuizen, A.J.; Teurlincx, S.; Hundscheid, M.P.J.; Ruyters, S; Busschaert, P.; Lievens, Bart; De Boer, W.
Soil-borne pathogens cause great crop losses in agriculture. Because of their resilience in the soil, these pathogens persist in a population reservoir, causing future outbreaks of crop diseases. Management focus is usually on the most common pathogens occurring, but it is likely that a mixed
Agtmaal, van M.; Straathof, Angela; Termorshuizen, Aad; Teurlincx, Sven; Hundscheid, Maria; Ruyters, Stefan; Busschaert, Pieter; Lievens, Bart; Boer, de Wietse
Soil-borne pathogens cause great crop losses in agriculture. Because of their resilience in the soil, these pathogens persist in a population reservoir, causing future outbreaks of crop diseases. Management focus is usually on the most common pathogens occurring, but it is likely that a mixed
Julie Beckstead; Susan E. Meyer; Toby S. Ishizuka; Kelsey M. McEvoy; Craig E. Coleman
Generalist plant pathogens may have wide host ranges, but many exhibit varying degrees of host specialization, with multiple pathogen races that have narrower host ranges. These races are often genetically distinct, with each race causing highest disease incidence on its host of origin. We examined host specialization in the seed pathogen Pyrenophora...
Harkenrider, Mitch; Sharma, Rita; De Vleesschauwer, David; Tsao, Li; Zhang, Xuting; Chern, Mawsheng; Canlas, Patrick; Zuo, Shimin; Ronald, Pamela C.
Wall-associated kinases comprise a sub-family of receptor-like kinases that function in plant growth and stress responses. Previous studies have shown that the rice wall-associated kinase, OsWAK25, interacts with a diverse set of proteins associated with both biotic and abiotic stress responses. Here, we show that wounding and BTH treatments induce OsWAK25 transcript expression in rice. We generated OsWAK25 overexpression lines and show that these lines exhibit a lesion mimic phenotype and enhanced expression of rice NH1 (NPR1 homolog 1), OsPAL2, PBZ1 and PR10. Furthermore, these lines show resistance to the hemibiotrophic pathogens, Xanthomonas oryzae pv. oryzae (Xoo) and Magnaporthe oryzae, yet display increased susceptibility to necrotrophic fungal pathogens, Rhizoctonia solani and Cochliobolus miyabeanus. PMID:26795719
Varga, Zs; Fischl, G
Authors made mycological investigations on smooth brome (Bromus inermis Leyss.) cultivar 'K51'. During the vegetation period presence and dominance of fungal species were revealed and seed infection rates were tested in two winter season. Puccinia recondita, Puccinia coronata, Stagnospora bromi and Drechslera dictyoides were dominated on the leaves, but saprotrophic fungal genera (Alternaria, Epicoccum, Cladosporium, Pithomyces) were also identified. Considerable rate of seed infection were observed in both year. This is the first report on the presence of Pithomyces chartarum identified on leaves and seeds of smooth brome in Hungary.
Frandsen, Rasmus John Normand; Frandsen, Mette; Giese, Nanna Henriette
cloning without the need for subcloning. The cloning efficiency is not always as high as desired, but it still presents an efficient alternative to restriction enzyme and ligase-based cloning systems. The USER technology offers a higher four fragment cloning efficiency than In-Fusion, but depends...... on specific structures in the binary vector. The available fungal binary vectors adapted for the USER system are described and protocols are provided for vector design and construction. A general protocol for verification of the resulting gene replacement events in the recipient fungal cells is also given...
Cho, Yangrae; Ohm, Robin A. [US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA, 94598, USA; Grigoriev, Igor V. [US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA, 94598, USA; Srivastava, Akhil [Plant and Environmental Protection Sciences, University of Hawaii at Manoa, 3190 Maile Way, St John 317, Honolulu, HI, 96822, USA
Alternaria brassicicola is a successful saprophyte and necrotrophic plant pathogen. To identify molecular determinants of pathogenicity, we created non-pathogenic mutants of a transcription factor-encoding gene, AbPf2. The frequency and timing of germination and appressorium formation on host plants were similar between the non-pathogenic abpf2 mutants and wild-type A. brassicicola. The mutants were also similar in vitro to wild-type A. brassicicola in terms of vegetative growth, conidium production, and responses to a phytoalexin, reactive oxygen species and osmolites. The hyphae of the mutants grew slowly but did not cause disease symptoms on the surface of host plants. Transcripts of the AbPf2 gene increased exponentially soon after wild-type conidia contacted their host plants . A small amount of AbPf2 protein, as monitored using GFP fusions, was present in young, mature conidia. The protein level decreased during saprophytic growth, but increased and was located primarily in fungal nuclei during pathogenesis. Levels of the proteins and transcripts sharply decreased following colonization of host tissues beyond the initial infection site. When expression of the transcription factor was induced in the wild-type during early pathogenesis, 106 fungal genes were also induced in the wild-type but not in the abpf2 mutants. Notably, 33 of the 106 genes encoded secreted proteins, including eight putative effector proteins. Plants inoculated with abpf2 mutants expressed higher levels of genes associated with photosynthesis, the pentose phosphate pathway and primary metabolism, but lower levels of defense-related genes. Our results suggest that AbPf2 is an important regulator of pathogenesis, but does not affect other cellular processes in A. brassicicola.
Zihalirwa Kulimushi, Parent; Argüelles Arias, Anthony; Franzil, Laurent; Steels, Sébastien; Ongena, Marc
Most isolates belonging to the Bacillus amyloliquefaciens subsp. plantarum clade retain the potential to produce a vast array of structurally diverse antimicrobial compounds that largely contribute to their efficacy as biocontrol agents against numerous plant fungal pathogens. In that context, the role of cyclic lipopeptides (CLPs) has been well-documented but still little is known about the impact of interactions with other soil-inhabiting microbes on the expression of these molecules. In this work, we wanted to investigate the antagonistic activity developed by this bacterium against Rhizomucor variabilis, a pathogen isolated from diseased maize cobs in Democratic Republic of Congo. Our data show that fengycins are the major compounds involved in the inhibitory activity but also that production of this type of CLP is significantly upregulated when co-cultured with the fungus compared to pure cultures. B. amyloliquefaciens is thus able to perceive fungal molecules that are emitted and, as a response, up-regulates the biosynthesis of some specific components of its antimicrobial arsenal. PMID:28555132
Inositol is an essential nutrient with important structural and signaling functions in eukaryotes. Its role in microbial pathogenesis has been reported in fungi, protozoans, and eubacteria. In a recent article, Porollo et al. [mBio 5(6):e01834-14, 2014, doi:10.1128/mBio.01834-14] demonstrated the importance of inositol metabolism in the development and viability of Pneumocystis species--obligate fungal pathogens that remain unculturable in vitro. To understand their obligate nature, the authors used innovative comparative genomic approaches and discovered that Pneumocystis spp. are inositol auxotrophs due to the lack of inositol biosynthetic enzymes and that inositol insufficiency is a contributing factor preventing fungal growth in vitro. This work is in accord with other studies suggesting that inositol plays a conserved role in microbial pathogenesis. Inositol uptake and metabolism therefore may represent novel antimicrobial drug targets. Using comparative genomics to analyze metabolic pathways offers a powerful tool to gain new insights into nutrient utilization in microbes, especially obligate pathogens. Copyright © 2015 Xue.
Full Text Available Background: Cockroaches are the most prevalent domestic pests of a worldwide distribution. They were recognized as possible vectors of pathogenic bacteria, viruses, fungi and parasites in residential dwellings and hospital environments. The present study isolated and identified yeasts and filamentous fungi from digestive tract of American cockroaches, collected from three different residential regions of Iran.Methods: Seventy cockroaches were sampled using direct collection (hand catch, vacuum cleaner and sticky traps in Ahvaz, Iran in 2009–2010. Their medically important fungal microorganisms were isolated from digestive tract using standard mycological methods. Filamentous fungi were identified by macroscopic and microscopic examination. Yeasts were identified by API ID32C-32100 kit.Results: A high percentage of cockroaches (88.6% were detected to carry fungi of medical importance. Overall, 23 fungi species/genera were isolated from the American cockroaches' alimentary tract. The fungi isolated from cockroaches, from the residential regions were species of Aspergillus, Rhizopus, Penicillium, Mucorales, Alternaria, Cladosporium, Mycelia, Chrysosporium, Candida, Rhodotorula, Zygosaccharomyces, and Debaryomyces. Candida spp. (41.4%, Aspergillus spp. (37.1% and Rhodotorula spp (27.1% were the most common fungi recovered on cockroaches. Candida albicans and Candida glabrata were the commonest species of the genus Candida. In addition, Aspergillus niger and A. flavus were the most frequent species of the genus Aspergillus.Conclusion: American cockroaches may carry pathogenic fungi in the urban areas of Ahvaz.
Fungi in the ascomycete genus Colletotrichum are ranked by the plant pathology community as one of the ten most economically and scientifically important fungal phytopathogens. Major losses due to Colletotrichum are experienced in almost every crop worldwide, including nursery and landscape plants ...
Rambutan (Nephelium lappaceum Linn.) is a tropical fruit in Hawaii that has increased in value in the niche market of exotic fruits. The primary limitation to pre-harvest and post-harvest quality is the occurrence of fungal diseases of the fruit. A survey of rambutan disease was conducted in Hilo, H...
Different fungi have been associated with diseased inflorescences, leaves, and fruits of mango, rambutan and longan. During a fungal disease survey conducted between 2008 and 2013 at six orchards of rambutan and longan, and one orchard of mango in Puerto Rico, symptoms such as fruit rot, infloresc...
Hagen, F.; Ceresini, P.C.; Polacheck, I.; Ma, H.; van Nieuwerburgh, F.; Gabaldon, T.; Kagan, S.; Pursall, E.R.; Hoogveld, H.L.; van Iersel, L.J.; Klau, G.W.; Kelk, S.M.; Stougie, L.; Bartlett, K.H.; Voelz, K.; Pryszcz, L.P.; Castaneda, E.; Lazera, M.; Meyer, W.; Deforce, D.; Meis, J.F.G.M.; May, R.C.; Klaassen, C.H.W.; Boekhout, T.
Over the past two decades, several fungal outbreaks have occurred, including the high-profile 'Vancouver Island' and 'Pacific Northwest' outbreaks, caused by Cryptococcus gattii, which has affected hundreds of otherwise healthy humans and animals. Over the same time period, C. gattii was the cause
Hagen, F.; Ceresini, P.C.; Polacheck, I.; Ma, H.; Nieuwerburgh, F. van; Gabaldón, T.; Kagan, S.; Pursall, E.R.; Hoogveld, H.L.; Iersel, L.J. van; Klau, G.W.; Kelk, S.M.; Stougie, L.; Bartlett, K.H.; Voelz, K.; Pryszcz, L.P.; Castañeda, E.; Lazera, M.; Meyer, W.; Deforce, D.; Meis, J.F.G.M.; May, R.C.; Klaassen, C.H.; Boekhout, T.
Over the past two decades, several fungal outbreaks have occurred, including the high-profile 'Vancouver Island' and 'Pacific Northwest' outbreaks, caused by Cryptococcus gattii, which has affected hundreds of otherwise healthy humans and animals. Over the same time period, C. gattii was the cause
Michael E Colvin
Full Text Available Most pathogen detection tests are imperfect, with a sensitivity < 100%, thereby resulting in the potential for a false negative, where a pathogen is present but not detected. False negatives in a sample inflate the number of non-detections, negatively biasing estimates of pathogen prevalence. Histological examination of tissues as a diagnostic test can be advantageous as multiple pathogens can be examined and providing important information on associated pathological changes to the host. However, it is usually less sensitive than molecular or microbiological tests for specific pathogens. Our study objectives were to 1 develop a hierarchical occupancy model to examine pathogen prevalence in spring Chinook salmon Oncorhynchus tshawytscha and their distribution among host tissues 2 use the model to estimate pathogen-specific test sensitivities and infection rates, and 3 illustrate the effect of using replicate within host sampling on sample sizes required to detect a pathogen. We examined histological sections of replicate tissue samples from spring Chinook salmon O. tshawytscha collected after spawning for common pathogens seen in this population: Apophallus/echinostome metacercariae, Parvicapsula minibicornis, Nanophyetus salmincola/ metacercariae, and Renibacterium salmoninarum. A hierarchical occupancy model was developed to estimate pathogen and tissue-specific test sensitivities and unbiased estimation of host- and organ-level infection rates. Model estimated sensitivities and host- and organ-level infections rates varied among pathogens and model estimated infection rate was higher than prevalence unadjusted for test sensitivity, confirming that prevalence unadjusted for test sensitivity was negatively biased. The modeling approach provided an analytical approach for using hierarchically structured pathogen detection data from lower sensitivity diagnostic tests, such as histology, to obtain unbiased pathogen prevalence estimates with
Marshall, Andrew C; Kroker, Alice J; Murray, Lauren A M; Gronthos, Kahlia; Rajapaksha, Harinda; Wegener, Kate L; Bruning, John B
The fungal pathogen Aspergillus fumigatus has been implicated in a drastic increase in life-threatening infections over the past decade. However, compared to other microbial pathogens, little is known about the essential molecular processes of this organism. One such fundamental process is DNA replication. The protein responsible for ensuring processive DNA replication is PCNA (proliferating cell nuclear antigen, also known as the sliding clamp), which clamps the replicative polymerase to DNA. Here we present the first crystal structure of a sliding clamp from a pathogenic fungus (A. fumigatus), at 2.6Å. Surprisingly, the structure bears more similarity to the human sliding clamp than other available fungal sliding clamps. Reflecting this, fluorescence polarization experiments demonstrated that AfumPCNA interacts with the PCNA-interacting protein (PIP-box) motif of human p21 with an affinity (K d ) of 3.1 μm. Molecular dynamics simulations were carried out to better understand how AfumPCNA interacts with human p21. These simulations revealed that the PIP-box bound to AfuPCNA forms a secondary structure similar to that observed in the human complex, with a central 3 10 helix contacting the hydrophobic surface pocket of AfumPCNA as well as a β-strand that forms an antiparallel sheet with the AfumPCNA surface. Differences in the 3 10 helix interaction with PCNA, attributed to residue Thr131 of AfumPCNA, and a less stable β-strand formation, attributed to residues Gln123 and His125 of AfumPCNA, are likely causes of the over 10-fold lower affinity of the p21 PIP-box for AfumPCNA as compared to hPCNA. The atomic coordinates and structure factors for the Aspergillus fumigatus sliding clamp can be found in the RCSB Protein Data Bank (http://www.rcsb.org) under the accession code 5TUP. © 2017 Federation of European Biochemical Societies.
Fungi represent an ecologically diverse group of microorganisms that includes plant pathogenic species able to cause considerable yield loses in crop production systems worldwide. In order to establish compatible interactions with their hosts, pathogenic fungi rely on the secretion of molecules of d...
The forest pathogen Armillaria mellea s.s. (Basidiomycota, Physalacriaceae) is among the most significant forest pathogens causing root rot in northern temperate forest trees worldwide. Phylogenetic reconstructions for A. mellea show distinct European, Asian and North American lineages. The North Am...
Shetty, N.P.; Mehrabi, R.; Lütken, H.; Haldrup, A.; Kema, G.H.J.
Hydrogen peroxide (H2O2) is reported to inhibit biotrophic but benefit necrotrophic pathogens. Infection by necrotrophs can result in a massive accumulation of H2O2 in hosts. Little is known of how pathogens with both growth types are affected (hemibiotrophs). The hemibiotroph, Septoria tritici,
Jonge, de R.; Bolton, M.D.; Thomma, B.P.H.J.
Research on effectors secreted by pathogens during host attack has dominated the field of molecular plant–microbe interactions over recent years. Functional analysis of type III secreted effectors injected by pathogenic bacteria into host cells has significantly advanced the field and demonstrated
Conti, Heather R.; Gaffen, Sarah L.
IL-17 (IL-17A) has emerged as a key mediator of protection against extracellular microbes, but this cytokine also drives pathology in various autoimmune diseases. Overwhelming data in both humans and mice reveal a clear and surprisingly specific role for IL-17 in protection against the fungus Candida albicans, a commensal of the human oral cavity, gastrointestinal tract and reproductive mucosa. The IL-17 pathway regulates antifungal immunity through upregulation of pro-inflammatory cytokines including IL-6, neutrophil-recruiting chemokines such as CXCL1 and CXCL5 and antimicrobial peptides such as the defensins, which act in concert to limit fungal overgrowth. This review will focus on diseases caused by C. albicans, the role of IL-17-mediated immunity in candidiasis, and the implications for clinical therapies for both autoimmune conditions and fungal infections. PMID:26188072
Cordero-Bueso, Gustavo; Mangieri, Nicola; Maghradze, David; Foschino, Roberto; Valdetara, Federica; Cantoral, Jesús M.; Vigentini, Ileana
The increasing level of hazardous residues in the environment and food chains has led the European Union to restrict the use of chemical fungicides. Thus, exploiting new natural antagonistic microorganisms against fungal diseases could serve the agricultural production to reduce pre- and post-harvest losses, to boost safer practices for workers and to protect the consumers' health. The main aim of this work was to evaluate the antagonistic potential of epiphytic yeasts against Botrytis cinere...
Zhang, Jie-Chi; Kong, Xiang-Hui; Zhang, Pi-Qi; Liu, Jia-Ning; Ma, Yin-Peng; Dai, Xiao-Dong; Han, Zeng-Hua; Ma, Qing-Fang; Wang, Xiao-Yong; Yu, Li-Ping
Auricularia auricula-judae is an edible and medicinal fungus ranking fourth in production among the edible fungi cultivated worldwide. White villous disease is rampant in Northeast China; it infects the fruiting bodies of A. auricula-judae by forming a white mycelial layer on its ventral side. The disease not only causes an unacceptable morphological appearance and a poor-quality product, but it also significantly reduces the yield. In this study, based on fungal morphology, ribosomal DNA internal transcribed spacer sequences, identification of species-specific primers, and the pathogenicity of the mycelia and spores, 2 fungal pathogens were isolated and identified as Fusarium equiseti and F. sporotrichioides.
Subodh K Srivastava
Full Text Available Fusarium virguliforme causes sudden death syndrome (SDS of soybean, a disease of serious concern throughout most of the soybean producing regions of the world. Despite the global importance, little is known about the pathogenesis mechanisms of F. virguliforme. Thus, we applied Next-Generation DNA Sequencing to reveal the draft F. virguliforme genome sequence and identified putative pathogenicity genes to facilitate discovering the mechanisms used by the pathogen to cause this disease.We have generated the draft genome sequence of F. virguliforme by conducting whole-genome shotgun sequencing on a 454 GS-FLX Titanium sequencer. Initially, single-end reads of a 400-bp shotgun library were assembled using the PCAP program. Paired end sequences from 3 and 20 Kb DNA fragments and approximately 100 Kb inserts of 1,400 BAC clones were used to generate the assembled genome. The assembled genome sequence was 51 Mb. The N50 scaffold number was 11 with an N50 Scaffold length of 1,263 Kb. The AUGUSTUS gene prediction program predicted 14,845 putative genes, which were annotated with Pfam and GO databases. Gene distributions were uniform in all but one of the major scaffolds. Phylogenic analyses revealed that F. virguliforme was closely related to the pea pathogen, Nectria haematococca. Of the 14,845 F. virguliforme genes, 11,043 were conserved among five Fusarium species: F. virguliforme, F. graminearum, F. verticillioides, F. oxysporum and N. haematococca; and 1,332 F. virguliforme-specific genes, which may include pathogenicity genes. Additionally, searches for candidate F. virguliforme pathogenicity genes using gene sequences of the pathogen-host interaction database identified 358 genes.The F. virguliforme genome sequence and putative pathogenicity genes presented here will facilitate identification of pathogenicity mechanisms involved in SDS development. Together, these resources will expedite our efforts towards discovering pathogenicity mechanisms in
Ingle, Robert A; Stoker, Claire; Stone, Wendy; Adams, Nicolette; Smith, Rob; Grant, Murray; Carré, Isabelle; Roden, Laura C; Denby, Katherine J
The circadian clock, an internal time-keeping mechanism, allows plants to anticipate regular changes in the environment, such as light and dark, and biotic challenges such as pathogens and herbivores. Here, we demonstrate that the plant circadian clock influences susceptibility to the necrotrophic fungal pathogen, Botrytis cinerea. Arabidopsis plants show differential susceptibility to B. cinerea depending on the time of day of inoculation. Decreased susceptibility after inoculation at dawn compared with night persists under constant light conditions and is disrupted in dysfunctional clock mutants, demonstrating the role of the plant clock in driving time-of-day susceptibility to B. cinerea. The decreased susceptibility to B. cinerea following inoculation at subjective dawn was associated with faster transcriptional reprogramming of the defence response with gating of infection-responsive genes apparent. Direct target genes of core clock regulators were enriched among the transcription factors that responded more rapidly to infection at subjective dawn than subjective night, suggesting an influence of the clock on the defence-signalling network. In addition, jasmonate signalling plays a crucial role in the rhythmic susceptibility of Arabidopsis to B. cinerea with the enhanced susceptibility to this pathogen at subjective night lost in a jaz6 mutant. © 2015 The Authors The Plant Journal published by Society for Experimental Biology and John Wiley & Sons Ltd.
Olson, Ake; Aerts, Andrea; Asiegbu, Fred; Belbahri, Lassaad; Bouzid, Ourdia; Broberg, Anders; Canback, Bjorn; Coutinho, Pedro M.; Cullen, Dan; Dalman, Kerstin; Deflorio, Giuliana; van Diepen, Linda T. A.; Dunand, Christophe; Duplessis, Sebastien; Durling, Mikael; Gonthier, Paolo; Grimwood, Jane; Fossdal, Carl Gunnar; Hansson, David; Henrissat, Bernard; Hietala, Ari; Himmelstrand, Kajsa; Hoffmeister, Dirk; Hogberg, Nils; James, Timothy Y.; Karlsson, Magnus; Kohler, Annegret; Lucas, Susan; Lunden, Karl; Morin, Emmanuelle; Murat, Claude; Park, Jongsun; Raffaello, Tommaso; Rouze, Pierre; Salamov, Asaf; Schmutz, Jeremy; Solheim, Halvor; Stahlberg, Jerry; Velez, Heriberto; de Vries, Ronald P.; Wiebenga, Ad; Woodward, Steve; Yakovlev, Igor; Garbelotto, Matteo; Martin, Francis; Grigoriev, Igor V.; Stenlid, Jan
Parasitism and saprotrophic wood decay are two fungal strategies fundamental for succession and nutrient cycling in forest ecosystems. An opportunity to assess the trade-off between these strategies is provided by the forest pathogen and wood decayer Heterobasidion annosum sensu lato. We report the annotated genome sequence and transcript profiling, as well as the quantitative trait loci mapping, of one member of the species complex: H. irregulare. Quantitative trait loci critical for pathogenicity, and rich in transposable elements, orphan and secreted genes, were identified. A wide range of cellulose-degrading enzymes are expressed during wood decay. By contrast, pathogenic interaction between H. irregulare and pine engages fewer carbohydrate-active enzymes, but involves an increase in pectinolytic enzymes, transcription modules for oxidative stress and secondary metabolite production. Our results show a trade-off in terms of constrained carbohydrate decomposition and membrane transport capacity during interaction with living hosts. Our findings establish that saprotrophic wood decay and necrotrophic parasitism involve two distinct, yet overlapping, processes.
PDA). The consistently isolated fungi from the fruits and seeds were identified as Penicillium digitatum, Aspergillus flavus and Aspergillus niger while a specie of Verticillium was isolated from the leaves and stems. Pathogenicity tests on fresh ...
Blatzer, Michael; Latgé, Jean-Paul
In contrast to obligate pathogens opportunistic pathogens such as Aspergillus fumigatus do not need a specific host to propagate or survive. However several characteristics of the saprophytic life-style and the selective pressure encountered in the primary ecological niche contribute to the virulence of A. fumigatus. All fungi depend on metals for growth and proliferation, like iron, copper, zinc, manganese or calcium. In the recent past several studies explored the manifold impact of metals modulating virulence of pathogens. Components which might be scarce in the natural environment but also in the host due to nutritional immunity. This review recapitulates molecular constituents of metal ion uptake systems in A. fumigatus, their regulation and their significance at the host-pathogen battlefield. Copyright © 2017 Elsevier Ltd. All rights reserved.
Navaud, Olivier; Barbacci, Adelin; Taylor, Andrew; Clarkson, John P; Raffaele, Sylvain
The range of hosts that a parasite can infect in nature is a trait determined by its own evolutionary history and that of its potential hosts. However, knowledge on host range diversity and evolution at the family level is often lacking. Here, we investigate host range variation and diversification trends within the Sclerotiniaceae, a family of Ascomycete fungi. Using a phylogenetic framework, we associate diversification rates, the frequency of host jump events and host range variation during the evolution of this family. Variations in diversification rate during the evolution of the Sclerotiniaceae define three major macro-evolutionary regimes with contrasted proportions of species infecting a broad range of hosts. Host-parasite cophylogenetic analyses pointed towards parasite radiation on distant hosts long after host speciation (host jump or duplication events) as the dominant mode of association with plants in the Sclerotiniaceae. The intermediate macro-evolutionary regime showed a low diversification rate, high frequency of duplication events and the highest proportion of broad host range species. Our findings suggest that the emergence of broad host range fungal pathogens results largely from host jumps, as previously reported for oomycete parasites, probably combined with low speciation rates. These results have important implications for our understanding of fungal parasites evolution and are of particular relevance for the durable management of disease epidemics. © 2018 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.
Vollmer, Jeanette Hyldal
Plant diseases caused by fungi are major potential threats to yield in both organic and conventional cereal production, and generally several species of pathogenic fungi are found together on the same plants in the field. This PhD thesis concludes, thatinteraction between different foliar fungal...... species may influence total disease levels and often via negative effects. This implies that less disease is observed where several diseases occur together, relative to where they occur individually. Suchinteraction effects have often been ignored in the past, as plant diseases are traditionally studied...... as independent events. The thesis provides an important review of available literature, considering the theoretical background for analyzing foliardisease interactions as well as previously published data studies. Difficulties in istinguishing different types of competition are emphasized. The thesis considers...
Adam, Mohamed; Heuer, Holger; Hallmann, Johannes
The potential of bacterial antagonists of fungal pathogens to control the root-knot nematode Meloidogyne incognita was investigated under greenhouse conditions. Treatment of tomato seeds with several strains significantly reduced the numbers of galls and egg masses compared with the untreated control. Best performed Bacillus subtilis isolates Sb4-23, Mc5-Re2, and Mc2-Re2, which were further studied for their mode of action with regard to direct effects by bacterial metabolites or repellents, and plant mediated effects. Drenching of soil with culture supernatants significantly reduced the number of egg masses produced by M. incognita on tomato by up to 62% compared to the control without culture supernatant. Repellence of juveniles by the antagonists was shown in a linked twin-pot set-up, where a majority of juveniles penetrated roots on the side without inoculated antagonists. All tested biocontrol strains induced systemic resistance against M. incognita in tomato, as revealed in a split-root system where the bacteria and the nematodes were inoculated at spatially separated roots of the same plant. This reduced the production of egg masses by up to 51%, while inoculation of bacteria and nematodes in the same pot had only a minor additive effect on suppression of M. incognita compared to induced systemic resistance alone. Therefore, the plant mediated effect was the major reason for antagonism rather than direct mechanisms. In conclusion, the bacteria known for their antagonistic potential against fungal pathogens also suppressed M. incognita. Such "multi-purpose" bacteria might provide new options for control strategies, especially with respect to nematode-fungus disease complexes that cause synergistic yield losses.
Badet, Thomas; Peyraud, Rémi; Raffaele, Sylvain
Fungal plant pathogens produce secreted proteins adapted to function outside fungal cells to facilitate colonization of their hosts. In many cases such as for fungi from the Sclerotiniaceae family the repertoire and function of secreted proteins remains elusive. In the Sclerotiniaceae, whereas Sclerotinia sclerotiorum and Botrytis cinerea are cosmopolitan broad host-range plant pathogens, Sclerotinia borealis has a psychrophilic lifestyle with a low optimal growth temperature, a narrow host range and geographic distribution. To spread successfully, S. borealis must synthesize proteins adapted to function in its specific environment. The search for signatures of adaptation to S. borealis lifestyle may therefore help revealing proteins critical for colonization of the environment by Sclerotiniaceae fungi. Here, we analyzed amino acids usage and intrinsic protein disorder in alignments of groups of orthologous proteins from the three Sclerotiniaceae species. We found that enrichment in Thr, depletion in Glu and Lys, and low disorder frequency in hot loops are significantly associated with S. borealis proteins. We designed an index to report bias in these properties and found that high index proteins were enriched among secreted proteins in the three Sclerotiniaceae fungi. High index proteins were also enriched in function associated with plant colonization in S. borealis, and in in planta-induced genes in S. sclerotiorum. We highlight a novel putative antifreeze protein and a novel putative lytic polysaccharide monooxygenase identified through our pipeline as candidate proteins involved in colonization of the environment. Our findings suggest that similar protein signatures associate with S. borealis lifestyle and with secretion in the Sclerotiniaceae. These signatures may be useful for identifying proteins of interest as targets for the management of plant diseases.
Full Text Available Fungal plant pathogens produce secreted proteins adapted to function outside fungal cells to facilitate colonization of their hosts. In many cases such as for fungi from the Sclerotiniaceae family the repertoire and function of secreted proteins remains elusive. In the Sclerotiniaceae, whereas Sclerotinia sclerotiorum and Botrytis cinerea are cosmopolitan broad host-range plant pathogens, Sclerotinia borealis has a psychrophilic lifestyle with a low optimal growth temperature, a narrow host range and geographic distribution. To spread successfully, S. borealis must synthesize proteins adapted to function in its specific environment. The search for signatures of adaptation to S. borealis lifestyle may therefore help revealing proteins critical for colonization of the environment by Sclerotiniaceae fungi. Here, we analyzed amino acids usage and intrinsic protein disorder in alignments of groups of orthologous proteins from the three Sclerotiniaceae species. We found that enrichment in Thr, depletion in Glu and Lys, and low disorder frequency in hot loops are significantly associated with S. borealis proteins. We designed an index to report bias in these properties and found that high index proteins were enriched among secreted proteins in the three Sclerotiniaceae fungi. High index proteins were also enriched in function associated with plant colonization in S. borealis, and in in planta-induced genes in S. sclerotiorum. We highlight a novel putative antifreeze protein and a novel putative lytic polysaccharide monooxygenase identified through our pipeline as candidate proteins involved in colonization of the environment. Our findings suggest that similar protein signatures associate with S. borealis lifestyle and with secretion in the Sclerotiniaceae. These signatures may be useful for identifying proteins of interest as targets for the management of plant diseases.
Novohradská, Silvia; Ferling, Iuliia; Hillmann, Falk
Infections with filamentous fungi are common to all animals, but attention is rising especially due to the increasing incidence and high mortality rates observed in immunocompromised human individuals. Here, Aspergillus fumigatus and other members of its genus are the leading causative agents. Attributes like their saprophytic life-style in various ecological niches coupled with nutritional flexibility and a broad host range have fostered the hypothesis that environmental predators could have been the actual target for some of their virulence determinants. In this mini review, we have merged the recent findings focused on the potential dual-use of fungal defense strategies against innate immune cells and soil amoebae as natural phagocytes. Well-established virulence attributes like the melanized surface of fungal conidia or their capacity to produce toxic secondary metabolites have also been found to be protective against the model amoeba Dictyostelium discoideum . Some of the recent advances during interaction studies with human cells have further promoted the adaptation of other amoeba infection models, including the wide-spread generalist Acanthamoeba castellanii , or less prominent representatives like Vermamoeba vermiformis . We further highlight prospects and limits of these natural phagocyte models with regard to the infection biology of filamentous fungi and in comparison to the phagocytes of the innate immune system.
Full Text Available Infections with filamentous fungi are common to all animals, but attention is rising especially due to the increasing incidence and high mortality rates observed in immunocompromised human individuals. Here, Aspergillus fumigatus and other members of its genus are the leading causative agents. Attributes like their saprophytic life-style in various ecological niches coupled with nutritional flexibility and a broad host range have fostered the hypothesis that environmental predators could have been the actual target for some of their virulence determinants. In this mini review, we have merged the recent findings focused on the potential dual-use of fungal defense strategies against innate immune cells and soil amoebae as natural phagocytes. Well-established virulence attributes like the melanized surface of fungal conidia or their capacity to produce toxic secondary metabolites have also been found to be protective against the model amoeba Dictyostelium discoideum. Some of the recent advances during interaction studies with human cells have further promoted the adaptation of other amoeba infection models, including the wide-spread generalist Acanthamoeba castellanii, or less prominent representatives like Vermamoeba vermiformis. We further highlight prospects and limits of these natural phagocyte models with regard to the infection biology of filamentous fungi and in comparison to the phagocytes of the innate immune system.
Lavan, R; Knesl, O
To determine the prevalence of nine canine infectious respiratory disease (CIRD) pathogens in asymptomatic dogs presented at animal shelters across the United States. Ocular and oronasal swabs from asymptomatic dogs (n = 503) were tested using qPCR assay for Bordetella bronchiseptica, canine adenovirus type 2 (CAV-2), canine distemper virus (CDV), canine herpesvirus type 1 (CHV), canine influenza virus (CIV), canine parainfluenza virus (CPIV), canine respiratory coronavirus (CRCoV), Mycoplasma cynos and Streptococcus equi subsp zooepidemicus. A total of 240 (47.7%) asymptomatic dogs were PCR-positive for at least one CIRD pathogen. Prevalence of two-, three-, four-, and five-pathogen cases was 12.7, 3.8, 1.8, and 0.4%, respectively. Mycoplasma cynos (29.2%), B. bronchiseptica (19.5%), CAV-2 (12.5%), CDV (7.4%) and CPIV (3.2%) were the most commonly detected pathogens. The prevalence of traditional and newly emerging pathogens associated with CIRD is poorly defined in clinically healthy dogs. This study determined that a high percentage of asymptomatic shelter dogs harbor CIRD pathogens, including the newly emerging pathogen M. cynos and the historically prevalent pathogen B. bronchiseptica. © 2015 British Small Animal Veterinary Association.
scapularis-Pathogen prevalence-Rickettsia-Rickettsia amblyommii. Introduction TICK-BORNE ILLNESSES (TBis) are zoonoses involving pathogens...white- tailed deer, and emergence of Amblyomma americanum- associated zoonoses in the United States. CTMI 2007; 315: 289-324. Papin, JF, Vahrson, W
de Sain, Mara; Rep, Martijn
A limited number of fungi can cause wilting disease in plants through colonization of the vascular system, the most well-known being Verticillium dahliae and Fusarium oxysporum. Like all pathogenic microorganisms, vascular wilt fungi secrete proteins during host colonization. Whole-genome sequencing and proteomics screens have identified many of these proteins, including small, usually cysteine-rich proteins, necrosis-inducing proteins and enzymes. Gene deletion experiments have provided evidence that some of these proteins are required for pathogenicity, while the role of other secreted proteins remains enigmatic. On the other hand, the plant immune system can recognize some secreted proteins or their actions, resulting in disease resistance. We give an overview of proteins currently known to be secreted by vascular wilt fungi and discuss their role in pathogenicity and plant immunity.
Jensen, Annette Bruun; Welker, Dennis L.; Kryger, Per
The pathogenic fungus Ascosphaera apis is ubiquitous in honey bee populations. We used the draft genome assembly of this pathogen to search for polymorphic intergenic loci that could be used to differentiate haplotypes. Primers were developed for five such loci, and the species specificities were...... verified using DNA from nine closely related species. The sequence variation was compared among 12 A. apis isolates at each of these loci, and two additional loci, the internal transcribed spacer of the ribosomal RNA (ITS) and a variable part of the elongation factor 1α (Ef1α). The degree of variation...... was then compared among the different loci, and three were found to have the greatest detection power for identifying A. apis haplotypes. The described loci can help to resolve strain differences and population genetic structures, to elucidate host–pathogen interaction and to test evolutionary hypotheses...
Andleeb, Saiqa; Ejaz, Mubashir; Awan, Uzma Azeem; Ali, Shaukat; Kiyani, Ayesha; Shafique, Irsa; Zafar, Atiya
Earthworms are macro invertebrate and have been widely used as therapeutic drugs for thousands of years. In the current research, experiments viz., the antibacterial, antifungal and antioxidant activity of mucus and solvent extracts of Eisenia foetida were conducted to investigate for the first time in Pakistan against human infectious pathogens. Antimicrobial activity of E. foetida against human pathogens underwent investigation through an agar disc diffusion method while an ABTS(•+) free radical scavenging method assessed the antioxidant activity. The percentage of bacterial and fungal growth was analyzed statistically with One-Way Analysis of Variance (ANOVA). Results showed that the mucus IV of E. foetida produced a strong potent antibacterial and antifungal activity. Pseudomonas aeruginosa exhibited the highest inhibition zone (33.67±1.53 mm), followed by Klebsiella pneumonia (30.33±1.53mm), Penicillium notatum (30±0.051), Escherichia coli (29±1 mm), Candida albicans (28.33±0.54 mm), Staphylococcus aureus (27±1mm), Serratia marcescens (25.33±0.58 mm), Aspergillus flavus (25.33±0.58 mm), Staphylococcus epidermidis (24.33±0.58 mm), Streptococcus pyogenes (21.67±1.53 mm), and Aspergillus niger (20.67±0.53 mm). Mucus IV of E. foetida also showed the highest antioxidant activity (99%). The results clearly indicate that the mucus and solvent extracts contain effective antimicrobial properties and bioactive compounds to inhibit the growth of infectious pathogens. We conclude that mucus extracts of earthworm have significant level of antimicrobial and antioxidant activities and in future could be potentially used against various infectious pathogens.
