WorldWideScience

Sample records for fungal pathogen claviceps

  1. The major Cu,Zn SOD of the phytopathogen Claviceps purpurea is not essential for pathogenicity

    NARCIS (Netherlands)

    Moore, S; De Vries, OMH; Tudzynski, P

    2002-01-01

    Superoxide dismutase (SOD) activities of the biotrophic pathogen Claviceps purpurea, which causes the ergot disease on a wide range of host grasses, were examined in axenic and pathogenic cultures. Almost all SOD activity in axenic culture originated from a single Cu,Zn SOD; a substantial part of th

  2. Fungal pathogens of Proteaceae

    NARCIS (Netherlands)

    Crous, P.W.; Summerell, B.A.; Swart, L.; Denman, S.; Taylor, J.E.; Bezuidenhout, C.M.; Palm, M.E.; Marincowitz, S.; Groenewald, J.Z.

    2011-01-01

    Species of Leucadendron, Leucospermum and Protea (Proteaceae) are in high demand for the international floriculture market due to their brightly coloured and textured flowers or bracts. Fungal pathogens, however, create a serious problem in cultivating flawless blooms. The aim of the present study

  3. Fungal pathogens of Proteaceae

    NARCIS (Netherlands)

    Crous, P.W.; Summerell, B.A.; Swart, L.; Denman, S.; Taylor, J.E.; Bezuidenhout, C.M.; Palm, M.E.; Marincowitz, S.; Groenewald, J.Z.

    2012-01-01

    Species of Leucadendron, Leucospermum and Protea (Proteaceae) are in high demand for the international floriculture market due to their brightly coloured and textured flowers or bracts. Fungal pathogens, however, create a serious problem in cultivating flawless blooms. The aim of the present study

  4. Innate Defense against Fungal Pathogens.

    Science.gov (United States)

    Drummond, Rebecca A; Gaffen, Sarah L; Hise, Amy G; Brown, Gordon D

    2014-11-10

    Human fungal infections have been on the rise in recent years and proved increasingly difficult to treat as a result of the lack of diagnostics, effective antifungal therapies, and vaccines. Most pathogenic fungi do not cause disease unless there is a disturbance in immune homeostasis, which can be caused by modern medical interventions, disease-induced immunosuppression, and naturally occurring human mutations. The innate immune system is well equipped to recognize and destroy pathogenic fungi through specialized cells expressing a broad range of pattern recognition receptors (PRRs). This review will outline the cells and PRRs required for effective antifungal immunity, with a special focus on the major antifungal cytokine IL-17 and recently characterized antifungal inflammasomes.

  5. Divergent and Convergent Evolution of Fungal Pathogenicity.

    Science.gov (United States)

    Shang, Yanfang; Xiao, Guohua; Zheng, Peng; Cen, Kai; Zhan, Shuai; Wang, Chengshu

    2016-05-12

    Fungal pathogens of plants and animals have multifarious effects; they cause devastating damages to agricultures, lead to life-threatening diseases in humans, or induce beneficial effects by reducing insect pest populations. Many virulence factors have been determined in different fungal pathogens; however, the molecular determinants contributing to fungal host selection and adaptation are largely unknown. In this study, we sequenced the genomes of seven ascomycete insect pathogens and performed the genome-wide analyses of 33 species of filamentous ascomycete pathogenic fungi that infect insects (12 species), plants (12), and humans (9). Our results revealed that the genomes of plant pathogens encode more proteins and protein families than the insect and human pathogens. Unexpectedly, more common orthologous protein groups are shared between the insect and plant pathogens than between the two animal group pathogens. We also found that the pathogenicity of host-adapted fungi evolved multiple times, and that both divergent and convergent evolutions occurred during pathogen-host cospeciation thus resulting in protein families with similar features in each fungal group. However, the role of phylogenetic relatedness on the evolution of protein families and therefore pathotype formation could not be ruled out due to the effect of common ancestry. The evolutionary correlation analyses led to the identification of different protein families that correlated with alternate pathotypes. Particularly, the effector-like proteins identified in plant and animal pathogens were strongly linked to fungal host adaptation, suggesting the existence of similar gene-for-gene relationships in fungus-animal interactions that has not been established before. These results well advance our understanding of the evolution of fungal pathogenicity and the factors that contribute to fungal pathotype formation. © The Author 2016. Published by Oxford University Press on behalf of the Society for

  6. Histone Acetylation in Fungal Pathogens of Plants

    Directory of Open Access Journals (Sweden)

    Junhyun Jeon

    2014-03-01

    Full Text Available Acetylation of histone lysine residues occurs in different organisms ranging from yeast to plants and mammals for the regulation of diverse cellular processes. With the identification of enzymes that create or reverse this modification, our understanding on histone acetylation has expanded at an amazing pace during the last two decades. In fungal pathogens of plants, however, the importance of such modification has only just begun to be appreciated in the recent years and there is a dearth of information on how histone acetylation is implicated in fungal pathogenesis. This review covers the current status of research related to histone acetylation in plant pathogenic fungi and considers relevant findings in the interaction between fungal pathogens and host plants. We first describe the families of histone acetyltransferases and deacetylases. Then we provide the cases where histone acetylation was investigated in the context of fungal pathogenesis. Finally, future directions and perspectives in epigenetics of fungal pathogenesis are discussed.

  7. Plant Fungal Pathogens: Methods and Protocols

    NARCIS (Netherlands)

    Bolton, M.D.; Thomma, B.P.H.J.

    2012-01-01

    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 d

  8. The dawn of fungal pathogen genomics.

    Science.gov (United States)

    Xu, Jin-Rong; Peng, You-Liang; Dickman, Martin B; Sharon, Amir

    2006-01-01

    Recent advances in sequencing technologies have led to a remarkable increase in the number of sequenced fungal genomes. Several important plant pathogenic fungi are among those that have been sequenced or are being sequenced. Additional fungal pathogens are likely to be sequenced in the near future. Analysis of the available genomes has provided useful information about genes that may be important for plant infection and colonization. Genome features, such as repetitive sequences, telomeres, conserved syntenic blocks, and expansion of pathogenicity-related genes, are discussed in detail with Magnaporthe oryzae (M. grisea) and Fusarium graminearum as examples. Functional and comparative genomic studies in plant pathogenic fungi, although still in the early stages and limited to a few pathogens, have enormous potential to improve our understanding of the molecular mechanisms involved in host-pathogen interactions. Development of advanced genomics tools and infrastructure is critical for efficient utilization of the vast wealth of available genome sequence information and will form a solid foundation for systems biology studies of plant pathogenic fungi.

  9. Host Pathogen Relations: Exploring Animal Models for Fungal Pathogens

    Directory of Open Access Journals (Sweden)

    Catherine G. Harwood

    2014-06-01

    Full Text Available Pathogenic fungi cause superficial infections but pose a significant public health risk when infections spread to deeper tissues, such as the lung. Within the last three decades, fungi have been identified as the leading cause of nosocomial infections making them the focus of research. This review outlines the model systems such as the mouse, zebrafish larvae, flies, and nematodes, as well as ex vivo and in vitro systems available to study common fungal pathogens.

  10. Host pathogen relations: exploring animal models for fungal pathogens.

    Science.gov (United States)

    Harwood, Catherine G; Rao, Reeta P

    2014-06-30

    Pathogenic fungi cause superficial infections but pose a significant public health risk when infections spread to deeper tissues, such as the lung. Within the last three decades, fungi have been identified as the leading cause of nosocomial infections making them the focus of research. This review outlines the model systems such as the mouse, zebrafish larvae, flies, and nematodes, as well as ex vivo and in vitro systems available to study common fungal pathogens.

  11. Sexual reproduction of human fungal pathogens.

    Science.gov (United States)

    Heitman, Joseph; Carter, Dee A; Dyer, Paul S; Soll, David R

    2014-08-01

    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.