We sequenced and compared the genomes of Dothideomycete fungal plant pathogens Cladosporium fulvum and Dothistroma septosporum that are related phylogenetically, but have different lifestyles and infect different hosts. C. fulvum is a biotroph that infects tomato, while D. septosporum is a hemibiotr...
Gramaje, D.; Leon, M.; Santana, M.; Crous, P.W.; Armengol, J.
Cadophora luteo-olivacea is a lesser-known fungal trunk pathogen of grapevine which has been recently isolated from vines showing decline symptoms in grape growing regions worldwide. In this study, 80 C. luteo-olivacea isolates (65 from Spain and 15 from South Africa) were studied.
Gramaje, David; León, Maela; Santana, Marcela; Crous, Pedro W; Armengol, Josep
Cadophora luteo-olivacea is a lesser-known fungal trunk pathogen of grapevine which has been recently isolated from vines showing decline symptoms in grape growing regions worldwide. In this study, 80 C. luteo-olivacea isolates (65 from Spain and 15 from South Africa) were studied.
Full Text Available Continuous rain and an abnormally wet climate during harvest can easily lead to soybean plants being damaged by field mold (FM, which can reduce seed yield and quality. However, to date, the underlying pathogen and its resistance mechanism have remained unclear. The objective of the present study was to investigate the fungal diversity of various soybean varieties and to identify and confirm the FM pathogenic fungi. A total of 62,382 fungal ITS1 sequences clustered into 164 operational taxonomic units (OTUs with 97% sequence similarity; 69 taxa were recovered from the samples by internal transcribed spacer (ITS region sequencing. The fungal community compositions differed among the tested soybeans, with 42 OTUs being amplified from all varieties. The quadratic relationships between fungal diversity and organ-specific mildew indexes were analyzed, confirming that mildew on soybean pods can mitigate FM damage to the seeds. In addition, four potentially pathogenic fungi were isolated from FM-damaged soybean fruits; morphological and molecular identification confirmed these fungi as Aspergillus flavus, A. niger, Fusarium moniliforme, and Penicillium chrysogenum. Further re-inoculation experiments demonstrated that F. moniliforme is dominant among these FM pathogenic fungi. These results lay the foundation for future studies on mitigating or preventing FM damage to soybean.
de Sain, M.; Rep, M.
A limited number of fungi can cause wilting disease in plants through colonization of the vascular system, the most well-known being Verticillium dahliae and Fusarium oxysporum. Like all pathogenic microorganisms, vascular wilt fungi secrete proteins during host colonization. Whole-genome sequencing
Cécile Robin; Amira Mougou-Hamdane; Jean-Marc Gion; Antoine Kremer; Marie-Laure. Desprez-Loustau
Powdery mildew, caused by Erysiphe alphitoides (Ascomycete), is the most frequent disease of oaks, which are also known to be host plants for Phytophthora cinnamomi (Oomycete), the causal agent of ink disease. Components of genetic resistance to these two pathogens, infecting either leaves or root and collar, were...
Jackson, A.P.; Gamble, J.A.; Yeomans, T.; Moran, G.P.; Saunders, D.; Harris, D.; Aslett, M.; Barrell, J.F.; Butler, G.; Citiulo, F.; Coleman, D.C.; de Groot, P.W.J.; Goodwin, T.J.; Quail, M.A.; McQuillan, J.; Munro, C.A.; Pain, A.; Poulter, R.T.; Rajandream, M-A.; Renauld, H.; Spiering, M.J.; Tivey, A.; Gow, N.A.R.; Barrell, B.; Sullivan, D.J.; Berriman, M.
Candida dubliniensis is the closest known relative of Candida albicans, the most pathogenic yeast species in humans. However, despite both species sharing many phenotypic characteristics, including the ability to form true hyphae, C. dubliniensis is a significantly less virulent and less versatile
Full Text Available Matrix metalloproteinases (MMPs are evolutionarily conserved and multifunctional effector molecules playing pivotal roles in development and homeostasis. In this study we explored the involvement of the five Arabidopsis thaliana At-MMPs in plant defence against microbial pathogens. Expression of At2-MMP was most responsive to inoculation with fungi and a bacterial pathogen followed by At3-MMP and At5-MMP, while At1-MMP and At4-MMP were non-responsive to these biotic stresses. Loss-of-function mutants for all tested At-MMPs displayed increased susceptibility to the necrotrophic fungus Botrytis cinerea and double mutant at2,3-mmp and triple mutant at2,3,5-mmp plants developed even stronger symptoms. Consistent with this, transgenic Arabidopsis plants that expressed At2-MMP constitutively under the Cauliflower mosaic virus 35S promoter showed enhanced resistance to the necrotrophic pathogen. Similarly, resistance to the biotrophic Arabidopsis powdery mildew fungus Golovinomyces orontii was also compromised particularly in the at2,3-mmp / at2,3,5-mmp multiplex mutants, and increased in At2-MMP overexpressor plants. The degree of disease resistance of at-mmp mutants and At2-MMP overexpressor plants also correlated positively with the degree of MAMP-triggered callose deposition in response to the bacterial flagellin peptide flg22, suggesting that matrix metalloproteinases contribute to pattern-triggered immunity (PTI in interactions of Arabidopsis with necrotrophic and biotrophic pathogens.
Baarlen, van P.; Staats, M.; Kan, van J.A.L.
The genus Botrytis contains necrotrophic plant pathogens that have a wide host range (B. cinerea) or are specialized on a single host species, e.g. B. elliptica on lily. In this study, it was found that B. elliptica-induced cell death of lily displays hallmark features of animal programmed cell
The honey fungus Armillaria mellea is a destructive soil-borne pathogen that affects over 300 plant species, and is of increasing interest due to its ability to decompose lignin. Here we report the transformation of this fungus. A range of techniques was evaluated, and Agrobacterium-mediated trans...
Jackson, Andrew P
Candida dubliniensis is the closest known relative of Candida albicans, the most pathogenic yeast species in humans. However, despite both species sharing many phenotypic characteristics, including the ability to form true hyphae, C. dubliniensis is a significantly less virulent and less versatile pathogen. Therefore, to identify C. albicans-specific genes that may be responsible for an increased capacity to cause disease, we have sequenced the C. dubliniensis genome and compared it with the known C. albicans genome sequence. Although the two genome sequences are highly similar and synteny is conserved throughout, 168 species-specific genes are identified, including some encoding known hyphal-specific virulence factors, such as the aspartyl proteinases Sap4 and Sap5 and the proposed invasin Als3. Among the 115 pseudogenes confirmed in C. dubliniensis are orthologs of several filamentous growth regulator (FGR) genes that also have suspected roles in pathogenesis. However, the principal differences in genomic repertoire concern expansion of the TLO gene family of putative transcription factors and the IFA family of putative transmembrane proteins in C. albicans, which represent novel candidate virulence-associated factors. The results suggest that the recent evolutionary histories of C. albicans and C. dubliniensis are quite different. While gene families instrumental in pathogenesis have been elaborated in C. albicans, C. dubliniensis has lost genomic capacity and key pathogenic functions. This could explain why C. albicans is a more potent pathogen in humans than C. dubliniensis.
Full Text Available Fungal diseases kill more than 1.5 million and affect over a billion people. However, they are still a neglected topic by public health authorities even though most deaths from fungal diseases are avoidable. Serious fungal infections occur as a consequence of other health problems including asthma, AIDS, cancer, organ transplantation and corticosteroid therapies. Early accurate diagnosis allows prompt antifungal therapy; however this is often delayed or unavailable leading to death, serious chronic illness or blindness. Recent global estimates have found 3,000,000 cases of chronic pulmonary aspergillosis, ~223,100 cases of cryptococcal meningitis complicating HIV/AIDS, ~700,000 cases of invasive candidiasis, ~500,000 cases of Pneumocystis jirovecii pneumonia, ~250,000 cases of invasive aspergillosis, ~100,000 cases of disseminated histoplasmosis, over 10,000,000 cases of fungal asthma and ~1,000,000 cases of fungal keratitis occur annually. Since 2013, the Leading International Fungal Education (LIFE portal has facilitated the estimation of the burden of serious fungal infections country by country for over 5.7 billion people (>80% of the world’s population. These studies have shown differences in the global burden between countries, within regions of the same country and between at risk populations. Here we interrogate the accuracy of these fungal infection burden estimates in the 43 published papers within the LIFE initiative.
Smith, Phil H; Howie, John A; Worland, Anthony J; Stratford, Rebecca; Boyd, Lesley A
Two mutants were isolated in wheat that showed enhanced resistance towards Puccinia striiformis f. sp. tritici, the fungal causal agent of yellow rust. The altered phenotype of I3-48 is due to a minimum of two mutation events, each showing a partial, additive effect, with one mutation segregating with a deletion on the long arm of chromosome 4D. In the case of I3-54, the enhanced resistance is due to a single, dominant mutation. In both mutants, the expression of the enhanced resistance is growth-stage specific. With I3-54, the full resistance phenotype is apparent from the third seedling leaf onwards, while with I3-48, a full resistance phenotype is only seen on the tenth and subsequent leaves. In addition to the enhanced resistance towards yellow rust, I3-48 also shows enhanced resistance towards brown rust, and I3-54 shows enhanced resistance to powdery mildew.
Full Text Available Abstract Background The use of newer azoles as prophylaxis in hematological patients undergoing stem cell transplantation or immunosuppressive chemotherapy has been shown to decrease the risk of developing invasive fungal disease (IFD. However, the cost-effectiveness of such a strategy is dependent on the local epidemiology of IFD. We conducted an audit of hematological patients with IFD in our institution in order to derive the prevalence and types of IFD that occur locally. Findings We conducted a retrospective chart review of all hematological patients who developed possible, probable or definite IFD according to EORTC/MSG criteria in the period from Oct 2007 to Apr 2010. The prevalence of IFD was determined via correlation with institutional database records of all hematological patients treated at our institution over the same time period. There were 39 cases of IFD diagnosed during the study period, with 8 (20.5% possible, 19 (48.7% probable and 12 (30.8% definite cases of IFD. Aspergillus spp. accounted for 83.9% of all probable and definite infections. There was 1 case each of Rhinocladelia spp., Coprinopsis cinerea, Exserohilum spp. sinusitis and Rhizopus spp. sinusitis. IFD occurred in 12 of 124 (9.7% AML and 4 of 103 (3.9% ALL patients treated at our institution respectively. There were 10 (16.1% infections among 62 allogeneic HSCT recipients, six of whom were having concurrent graft-versus-host disease (GVHD. Five other cases occurred after allogeneic HSCT failure, following salvage chemotherapy for disease relapse. The prevalence of IFD during induction chemotherapy was 8.9% (11 of 124 cases for AML and 1.0% (1 of 103 cases for ALL. Fluconazole prophylaxis had been provided for 28 out of the 39 (71.8% cases, while 4 (10.3% were on itraconazole prophylaxis. The in-hospital mortality was 28.2% (11 of 39 cases, of which 5 (12.8% deaths were attributed to IFD. Conclusions The burden of IFD is high in our institution, especially in
Ernesto Moya-Elizondo; Nolberto Arismendi; María Paz Castro; Herman Doussoulin
Crown rot pathogens are associated with higher losses for wheat crop farmers, but information about the distribution and prevalence of these pathogens in Chile is inadequate. Distribution and prevalence of wheat (Triticum aestivum L.) crown rot pathogens were examined in a survey of 48 commercial fields from December 2011 to February 2012 in southern Chile. These fields were located between Collipulli (37°56'00" S; 72°26'39" W) and Purranque (40°50'30" S; 73°22'03" W). Severity of crown rot d...
Rylev, Mette; Kilian, Mogens
. Some genetically distinct types of Porphyromonas gingivalis are more associated with disease than others, but additional work is required to relate this to clinical differences. CONCLUSIONS: Studies that take into account differences linked to the genetics of both patients and potential pathogens...
This study was conducted to determine the incidence of pathogenic microorganisms associated with dental caries and antimicrobial susceptibility test of some common dentifrice sold in Kano metropolis. A total of 50 samples were used in this study. The samples were taken using swab from human oral mucosa. The swabs ...
Teixeira, Paulo José Pereira Lima; Thomazella, Daniela Paula de Toledo; Reis, Osvaldo; do Prado, Paula Favoretti Vital; do Rio, Maria Carolina Scatolin; Fiorin, Gabriel Lorencini; José, Juliana; Costa, Gustavo Gilson Lacerda; Negri, Victor Augusti; Mondego, Jorge Maurício Costa; Mieczkowski, Piotr; Pereira, Gonçalo Amarante Guimarães
Witches' broom disease (WBD), caused by the hemibiotrophic fungus Moniliophthora perniciosa, is one of the most devastating diseases of Theobroma cacao, the chocolate tree. In contrast to other hemibiotrophic interactions, the WBD biotrophic stage lasts for months and is responsible for the most distinctive symptoms of the disease, which comprise drastic morphological changes in the infected shoots. Here, we used the dual RNA-seq approach to simultaneously assess the transcriptomes of cacao and M. perniciosa during their peculiar biotrophic interaction. Infection with M. perniciosa triggers massive metabolic reprogramming in the diseased tissues. Although apparently vigorous, the infected shoots are energetically expensive structures characterized by the induction of ineffective defense responses and by a clear carbon deprivation signature. Remarkably, the infection culminates in the establishment of a senescence process in the host, which signals the end of the WBD biotrophic stage. We analyzed the pathogen's transcriptome in unprecedented detail and thereby characterized the fungal nutritional and infection strategies during WBD and identified putative virulence effectors. Interestingly, M. perniciosa biotrophic mycelia develop as long-term parasites that orchestrate changes in plant metabolism to increase the availability of soluble nutrients before plant death. Collectively, our results provide unique insight into an intriguing tropical disease and advance our understanding of the development of (hemi)biotrophic plant-pathogen interactions. © 2014 American Society of Plant Biologists. All rights reserved.
This review provides abstracts of our research for which the year 2000 prize of The Japanese Society for Medical Mycology was awarded. The study consists of 4 fields: 1)Ultrastructure and biochemistry of the cell walls of dermatophytes. 2) Freeze-fracture electron microscopic study on the membrane systems of pathogenic fungi. 3) Action mechanisms of antifungal agents in terms of membrane structure and functions. 4) Dimorphism and virulence of pathogenic fungi in terms of molecular biology of membrane lipids. Since the detailed contents of these studies were reported in my previous review article (Jpn J Med Mycol 41: 211-217, 2000), I would like to mention these studies only briefly here, together with a detailed review of the septal cell wall architecture of dermatophytes, which I did not cover in my earlier articles.
The rhizosphere is an active interface where plants and microorganisms (pathogenic, beneficial and neutral) establish a complex and varied molecular dialogue, however knowledge of the functional mechanisms mediating interactions is still limited. Plants invest a significant proportion of their photosynthetically fixed carbon in maintaining the rhizosphere microbiome via root exudation and in return beneficial microbes provide profitable functions to the plant. The potential of naturally occur...
Full Text Available Pokkah Boeng is a serious disease of sugarcane, which can lead to devastating yield losses in crop-producing regions, including southern China. However, there is still uncertainty about the causal agent of the disease. Our aim was to isolate and characterize the pathogen through morphological, physiological, and molecular analyses. We isolated sugarcane-colonizing fungi in Fujian, China. Isolated fungi were first assessed for their cell wall degrading enzyme capabilities, and five isolates were identified for further analysis. Internal transcribed spacer sequencing revealed that these five strains are Fusarium, Alternaria, Phoma, Phomopsis, and Epicoccum. The Fusarium isolate was further identified as F. verticillioides after Calmodulin and EF-1α gene sequencing and microscopic morphology study. Pathogenicity assay confirmed that F. verticillioides was directly responsible for disease on sugarcane. Co-inoculation of F. verticillioides with other isolated fungi did not lead to a significant difference in disease severity, refuting the idea that other cellulolytic fungi can increase disease severity as an endophyte. This is the first report characterizing pathogenic F. verticillioides on sugarcane in southern China.
Abou-Zeid, A. M.
Full Text Available Twenty two plants were collected from Taif Governorate and identified as: Aerva lanata, Arnebia hispidissima, Artemisia judaica, Artemisia monosperma, Asphodelus aestives, Avena barbata, Capparis dcidua, Eucalyptus globulus, Euphorbia glomerifera, Foeniculum vulgare, Forsskaolea tenacissima, Juniperus procera, Launaea mucronata, Launaea sonchoides, Medicago sativa, Opuntia ficus, Phagnalon sinaicum, Prunus persica, Pulicaria crispa, Punica granatum, Rumex dentatus and Trichodesma calathiforme. Pathogenic fungi were isolated from some of these plants and identified as Alternaria alternata, Cephalosporium madurae, Cladosporium herbarum, Fusarium oxysporum, Humicola grisea, Penicillium chrysogenum and Ulocladium botrytis. Four antagonistic isolates were tested, 2 from Gliocladium fungus and 2 from Trichoderma fungus. We found that all the four antagonistic isolates (G. deliquescens, G. virens, T. viride and T. hamatum significantly inhibited the radial growth of the pathogenic fungi tested, with different ratios. The results indicated that the antibiotics produced by the antagonists were more effective than the fungus itself and differ with different fungi. Coating plant stems with antagonists or with antagonist extracts reduce the severity of the disease but not prevent it in all tested pathogens.
Abou-Zeid, A M; Altalhi, A D; Abd El-Fattah, R I
Twenty two plants were collected from Taif Governorate and identified as: Euphorbia glomerifera, Juniperus procera, Launaea mucronata, Capparis dcidua, Punica granatum, Opuntia ficus, Prunus persica, Eucalyptus globulus, Medicago sativa, Artemisia monosperma, Trichodesma calathiforme, Artemisia judaica, Foeniculum vulgare, Phagnalon sinaicum, Rumex dentatus, Asphodelus aestives, Pulicaria crispa, Launae sonchoides, Forsskaolea tenacissima, Arnebia hispidissima, Avena spp and Aerva lanata. Pathogenic fungi were isolated from some of these plants and identified as Alternaria alternate, Ulocladium botrytis, Cladosporium spp, Cephalosporium spp, Penicillium chrysogenum, Fusarium oxysporum and Humicola grisea. Four antagonistic isolates were tested, 2 from Gliocladium fungus and 2 from Trichoderma fungus. We found that all the four antagonistic isolates (G. deliquescens, G. virens, T. viride and T. hamatum) significantly inhibited the radial growth of the pathogenic fungi tested, with different ratios. The results indicated that the antibiotics produced by the antagonists were more effective than the fungus itself and differ with different fungi. Coating plant stems with antagonists or with antagonist extracts reduce the severity of the disease but not prevent it in all tested pathogens.
La Camera, Sylvain; Geoffroy, Pierrette; Samaha, Hala; Ndiaye, Abdoulaye; Rahim, Gwendoline; Legrand, Michel; Heitz, Thierry
Genes and proteins related to patatin, the major storage protein of potato tubers, have been identified in many plant species and shown to be induced by a variety of environmental stresses. The Arabidopsis patatin-like gene family (PLPs) comprises nine members, two of which (PLP2 and PLP7) are strongly induced in leaves challenged with fungal and bacterial pathogens. Here we show that accumulation of PLP2 protein in response to Botrytis cinerea or Pseudomonas syringae pv. tomato (avrRpt2) is dependent on jasmonic acid and ethylene signaling, but is not dependent on salicylic acid. Expression of a PLP2-green fluorescent protein (GFP) fusion protein and analysis of recombinant PLP2 indicates that PLP2 encodes a cytoplasmic lipid acyl hydrolase with wide substrate specificity. Transgenic plants with altered levels of PLP2 protein were generated and assayed for pathogen resistance. Plants silenced for PLP2 expression displayed enhanced resistance to B. cinerea, whereas plants overexpressing PLP2 were much more sensitive to this necrotrophic fungus. We also established a positive correlation between the level of PLP2 expression in transgenic plants and cell death or damage in response to paraquat treatment or infection by avirulent P. syringae. Interestingly, repression of PLP2 expression increased resistance to avirulent bacteria, while PLP2-overexpressing plants multiplied avirulent bacteria close to the titers reached by virulent bacteria. Collectively, the data indicate that PLP2-encoded lipolytic activity can be exploited by pathogens with different lifestyles to facilitate host colonization. In particular PLP2 potentiates plant cell death inflicted by Botrytis and reduces the efficiency of the hypersensitive response in restricting the multiplication of avirulent bacteria. Both effects are possibly mediated by providing fatty acid precursors of bioactive oxylipins.
Full Text Available Essential oil from Gaultheria procumbens is mainly composed of methylsalicylate (>96%, a compound which can be metabolized in plant tissues to salicylic acid, a phytohormone inducing plant immunity against microbial pathogens. The potential use of G. procumbens essential oil as a biocontrol agent was evaluated on the model plant Arabidopsis thaliana. Expression of a selection of defence genes was detected 1, 6 and 24 hours after essential oil treatment (0.1 ml/L using a high-throughput qPCR-based microfluidic technology. Control treatments included methyl jasmonate and a commercialized salicylic acid analog, benzo(1,2,3-thiadiazole-7carbothiolic acid (BTH. Strong induction of defence markers known to be regulated by the salicylic acid pathway was observed after the treatment with G. procumbens essential oil. Treatment induced the accumulation of total salicylic acid in the wild -type Arabidopsis line Col-0 and analysis of the Arabidopsis line sid2, mutated in a salicylic acid biosynthetic gene, revealed that approximately 30% of methylsalicylate sprayed on the leaves penetrated inside plant tissues and was demethylated by endogenous esterases. Induction of plant resistance by G. procumbens essential oil was tested following inoculation with a GFP-expressing strain of the Arabidopsis fungal pathogen Colletotrichum higginsianum. Flurorescence measurement of infected tissues revealed that treatments led to a strong reduction (60% of pathogen development and that the efficacy of the G. procumbens essential oil was similar to the commercial product BION®. Together, these results show that the G. procubens essential oil is a natural source of methylsalicylate which can be formulated to develop new biocontrol products.
Full Text Available Occurrence of culturable Fungi and Oomycota in root-soil habitat of potato cv. Owacja in organic and integrated production systems at Osiny (northern Poland was compared in 2008-2010. The densities of both pathogens were significantly greater in the organic system. The eudominant fungal taxa (with frequency > 10% in at least one habitat included species of Fusarium + Gibberella + Haematonectria, Penicillium, Phoma and Trichoderma. The dominant taxa (with frequency 5-10% included species from 13 genera. In the rhizoplane, rhizosphere and non-rhizosphere soil, the total density of potential pathogens was greater in the integrated system, and of potential antagonists in the organic system. Among eudominant and dominant pathogens, Fusarium oxysporum and Gibellulopsis nigrescens occurred at greater density in the integrated system and Haematonectria haematococca and Phoma spp. in the organic system. Among eudominant antagonists, Trichoderma species occurred at greater density in the organic system. The organic system provided more disease suppressive habitat than the integrated system. The occurrence of brown leaf spot and potato blight was however similar in both systems. The mean yield of organic potatoes (24.9 t · ha-1 was higher than the mean organic potato yield in Poland (21.0 t · ha-1 and similar to the mean in other European countries (Germany 25.1 t · ha-1, Great Britain 25.0 t · ha-1. The organic system, based on a 5-year rotation, with narrow-leafed lupin, white mustard and buckwheat as a cover crop, inorganic fertilization based on ground rock phosphate + potassium sulphate, and biological and chemical control of insects and diseases (Bacillus thuringiensis ssp. tenebrionis + copper hydroxide + copper oxychloride, may be recommended for use in central Europe.
Terentjeva, Margarita; Eizenberga, Inga; Valciņa, Olga; Novoslavskij, Aleksandr; Strazdiņa, Vita; Bērziņš, Aivars
The aim of this study was to detect the prevalence of Salmonella spp., Listeria monocytogenes, and Yersinia enterocolitica in freshwater fish in Latvia. In total, 235 samples, including freshly caught fish from fives lakes (n = 129) and fish from retail markets (n = 106), were collected from April 2014 to December 2014 in Latvia. Samples were tested according to International Organization for Standardization methods. No Salmonella spp. were found in fresh fish from lakes or in commercially available fish. In contrast, the overall prevalence of L. monocytogenes and Y. enterocolitica in freshwater fish was 13% (30 of 235) and 14% (34 of 235), respectively, and no significant difference between the prevalence of L. monocytogenes and Y. enterocolitica was observed (P > 0.05). All Y. enterocolitica isolates belonged to the nonpathogenic 1A biotype. Molecular serotyping of L. monocytogenes revealed that the most distributed serogroup was 1/2a-3a (65%), followed by 1/2c-3c (25%), 1/2b-3b (5%), and 4b, 4d, 4e (5%). The prevalence of L. monocytogenes and Y. enterocolitica in freshwater lake fish was 2% (2 of 129) and 3% (4 of 129), respectively. In contrast, the prevalence of L. monocytogenes and Y. enterocolitica in fish at retail markets was 26% (28 of 106) and 28% (30 of 106), respectively. In retail samples, 9 of 58 positive fish contained both L. monocytogenes and Y. enterocolitica. In general, differences in the prevalences of L. monocytogenes and Y. enterocolitica in retail samples were significantly higher than those in freshly caught fish (P Latvia.
Rodriguez, R J; Yoder, O C
Glomerella cingulata f. sp. phaseoli (Gcp) was transformed using either of two selectable markers: the amdS + gene of Aspergillus nidulans, which encodes acetamidase and permits growth on acetamide as the sole nitrogen source and the hygBR gene of Escherichia coli which encodes hygromycin B (Hy) phosphotransferase and permits growth in the presence of the antibiotic Hy. The amdS+ gene functioned in Gcp under control of A. nidulans regulatory signals and hygBR was expressed after fusion to a promoter from Cochliobolus heterostrophus, another filamentous ascomycete. Protoplasts to be transformed were generated with the digestive enzyme complex Novozym 234 and then were exposed to plasmid DNA in the presence of 10 mM CaCl2 and polyethylene glycol. Transformation occurred by integration of single or multiple copies of either the amdS+ or hygBR plasmid into the fungal genome. There was no evidence of autonomous plasmid replication. Transformants were mitotically stable on selective and nonselective media. However, transforming DNA in hygBR transformants was observed to occasionally rearrange during nonselective growth, resulting in fewer copies of the plasmid per genome. These transformants were capable of infecting bean (Phaseolus vulgaris), the Gcp host plant, and after recovery from infected tissue were found to have retained both the transforming DNA unrearranged in their genomes and the Hy resistance phenotype. All single-conidial cultures derived from both amdS+ and hygBR transformants had the transplanted phenotype, suggesting that transformants were homokaryons.
Hagen, Ferry; Ceresini, Paulo C; Polacheck, Itzhack; Ma, Hansong; van Nieuwerburgh, Filip; Gabaldón, Toni; Kagan, Sarah; Pursall, E Rhiannon; Hoogveld, Hans L; van Iersel, Leo J J; Klau, Gunnar W; Kelk, Steven M; Stougie, Leen; Bartlett, Karen H; Voelz, Kerstin; Pryszcz, Leszek P; Castañeda, Elizabeth; Lazera, Marcia; Meyer, Wieland; Deforce, Dieter; Meis, Jacques F; May, Robin C; Klaassen, Corné H W; Boekhout, Teun
Over the past two decades, several fungal outbreaks have occurred, including the high-profile 'Vancouver Island' and 'Pacific Northwest' outbreaks, caused by Cryptococcus gattii, which has affected hundreds of otherwise healthy humans and animals. Over the same time period, C. gattii was the cause of several additional case clusters at localities outside of the tropical and subtropical climate zones where the species normally occurs. In every case, the causative agent belongs to a previously rare genotype of C. gattii called AFLP6/VGII, but the origin of the outbreak clades remains enigmatic. Here we used phylogenetic and recombination analyses, based on AFLP and multiple MLST datasets, and coalescence gene genealogy to demonstrate that these outbreaks have arisen from a highly-recombining C. gattii population in the native rainforest of Northern Brazil. Thus the modern virulent C. gattii AFLP6/VGII outbreak lineages derived from mating events in South America and then dispersed to temperate regions where they cause serious infections in humans and animals.
Silva, Kaltz V S; Lima, Maria I O; Cardoso, Gustavo N; Santos, Aldeir S; Silva, Gezaíldo S; Pereira, Fillipe O
In humans worldwide, Microsporum sp. is a frequent agent of dermatophytsosis. When considering the emergence of resistant fungi and the clinical relevance of dermatophytosis, terpene antifungal activity is of great interest. Linalool is a monoterpene alcohol with pharmacological properties. In this study, antifungal in vitro activity of linalool and ketoconazole (as a positive control) were evaluated against clinical isolates of M. canis and M. gypseum. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of each drug were determined by broth microdilution. The effects of the drugs (1/2MIC, MIC, 2xMIC) on radial mycelial growth, conidial production and germination were analysed. The effect on the fungal cell membrane (release of intracellular material) was also investigated. Linalool (MIC: 128 μg/mL) and ketoconazole (MIC: 64 μg/mL) were effective in inhibiting all dermatophytes studied. The MFC values of linalool ranged between 128 and 256 μg/mL, whereas ketoconazole showed MFC values of from 64 to 256 μg/mL. Linalool (at MIC and 2xMIC) and ketoconazole (at 1/2MIC, MIC, 2xMIC) inhibited mycelial growth (P Linalool caused leakage of intracellular material. Our study supports the use of linalool as a potential antifungal agent against M. canis and M. gypseum. © 2017 Blackwell Verlag GmbH.
Carroll, Cassandra S; Grieve, Clark L; Murugathasan, Indu; Bennet, Andrew J; Czekster, Clarissa M; Liu, Huanting; Naismith, James; Moore, Margo M
Iron is essential for growth and in low iron environments such as serum many bacteria and fungi secrete ferric iron-chelating molecules called siderophores. All fungi produce hydroxamate siderophores with the exception of Mucorales fungi, which secrete rhizoferrin, a polycarboxylate siderophore. Here we investigated the biosynthesis of rhizoferrin by the opportunistic human pathogen, Rhizopus delemar. We searched the genome of R. delemar 99-880 for a homologue of the bacterial NRPS-independent siderophore (NIS) protein, SfnaD, that is involved in biosynthesis of staphyloferrin A in Staphylococcus aureus. A protein was identified in R. delemar with 22% identity and 37% similarity with SfnaD, containing an N-terminal IucA/IucC family domain, and a C-terminal conserved ferric iron reductase FhuF-like transporter domain. Expression of the putative fungal rhizoferrin synthetase (rfs) gene was repressed by iron. The rfs gene was cloned and expressed in E.coli and siderophore biosynthesis from citrate and diaminobutane was confirmed using high resolution LC-MS. Substrate specificity was investigated showing that Rfs produced AMP when oxaloacetic acid, tricarballylic acid, ornithine, hydroxylamine, diaminopentane and diaminopropane were employed as substrates. Based on the production of AMP and the presence of a mono-substituted rhizoferrin, we suggest that Rfs is a member of the superfamily of adenylating enzymes. We used site-directed mutagenesis to mutate selected conserved residues predicted to be in the Rfs active site. These studies revealed that H484 is essential for Rfs activity and L544 may play a role in amine recognition by the enzyme. This study on Rfs is the first characterization of a fungal NIS enzyme. Future work will determine if rhizoferrin biosynthesis is required for virulence in Mucorales fungi. Copyright © 2017 Elsevier Ltd. All rights reserved.
With the advent of 21st century technology that has resulted in the development of sophisticated equipments, blood supply is thought to be safer than ever. This study therefore, investigates the incidence and prevalence of transfusion transmitted infections in patients. The study was carried out on 55 hospitalized cohorts who ...
Gaddis, Nathan C.; Aballay, Alejandro
In the past decade, Caenorhabditis elegans has been used to dissect several genetic pathways involved in immunity; however, little is known about transcription factors that regulate the expression of immune effectors. C. elegans does not appear to have a functional homolog of the key immune transcription factor NF-κB. Here we show that that the intestinal GATA transcription factor ELT-2 is required for both immunity to Salmonella enterica and expression of a C-type lectin gene, clec-67, which is expressed in the intestinal cells and is a good marker of S. enterica infection. We also found that ELT-2 is required for immunity to Pseudomonas aeruginosa, Enterococcus faecalis, and Cryptococcus neoformans. Lack of immune inhibition by DAF-2, which negatively regulates the FOXO transcription factor DAF-16, rescues the hypersusceptibility to pathogens phenotype of elt-2(RNAi) animals. Our results indicate that ELT-2 is part of a multi-pathogen defense pathway that regulates innate immunity independently of the DAF-2/DAF-16 signaling pathway. PMID:17183709
Germain, H; Bergeron, M-J; Bernier, L; Laflamme, G; Hamelin, R C
The basidiomycetous fungus Onnia tomentosa is one of the most widespread root rot pathogens in North America. Although the disease is more severe on spruce and pine trees, this pathogen can infect several coniferous species. To study the population structure of O. tomentosa, we harvested 180 basidiocarps in a 45-year-old white spruce plantation in western Quebec in autumn 1997 and extracted DNA directly from individual basidiocarps. Using a combination of spatial coordinates and molecular data based on the analysis of two mitochondrial and three nuclear loci, we measured the average genet size and molecular diversity and assessed the relative contribution of basidiospores and vegetative growth to the stand colonization. Most of the sampled basidiocarps that clustered spatially belonged to the same genet. A total of 37 discrete multilocus genets of an average size of 3.42 m were obtained. The genet size distribution was skewed towards smaller genets (3 m). The nuclear loci were in Hardy-Weinberg equilibrium in the larger genets, but not in the smaller genets, which displayed a deficiency of heterozygotes. This suggests a Wahlund effect, whereby different colonization events resulted in expected heterozygosity higher than observed heterozygosity. Using an estimate of the growth rate of the fungus, only a few of the largest genets were approximately the age of the plantation. These observations are consistent with the colonization by basidiospores subsequent to site preparation and tree planting followed by secondary colonization events and vegetative spread.
Jong H Kim
Full Text Available The aim of this study was to examine two benzo analogs, octylgallate (OG and veratraldehyde (VT, as antifungal agents against strains of Aspergillus parasiticus and A. flavus (toxigenic or atoxigenic. Both toxigenic and atoxigenic strains used were capable of producing kojic acid, another cellular secondary product. A. fumigatus was used as a genetic model for this study. When applied independently, OG exhibits considerably higher antifungal activity compared to VT. The minimum inhibitory concentrations (MICs of OG were 0.3 - 0.5 mM, while that of VT were 3.0 - 5.0 mM in agar plate-bioassays. OG or VT in concert with the fungicide kresoxim methyl (Kre-Me; strobilurin greatly enhanced sensitivity of Aspergillus strains to Kre-Me. The combination with OG also overcame the tolerance of A. fumigatus mitogen-activated protein kinase (MAPK mutants to Kre-Me. The degree of compound interaction resulting from chemosensitization of the fungi by OG was determined using checkerboard bioassays, where synergistic activity greatly lowered MICs or minimum fungicidal concentrations. However, the control chemosensitizer benzohydroxamic acid, an alternative oxidase inhibitor conventionally applied in concert with strobilurin, did not achieve synergism. The level of antifungal or chemosensitizing activity was also compound - strain specific, indicating differential susceptibility of tested strains to OG or VT, and/or heat stress. Besides targeting the antioxidant system, OG also negatively affected the cell wall-integrity pathway, as determined by the inhibition of Saccharomyces cerevisiae cell wall-integrity MAPK pathway mutants. We concluded that certain benzo analogs effectively inhibit fungal growth. They possess chemosensitizing capability to increase efficacy of Kre-Me and thus could reduce effective dosages of strobilurins and alleviate negative side effects associated with current antifungal practices. OG also exhibits moderate antiaflatoxigenic activity.