  12. Speciation in fungal and oomycete plant pathogens.

    Science.gov (United States)

    Restrepo, Silvia; Tabima, Javier F; Mideros, Maria F; Grünwald, Niklaus J; Matute, Daniel R

    2014-01-01

    The process of speciation, by definition, involves evolution of one or more reproductive isolating mechanisms that split a single species into two that can no longer interbreed. Determination of which processes are responsible for speciation is important yet challenging. Several studies have proposed that speciation in pathogens is heavily influenced by host-pathogen dynamics and that traits that mediate such interactions (e.g., host mobility, reproductive mode of the pathogen, complexity of the life cycle, and host specificity) must lead to reproductive isolation and ultimately affect speciation rates. In this review, we summarize the main evolutionary processes that lead to speciation of fungal and oomycete plant pathogens and provide an outline of how speciation can be studied rigorously, including novel genetic/genomic developments.

  13. Epigenetic regulation of development and pathogenesis in fungal plant pathogens.

    Science.gov (United States)

    Dubey, Akanksha; Jeon, Junhyun

    2017-08-01

    Evidently, epigenetics is at forefront in explaining the mechanisms underlying the success of human pathogens and in the identification of pathogen-induced modifications within host plants. However, there is a lack of studies highlighting the role of epigenetics in the modulation of the growth and pathogenicity of fungal plant pathogens. In this review, we attempt to highlight and discuss the role of epigenetics in the regulation of the growth and pathogenicity of fungal phytopathogens using Magnaporthe oryzae, a devastating fungal plant pathogen, as a model system. With the perspective of wide application in the understanding of the development, pathogenesis and control of other fungal pathogens, we attempt to provide a synthesized view of the epigenetic studies conducted on M. oryzae to date. First, we discuss the mechanisms of epigenetic modifications in M. oryzae and their impact on fungal development and pathogenicity. Second, we highlight the unexplored epigenetic mechanisms and areas of research that should be considered in the near future to construct a holistic view of epigenetic functioning in M. oryzae and other fungal plant pathogens. Importantly, the development of a complete understanding of the modulation of epigenetic regulation in fungal pathogens can help in the identification of target points to combat fungal pathogenesis. © 2016 BSPP AND JOHN WILEY & SONS LTD.

  14. Fungicide resistance assays for fungal plant pathogens.

    Science.gov (United States)

    Secor, Gary A; Rivera, Viviana V

    2012-01-01

    Fungicide resistance assays are useful to determine if a fungal pathogen has developed resistance to a fungicide used to manage the disease it causes. Laboratory assays are used to determine loss of sensitivity, or resistance, to a fungicide and can explain fungicide failures and for developing successful fungicide recommendations in the field. Laboratory assays for fungicide resistance are conducted by measuring reductions in growth or spore germination of fungi in the presence of fungicide, or by molecular procedures. This chapter describes two techniques for measuring fungicide resistance, using the sugarbeet leaf spot fungus Cercospora beticola as a model for the protocol. Two procedures are described for fungicides from two different classes; growth reduction for triazole (sterol demethylation inhibitor; DMI) fungicides, and inhibition of spore germination for quinone outside inhibitor (QoI) fungicides.

  15. Evolution and genome architecture in fungal plant pathogens.

    Science.gov (United States)

    Möller, Mareike; Stukenbrock, Eva H

    2017-08-07

    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.

  16. The Top 10 fungal pathogens in molecular plant pathology

    NARCIS (Netherlands)

    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.

    2012-01-01

    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 co

  17. The Top 10 fungal pathogens in molecular plant pathology

    NARCIS (Netherlands)

    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.

    2012-01-01

    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

  18. The Top 10 fungal pathogens in molecular plant pathology

    NARCIS (Netherlands)

    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.

    2012-01-01

    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 co

  19. Etiological Analysis of Fungal Keratitis and Rapid Identification of Predominant Fungal Pathogens.

    Science.gov (United States)

    He, Dan; Hao, Jilong; Gao, Song; Wan, Xue; Wang, Wanting; Shan, Qiushi; Wang, Li

    2016-02-01

    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.

  20. Comparative Genomic Analysis of Human Fungal Pathogens Causing Paracoccidioidomycosis

    OpenAIRE

    Desjardins, Christopher A; Champion, Mia D.; Holder, Jason W.; Muszewska, Anna; Goldberg, Jonathan; Bailao, Alexandre M.; Brigido, Marcelo de Macedo; Silva Ferreira, Marcia Eliana da; Garcia, Ana Maria; Grynberg, Marcin; Gujja, Sharvari; Heiman, David I.; Henn, Matthew R.; Kodira, Chinnappa D.; Leon-Narvaez, Henry

    2011-01-01

    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 brasi...

  1. Molecular Identification of Human Fungal Pathogens

    Science.gov (United States)

    2011-03-01

    no pigment seen on the hyphal walls on hematoxylin-eosin or melan A staining. The biopsy specimen was sent for bacterial and fungal cul- tures, but the...aim was to design universal primers and then develop a PCR mix, which would be able to reliably amplify template from any specimen, even pigmented ...which if accepted, will result in thirty journal publications. There was also one book chapter published. II. Seventeen abstracts have been

  2. Splash : the dispersal of fungal plant pathogens in rain events

    NARCIS (Netherlands)

    Pielaat, A.

    2000-01-01

    Models were developed to study splash dispersal of fungal plant pathogens in space and time. The models incorporate the main mechanisms involved in splash dispersal, that is 1. A raindrop hits the thin water film on the crop surface containing spores and spores are dispersed in the splashing rain dr

  3. Quantitative molecular diagnostic assays of grain washes for Claviceps purpurea are correlated with visual determinations of ergot contamination

    Science.gov (United States)

    Comte, Alexia; Gräfenhan, Tom; Links, Matthew G.; Hemmingsen, Sean M.

    2017-01-01

    We examined the epiphytic microbiome of cereal grain using the universal barcode chaperonin-60 (cpn60). Microbial community profiling of seed washes containing DNA extracts prepared from field-grown cereal grain detected sequences from a fungus identified only to Class Sordariomycetes. To identify the fungal sequence and to improve the reference database, we determined cpn60 sequences from field-collected and reference strains of the ergot fungus, Claviceps purpurea. These data allowed us to identify this fungal sequence as deriving from C. purpurea, and suggested that C. purpurea DNA is readily detectable on agricultural commodities, including those for which ergot was not identified as a grading factor. To get a sense of the prevalence and level of C. purpurea DNA in cereal grains, we developed a quantitative PCR assay based on the fungal internal transcribed spacer (ITS) and applied it to 137 samples from the 2014 crop year. The amount of Claviceps DNA quantified correlated strongly with the proportion of ergot sclerotia identified in each grain lot, although there was evidence that non-target organisms were responsible for some false positives with the ITS-based assay. We therefore developed a cpn60-targeted loop-mediated isothermal amplification assay and applied it to the same grain wash samples. The time to positive displayed a significant, inverse correlation to ergot levels determined by visual ratings. These results indicate that both laboratory-based and field-adaptable molecular diagnostic assays can be used to detect and quantify pathogen load in bulk commodities using cereal grain washes. PMID:28257512

  4. Quantitative molecular diagnostic assays of grain washes for Claviceps purpurea are correlated with visual determinations of ergot contamination.

    Science.gov (United States)

    Comte, Alexia; Gräfenhan, Tom; Links, Matthew G; Hemmingsen, Sean M; Dumonceaux, Tim J

    2017-01-01

    We examined the epiphytic microbiome of cereal grain using the universal barcode chaperonin-60 (cpn60). Microbial community profiling of seed washes containing DNA extracts prepared from field-grown cereal grain detected sequences from a fungus identified only to Class Sordariomycetes. To identify the fungal sequence and to improve the reference database, we determined cpn60 sequences from field-collected and reference strains of the ergot fungus, Claviceps purpurea. These data allowed us to identify this fungal sequence as deriving from C. purpurea, and suggested that C. purpurea DNA is readily detectable on agricultural commodities, including those for which ergot was not identified as a grading factor. To get a sense of the prevalence and level of C. purpurea DNA in cereal grains, we developed a quantitative PCR assay based on the fungal internal transcribed spacer (ITS) and applied it to 137 samples from the 2014 crop year. The amount of Claviceps DNA quantified correlated strongly with the proportion of ergot sclerotia identified in each grain lot, although there was evidence that non-target organisms were responsible for some false positives with the ITS-based assay. We therefore developed a cpn60-targeted loop-mediated isothermal amplification assay and applied it to the same grain wash samples. The time to positive displayed a significant, inverse correlation to ergot levels determined by visual ratings. These results indicate that both laboratory-based and field-adaptable molecular diagnostic assays can be used to detect and quantify pathogen load in bulk commodities using cereal grain washes.