O. A. Drehval
Full Text Available The antagonistic activity of 23 strains of micromycetes belonging to different taxonomic groups, against phythopathogenic bacteria and fungi was studied. The antagonistic activity of the micromycetes was tested by agar diffusion (the method of blocks. For the determination of the influence of the micromycetes on plants, spring barley seeds were treated by cultural liquid of fungi (dilution 1 : 10 for 24 hours and germinated in Petri dishes on moist filter paper. Two strains Trichoderma longibrachiatum 17 and T. lignorum 14 showed the highest antagonistic activity against the phytopathogenic bacteria and fungi. T. longibrachiatum 17 actively suppressed the growth of fungi Fusarium oxysporum 54201, F. culmorum 50716, F. oxysporum 12, F. moniliforme 23, Cladosporium herbarum 16878, Alternaria alternata 16, Aspergillus niger 25 and bacteria Agrobacterium tumefaciens 8628, Xanthomonas campestris 8003b, Pectobacterium carotovorum 8982, Pseudomonas syringae pv. atrofaciens 8254, P. syringae pv. lachrymans 7595, zones inhibition of growth were 20.7–38.3 and 14.7–24.7 mm, respectively. The strain of T. lignorum 14 inhibited the growth of fungi F. culmorum 50716, C. herbarum 16878, F. moniliforme 23, A. alternata 16, A. niger 25 and bacteria A. tumefaciens 8628, P. carotovorum 8982, P. syringae pv. atrofaciens 8254, P. syringae pv. lachrymans 7595, zones of inhibition of growth were 14.0–38.7 and 12.3–23.3 mm, respectively. Treatment of spring barley seeds by T. longibrachiatum 17 cultural liquid showed a positive effect on seed germination, both strains T. longibrachiatum 17 and T. lignorum 14 increased the dry weight of the roots (by 17.5% and 22.0%, respectively and the stems (by 8.0% of spring barley plants compared with the water-treated controls. The results presented in this article indicate that the strains T. longibrachiatum 17 and T. lignorum 14 can be recommended as promising microbial agents to protect plants from fungal and
Full Text Available In this study, we characterized the miR482 family in cotton using existing small RNA datasets and the recently released draft genome sequence of Gossypium raimondii, a diploid cotton species whose progenitor is the putative contributor of the Dt (representing the D genome of tetraploid genome of the cultivated tetraploid cotton species G. hirsutum and G. barbadense. Of the three ghr-miR482 members reported in G. hirsutum, ghr-miR482a has no homolog in G. raimondii, ghr-miR482b and ghr-miR482c each has a single homolog in G. raimondii. Gra-miR482d has five homologous loci (gra-miR482d, f-i in G. raimondii and also exists in G. hirsutum (ghr-miR482d. A variant, miR482.2 that is a homolog of miR2118 in other species, is produced from several GHR-MIR482 loci in G. hirsutum. Approximately 12% of the G. raimondii NBS-LRR genes were predicted targets of various members of the gra-miR482 family. Based on the rationale that the regulatory relationship between miR482 and NBS-LRR genes will be conserved in G. raimondii and G. hirsutum, we investigated this relationship using G. hirsutum miR482 and G. raimondii NBS-LRR genes, which are not currently available in G. hirsutum. Ghr-miR482/miR482.2-mediated cleavage was confirmed for three of the four NBS-LRR genes analysed. As in tomato, miR482-mediated cleavage of NBS-LRR genes triggered production of phased secondary small RNAs in cotton. In seedlings of the susceptible cultivar Sicot71 (G. hirsutum infected with the fungal pathogen Verticillium dahliae, the expression levels of ghr-miR482b/miR482b.2, ghr-miR482c and ghr-miR482d.2 were down-regulated, and several NBS-LRR targets of ghr-miR482c and ghr-miR482d were up-regulated. These results imply that, like tomato plants infected with viruses or bacteria, cotton plants are able to induce expression of NBS-LRR defence genes by suppression of the miRNA-mediated gene silencing pathway upon fungal pathogen attack.
B Sajeewa Amaradasa
Full Text Available Pathogen exposure to sublethal doses of fungicides may result in mutations that may represent an important and largely overlooked mechanism of introducing new genetic variation into strictly clonal populations, including acquisition of fungicide resistance. We tested this hypothesis using the clonal plant pathogen, Sclerotinia sclerotiorum. Nine susceptible isolates were exposed independently to five commercial fungicides with different modes of action: boscalid (respiration inhibitor, iprodione (unclear mode of action, thiophanate methyl (inhibition of microtubulin synthesis and azoxystrobin and pyraclostrobin (quinone outside inhibitors. Mycelium of each isolate was inoculated onto a fungicide gradient and sub-cultured from the 50-100% inhibition zone for 12 generations and experiment repeated. Mutational changes were assessed for all isolates at six neutral microsatellite (SSR loci and for a subset of isolates using amplified fragment length polymorphisms (AFLPs. SSR analysis showed 12 of 85 fungicide-exposed isolates had a total of 127 stepwise mutations with 42 insertions and 85 deletions. Most stepwise deletions were in iprodione- and azoxystrobin-exposed isolates (n = 40/85 each. Estimated mutation rates were 1.7 to 60-fold higher for mutated loci compared to that expected under neutral conditions. AFLP genotyping of 33 isolates (16 non-exposed control and 17 fungicide exposed generated 602 polymorphic alleles. Cluster analysis with principal coordinate analysis (PCoA and discriminant analysis of principal components (DAPC identified fungicide-exposed isolates as a distinct group from non-exposed control isolates (PhiPT = 0.15, P = 0.001. Dendrograms based on neighbor-joining also supported allelic variation associated with fungicide-exposure. Fungicide sensitivity of isolates measured throughout both experiments did not show consistent trends. For example, eight isolates exposed to boscalid had higher EC50 values at the end of the
Paudyal, Narayan; Anihouvi, Victor; Hounhouigan, Joseph
, Staphylococcus aureus and Listeria monocytogenes were the most frequently reported organisms in those studies. Although the data were highly heterogeneous, a striking feature is high prevalence of the major pathogens in RTE foods, almost as high as in raw foods. E. coli averaged at 37.6% in raw foods and 31...... for general analysis, while 66 papers on contamination of pathogenic bacteria were used for meta-analysis of prevalence. The food items were split into two categories: raw foods and ready-to-eat (RTE) foods (including street food and beverages) for meta-analysis. Majority of the reviewed studies (67.2%, 78...... the prevalence of foodborne pathogens in seven African countries (Benin, Botswana, Ghana, Kenya, Nigeria, Sudan and Uganda) from papers in regional or international journals published between January 2000 and December 2015. One hundred and sixteen publications that dealt with food microbiology were reviewed...
Dewdney, J; Reuber, T L; Wildermuth, M C; Devoto, A; Cui, J; Stutius, L M; Drummond, E P; Ausubel, F M
To identify components of the defense response that limit growth of a biotrophic fungal pathogen, we isolated Arabidopsis mutants with enhanced disease susceptibility to Erysiphe orontii. Our initial characterization focused on three mutants, eds14, eds15, and eds16. None of these is considerably more susceptible to a virulent strain of the bacterial pathogen Pseudomonas syringae pv. maculicola (Psm). All three mutants develop a hypersensitive response when infiltrated with Psm expressing the avirulence gene avrRpt2, which activates resistance via the LZ-NBS/LRR resistance protein encoded by RPS2. The growth of Psm(avrRpt2), while somewhat greater in the mutants than in the wild type, is less than growth of the isogenic virulent strain. These results indicate that resistance mediated via LZ-NBS/LRR R genes is functional. Analysis of the growth of avirulent Peronospora parasitica strains showed that the resistance pathway utilized by TIR-NBS/LRR R genes is also operative in all three mutants. Surprisingly, only eds14 and eds16 were more susceptible to Erysiphe cichoracearum. Analysis of the expression profiles of PR-1, BGL2, PR-5 and PDF1.2 in eds14, eds15, and eds16 revealed differences from the wild type for all the lines. In contrast, these mutants were not significantly different from wild type in the deposition of callose at sites of E. orontii penetration. All three mutants have reduced levels of salicylic acid after infection. eds16 was mapped to the lower arm of chromosome I and found by complementation tests to be allelic to the salicylic acid-deficient mutant sid2.
Groner, Maya L; Buck, Julia C; Gervasi, Stephanie; Blaustein, Andrew R; Reinert, Laura K; Rollins-Smith, Louise A; Bier, Mark E; Hempel, John; Relyea, Rick A
For the past several decades, amphibian populations have been decreasing around the globe at an unprecedented rate. Batrachochytrium dendrobatidis (Bd), the fungal pathogen that causes chytridiomycosis in amphibians, is contributing to amphibian declines. Natural and anthropogenic environmental factors are hypothesized to contribute to these declines by reducing the immunocompetence of amphibian hosts, making them more susceptible to infection. Antimicrobial peptides (AMPs) produced in the granular glands of a frog's skin are thought to be a key defense against Bd infection. These peptides may be a critical immune defense during metamorphosis because many acquired immune functions are suppressed during this time. To test if stressors alter AMP production and survival of frogs exposed to Bd, we exposed wood frog (Lithobates sylvaticus) tadpoles to the presence or absence of dragonfly predator cues crossed with a single exposure to three nominal concentrations of the insecticide malathion (0, 10, or 100 parts per billion [ppb]). We then exposed a subset of post-metamorphic frogs to the presence or absence of Bd zoospores and measured frog survival. Although predator cues and malathion had no effect on survival or size at metamorphosis, predator cues increased the time to metamorphosis by 1.5 days and caused a trend of a 20% decrease in hydrophobic skin peptides. Despite this decrease in peptides determined shortly after metamorphosis, previous exposure to predator cues increased survival in both Bd-exposed and unexposed frogs several weeks after metamorphosis. These results suggest that exposing tadpoles to predator cues confers fitness benefits later in life.
Pedras, M Soledade C; Minic, Zoran
Alternaria brassicicola is a fungal pathogen of many agriculturally important cruciferous crops. Cyclobrassinin hydrolase (CH) is an enzyme produced by A. brassicicola that catalyzes the transformation of the cruciferous phytoalexin cyclobrassinin into S-methyl[(2-sulfanyl-1H-indolyl-3)methyl]carbamothioate. The purification and characterization of CH was performed using a four-step chromatography method. SDS-PAGE and gel exclusion chromatography indicated that CH is a tetrameric protein with molecular mass of 330 kDa. Sequence analysis and chemical modification of CH with selective reagents suggested that the enzyme mediates hydrolysis of cyclobrassinin using a catalytic amino acid triad. Enzyme kinetic studies using cyclobrassinin and 1-methylcyclobrassinin as substrates revealed that CH displayed positive substrate cooperativity. Investigation of the effect of nine phytoalexins and two derivatives on the activity of CH indicated that six compounds displayed inhibitory activity: brassilexin, 1-methylbrassilexin, dioxibrassinin, camalexin, brassicanal A and sinalexin. The enzyme kinetics of CH strongly suggested that brassilexin and 1-methylbrassilexin are noncompetitive inhibitors of CH activity, and that camalexin is a competitive inhibitor while dioxibrassinin inhibits CH through a mixed mechanism. The phytoalexin brassilexin is the most effective inhibitor of CH (K(i)=32 ± 9 μM). These results suggest that crops able to accumulate higher concentration of brassilexin would display higher resistance levels to the fungus. Copyright © 2013 Elsevier Ltd. All rights reserved.
Full Text Available In plant cells, many cysteine proteinases (CPs are synthesized as precursors in the endoplasmic reticulum, and then are subject to post-translational modifications to form the active mature proteinases. They participate in various cellular and physiological functions. Here, AcCP2, a CP from pineapple fruit (Ananas comosus L. belonging to the C1A subfamily is analyzed based on the molecular modeling and homology alignment. Transcripts of AcCP2 can be detected in the different parts of fruits (particularly outer sarcocarps, and gradually increased during fruit development until maturity. To analyze the substrate specificity of AcCP2, the recombinant protein was overexpressed and purified from Pichia pastoris. The precursor of purified AcCP2 can be processed to a 25 kDa active form after acid treatment (pH 4.3. Its optimum proteolytic activity to Bz-Phe-Val-Arg-NH-Mec is at neutral pH. In addition, the overexpression of AcCP2 gene in Arabidopsis thaliana can improve the resistance to fungal pathogen of Botrytis cinerea. These data indicate that AcCP2 is a multifunctional proteinase, and its expression could cause fruit developmental characteristics of pineapple and resistance responses in transgenic Arabidopsis plants.
Soria-Guerra, Ruth Elena; Rosales-Mendoza, Sergio; Chang, Sungyul; Haudenshield, James S; Zheng, Danman; Rao, Suryadevara S; Hartman, Glen L; Ghabrial, Said A; Korban, Schuyler S
To compare transcription profiles in genotypes of Glycine tomentella that are differentially sensitive to soybean rust, caused by the fungal pathogen Phakopsora pachyrhizi, four cDNA libraries were constructed using the suppression subtractive hybridization method. Libraries were constructed from rust-infected and non-infected leaves of resistant (PI509501) and susceptible (PI441101) genotypes of G. tomentella, and subjected to subtractive hybridization. A total of 1,536 sequences were obtained from these cDNA libraries from which 195 contigs and 865 singletons were identified. Of these sequenced cDNA clones, functions of 646 clones (61%) were determined. In addition, 160 clones (15%) had significant homology to hypothetical proteins; while the remaining 254 clones (24%) did not reveal any hits. Of those 646 clones with known functions, different genes encoding protein products involved in metabolism, cell defense, energy, protein synthesis, transcription, and cellular transport were identified. These findings were subsequently confirmed by real time RT-PCR and dot blot hybridization.
Munafo, John P; Gianfagna, Thomas J
Botrytis cinerea Pers. Fr. is a plant pathogenic fungus and the causal organism of blossom blight of Easter lily (Lilium longiflorum Thunb.). Easter lily is a rich source of steroidal glycosides, compounds which may play a role in the plant-pathogen interaction of Easter lily. Five steroidal glycosides, including two steroidal glycoalkaloids and three furostanol saponins, were isolated from L. longiflorum and evaluated for fungal growth inhibition activity against B. cinerea, using an in vitro plate assay. All of the compounds showed fungal growth inhibition activity; however, the natural acetylation of C-6''' of the terminal glucose in the steroidal glycoalkaloid, (22R,25R)-spirosol-5-en-3β-yl O-α-L-rhamnopyranosyl-(1→2)-[6-O-acetyl-β-D-glucopyranosyl-(1→4)]-β-D-glucopyranoside (2), increased antifungal activity by inhibiting the rate of metabolism of the compound by B. cinerea. Acetylation of the glycoalkaloid may be a plant defense response to the evolution of detoxifying mechanisms by the pathogen. The biotransformation of the steroidal glycoalkaloids by B. cinerea led to the isolation and characterization of several fungal metabolites. The fungal metabolites that were generated in the model system were also identified in Easter lily tissues infected with the fungus by LC-MS. In addition, a steroidal glycoalkaloid, (22R,25R)-spirosol-5-en-3β-yl O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranoside (6), was identified as both a fungal metabolite of the steroidal glycoalkaloids and as a natural product in L. longiflorum for the first time.
Mohammed Taha Moustafa
Full Text Available Nanotechnology are fast advancing and currently became more effective than the conventional technologies used in water treatment that offers safe opportunities for using unconventional water supply sources. Fungi are more versatile in growth and metal tolerance in contrast to bacterial population. This work aims to demonstrate the extracellular synthesis of silver nanoparticle by using two filamentous fungi Penciillium Citreonigum Dierck and Scopulaniopsos brumptii Salvanet-Duval isolated from Lake Burullus, examine the biosynthesized nano-silver particles by UV–vis spectroscopy, transmission electron microscopy (TEM. The functional group of protein molecules surrounding AgNPs was identified using Fourier transform infrared (FTIR analysis. Check the antibacterial activity of biosynthesized silver nanoparticles at two concentrations (550.7 and 676.9 mg/l and interact it with bacteria for different durations (15, 60 and 120 min. Polyurethane foam was used as silver carrier and nano-silver solution for the removal of pathogenic bacteria in polluted water. The synthesized AgNPs showed an excellent antibacterial property on gram positive and gram negative bacterial strains.
Liñeiro, Eva; Chiva, Cristina; Cantoral, Jesús M; Sabidó, Eduard; Fernández-Acero, Francisco Javier
Botrytis cinerea is a model fungus for the study of phytopathogenicity that exhibits a wide arsenal of tools to infect plant tissues. Most of these factors are related to signal transduction cascades, in which membrane proteins play a key role as a bridge between environment and intracellular molecular processes. This work describes the first description of the membranome of Botrytis under different pathogenicity conditions induced by different plant-based elicitors: glucose and tomato cell wall (TCW). A discovery proteomics analysis of membrane proteins was carried out by mass spectrometry. A total of 2794 proteins were successfully identified, 46% of them were classified as membrane proteins based on the presence of transmembrane regions and lipidation. Further analyses showed significant differences in the membranome composition depending on the available carbon source: 804 proteins were exclusively identified when the fungus was cultured with glucose as a sole carbon source, and 251 proteins were exclusively identified with TCW. Besides, among the 1737 common proteins, a subset of 898 proteins presented clear differences in their abundance. GO enrichment and clustering interaction analysis revealed changes in the composition of membranome with increase of signalling function in glucose conditions and carbohydrate degradation process in TCW conditions. All MS data have been deposited in the ProteomeXchange with identifier PXD003099 (http://proteomecentral.proteomexchange.org/dataset/PXD003099). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Sharifzadeh, A; Javan, A Jebeli; Shokri, H; Abbaszadeh, S; Keykhosravy, K
To determine the antioxidant and antifungal activities of the essential oils from five aromatic herbs, including Thymus vulgaris, Chamaemelum nobile, Ziziphora clinopodioides, Zingiber officinale and Cuminum cyminum, against different Aspergillus and Penicillium species. The oils were subjected to screening for their possible antioxidant activity using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The susceptibility test for the oils was carried out in terms of minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) using microdilution method. The values of the essential oils in DPPH assay were as follows: T. vulgaris (450.11±5.23 μg/mL), Ch. nobile (602.73±4.8 μg/mL), Ziz. clinopodioides (1238.82±9.3 μg/mL), Cu. cyminum (1255.52±8.92 μg/mL) and Zin. officinale (5595.06±8.24 μg/mL). Our findings also indicated a strong activity against tested fungi for the oil of T. vulgaris (1250 μg/mL), followed by Cu. cyminum (1416 μg/mL), Zin. officinale (1833 μg/mL), Ziz. clinopodioides (2166 μg/mL) and Ch. nobile (3750 μg/mL). This study confirmed the excellent antifungal and antioxidant properties of the essential oils, especially T. vulgaris, against foodborne pathogenic fungi. Owing to their strong protective features, these oils could be used in ethno-medicine as preventers of lipid peroxidation and cellular damage, and in food industries as preservers of foodstuffs against spoilage fungi. Also, they could be the candidates to develop new antibiotics and disinfectants to control infective agents. Copyright © 2015 Elsevier Masson SAS. All rights reserved.
Lee, I. Russel; Chow, Eve W. L.; Morrow, Carl A.; Djordjevic, Julianne T.; Fraser, James A.
Proper regulation of metabolism is essential to maximizing fitness of organisms in their chosen environmental niche. Nitrogen metabolite repression is an example of a regulatory mechanism in fungi that enables preferential utilization of easily assimilated nitrogen sources, such as ammonium, to conserve resources. Here we provide genetic, transcriptional, and phenotypic evidence of nitrogen metabolite repression in the human pathogen Cryptococcus neoformans. In addition to loss of transcriptional activation of catabolic enzyme-encoding genes of the uric acid and proline assimilation pathways in the presence of ammonium, nitrogen metabolite repression also regulates the production of the virulence determinants capsule and melanin. Since GATA transcription factors are known to play a key role in nitrogen metabolite repression, bioinformatic analyses of the C. neoformans genome were undertaken and seven predicted GATA-type genes were identified. A screen of these deletion mutants revealed GAT1, encoding the only global transcription factor essential for utilization of a wide range of nitrogen sources, including uric acid, urea, and creatinine—three predominant nitrogen constituents found in the C. neoformans ecological niche. In addition to its evolutionarily conserved role in mediating nitrogen metabolite repression and controlling the expression of catabolic enzyme and permease-encoding genes, Gat1 also negatively regulates virulence traits, including infectious basidiospore production, melanin formation, and growth at high body temperature (39°–40°). Conversely, Gat1 positively regulates capsule production. A murine inhalation model of cryptococcosis revealed that the gat1Δ mutant is slightly more virulent than wild type, indicating that Gat1 plays a complex regulatory role during infection. PMID:21441208
Baumgartner, Kendra; Fujiyoshi, Phillip; Foster, Gary D; Bailey, Andy M
Armillaria root disease is one of the most damaging timber and fruit tree diseases in the world. Despite its economic importance, many basic questions about the biology of the causal fungi, Armillaria spp., are unanswered. For example, Armillaria undergoes matings between diploid and haploid mycelia, which can result in a recombinant diploid without meiosis. Evidence of such somatic recombination in natural populations suggests that this reproductive mode may affect the pathogen's ecology. Investigations of the mechanisms and adaptive consequences of somatic recombination are, however, hampered by the lack of a method to reliably synthesize somatic recombinants. Here we report the first genetic transformation system for the genus Armillaria. We transformed A. mellea with selective markers for use in diploid-haploid matings to reliably synthesize somatic recombinants. This was accomplished with Agrobacterium tumefaciens carrying pBGgHg, which carries the hygromycin phosphotransferase gene (hph). hph was integrated into transformants, as evidenced by serial transfer to selective media, PCR, reverse transcription-PCR (RT-PCR), and Southern hybridization. Nuclear and mitochondrial markers were developed to genotype synthesized mycelia. In matings between a wild-type diploid and hygromycin-resistant haploids (transgenic), we identified recombinant, hygromycin-resistant diploids and, additionally, hygromycin-resistant triploids, all with the mitochondrial haplotype of the haploid partner. Our approach created no mycelium in which the haploid nucleus was replaced by the diploid nucleus, the typical outcome of diploid-haploid matings in Armillaria. This genetic transformation system, in combination with new markers to track chromosomal and cytoplasmic inheritance in A. mellea, will advance research aimed at characterizing the significance of somatic recombination in the ecology of this important fungus.
Baumgartner, Kendra; Fujiyoshi, Phillip; Foster, Gary D.; Bailey, Andy M.
Armillaria root disease is one of the most damaging timber and fruit tree diseases in the world. Despite its economic importance, many basic questions about the biology of the causal fungi, Armillaria spp., are unanswered. For example, Armillaria undergoes matings between diploid and haploid mycelia, which can result in a recombinant diploid without meiosis. Evidence of such somatic recombination in natural populations suggests that this reproductive mode may affect the pathogen's ecology. Investigations of the mechanisms and adaptive consequences of somatic recombination are, however, hampered by the lack of a method to reliably synthesize somatic recombinants. Here we report the first genetic transformation system for the genus Armillaria. We transformed A. mellea with selective markers for use in diploid-haploid matings to reliably synthesize somatic recombinants. This was accomplished with Agrobacterium tumefaciens carrying pBGgHg, which carries the hygromycin phosphotransferase gene (hph). hph was integrated into transformants, as evidenced by serial transfer to selective media, PCR, reverse transcription-PCR (RT-PCR), and Southern hybridization. Nuclear and mitochondrial markers were developed to genotype synthesized mycelia. In matings between a wild-type diploid and hygromycin-resistant haploids (transgenic), we identified recombinant, hygromycin-resistant diploids and, additionally, hygromycin-resistant triploids, all with the mitochondrial haplotype of the haploid partner. Our approach created no mycelium in which the haploid nucleus was replaced by the diploid nucleus, the typical outcome of diploid-haploid matings in Armillaria. This genetic transformation system, in combination with new markers to track chromosomal and cytoplasmic inheritance in A. mellea, will advance research aimed at characterizing the significance of somatic recombination in the ecology of this important fungus. PMID:20952653
Full Text Available We previously characterized members of the Myb protein family, MYT1 and MYT2, in Fusarium graminearum. MYT1 and MYT2 are involved in female fertility and perithecium size, respectively. To expand knowledge of Myb proteins in F. graminearum, in this study, we characterized the functions of the MYT3 gene, which encodes a putative Myb-like transcription factor containing two Myb DNA-binding domains and is conserved in the subphylum Pezizomycotina of Ascomycota. MYT3 proteins were localized in nuclei during most developmental stages, suggesting the role of MYT3 as a transcriptional regulator. Deletion of MYT3 resulted in impairment of conidiation, germination, and vegetative growth compared to the wild type, whereas complementation of MYT3 restored the wild-type phenotype. Additionally, the Δmyt3 strain grew poorly on nitrogen-limited media; however, the mutant grew robustly on minimal media supplemented with ammonium. Moreover, expression level of nitrate reductase gene in the Δmyt3 strain was decreased in comparison to the wild type and complemented strain. On flowering wheat heads, the Δmyt3 strain exhibited reduced pathogenicity, which corresponded with significant reductions in trichothecene production and transcript levels of trichothecene biosynthetic genes. When the mutant was selfed, mated as a female, or mated as a male for sexual development, perithecia were not observed on the cultures, indicating that the Δmyt3 strain lost both male and female fertility. Taken together, these results demonstrate that MYT3 is required for pathogenesis and sexual development in F. graminearum, and will provide a robust foundation to establish the regulatory networks for all Myb-like proteins in F. graminearum.
Tzeng, T. H.; Lyngholm, L. K.; Ford, C. F.; Bronson, C. R.
A restriction fragment length polymorphism (RFLP) map has been constructed of the nuclear genome of the plant pathogenic ascomycete Cochliobolus heterostrophus. The segregation of 128 RFLP and 4 phenotypic markers was analyzed among 91 random progeny of a single cross; linkages were detected among 126 of the markers. The intact chromosomal DNAs of the parents and certain progeny were separated using pulsed field gel electrophoresis and hybridized with probes used to detect the RFLPs. In this way, 125 markers were assigned to specific chromosomes and linkages among 120 of the markers were confirmed. These linkages totalled 941 centimorgans (cM). Several RFLPs and a reciprocal translocation were identified tightly linked to Tox1, a locus controlling host-specific virulence. Other differences in chromosome arrangement between the parents were also detected. Fourteen gaps of at least 40 cM were identified between linkage groups on the same chromosomes; the total map length was therefore estimated to be, at a minimum, 1501 cM. Fifteen A chromosomes ranging from about 1.3 megabases (Mb) to about 3.7 Mb were identified; one of the strains also has an apparent B chromosome. This chromosome appears to be completely dispensable; in some progeny, all of 15 markers that mapped to this chromosome were absent. The total genome size was estimated to be roughly 35 Mb. Based on these estimates of map length and physical genome size, the average kb/cM ratio in this cross was calculated to be approximately 23. This low ratio of physical to map distance should make this RFLP map a useful tool for cloning genes. PMID:1346261
Zhang, Tao; Victor, Tanya R; Rajkumar, Sunanda S; Li, Xiaojiang; Okoniewski, Joseph C; Hicks, Alan C; Davis, April D; Broussard, Kelly; LaDeau, Shannon L; Chaturvedi, Sudha; Chaturvedi, Vishnu
Current investigations of bat White Nose Syndrome (WNS) and the causative fungus Pseudogymnoascus (Geomyces) destructans (Pd) are intensely focused on the reasons for the appearance of the disease in the Northeast and its rapid spread in the US and Canada. Urgent steps are still needed for the mitigation or control of Pd to save bats. We hypothesized that a focus on fungal community would advance the understanding of ecology and ecosystem processes that are crucial in the disease transmission cycle. This study was conducted in 2010-2011 in New York and Vermont using 90 samples from four mines and two caves situated within the epicenter of WNS. We used culture-dependent (CD) and culture-independent (CI) methods to catalogue all fungi ('mycobiome'). CD methods included fungal isolations followed by phenotypic and molecular identifications. CI methods included amplification of DNA extracted from environmental samples with universal fungal primers followed by cloning and sequencing. CD methods yielded 675 fungal isolates and CI method yielded 594 fungal environmental nucleic acid sequences (FENAS). The core mycobiome of WNS comprised of 136 operational taxonomic units (OTUs) recovered in culture and 248 OTUs recovered in clone libraries. The fungal community was diverse across the sites, although a subgroup of dominant cosmopolitan fungi was present. The frequent recovery of Pd (18% of samples positive by culture) even in the presence of dominant, cosmopolitan fungal genera suggests some level of local adaptation in WNS-afflicted habitats, while the extensive distribution of Pd (48% of samples positive by real-time PCR) suggests an active reservoir of the pathogen at these sites. These findings underscore the need for integrated disease control measures that target both bats and Pd in the hibernacula for the control of WNS.
Amaurys Dávila Martínez
Full Text Available Root rot in cocoyam (Colocasia esculenta, Xanthosoma saggitifolium is caused by various pathogens, among which are: F. sulfureum, F. solani, F. chlamydosporum, F. oxysporum, S. rolfsii, R. solani, Phoma sp.Diplodia sp., R. nigricans. Within the principal fungicides registered in Cuba for seed protection are mancozeb,captan, benomyl, tiran, carboxin + tiran, thiabendazole, guazatine and propamocarb among others, which are used against many fungi pathogen genera. In order to study the “in vitro ” chemical control effectiveness of Celest 0.25 FS and Celest Top 312 in combating these pathogens, this study was performed in the Phytopathology laboratory from the Research Institute of Tropical Root and Tuber Crops (INIVIT. The Potato Dextrose Agar (PDA medium that was poisoned at doses of 180, 300 and 500ppm with fungicides Celest 0.25 FS and Celest Top FS 312 was used. The fungal pathogens studied were: Fusarium sulfureum, Sclerotium rolfsii, Rhizoctonia solani and Phoma sp. Measurements were made on mycelial growth after 48, 72, 96, 120 and 144 hours alter planting. The best results in the application of Celest 0.25 FS is obtained with the dose of 500 ppm. Doses of 180 and 300 ppm exert little effect on these pathogens. Top Celest doses 312 FS (300 and 500 ppm, are very effective on “in vitro” control of fungal species tested, showing a limited radial 0.9 and 0.4 cm respectively as average.
Bell, Rayna C; Gata Garcia, Adriana V; Stuart, Bryan L; Zamudio, Kelly R
Amphibian chytridiomycosis is an infectious disease caused by the fungus Batrachochytrium dendrobatidis (Bd) that is implicated in the worldwide decline and extinction of amphibians. Africa has been proposed as a potential source for the global expansion of Bd, yet the distribution of Bd across the continent remains largely unexplored. Using quantitative polymerase chain reaction (qPCR), we screened for the presence of Bd in 166 adult anurans from two national parks in Gabon (Monts de Cristal and Ivindo). Bd was detected in 20 of the 42 species and was present at all three sites surveyed (two in Monts de Cristal, and one in Ivindo) with high prevalence (19.6%-36.0%). Both national parks were Bd-positive at all elevations and across habitat types, though no dead or dying frogs were encountered. To our knowledge, this study presents the first evidence of Bd in Gabon and the first record of infection for 19 of the 20 species that were Bd-positive. Documenting the distribution and virulence of Bd across Africa will be essential for understanding the dynamics of amphibian chytridiomycosis across the globe.
Taheri, Parissa; Kakooee, Tahereh
Alternaria blight is a major and destructive disease of potato worldwide. In recent years, A. tenuissima is recognized as the most prevalent species of this phytopathogenic fungus in potato fields of Asian countries, which causes high yield losses every year. Any potato cultivar with complete resistance to this disease is not recognized, so far. Therefore, screening resistance levels of potatoes and identification of plant defense mechanisms against this fungus might be important for designing novel and effective disease management strategies for controlling the disease. In this research, the role of reactive oxygen species, antioxidants, lignin and phenolics in potato basal resistance to A. tenuissima was compared in the partially resistant Ramus and susceptible Bamba cultivars. Priming O 2 - and H 2 O 2 production and enhanced activity of peroxidase (POX) and catalase (CAT) during interaction with A. tenuissima were observed in Ramus cultivar. Application of ROS generating systems and scavengers revealed critical role of O 2 - and H 2 O 2 in potato defense, which was associated with lignification and phenolics production. More OH - and lipid peroxidation in the susceptible Bamba compared to Ramus cultivar showed their negative effects on resistance. Priming the POX and CAT activity, in correlation with upregulation of the corresponding genes was observed in Ramus. The POX and CAT inhibitors increased disease progress, which was related with decreased lignification. This assay demonstrated not only POX-dependency of lignification, but also its dependence on CAT. However, POX had more importance than CAT in potato defense and in lignification. These findings highlight the function of ROS accumulation and homeostasis in potato resistance against A. tenuissima. Copyright © 2017 Elsevier GmbH. All rights reserved.
Full Text Available Biological control (biocontrol agents act on plants via numerous mechanisms, and can be used to protect plants from pathogens. Biocontrol agents can act directly as pathogen antagonists or competitors or indirectly to promote plant induced systemic resistance (ISR. Whether a biocontrol agent acts directly or indirectly depends on the specific strain and the pathosystem type. We reported previously that bacterial volatile organic compounds (VOCs are determinants for eliciting plant ISR. Emerging data suggest that bacterial VOCs also can directly inhibit fungal and plant growth. The aim of the current study was to differentiate direct and indirect mechanisms of bacterial VOC effects against Botrytis cinerea infection of Arabidopsis. Volatile emissions from Bacillus subtilis GB03 successfully protected Arabidopsis seedlings against B. cinerea. First, we investigated the direct effects of bacterial VOCs on symptom development and different phenological stages of B. cinerea including spore germination, mycelial attachment to the leaf surface, mycelial growth, and sporulation in vitro and in planta. Volatile emissions inhibited hyphal growth in a dose-dependent manner in vitro, and interfered with fungal attachment on the hydrophobic leaf surface. Second, the optimized bacterial concentration that did not directly inhibit fungal growth successfully protected Arabidopsis from fungal infection, which indicates that bacterial VOC-elicited plant ISR has a more important role in biocontrol than direct inhibition of fungal growth on Arabidopsis. We performed qRT-PCR to investigate the priming of the defense-related genes PR1, PDF1.2, and ChiB at 0, 12, 24, and 36 hours post-infection and 14 days after the start of plant exposure to bacterial VOCs. The results indicate that bacterial VOCs potentiate expression of PR1 and PDF1.2 but not ChiB, which stimulates SA- and JA-dependent signaling pathways in plant ISR and protects plants against pathogen
Full Text Available Vibrio parahaemolyticus is a well-recognized pathogen of humans. To better understand the ecology of the human-pathogenic variants of this bacterium in the environment, a study on the prevalence in bivalves of pathogenic variants (tlh + and tdh+ and/or trh+ versus a nonpathogenic one (only tlh+ as species marker for V. parahaemolyticus, was performed in two bays in Catalonia, Spain. Environmental factors that might affect dynamics of both variants of V. parahaemolyticus were taken into account. The results showed that the global prevalence of total V. parahaemolyticus found in both bays was 14.2% (207/1459. It was, however, significantly dependent on sampling point, campaign (year and bivalve species. Pathogenic variants of V. parahaemolyticus (tdh+ and/or trh+ were detected in 3.8% of the samples (56/1459, meaning that the proportion of bivalves who contained tlh gene were contaminated by pathogenic V. parahaemolyticus strains is 27.1% (56/207. Moreover, the presence of pathogenic V. parahaemolyticus (trh+ was significantly correlated with water salinity, thus the probability of finding pathogenic V. parahaemolyticus decreased 1.45 times with every salinity unit (ppt increased. Additionally, data showed that V. parahaemolyticus could establish close associations with Ruditapes spp. (P-value < 0.001, which could enhance the transmission of illness to human by pathogenic variants, when clams were eaten raw or slightly cooked.This study provides information on the abundance, ecology and characteristics of total and human-pathogenic V. parahaemolyticus variants associated with bivalves cultured in the Spanish Mediterranean Coast.
Introduction: Swine are the only known animal reservoir of Yersinia enterocolitica (YE), a human pathogen. Since YE is a fecal organism of swine, the primary goal of this study was to evaluate the prevalence, serotype, virulence plasmid (pYV)-associated characteristics, clonality, and antibiotic su...
Armijos Jaramillo, Vinicio Danilo; Vargas, Walter Alberto; Sukno, Serenella Ana; Thon, Michael R
The genus Colletotrichum contains a large number of phytopathogenic fungi that produce enormous economic losses around the world. The effect of horizontal gene transfer (HGT) has not been studied yet in these organisms. Inter-Kingdom HGT into fungal genomes has been reported in the past but knowledge about the HGT between plants and fungi is particularly limited. We describe a gene in the genome of several species of the genus Colletotrichum with a strong resemblance to subtilisins typically found in plant genomes. Subtilisins are an important group of serine proteases, widely distributed in all of the kingdoms of life. Our hypothesis is that the gene was acquired by Colletotrichum spp. through (HGT) from plants to a Colletotrichum ancestor. We provide evidence to support this hypothesis in the form of phylogenetic analyses as well as a characterization of the similarity of the subtilisin at the primary, secondary and tertiary structural levels. The remarkable level of structural conservation of Colletotrichum plant-like subtilisin (CPLS) with plant subtilisins and the differences with the rest of Colletotrichum subtilisins suggests the possibility of molecular mimicry. Our phylogenetic analysis indicates that the HGT event would have occurred approximately 150-155 million years ago, after the divergence of the Colletotrichum lineage from other fungi. Gene expression analysis shows that the gene is modulated during the infection of maize by C. graminicola suggesting that it has a role in plant disease. Furthermore, the upregulation of the CPLS coincides with the downregulation of several plant genes encoding subtilisins. Based on the known roles of subtilisins in plant pathogenic fungi and the gene expression pattern that we observed, we postulate that the CPLSs have an important role in plant infection.