  5. Novel disease susceptibility factors for fungal necrotrophic pathogens in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Albor Dobón

    2015-04-01

    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.

  6. Effects of Ionizing Radiation on Postharvest Fungal Pathogens

    Directory of Open Access Journals (Sweden)

    Rae-Dong Jeong

    2015-06-01

    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.

  7. Translocation of cell-penetrating peptides into Candida fungal pathogens.

    Science.gov (United States)

    Gong, Zifan; Karlsson, Amy J

    2017-09-01

    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.

  8. Granule-Dependent Natural Killer Cell Cytotoxicity to Fungal Pathogens

    Science.gov (United States)

    Ogbomo, Henry; Mody, Christopher H.

    2017-01-01

    Natural killer (NK) cells kill or inhibit the growth of a number of fungi including Cryptococcus, Candida, Aspergillus, Rhizopus, and Paracoccidioides. Although many fungi are not dangerous, invasive fungal pathogens, such as Cryptococcus neoformans, cause life-threatening disease in individuals with impaired cell-mediated immunity. While there are similarities to cell-mediated killing of tumor cells, there are also important differences. Similar to tumor killing, NK cells directly kill fungi in a receptor-mediated and cytotoxic granule-dependent manner. Unlike tumor cell killing where multiple NK cell-activating receptors cooperate and signal events that mediate cytotoxicity, only the NKp30 receptor has been described to mediate signaling events that trigger the NK cell to mobilize its cytolytic payload to the site of interaction with C. neoformans and Candida albicans, subsequently leading to granule exocytosis and fungal killing. More recently, the NKp46 receptor was reported to bind Candida glabrata adhesins Epa1, 6, and 7 and directly mediate fungal clearance. A number of unanswered questions remain. For example, is only one NK cell-activating receptor sufficient for signaling leading to fungal killing? Are the signaling pathways activated by fungi similar to those activated by tumor cells during NK cell killing? How do the cytolytic granules traffic to the site of interaction with fungi, and how does this process compare with tumor killing? Recent insights into receptor use, intracellular signaling and cytolytic granule trafficking during NK cell-mediated fungal killing will be compared to tumor killing, and the implications for therapeutic approaches will be discussed. PMID:28123389

  9. Comparative Genomic Analysis of Human Fungal Pathogens Causing Paracoccidioidomycosis

    Science.gov (United States)

    Desjardins, Christopher A.; Champion, Mia D.; Holder, Jason W.; Muszewska, Anna; Goldberg, Jonathan; Bailão, Alexandre M.; Brigido, Marcelo Macedo; Ferreira, Márcia Eliana da Silva; Garcia, Ana Maria; Grynberg, Marcin; Gujja, Sharvari; Heiman, David I.; Henn, Matthew R.; Kodira, Chinnappa D.; León-Narváez, Henry; Longo, Larissa V. G.; Ma, Li-Jun; Malavazi, Iran; Matsuo, Alisson L.; Morais, Flavia V.; Pereira, Maristela; Rodríguez-Brito, Sabrina; Sakthikumar, Sharadha; Salem-Izacc, Silvia M.; Sykes, Sean M.; Teixeira, Marcus Melo; Vallejo, Milene C.; Walter, Maria Emília Machado Telles; Yandava, Chandri; Young, Sarah; Zeng, Qiandong; Zucker, Jeremy; Felipe, Maria Sueli; Goldman, Gustavo H.; Haas, Brian J.; McEwen, Juan G.; Nino-Vega, Gustavo; Puccia, Rosana; San-Blas, Gioconda; Soares, Celia Maria de Almeida; Birren, Bruce W.; Cuomo, Christina A.

    2011-01-01

    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 species of

  10. Comparative genomic analysis of human fungal pathogens causing paracoccidioidomycosis.

    Directory of Open Access Journals (Sweden)

    Christopher A Desjardins

    2011-10-01

    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

  11. Oxidative Stress Responses in the Human Fungal Pathogen, Candida albicans

    Directory of Open Access Journals (Sweden)

    Alessandra da Silva Dantas

    2015-02-01

    Full Text Available 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.

  12. Application of a Non-amplification based Technology to Detect Invasive Fungal Pathogens

    Science.gov (United States)

    Hsu, Joe L.; Binkley, Jon; Clemons, Karl V.; Stevens, David A.; Nicolls, Mark R.; Holodniy, Mark

    2014-01-01

    Current diagnostic techniques for fungal diseases could be improved with respect to sensitivity, specificity and timeliness. To address this clinical need, we adapted a non-amplification based nucleic acid detection technology to identify fungal pathogens. We demonstrate a high-specificity, detection sensitivity, reproducibility and multiplex capacity for detecting fungal strains. PMID:24359934

  13. Application of a Non-amplification based Technology to Detect Invasive Fungal Pathogens

    OpenAIRE

    Hsu, Joe L.; Binkley, Jon; Clemons, Karl V.; Stevens, David A.; Nicolls, Mark R.; Holodniy, Mark

    2013-01-01

    Current diagnostic techniques for fungal diseases could be improved with respect to sensitivity, specificity and timeliness. To address this clinical need, we adapted a non-amplification based nucleic acid detection technology to identify fungal pathogens. We demonstrate a high-specificity, detection sensitivity, reproducibility and multiplex capacity for detecting fungal strains.

  14. Pathogenicity of fungal species in aroid ( Colocasia and Xanthosoma rhizomes

    Directory of Open Access Journals (Sweden)

    Amaurys Dávila Martínez

    2016-07-01

    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.

  15. Development of a Multiplex PCR Method to Detect Fungal Pathogens for Quarantine on Exported Cacti

    OpenAIRE

    Hyun ji Cho; Seong Won Hong; Hyun-ju Kim; Youn-Sig Kwak

    2016-01-01

    Major diseases in grafted cacti have been reported and Fusarium oxysporum, Bipolaris cactivora, Phytophthora spp. and Collectotrichum spp. are known as causal pathogens. These pathogens can lead to plant death after infection. Therefore, some European countries have quarantined imported cacti that are infected with specific fungal pathogens. Consequently, we developed PCR detection methods to identify four quarantined fungal pathogens and reduce export rejection rates of Korean grafted cacti....

  16. Functional genomics in the rice blast fungus to unravel the fungal pathogenicity

    Institute of Scientific and Technical Information of China (English)

    Junhyun JEON; Jaehyuk CHOI; Jongsun PARK; Yong-Hwan LEE

    2008-01-01

    A rapidly growing number of successful genome sequencing projects in plant pathogenic fungi greatly increase the demands for tools and methodologies to study fungal pathogenicity at genomic scale. Magnaporthe oryzae is an economically important plant pathogenic fungus whose genome is fully sequenced. Recently we have reported the development and application of functional genomics platform technologies in M. oryzae. This model approach would have many practical ramifications in design and implementation of upcoming functional genomics studies of filamentous fungi aimed at understanding fungal pathogenicity.

  17. Essential metals at the host-pathogen interface: nutritional immunity and micronutrient assimilation by human fungal pathogens.

    Science.gov (United States)

    Crawford, Aaron; Wilson, Duncan

    2015-11-01

    The ability of pathogenic microorganisms to assimilate sufficient nutrients for growth within their hosts is a fundamental requirement for pathogenicity. However, certain trace nutrients, including iron, zinc and manganese, are actively withheld from invading pathogens in a process called nutritional immunity. Therefore, successful pathogenic species must have evolved specialized mechanisms in order to adapt to the nutritionally restrictive environment of the host and cause disease. In this review, we discuss recent advances which have been made in our understanding of fungal iron and zinc acquisition strategies and nutritional immunity against fungal infections, and explore the mechanisms of micronutrient uptake by human pathogenic fungi.