Margaret V Powers-Fletcher
Full Text Available Calnexin is a membrane-bound lectin chaperone in the endoplasmic reticulum (ER that is part of a quality control system that promotes the accurate folding of glycoproteins entering the secretory pathway. We have previously shown that ER homeostasis is important for virulence of the human fungal pathogen Aspergillus fumigatus, but the contribution of calnexin has not been explored. Here, we determined the extent to which A. fumigatus relies on calnexin for growth under conditions of environmental stress and for virulence. The calnexin gene, clxA, was deleted from A. fumigatus and complemented by reconstitution with the wild type gene. Loss of clxA altered the proteolytic secretome of the fungus, but had no impact on growth rates in either minimal or complex media at 37°C. However, the ΔclxA mutant was growth impaired at temperatures above 42°C and was hypersensitive to acute ER stress caused by the reducing agent dithiothreitol. In contrast to wild type A. fumigatus, ΔclxA hyphae were unable to grow when transferred to starvation medium. In addition, depleting the medium of cations by chelation prevented ΔclxA from sustaining polarized hyphal growth, resulting in blunted hyphae with irregular morphology. Despite these abnormal stress responses, the ΔclxA mutant remained virulent in two immunologically distinct models of invasive aspergillosis. These findings demonstrate that calnexin functions are needed for growth under conditions of thermal, ER and nutrient stress, but are dispensable for surviving the stresses encountered in the host environment.
Andrea J Adams
Full Text Available Museum collections provide indispensable repositories for obtaining information about the historical presence of disease in wildlife populations. The pathogenic amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd has played a significant role in global amphibian declines, and examining preserved specimens for Bd can improve our understanding of its emergence and spread. Quantitative PCR (qPCR enables Bd detection with minimal disturbance to amphibian skin and is significantly more sensitive to detecting Bd than histology; therefore, developing effective qPCR methodologies for detecting Bd DNA in formalin-fixed specimens can provide an efficient and effective approach to examining historical Bd emergence and prevalence. Techniques for detecting Bd in museum specimens have not been evaluated for their effectiveness in control specimens that mimic the conditions of animals most likely to be encountered in museums, including those with low pathogen loads. We used American bullfrogs (Lithobates catesbeianus of known infection status to evaluate the success of qPCR to detect Bd in formalin-fixed specimens after three years of ethanol storage. Our objectives were to compare the most commonly used DNA extraction method for Bd (PrepMan, PM to Macherey-Nagel DNA FFPE (MN, test optimizations for Bd detection with PM, and provide recommendations for maximizing Bd detection. We found that successful detection is relatively high (80-90% when Bd loads before formalin fixation are high, regardless of the extraction method used; however, at lower infection levels, detection probabilities were significantly reduced. The MN DNA extraction method increased Bd detection by as much as 50% at moderate infection levels. Our results indicate that, for animals characterized by lower pathogen loads (i.e., those most commonly encountered in museum collections, current methods may underestimate the proportion of Bd-infected amphibians. Those extracting DNA from
Adams, Andrea J; LaBonte, John P; Ball, Morgan L; Richards-Hrdlicka, Kathryn L; Toothman, Mary H; Briggs, Cheryl J
Museum collections provide indispensable repositories for obtaining information about the historical presence of disease in wildlife populations. The pathogenic amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd) has played a significant role in global amphibian declines, and examining preserved specimens for Bd can improve our understanding of its emergence and spread. Quantitative PCR (qPCR) enables Bd detection with minimal disturbance to amphibian skin and is significantly more sensitive to detecting Bd than histology; therefore, developing effective qPCR methodologies for detecting Bd DNA in formalin-fixed specimens can provide an efficient and effective approach to examining historical Bd emergence and prevalence. Techniques for detecting Bd in museum specimens have not been evaluated for their effectiveness in control specimens that mimic the conditions of animals most likely to be encountered in museums, including those with low pathogen loads. We used American bullfrogs (Lithobates catesbeianus) of known infection status to evaluate the success of qPCR to detect Bd in formalin-fixed specimens after three years of ethanol storage. Our objectives were to compare the most commonly used DNA extraction method for Bd (PrepMan, PM) to Macherey-Nagel DNA FFPE (MN), test optimizations for Bd detection with PM, and provide recommendations for maximizing Bd detection. We found that successful detection is relatively high (80-90%) when Bd loads before formalin fixation are high, regardless of the extraction method used; however, at lower infection levels, detection probabilities were significantly reduced. The MN DNA extraction method increased Bd detection by as much as 50% at moderate infection levels. Our results indicate that, for animals characterized by lower pathogen loads (i.e., those most commonly encountered in museum collections), current methods may underestimate the proportion of Bd-infected amphibians. Those extracting DNA from archived museum
Lu, Tao; Yao, Bo; Zhang, Chi
Fungal pathogens cause various diseases for plant and animal hosts. Despite the extensive impact of fungi on human health and life, the threats posed by emerging fungal pathogens are poorly understood. Specifically, there exist few fungal virulence gene databases, which prevent effective bioinformatics studies on fungal pathogens. Therefore, we constructed a comprehensive online database of known fungal virulence factors, which collected 2058 pathogenic genes produced by 228 fungal strains from 85 genera. This database creates a pivotal platform capable of stimulating and facilitating further bench studies on fungal pathogens. Database URL: http://sysbio.unl.edu/DFVF/ PMID:23092926
Pelizza, S A; Elíades, L A; Saparrat, M C N; Cabello, M N; Scorsetti, A C; Lange, C E
Tropidacris collaris (Orthoptera: Romaleidae) is a large and voracious grasshopper, which, in recent years, has become a recurrent pest in increasingly extensive areas of Argentina's northern provinces. In the present work chitinase activity was measured in 59 entomopathogenic fungal isolates native to Argentina, and the relationship between enzymatic activity and fungal virulence was assessed. Isolate LPSC 1067 caused the highest mortality on T. collaris nymphs (97.7 ± 1.22%). Nine isolates caused no mortality, while the remaining 49 caused mortalities ranging from 6.6 ± 0.3% (LPSC 770) to 91.06 ± 1.51% (LPSC 906). Several isolates revealed chitinolytic capabilities on test plates, although the activities differed with respect to the ratio of the chitin-decay-halo and fungal-colony diameters. A principal component analysis indicated that isolate LPSC 1067, obtained from a long-horned grasshopper (Orthoptera: Tettigoniidae), would be a potential candidate for T. collaris biocontrol because the strain exhibited the highest mortality, a shorter median lethal time, and a high enzymatic activity and growth rate.
Fox, J Trent; Reinstein, Shelby; Jacob, Megan E; Nagaraja, T G
Niche-marketed food products are rapidly gaining market share in today's society. Consumers are willing to pay premium prices for food perceived to be safer, healthier, more nutritious, and better tasting than conventional food. This review outlines typical production practices for niche-market beef production systems in the United States and compares prevalence estimates of foodborne pathogens in animals and produce from conventional and niche-market production systems. The two main niches for food animal production are organic and natural productions. Organic and natural beef productions are becoming increasingly popular and there is high consumer demand. Two major differences between conventional beef production systems and niche-market production systems (natural and organic) are in the use of antimicrobials and growth-promoting hormones. The impacts of these production systems on foodborne pathogens in beef cattle are variable and often data are nonexistent. Studies directly comparing conventional and niche-market production systems for dairy, swine, poultry, and produce have observed that the prevalence of foodborne pathogens was seldom statistically different between production systems, but when differences were observed, prevalence was typically greater for the niche-market production systems than the conventional production system. The published literature suggests that the perception of niche-marketed food products being safer and healthier for consumers with regard to foodborne pathogens may not be justified.
Regina G. Kleespies
Full Text Available About 20,550 larvae, pupae and adults of the codling moth, Cydia pomonella L., were diagnosed for pathogens during long-term investigations (1955–2012 at the Institute for Biological Control in Darmstadt, Germany. The prevailing entomopathogens diagnosed in these studies were insect pathogenic fungi, especially Beauveria bassiana and Isaria farinosa, the microsporidium, Nosema carpocapsae, the Cydia pomonella granulovirus (CpGV, as well as mostly undetermined bacteria. While the CpGV was observed exclusively in larvae and pupae from laboratory colonies or from field experiments with this virus, entomopathogenic fungi were most frequently diagnosed in last instars in autumn and in diapausing larvae and pupae in spring. B. bassiana was identified as the major fungal pathogen, causing larval prevalences of 0.9% to 100% (mean, about 32%. During prognostic long-term studies in larvae and adults of C. pomonella, N. carpocapsae was diagnosed in codling moth populations from various locations in Germany. The mean prevalence generally ranged between 20% and 50%. Experiments revealed that the fecundity and fertility of microsporidia-infected female adults were significantly reduced compared to healthy ones. The results underpin the importance of naturally occurring microbial antagonists and represent a base for further ecological studies on developing new or additional biological and integrated control strategies.
Zimmermann, Gisbert; Huger, Alois M; Kleespies, Regina G
About 20,550 larvae, pupae and adults of the codling moth, Cydia pomonella L., were diagnosed for pathogens during long-term investigations (1955-2012) at the Institute for Biological Control in Darmstadt, Germany. The prevailing entomopathogens diagnosed in these studies were insect pathogenic fungi, especially Beauveria bassiana and Isaria farinosa, the microsporidium, Nosema carpocapsae, the Cydia pomonella granulovirus (CpGV), as well as mostly undetermined bacteria. While the CpGV was observed exclusively in larvae and pupae from laboratory colonies or from field experiments with this virus, entomopathogenic fungi were most frequently diagnosed in last instars in autumn and in diapausing larvae and pupae in spring. B. bassiana was identified as the major fungal pathogen, causing larval prevalences of 0.9% to 100% (mean, about 32%). During prognostic long-term studies in larvae and adults of C. pomonella, N. carpocapsae was diagnosed in codling moth populations from various locations in Germany. The mean prevalence generally ranged between 20% and 50%. Experiments revealed that the fecundity and fertility of microsporidia-infected female adults were significantly reduced compared to healthy ones. The results underpin the importance of naturally occurring microbial antagonists and represent a base for further ecological studies on developing new or additional biological and integrated control strategies.
Full Text Available The negative impact of long term utilization of pesticides on yields quality, as well as on the human health made scientific community to seek new ways, less expensive and environmental friendly for protecting cultivated plants against pathogens. Biological control agents of microbial origin represented by living selected strains or their metabolites are more and more frequently utilized for protecting horticultural plants intensely consumed by European population, such as strawberry. A green house experiment was designed to compare the structure of rhizospheric and phylospheric microflora of strawberry cv. Senga Sengana, sensible to Botrytis cinerea (the agent of grey mould treated with systemic and contact fungicides, as well as with four biological control preparations of microbial origin administrated on plant leaves or in the soil. The structure of fungal communities in rhizosphere and phylosphere of strawberry cv. Senga Sengana varied as a function of the nature of control agent and the method of administration. Non significant influence on soil fungal community diversity index and species number was registered after the treatment with chemical and biological control agents, but significant increments were induced in time by control agents as compared with both non-treated control and chemical pesticides. Fungal community structure from strawberry leaves was not significantly influenced by chemical and biological control agents. The most favourable influence on fungal communities registered for bio-control agents E1 and E2 due to
Gutierrez, Alejandra Concepción; Tornesello-Galván, Julieta; Manfrino, Romina Guadalupe; Hipperdinger, Marcela; Falvo, Marianel; D'Alessandro, Celeste; López Lastra, Claudia Cristina
The collection of fungal pathogens and symbionts of insects and other arthropods of the Centro de Estudios Parasitológicos y de Vectores, La Plata, Argentina, is unique because it preserves in vivo and in vitro cultures of fungal pathogens. This culture collection is open for research, teaching, consulting services, and strain deposit. It contains 421 strains belonging to 23 genera (16 Ascomycota, 4 Entomophthoromycotina, 2 Glomeromycota and 1 Oomycota), and the cultures are preserved by different methods such as cryopreservation in freezer at -20°C and -70°C, paper, distilled water and lyophilization. Fungi were isolated from insects, other arthropods, and soil (by using insect baits and selective media). Species were identified by morphological features and in a few strains by molecular taxonomy (PCR of rDNA). This collection is a reference center for species identification/certifications, research and teaching purposes, strain deposit, transference and consultancy services, and its overall goal is to preserve the fungal germplasm and ex situ diversity. Most of the strains are native of Argentina. The collection was originated in 1988 and is registered in the Latin American Federation for Culture Collections and in the World Federation of Culture Collections. Copyright © 2016 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.
Arshad, Waheed; Haq, Ihsan-ul-; Waheed, Mohammad Tahir; Mysore, Kirankumar S; Mirza, Bushra
Tomato (Solanum lycopersicum L.) is the second most important cultivated crop next to potato, worldwide. Tomato serves as an important source of antioxidants in human diet. Alternaria solani and Fusarium oxysporum cause early blight and vascular wilt of tomato, respectively, resulting in severe crop losses. The foremost objective of the present study was to generate transgenic tomato plants with rolB gene and evaluate its effect on plant morphology, nutritional contents, yield and resistance against fungal infection. Tomato cv. Rio Grande was transformed via Agrobacterium tumefaciens harbouring rolB gene of Agrobacterium rhizogenes. rolB. Biochemical analyses showed considerable improvement in nutritional quality of transgenic tomato fruits as indicated by 62% increase in lycopene content, 225% in ascorbic acid content, 58% in total phenolics and 26% in free radical scavenging activity. Furthermore, rolB gene significantly improved the defence response of leaves of transgenic plants against two pathogenic fungal strains A. solani and F. oxysporum. Contrarily, transformed plants exhibited altered morphology and reduced fruit yield. In conclusion, rolB gene from A. rhizogenes can be used to generate transgenic tomato with increased nutritional contents of fruits as well as improved foliar tolerance against fungal pathogens.
Full Text Available Tomato (Solanum lycopersicum L. is the second most important cultivated crop next to potato, worldwide. Tomato serves as an important source of antioxidants in human diet. Alternaria solani and Fusarium oxysporum cause early blight and vascular wilt of tomato, respectively, resulting in severe crop losses. The foremost objective of the present study was to generate transgenic tomato plants with rolB gene and evaluate its effect on plant morphology, nutritional contents, yield and resistance against fungal infection. Tomato cv. Rio Grande was transformed via Agrobacterium tumefaciens harbouring rolB gene of Agrobacterium rhizogenes. rolB. Biochemical analyses showed considerable improvement in nutritional quality of transgenic tomato fruits as indicated by 62% increase in lycopene content, 225% in ascorbic acid content, 58% in total phenolics and 26% in free radical scavenging activity. Furthermore, rolB gene significantly improved the defence response of leaves of transgenic plants against two pathogenic fungal strains A. solani and F. oxysporum. Contrarily, transformed plants exhibited altered morphology and reduced fruit yield. In conclusion, rolB gene from A. rhizogenes can be used to generate transgenic tomato with increased nutritional contents of fruits as well as improved foliar tolerance against fungal pathogens.
Full Text Available BACKGROUND: Effector proteins of biotrophic plant pathogenic fungi and oomycetes are delivered into host cells and play important roles in both disease development and disease resistance response. How obligate fungal pathogen effectors enter host cells is poorly understood. The Ps87 gene of Puccinia striiformis encodes a protein that is conserved in diverse fungal pathogens. Ps87 homologs from a clade containing rust fungi are predicted to be secreted. The aim of this study is to test whether Ps87 may act as an effector during Puccinia striiformis infection. METHODOLOGY/PRINCIPAL FINDINGS: Yeast signal sequence trap assay showed that the rust protein Ps87 could be secreted from yeast cells, but a homolog from Magnaporthe oryzae that was not predicted to be secreted, could not. Cell re-entry and protein uptake assays showed that a region of Ps87 containing a conserved RXLR-like motif [K/R]RLTG was confirmed to be capable of delivering oomycete effector Avr1b into soybean leaf cells and carrying GFP into soybean root cells. Mutations in the Ps87 motif (KRLTG abolished the protein translocation ability. CONCLUSIONS/SIGNIFICANCE: The results suggest that Ps87 and its secreted homologs could utilize similar protein translocation machinery as those of oomycete and other fungal pathogens. Ps87 did not show direct suppression activity on plant defense responses. These results suggest Ps87 may represent an "emerging effector" that has recently acquired the ability to enter plant cells but has not yet acquired the ability to alter host physiology.
Full Text Available The objective of this study was to investigate and summarize the levels of incidence of Salmonella spp., Listeria monocytogenes, Staphylococcus aureus and Campylobacter spp. in poultry meat commercialized in Europe. After systematic review, incidence data and study characteristics were extracted from 78 studies conducted in 21 European countries. Pooled prevalence values from 203 extracted observations were estimated from random-effects meta-analysis models adjusted by pathogen, poultry type, sampling stage, cold preservation type, meat cutting type and packaging status. The results suggest that S. aureus is the main pathogen detected in poultry meat (38.5%; 95% CI: 25.4–53.4, followed by Campylobacter spp. (33.3%; 95% CI: 22.3–46.4%, while L. monocytogenes and Salmonella spp. present lower prevalence (19.3%; 95% CI: 14.4–25.3% and 7.10%; 95% CI: 4.60–10.8%, respectively. Despite the differences in prevalence, all pathogens were found in chicken and other poultry meats, at both end-processing step and retail level, in packed and unpacked products and in several meat cutting types. Prevalence data on cold preservation products also revealed that chilling and freezing can reduce the proliferation of pathogens but might not be able to inactivate them. The results of this meta-analysis highlight that further risk management strategies are needed to reduce pathogen incidence in poultry meat throughout the entire food chain across Europe, in particular for S. aureus and Campylobacter spp.
Larissa V.G. Longo
Full Text Available We identified non-covalently linked cell wall proteins from Paracoccidioides brasiliensis yeasts and mycelia, with focus on the yeast pathogenic phase, and correlated them with reported fungal extracellular vesicle proteins. We studied isolates Pb3 and Pb18, which evoke distinct patterns of experimental paracoccidioidomycosis and represent two phylogenetic groups. Proteins were extracted mildly with dithiothreitol, trypsinized, and peptides analyzed by liquid chromatography coupled to high-resolution mass spectrometry. Among 132 yeast-exclusive sequences, 92 were Pb18-exclusive. About 80% of total proteins were classified as secretory, mostly showing non-conventional signals. Extracellular vesicular transportation could be involved, since 60% had orthologs reported in fungal extracellular vesicles.
Montone, Kathleen T; Guarner, Jeannette
Fungal infections are a frequent occurrence in medical practice due to increasing numbers of immunosuppressed patients. New antifungal medications have been developed and it has become evident that different fungi require different treatments as some are intrinsically resistant to these drugs. Thus, it is imperative that pathologists recognize the limitations of histopathologic diagnosis regarding speciation of fungal infections and advocate for the use of different techniques that can help define the genus and species of the fungus present in the specimen they are studying. In this review we present the use of in situ hybridization as an important adjunct for the diagnosis of fungal diseases, the different techniques that have been used for fungal identification, and the limitations that these techniques have.
Wang, Chenggang; Ding, Yezhang; Yao, Jin; Zhang, Yanping; Sun, Yijun; Colee, James; Mou, Zhonglin
The evolutionarily conserved Elongator complex functions in diverse biological processes including salicylic acid-mediated immune response. However, how Elongator functions in jasmonic acid (JA)/ethylene (ET)-mediated defense is unknown. Here, we show that Elongator is required for full induction of the JA/ET defense pathway marker gene PLANT DEFENSIN1.2 (PDF1.2) and for resistance to the necrotrophic fungal pathogens Botrytis cinerea and Alternaria brassicicola. A loss-of-function mutation in the Arabidopsis Elongator subunit 2 (ELP2) alters B. cinerea-induced transcriptome reprogramming. Interestingly, in elp2, expression of WRKY33, OCTADECANOID-RESPONSIVE ARABIDOPSIS AP2/ERF59 (ORA59), and PDF1.2 is inhibited, whereas transcription of MYC2 and its target genes is enhanced. However, overexpression of WRKY33 or ORA59 and mutation of MYC2 fail to restore PDF1.2 expression and B. cinerea resistance in elp2, suggesting that ELP2 is required for induction of not only WRKY33 and ORA59 but also PDF1.2. Moreover, elp2 is as susceptible as coronatine-insensitive1 (coi1) and ethylene-insensitive2 (ein2) to B. cinerea, indicating that ELP2 is an important player in B. cinerea resistance. Further analysis of the lesion sizes on the double mutants elp2 coi1 and elp2 ein2 and the corresponding single mutants revealed that the function of ELP2 overlaps with COI1 and is additive to EIN2 for B. cinerea resistance. Finally, basal histone acetylation levels in the coding regions of WRKY33, ORA59, and PDF1.2 are reduced in elp2 and a functional ELP2-GFP fusion protein binds to the chromatin of these genes, suggesting that constitutive ELP2-mediated histone acetylation may be required for full activation of the WRKY33/ORA59/PDF1.2 transcriptional cascade. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.
Zhao, Yanqing; Liu, Hui; Zhao, Xuanduo; Gao, Yang; Zhang, Miaotao; Chen, Dekun
Subclinical mastitis, a costly disease for the dairy industry, is usually caused by intramammary bacterial infection. The aim of this study was to investigate the prevalence of and pathogens involved in subclinical mastitis in dairy goats in China. A total of 683 dairy goats in the main breeding areas of China were selected, and milk samples were collected. Out of these, 313 (45.82 %) goats were detected distinct or strong positive for subclinical mastitis by using California mastitis test. Among these positive goats, 209 milk samples were used to identify the causing agents by a multiplex PCR assay, and results were listed as follows: coagulase-negative staphylococci (59.52 %), Staphylococcus aureus (15.24 %), Escherichia coli (11.43 %), and Streptococcus spp. (10.95 %). In conclusion, subclinical mastitis is a highly prevalent disease in dairy goats in China, and coagulase-negative staphylococci are the predominant pathogens.
Tickell, Kirkby D; Pavlinac, Patricia B; John-Stewart, Grace C; Denno, Donna M; Richardson, Barbra A; Naulikha, Jaqueline M; Kirera, Ronald K; Swierczewski, Brett E; Singa, Benson O; Walson, Judd L
Children with acute and chronic malnutrition are at increased risk of morbidity and mortality following a diarrheal episode. To compare diarrheal disease severity and pathogen prevalence among children with and without acute and chronic malnutrition, we conducted a cross-sectional study of human immunodeficiency virus-uninfected Kenyan children aged 6-59 months, who presented with acute diarrhea. Children underwent clinical and anthropometric assessments and provided stool for bacterial and protozoal pathogen detection. Clinical and microbiological features were compared using log binomial regression among children with and without wasting (mid-upper arm circumference ≤ 125 mm) or stunting (height-for-age z score ≤ -2). Among 1,363 children, 7.0% were wasted and 16.9% were stunted. After adjustment for potential confounders, children with wasting were more likely than nonwasted children to present with at least one Integrated Management of Childhood Illness danger sign (adjusted prevalence ratio [aPR]: 1.3, 95% confidence interval [CI]: 1.0 to 1.5, P = 0.05), severe dehydration (aPR: 2.4, 95% CI: 1.5 to 3.8, P < 0.01), and enteroaggregative Escherichia coli recovered from their stool (aPR: 1.8, 1.1-2.8, P = 0.02). There were no differences in the prevalence of other pathogens by wasting status after confounder adjustment. Stunting was not associated with clinical severity or the presence of specific pathogens. Wasted children with diarrhea presented with more severe disease than children without malnutrition which may be explained by a delay in care-seeking or diminished immune response to infection. Combating social determinants and host risk factors associated with severe disease, rather than specific pathogens, may reduce the disparities in poor diarrhea-associated outcomes experienced by malnourished children.
Chantziaras, Ilias; Dewulf, Jeroen; Boyen, Filip; Callens, Benedicte; Butaye, Patrick
In this article, detailed studies on antimicrobial resistance to commensal E. coli (in pigs, meat-producing bovines, broiler chickens and veal calves) and pathogenic E. coli (in pigs and bovines) in Belgium are presented for 2011. Broiler chicken and veal calf isolates of commensal E. coli demonstrated higher antimicrobial resistance prevalence than isolates from pigs and bovines. Fifty percent of E. coli isolates from broiler chickens were resistant to at least five antimicrobials, whereas s...
Lim, Wai Ho; Lien, Reyin; Huang, Yhu-Chering; Chiang, Ming-Chou; Fu, Ren-Huei; Chu, Shih-Ming; Hsu, Jen-Fu; Yang, Peng-Hong
Neonatal sepsis contributes to great mortality and morbidity among very-low-birth-weight (VLBW) infants. Prevalence and pathogen distribution of sepsis in the neonatal intensive care units (NICUs) vary with time and geographic location. Such information serves as a guide for selection of empirical antibiotics coverage. This is a case series study performed by retrospective chart review of VLBW infants (birth body weight, BBW, <1500 g) in a medical center during a 5-year period from January 2005 to December 2009. Episodes of positive blood cultures, pathogen distribution and related clinical manifestations were described. A total of 158 episodes of sepsis were identified from 1042 VLBW infants. Sepsis rate was 152 per 1000 live births. The vast majority of infections (60.7%) were caused by Gram-positive organisms [G(+)], and overall Coagulase-negative staphylococci (CoNS) (52.5%) were the most common pathogen identified. Prevalence for early-onset sepsis (EOS) was 1% and for late-onset sepsis (LOS) was 14.2%. Infants with EOS had a much higher case fatality rate than LOS (40% vs. 4.7%). Escherichia coli (40%) were the leading pathogen of EOS while CoNS (54.7%) was the leading pathogens of LOS. Overall, apnea and/or bradycardia and/or cyanosis (65.8%), poor activity (48.7%), and increased respiratory effort (43.0%) were the most common presenting features of sepsis. Unlike term infants, Gram-negative organism and E coli were the leading pathogen of EOS among VLBW infants. Judicious and timely use of antibiotic therapy is crucial in the care of VLBW infants. Copyright © 2012. Published by Elsevier B.V.
Gill, Upinder S; Sun, Liang; Rustgi, Sachin; Tang, Yuhong; von Wettstein, Diter; Mysore, Kirankumar S
Phosphite (Phi) is used commercially to manage diseases mainly caused by oomycetes, primarily due to its low cost compared with other fungicides and its persistent control of oomycetous pathogens. We explored the use of Phi in controlling the fungal pathogens Puccinia emaculata and Phakopsora pachyrhizi, the causal agents of switchgrass rust and Asian soybean rust, respectively. Phi primes host defenses and efficiently inhibits the growth of P. emaculata, P. pachyrhizi and several other fungal pathogens tested. To understand these Phi-mediated effects, a detailed molecular analysis was undertaken in both the host and the pathogen. Transcriptomic studies in switchgrass revealed that Phi activates plant defense signaling as early as 1 h after application by increasing the expression of several cytoplasmic and membrane receptor-like kinases and defense-related genes within 24 h of application. Unlike in oomycetes, RNA sequencing of P. emaculata and P. pachyrhizi did not exhibit Phi-mediated retardation of cell wall biosynthesis. The genes with reduced expression in either or both rust fungi belonged to functional categories such as ribosomal protein, actin, RNA-dependent RNA polymerase, and aldehyde dehydrogenase. A few P. emaculata genes that had reduced expression upon Phi treatment were further characterized. Application of double-stranded RNAs specific to P. emaculata genes encoding glutamate N-acetyltransferase and cystathionine gamma-synthase to switchgrass leaves resulted in reduced disease severity upon P. emaculata inoculation, suggesting their role in pathogen survival and/or pathogenesis. © 2018 The Authors The Plant Journal © 2018 John Wiley & Sons Ltd.
Watts, Dominique E; Benson, Anna-Marie
We collected blood samples from wolves ( Canis lupus ) on the Alaska Peninsula, southwest Alaska, US, 2006-11 and tested sera for antibodies to canine adenovirus (CAV), canine coronavirus (CCV), canine distemper virus (CDV), canine herpesvirus (CHV), canine parainfluenza (CPI), canine parvovirus (CPV), Neospora caninum , and Toxoplasma gondii . Detected antibody prevalence was 90% for CAV, 28% for CCV, 12% for CDV, 93% for CHV, 0% for CPI, 20% for CPV, 0% for N. caninum, and 86% for T. gondii . Prevalence of CCV antibodies suggested a seasonal pattern with higher prevalence during spring (43%) than in fall (11%). Prevalence of CCV antibodies also declined during the 6-yr study with high prevalence during spring 2006-08 (80%, n=24) and low prevalence during spring 2009-11 (4%, n=24). Prevalence of N. caninum and T. gondii antibodies were highly variable in the study area during 2006-11. Results suggested that some pathogens might be enzootic on the Alaska Peninsula (e.g., CAV and CHV) while others may be epizootic (e.g., CCV, N. caninum , T. gondii ).
Full Text Available The increased incidence of systemic fungal infections in the past two decades has been overwhelming. Earlier, it was pathogenic dimorphic fungi, which were known to cause systemic infections. However, starting from the 1960s, opportunistic fungi started causing more number of infections, especially in the immunocompromised host. More recently, newer and less common fungal agents are being increasingly associated with infection in immunosuppressed hosts. Amongst dimorphic fungi, infections due to Histoplasma capsulatum and Penicillium marneffei are increasingly reported in patients with AIDS in India. H. capsulatum is found country wide, but P. marneffei remains restricted to Manipur state. Although both varieties of C. neoformans , C. neoformans var. neoformans (serotypes A & D, and C. neoformans var. gattii (serotypes B & C are reported in India, most of the cases reported are of serotype A. Increased incidence of cryptococcosis is reported from all centers with the emergence of AIDS. Systemic infection due to species under Candida , Aspergillus and zygomycetes is widely prevalent in nosocomial setting, and outbreaks due to unusual fungi are reported occasionally from tertiary care centers. This global change in systemic fungal infections has emphasized the need to develop good diagnostic mycology laboratories in this country and to recognize this increasingly large group of potential fungal pathogens.
Wang, Ya Jing; Qin, Yun; Guix Vallverdú, Roger; Maldonado García, Jaime; Sun, Wei; Li, Shengli; Cao, Zhijun
The objectives of this study were to estimate the herd prevalence of major mastitis pathogens in bulk tank milk (BTM) in China dairy herds, to determine the relationship between the presence of mastitis pathogens and bulk tank milk somatic cell counts (BTSCC), and to investigate the impact of different dairy cattle farming modes and region on bacterial species. BTM samples collected from 894 dairy herds in China were examined for the presence of mastitis pathogens. The Flinders Technology Associates (FTA) cards were used for BTM sample collection, storage, and transportation and bacterial DNA amplification by real-time PCR. Among contagious pathogens, Staphylococcus aureus, Streptococcus agalactiae, and Streptococcus dysgalactiae were detected in 50.1, 92.2, and 72.3% of the 894 BTM samples, respectively. Among environmental pathogens, E. coli, Streptococcus uberis, Enterococcus spp., Klebsiella spp., Serratia marcescens, Corynebacterium bovis, and Arcanobacterium pyogenes were detected in 28.6, 8.9, 35.7, 20.0, 1.3, 17.0, and 67.2% of the BTM samples, respectively. Staphylococcal β-lactamase gene was detected in 61.7% of the BTM samples. The presence of Staphylococcus aureus and Arcanobacterium pyogenes were significantly associated with high BTSCC, respectively. Significant differences were found in presence of Staphylococcus aureus, Streptococcus agalactiae, and Streptococcus dysgalactiae in BTM sampled from the small household farms, dairy-farming communities, and large-scaled dairy farms. There were significant differences in the presence of Streptococcus agalactiae, Streptococcus dysgalactiae, Arcanobacterium pyogenes, staphylococcal β-lactamase gene, Staphylococcus spp., Klebsiella spp., Enterococcus spp., and Streptococcus uberis in BTM among Inner Mongolia, Heilongjiang, and Hebei province. In conclusion, contagious mammary pathogens are predominated among pathogens in BTM samples in China. PMID:27187065
Paudyal, Narayan; Anihouvi, Victor; Hounhouigan, Joseph; Matsheka, Maitshwarelo Ignatius; Sekwati-Monang, Bonno; Amoa-Awua, Wisdom; Atter, Amy; Ackah, Nina Bernice; Mbugua, Samuel; Asagbra, Agnes; Abdelgadir, Warda; Nakavuma, Jesca; Jakobsen, Mogens; Fang, Weihuan
Food safety information in the African region is insufficient and fragmented due to lack of surveillance, documentation and reporting, thereby resulting in inefficient utilization of resources, duplication of activities, and lack of synergy among the countries of the region. This paper reviews the prevalence of foodborne pathogens in seven African countries (Benin, Botswana, Ghana, Kenya, Nigeria, Sudan and Uganda) from papers in regional or international journals published between January 2000 and December 2015. One hundred and sixteen publications that dealt with food microbiology were reviewed for general analysis, while 66 papers on contamination of pathogenic bacteria were used for meta-analysis of prevalence. The food items were split into two categories: raw foods and ready-to-eat (RTE) foods (including street food and beverages) for meta-analysis. Majority of the reviewed studies (67.2%, 78/116) dealt with food of animal origin: 38.8% for meat and eggs, 17.2% for dairy products and 11.2% for aquatic products. Only 8.6% examined foods of plant origin (fruits and vegetables). The remaining 24.1% was the composite RTE food and beverages. Enterobacteriaceae, Escherichia coli, Salmonella, Staphylococcus aureus and Listeria monocytogenes were the most frequently reported organisms in those studies. Although the data were highly heterogeneous, a striking feature is high prevalence of the major pathogens in RTE foods, almost as high as in raw foods. E. coli averaged at 37.6% in raw foods and 31.6% in RTE foods. The corresponding prevalence for Salmonella was 19.9% vs 21.7%; S. aureus, 27.8% vs 25.1% and L. monocytogenes, 19.5% vs 6.7%. The average prevalence of foodborne pathogens in these countries was 34.2% (29.0-39.3%). Differences in food types as well as non-uniform protocols for sampling and identification might have contributed to high heterogeneity (I 2 >97%) although some high prevalence data could be factual with extensive varieties of raw and RTE foods
Full Text Available Biological activity of the iridoid glycosides extract from Linaria genistifolia (L. Mill. has been investigated, namely its influence on the resistance of the winter wheat Odesschi 51 plant to the caused by the Fusarium oxysporum and Helminthosporium avenae pathogenic fungi root rot. Our results indicate that summary iridoid glycosides from this plant, containing four major known compounds: 5-O-allosylantirrinoside, antirrinoside, linarioside and 6-β-hidroxiantirride, can be successfully employed in biological control of the afore-mentioned wheat pathogens: it stimulates wheat grains germination and embryonic root growth in conditions of fungal infection. 1H and 13C NMR characteristics of 5-O-allosylantirrinoside in Py-d5 are for the first time presented. Structures of two conformers of 5-O-allosylantirrinoside in D2O and Py-d5 solutions are proposed, based on the experimental NMR evidence and molecular modelling studies.
Dan, Sorin Daniel; Tăbăran, Alexandra; Mihaiu, Liora; Mihaiu, Marian
The occurrence of pathogenic strains in poultry meat is of growing concern in Romania. Another problem found on a global level is the continuous increase of antimicrobial resistance in bacteria isolated from food. This study aimed to evaluate the prevalence of pathogenic bacteria in poultry carcasses obtained in Romania in 2012-2013 and to reveal the most prevalent patterns of antimicrobial resistance in the isolated strains. A total of 144 broiler chicken carcasses were evaluated according to classical microbiological methods. The DNA was extracted from the bacterial colonies and the resistance genes were identified by PCR. In 2012, 47.2% of the samples revealed at least one of the following bacteria: Campylobacter jejuni (9.72%; n = 7), Salmonella enterica serotype Enteritidis (4.17%; n = 3), Listeria monocytogenes (15.28%; n = 11), and Escherichia coli (16.67%; n = 12). In 2013, the number of positive samples of pathogenic bacteria decreased, although Campylobacter jejuni was isolated in a higher percentage (20.8% vs. 9.72%). The percentage of multidrug-resistant (MDR) bacteria was high (23%); the most prevalent pattern included resistance to tetracycline, sulfonamides, and quinolones/fluoroquinolones. All the resistant Salmonella and E. coli strains were tested for the presence of characteristic resistance genes (Kn, bla(TEM), tetA, tetB, tetG, DfrIa, aadA1a, Sul) and revealed that these isolates represent an important reservoir in the spread of this phenomenon. Our findings suggest that Romania urgently needs an integrated surveillance system within the entire chain, for drug-resistant pathogens isolated from poultry meat.