  18. Emerging fungal pathogen Ophidiomyces ophiodiicola in wild European snakes

    Science.gov (United States)

    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

    2017-01-01

    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.

  19. Global distribution of two fungal pathogens threatening endangered sea turtles.

    Science.gov (United States)

    Sarmiento-Ramírez, Jullie M; Abella-Pérez, Elena; Phillott, Andrea D; Sim, Jolene; van West, Pieter; Martín, María P; Marco, Adolfo; Diéguez-Uribeondo, Javier

    2014-01-01

    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.

  20. Global distribution of two fungal pathogens threatening endangered sea turtles.

    Directory of Open Access Journals (Sweden)

    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.

  1. Morphological and molecular characterization of fungal pathogen, Magnaphorthe oryzae

    Energy Technology Data Exchange (ETDEWEB)

    Hasan, Nor’Aishah, E-mail: aishahnh@ns.uitm.edu.my [Faculty of Applied Science, UniversitiTeknologi MARA (UiTM), Kuala Pilah, Negeri Sembilan (Malaysia); Rafii, Mohd Y., E-mail: mrafii@upm.edu.my [Institute of Tropical Agriculture, Universiti Putra Malaysia (UPM), Serdang, Selangor (Malaysia); Department of Crop Science, Universiti Putra Malaysia (UPM), Serdang, Selangor (Malaysia); Rahim, Harun A. [Agrotechnology & Bioscience Division, Malaysian Nuclear Agency, Bangi, Kajang, Selangor (Malaysia); Ali, Nusaibah Syd [Department of Plant Protection, Universiti Putra Malaysia (UPM), Serdang, Selangor (Malaysia); Mazlan, Norida [Department of Agriculture Technology, Universiti Putra Malaysia (UPM), Serdang, Selangor (Malaysia); Abdullah, Shamsiah [Faculty of Plantation and Agrotechnology, UniversitiTeknologi MARA (UiTM), Shah Alam, Selangor (Malaysia)

    2016-02-01

    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.

  2. Leaf Litter Inhibits Growth of an Amphibian Fungal Pathogen.

    Science.gov (United States)

    Stoler, Aaron B; Berven, Keith A; Raffel, Thomas R

    2016-06-01

    Past studies have found a heterogeneous distribution of the amphibian chytrid fungal pathogen, Batrachochytrium dendrobatidis (Bd). Recent studies have accounted for some of this heterogeneity through a positive association between canopy cover and Bd abundance, which is attributed to the cooling effect of canopy cover. We questioned whether leaf litter inputs that are also associated with canopy cover might also alter Bd growth. Leaf litter inputs exhibit tremendous interspecific chemical variation, and we hypothesized that Bd growth varies with leachate chemistry. We also hypothesized that Bd uses leaf litter as a growth substrate. To test these hypotheses, we conducted laboratory trials in which we exposed cultures of Bd to leachate of 12 temperate leaf litter species at varying dilutions. Using a subset of those 12 litter species, we also exposed Bd to pre-leached litter substrate. We found that exposure to litter leachate and substrate reduced Bd spore and sporangia densities, although there was substantial variation among treatments. In particular, Bd densities were inversely correlated with concentrations of phenolic acids. We conducted a field survey of phenolic concentrations in natural wetlands which verified that the leachate concentrations in our lab study are ecologically relevant. Our study reinforces prior indications that positive associations between canopy cover and Bd abundance are likely mediated by water temperature effects, but this phenomenon might be counteracted by changes in aquatic chemistry from leaf litter inputs.

  3. Functional analysis of LysM effectors secreted by fungal plant pathogens

    NARCIS (Netherlands)

    Kombrink, A.

    2014-01-01

      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

  4. The use of plants to protect plants and food against fungal pathogens

    African Journals Online (AJOL)

    The use of plants to protect plants and food against fungal pathogens: a review. ... associated with these chemicals have motivated researchers and cultivators to ... may be lower if the different compounds affect a different metabolic process.

  5. Sensitivity of the brown dog tick, Rhipicephalus sanguineus to fungal pathogens

    Science.gov (United States)

    The brown dog tick, Rhipicephalus sanguineus, remains a primary ectoparasite concern in many dog kennels, shelters and residential homes. Challenges such as effective pesticide delivery and pesticide resistance confound control efforts. Use of biological control approaches such as fungal pathogen...

  6. Cloning, characterization, and targeted disruption of cpcat1, coding for an in planta secreted catalase of Claviceps purpurea.

    Science.gov (United States)

    Garre, V; Müller, U; Tudzynski, P

    1998-08-01

    Claviceps purpurea has been shown to secrete catalases in axenic and parasitic culture. In order to determine the importance of these enzymes in the host-parasite interaction, especially their role in overcoming oxidative stress imposed on the pathogen by the plant's defense system, the catR gene from A. niger was used to isolate a putative catalase gene from a genomic library of C. purpurea, cpcat1 consists of an open reading frame of 2,148 bp that is interrupted by five introns. Its derived gene product shows significant homology to fungal catalases and contains a putative signal peptide of 19 amino acids and three putative N-glycosylation sites, which indicates that CPCAT1 is a secreted catalase. Disruption of the gene by a gene replacement approach resulted in the loss of two catalase isoforms, CATC and CATD, strongly suggesting that they are both encoded by cpcat1. CATD is the major secreted catalase of C. purpurea and is furthermore the only catalase present in the honeydew of infected rye ears. Deletion mutants of cpcat1 were inoculated on rye plants and showed no significant reduction in virulence. Ovarian tissue and honeydew of plants inoculated with the mutants lacked CATD, confirming that this catalase is not essential for colonization of the host tissue by C. purpurea.

  7. THE USE OF PLANTS TO PROTECT PLANTS AND FOOD AGAINST FUNGAL PATHOGENS: A REVIEW.

    Science.gov (United States)

    Shuping, D S S; Eloff, J N

    2017-01-01

    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

  8. LysM receptor-like kinases to improve plant defense response against fungal pathogens

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Jinrong; Stacey, Gary; Stacey, Minviluz; Zhang, Xuecheng

    2013-10-15

    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.

  9. LysM receptor-like kinases to improve plant defense response against fungal pathogens

    Science.gov (United States)

    Wan, Jinrong [Columbia, MO; Stacey, Gary [Columbia, MO; Stacey, Minviluz [Columbia, MO; Zhang, Xuecheng [Columbia, MO

    2012-01-17

    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.

  10. Antifungal activity of different natural dyes against traditional products affected fungal pathogens

    Institute of Scientific and Technical Information of China (English)

    R Mari selvam; AJA Ranjit Singh; K Kalirajan

    2012-01-01

    Objective: In the present study to evaluate the anti fungal activity of natural dyes against traditional products affected fungal pathogens. Methods: Many traditional craft products affected fungal pathogens were isolated using potato dextrose agar medium. The isolated fungus were identified by morphological and microscopically characterization using Alexopolus manual. 50μl of Turmeric, Terminalli, Guava and Henna natural dyes were poured into the wells of the culture plates. If antifungal activity was present on the plates, it was indicated by an inhibition zone surrounding the well containing the natural dye. Result: At a dose level of 50μl of terminalli dye was able to inhibit the growth of all the fungi tested. The absorbance rate of natural dyes analyzed by UV Spectrophotometer. The absorbance rate is high in terminalli (2.266) and turmeric (2.255). Conclusions: Natural dyes were bound with traditional products to give good colour and good antimicrobial activity against isolated fungal pathogens.

  11. Repression of fungal plant pathogens and fungal-related contaminants: Selected ecosystem services by soil fauna communities in agroecosystems

    Science.gov (United States)

    Meyer-Wolfarth, Friederike; Schrader, Stefan; Oldenburg, Elisabeth; Brunotte, Joachim; Weinert, Joachim

    2017-04-01

    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

  12. Identification of diverse mycoviruses through metatranscriptomics characterization of the viromes of five major fungal plant pathogens

    Science.gov (United States)

    Infection of plant pathogenic fungi by mycoviruses can attenuate their virulence on plants and vigor in culture. In this study, we described the viromes of 275 isolates of five widely dispersed plant pathogenic fungal species (Colletotrichum truncatum, Macrophomina phaseolina, Phomopsis longicolla, ...