Deyholos Michael K
Full Text Available Abstract Background Members of plant WRKY transcription factor families are widely implicated in defense responses and various other physiological processes. For canola (Brassica napus L., no WRKY genes have been described in detail. Because of the economic importance of this crop, and its evolutionary relationship to Arabidopsis thaliana, we sought to characterize a subset of canola WRKY genes in the context of pathogen and hormone responses. Results In this study, we identified 46 WRKY genes from canola by mining the expressed sequence tag (EST database and cloned cDNA sequences of 38 BnWRKYs. A phylogenetic tree was constructed using the conserved WRKY domain amino acid sequences, which demonstrated that BnWRKYs can be divided into three major groups. We further compared BnWRKYs to the 72 WRKY genes from Arabidopsis and 91 WRKY from rice, and we identified 46 presumptive orthologs of AtWRKY genes. We examined the subcellular localization of four BnWRKY proteins using green fluorescent protein (GFP and we observed the fluorescent green signals in the nucleus only. The responses of 16 selected BnWRKY genes to two fungal pathogens, Sclerotinia sclerotiorum and Alternaria brassicae, were analyzed by quantitative real time-PCR (qRT-PCR. Transcript abundance of 13 BnWRKY genes changed significantly following pathogen challenge: transcripts of 10 WRKYs increased in abundance, two WRKY transcripts decreased after infection, and one decreased at 12 h post-infection but increased later on (72 h. We also observed that transcript abundance of 13/16 BnWRKY genes was responsive to one or more hormones, including abscisic acid (ABA, and cytokinin (6-benzylaminopurine, BAP and the defense signaling molecules jasmonic acid (JA, salicylic acid (SA, and ethylene (ET. We compared these transcript expression patterns to those previously described for presumptive orthologs of these genes in Arabidopsis and rice, and observed both similarities and differences in
Shi, Gongjun; Zhang, Zengcui; Friesen, Timothy L.; Raats, Dina; Fahima, Tzion; Brueggeman, Robert S.; Lu, Shunwen; Trick, Harold N.; Liu, Zhaohui; Chao, Wun; Frenkel, Zeev; Xu, Steven S.; Rasmussen, Jack B.; Faris, Justin D.
Necrotrophic pathogens live and feed on dying tissue, but their interactions with plants are not well understood compared to biotrophic pathogens. The wheat Snn1 gene confers susceptibility to strains of the necrotrophic pathogen Parastagonospora nodorum that produce the SnTox1 protein. We report the positional cloning of Snn1, a member of the wall-associated kinase class of receptors, which are known to drive pathways for biotrophic pathogen resistance. Recognition of SnTox1 by Snn1 activates programmed cell death, which allows this necrotroph to gain nutrients and sporulate. These results demonstrate that necrotrophic pathogens such as P. nodorum hijack host molecular pathways that are typically involved in resistance to biotrophic pathogens, revealing the complex nature of susceptibility and resistance in necrotrophic and biotrophic pathogen interactions with plants. PMID:27819043
Full Text Available Bumblebees provide pollination services not only to wildflowers but also to economically important crops. In the context of the global decline of pollinators, there is an increasing interest in determining the pathogen diversity of bumblebee species. In this work, wild bumblebees of the species Bombus terrestris and Bombus pascuorum from northern and southern Spain were molecularly screened to detect and estimate prevalence of pathogens. One third of bumblebees were infected: while viruses only infected B. pascuorum, B. terrestris was infected by Apicystis bombi, Crithidia bombi and Nosema bombi. Ecological differences between host species might affect the success of the pathogens biological cycle and consequently infection prevalence. Furthermore, sex of the bumblebees (workers or males, sampling area (north or south and altitude were important predictors of pathogen prevalence. Understanding how these factors affect pathogens distribution is essential for future conservation of bumblebee wild populations.
He, Xiaoling; Miyasaka, Susan C; Fitch, Maureen M M; Moore, Paul H; Zhu, Yun J
Taro (Colocasia esculenta) is one of the most important crops in the Pacific Islands, however, taro yields have been declining in Hawaii over the past 30 years partly due to diseases caused by oomycete and fungal pathogens. In this study, an efficient Agrobacterium tumefaciens-mediated transformation method for taro is first reported. In total, approximately 200 pieces (8 g) of embryogenic calluses were infected with the super-virulent A. tumefaciens strain EHA105 harboring the plant transformation plasmid pBI121/ricchi11 that contains the rice chitinase gene ricchi11. The presence and expression of the transgene ricchi11 in six independent transgenic lines was confirmed using polymerase chain reaction (PCR) and reverse transcription-PCR (RT-PCR). Southern blot analysis of the six independent lines indicated that three out of six (50%) had integrated a single copy of the transgene, and the other three lines had two or three copies of the transgene. Compared to the particle bombardment transformation of taro method, which was used in the previous studies, the Agrobacterium-mediated transformation method obtained 43-fold higher transformation efficiency. In addition, these six transgenic lines via Agrobacterium may be more effective for transgene expression as a result of single-copy or low-copy insertion of the transgene than the single line with multiple copies of the transgene via particle bombardment. In a laboratory bioassay, all six transgenic lines exhibited increased tolerance to the fungal pathogen Sclerotium rolfsii, ranging from 42 to 63% reduction in lesion expansion.
Full Text Available Abstract Background Puccinia striiformis f.sp. tritici (PST, an obligate fungal pathogen causing wheat yellow/stripe rust, a serious disease, has been used to understand the evolution of crop pathogen using molecular markers. However, numerous questions regarding its evolutionary history and recent migration routes still remains to be addressed, which need the genotyping of a large number of isolates, a process that is limited by both DNA extraction and genotyping methods. To address the two issues, we developed here a method for direct DNA extraction from infected leaves combined with optimized SSR multiplexing. Findings We report here an efficient protocol for direct fungal DNA extraction from infected leaves, avoiding the costly and time consuming step of spore multiplication. The genotyping strategy we propose, amplified a total of 20 SSRs in three Multiplex PCR reactions, which were highly polymorphic and were able to differentiate different PST populations with high efficiency and accuracy. Conclusion These two developments enabled a genotyping strategy that could contribute to the development of molecular epidemiology of yellow rust disease, both at a regional or worldwide scale.
Zihalirwa Kulimushi, Parent; Argüelles Arias, Anthony; Franzil, Laurent; Steels, Sébastien; Ongena, Marc
Most isolates belonging to the Bacillus amyloliquefaciens subsp. plantarum clade retain the potential to produce a vast array of structurally diverse antimicrobial compounds that largely contribute to their efficacy as biocontrol agents against numerous plant fungal pathogens. In that context, the role of cyclic lipopeptides (CLPs) has been well-documented but still little is known about the impact of interactions with other soil-inhabiting microbes on the expression of these molecules. In this work, we wanted to investigate the antagonistic activity developed by this bacterium against Rhizomucor variabilis , a pathogen isolated from diseased maize cobs in Democratic Republic of Congo. Our data show that fengycins are the major compounds involved in the inhibitory activity but also that production of this type of CLP is significantly upregulated when co-cultured with the fungus compared to pure cultures. B. amyloliquefaciens is thus able to perceive fungal molecules that are emitted and, as a response, up-regulates the biosynthesis of some specific components of its antimicrobial arsenal.
Bartelt, Luther A; Platts-Mills, James A
Giardia is a common intestinal parasite worldwide, and infection can be associated with clear and sometimes persistent symptomatology. However, in children in high-prevalence settings, it is not associated with or is perhaps even protective against acute diarrhea, and the association with long-term outcomes has been difficult to discern. Recent studies have made progress in helping us disentangle this apparent paradox. First, prospective, well-characterized cohort studies have added to the data on the association between Giardia and diarrhea in these settings and have further characterized associations between Giardia infection and nutrition, gut function, and growth. Second, animal models have further characterized the host response to Giardia and helped elucidate mechanisms by which Giardia could impair child development. Finally, new work has shed light on the heterogeneity of human Giardia strains, which may both explain discrepant findings in the literature and help guide higher-resolution analyses of this pathogen in the future. The true clinical impact of endemic pediatric giardiasis remains unclear, but recent prospective studies have confirmed a high prevalence of persistent, subclinical Giardia infections and associated growth shortfalls. Integrating how nutritional, microbial, metabolic, and pathogen-strain variables influence these outcomes could sharpen delineations between pathogenic and potentially beneficial attributes of this enigmatic parasite.
Bartelt, Luther A.
Purpose of review Giardia is a common intestinal parasite worldwide, and infection can be associated with clear and sometimes persistent symptomatology. However, in children in high prevalence settings, it is not associated with or is perhaps even protective against acute diarrhea, and the association with long-term outcomes has been difficult to discern. Recent findings Recent studies have made progress in helping us disentangle this apparent paradox. First, prospective, well-characterized cohort studies have added to the data on the association between Giardia and diarrhea in these settings and have further characterized associations between Giardia infection and nutrition, gut function, and growth. Second, animal models have further characterized the host response to Giardia and helped elucidate mechanisms by which Giardia could impair child development. Finally, new work has shed light on the heterogeneity of human Giardia strains, which may both explain discrepant findings in the literature and help guide higher-resolution analyses of this pathogen in the future. Summary The true clinical impact of endemic pediatric giardiasis remains unclear, but recent prospective studies have confirmed a high prevalence of persistent, subclinical Giardia infections and associated growth shortfalls. Integrating how nutritional, microbial, metabolic, and pathogen-strain variables influence these outcomes could sharpen delineations between pathogenic and potentially beneficial attributes of this enigmatic parasite. PMID:27479025
Shahzaman, S.; Haq, I.U.; Mukhtar, T.; Naeem, M.
Plant growth promoting rhizobacteria (PGPR), are associated with roots, found in the rhizosphere and can directly or indirectly enhance the plant growth. In this study soil was collected from rhizosphere of chickpea fields of different areas of Rawalpindi division of Pakistan. PGPR were isolated, screened and characterized. Eight isolates of rhizobacteria (RHA, RPG, RFJ, RC, RTR, RT and RK) were isolated from Rawalpindi division and were characterized. The antagonistic activity of these PGPR isolates against root infecting fungi (Fusarium oxysporum and Verticillium spp.,) was done and production of indole acetic acid (IAA), siderophore and P-solubilization was evaluated. The isolates RHA, RPG, RFJ, RC, RRD and RT were found to be positive in producing siderophore, IAA and P-solubilization. Furthermore, most of the isolates showed antifungal activity against Fusarium oxysporum, and Verticillium spp. The rhizobacterial isolates RHA, RPG, RFJ, RC, RRD, RTR, RT and RK were used as bio-inoculants that might be beneficial for chickpea cultivation as the rhizobacterial isolates possessed the plant growth promoting characters i.e. siderophore, IAA production, phosphate solubilization. In in vitro tests, Pseudomonas sp. and Bacillus spp. inhibited the mycelial growth of the fungal root pathogens. The isolates (RHA and RPG) also significantly increased (60-70%) seed germination, shoot length, root length of the chickpea. The incidence of fungi was reduced by the colonization of RHA and RPG which enhanced the seedling vigor index and seed germination. The observations revealed that isolates RHA and RPG is quite effective to reduce the fungal root infection in greenhouse, and also increases seed yields significantly. These rhizobacterial isolates appear to be efficient yield increasing as well as effective biocontrol agent against fungal root pathogen. (author)
Hanada, Kazuomi; Miyokawa, Naoyuki; Sano, Ayako; Igarashi, Sho; Yoshida, Akitoshi
A 76-year-old woman with a history of penetrating keratoplasty had cacosmia associated with dacryocystitis. Two species of yeast-like fungi were isolated from the contents of her lacrimal sac. Each cultured fungus had a unique, distinctive odor. Althogh treated with an oral antifungal agent and washing of the nasolacrimal duct, the cacosmia was not improved. The continuous dacryocystitis with cacosmia was treated by dacryocystectomy. Two yeast-like fungi were again isolated from the contents of the lacrimal sac. Pathological examination confirmed a diagnosis of fungal dacryocystitis based on the fungal hyphae observed on the excised lacrimal sac wall. The cacosmia promptly disappeared. The fungi isolated from the contents of lacrimal sac were identified by DNA sequencing as Wickerhamomyces anamalus (Pichia anomala-Candida pelliculosa) and Galactomyces geotrichum (Geotrichum candidum). The cause of cacosmia in the present case was fungal dacryocystitis. Antibiotic eye drops and steroid eye drops for the treatment of penetrating keratoplasty can cause atypical fungal presentation in the inconsistently treated lacrimal system and can induce dacryocystitis. Careful usage and consideration is necessary in the long-term use of antibiotics and steroids following corneal transplantation.
Firew Kassa Esho
Full Text Available The production and consumption of domestic natural cheese in Japan is increasing year by year. More than ninety percent of domestic natural cheese is produced in Hokkaido region of Japan, while information on its quality and safety related to foodborne pathogens is limited. To assess the microbiological safety of domestic natural cheese, a total of 126 natural cheese samples produced in Hokkaido were collected from December, 2012, to July, 2013. In addition to standard plate count (SPC and coliform counts, the prevalence study of three pathogens (Listeria monocytogenes, pathogenic Escherichia coli, and Salmonella spp. was performed on each sample. Real-time PCR and matrix-assisted laser desorption-ionization time-of-flight mass spectrometer methods were employed for identification of presumptive pathogens. Coliform was detected in 25 samples (19.8% with a minimum of 25 cfu/g and a maximum of more than 3.0 × 106 cfu/g. Salmonella spp. and L. monocytogenes were not isolated from any of the samples. Only one sample (0.80% showed positive PCR amplification for ipaH gene suggesting possible contamination of enteroinvasive E. coli or Shigella in this product. Overall results indicate that natural cheeses produced in Hokkaido region were satisfactory microbiological quality according to existing international standards.
Helliwell, Emily E; Wang, Qin; Yang, Yinong
Rice blast (Magnaporthe oryzae) and sheath blight (Rhizoctonia solani) are the two most devastating diseases of rice (Oryza sativa), and have severe impacts on crop yield and grain quality. Recent evidence suggests that ethylene (ET) may play a more prominent role than salicylic acid and jasmonic acid in mediating rice disease resistance. In this study, we attempt to genetically manipulate endogenous ET levels in rice for enhancing resistance to rice blast and sheath blight diseases. Transgenic lines with inducible production of ET were generated by expressing the rice ACS2 (1-aminocyclopropane-1-carboxylic acid synthase, a key enzyme of ET biosynthesis) transgene under control of a strong pathogen-inducible promoter. In comparison with the wild-type plant, the OsACS2-overexpression lines showed significantly increased levels of the OsACS2 transcripts, endogenous ET and defence gene expression, especially in response to pathogen infection. More importantly, the transgenic lines exhibited increased resistance to a field isolate of R. solani, as well as different races of M. oryzae. Assessment of the growth rate, generational time and seed production revealed little or no differences between wild type and transgenic lines. These results suggest that pathogen-inducible production of ET in transgenic rice can enhance resistance to necrotrophic and hemibiotrophic fungal pathogens without negatively impacting crop productivity. © 2012 The Authors Plant Biotechnology Journal © 2012 Society for Experimental Biology, Association of Applied Biologists and Blackwell Publishing Ltd.
Full Text Available Enteric Campylobacter spp. bacteria are human pathogens that frequently contaminate poultry flocks. Consumption of products from poultry origin may then lead to acute bacterial enteritis called campylobacteriosis of which prevalence is increasing for about ten years in Europe. This review summarizes Campylobacter epidemiological data, risk factors for contamination in poultry flocks and conceivable strategies to control this pathogen.
Lievens, B.; Brouwer, M.; Vanachter, A.C.R.C.; Cammue, B.P.A.; Thomma, B.P.H.J.
Although new, rapid detection and identification technologies are becoming available more and more for various plant pathogens, pathogen quantification remains one of the main challenges in the disease management of many crops. Currently, real-time polymerase chain reaction (PCR) is the most
Full Text Available Abstract Background Filamentous fungi are potent biomass degraders due to their ability to thrive in ligno(hemicellulose-rich environments. During the last decade, fungal genome sequencing initiatives have yielded abundant information on the genes that are putatively involved in lignocellulose degradation. At present, additional experimental studies are essential to provide insights into the fungal secreted enzymatic pools involved in lignocellulose degradation. Results In this study, we performed a wide analysis of 20 filamentous fungi for which genomic data are available to investigate their biomass-hydrolysis potential. A comparison of fungal genomes and secretomes using enzyme activity profiling revealed discrepancies in carbohydrate active enzymes (CAZymes sets dedicated to plant cell wall. Investigation of the contribution made by each secretome to the saccharification of wheat straw demonstrated that most of them individually supplemented the industrial Trichoderma reesei CL847 enzymatic cocktail. Unexpectedly, the most striking effect was obtained with the phytopathogen Ustilago maydis that improved the release of total sugars by 57% and of glucose by 22%. Proteomic analyses of the best-performing secretomes indicated a specific enzymatic mechanism of U. maydis that is likely to involve oxido-reductases and hemicellulases. Conclusion This study provides insight into the lignocellulose-degradation mechanisms by filamentous fungi and allows for the identification of a number of enzymes that are potentially useful to further improve the industrial lignocellulose bioconversion process.
Mrljak, Vladimir; Kuleš, Josipa; Mihaljević, Željko; Torti, Marin; Gotić, Jelena; Crnogaj, Martina; Živičnjak, Tatjana; Mayer, Iva; Šmit, Iva; Bhide, Mangesh; Barić Rafaj, Renata
Vector-borne pathogens (VBPs) are a group of globally extended and quickly spreading pathogens that are transmitted by various arthropod vectors. The aim of the present study was to investigate the seroprevalence against Babesia canis, Anaplasma phagocytophilum, Borrelia burgdorferi sensu lato, Leishmania infantum, Dirofilaria immitis, and Ehrlichia canis in dogs in Croatia. We investigated 435 randomly selected apparently healthy dogs in 13 different locations of Croatia for antibodies to B. canis by indirect immunofluorescence using a commercial IFA IgG Antibody Kit. All samples were also tested for qualitative detection of D. immitis antigen and for antibodies to A. phagocytophilum, B. burgdorferi sensu lato, L. infantum, and E. canis with two point-of-care assays. Overall, 112 dogs (25.74%, 95% confidence interval [CI] 21.70-30.12) were serologically positive for one or more of the pathogens. B. canis was the most prevalent pathogen (20.00%, 95% CI 16.34-24.07), followed by A. phagocytophilum (6.21%, 95% CI 4.12-8.90), L. infantum, (1.38%, 95% CI 0.51-2.97), and B. burgdorferi sensu lato (0.69%, 95% CI 0.01-2.00). The lowest seroprevalence was for D. immitis and E. canis (0.46%, 95% CI 0.01-1.65). Coinfection was determined in 12 dogs (2.76%, 95% CI 1.43-4.77), of which 10 were positive to two pathogens (7 with B. canis and A. phagocytophilum and 1 B. canis with B. burgdorferi sensu lato or L. infantum or E. canis). One dog was positive to three pathogens and another dog to four pathogens. Seroprevalence for babesia was age, breed, and lifestyle/use dependent. Purebred dogs had almost half the chance of developing disease than crossbred (OR = 0.58, p < 0.026, 95% CI 0.37-0.94). Seropositivity to B. canis was 3.41 times higher for dogs that lived outdoors/shelter (p < 0.006) or 4.57 times higher in mixed/hunting (p < 0.001) compared to indoor/companion dogs. This is the first comprehensive survey of VBP seropositivity conducted in Croatia. Some
Alaboudi, Akram R; Ababneh, Mustafa; Osaili, Tareq M; Al Shloul, Khalaf
Vibrio parahaemolyticus is widely distributed in the marine environments and considered the leading cause of human gastroenteritis in Asian countries. A total of 150 marketed fish and 50 water and sediment samples from the Gulf of Aqaba were examined for the prevalence of pathogenic strains of V. parahaemolyticus. A total of 132 typical isolates obtained from the primary selective medium (thiosulfate-citrate bile salt sucrose agar) and showed positive biochemical properties were subjected to confirmation by polymerase chain reaction targeting the gyrB and toxR genes. These genes were confirmed at rates of 82% (108 isolates) and 72% (95 isolates), respectively. The toxR positive isolates were tested for the presence of thermolabile hemolysin (tlh), thermostable direct hemolysin (tdh), and tdh-related hemolysin (trh) virulence genes. Accordingly, the prevalence rates of pathogenic V. parahaemolyticus were 4%, 8%, and 12% in sediment, water, and fish samples, respectively. The 16S rRNA amplification and sequences were conducted for confirmation of the isolates and showing the relatedness among these isolates. The results showed that both 16S rRNA and toxR assays had same sensitivity and tested isolates had high nucleotide similarity irrespective of their sources. © 2015 Institute of Food Technologists®
Monroy Castro, Leidi Yunari; Lizarazo Forero, Luz Marina
The objectives of this study were to isolate and determine the presence of the pathogen Phytophthora ramorum and other potential pathogens of Quercus humboldtii, and evaluate the possibility of using the antagonistic capacity of bacteria isolated from rhizosphere and phyllosphere against them. The study was conducted in the conservation corridor Guantiva - La Rusia - Iguaque, in the municipalities of Encino (Santander), Arcabuco and Tipacoque (Boyaca). The phytopathogenic fungi were isolated using direct seeding of leaves with symptoms of fungal infection in OGY, Sabouraud, and PDA + Lactic acid at 0.2%. We used the plate counting technique for the isolation of bacteria from rhizospheric and bulk soil. Phytophthora ramorum was not isolated, but phytopathogenic fungi of the genus Fusarium spp., and Pestalotia spp., were obtained in the isolates. Microbial populations of rhizospheric and bulk soil were scarce, exhibited low diversity, and were dominated by few morphotypes. We identified four species of bacteria: Pseudomonas fluorescens, Bacillus macerans, Pinus sylvestris and Staphylococcus epidermidis. The phyllosphere community was dominated by Pseudomonas fluorescens. The species Pseudomonas fluorescens and Pinus sylvestris did not exhibited antagonistic properties against Pestalotia spp. Further studies are required to confirm Fusarium spp., and Pestalotia spp., pathogenic activity against Quercus humboldtii.
Full Text Available One of the main challenges in aquaponics is disease control. One possible solution for this is biological control with organisms exerting inhibitory effects on fish and plant pathogens. The aim of this study was to examine the potential of isolating microorganisms that exert an inhibitory effect on both plant and fish pathogens from an established aquaponic system. We obtained 924 isolates on selective King’s B agar and 101 isolates on MRS agar from different compartments of a model aquaponic system and tested them for antagonism against the plant pathogen Pythium ultimum and fish pathogen Saprolegnia parasitica. Overall, 42 isolates were able to inhibit both fungi. Although not yet tested in vivo, these findings open new options for the implementation of biological control of diseases in aquaponics, where plants and fish are cultivated in the same water recirculating system.
Maxim A. Khasnatinov
Full Text Available The aim of this study was to evaluate the risk of tick-borne infections in humans. The prevalence of 4 tick-borne pathogens was studied in the population of Ixodid ticks attacking human hosts in Irkutsk city and neighbouring territories from 2007 to 2017. Methods and Results: In total, 46,357 tick specimens detached from bitten people were analyzed. The antigen of tick-borne encephalitis virus (TBEV was detected in each tick individually by ELISA assay using a commercial kit for the envelope protein E of TBEV. Total RNA and DNA were extracted from ticks using a RiboPrep kit. Reverse transcription was performed using a Reverta-L kit and RNA\\DNA of TBEV; B. burgdorferi sensu lato, A. phagocytophylum and Ehrlichia muris\\E. chaffeensis were detected using a real-time multiplex PCR kit. In total, during 8 years of observations, I. persulcatus caused approximately 86% of bites, Dermacentor sp. 13.95 %, and H. concinna 0.05 %. The most prevalent tick-borne pathogen in I. persulcatus ticks was Lyme disease agent B. burgdorferi sensu lato, which was detected in 12±6.5% of specimens annually. A. phagocytophilum and Ehrlichia sp. were detected in 7.8±2.7% and 4.6±1.5% of specimens, respectively. TBEV was present in 1±0.7% of I. persulcatus. Conclusion: I. persulcatus remains the most important vector of tick-borne diseases to humans in Eastern Siberia. D. nuttalli and D. silvarum are much less aggressive to humans and are less infected with major tick-borne pathogens. H. concinna does not play any significant role as a disease vector. However, a rigorous analysis of TBEV spread in the Dermacentor sp. population is necessary.
Full Text Available Many ordinary surfaces and hands of healthcare givers in hospitals are sometimes inadequately decontaminated with routine disinfection techniques. It is necessary to determine the distribution of these pathogens in the hospitals. In this study 160 swab samples were collected from ten different surfaces including nurses’ hand swab, Nurses’ table top, door knob/handle, toilet seat, operation table, sink, stretcher, floor, bedrail, and cupboard. Biochemical tests were used to identify the bacteria. Kirby-Bauer-Clinical and Laboratory Standards Institute (CLSI modified single disc diffusion technique was used to determine the antibiogram profile of the pathogens at 0.5 scale McFarland’s standard (1.5 × 108 cells/ml. The total percentage prevalence of Staphylococcus aureus was 50.80%, Pseudomonas aeruginosa 28.60% and Escherichia coli 20.60%. Out of 20.60% of E. coli isolates7.7% were found to be E. coli O157:H7. S. aureus isolates were highly resistant to ampcillin and cefoxitin P. aeruginosa and E. coli were resistant to tetracycline. The multiple antibiotic resistance indexes of the pathogens were more than 0.2. Among the isolates, S. aureus showed more multidrug resistance (31.30% and E. coli had the least multidrug. Frequently touched surfaces within the hospital environment are contaminated by Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus. These pathogens can be transfer from surfaces to patients and to surfaces again through healthcare workers. The widespread use of antimicrobials, especially over- or inappropriate use of antibiotics, has contributed to an increased incidence of antimicrobial-resistant organisms.
A series of multilocus sequence-based nuclear DNA markers was developed to infer the phylogeographical history of the Basidiomycetous fungal pathogen Rhizoctonia solani AG-1 IA infecting rice and soybean worldwide. The strategy was based on sequencing of cloned genomic DNA fragments (previously used as RFLP probes) and subsequent screening of fungal isolates to detect single nucleotide polymorphisms (SNPs). Ten primer pairs were designed based on these sequences, which resulted in PCR amplification of 200-320 bp size products and polymorphic sequences in all markers analyzed. By direct sequencing we identified both homokaryon and heterokaryon (i.e. dikaryon) isolates at each marker. Cloning the PCR products effectively estimated the allelic phase from heterokaryotic isolates. Information content varied among markers from 0.5 to 5.9 mutations per 100 bp. Thus, the former RFLP codominant probes were successfully converted into six distinctively variable sequence-based nuclear DNA markers. Rather than discarding low polymorphism loci, the combination of these distinctively variable anonymous nuclear markers would constitute an asset for the unbiased estimate of the phylogeographical parameters such as population sizes and divergent times, providing a more reliable species history that shaped the current population structure of R. solani AG-1 IA. PMID:21637462
de Dios, Carmen Herrero; Román, Elvira; Monge, Rebeca Alonso; Pla, Jesús
In recent years, Mitogen-Activated Protein Kinase (MAPK) pathways have emerged as major regulators of cellular physiology. In the fungal pathogen Candida albicans, three different MAPK pathways have been characterized in the last years. The HOG pathway is mainly a stress response pathway that is activated in response to osmotic and oxidative stress and also participates regulating other pathways. The SVG pathway (or mediated by the Cek1 MAPK) is involved in cell wall formation under vegetative and filamentous growth, while the Mkc1-mediated pathway is involved in cell wall integrity. Oxidative stress is one of the types of stress that every fungal cell has to face during colonization of the host, where the cell encounters both hypoxia niches (i.e. gut) and high concentrations of reactive oxygen species (upon challenge with immune cells). Two pathways have been shown to be activated in response to oxidative stress: the HOG pathway and the MKC1-mediated pathway while the third, the Cek1 pathway is deactivated. The timing, kinetics, stimuli and functional responses generated upon oxidative stress differ among them; however, they have essential functional consequences that severely influence pathogenesis. MAPK pathways are, therefore, valuable targets to be explored in antifungal research.
Full Text Available Copper based metallo drugs were prepared and their antibacterial, antifungal, molecular mechanism of [Cu(SAlaPhen]·H2O and [Cu(SAlabpy]·H2O complexes were investigated. The [Cu(SAlaPhen]·H2O and [Cu(SAlabpy]·H2O were derived from the Schiff base alanine salicylaldehyde. [Cu(SAlaPhen]·H2O showed noteworthy antibacterial and antifungal activity than the [Cu(SAlabpy]·H2O and ligand alanine, salicylaldehyde. The [Cu(SAlaPhen]·H2O complex showed significant antibacterial activity against Salmonella typhi, Staphylococcus aureus, Salmonella paratyphi and the antifungal activity against Candida albicans and Cryptococcus neoformans in well diffusion assay. The mode of action of copper (II complex was analyzed by DNA cleavage activity and in silico molecular docking. The present findings provide important insight into the molecular mechanism of copper (II complexes in susceptible bacterial and fungal pathogens. These results collectively support the use of [Cu(SAlaPhen]·H2O complex as a suitable drug to treat bacterial and fungal infections.
Schoder, Dagmar; Strauß, Anja; Szakmary-Brändle, Kati; Stessl, Beatrix; Schlager, Sabine; Wagner, Martin
The EU has issued several directives and regulations pertaining to the importation of animals and products of animal origin (POAO) and veterinary controls on importation. Unfortunately, little information is available concerning associated risks and no attempts have been made to collect baseline data on the actual prevalence of zoonotic agents in POAO carried by travellers. To meet these challenges the EU recently introduced and financed a research project "PROMISE". Its main objectives were to assess the risks involved when foodborne pathogens are introduced to the EU via uncontrolled imports. With special permission of the Austrian health authorities, spot-checks were made of the luggage of 61,355 passengers from 240 flights from non-EU countries arriving at the Vienna International Airport (VIE airport). Over a period of eight months (August 2012 through March 2013) 1473 POAO items were confiscated. A total of 600 samples were suitable for Salmonella spp., Campylobacter spp., verotoxigenic Escherichia coli and Listeria monocytogenes prevalence analysis. Foodborne pathogens could be detected in 5% (30/600) of all samples. The highest prevalence was attributed to L. monocytogenes, at 2.5%, followed by VTEC and Salmonella spp. at 1.3% and 1.2%, respectively. Campylobacter spp. was not present in any of the 600 samples. Multi-locus sequence typing (MLST) of L. monocytogenes revealed that current sequence types (ST) corresponded to the worldwide most present clonal complexes 1, 2, 3, 5, 9, and 121. Generally, L. monocytogenes ST9 was the predominant allelic profile, which was mainly isolated from Turkish meat products. Copyright © 2014 Elsevier B.V. All rights reserved.
Stephen B Goodwin
Full Text Available The plant-pathogenic fungus Mycosphaerella graminicola (asexual stage: Septoria tritici causes septoria tritici blotch, a disease that greatly reduces the yield and quality of wheat. This disease is economically important in most wheat-growing areas worldwide and threatens global food production. Control of the disease has been hampered by a limited understanding of the genetic and biochemical bases of pathogenicity, including mechanisms of infection and of resistance in the host. Unlike most other plant pathogens, M. graminicola has a long latent period during which it evades host defenses. Although this type of stealth pathogenicity occurs commonly in Mycosphaerella and other Dothideomycetes, the largest class of plant-pathogenic fungi, its genetic basis is not known. To address this problem, the genome of M. graminicola was sequenced completely. The finished genome contains 21 chromosomes, eight of which could be lost with no visible effect on the fungus and thus are dispensable. This eight-chromosome dispensome is dynamic in field and progeny isolates, is different from the core genome in gene and repeat content, and appears to have originated by ancient horizontal transfer from an unknown donor. Synteny plots of the M. graminicola chromosomes versus those of the only other sequenced Dothideomycete, Stagonospora nodorum, revealed conservation of gene content but not order or orientation, suggesting a high rate of intra-chromosomal rearrangement in one or both species. This observed "mesosynteny" is very different from synteny seen between other organisms. A surprising feature of the M. graminicola genome compared to other sequenced plant pathogens was that it contained very few genes for enzymes that break down plant cell walls, which was more similar to endophytes than to pathogens. The stealth pathogenesis of M. graminicola probably involves degradation of proteins rather than carbohydrates to evade host defenses during the biotrophic
Full Text Available Abstract Background Extraintestinal pathogenic Escherichia coli are important pathogens of human and animal hosts. Some human and avian extraintestinal pathogenic E. coli are indistinguishable on the basis of diseases caused, multilocus sequence and phylogenetic typing, carriage of large virulence plasmids and traits known to be associated with extraintestinal pathogenic E. coli virulence. Results The gene tkt1 identified by a previous signature-tagged transposon mutagenesis study, was found on a 16-kb genomic island of avian pathogenic Escherichia coli (APEC O1, the first pathogenic Escherichia coli strain whose genome has been completely sequenced. tkt1 was present in 39.6% (38/96 of pathogenic Escherichia coli strains, while only 6.25% (3/48 of E. coli from the feces of apparently healthy chickens was positive. Further, tkt1 was predominantly present in extraintestinal pathogenic E. coli belonging to the B2 phylogenetic group, as compared to extraintestinal pathogenic E. coli of other phylogenetic groups. The tkt1-containing genomic island is inserted between the metE and ysgA genes of the E. coli K12 genome. Among different extraintestinal pathogenic E. coli of the B2 phylogenetic group, 61.7% of pathogenic Escherichia coli, 80.6% of human uropathogenic E.coli and 94.1% of human neonatal meningitis-causing E. coli, respectively, harbor a complete copy of this island; whereas, only a few avian fecal E. coli strains contained the complete island. Functional analysis showed that Tkt1 confers very little transketolase activity but is involved in peptide nitrogen metabolism. Conclusion These results suggest tkt1 and its corresponding genomic island are frequently associated with avian and human ExPEC and are involved in bipeptide metabolism.
Deb, Debasish; Shrestha, Ankita; Maiti, Indu B.; Dey, Nrisingha
Development of disease-resistant plant varieties achieved by engineering anti-microbial transgenes under the control of strong promoters can suffice the inhibition of pathogen growth and simultaneously ensure enhanced crop production. For evaluating the prospect of such strong promoters, we comprehensively characterized the full-length transcript promoter of Cassava Vein Mosaic Virus (CsVMV; -565 to +166) and identified CsVMV8 (-215 to +166) as the highest expressing fragment in both transient and transgenic assays. Further, we designed a new chimeric promoter ‘MUASCsV8CP’ through inter-molecular hybridization among the upstream activation sequence (UAS) of Mirabilis Mosaic Virus (MMV; -297 to -38) and CsVMV8, as the core promoter (CP). The MUASCsV8CP was found to be ∼2.2 and ∼2.4 times stronger than the CsVMV8 and CaMV35S promoters, respectively, while its activity was found to be equivalent to that of the CaMV35S2 promoter. Furthermore, we generated transgenic tobacco plants expressing the totiviral ‘Killer protein KP4’ (KP4) under the control of the MUASCsV8CP promoter. Recombinant KP4 was found to accumulate both in the cytoplasm and apoplast of plant cells. The agar-based killing zone assays revealed enhanced resistance of plant-derived KP4 against two deuteromycetous foliar pathogenic fungi viz. Alternaria alternata and Phoma exigua var. exigua. Also, transgenic plants expressing KP4 inhibited the growth progression of these fungi and conferred significant fungal resistance in detached-leaf and whole plant assays. Taken together, we establish the potential of engineering “in-built” fungal stress-tolerance in plants by expressing KP4 under a novel chimeric caulimoviral promoter in a transgenic approach. PMID:29556246
Jenevaldo Barbosa da Silva
Full Text Available Although the largest buffalo herd in the occident is in the north region of Brazil, few studies have been conducted to assess the prevalence of selected parasitic diseases in buffalo herd. The present study was therefore conducted to investigate the epidemiological of Toxoplasma gondii, Neospora caninum, Anaplasma marginale, Babesia bigemina, and Babesia bovis in water buffaloes in the north region of Brazil. A total of 4796 buffalo blood samples were randomly collected from five provinces and simultaneously analyzed by the IFAT and ELISA. The serological prevalence of T. gondii and N. caninum was 41.3% and 55.5% in ELISA and 35.7% and 48.8% in IFAT, respectively. The overall prevalence of A. marginale, B. bovis, and B. bigemina was 63%, 25%, and 21% by ELISA and 50.0%, 22.5%, and 18.8% by IFAT, respectively. This study shows valuable information regarding the serological survey of selected bovine pathogens in water buffaloes in the north region of Brazil which will likely be very beneficial for the management and control programs of this disease.