  13. Current ecological understanding of fungal-like pathogens of fish: what lies beneath?

    Directory of Open Access Journals (Sweden)

    Rodolphe Elie Gozlan

    2014-02-01

    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.

  14. Current ecological understanding of fungal-like pathogens of fish: what lies beneath?

    Science.gov (United States)

    Gozlan, Rodolphe E; Marshall, Wyth L; Lilje, Osu; Jessop, Casey N; Gleason, Frank H; Andreou, Demetra

    2014-01-01

    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.

  15. Efficacy of Antibody to PNAG Against Keratitis Caused by Fungal Pathogens

    Science.gov (United States)

    Zhao, Ge; Zaidi, Tanweer S.; Bozkurt-Guzel, Cagla; Zaidi, Tauqeer H.; Lederer, James A.; Priebe, Gregory P.; Pier, Gerald B.

    2016-01-01

    Purpose Developing immunotherapies for fungal eye infections is a high priority. We analyzed fungal pathogens for expression of the surface polysaccharide, poly-N-acetyl glucosamine (PNAG), and used a mouse model of ocular keratitis caused by Aspergillus flavus, A. fumigatus, or Fusarium solani to determine if PNAG was an immunotherapy target and requirements for ancillary cellular and molecular immune effectors. Methods Enzyme-linked immunosorbent assay (ELISA) or immunofluorescence was used to detect PNAG on fungal cells. Keratitis was induced by scratching corneas of C57BL/6, IL-17R KO, RAG-1 KO, or IL-22 KO mice followed by inoculation with fungal pathogens. Goat antibodies to PNAG, a PNAG-specific human IgG1 monoclonal antibody, or control antibodies were injected either prophylactically plus therapeutically or therapeutically only, and corneal pathology and fungal levels determined in infected eyes at 24 or 48 hours after infection. Results All tested fungal species produced PNAG. Prophylactic or therapeutic treatment by intraperitoneal (IP) injection of antibody to PNAG combined with post-infection topical application of antibody, the latter also used for A. fumigatus, led to reduced fungal levels, corneal pathology, and cytokine expression. Topical administration only of the PNAG monoclonal antibodies (MAb) reduced fungal loads and corneal pathology. There was no antibody protection in IL-17R KO, RAG-1 KO, or IL-22 KO mice. Conclusions Poly-N-acetyl glucosamine is produced by clinically important fungal ocular pathogens. Antibody to PNAG demonstrated protection against Aspergillus and Fusarium keratitis, requiring T cells producing IL-17 and IL-22. These findings indicate the potential to prevent or treat fungal infections by vaccines and immunotherapeutics to PNAG. PMID:28002842

  16. Epidemiology and identification of potential fungal pathogens causing invasive fungal infections in a tertiary care hospital in northeast Thailand.

    Science.gov (United States)

    Faksri, Kiatichai; Kaewkes, Wanlop; Chaicumpar, Kunyaluk; Chaimanee, Prajuab; Wongwajana, Suwin

    2014-11-01

    Invasive fungal infections (IFIs) are life threatening and associated with a high mortality rate. Here, we describe the distribution of pathogens, host risk factors, and significance of fungi isolated from patients with IFIs. The study included 861 fungal isolates recovered between 2006 and 2011 from 802 patients at Srinagarind Hospital, Thailand. Based on the European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infectious Diseases Mycoses Study Group 2008 criteria, 28.5% (245/861 isolates) of the fungal isolates were considered to be causative agents of IFIs. The most common fungus was Candida albicans (46%, 396/861 isolates). However, the most common yeast causing IFIs was Cryptococcus neoformans (34.7%, 85/245 isolates), while the most common mould was Penicillium marneffei (10.6%, 26/245 isolates). Cryptococcosis was significantly associated with human immunodeficiency virus infections (P 95%), moderate (5%-95%), and rare (<5%) pathogens. This classification system could facilitate the prediction of the likelihood of diseases caused by the isolated fungi.

  17. Fungal keratitis due to Schizophyllum commune: an emerging pathogenic fungus.

    Science.gov (United States)

    Reddy, Ashok Kumar; Ashok, Rangaiahgari; Majety, Madhavi; Chitta, Megharaj; Narayen, Nitesh

    2016-07-12

    Fungal keratitis due to Schizophyllum commune is very rare. In this study, we report the clinical and microbiological profile of five patients with fungal keratitis due to S. commune. Direct microscopic examination of corneal scrapings from all five patients showed septate branching hyaline fungal filaments. Similarly, in all five patients Sabouraud dextrose agar (SDA) plates inoculated with corneal scrapings showed white, cottony colonies on the second day of incubation. Lactophenol cotton blue stained wet preparation of 7-day-old colonies on SDA revealed clamp connections and no spores. The fungus was identified by its characteristic clamp connections, fan-shaped bracket fruiting body with pinkish-grey longitudinally split-radiating gills. The phenotypic identification of one of the five isolates further conformed by ITS sequencing. Treatment outcome was available for two of the five patients; in these two patients, the keratitis resolved with topical natamycin. © 2016 Blackwell Verlag GmbH.

  18. Anti-biotic Effect of Slightly Acidic Electrolyzed Water on Plant Bacterial / Fungal Pathogen

    OpenAIRE

    津野, 和宣; 中村, 悌一

    2012-01-01

    The anti-biotic effect of slightly acidic electrolyzed water on plant pathogen was determined. The spores of 4 kinds of fungal pathogen and 17 kinds of plant pathogenic bacteria were applied at different concentration.###Slightly acidic electrolyzed water showed strong growth inhibition in germination of fungi spores tested. In addition, by the treatment with slightly acidic electrolyzed water for 30 sec., all kinds of bacteria tested were inhibited to grow on the medium.###The anti-biotic ef...

  19. Bat white-nose syndrome: An emerging fungal pathogen?

    Science.gov (United States)

    Blehert, D.S.; Hicks, A.C.; Behr, M.; Meteyer, C.U.; Berlowski-Zier, B. M.; Buckles, E.L.; Coleman, J.T.H.; Darling, S.R.; Gargas, A.; Niver, R.; Okoniewski, J.C.; Rudd, R.J.; Stone, W.B.

    2009-01-01

    White-nose syndrome (WNS) is a condition associated with an unprecedented bat mortality event in the northeastern United States. Since the winter of 2006*2007, bat declines exceeding 75% have been observed at surveyed hibernacula. Affected bats often present with visually striking white fungal growth on their muzzles, ears, and/or wing membranes. Direct microscopy and culture analyses demonstrated that the skin of WNS-affected bats is colonized by a psychro-philic fungus that is phylogenetically related to Geomyces spp. but with a conidial morphology distinct from characterized members of this genus. This report characterizes the cutaneous fungal infection associated with WNS.

  20. Bat white-nose syndrome: an emerging fungal pathogen?

    Science.gov (United States)

    Blehert, David S; Hicks, Alan C; Behr, Melissa; Meteyer, Carol U; Berlowski-Zier, Brenda M; Buckles, Elizabeth L; Coleman, Jeremy T H; Darling, Scott R; Gargas, Andrea; Niver, Robyn; Okoniewski, Joseph C; Rudd, Robert J; Stone, Ward B

    2009-01-09

    White-nose syndrome (WNS) is a condition associated with an unprecedented bat mortality event in the northeastern United States. Since the winter of 2006*2007, bat declines exceeding 75% have been observed at surveyed hibernacula. Affected bats often present with visually striking white fungal growth on their muzzles, ears, and/or wing membranes. Direct microscopy and culture analyses demonstrated that the skin of WNS-affected bats is colonized by a psychrophilic fungus that is phylogenetically related to Geomyces spp. but with a conidial morphology distinct from characterized members of this genus. This report characterizes the cutaneous fungal infection associated with WNS.

  1. Novel insights into host-fungal pathogen interactions derived from live-cell imaging.

    Science.gov (United States)

    Bain, Judith; Gow, Neil A R; Erwig, Lars-Peter

    2015-03-01

    The theoretical physicist and Nobel laureate Richard Feynman outlined in his 1959 lecture, "There's plenty of room at the bottom", the enormous possibility of producing and visualising things at smaller scales. The advent of advanced scanning and transmission electron microscopy and high-resolution microscopy has begun to open the door to visualise host-pathogen interactions at smaller scales, and spinning disc confocal and two-photon microscopy has improved our ability to study these events in real time in three dimensions. The aim of this review is to illustrate some of the advances in understanding host-fungal interactions that have been made in recent years in particular those relating to the interactions of live fungal pathogens with phagocytes. Dynamic imaging of host-pathogen interactions has recently revealed novel detail and unsuspected mechanistic insights, facilitating the dissection of the phagocytic process into its component parts. Here, we will highlight advances in our knowledge of host-fungal pathogen interactions, including the specific effects of fungal cell viability, cell wall composition and morphogenesis on the phagocytic process and try to define the relative contributions of neutrophils and macrophages to the clearance of fungal pathogens in vitro and the infected host.

  2. Development of a Selective Medium for the Fungal Pathogen Fusarium graminearum Using Toxoflavin Produced by the Bacterial Pathogen Burkholderia glumae

    Directory of Open Access Journals (Sweden)

    Boknam Jung

    2013-12-01

    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.

  3. Development of a Multiplex PCR Method to Detect Fungal Pathogens for Quarantine on Exported Cacti

    Science.gov (United States)

    Cho, Hyun ji; Hong, Seong Won; Kim, Hyun-ju; Kwak, Youn-Sig

    2016-01-01

    Major diseases in grafted cacti have been reported and Fusarium oxysporum, Bipolaris cactivora, Phytophthora spp. and Collectotrichum spp. are known as causal pathogens. These pathogens can lead to plant death after infection. Therefore, some European countries have quarantined imported cacti that are infected with specific fungal pathogens. Consequently, we developed PCR detection methods to identify four quarantined fungal pathogens and reduce export rejection rates of Korean grafted cacti. The pathogen specific primer sets F.oF-F.oR, B.CF-B.CR, P.nF-P.nR, and P.cF-P.CR were tested for F. oxysporum, B. cactivora, P. nicotinae, and P. cactorum, respectively. The F.oF-F.oR primer set was designed from the Fusarium ITS region; the B.CF-B.CR and P.nF-P.nR primers respectively from Bipolaris and Phytophthora ITS1; and the P.cF-P.CR primer set from the Ypt1protein gene region. The quarantine fungal pathogen primer pairs were amplified to the specific number of base pairs in each of the following fungal pathogens: 210-bp (F. oxysporum), 510-bp (B. cactivora), 313-bp (P. nicotinae), and 447-bp (P. cactorum). The detection limit for the mono- and multiplex PCR primer sets was 0.1 ng of template DNA under in vitro conditions. Therefore, each primer set successfully diagnosed contamination of quarantine pathogens in export grafted cacti. Consequently, our methodology is a viable tool to screen contamination of the fungal pathogen in exported grafted cacti. PMID:26889115

  4. Development of a Multiplex PCR Method to Detect Fungal Pathogens for Quarantine on Exported Cacti

    Directory of Open Access Journals (Sweden)

    Hyun ji Cho

    2016-02-01

    Full Text Available Major diseases in grafted cacti have been reported and Fusarium oxysporum, Bipolaris cactivora, Phytophthora spp. and Collectotrichum spp. are known as causal pathogens. These pathogens can lead to plant death after infection. Therefore, some European countries have quarantined imported cacti that are infected with specific fungal pathogens. Consequently, we developed PCR detection methods to identify four quarantined fungal pathogens and reduce export rejection rates of Korean grafted cacti. The pathogen specific primer sets F.oF-F.oR, B.CF-B.CR, P.nF-P.nR, and P.cF-P.CR were tested for F. oxysporum, B. cactivora, P. nicotinae, and P. cactorum, respectively. The F.oF-F.oR primer set was designed from the Fusarium ITS region; the B.CF-B.CR and P.nF-P.nR primers respectively from Bipolaris and Phytophthora ITS1; and the P.cF-P.CR primer set from the Ypt1protein gene region. The quarantine fungal pathogen primer pairs were amplified to the specific number of base pairs in each of the following fungal pathogens: 210-bp (F. oxysporum, 510-bp (B. cactivora, 313-bp (P. nicotinae, and 447-bp (P. cactorum. The detection limit for the mono- and multiplex PCR primer sets was 0.1 ng of template DNA under in vitro conditions. Therefore, each primer set successfully diagnosed contamination of quarantine pathogens in export grafted cacti. Consequently, our methodology is a viable tool to screen contamination of the fungal pathogen in exported grafted cacti.

  5. Development of a Multiplex PCR Method to Detect Fungal Pathogens for Quarantine on Exported Cacti.

    Science.gov (United States)

    Cho, Hyun Ji; Hong, Seong Won; Kim, Hyun-Ju; Kwak, Youn-Sig

    2016-02-01

    Major diseases in grafted cacti have been reported and Fusarium oxysporum, Bipolaris cactivora, Phytophthora spp. and Collectotrichum spp. are known as causal pathogens. These pathogens can lead to plant death after infection. Therefore, some European countries have quarantined imported cacti that are infected with specific fungal pathogens. Consequently, we developed PCR detection methods to identify four quarantined fungal pathogens and reduce export rejection rates of Korean grafted cacti. The pathogen specific primer sets F.oF-F.oR, B.CF-B.CR, P.nF-P.nR, and P.cF-P.CR were tested for F. oxysporum, B. cactivora, P. nicotinae, and P. cactorum, respectively. The F.oF-F.oR primer set was designed from the Fusarium ITS region; the B.CF-B.CR and P.nF-P.nR primers respectively from Bipolaris and Phytophthora ITS1; and the P.cF-P.CR primer set from the Ypt1protein gene region. The quarantine fungal pathogen primer pairs were amplified to the specific number of base pairs in each of the following fungal pathogens: 210-bp (F. oxysporum), 510-bp (B. cactivora), 313-bp (P. nicotinae), and 447-bp (P. cactorum). The detection limit for the mono- and multiplex PCR primer sets was 0.1 ng of template DNA under in vitro conditions. Therefore, each primer set successfully diagnosed contamination of quarantine pathogens in export grafted cacti. Consequently, our methodology is a viable tool to screen contamination of the fungal pathogen in exported grafted cacti.

  6. EFFICACY OF LEAF EXTRACTS AGAINST THE POST HARVEST FUNGAL PATHOGENS OF COWPEA

    Directory of Open Access Journals (Sweden)

    Umesh P. Mogle

    2013-01-01

    Full Text Available The study aimed to control the fungi associated with cowpea legumes. Post-harvest fungal diseases of cowpea legumes in the markets of Jalna (MS India, were isolated, identified and maintained on an agar medium. Efficacy of 10 % aqueous leaf extracts was tested against the growth of 06 post harvest fungal pathogens of Cowpea legumes. Aqueous leaves extract of Parthenium hysterophorus, Annona reticulata, Polyalthia longifolia, Ipomea carnea, Tridax procumbens, Argemone mexicana, Cathranthus roseus, Eucalyptus globulus and Achyranthus aspera were used against the post harvest fungal mycoflora. All the plants used were found to be antifungal. In particular Eucalyptus globulus, Argemone mexicana, Tridax procumbens and Parthenium hysterophorus were highly inhibitory. These plant extracts can be used for controlling fungal pathogens of Cowpea legumes during post harvest as these are eco-friendly and do not cause environmental hazard.

  7. Study of Pathogens of Fungal Keratitis and the Sensitivity of Pathogenic Fungi to Therapeutic Agents with the Disk Diffusion Method.