Szechyńska-Hebda, Magdalena; Wąsek, Iwona; Gołębiowska-Pikania, Gabriela; Dubas, Ewa; Żur, Iwona; Wędzony, Maria
The breeding for resistance against fungal pathogens in winter triticale (Triticosecale Wittm.) continues to be hindered by a complexity of the resistance mechanisms, strong interaction with environmental conditions, and dependence on the plant genotype. We showed, that temperature below 4 °C induced the plant genotype-dependent resistance against the fungal pathogen Microdochium nivale. The mechanism involved, at least, the adjustment of the reactions in the PSII proximity and photoprotection, followed by an improvement of the growth and development. The genotypes capable to develop the cold-induced resistance, showed a higher maximum quantum yield of PSII and a more efficient integration of the primary photochemistry of light reactions with the dark reactions. Moreover, induction of the photoprotective mechanism, involving at least the peroxidases scavenging hydrogen peroxide, was observed for such genotypes. Adjustment of the photosynthesis and stress acclimation has enabled fast plant growth and avoidance of the developmental stages sensitive to fungal infection. The same mechanisms allowed the quick regrow of plants during the post-disease period. In contrast, genotypes that were unable to develop resistance despite cold hardening had less flexible balancing of the photoprotection and photoinhibition processes. Traits related to: photosynthesis-dependent cold-acclimation and cold-induced resistance; biomass accumulation and growth; as well as protection system involving peroxidases; were integrated also at a genetic level. Analysing 95 lines of the mapping population SaKa3006×Modus we determined region on chromosomes 5B and 7R shared within all tested traits. Moreover, similar expression pattern of a set of the genes related to PSII was determined with the metaanalysis of the multiple microarray experiments. Comparable results for peroxidases, involving APXs and GPXs and followed by PRXs, indicated a similar function during cold acclimation and defense
Gisselle Yang Xie; Deanna H. Olson; Andrew R. Blaustein
Projected changes in climate conditions are emerging as significant risk factors to numerous species, affecting habitat conditions and community interactions. Projections suggest species range shifts in response to climate change modifying environmental suitability and is supported by observational evidence. Both pathogens and their hosts can shift ranges with climate...
The main infection courts for grapevine trunk pathogens are thought to be pruning wounds. As such, we expect pruning practices that require fewer/smaller wounds to be associated with fewer pruning-wound infections. In turn, minimal pruning may lead to less wood necroses and a lower diversity of trun...
Nicklas Samils; Malin Elfstrand; Daniel L. Lindner Czederpiltz; Jan Fahleson; Ake Olson; Christina Dixelius; Jan Stenlid
Heterobasidion annosum causes root and butt-rot in trees and is the most serious forest pathogen in the northern hemisphere. We developed a rapid and simple Agrobacterium-mediated method of gene delivery into H. annosum to be used in functional studies of candidate genes and for visualization of mycelial interactions. Heterobasidion annosum TC 32-1 was cocultivated at...
Hountondji, F.C.C.; Sabelis, M.W.; Hanna, R.; Sabelis, M.W.; Bruin, J.
The role of infochemicals in mediating interactions between herbivores and their foraging natural enemies, mainly predators and parasitoids, is well established, but very little is known about infochemical use in interactions between herbivores and their sit-and-wait pathogens. This paper reviews
Abstract of PhD thesis
Fusarium graminearum is a destructive plant pathogen that causes Fusarium head blight (FHB) on many crops, such as wheat, barley, rye and oat. In the first part of this thesis, we studied a transcription factor EBR1 that is required for radial growth and
Full Text Available Research has found that contagion-minimizing behavioral tendencies are amplified in pathogen-prevalent regions. We investigated whether reactions to the “swine flu” outbreak of 2009 were stronger among East Asians than Westerners, populations residing in regions that now enjoy comparable advances in healthcare but that are characterized by relatively high and low historical pathogen prevalence, respectively. In a survey, East Asians reported greater concerns about infection, especially from foreigners. Analyses of international air travel data around the time of the outbreak provided corroborating evidence: Immediately following the outbreak, airports in the Asia-Pacific region lost more international traffic relative to their Western counterparts, and East Asian airlines reported greater declines in international traffic compared to Western airlines. These differences are unlikely to reflect objective threat posed by swine flu (whose casualties were concentrated in the Americas; rather, they appear to reflect culturally adapted behavioral patterns forged and sustained by regionally variable levels of pathogen prevalence.
Gerwald A. Köhler
Full Text Available Candida albicans is the most important Candida species causing vulvovaginal candidiasis (VVC. VVC has significant medical and economical impact on women’s health and wellbeing. While current antifungal treatment is reasonably effective, supportive and preventive measures such as application of probiotics are required to reduce the incidence of VVC. We investigated the potential of the probiotics Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14 towards control of C. albicans. In vitro experiments demonstrated that lactic acid at low pH plays a major role in suppressing fungal growth. Viability staining following cocultures with lactobacilli revealed that C. albicans cells lost metabolic activity and eventually were killed. Transcriptome analyses showed increased expression of stress-related genes and lower expression of genes involved in fluconazole resistance, which might explain the increased eradication of Candida in a previous clinical study on conjoint probiotic therapy. Our results provide insights on the impact of probiotics on C. albicans survival.
Inderbitzin, Patrik; Bostock, Richard M; Davis, R Michael; Usami, Toshiyuki; Platt, Harold W; Subbarao, Krishna V
Knowledge of pathogen biology and genetic diversity is a cornerstone of effective disease management, and accurate identification of the pathogen is a foundation of pathogen biology. Species names provide an ideal framework for storage and retrieval of relevant information, a system that is contingent on a clear understanding of species boundaries and consistent species identification. Verticillium, a genus of ascomycete fungi, contains important plant pathogens whose species boundaries have been ill defined. Using phylogenetic analyses, morphological investigations and comparisons to herbarium material and the literature, we established a taxonomic framework for Verticillium comprising ten species, five of which are new to science. We used a collection of 74 isolates representing much of the diversity of Verticillium, and phylogenetic analyses based on the ribosomal internal transcribed spacer region (ITS), partial sequences of the protein coding genes actin (ACT), elongation factor 1-alpha (EF), glyceraldehyde-3-phosphate dehydrogenase (GPD) and tryptophan synthase (TS). Combined analyses of the ACT, EF, GPD and TS datasets recognized two major groups within Verticillium, Clade Flavexudans and Clade Flavnonexudans, reflecting the respective production and absence of yellow hyphal pigments. Clade Flavexudans comprised V. albo-atrum and V. tricorpus as well as the new species V. zaregamsianum, V. isaacii and V. klebahnii, of which the latter two were morphologically indistinguishable from V. tricorpus but may differ in pathogenicity. Clade Flavnonexudans comprised V. nubilum, V. dahliae and V. longisporum, as well as the two new species V. alfalfae and V. nonalfalfae, which resembled the distantly related V. albo-atrum in morphology. Apart from the diploid hybrid V. longisporum, each of the ten species corresponded to a single clade in the phylogenetic tree comprising just one ex-type strain, thereby establishing a direct link to a name tied to a herbarium specimen
Full Text Available The “rural” breeding of one or two pigs and their domestic slaughtering is a significant reality in the Veneto Region, as a consequence of an ancient tradition still surviving in the countryside. The present paper evaluates the hygienic conditions during slaughtering and processing, and the prevalence of foodborne pathogens both in live animals and in derived food, mainly sausages, salami and cold pork meats. The research underlines that, in main cases, the products derived from rural pigs are safe, if HACCP principles and good hygienic practices during slaughtering and processing are used. The presence of Listeria spp. in some products is probably derived from cross contaminations, not appropriate hygienic conditions, uncorrected salt percentage in the recipe, seasoning conditions: time, temperature, humidity...
Borlot, Felippe; Regan, Brigid M; Bassett, Anne S; Stavropoulos, D James; Andrade, Danielle M
Copy number variation (CNV) is an important cause of neuropsychiatric disorders. Little is known about the role of CNV in adults with epilepsy and intellectual disability. To evaluate the prevalence of pathogenic CNVs and identify possible candidate CNVs and genes in patients with epilepsy and intellectual disability. In this cross-sectional study, genome-wide microarray was used to evaluate a cohort of 143 adults with unexplained childhood-onset epilepsy and intellectual disability who were recruited from the Toronto Western Hospital epilepsy outpatient clinic from January 1, 2012, through December 31, 2014. The inclusion criteria were (1) pediatric seizure onset with ongoing seizure activity in adulthood, (2) intellectual disability of any degree, and (3) no structural brain abnormalities or metabolic conditions that could explain the seizures. DNA screening was performed using genome-wide microarray platforms. Pathogenicity of CNVs was assessed based on the American College of Medical Genetics guidelines. The Residual Variation Intolerance Score was used to evaluate genes within the identified CNVs that could play a role in each patient's phenotype. Of the 2335 patients, 143 probands were investigated (mean [SD] age, 24.6 [10.8] years; 69 male and 74 female). Twenty-three probands (16.1%) and 4 affected relatives (2.8%) (mean [SD] age, 24.1 [6.1] years; 11 male and 16 female) presented with pathogenic or likely pathogenic CNVs (0.08-18.9 Mb). Five of the 23 probands with positive results (21.7%) had more than 1 CNV reported. Parental testing revealed de novo CNVs in 11 (47.8%), with CNVs inherited from a parent in 4 probands (17.4%). Sixteen of 23 probands (69.6%) presented with previously cataloged human genetic disorders and/or defined CNV hot spots in epilepsy. Eight nonrecurrent rare CNVs that overlapped 1 or more genes associated with intellectual disability, autism, and/or epilepsy were identified: 2p16.1-p15 duplication, 6p25.3-p25.1 duplication, 8p23.3p
Klubal, Radek; Kopecky, Jan; Nesvorna, Marta; Sparagano, Olivier A E; Thomayerova, Jana; Hubert, Jan
Bacteria associated with the tick Ixodes ricinus were assessed in specimens unattached or attached to the skin of cats, dogs and humans, collected in the Czech Republic. The bacteria were detected by PCR in 97 of 142 pooled samples including 204 ticks, i.e. 1-7 ticks per sample, collected at the same time from one host. A fragment of the bacterial 16S rRNA gene was amplified, cloned and sequenced from 32 randomly selected samples. The most frequent sequences were those related to Candidatus Midichloria midichlori (71% of cloned sequences), followed by Diplorickettsia (13%), Spiroplasma (3%), Rickettsia (3%), Pasteurella (3%), Morganella (3%), Pseudomonas (2%), Bacillus (1%), Methylobacterium (1%) and Phyllobacterium (1%). The phylogenetic analysis of Spiroplasma 16S rRNA gene sequences showed two groups related to Spiroplasma eriocheiris and Spiroplasma melliferum, respectively. Using group-specific primers, the following potentially pathogenic bacteria were detected: Borellia (in 20% of the 142 samples), Rickettsia (12%), Spiroplasma (5%), Diplorickettsia (5%) and Anaplasma (2%). In total, 68% of I. ricinus samples (97/142) contained detectable bacteria and 13% contained two or more putative pathogenic groups. The prevalence of tick-borne bacteria was similar to the observations in other European countries.
Prapphal, Nuanchan; Suwanjutha, Subharee; Durongkaveroj, Pravin; Lochindarat, Sorasak; Kunakorn, Mongkol; Deerojanawong, Jitladda; Chantarojanasiri, Teerachai; Supanitayaonon, Yingsak; Janedittakarn, Pisit
To determine the prevalence of atypical pneumonia and clinical presentations in patients with community acquired pneumonia (CAP). A prospective multi-centered study was performed in patients aged > or = 2 years with the diagnosis of CAP who were treated at seven governmental hospitals in Bangkok from December 2001 to November 2002. The diagnosis of current infection was based on > or = 4 fold rise in antibody sera or persistently high antibody titers together with the presence of DNA of M. pneumoniae or C. pneumoniae in respiratory secretion or antigen of L. pneumophila in the urine. Clinical presentations were compared between patients with atypical pneumonia and unspecified pneumonia. Of 292 patients, 18.8% had current infection with atypical respiratory pathogens (M. pneumoniae 14.0%, C. pneumoniae 3.4%, L. pneumophila 0.4% and mixed infection 1.0%). Only age at presentation was significantly associated with atypical pneumonia in adults, while absence of dyspnea, lobar consolidation, and age > or = 5 years were significant findings for atypical pneumonia in children. The present study confirms the significance of atypical pathogens in adults and children. Moreover lobar consolidation is likely to predict atypical pneumonia in childhood CAP.
Innocenti, Alessio; Mühlschlegel, Fritz A; Hall, Rebecca A; Steegborn, Clemens; Scozzafava, Andrea; Supuran, Claudiu T
The catalytic activity and inhibition of the beta-carbonic anhydrases (CAs, EC 184.108.40.206) from the pathogenic fungi Candida albicans (Nce103) and Cryptococcus neoformans (Can2) with inorganic anions such as halogenides, pseudohalogenides, bicarbonate, carbonate, nitrate, nitrite, hydrogen sulfide, bisulfite, perchlorate, sulfate were investigated. The two enzymes showed appreciable CO(2) hydrase activity (k(cat) in the range of (3.9-8.0)x10(5)s(-1), and k(cat)/K(m) in the range of (4.3-9.7)x10(7)M(-1)s(-1)). Can2 was weakly inhibited by cyanide and sulfamic acid (K(I)s of 8.22-13.56 mM), while all other anions displayed more potent inhibition. Nce103 was strongly inhibited by cyanide and carbonate (K(I)s of 10-11 microM), and weakly inhibited by sulfate, phenylboronic, and phenyl arsonic acid (K(I)s of 14.15-30.85 mM). These data demonstrate that pathogenic, fungal beta-CAs may be targets for the development of antifungals that have a novel mechanism of action.
Abdollahzadeh, Jafar; Zolfaghari, Sajedeh
Progress in molecular biology and the advent of rapid and accurate molecular techniques have contributed to precise and rapid detection and differentiation of microbial pathogens. Identification of the Botryosphaeriaceae species based on morphology has been problematic over time. In this study, we used rep-PCR technique as a molecular tool for typing and differentiation of the Botryosphaeriaceae species, well-known and cosmopolitan fungal pathogens on woody plants. Three primer sets BOX, ERIC and REP were used to differentiate 27 species belong to eight genera. The majority of them were examined in terms of typing and differentiation using molecular methods for the first time. All the primer sets were able to generate species-specific DNA fingerprints from all the tested strains, with two exceptions in the genera Diplodia and Spencermartinsia. Despite the deficiency of each primer sets to separate a few species, cluster analysis of combined data sets indicated the ability of rep-PCR technique to separate 26 out of 27 examined species in highly supported clusters corresponded to the species recognized based on DNA sequence data. Our findings revealed the efficiency of rep-PCR for detection and differentiation of the Botryosphaeriaceae species, especially cryptic species with the same ITS sequences and similar morphology. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.
Amelia E. Van Pelt
Full Text Available Foodborne illness burdens individuals around the world and may be caused by consuming fresh produce contaminated with bacterial, parasite, and viral pathogens. Pathogen contamination on produce may originate at the farm and packing facility. This research aimed to determine the prevalence of human pathogens (bacteria, parasites, and viruses on fresh produce (fruits, herbs, and vegetables on farms and in packing facilities worldwide through a systematic review of 38 peer-reviewed articles. The median and range of the prevalence was calculated, and Kruskal–Wallis tests and logistic regression were performed to compare prevalence among pooled samples of produce groups, pathogen types, and sampling locations. Results indicated a low median percentage of fresh produce contaminated with pathogens (0%. Both viruses (p-value = 0.017 and parasites (p-value = 0.033, on fresh produce, exhibited higher prevalence than bacteria. No significant differences between fresh produce types or between farm and packing facility were observed. These results may help to better quantify produce contamination in the production environment and inform strategies to prevent future foodborne illness.
Niessen, Ludwig; Luo, Jie; Denschlag, Carla; Vogel, Rudi F
Bacterial pathogens and toxicants, parasites as well as mycotoxin producing fungi are the major biotic factors influencing the safety of food. Moreover, viral infections and prions may be present as quasi biotic challenging factors. A vast array of culture dependent analytical methods and protocols for food safety testing has been developed during the past decades. Presently, protocols involving molecular biological techniques such as PCR-based nucleic acid amplification and hybridization have become available for many of the known pathogens with their major advantages being rapidness, high sensitivity and specificity. However, this type of assays is still quite labor- and cost intensive and mostly cannot be operated directly in the field. Recently, loop-mediated isothermal amplification (LAMP) of DNA has emerged as an alternative to the use of PCR-based methods not only in food safety testing but also in a wide array of application. Its advantages over PCR-based techniques are even shorter reaction time, no need for specific equipment, high sensitivity and specificity as well as comparably low susceptibility to inhibitors present in sample materials which enables detection of the pathogens in sample materials even without time consuming sample preparation. The present article presents a critical review of the application of LAMP-based methods and their usefulness in detecting and identifying food borne bacterial pathogens and toxicants as well as mycotoxin producing food borne fungi as compared to other methods. Moreover does it elaborate on new developments in the design and automation of LAMP-based assays and their implications for the future developments of food testing. Copyright © 2013 Elsevier Ltd. All rights reserved.
Jindřichová, Barbora; Fodor, J.; Šindelářová, Milada; Burketová, Lenka; Valentová, O.
Roč. 72, č. 2 (2011), s. 149-156 ISSN 0098-8472 R&D Projects: GA ČR GA522/08/1581; GA MŠk MEB040923 Institutional research plan: CEZ:AV0Z50380511 Keywords : hydrogen peroxide * antioxidant enzymes * hemibiotrophic pathogen Subject RIV: GF - Plant Pathology, Vermin, Weed, Plant Protection Impact factor: 2.985, year: 2011
Stukenbrock, Eva Holtgrewe; Christiansen, Freddy Bugge; Hansen, Troels Toftebjerg; Dutheil, Julien Yann; Schierup, Mikkel Heide
In a genome alignment of five individuals of the ascomycete fungus Zymoseptoria pseudotritici, a close relative of the wheat pathogen Z. tritici (synonym Mycosphaerella graminicola), we observed peculiar diversity patterns. Long regions up to 100 kb without variation alternate with similarly long regions of high variability. The variable segments in the genome alignment are organized into two main haplotype groups that have diverged ∼3% from each other. The genome patterns in Z. pseudotritici are consistent with a hybrid speciation event resulting from a cross between two divergent haploid individuals. The resulting hybrids formed the new species without backcrossing to the parents. We observe no variation in 54% of the genome in the five individuals and estimate a complete loss of variation for at least 30% of the genome in the entire species. A strong population bottleneck following the hybridization event caused this loss of variation. Variable segments in the Z. pseudotritici genome exhibit the two haplotypes contributed by the parental individuals. From our previously estimated recombination map of Z. tritici and the size distribution of variable chromosome blocks untouched by recombination we estimate that the hybridization occurred ∼380 sexual generations ago. We show that the amount of lost variation is explained by genetic drift during the bottleneck and by natural selection, as evidenced by the correlation of presence/absence of variation with gene density and recombination rate. The successful spread of this unique reproductively isolated pathogen highlights the strong potential of hybridization in the emergence of pathogen species with sexual reproduction.
Full Text Available The study determined the relative importance of Escherichia coli, E. coli O157, Salmonella spp., Clostridium spp., rotavirus, Cryptosporidium spp., and Strongyloides westeri in foal (diarrhoeic and non-diarrhoeic available for sampling during the foaling season of 2010 and determined their sensitivity to antimicrobial agents. A cross-sectional study was conducted on 164 foals (9 diarrhoeic and 155 non-diarrhoeic from 15 farms in Trinidad. Isolation and detection of enteric pathogens followed standard methods, and the antibiograms of E. coli and Salmonella spp. were determined using the disc diffusion method. All organisms investigated were detected except E. coli O157. A high prevalence of E. coli (85.0%, Cryptosporidium spp. (64.8%, Strongyloides westeri (35.7% was seen, but the prevalence was comparatively low for Clostridium spp. (12.9%, Salmonella spp. (4.4% and rotavirus (2.1%. Only Salmonella spp. was isolated at a statistically significantly (<0.05; 2 higher frequency from diarrhoeic (25.0% than non-diarrhoeic (4.0% foals. Amongst E. coli isolates, the frequency of resistance was higher in isolates from diarrhoeic compared with non-diarrhoeic foals but the difference was only statistically significant (<0.05; 2 for tetracycline. All isolates of Salmonella spp. were sensitive to streptomycin and sulphamethoxazole/trimethoprim, a finding that may have therapeutic significance.
Wang, Xiao'e; Basnayake, B M Vindhya S; Zhang, Huijuan; Li, Guojun; Li, Wei; Virk, Nasar; Mengiste, Tesfaye; Song, Fengming
Transcription factors of the NAC family are known to be involved in various growth or developmental processes and in regulation of response to environmental stresses. In the present study, we report that Arabidopsis ATAF1 is a negative regulator of defense responses against both necrotrophic fungal and bacterial pathogens. Expression of ATAF1 was downregulated after infection with Botrytis cinerea or Pseudomonas syringae pv. tomato or after treatment with salicylic acid (SA), jasmonic acid, and 1-amino cyclopropane-1-carboxylic acid (the precursor of ethylene biosynthesis). Transgenic plants that overexpress the ATAF1 gene (ATAF1-OE) showed increased susceptibility while expression of an ATAF1 chimeric repressor construct (ATAF1-SRDX) exhibited enhanced resistance to P. syringae pv. tomato DC3000, B. cinerea, and Alternaria brassicicola. The ataf1 mutant plants showed no significant resistance against the pathogens tested. After inoculation with B. cinerea or P. syringae pv. tomato DC3000, expressions of defense-related genes PR-1, PR-5. and PDF1.2 were upregulated in the ATAF1-SRDX plants but attenuated or unchanged in the ATAF1-OE plants. In ATAF1-OE plants, SA-induced expression of pathogenesis-related genes and disease resistance against P. syringae pv. tomato DC3000 was partially suppressed. Increased levels of reactive oxygen species (i.e., H(2)O(2) and superoxide anion) accumulated only in the ATAF1-OE but not in the ATAF1-SRDX plants after Botrytis spp. infection. Our studies provide direct genetic evidence for the role of ATAF1 as a negative regulator of defense response against different type of pathogens.
Simon A Johnston
Full Text Available The lysis of infected cells by disease-causing microorganisms is an efficient but risky strategy for disseminated infection, as it exposes the pathogen to the full repertoire of the host's immune system. Cryptococcus neoformans is a widespread fungal pathogen that causes a fatal meningitis in HIV and other immunocompromised patients. Following intracellular growth, cryptococci are able to escape their host cells by a non-lytic expulsive mechanism that may contribute to the invasion of the central nervous system. Non-lytic escape is also exhibited by some bacterial pathogens and is likely to facilitate long-term avoidance of the host immune system during latency. Here we show that phagosomes containing intracellular cryptococci undergo repeated cycles of actin polymerisation. These actin 'flashes' occur in both murine and human macrophages and are dependent on classical WASP-Arp2/3 complex mediated actin filament nucleation. Three dimensional confocal imaging time lapse revealed that such flashes are highly dynamic actin cages that form around the phagosome. Using fluorescent dextran as a phagosome membrane integrity probe, we find that the non-lytic expulsion of Cryptococcus occurs through fusion of the phagosome and plasma membranes and that, prior to expulsion, 95% of phagosomes become permeabilised, an event that is immediately followed by an actin flash. By using pharmacological agents to modulate both actin dynamics and upstream signalling events, we show that flash occurrence is inversely related to cryptococcal expulsion, suggesting that flashes may act to temporarily inhibit expulsion from infected phagocytes. In conclusion, our data reveal the existence of a novel actin-dependent process on phagosomes containing cryptococci that acts as a potential block to expulsion of Cryptococcus and may have significant implications for the dissemination of, and CNS invasion by, this organism.
Full Text Available BACKGROUND: Plant sucrose transporter activities were shown to respond to changes in the extracellular pH and redox status, and oxidizing compounds like glutathione (GSSG or H(2O(2 were reported to effect the subcellular targeting of these proteins. We hypothesized that changes in both parameters might be used to modulate the activities of competing sucrose transporters at a plant/pathogen interface. We, therefore, compared the effects of redox-active compounds and of extracellular pH on the sucrose transporters UmSRT1 and ZmSUT1 known to compete for extracellular sucrose in the Ustilago maydis (corn smut/Zea mays (maize pathosystem. METHODOLOGY/PRINCIPAL FINDINGS: We present functional analyses of the U. maydis sucrose transporter UmSRT1 and of the plant sucrose transporters ZmSUT1 and StSUT1 in Saccharomyces cerevisiae or in Xenopus laevis oocytes in the presence of different extracellular pH-values and redox systems, and study the possible effects of these treatments on the subcellular targeting. We observed an inverse regulation of host and pathogen sucrose transporters by changes in the apoplastic pH. Under none of the conditions analyzed, we could confirm the reported effects of redox-active compounds. CONCLUSIONS/SIGNIFICANCE: Our data suggest that changes in the extracellular pH but not of the extracellular redox status might be used to oppositely adjust the transport activities of plant and fungal sucrose transporters at the host/pathogen interface.
S M Rudramurthy
Full Text Available The prevalence of fungal spores in the hospital air is essential to understand the hospital-acquired fungal infections. Air conditioners (ACs used in hospitals may either reduce spores in air or be colonised by fungi and aid in its dissemination. The present study was conducted to assess the fungal spore burden in AC and non-AC areas. We found a high fungal spore count in air irrespective of whether the area was AC or non-AC. The most predominant species isolated were Aspergillus flavus and Aspergillus fumigatus. Such high concentrations of pathogenic fungi in air may predispose individuals to develop disease.
Fondrevez, M; Minvielle, B; Labbé, A; Houdayer, C; Rose, N; Esnault, E; Denis, M
The prevalence of pathogenic Yersinia enterocolitica in French slaughter-aged pigs was estimated by sampling 3120 pigs from 96 batches in 16 slaughterhouses from January 2010 to February 2011. Respectively, 36 batches (20 pigs/batch) and 60 batches (40 pigs/batch) were considered during the cold period and the warm period. Tonsils were swabbed before the chilling step. Pathogenic Y. enterocolitica was detected after enrichment in ITC and streaking on CIN and YeCM media. Typical isolates were confirmed as Y. enterocolitica and biotyped by biochemical tests as described in the ISO 10273:2003 method. Of the tested pigs, 13.7% (CI95% [10.1-17.3]) were found positive for pathogenic Y. enterocolitica and 74.3% (CI95% [64.8-83.8]) of the pig batches contained at least one positive pig. The percentage of positive pigs per batch was generally low; 60.3% of positive batches contained fewer than 5 positive pigs. The prevalence of the pathogen at the batch level remained unchanged throughout this one-year study, but the prevalence in pigs was significantly higher during the warm period than during the cold period. Biotype 4 was the most prevalent biotype among the 827 isolated strains (91.9% of the isolates), followed by biotype 3 (7.25% of the isolates). Six isolates were of biotype 5 and one of biotype 2. Biotype 4 was found in all the 16 participating slaughterhouses, biotype 3 in ten slaughterhouses and biotype 5 in four. This study provides valuable recent figures for the prevalence of pathogenic Y. enterocolitica in French pigs. It also highlights the seasonal aspect of the carriage of this pathogen by pigs, a pattern which differs from those in other countries. Copyright © 2014 Elsevier B.V. All rights reserved.
López-García, Belén; Veyrat, Ana; Pérez-Payá, Enrique; González-Candelas, Luis; Marcos, Jose F
In this study, we evaluated the activity of short antimicrobial peptides against different fungal isolates that cause postharvest decay of fresh fruits. The previously identified hexapeptides PAF19, PAF26 and LfcinB4-9 inhibited the in vitro growth of isolates from Penicillium digitatum and P. italicum, and from Alternaria and Geotrichum genera, being no active against Rhizopus, Mucor and Aspergillus. The results extend our previous observations on the specific and distinct activity profiles of this class of antifungal peptides. In addition, peptide activities were compared with that of two fungicides used for citrus fruit preservation, thiabendazole (TBZ) and imazalil (IMZ). We observed a lack of correlation between peptide and fungicide sensitivity among different species. Importantly, P. digitatum and P. italicum isolates resistant to fungicides were susceptible to peptides and our data suggest that common multiple drug resistance mechanisms are not active against this class of peptides. The in vitro peptide inhibition was correlated with a retard of the decay caused by Penicillium on citrus fruits, and this effect was comparable for both fungicide-resistant and -sensitive isolates. Comparison of PAF26 and TBZ in vitro minimum inhibitory concentration (MIC) values and their in vivo effect on citrus decay indicated that PAF26 performed in vivo better than TBZ.
Juvvadi, Praveen Rao; Belina, Detti [Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham, NC (United States); Soderblom, Erik J.; Moseley, M. Arthur [Duke Proteomics Core Facility, Institute for Genome Sciences and Policy, Duke University, Durham, NC (United States); Steinbach, William J., E-mail: email@example.com [Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham, NC (United States); Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC (United States)
Highlights: ► In vivo interactions of the novel septin AspE were identified by GFP-Trap® affinity purification. ► Septins AspA, AspB, AspC and AspD interacted with AspE in vivo. ► Actin and tubulin interacted with AspE in vivo. ► AspE is phosphorylated at six serine residues in vivo. -- Abstract: We previously analyzed the differential localization patterns of five septins (AspA–E), including a filamentous fungal-specific septin, AspE, in the human pathogen Aspergillus fumigatus. Here we utilized the A. fumigatus strain expressing an AspE–EGFP fusion protein and show that this novel septin with a tubular localization pattern in hyphae is phosphorylated in vivo and interacts with the other septins, AspA, AspB, AspC and AspD. The other major proteins interacting with AspE included the cytoskeletal proteins, actin and tubulin, which may be involved in the organization and transport of the septins. This is the first report analyzing the phosphorylation of AspE and localizing the sites of phosphorylation, and opens opportunities for further analysis on the role of post-translational modifications in the assembly and organization of A. fumigatus septins. This study also describes the previously unknown interaction of AspE with the actin-microtubule network. Furthermore, the novel GFP-Trap® affinity purification method used here complements widely-used GFP localization studies in fungal systems.
Thorman, Royne; Neovius, Martin; Hylander, Britta
Early detection and treatment of local oral fungal infection (OFI) minimize the risk of overgrowth and more serious complications such as invasive infections. Generalized fungal infection increases both morbidity and mortality in end-stage renal disease (ESRD) patients. This study reports the prevalence of ongoing OFI in patients with ESRD and presents correlations with dental microbial plaque formation and mouth dryness. It also describes how oral fungal growth correlates with oral lesions associated with fungal infection. From March 2007 to October 2008, 93 ESRD patients and 45 age- and gender-matched controls were consecutively asked to participate in the study. In total, 34 patients were treated with peritoneal dialysis (PD) and 59 with haemodialysis (HD). OFI was diagnosed by taking two smear layers from the buccal mucosa. The samples from each side of the mouth were stained with the periodic acid Schiff (PAS) method. The associations between histological findings, age, gender, type of dialysis treatment, tobacco habits, self-experienced mouth dryness, taste disturbances, dental plaque and gingivitis were investigated. The presence of erythematous oral stomatitis, membranous candidiasis and angular cheilitis was noted to clarify how the presence of fungal hyphae correlate with oral lesions associated with OFI. OFI was found in 32% of the ESRD patients and 11% of the controls (p=0.007). An extensive OFI, defined as frequent fungal hyphae formations in oral mucosal smear layers, was found in 3% of the PD and 17% of the HD patients. Oral lesions, defined as clinical signs associated with OFI such as erythematous oral stomatitis, membranous candidiasis or angular cheilitis, were found in 37% of the patients with OFI, while 5% of the patients without findings of fungal infection presented oral lesions associated with OFI (p=0.0002). Furthermore, patients with self-reported mouth dryness were three times more likely (p=0.02) to be diagnosed with OFI. ESRD patients
... Español Eye Health / Eye Health A-Z Fungal Keratitis Sections What is Fungal Keratitis? Fungal Keratitis Causes ... Keratitis Symptoms Fungal Keratitis Treatment What is Fungal Keratitis? Leer en Español: ¿Qué Es la Queratitis Fúngica? ...
Full Text Available North American crayfish species are natural hosts of the crayfish plague pathogen Aphanomyces astaci. The spiny-cheek crayfish Orconectes limosus, widespread in Central Europe, is the main reservoir of A. astaci in Czech Republic. We tested if there are temporal changes in the prevalence of infected individuals (i.e., the proportion of individuals in which the pathogen is detected in spiny-cheek crayfish populations. Crayfish from three populations shown previously to be infected to different extents (high, intermediate and low, were repeatedly sampled in different years (2004–2010 and seasons. The presence of A. astaci in the soft abdominal crayfish cuticle was tested by specific amplification of the pathogen DNA. There was no substantial temporal variation in pathogen prevalence in the highly and very lowly infected populations. However, a significant long-term as well as seasonal decrease was found in the intermediately infected population. This decline could be related to a decrease in population density over the studied years, and to crayfish seasonal moulting, respectively. A reliable estimate of pathogen prevalence in American crayfish populations thus requires repeated monitoring over years, preferably during the same season before the main period of crayfish moulting.
Barreto, R W; Evans, H C
A two-year survey of the fungi associated with two important congeneric pantropical weeds, Euphorbia heterophylla and E. hirta, was conducted in part of their native range in southern Brazil. Sampling was concentrated mainly in Rio de Janeiro State and ten species were identified as pathogens of these weeds. Two taxa, Botrytis ricini and Uromyces euphorbiae, were common to both weed hosts. Alternaria euphorbiicola, Bipolaris euphorbiae, Melampsora sp., Oidium sp. and Sphaceloma poinsettiae were recorded only from E. heterophylla, whereas Colletotrichum gloeosporioides, Sphaceloma sp. and Sphaerotheca fuliginea were restricted to E. hirta. Botrytis ricini and Colletotrichum gloeosporioides are new records for E. hirta, and Alternaria euphorbiicola and Sphaerotheca fuliginea are new host records for Brazil. Bipolaris euphorbiae, previously identified as Helminthosporium sp., is considered to be the correct name for the causal agent of a major disease of E. heterophyllum in Brazil. The potential of these pathogens as biocontrol agents is discussed and the mycobiota associated with both these weeds worldwide is reviewed.
Full Text Available The dynamic changes of the levels of volatile organic compounds (VOCs produced by Bacillus subtilis CF-3 and their biocontrol effects on common fungal pathogens were researched in this study. The results showed that the VOCs in 24-h fermentation liquid (24hFL of B. subtilis CF-3 inhibited mycelial growth of Botrytis cinerea, Colletotrichum gloeosporioides, Penicillium expansum, Monilinia fructicola, and Alternaria alternata, with a mean inhibition rate of 59.97%. The inhibitory effect on M. fructicola and C. gloeosporioides was the highest; they were therefore selected as target fungal pathogens for further experiments. Based on headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS, 74 potential VOCs were identified during the fermentation: 15 alcohols, 18 ketones, 4 pyrazines, 4 esters, 10 acids, 5 phenols, 3 hydrocarbons, 3 amines, 2 aldehydes, 5 ethers, and 5 other components. At different fermentation times, the type and content of VOCs were different. Most of the potential VOCs (62 VOCs were identified in the 48hFL. The inhibition rates of all VOCs reached their peaks (73.46% on M. fructicola and 63.63% on C. gloeosporioides in the 24hFL. Among the identified VOCs, 2,4-di-tert-butylphenol, 1-octanol, and benzothiazole showed significant positive correlations with the rates of M. fructicola and C. gloeosporioides inhibition. Benzoic acid and benzaldehyde showed a significant positive correlation with the rates of M. fructicola inhibition, and anisole and 3-methylbutanal showed a significant positive correlation with the rates of C. gloeosporioides inhibition. In vitro, 2,4-di-tert-butylphenol showed a strong inhibitory effect on both M. fructicola and C. gloeosporioides. In vivo, benzothiazole showed the strongest inhibitory effect on the mycelial extensions of both M. fructicola and C. gloeosporioides, which also led to an increased rate of healthy fruit. The results of the present study
Vincy, M. V.; Brilliant, R.; Pradeepkumar, A. P.
The Meenachil, the only river that flows through the heart of the Kottayam district of Kerala state, India was selected for the study. The present study has been carried out with an objective to systematically examine the prevalence of indicator and pathogenic microorganisms and to compare the microbiological quality of the river water during the pre-monsoon and post-monsoon seasons. Water samples from 44 different sites during pre-monsoon and post-monsoon seasons were collected for the analysis. During the pre-monsoon period, the faecal coliform count ranged from 230 to 110,000 MPN/100 ml while there was a variation from 200 to 4600 MPN/100 ml during the post-monsoon period. When the faecal streptococci count was analysed, it ranged from 140 to 110,000 MPN/100 ml during the pre-monsoon and 70 to 4600 MPN/100 ml during the post-monsoon seasons, respectively. All the samples collected were found to have total viable count (TVC) higher than those prescribed by Bureau of Indian Standards (ISI 1991). Total viable counts were found in the range of 1.1 × 102 to 32 × 102 cfu/ml in the pre-monsoon and 1.0 × 102 to 26 × 102 cfu/ml in the post-monsoon. The presence of faecal indicator bacteria, Escherichia coli and potentially pathogenic bacteria, Vibrio cholerae, Vibrio parahaemolyticus and Salmonella enterica in the Meenachil River indicates that the bacteriological quality of the Meenachil River is poor. Moreover, it sheds light to the fact that raw sewage is being dumped into the Meenachil River. Urban runoffs and effluents of rubber factories appear to be the important sources of faecal contamination in the river. From this study, we conclude that these water bodies pose significant public health hazards. Adequate sanitary infrastructure will help in preventing source water contamination. Besides this, public health education aimed at improving personal, household and community hygiene is urgent.