    Science.gov (United States)

    Wang, Lulu; Wang, Liya; Han, Lei; Yin, Weijing

    2015-01-01

    To identify the causative fungi of fungal keratitis, test their susceptibility to antifungal agents with the disk diffusion method and study the relationship between the organisms, the inhibition zones and the clinical outcomes. 535 patients with fungal keratitis in one eye were included in this study. Pathogenic fungi were isolated by corneal scraping, identified by fungal cultivation and subjected to drug sensitivity tests conducted with the disk diffusion method. The patients were treated initially with voriconazole, terbinafine and natamycin eye drops for one week. Further treatment continued using the most effective drug according to the drug sensitivity results. The patients were followed up every week until three months after cured. The inhibition zones of fungi cultured with voriconazole, terbinafine and natamycin were compared. The relationship between inhibition zones and organism, organism and treatment results measure, and each treatment results measure and inhibition zones were evaluated. Of 535 patients, 53.84%, 19.25% and 26.91% were infected with Aspergillus, Fusarium and other fungi, respectively. Keratitis patients infected with Aspergillus keratitis had the worst outcome. The size of the inhibition zones of Aspergillus spp., Fusarium spp. and other fungal genera differed significantly in response to voriconazole, terbinafine and natamycin. The inhibition zone associated with natamycin correlated significantly with the clinical outcome of fungal keratitis (OR = 0.925), but no other such correlations were found for the other drugs tested. Aspergillus and Fusarium were the predominant pathogenic genera causing fungal keratitis in our patients. Among the causative fungi, infections due to Aspergillus spp. were associated with the worst outcomes. The inhibition zones of fungal isolates in response to natamycin significantly correlated with the treatment outcomes of keratitis. Specifically, the smaller the natamycin inhibition zone, the lower the

  8. Polyethylene glycol (PEG)-mediated transformation in filamentous fungal pathogens

    Science.gov (United States)

    Genetic transformation is an essential tool in molecular biology for many purposes including the study of gene function and the genetic improvement of an organism. The genetic transformation of many fungal species is a well established process that can be carried out by utilizing different transform...

  9. Adhesins in Human Fungal Pathogens : Glue with Plenty of Stick

    NARCIS (Netherlands)

    de Groot, Piet W. J.; Bader, Oliver; de Boer, Albert D.; Weig, Michael; Chauhan, Neeraj

    2013-01-01

    Understanding the pathogenesis of an infectious disease is critical for developing new methods to prevent infection and diagnose or cure disease. Adherence of microorganisms to host tissue is a prerequisite for tissue invasion and infection. Fungal cell wall adhesins involved in adherence to host ti

  10. Determination of fungal pathogens of common weed species in the vicinity of Tokat, Turkey.

    Science.gov (United States)

    Kadioğlu, I; Karamanli, N; Yanar, Y

    2010-01-01

    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.

  11. Pathogenic spectrum of fungal keratitis and specific identification of Fusarium solani.

    Science.gov (United States)

    He, Dan; Hao, Jilong; Zhang, Bo; Yang, Yanqiu; Song, Wengang; Zhang, Yunfeng; Yokoyama, Koji; Wang, Li

    2011-04-25

    To investigate the predominant causative pathogens and epidemiologic features of fungal keratitis and establish a rapid, specific molecular method to detect fungal keratitis caused by Fusarium solani. A total of 174 patients with presumed fungal keratitis and 174 affected eyes were examined. Isolates from corneal specimens were identified according to morphologic and physiological characteristics. The primers that were designed for F. solani were tested to confirm whether they had species specificity. Multiplex PCR with universal fungal and F. solani-specific primers was performed with fungal and bacterial strains and was used to detect microorganisms in the clinical specimens. A total of 160 patients (92.0%) were diagnosed with fungal infection by either potassium hydroxide wet-mount or microbiologic culture. Fungal cultures were positive in 128 patients (73.6%) with 139 fungal isolates. Fusarium (48.2%) was the most frequently isolated genus, in which F. solani (35.2%) was the most common species, followed by the Aspergillus (18.7%) and Candida (16.6%) genera. The PCR results showed that the designed primers were species specific and suitable for specific identification of F. solani. The multiplex PCR of 3-day broth cultures could identify and distinguish F. solani from other pathogens rapidly and specifically from clinical specimens. Fusarium species, especially F. solani, were found to be the predominant cause of fungal keratitis in northeast China. The established multiplex PCR method could have potential advantages for rapid detection of F. solani. These findings might have significance for early diagnosis and treatment of fungal keratitis.

  12. Diversidad genetica de aislamientos de cornezuelo (Claviceps africana fredrickson, mantle, y de milliano) de sorgo [Sorghum bicolor (l.) moench.] en Mexico

    Science.gov (United States)

    This study was conducted in Rio Bravo, Tamaulipas, and Celaya, Guanajuato, Mexico, in which pathogenicity of two isolates of ergot (Claviceps africana) obtained from the same two locations, were evaluated on six hybrids and three male sterile sorghum lines. Also, a genetic variance indicated signif...

  13. Aerially transmitted human fungal pathogens: what can we learn from metagenomics and comparative genomics?

    Science.gov (United States)

    Aliouat-Denis, Cécile-Marie; Chabé, Magali; Delhaes, Laurence; Dei-Cas, Eduardo

    2014-01-01

    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).

  14. Field tolerance to fungal pathogens of Brassica napus constitutively expressing a chimeric chitinase gene

    Energy Technology Data Exchange (ETDEWEB)

    Grison, R.; Grezes-Besset, B.; Lucante, N. [Rustica Prograin Genetique, Mondonville (France)] [and others

    1996-05-01

    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.

  15. Schizophyllum commune: an emergent or misdiagnosed fungal pathogen in rhinology?

    Science.gov (United States)

    Michel, Justin; Maubon, Danièle; Varoquaux, Damien Arthur; Boulze, Carole; Normand, Anne Cécile; Righini, Christian Adrien; Piarroux, Renaud; Dessi, Patrick; Ranque, Stéphane

    2016-03-01

    Schizophyllum commune is a common basidiomycete fungus that is rarely involved in human disease. The medical records of patients operated on for fungal rhinosinusitis (FRS) in two University Hospitals between 2012 and 2014 were reviewed. Within the two-year survey, six female, and notably no male, patients were diagnosed with S. commune rhinosinusitis. Mean age was 44.6 years at diagnosis (30 to 68 years). Mean time between onset of symptoms and diagnosis was 8.5 months (2 to 12 months). All six patients were immunocompetent and had no particular host factor for FRS. S. commune was identified using MALDI-TOF mass spectrometry and identifications were confirmed via DNA sequence analysis. Chronic invasive fungal rhinosinusitis was diagnosed in three of our six patients. Based on histological findings, antifungal treatment was delivered in association with surgery. The basidiomycete fungus S. commune is an emerging cause of rhinosinusitis probably as a direct consequence of the recent technological progress in fungal identification methods (DNA sequencing and MALDI-TOF mass spectrometry). © The Author 2015. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  16. Life histories of hosts and pathogens predict patterns in tropical fungal plant diseases.

    Science.gov (United States)

    García-Guzmán, Graciela; Heil, Martin

    2014-03-01

    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.

  17. Systematic characterization of the peroxidase gene family provides new insights into fungal pathogenicity in Magnaporthe oryzae.

    Science.gov (United States)

    Mir, Albely Afifa; Park, Sook-Young; Abu Sadat, Md; Kim, Seongbeom; Choi, Jaeyoung; Jeon, Junhyun; Lee, Yong-Hwan

    2015-07-02

    Fungal pathogens have evolved antioxidant defense against reactive oxygen species produced as a part of host innate immunity. Recent studies proposed peroxidases as components of antioxidant defense system. However, the role of fungal peroxidases during interaction with host plants has not been explored at the genomic level. Here, we systematically identified peroxidase genes and analyzed their impact on fungal pathogenesis in a model plant pathogenic fungus, Magnaporthe oryzae. Phylogeny reconstruction placed 27 putative peroxidase genes into 15 clades. Expression profiles showed that majority of them are responsive to in planta condition and in vitro H2O2. Our analysis of individual deletion mutants for seven selected genes including MoPRX1 revealed that these genes contribute to fungal development and/or pathogenesis. We identified significant and positive correlations among sensitivity to H2O2, peroxidase activity and fungal pathogenicity. In-depth analysis of MoPRX1 demonstrated that it is a functional ortholog of thioredoxin peroxidase in Saccharomyces cerevisiae and is required for detoxification of the oxidative burst within host cells. Transcriptional profiling of other peroxidases in ΔMoprx1 suggested interwoven nature of the peroxidase-mediated antioxidant defense system. The results from this study provide insight into the infection strategy built on evolutionarily conserved peroxidases in the rice blast fungus.