Sang, Willie Kipkemboi; Oundo, Valerie; Schnabel, David
Diarrhoea is one of the main causes of morbidity and mortality among children in sub-Saharan Africa, and one of the main causes of hospital admissions in rural areas of Kenya. In Kenya, antimicrobial resistance surveillance has been conducted only at the institutional levels, with limited sharing of information and analysis of data. As a result, the actual scale of regional or national antimicrobial drug resistance is not well defined. Stool samples were collected between 1 October 2007 and 30 September 2008 from a total of 651 outpatients with diarrhoea who were under five years of age in four provinces of Kenya. Conventional, biochemical methods, multiplex PCR and antimicrobial susceptibility were conducted to identify the bacterial causes and virulence factors in the isolates, respectively. Of the 651 patients screened, we identified the causes of 115 cases (17.7%) as follows: Pathogenic E. coli (11.2%) [enteroaggregative (8.9%), enterotoxigenic (1.2%), enteroinvasive (0.6%), shigatoxigenic (0.5%)], Salmonella (3.5%), Shigella (2%) and Vibrio cholera O1 (0.7%). The highest levels of resistance among the E. coli isolates were observed in ampicillin and trimethoprim/sulphamethoxazole each at 95% followed by tetracycline at 81%. Shigella isolate levels of resistance ranged from 80% to 100% for ampicillin, tetracycline and trimethoprim/sulphamethoxazole. The highest prevalence of antimicrobial resistance was to ampicillin followed by trimethoprim/sulphamethoxazole and tetracycline. Though still at low levels, the major concern from our findings is the emerging resistance of enteric pathogens that was observed to quinolones (ciprofloxacin, nalidixic acid, norfloxacin) and gentamycin.
Marchello, Christian; Dale, Ariella Perry; Thai, Thuy Nhu; Han, Duk Soo; Ebell, Mark H
Community-acquired pneumonia (CAP), acute cough, bronchitis, and lower respiratory tract infections (LRTI) are often caused by infections with viruses or Streptococcus pneumoniae . The prevalence of atypical pathogens Mycoplasma pneumoniae , Chlamydophila pneumoniae , Legionella pneumophila , and Bordetella pertussis among patients with these illnesses in the ambulatory setting has not been previously summarized. We set out to derive prevalence information from the existing literature. We performed a systematic review of MEDLINE for prospective, consecutive-series studies reporting the prevalence of M pneumoniae, C pneumoniae, L pneumophila and/or B pertussis in outpatients with cough, acute bronchitis, LRTI, or CAP. Articles were independently reviewed by 2 authors for inclusion and abstraction of data; discrepancies were resolved by consensus discussion. A meta-analysis was performed on each pathogen to calculate the pooled prevalence estimates using a random effects model of raw proportions. Fifty studies met our inclusion criteria. While calculated heterogeneity was high, most studies reported prevalence for each pathogen within a fairly narrow range. In patients with CAP, the overall prevalences of M pneumoniae and C pneumoniae were 10.1% (95% CI, 7.1%-13.1%) and 3.5% (95% CI, 2.2%-4.9%), respectively. Consistent with previous reports, M pneumoniae prevalence peaked in roughly 6-year intervals. Overall prevalence of L pneumophila was 2.7% (95% CI, 2.0%-3.4%), but the organism was rare in children, with only 1 case in 1,765. In patients with prolonged cough in primary care, the prevalence of B pertussis was 12.4% (95% CI, 4.9%-19.8%), although it was higher in studies that included only children (17.6%; 95% CI, 3.4%-31.8%). Atypical bacterial pathogens are relatively common causes of lower respiratory diseases, including cough, bronchitis, and CAP. Where surveillance data were available, we found higher prevalences in studies where all patients are tested for
Gisselle Yang Xie
Full Text Available Projected changes in climate conditions are emerging as significant risk factors to numerous species, affecting habitat conditions and community interactions. Projections suggest species range shifts in response to climate change modifying environmental suitability and is supported by observational evidence. Both pathogens and their hosts can shift ranges with climate change. We consider how climate change may influence the distribution of the emerging infectious amphibian chytrid fungus, Batrachochytrium dendrobatidis (Bd, a pathogen associated with worldwide amphibian population losses. Using an expanded global Bd database and a novel modeling approach, we examined a broad set of climate metrics to model the Bd-climate niche globally and regionally, then project how climate change may influence Bd distributions. Previous research showed that Bd distribution is dependent on climatic variables, in particular temperature. We trained a machine-learning model (random forest with the most comprehensive global compilation of Bd sampling records (~5,000 site-level records, mid-2014 summary, including 13 climatic variables. We projected future Bd environmental suitability under IPCC scenarios. The learning model was trained with combined worldwide data (non-region specific and also separately per region (region-specific. One goal of our study was to estimate of how Bd spatial risks may change under climate change based on the best available data. Our models supported differences in Bd-climate relationships among geographic regions. We projected that Bd ranges will shift into higher latitudes and altitudes due to increased environmental suitability in those regions under predicted climate change. Specifically, our model showed a broad expansion of areas environmentally suitable for establishment of Bd on amphibian hosts in the temperate zones of the Northern Hemisphere. Our projections are useful for the development of monitoring designs in these areas
Vinayarani, G; Prakash, H S
Endophytic fungi have been isolated from the healthy turmeric (Curcuma longa L.) rhizomes from South India. Thirty-one endophytes were identified based on morphological and ITS-rDNA sequence analysis. The isolated endophytes were screened for antagonistic activity against Pythium aphanidermatum (Edson) Fitzp., and Rhizoctonia solani Kuhn., causing rhizome rot and leaf blight diseases in turmeric respectively. Results revealed that only six endophytes showed > 70% suppression of test pathogens in antagonistic dual culture assays. The endophyte T. harzianum TharDOB-31 showed significant in vitro mycelial growth inhibition of P. aphanidermatum (76.0%) and R. solani (76.9%) when tested by dual culture method. The SEM studies of interaction zone showed morphological abnormalities like parasitism, shriveling, breakage and lysis of hyphae of the pathogens by endophyte TharDOB-31. Selected endophytic isolates recorded multiple plant growth promoting traits in in vitro studies. The rhizome bacterization followed by soil application of endophyte TharDOB-31 showed lowest Percent Disease Incidence of rhizome rot and leaf blight, 13.8 and 11.6% respectively. The treatment of TharDOB-31 exhibited significant increase in plant height (85 cm) and fresh rhizome yield/plant (425 g) in comparison with untreated control under greenhouse condition. The confocal microscopy validates the colonization of the TharDOB-31 in turmeric rhizomes. The secondary metabolites in ethyl acetate extract of TharDOB-31 were found to contain higher number of antifungal compounds by high resolution liquid chromatograph mass spectrometer analysis. Thereby, endophyte T. harzianum isolate can be exploited as a potential biocontrol agent for suppressing rhizome rot and leaf blight diseases in turmeric.
Hennin, Caroline; Diederichsen, Elke; Höfte, Monica
summary In tomato and related species, the Cf9 resistance gene induces hypersensitive cell death and activates downstream defence pathways upon recognition of the Avr9 elicitor. We investigated whether the Cf9-Avr9 response without hypersensitive cell death symptoms increases resistance to several fungi. A low Avr9 dose that does not cause hypersensitive cell death was injected in Cf9 tomato and transgenic Cf9 oilseed rape plants. Subsequently, the injected leaves were infected with different fungal pathogens. The disease development of Botrytis cinerea was delayed in Cf9 tomato when the pathogen was inoculated on, or around, the Avr9 injection site. Disease development of Leptosphaeria maculans and Sclerotinia sclerotiorum was delayed on Cf9 oilseed rape plant parts located around the Avr9 injection site. Disease development of Oidium lycopersicum in Cf9 tomato or Erysiphe polygoni in Cf9 oilseed rape was not restricted on leaves injected with Avr9. The Avr9 injection induced systemic resistance to L. maculans and E. polygoni in Cf9 oilseed rape. F(1)(Cf9xAvr9) oilseed rape plants, obtained from crosses of transgenic Cf9x transgenic Avr9 oilseed rape, exhibited higher levels of resistance to L. maculans and E. polygoni but not to S. sclerotiorum, than wild-type plants. F(1)(Cf9xAvr9) plants treated with benzothiadiazole (BTH) did not show elevated levels of expression of some pathogenesis-related genes but developed higher levels of resistance to L. maculans than BTH-treated wild-type plants. This report demonstrates that the hypersensitive cell death which is associated with the Cf9-Avr9 response is not required for quantitative disease resistance.
Pierre J G M de Wit
Full Text Available We sequenced and compared the genomes of the Dothideomycete fungal plant pathogens Cladosporium fulvum (Cfu (syn. Passalora fulva and Dothistroma septosporum (Dse that are closely related phylogenetically, but have different lifestyles and hosts. Although both fungi grow extracellularly in close contact with host mesophyll cells, Cfu is a biotroph infecting tomato, while Dse is a hemibiotroph infecting pine. The genomes of these fungi have a similar set of genes (70% of gene content in both genomes are homologs, but differ significantly in size (Cfu >61.1-Mb; Dse 31.2-Mb, which is mainly due to the difference in repeat content (47.2% in Cfu versus 3.2% in Dse. Recent adaptation to different lifestyles and hosts is suggested by diverged sets of genes. Cfu contains an α-tomatinase gene that we predict might be required for detoxification of tomatine, while this gene is absent in Dse. Many genes encoding secreted proteins are unique to each species and the repeat-rich areas in Cfu are enriched for these species-specific genes. In contrast, conserved genes suggest common host ancestry. Homologs of Cfu effector genes, including Ecp2 and Avr4, are present in Dse and induce a Cf-Ecp2- and Cf-4-mediated hypersensitive response, respectively. Strikingly, genes involved in production of the toxin dothistromin, a likely virulence factor for Dse, are conserved in Cfu, but their expression differs markedly with essentially no expression by Cfu in planta. Likewise, Cfu has a carbohydrate-degrading enzyme catalog that is more similar to that of necrotrophs or hemibiotrophs and a larger pectinolytic gene arsenal than Dse, but many of these genes are not expressed in planta or are pseudogenized. Overall, comparison of their genomes suggests that these closely related plant pathogens had a common ancestral host but since adapted to different hosts and lifestyles by a combination of differentiated gene content, pseudogenization, and gene regulation.
Iven, Tim; König, Stefanie; Singh, Seema; Braus-Stromeyer, Susanna A; Bischoff, Matthias; Tietze, Lutz F; Braus, Gerhard H; Lipka, Volker; Feussner, Ivo; Dröge-Laser, Wolfgang
The soil-borne fungal pathogen Verticillium longisporum causes vascular disease on Brassicaceae host plants such as oilseed rape. The fungus colonizes the root xylem and moves upwards to the foliage where disease symptoms become visible. Using Arabidopsis as a model for early gene induction, we performed root transcriptome analyses in response to hyphal growth immediately after spore germination and during penetration of the root cortex, respectively. Infected roots showed a rapid reprogramming of gene expression such as activation of transcription factors, stress-, and defense-related genes. Here, we focused on the highly coordinated gene induction resulting in the production of tryptophan-derived secondary metabolites. Previous studies in leaves showed that enzymes encoded by CYP81F2 and PEN2 (PENETRATION2) execute the formation of antifungal indole glucosinolate (IGS) metabolites. In Verticillium-infected roots, we found transcriptional activation of CYP81F2 and the PEN2 homolog PEL1 (PEN2-LIKE1), but no increase in antifungal IGS breakdown products. In contrast, indole-3-carboxylic acid (I3CA) and the phytoalexin camalexin accumulated in infected roots but only camalexin inhibited Verticillium growth in vitro. Whereas genetic disruption of the individual metabolic pathways leading to either camalexin or CYP81F2-dependent IGS metabolites did not alter Verticillium-induced disease symptoms, a cyp79b2 cyp79b3 mutant impaired in both branches resulted in significantly enhanced susceptibility. Hence, our data provide an insight into root-specific early defenses and suggest tryptophan-derived metabolites as active antifungal compounds against a vascular pathogen.
de Wit, Pierre J. G. M.; van der Burgt, Ate; Okmen, Bilal; Stergiopoulos, Ioannis; Abd-Elsalam, Kamel A.; Aerts, Andrea L.; Bahkali, Ali H.; Beenen, Henriek G.; Chettri, Oranav; Cos, Murray P.; Datema, Erwin; de Vries, Ronald P.; DHillon, Braham; Ganley, Austen R.; Griffiths, Scott A.; Guo, Yanan; Gamelin, Richard C.; Henrissat, Bernard; Kabir, M. Shahjahan; Jashni, Mansoor Karimi; Kema, Gert; Klaubauf, Sylvia; Lapidus, Alla; Levasseur, Anthony; Lindquist, Erika; Mehrabi, Rahim; Ohm, Robin A.; Owen, Timothy J.; Salamov, Asaf; Schwelm, Arne; Schijlen, Elio; Sun, Hui; van den Burg, Harrold A.; van Burg, Roeland C. H. J.; Zhang, Shuguang; Goodwin, Stephen B.; Grigoriev, Igor V.; Collemare, Jerome; Bradshaw, Rosie E.
We sequenced and compared the genomes of the Dothideomycete fungal plant pathogens Cladosporium fulvum (Cfu) (syn. Passalora fulva) and Dothistroma septosporum (Dse) that are closely related phylogenetically, but have different lifestyles and hosts. Although both fungi grow extracellularly in close contact with host mesophyll cells, Cfu is a biotroph infecting tomato, while Dse is a hemibiotroph infecting pine. The genomes of these fungi have a similar set of genes (70percent of gene content in both genomes are homologs), but differ significantly in size (Cfu >61.1-Mb; Dse 31.2-Mb), which is mainly due to the difference in repeat content (47.2percent in Cfu versus 3.2percent in Dse). Recent adaptation to different lifestyles and hosts is suggested by diverged sets of genes. Cfu contains an tomatinase gene that we predict might be required for detoxification of tomatine, while this gene is absent in Dse. Many genes encoding secreted proteins are unique to each species and the repeat-rich areas in Cfu are enriched for these species-specific genes. In contrast, conserved genes suggest common host ancestry. Homologs of Cfu effector genes, including Ecp2 and Avr4, are present in Dse and induce a Cf-Ecp2- and Cf-4-mediated hypersensitive response, respectively. Strikingly, genes involved in production of the toxin dothistromin, a likely virulence factor for Dse, are conserved in Cfu, but their expression differs markedly with essentially no expression by Cfu in planta. Likewise, Cfu has a carbohydrate-degrading enzyme catalog that is more similar to that of necrotrophs or hemibiotrophs and a larger pectinolytic gene arsenal than Dse, but many of these genes are not expressed in planta or are pseudogenized. Overall, comparison of their genomes suggests that these closely related plant pathogens had a common ancestral host but since adapted to different hosts and lifestyles by a combination of differentiated gene content, pseudogenization, and gene regulation.
Miguel J Beltrán-García
Full Text Available In pathogenic fungi, melanin contributes to virulence, allowing tissue invasion and inactivation of the plant defence system, but has never been implicated as a factor for host cell death, or as a light-activated phytotoxin. Our research shows that melanin synthesized by the fungal banana pathogen Mycosphaerella fijiensis acts as a virulence factor through the photogeneration of singlet molecular oxygen O2 (1Δg. Using analytical tools, including elemental analysis, ultraviolet/infrared absorption spectrophometry and MALDI-TOF mass spectrometry analysis, we characterized both pigment content in mycelia and secreted to the culture media as 1,8-dihydroxynaphthalene (DHN-melanin type compound. This is sole melanin-type in M. fijiensis. Isolated melanins irradiated with a Nd:YAG laser at 532 nm produced monomol light emission at 1270 nm, confirming generation of O2 (1Δg, a highly reactive oxygen specie (ROS that causes cellular death by reacting with all cellular macromolecules. Intermediary polyketides accumulated in culture media by using tricyclazole and pyroquilon (two inhibitors of DHN-melanin synthesis were identified by ESI-HPLC-MS/MS. Additionally, irradiation at 532 nm of that mixture of compounds and whole melanized mycelium also generated O2 (1Δg. A pigmented-strain generated more O2 (1Δg than a strain with low melanin content. Banana leaves of cultivar Cavendish, naturally infected with different stages of black Sigatoka disease, were collected from field. Direct staining of the naturally infected leaf tissues showed the presence of melanin that was positively correlated to the disease stage. We also found hydrogen peroxide (H2O2 but we cannot distinguish the source. Our results suggest that O2 (1Δg photogenerated by DHN-melanin may be involved in the destructive effects of Mycosphaerella fijiensis on banana leaf tissues. Further studies are needed to fully evaluate contributions of melanin-mediated ROS to microbial pathogenesis.
Beltrán-García, Miguel J; Prado, Fernanda M; Oliveira, Marilene S; Ortiz-Mendoza, David; Scalfo, Alexsandra C; Pessoa, Adalberto; Medeiros, Marisa H G; White, James F; Di Mascio, Paolo
In pathogenic fungi, melanin contributes to virulence, allowing tissue invasion and inactivation of the plant defence system, but has never been implicated as a factor for host cell death, or as a light-activated phytotoxin. Our research shows that melanin synthesized by the fungal banana pathogen Mycosphaerella fijiensis acts as a virulence factor through the photogeneration of singlet molecular oxygen O2 (1Δg). Using analytical tools, including elemental analysis, ultraviolet/infrared absorption spectrophometry and MALDI-TOF mass spectrometry analysis, we characterized both pigment content in mycelia and secreted to the culture media as 1,8-dihydroxynaphthalene (DHN)-melanin type compound. This is sole melanin-type in M. fijiensis. Isolated melanins irradiated with a Nd:YAG laser at 532 nm produced monomol light emission at 1270 nm, confirming generation of O2 (1Δg), a highly reactive oxygen specie (ROS) that causes cellular death by reacting with all cellular macromolecules. Intermediary polyketides accumulated in culture media by using tricyclazole and pyroquilon (two inhibitors of DHN-melanin synthesis) were identified by ESI-HPLC-MS/MS. Additionally, irradiation at 532 nm of that mixture of compounds and whole melanized mycelium also generated O2 (1Δg). A pigmented-strain generated more O2 (1Δg) than a strain with low melanin content. Banana leaves of cultivar Cavendish, naturally infected with different stages of black Sigatoka disease, were collected from field. Direct staining of the naturally infected leaf tissues showed the presence of melanin that was positively correlated to the disease stage. We also found hydrogen peroxide (H2O2) but we cannot distinguish the source. Our results suggest that O2 (1Δg) photogenerated by DHN-melanin may be involved in the destructive effects of Mycosphaerella fijiensis on banana leaf tissues. Further studies are needed to fully evaluate contributions of melanin-mediated ROS to microbial pathogenesis.
Varela, José A; Otero, Luis; García, María José; Palacio, Virgilo; Carreño, Francisco; Cuesta, Mar; Sánchez, Carmen; Vázquez, Fernando
There are few studies of recent trends in the etiology and epidemiologic characteristics of specific microorganisms causing urethritis in men. The objective of the current study was to show the clinical experience in our country and to evaluate the trends in the prevalence of the pathogens in male urethritis, as well as the epidemiologic patterns in a series of 2101 patients. This was a descriptive study of the etiological agents causing urethritis in our sexually transmitted disease clinics in a period of 12 years (1989-2000), with a comparison of two periods of time. There were 97 cases of gonococcal urethritis (4.6%), 2004 of nongonococcal urethritis (95.4%), and 82 of mixed urethritis (3.9%). An association was found between gonococcal urethritis and heterosexual men; between chlamydial urethritis and homosexual/bisexual men; Ureaplasma urealyticum urethritis and heterosexual men and patients younger than 30 years of age; and between trichomonal urethritis and patients more than 30 years of age and the presence of HIV antibodies. During the period of research there was a significant decrease in cases of Neisseria gonorrhoeae and Chlamydia trachomatis urethritis and an increase in those of U urealyticum urethritis. In conclusion, this report describes changes in the etiology and epidemiologic patterns of urethritis in our country in recent years.
Full Text Available Coordination complexes with metal ions Cu(II, Ni(II, Co(II, Fe(III, Mn(II, Cr(III, and VO(II with six ligands formed by condensation products using azides and aldehydes or ketones are characterized. Both the ligands and the complexes synthesized are characterized by C, H, N, Cl and metal analyses, IR, UV-Vis, TGA, and magnetic susceptibility for tentative structure proposal. Several of them are screened for their toxicity (i.e., physiological activity against fungal species Rhizoctonia solani and Acrocylindrium oryzae and a bacterium, Xanthomonas oryzae on rice pathogens. The study shows that the observed physiological activity is enhanced for the metal complexes as compared to the simple metal salts or ligands, except in the case of L3 or HAEP ligand, where the free –OH and –NH2 groups on the ligand seemed to have inhibited the activity. It is also observed that the order of activity has a dependence on the increased atomic weight of the metal ion in use. In some cases, especially the VO(II complexes, they are found to be better than the standards in use, both for the fungicides and for the bactericide.
Gramaje, David; León, Maela; Santana, Marcela; Crous, Pedro W; Armengol, Josep
Cadophora luteo-olivacea is a lesser-known fungal trunk pathogen of grapevine which has been recently isolated from vines showing decline symptoms in grape growing regions worldwide. In this study, 80 C. luteo-olivacea isolates (65 from Spain and 15 from South Africa) were studied. Inter-simple-sequence repeat-polymerase chain reaction (ISSR-PCR) generated 55 polymorphic loci from four ISSR primers selected from an initial screen of 13 ISSR primers. The ISSR markers revealed 40 multilocus genotypes (MLGs) in the global population. Minimum spanning network analysis showed that the MLGs from South Africa clustered around the most frequent genotype, while the genotypes from Spain were distributed all across the network. Principal component analysis and dendrograms based on genetic distance and bootstrapping identified two highly differentiated genetic clusters in the Spanish and South African C. luteo-olivacea populations, with no intermediate genotypes between these clusters. Movement within the Spanish provinces may have occurred repeatedly given the frequent retrieval of the same genotype in distant locations. The results obtained in this study provide new insights into the population genetic structure of C. luteo-olivacea in Spain and highlights the need to produce healthy and quality planting material in grapevine nurseries to avoid the spread of this fungus throughout different grape growing regions.
Full Text Available Cadophora luteo-olivacea is a lesser-known fungal trunk pathogen of grapevine which has been recently isolated from vines showing decline symptoms in grape growing regions worldwide. In this study, 80 C. luteo-olivacea isolates (65 from Spain and 15 from South Africa were studied. Inter-simple-sequence repeat-polymerase chain reaction (ISSR-PCR generated 55 polymorphic loci from four ISSR primers selected from an initial screen of 13 ISSR primers. The ISSR markers revealed 40 multilocus genotypes (MLGs in the global population. Minimum spanning network analysis showed that the MLGs from South Africa clustered around the most frequent genotype, while the genotypes from Spain were distributed all across the network. Principal component analysis and dendrograms based on genetic distance and bootstrapping identified two highly differentiated genetic clusters in the Spanish and South African C. luteo-olivacea populations, with no intermediate genotypes between these clusters. Movement within the Spanish provinces may have occurred repeatedly given the frequent retrieval of the same genotype in distant locations. The results obtained in this study provide new insights into the population genetic structure of C. luteo-olivacea in Spain and highlights the need to produce healthy and quality planting material in grapevine nurseries to avoid the spread of this fungus throughout different grape growing regions.
Clergeot, Pierre-Henri; Gourgues, Mathieu; Cots, Joaquim; Laurans, F.; Latorse, Marie-Pascale; Pépin, Régis; Tharreau, Didier; Notteghem, Jean-Loup; Lebrun, Marc-Henri
We describe in this study punchless, a nonpathogenic mutant from the rice blast fungus M. grisea, obtained by plasmid-mediated insertional mutagenesis. As do most fungal plant pathogens, M. grisea differentiates an infection structure specialized for host penetration called the appressorium. We show that punchless differentiates appressoria that fail to breach either the leaf epidermis or artificial membranes such as cellophane. Cytological analysis of punchless appressoria shows that they have a cellular structure, turgor, and glycogen content similar to those of wild type before penetration, but that they are unable to differentiate penetration pegs. The inactivated gene, PLS1, encodes a putative integral membrane protein of 225 aa (Pls1p). A functional Pls1p-green fluorescent protein fusion protein was detected only in appressoria and was localized in plasma membranes and vacuoles. Pls1p is structurally related to the tetraspanin family. In animals, these proteins are components of membrane signaling complexes controlling cell differentiation, motility, and adhesion. We conclude that PLS1 controls an appressorial function essential for the penetration of the fungus into host leaves. PMID:11391010
Teixeira, Paulo José Pereira Lima; Thomazella, Daniela Paula de Toledo; Reis, Osvaldo; do Prado, Paula Favoretti Vital; do Rio, Maria Carolina Scatolin; Fiorin, Gabriel Lorencini; José, Juliana; Costa, Gustavo Gilson Lacerda; Negri, Victor Augusti; Mondego, Jorge Maurício Costa; Mieczkowski, Piotr; Pereira, Gonçalo Amarante Guimarães
Witches’ broom disease (WBD), caused by the hemibiotrophic fungus Moniliophthora perniciosa, is one of the most devastating diseases of Theobroma cacao, the chocolate tree. In contrast to other hemibiotrophic interactions, the WBD biotrophic stage lasts for months and is responsible for the most distinctive symptoms of the disease, which comprise drastic morphological changes in the infected shoots. Here, we used the dual RNA-seq approach to simultaneously assess the transcriptomes of cacao and M. perniciosa during their peculiar biotrophic interaction. Infection with M. perniciosa triggers massive metabolic reprogramming in the diseased tissues. Although apparently vigorous, the infected shoots are energetically expensive structures characterized by the induction of ineffective defense responses and by a clear carbon deprivation signature. Remarkably, the infection culminates in the establishment of a senescence process in the host, which signals the end of the WBD biotrophic stage. We analyzed the pathogen’s transcriptome in unprecedented detail and thereby characterized the fungal nutritional and infection strategies during WBD and identified putative virulence effectors. Interestingly, M. perniciosa biotrophic mycelia develop as long-term parasites that orchestrate changes in plant metabolism to increase the availability of soluble nutrients before plant death. Collectively, our results provide unique insight into an intriguing tropical disease and advance our understanding of the development of (hemi)biotrophic plant-pathogen interactions. PMID:25371547
Hefter, Maike; Lother, Jasmin; Weiß, Esther; Schmitt, Anna Lena; Fliesser, Mirjam; Einsele, Hermann; Loeffler, Juergen
Aspergillus fumigatus is an opportunistic fungal pathogen causing detrimental infections in immunocompromised individuals. Dendritic cells (DCs) are potent antigen-presenting cells and recognize the A. fumigatus cell wall component β-1,3 glucan via Dectin-1, followed by DC maturation and cytokine release. Here, we demonstrate that human primary myeloid DCs (mDCs) interact with different morphotypes of A. fumigatus. Dectin-1 is expressed on mDCs and is down-regulated after contact with A. fumigatus, indicating that mDCs recognize A. fumigatus via this receptor. Blocking of Dectin-1, followed by stimulation with depleted zymosan diminished the up-regulation of the T-cell co-stimulatory molecules CD40, CD80, HLA-DR and CCR7 on mDCs and led to decreased release of the cytokines TNF-α, IL-8, IL-1β and IL-10. © The Author 2016. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: firstname.lastname@example.org.
Full Text Available Oxylipins are fatty acid-derived signaling compounds produced by all eukaryotes so far investigated; in mycotoxigenic fungi, they modulate toxin production and interactions with the host plants. Among the many enzymes responsible for oxylipin generation, Linoleate Diol Synthase 1 (LDS1 produces mainly 8-hydroperoxyoctadecenoic acid and subsequently different di-hydroxyoctadecenoic acids. In this study, we inactivated a copy of the putative LDS1 ortholog (acc. N. FVEG_09294.3 of Fusarium verticillioides, with the aim to investigate its influence on the oxylipin profile of the fungus, on its development, secondary metabolism and virulence. LC-MS/MS oxylipin profiling carried out on the selected mutant strain revealed significant quali-quantitative differences for several oxylipins when compared to the WT strain. The Fvlds1-deleted mutant grew better, produced more conidia, synthesized more fumonisins and infected maize cobs faster than the WT strain. We hypothesize that oxylipins may act as regulators of gene expression in the toxigenic plant pathogen F. verticillioides, in turn causing notable changes in its phenotype. These changes could relate to the ability of oxylipins to re-shape the transcriptional profile of F. verticillioides by inducing chromatin modifications and exerting a direct control on the transcription of secondary metabolism in fungi.
Scala, Valeria; Giorni, Paola; Cirlini, Martina; Ludovici, Matteo; Visentin, Ivan; Cardinale, Francesca; Fabbri, Anna A.; Fanelli, Corrado; Reverberi, Massimo; Battilani, Paola; Galaverna, Gianni; Dall'Asta, Chiara
Oxylipins are fatty acid-derived signaling compounds produced by all eukaryotes so far investigated; in mycotoxigenic fungi, they modulate toxin production and interactions with the host plants. Among the many enzymes responsible for oxylipin generation, Linoleate Diol Synthase 1 (LDS1) produces mainly 8-hydroperoxyoctadecenoic acid and subsequently different di-hydroxyoctadecenoic acids. In this study, we inactivated a copy of the putative LDS1 ortholog (acc. N. FVEG_09294.3) of Fusarium verticillioides, with the aim to investigate its influence on the oxylipin profile of the fungus, on its development, secondary metabolism and virulence. LC-MS/MS oxylipin profiling carried out on the selected mutant strain revealed significant quali-quantitative differences for several oxylipins when compared to the WT strain. The Fvlds1-deleted mutant grew better, produced more conidia, synthesized more fumonisins and infected maize cobs faster than the WT strain. We hypothesize that oxylipins may act as regulators of gene expression in the toxigenic plant pathogen F. verticillioides, in turn causing notable changes in its phenotype. These changes could relate to the ability of oxylipins to re-shape the transcriptional profile of F. verticillioides by inducing chromatin modifications and exerting a direct control on the transcription of secondary metabolism in fungi. PMID:25566199
DiGuistini, Scott; Wang, Ye; Liao, Nancy Y; Taylor, Greg; Tanguay, Philippe; Feau, Nicolas; Henrissat, Bernard; Chan, Simon K; Hesse-Orce, Uljana; Alamouti, Sepideh Massoumi; Tsui, Clement K M; Docking, Roderick T; Levasseur, Anthony; Haridas, Sajeet; Robertson, Gordon; Birol, Inanc; Holt, Robert A; Marra, Marco A; Hamelin, Richard C; Hirst, Martin; Jones, Steven J M; Bohlmann, Jörg; Breuil, Colette
In western North America, the current outbreak of the mountain pine beetle (MPB) and its microbial associates has destroyed wide areas of lodgepole pine forest, including more than 16 million hectares in British Columbia. Grosmannia clavigera (Gc), a critical component of the outbreak, is a symbiont of the MPB and a pathogen of pine trees. To better understand the interactions between Gc, MPB, and lodgepole pine hosts, we sequenced the ∼30-Mb Gc genome and assembled it into 18 supercontigs. We predict 8,314 protein-coding genes, and support the gene models with proteome, expressed sequence tag, and RNA-seq data. We establish that Gc is heterothallic, and report evidence for repeat-induced point mutation. We report insights, from genome and transcriptome analyses, into how Gc tolerates conifer-defense chemicals, including oleoresin terpenoids, as they colonize a host tree. RNA-seq data indicate that terpenoids induce a substantial antimicrobial stress in Gc, and suggest that the fungus may detoxify these chemicals by using them as a carbon source. Terpenoid treatment strongly activated a ∼100-kb region of the Gc genome that contains a set of genes that may be important for detoxification of these host-defense chemicals. This work is a major step toward understanding the biological interactions between the tripartite MPB/fungus/forest system.
Lerm, Barbra; Kenyon, Chris; Schwartz, Ilan S; Kroukamp, Heinrich; de Witt, Riaan; Govender, Nelesh P; de Hoog, G Sybren; Botha, Alfred
Cryptococcus neoformans is an opportunistic pathogen responsible for the AIDS-defining illness, cryptococcal meningitis. During the disease process, entry of cryptococcal cells into the brain is facilitated by virulence factors that include urease enzyme activity. A novel species of an Emmonsia-like fungus, recently named Emergomyces africanus, was identified as a cause of disseminated mycosis in HIV-infected persons in South Africa. However, in contrast to C. neoformans, the enzymes produced by this fungus, some of which may be involved in pathogenesis, have not been described. Using a clinical isolate of C. neoformans as a reference, the study aim was to confirm, characterise and quantify urease activity in E. africanus clinical isolates. Urease activity was tested using Christensen's urea agar, after which the presence of a urease gene in the genome of E. africanus was confirmed using gene sequence analysis. Subsequent evaluation of colorimetric enzyme assay data, using Michaelis-Menten enzyme kinetics, revealed similarities between the substrate affinity of the urease enzyme produced by E. africanus (Km ca. 26.0 mM) and that of C. neoformans (Km ca. 20.6 mM). However, the addition of 2.5 g/l urea to the culture medium stimulated urease activity of E. africanus, whereas nutrient limitation notably increased cryptococcal urease activity. © FEMS 2017. All rights reserved. For permissions, please e-mail: email@example.com.
Lewis, David A; Chirwa, Tobias F; Msimang, Veerle M Y; Radebe, Frans M; Kamb, Mary L; Firnhaber, Cynthia S
To determine sexually transmitted infection (STI) prevalence, and patient characteristics associated with detection of urethritis/cervicitis pathogens, among HIV-infected individuals offered voluntary STI screening at a South African HIV treatment center. Individuals, asymptomatic for genital discharge, were screened for Neisseria gonorrhoeae (NG), Chlamydia trachomatis, Trichomonas vaginalis (TV), Mycoplasma genitalium (MG) infections (real-time polymerase chain reaction assay), for syphilis and herpes simplex type 2 (serologically), and for bacterial vaginosis and Candida (microscopy, women only). Patients' most recent CD4 and viral load results were recorded. Demographic, clinical, and behavioral data were collected by nurse-administered questionnaire. Compared with men (n = 551), women (n = 558) were younger (mean age, 35.0 vs. 37.9 years; P urethritis/cervicitis pathogens detected (21.3% vs.16.4%, P = 0.035), and were less aware of their partner's HIV status (53.1% vs. 62.3%; P = 0.007). The overall prevalence of individual urethritis/cervicitis pathogens was TV (7.6%), MG (6.1%), NG (5.4%), and C. trachomatis (2.1%). Multivariate analysis highlighted 4 significant factors associated with the detection of specific urethritis/cervicitis pathogens, namely female gender (TV, adjusted odds ratio [aOR] 2.53, 95% confidence interval [CI]: 1.47-4.37), having a regular sexual partner in the past 3 months (NG, aOR 2.26, 95% CI: 1.01-5.08), suboptimal condom use with regular partners (TV, aOR 2.07, 95% CI: 1.25-3.42), and a history of genital warts in the past year (NG, 2.25, 95% CI: 1.26-4.03). Asymptomatic urethritis/cervicitis pathogens were highly prevalent in this population. Few urethritis/cervicitis pathogen-associated patient characteristics were identified, emphasizing the need for affordable STI diagnostics to screen HIV-infected patients.
Vanantwerpen, Gerty; Van Damme, Inge; De Zutter, Lieven; Houf, Kurt
Yersiniosis is a common bacterial zoonosis in Europe and healthy pigs are known to be the primary reservoir of human pathogenic Yersinia enterocolitica and Y. pseudotuberculosis. However, little information is available about the prevalence of these pathogens within pig batches at time of slaughter. The tonsils of 7047 fattening pigs, belonging to 100 farms, were aseptically collected immediately after evisceration in two Belgian slaughterhouses. The batch size varied between 70 and 930 pigs. On average, 70 pigs were sampled per batch. The tonsils were examined by direct plating on cefsulodin-irgasan-novobiocin (CIN) agar plates and the number of suspect Yersinia colonies was counted. Pathogenic Y. enterocolitica serotype O:3 were found in tonsils of 2009 pigs (28.5%), originating from 85 farms. The within-batch prevalence in positive farms ranged from 5.1 to 64.4%. The number of Y. enterocolitica in positive pigs varied between 2.01 and 5.98 log10 CFU g(-1) tonsil, with an average of 4.00 log10 CFU g(-1) tonsil. Y. pseudotuberculosis was found in seven farms, for which the within-batch prevalence varied from 2 to 10%. In five of these farms, both Y. enterocolitica and Y. pseudotuberculosis were simultaneously present. Human pathogenic Yersinia spp. are widespread in slaughter pig batches in Belgium as 87% of the tested batches were infected with these pathogens at the time of slaughter. The large variation of the prevalence between batches may lead to different levels of contamination of carcasses and risks for public health. Copyright © 2014 Elsevier B.V. All rights reserved.
Lars Matthias Voll
Full Text Available During compatible interactions with their host plants, biotrophic plant pathogens subvert host metabolism to ensure the sustained provision of nutrient assimilates by the colonized host cells. To investigate, whether common motifs can be revealed in the response of primary carbon and nitrogen metabolism towards colonization with biotrophic fungi in cereal leaves, we have conducted a combined metabolome and transcriptome study of three quite divergent pathosystems, the barley powdery mildew fungus (Blumeria graminis f.sp. hordei, the corn smut fungus Ustilago maydis and the maize anthracnose fungus Colletotrichum graminicola, the latter being a hemibiotroph that only exhibits an initial biotrophic phase during its establishment.Based on the analysis of 42 water-soluble metabolites, we were able to separate early biotrophic from late biotrophic interactions by hierarchical cluster analysis and principal component analysis, irrespective of the plant host. Interestingly, the corresponding transcriptome dataset could not discriminate between these stages of biotrophy, irrespective, of whether transcript data for genes of central metabolism or the entire transcriptome dataset was used. Strong differences in the transcriptional regulation of photosynthesis, glycolysis, the TCA cycle, lipid biosynthesis, and cell wall metabolism were observed between the pathosystems. Increased contents of Gln, Asn, and glucose as well as diminished contents of PEP and 3-PGA were common to early post-penetration stages of all interactions. On the transcriptional level, genes of the TCA cycle, nucleotide energy metabolism and amino acid biosynthesis exhibited consistent trends among the compared biotrophic interactions, identifying the requirement for metabolic energy and the rearrangement of amino acid pools as common transcriptional motifs during early biotrophy. Both metabolome and transcript data were employed to generate models of leaf primary metabolism during
Voll, Lars Matthias; Horst, Robin Jonathan; Voitsik, Anna-Maria; Zajic, Doreen; Samans, Birgit; Pons-Kühnemann, Jörn; Doehlemann, Gunther; Münch, Steffen; Wahl, Ramon; Molitor, Alexandra; Hofmann, Jörg; Schmiedl, Alfred; Waller, Frank; Deising, Holger Bruno; Kahmann, Regine; Kämper, Jörg; Kogel, Karl-Heinz; Sonnewald, Uwe
During compatible interactions with their host plants, biotrophic plant–pathogens subvert host metabolism to ensure the sustained provision of nutrient assimilates by the colonized host cells. To investigate, whether common motifs can be revealed in the response of primary carbon and nitrogen metabolism toward colonization with biotrophic fungi in cereal leaves, we have conducted a combined metabolome and transcriptome study of three quite divergent pathosystems, the barley powdery mildew fungus (Blumeria graminis f.sp. hordei), the corn smut fungus Ustilago maydis, and the maize anthracnose fungus Colletotrichum graminicola, the latter being a hemibiotroph that only exhibits an initial biotrophic phase during its establishment. Based on the analysis of 42 water-soluble metabolites, we were able to separate early biotrophic from late biotrophic interactions by hierarchical cluster analysis and principal component analysis, irrespective of the plant host. Interestingly, the corresponding transcriptome dataset could not discriminate between these stages of biotrophy, irrespective, of whether transcript data for genes of central metabolism or the entire transcriptome dataset was used. Strong differences in the transcriptional regulation of photosynthesis, glycolysis, the TCA cycle, lipid biosynthesis, and cell wall metabolism were observed between the pathosystems. However, increased contents of Gln, Asn, and glucose as well as diminished contents of PEP and 3-PGA were common to early post-penetration stages of all interactions. On the transcriptional level, genes of the TCA cycle, nucleotide energy metabolism and amino acid biosynthesis exhibited consistent trends among the compared biotrophic interactions, identifying the requirement for metabolic energy and the rearrangement of amino acid pools as common transcriptional motifs during early biotrophy. Both metabolome and transcript data were employed to generate models of leaf primary metabolism during early
have discovered a novel protein involved in the virulence of both plant and animal fungal pathogens. Our results strongly suggest that dysregulation of oxidative stress homeostasis in the absence of TmpL is the underpinning cause of the developmental and virulence defects observed in these studies.
Ceresini, Paulo C. [UNESP; Costa-Souza, Elaine [UNESP; Zala, Marcello; Furtado, Edson Luiz [UNESP; Souza, Nilton L. [UNESP
The white-thread blight and black rot (WTBR) caused by basidiomycetous fungi of the genus Ceratobasidium is emerging as an important plant disease in Brazil, particularly for crop species in the Ericales such as persimmon (Diospyros kaki) and tea (Camellia sinensis). However, the species identity of the fungal pathogen associated with either of these hosts is still unclear. In this work, we used sequence variation in the internal transcribed spacer regions, including the 5.8S coding region of...
Jesse S Lewis
Full Text Available Transmission of pathogens among animals is influenced by demographic, social, and environmental factors. Anthropogenic alteration of landscapes can impact patterns of disease dynamics in wildlife populations, increasing the potential for spillover and spread of emerging infectious diseases in wildlife, human, and domestic animal populations. We evaluated the effects of multiple ecological mechanisms on patterns of pathogen exposure in animal populations. Specifically, we evaluated how ecological factors affected the prevalence of Toxoplasma gondii (Toxoplasma, Bartonella spp. (Bartonella, feline immunodeficiency virus (FIV, and feline calicivirus (FCV in bobcat and puma populations across wildland-urban interface (WUI, low-density exurban development, and wildland habitat on the Western Slope (WS and Front Range (FR of Colorado during 2009-2011. Samples were collected from 37 bobcats and 29 pumas on the WS and FR. As predicted, age appeared to be positively related to the exposure to pathogens that are both environmentally transmitted (Toxoplasma and directly transmitted between animals (FIV. In addition, WS bobcats appeared more likely to be exposed to Toxoplasma with increasing intraspecific space-use overlap. However, counter to our predictions, exposure to directly-transmitted pathogens (FCV and FIV was more likely with decreasing space-use overlap (FCV: WS bobcats and potential intraspecific contacts (FIV: FR pumas. Environmental factors, including urbanization and landscape covariates, were generally unsupported in our models. This study is an approximation of how pathogens can be evaluated in relation to demographic, social, and environmental factors to understand pathogen exposure in wild animal populations.
Logan, Kenneth A.; Alldredge, Mat W.; Carver, Scott; Bevins, Sarah N.; Lappin, Michael; VandeWoude, Sue; Crooks, Kevin R.
Transmission of pathogens among animals is influenced by demographic, social, and environmental factors. Anthropogenic alteration of landscapes can impact patterns of disease dynamics in wildlife populations, increasing the potential for spillover and spread of emerging infectious diseases in wildlife, human, and domestic animal populations. We evaluated the effects of multiple ecological mechanisms on patterns of pathogen exposure in animal populations. Specifically, we evaluated how ecological factors affected the prevalence of Toxoplasma gondii (Toxoplasma), Bartonella spp. (Bartonella), feline immunodeficiency virus (FIV), and feline calicivirus (FCV) in bobcat and puma populations across wildland-urban interface (WUI), low-density exurban development, and wildland habitat on the Western Slope (WS) and Front Range (FR) of Colorado during 2009–2011. Samples were collected from 37 bobcats and 29 pumas on the WS and FR. As predicted, age appeared to be positively related to the exposure to pathogens that are both environmentally transmitted (Toxoplasma) and directly transmitted between animals (FIV). In addition, WS bobcats appeared more likely to be exposed to Toxoplasma with increasing intraspecific space-use overlap. However, counter to our predictions, exposure to directly-transmitted pathogens (FCV and FIV) was more likely with decreasing space-use overlap (FCV: WS bobcats) and potential intraspecific contacts (FIV: FR pumas). Environmental factors, including urbanization and landscape covariates, were generally unsupported in our models. This study is an approximation of how pathogens can be evaluated in relation to demographic, social, and environmental factors to understand pathogen exposure in wild animal populations. PMID:29121060
Corinne P. Oechslin
Full Text Available Abstract Background Throughout Europe, Ixodes ricinus transmits numerous pathogens. Its widespread distribution is not limited to rural but also includes urbanized areas. To date, comprehensive data on pathogen carrier rates of I. ricinus ticks in urban areas of Switzerland is lacking. Results Ixodes ricinus ticks sampled at 18 (sub- urban collection sites throughout Switzerland showed carrier rates of 0% for tick-borne encephalitis virus, 18.0% for Borrelia burgdorferi (sensu lato, 2.5% for Borrelia miyamotoi, 13.5% for Rickettsia spp., 1.4% for Anaplasma phagocytophilum, 6.2% for "Candidatus Neoehrlichia mikurensis", and 0.8% for Babesia venatorum (Babesia sp., EU1. Site-specific prevalence at collection sites with n > 45 ticks (n = 9 significantly differed for B. burgdorferi (s.l., Rickettsia spp., and "Ca. N. mikurensis", but were not related to the habitat type. Three hundred fifty eight out of 1078 I. ricinus ticks (33.2% tested positive for at least one pathogen. Thereof, about 20% (71/358 were carrying two or three different potentially disease-causing agents. Using next generation sequencing, we could detect true pathogens, tick symbionts and organisms of environmental or human origin in ten selected samples. Conclusions Our data document the presence of pathogens in the (sub- urban I. ricinus tick population in Switzerland, with carrier rates as high as those in rural regions. Carriage of multiple pathogens was repeatedly observed, demonstrating the risk of acquiring multiple infections as a consequence of a tick bite.
Saffell, Brandy J; Meinzer, Frederick C; Voelker, Steven L; Shaw, David C; Brooks, J Renée; Lachenbruch, Barbara; McKay, Jennifer
Swiss needle cast (SNC) is a fungal disease of Douglas-fir (Pseudotsuga menziesii) that has recently become prevalent in coastal areas of the Pacific Northwest. We used growth measurements and stable isotopes of carbon and oxygen in tree-rings of Douglas-fir and a non-susceptible reference species (western hemlock, Tsuga heterophylla) to evaluate their use as proxies for variation in past SNC infection, particularly in relation to potential explanatory climate factors. We sampled trees from an Oregon site where a fungicide trial took place from 1996 to 2000, which enabled the comparison of stable isotope values between trees with and without disease. Carbon stable isotope discrimination (Δ(13)C) of treated Douglas-fir tree-rings was greater than that of untreated Douglas-fir tree-rings during the fungicide treatment period. Both annual growth and tree-ring Δ(13)C increased with treatment such that treated Douglas-fir had values similar to co-occurring western hemlock during the treatment period. There was no difference in the tree-ring oxygen stable isotope ratio between treated and untreated Douglas-fir. Tree-ring Δ(13)C of diseased Douglas-fir was negatively correlated with relative humidity during the two previous summers, consistent with increased leaf colonization by SNC under high humidity conditions that leads to greater disease severity in following years. © 2013 John Wiley & Sons Ltd.
Yash Pal Chugh
Full Text Available The present study was conducted to find out the prevalence and spectrum of Gram negative pathogens causing bacterial meningitis and their antimicrobial susceptibility pattern in a tertiary care hospital. The cerebrospinal fluid (CSF (3-5 ml was collected from 638 admitted children clinically suspected of septic meningitis. Bacterial isolates were identified and antimicrobial susceptibility was assessed by the Kirby-Bauer disk diffusion method. Of the 638 samples tested 102 (15.99% were culture positive. Male to female (M:F ratio was 1.62:1. The maximum incidence of 45 (44.12% cases was found in children (1-12 yrs; in institutional deliveries the incidence was 58 (56.86% cases. Further, the incidence of 51 cases was found from May to August. Escherichia coli (E. coli were commonest, seen in 9 (25% cases followed by Acinetobacter spp., Citrobacter spp. and Klebsiella spp. with 6 (16.67% cases each. Enterobacter spp., Neisseria spp. and Pseudomonas aeruginosa were isolated in 3 (8.33% cases each. E. coli, Acinetobacter spp, Citrobacter spp and Klebsiella spp isolates were 100% susceptible to meropenem, piperacillin-tazobactam and cefoperazone-sulbactam and 100% resistant to cotrimoxazole and tetracycline. All strains of Neisseria spp, Enterobacter spp and Pseudomonas spp. were 100% susceptible to meropenem followed by gatifloxacin. These were 100% resistant to tetracycline and cotrimoxazole. Neisseria spp. were also 100% susceptible to pristinamycin. In septic meningitis Gram negative organisms are less common (35.29%. Of the isolates, more common Gram negative isolates included E. coli, Acinetobacter Spp., Citrobacter Spp., and Klebsiella spp. and these isolates were 100% susceptible to meropenem, piperacillin-tazobacatam and cefoperazone-sulbactam. Hence, empirical therapy should be formulated according to antimicrobial susceptibility patterns.
Kofoed, Kristian; Zalounina, Alina; Andersen, Ove
OBJECTIVES: To evaluate a decision support system (TREAT) for guidance of empirical antimicrobial therapy in an environment with a low prevalence of resistant pathogens. METHODS: A retrospective trial of TREAT has been performed at Copenhagen University, Hvidovre Hospital. The cohort of patients......, 161 (65 with microbiologically documented infections) fulfilled the inclusion criteria of TREAT. Coverage achieved by TREAT was significantly higher than that by clinical practice (86% versus 66%, P = 0.007). There was no significant difference in the cost of future resistance between treatments...... of the study suggest that TREAT can improve the appropriateness of antimicrobial therapy and reduce the cost of side effects in regions with a low prevalence of resistant pathogens, however, at the expense of increased use of antibiotics....
Cashdan, Elizabeth; Steele, Matthew
It has been argued that people in areas with high pathogen loads will be more likely to avoid outsiders, to be biased in favor of in-groups, and to hold collectivist and conformist values. Cross-national studies have supported these predictions. In this paper we provide new pathogen codes for the 186 cultures of the Standard Cross-Cultural Sample and use them, together with existing pathogen and ethnographic data, to try to replicate these cross-national findings. In support of the theory, we found that cultures in high pathogen areas were more likely to socialize children toward collectivist values (obedience rather than self-reliance). There was some evidence that pathogens were associated with reduced adult dispersal. However, we found no evidence of an association between pathogens and our measures of group bias (in-group loyalty and xenophobia) or intergroup contact.
Wetmore, Catherine M; Manhart, Lisa E; Golden, Matthew R
Urethritis is the most common male reproductive tract disease syndrome; yet 20-50% of diagnosed cases have no defined etiology, and few population-level data exist on the prevalence or etiology of the syndrome. We estimated the prevalence of urethritis among young men in the United States and compared correlates of idiopathic cases to correlates of detected infections with sexually transmitted pathogens. Questionnaire data and urine specimens from 5,447 men aged 18-27 years participating in Wave III of the National Longitudinal Study of Adolescent Health were analyzed. Symptomatic urethritis was defined as self-reported dysuria or urethral discharge in the past 24hours. Neisseria gonorrhoeae, Chlamydia trachomatis, Trichomonas vaginalis, and Mycoplasma genitalium were identified using nucleic acid amplification tests. Idiopathic urethritis (IU) was defined as urethral symptoms in the absence of these four pathogens. Stratified weighted analyses generated population-based estimates. Urethritis was reported by 1.2% (95% CI=.8-1.6%) of men, of whom 82.4% (61.1-93.3%) had IU. Men with previous STD diagnoses (aOR=9.3 [95% CI=3.0-28.7]), or fewer (1-4) or no lifetime vaginal sex partners (aOR=7.5 [2.9-19.3] and aOR=7.2 [1.9-27.4]), were more likely to have IU compared with men without urethral symptoms or identified pathogens, whereas men of Native American or Asian/Pacific Islander descent (aOR=.04 [.01-.2]) and heavy drinkers (aOR=.08 [.03-.2]) were less likely to have IU. Unlike infection with known pathogens, IU was not associated with black race, Hispanic ethnicity, or age at sexual debut. Urethral symptoms were rarely associated with known pathogens. IU and known pathogens were associated with distinct characteristics.
Díaz-López, A; Cantú-Ramírez, R C; Garza-González, E; Ruiz-Tolentino, L; Tellez-Luis, S J; Rivera, G; Bocanegra-García, V
We analyzed a total of 70 grilled chicken samples bought randomly from street vendors and retail outlets in the city of Reynosa, Mexico, to determine the prevalence of Escherichia coli (Shiga toxin producing and enterotoxin producing), Salmonella spp., Staphylococcus aureus, Listeria spp., and Campylobacter spp. using microbiological methods and PCR detection of bacterial sequences. Of the 70 samples, 27 (38.5%) were from retail outlets and 43 (61.4%) from street vendors. All specimens were negative by both microbiological and molecular methods for Listeria monocytogenes, Shiga toxin 2 of Shiga toxin-producing E. coli, lt of enterotoxin-producing E. coli, and st enterotoxin, and all were negative for Salmonella spp. and Campylobacter jejuni by PCR. Of the samples studied, 49 (70%) had undetectable levels of the foodborne pathogens studied with the methods used. In the remaining 21 (30%) specimens, at least one pathogen was isolated or detected, with E. coli being the pathogen most frequently isolated and with two samples bearing the hlyA gene. We found no statistical difference in bacterial prevalence between retail and street vendor samples. The presence of pathogens in grilled chicken is an important public health risk because of the great demand for and daily consumption of this product in this region.
Ana M. Pinheiro
Full Text Available The lack of antifungal drugs with novel modes of action reaching the clinic is a serious concern. Recently a novel antifungal protein referred to as Blad-containing oligomer (BCO has received regulatory approval as an agricultural antifungal agent. Interestingly its spectrum of antifungal activity includes human pathogens such as Candida albicans, however, its mode of action has yet to be elucidated. Here we demonstrate that BCO exerts its antifungal activity through inhibition of metal ion homeostasis which results in apoptotic cell death in C. albicans. HIP HOP profiling in Saccharomyces cerevisiae using a panel of signature strains that are characteristic for common modes of action identified hypersensitivity in yeast lacking the iron-dependent transcription factor Aft1 suggesting restricted iron uptake as a mode of action. Furthermore, global transcriptome profiling in C. albicans also identified disruption of metal ion homeostasis as a potential mode of action. Experiments were carried out to assess the effect of divalent metal ions on the antifungal activity of BCO revealing that BCO activity is antagonized by metal ions such as Mn2+, Zn2+, and Fe2+. The transcriptome profile also implicated sterol synthesis as a possible secondary mode of action which was subsequently confirmed in sterol synthesis assays in C. albicans. Animal models for toxicity showed that BCO is generally well tolerated and presents a promising safety profile as a topical applied agent. Given its potent broad spectrum antifungal activity and novel multitarget mode of action, we propose BCO as a promising new antifungal agent for the topical treatment of fungal infections.
The invention relates to control of fungal foliar diseases in plants, preferaby Rosaceae, such as apple scab (Venturia inaequalis), pear scab (Venturia pirina), brown spot (Stemphylium vesicarium) and powdery mildew (Podosphaera leucotricha) by treatment of plant with an extract of Yucca species......, preferably Y. schidigera or Y. filamentosa. The treatment is effective in both prevention and treatment of the fungal infection....
Halos, Lénaïg; Bord, Séverine; Cotté, Violaine; Gasqui, Patrick; Abrial, David; Barnouin, Jacques; Boulouis, Henri-Jean; Vayssier-Taussat, Muriel; Vourc'h, Gwenaël
Ecological changes are recognized as an important driver behind the emergence of infectious diseases. The prevalence of infection in ticks depends upon ecological factors that are rarely taken into account simultaneously. Our objective was to investigate the influences of forest fragmentation, vegetation, adult tick hosts, and habitat on the infection prevalence of three tick-borne bacteria, Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum, and Rickettsia sp. of the spotted fever group, in questing Ixodes ricinus ticks, taking into account tick characteristics. Samples of questing nymphs and adults were taken from 61 pastures and neighboring woodlands in central France. The ticks were tested by PCR of pools of nymphs and individual adults. The individual infection prevalence was modeled using multivariate regression. The highest infection prevalences were found in adult females collected in woodland sites for B. burgdorferi sensu lato and A. phagocytophilum (16.1% and 10.7%, respectively) and in pasture sites for Rickettsia sp. (8.7%). The infection prevalence in nymphs was lower than 6%. B. burgdorferi sensu lato was more prevalent in woodlands than in pastures. Forest fragmentation favored B. burgdorferi sensu lato and A. phagocytophilum prevalence in woodlands, and in pastures, the B. burgdorferi sensu lato prevalence was favored by shrubby vegetation. Both results are probably because large amounts of edges or shrubs increase the abundance of small vertebrates as reservoir hosts. The Rickettsia sp. prevalence was maximal on pasture with medium forest fragmentation. Female ticks were more infected by B. burgdorferi sensu lato than males and nymphs in woodland sites, which suggests an interaction between the ticks and the bacteria. This study confirms the complexity of the tick-borne pathogen ecology. The findings support the importance of small vertebrates as reservoir hosts and make a case for further studies in Europe on the link between the
Truong, Quang Lam; Seo, Tae Won; Yoon, Byung-Il; Kim, Hyeon-Cheol; Han, Jeong Hee; Hahn, Tae-Wook
In 2008, 102 rodents and 24 stray cats from the areas around 9 pig farms in northeast South Korea were used to determine the prevalence of the following selected swine pathogens: ten viral pathogens [porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis virus (TGEV), rotavirus, classical swine fever virus (CSFV), porcine circovirus type 2 (PCV2), encephalomyocarditis virus (EMCV), porcine reproductive and respiratory syndrome virus (PRRSV), porcine parvovirus (PPV), pseudorabies virus (PRV) and Japanese encephalitis virus (JEV)] and four bacterial pathogens (Brucella, Leptospira, Salmonella and Lawsonia intracellularis). In total, 1,260 tissue samples from 102 rodents and 24 stray cats were examined by specific PCR and RT-PCR assays, including tissue samples of the brain, tonsils, lungs, heart, liver, kidneys, spleen, small intestine, large intestine and mesenteric lymph nodes. The percentages of PCR-positive rodents for the porcine pathogens were as follows: 63.7% for Leptospira, 39.2% for Brucella, 6.8% for Salmonella, 15.7% for L. intracellularis, 14.7% for PCV2 and 3.9% for EMCV. The percentages of PCR-positive stray cats for the swine pathogens were as follows: 62.5% for Leptospira, 25% for Brucella, 12.5% for Salmonella, 12.5% for L. intracellularis and 4.2% for PEDV. These results may be helpful for developing control measures to prevent the spread of infectious diseases of pigs.
Grigoriev, Igor V.
Genomes of energy and environment fungi are in focus of the Fungal Genomic Program at the US Department of Energy Joint Genome Institute (JGI). Its key project, the Genomics Encyclopedia of Fungi, targets fungi related to plant health (symbionts, pathogens, and biocontrol agents) and biorefinery processes (cellulose degradation, sugar fermentation, industrial hosts), and explores fungal diversity by means of genome sequencing and analysis. Over 50 fungal genomes have been sequenced by JGI to date and released through MycoCosm (www.jgi.doe.gov/fungi), a fungal web-portal, which integrates sequence and functional data with genome analysis tools for user community. Sequence analysis supported by functional genomics leads to developing parts list for complex systems ranging from ecosystems of biofuel crops to biorefineries. Recent examples of such 'parts' suggested by comparative genomics and functional analysis in these areas are presented here
Gras, J R; Lafarga, J; Ronda, J M; Trigueros, M; Sancho, M; Aracil, A
Allergic fungal sinusitis is a recently described clinical entity that has gained increased attention as a cause of chronic sinusitis. Consist in a benign noninvasive sinus disease related to a hypersensitivity reaction to fungal antigens. It should be suspected in any atopic patient with refractory nasal polyps. Computed tomography (CT) findings are characteristics, but not diagnostic. Diagnosis requires show allergic mucin in the histopathologic examination and hiphae in special fungal stains. The suitable treatment includes the allergic mucin removal and sinus aeration accomplished endoscopically, perioperative systemic steroids and immunotherapy with fungal antigens. We present a case of this kind of chronic sinusitis describing the characteristic histopathologic and radiologic findings, the pathogenic theories and recent advances in immunotherapy.
Garcia-Solache, Monica A.; Casadevall, Arturo
ABSTRACT Fungi are major pathogens of plants, other fungi, rotifers, insects, and amphibians, but relatively few cause disease in mammals. Fungi became important human pathogens only in the late 20th century, primarily in hosts with impaired immunity as a consequence of medical interventions or HIV infection. The relatively high resistance of mammals has been attributed to a combination of a complex immune system and endothermy. Mammals maintain high body temperatures relative to environmental temperatures, creating a thermally restrictive ambient for the majority of fungi. According to this view, protection given by endothermy requires a temperature gradient between those of mammals and the environment. We hypothesize that global warming will increase the prevalence of fungal diseases in mammals by two mechanisms: (i) increasing the geographic range of currently pathogenic species and (ii) selecting for adaptive thermotolerance for species with significant pathogenic potential but currently not pathogenic by virtue of being restricted by mammalian temperatures. PMID:20689745
The JGI Fungal Genomics Program aims to scale up sequencing and analysis of fungal genomes to explore the diversity of fungi important for energy and the environment, and to promote functional studies on a system level. Combining new sequencing technologies and comparative genomics tools, JGI is now leading the world in fungal genome sequencing and analysis. Over 120 sequenced fungal genomes with analytical tools are available via MycoCosm (www.jgi.doe.gov/fungi), a web-portal for fungal biologists. Our model of interacting with user communities, unique among other sequencing centers, helps organize these communities, improves genome annotation and analysis work, and facilitates new larger-scale genomic projects. This resulted in 20 high-profile papers published in 2011 alone and contributing to the Genomics Encyclopedia of Fungi, which targets fungi related to plant health (symbionts, pathogens, and biocontrol agents) and biorefinery processes (cellulose degradation, sugar fermentation, industrial hosts). Our next grand challenges include larger scale exploration of fungal diversity (1000 fungal genomes), developing molecular tools for DOE-relevant model organisms, and analysis of complex systems and metagenomes.
Mpofu, Leo T.; McLaren, Neal W.
A lack of understanding of host-by-pathogen relations can hinder the success of breeding for resistance to a major disease. Fungal strain pathogenicity has to be understood from the virulence it can cause on susceptible genotypes and host resistance indicates which genotypes have resistance genes. Where the two worlds meet lies the place where researchers match the prevalent pathogen in the area of production with resistant varieties. This paper uses ergosterol concentration analysis as a mea...
Arya, Arun; Perelló, Analía Edith
.... Amidst growing concerns about the environment and food security, the development of management strategies that minimize crop losses and promote sustainable agriculture is increasingly important...
Arya, Arun; Perelló, Analía Edith
... and W.J. Rogers 78 vvi Contents 8 Sustainable Management of Rice Blast (Magnaporthe grisea (Hebert) Barr): 50 Years of Research Progress in Molecular Biology S. Nandy, N. Mandal, P.K. Bhowmik, M...
Janse, Jacqueline J.; Wong, Gary W. K.; Potts, James; Ogorodova, Ludmila M.; Fedorova, Olga S.; Mahesh, P. A.; Sakellariou, Alexandros; Papadopoulos, Nikolaos G.; Knulst, André C.; Versteeg, Serge A.; Kroes, Aloys C. M.; Vossen, Ann C. T. M.; Campos Ponce, Maiza; Kummeling, Ischa; Burney, Peter; van Ree, Ronald; Yazdanbakhsh, Maria
An inverse association between markers of exposure to foodborne and orofecal pathogens and allergic sensitization has been reported. However, the findings of epidemiological studies have not been consistent. This study investigated the relationship between antibodies to hepatitis A, Toxoplasma
Janse, J.J.; Wong, G.W.K.; Potts, J.; Ogorodova, L.M.; Fedorova, O.S.; Mahesh, P.A.; Sakellariou, A.; Papadopoulos, N.G.; Knulst, A.C.; Versteeg, S.A.; Kroes, A.C.M.; Vossen, A.C.T.M.; Campos Ponce, M.; Kummeling, I.; Burney, P.; van Ree, R.; Yazdanbakhsh, M.
Background: An inverse association between markers of exposure to foodborne and orofecal pathogens and allergic sensitization has been reported. However, the findings of epidemiological studies have not been consistent. This study investigated the relationship between antibodies to hepatitis A,
Foodborne illness burdens individuals around the world. Consumption of produce contaminated with bacterial, parasite, and viral pathogens causes a significant proportion of cases of foodborne illness. Farms and packing facilities provide opportunities for contamination. This research aimed to determ...
Wai Ho Lim
Conclusion: Unlike term infants, Gram-negative organism and E coli were the leading pathogen of EOS among VLBW infants. Judicious and timely use of antibiotic therapy is crucial in the care of VLBW infants.
Full Text Available Methicillin-resistant Staphylococcus aureus (MRSA is a major nosocomial pathogen worldwide. Malta is one of the countries with the highest MRSA prevalence in Europe, as identified from hospital blood cultures . However, community prevalence of MRSA has never previously been investigated. This study aimed at establishing the prevalence of community MRSA nasal colonization in Maltese individuals and identifying the clonal characteristics of the detected isolates. Nasal swabs were collected from 329 healthy individuals who were also asked to complete a brief questionnaire about risk factors commonly associated with MRSA carriage and infection. The swabs were transported and enriched in a nutrient broth supplemented with NaCl. The presence of MRSA was then determined by culturing on MRSA Select chromogenic agar and then confirming by several assays, including catalase, coagulase and PBP2a agglutination tests. The isolates were assayed for antibiotic susceptibilities and typed by microarray analysis to determine the clonal characteristics of each strain. The prevalence of MRSA nasal colonization in the healthy Maltese population was found to be 8.81% (95% confidence interval [CI], 5.75–11.87%, much higher than that found in other studies carried out in several countries. No statistical association was found between MRSA carriage and demographics or risk factors; however, this was hindered by the small sample size. Almost all the isolates were fusidic-acid resistant. The majority were found to belong to a local endemic clone (CC5 which seems to be replacing the previously prevalent European clone UK-EMRSA-15 in the country. A new clone (CC50-MRSA-V was also characterized. The presence of such a significant community reservoir of MRSA increases the burdens already faced by the local healthcare system to control the MRSA epidemic. Colonization of MRSA in otherwise healthy individuals may represent a risk for endogenous infection and transmission to
de Mattos, Igor Medici; Soares, Ademilson E E; Tarpy, David R
Honey bee (Apis mellifera L.) populations have been experiencing notable mortality in Europe and North America. No single cause has been identified for these dramatic losses, but rather multiple interacting factors are likely responsible (such as pesticides, malnutrition, habitat loss, and pathogens). Paraquat is one of the most widely used non-selective herbicides, especially in developing countries. This herbicide is considered slightly toxic to honey bees, despite being reported as a highly effective inducer of oxidative stress in a wide range of living systems. Here, we test the effects of paraquat on the expression of detoxification and antioxidant-related genes, as well as on the dynamics of pathogen titers. Moreover, we tested the effects of pollen as mitigating factor to paraquat exposure. Our results show significant changes in the expression of several antioxidant-related and detoxification-related genes in the presence of paraquat, as well as an increase of pathogens titers. Finally, we demonstrate a mitigating effect of pollen through the up-regulation of specific genes and improvement of survival of bees exposed to paraquat. The presence of pollen in the diet was also correlated with a reduced prevalence of Nosema and viral pathogens. We discuss the importance of honey bees' nutrition, especially the availability of pollen, on colony losses chronically reported in the USA and Europe.
Suleiman, T S; Karimuribo, E D; Mdegela, R H
A cross-sectional study was conducted between January and July 2014 in Unguja island of Zanzibar to establish prevalence of subclinical mastitis (SCM) in smallholder dairy cows and patterns of antibacterial susceptibility of major mastitis pathogens isolated. A total of 416 dairy cows from 201 farmers were randomly selected from three districts of Unguja Island to participate in the study. Questionnaire interview, field observation, individual cow examination, California Mastitis Test (CMT) and bacteriological examination were carried out. Kirby-Bauer disc diffusion technique was used to test drug sensitivity for common bacteria isolated. Based on CMT results, the overall prevalence of SCM was 28.6, 48.8 and 64.7% at quarter, cow and farm level, respectively. Prevalence of bacterial infection was recorded at 42.9, 70.9 and 78.6% at quarter, cow and farm examined, respectively. The common bacteria isolated included Staphylococcus aureus (36.8%), Pseudomonas aeruginosa (17.8%), Staphylococcus epidermidis (16.1%), Klebsiella spp. (9.5%), Micrococcus spp. (6.3%) and Escherichia coli (4.9%). In conclusion, findings of this study demonstrated high level of subclinical mastitis at farms, cows and quarters levels with both contagious and environmental bacterial pathogen involved. Therefore, efforts should be directed to the decreased subclinical mastitis by improving sanitary measures and proper milking practice.
Meinhardt, Lyndel W; Costa, Gustavo Gilson Lacerda; Thomazella, Daniela P T; Teixeira, Paulo José P L; Carazzolle, Marcelo Falsarella; Schuster, Stephan C; Carlson, John E; Guiltinan, Mark J; Mieczkowski, Piotr; Farmer, Andrew; Ramaraj, Thiruvarangan; Crozier, Jayne; Davis, Robert E; Shao, Jonathan; Melnick, Rachel L; Pereira, Gonçalo A G; Bailey, Bryan A
The basidiomycete Moniliophthora roreri is the causal agent of Frosty pod rot (FPR) disease of cacao (Theobroma cacao), the source of chocolate, and FPR is one of the most destructive diseases of this important perennial crop in the Americas. This hemibiotroph infects only cacao pods and has an extended biotrophic phase lasting up to sixty days, culminating in plant necrosis and sporulation of the fungus without the formation of a basidiocarp. We sequenced and assembled 52.3 Mb into 3,298 contigs that represent the M. roreri genome. Of the 17,920 predicted open reading frames (OFRs), 13,760 were validated by RNA-Seq. Using read count data from RNA sequencing of cacao pods at 30 and 60 days post infection, differential gene expression was estimated for the biotrophic and necrotrophic phases of this plant-pathogen interaction. The sequencing data were used to develop a genome based secretome for the infected pods. Of the 1,535 genes encoding putative secreted proteins, 1,355 were expressed in the biotrophic and necrotrophic phases. Analysis of the data revealed secretome gene expression that correlated with infection and intercellular growth in the biotrophic phase and invasive growth and plant cellular death in the necrotrophic phase. Genome sequencing and RNA-Seq was used to determine and validate the Moniliophthora roreri genome and secretome. High sequence identity between Moniliophthora roreri genes and Moniliophthora perniciosa genes supports the taxonomic relationship with Moniliophthora perniciosa and the relatedness of this fungus to other basidiomycetes. Analysis of RNA-Seq data from infected plant tissues revealed differentially expressed genes in the biotrophic and necrotrophic phases. The secreted protein genes that were upregulated in the biotrophic phase are primarily associated with breakdown of the intercellular matrix and modification of the fungal mycelia, possibly to mask the fungus from plant defenses. Based on the transcriptome data, the
Tropospheric ozone has been proven to trigger biochemical plant responses that are similar to the ones induced by an attack of fungal pathogens, i.e. it resembles fungal elicitors. This suggests that ozone can represent a valid tool for the study of stress responses and induction of resistance to pathogens. This review ...
Nithya, Angamuthu; Babu, Subramanian
The study aimed at enumerating, identifying and categorizing the endophytic cultivable bacterial community in selected salad vegetables (carrot, cucumber, tomato and onion). Vegetable samples were collected from markets of two vegetable hot spot growing areas, during two different crop harvest seasons. Crude and diluted vegetable extracts were plated and the population of endophytic bacteria was assessed based on morphologically distinguishable colonies. The bacterial isolates were identified by growth in selective media, biochemical tests and 16S rRNA gene sequencing. The endophytic population was found to be comparably higher in cucumber and tomato in both of the sampling locations, whereas lower in carrot and onion. Bacterial isolates belonged to 5 classes covering 46 distinct species belonging to 19 genera. Human opportunistic pathogens were predominant in carrot and onion, whereas plant beneficial bacteria dominated in cucumber and tomato. Out of the 104 isolates, 16.25% are human pathogens and 26.5% are human opportunistic pathogens. Existence of a high population of plant beneficial bacteria was found to have suppressed the population of plant and human pathogens. There is a greater potential to study the native endophytic plant beneficial bacteria for developing them as biocontrol agents against human pathogens that are harboured by plants.
Rivera, Fulton P.; Ochoa, Theresa J.; Ruiz, Joaquim; Medina, Anicia M.; Ecker, Lucie; Mercado, Erik; Gil, Ana I.; Huicho, Luis; Lanata, Claudio F.
Summary Norovirus was detected in 17.4% of 224 diarrhoeal samples from children younger than 24 months of age in Lima, in whom all common pathogens had been excluded (pathogen negative). Norovirus was identified more frequently in children older than 12 months of age than in younger children (34% vs 8%, P<0.001). Among norovirus-positive samples, genogroup II was the predominant group (92%). Compared with rotavirus, norovirus episodes tended to be of shorter duration and less severe. The role of norovirus as a cause of diarrhoea and the ascertainment of its severity in developing countries needs further confirmation by future epidemiological studies. PMID:21962615