  18. Plant Phenotypic and Transcriptional Changes Induced by Volatiles from the Fungal Root Pathogen Rhizoctonia solani

    Science.gov (United States)

    Cordovez, Viviane; Mommer, Liesje; Moisan, Kay; Lucas-Barbosa, Dani; Pierik, Ronald; Mumm, Roland; Carrion, Victor J.; Raaijmakers, Jos M.

    2017-01-01

    Beneficial soil microorganisms can affect plant growth and resistance by the production of volatile organic compounds (VOCs). Yet, little is known on how VOCs from soil-borne plant pathogens affect plant growth and resistance. Here we show that VOCs released from mycelium and sclerotia of the fungal root pathogen Rhizoctonia solani enhance growth and accelerate development of Arabidopsis thaliana. Seedlings briefly exposed to the fungal VOCs showed similar phenotypes, suggesting that enhanced biomass and accelerated development are primed already at early developmental stages. Fungal VOCs did not affect plant resistance to infection by the VOC-producing pathogen itself but reduced aboveground resistance to the herbivore Mamestra brassicae. Transcriptomics of A. thaliana revealed that genes involved in auxin signaling were up-regulated, whereas ethylene and jasmonic acid signaling pathways were down-regulated by fungal VOCs. Mutants disrupted in these pathways showed similar VOC-mediated growth responses as the wild-type A. thaliana, suggesting that other yet unknown pathways play a more prominent role. We postulate that R. solani uses VOCs to predispose plants for infection from a distance by altering root architecture and enhancing root biomass. Alternatively, plants may use enhanced root growth upon fungal VOC perception to sacrifice part of the root biomass and accelerate development and reproduction to survive infection. PMID:28785271

  19. Genome Sequencing and Comparative Genomics Analysis Revealed Pathogenic Potential in Penicillium capsulatum as a Novel Fungal Pathogen Belonging to Eurotiales

    Science.gov (United States)

    Yang, Ying; Chen, Min; Li, Zongwei; Al-Hatmi, Abdullah M. S.; de Hoog, Sybren; Pan, Weihua; Ye, Qiang; Bo, Xiaochen; Li, Zhen; Wang, Shengqi; Wang, Junzhi; Chen, Huipeng; Liao, Wanqing

    2016-01-01

    Penicillium capsulatum is a rare Penicillium species used in paper manufacturing, but recently it has been reported to cause invasive infection. To research the pathogenicity of the clinical Penicillium strain, we sequenced the genomes and transcriptomes of the clinical and environmental strains of P. capsulatum. Comparative analyses of these two P. capsulatum strains and close related strains belonging to Eurotiales were performed. The assembled genome sizes of P. capsulatum are approximately 34.4 Mbp in length and encode 11,080 predicted genes. The different isolates of P. capsulatum are highly similar, with the exception of several unique genes, INDELs or SNPs in the genes coding for glycosyl hydrolases, amino acid transporters and circumsporozoite protein. A phylogenomic analysis was performed based on the whole genome data of 38 strains belonging to Eurotiales. By comparing the whole genome sequences and the virulence-related genes from 20 important related species, including fungal pathogens and non-human pathogens belonging to Eurotiales, we found meaningful pathogenicity characteristics between P. capsulatum and its closely related species. Our research indicated that P. capsulatum may be a neglected opportunistic pathogen. This study is beneficial for mycologists, geneticists and epidemiologists to achieve a deeper understanding of the genetic basis of the role of P. capsulatum as a newly reported fungal pathogen. PMID:27761131

  20. Molecular characterization and pathogenicity of fungal isolates for use against the small hive beetle (Aethina tumida)

    Science.gov (United States)

    The analysis of DNA sequences from fungal pathogens obtained from cadavers of the small hive beetle (SHB) collected from several apiaries in Florida revealed a mixture of saprobes and two potential primary entomopathogens, Metarhizium anisopliae and Beauveria bassiana. Spray tower bioassays indicate...

  1. Insight into tradeoff between wood decay and parasitism from the genome of a fungal forest pathogen

    Science.gov (United States)

    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

    2012-01-01

    • 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...

  2. Evaluation of the pathogenic effect of some fungal isolates on fruits ...

    African Journals Online (AJOL)

    Abstract. Laboratory and screenhouse experiments were carried out to identify and ... Pathogenicity tests on fresh pepper fruits in –vitro revealed that all the fungal ... symptom response in the form of initial necrotic spots on the leaves and then ...

  3. Insights into molecular and metabolic events associated with fruit response to postharvest fungal pathogens

    Directory of Open Access Journals (Sweden)

    Noam eAlkan

    2015-10-01

    Full Text Available Due to postharvest 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 postharvest fungal pathogens during fruit ripening.

  4. Insights into molecular and metabolic events associated with fruit response to post-harvest fungal pathogens.

    Science.gov (United States)

    Alkan, Noam; Fortes, Ana M

    2015-01-01

    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.

  5. Growth inhibitory effects of gossypol and related compounds on fungal cotton root pathogens

    Science.gov (United States)

    The aim of this study was to investigate the effects of terpenoids gossypol, gossypolone, apogossypolone, methoxygossypol and dimethoxygossypol on growth of a collection of fungal soil pathogens. The compounds were tested at a concentration of 100 µg ml-1 in a Czapek Dox agar medium at 25°C. Gossy...

  6. Mycetoma fungal infection: multiple organisms as colonizers or pathogens?

    Science.gov (United States)

    Pilsczek, Florian H; Augenbraun, Michael

    2007-01-01

    We describe a patient with mycetoma or Madura foot, in which histopathological stains of the bone and surface cultures suggested three different organisms including Nocardia species as the cause. Criteria for the diagnosis of the organisms, differentiation between colonizer and pathogen, and significance of mixed infections are discussed.

  7. Culture collections, the new herbaria for fungal pathogens

    NARCIS (Netherlands)

    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.

    2010-01-01

    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 f

  8. A critical role of autophagy in plant resistance to necrotrophic fungal pathogens.

    Science.gov (United States)

    Lai, Zhibing; Wang, Fei; Zheng, Zuyu; Fan, Baofang; Chen, Zhixiang

    2011-06-01

    Autophagy is a pathway for degradation of cytoplasmic components. In plants, autophagy plays an important role in nutrient recycling during nitrogen or carbon starvation, and in responses to abiotic stress. Autophagy also regulates age- and immunity-related programmed cell death, which is important in plant defense against biotrophic pathogens. Here we show that autophagy plays a critical role in plant resistance to necrotrophic pathogens. ATG18a, a critical autophagy protein in Arabidopsis, interacts with WRKY33, a transcription factor that is required for resistance to necrotrophic pathogens. Expression of autophagy genes and formation of autophagosomes are induced in Arabidopsis by the necrotrophic fungal pathogen Botrytis cinerea. Induction of ATG18a and autophagy by B. cinerea was compromised in the wrky33 mutant, which is highly susceptible to necrotrophic pathogens. Arabidopsis mutants defective in autophagy exhibit enhanced susceptibility to the necrotrophic fungal pathogens B. cinerea and Alternaria brassicicola based on increased pathogen growth in the mutants. The hypersusceptibility of the autophagy mutants was associated with reduced expression of the jasmonate-regulated PFD1.2 gene, accelerated development of senescence-like chlorotic symptoms, and increased protein degradation in infected plant tissues. These results strongly suggest that autophagy cooperates with jasmonate- and WRKY33-mediated signaling pathways in the regulation of plant defense responses to necrotrophic pathogens.

  9. A fungal symbiont of plant-roots modulates mycotoxin gene expression in the pathogen Fusarium sambucinum.

    Directory of Open Access Journals (Sweden)

    Youssef Ismail

    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.

  10. A fungal symbiont of plant-roots modulates mycotoxin gene expression in the pathogen Fusarium sambucinum.

    Science.gov (United States)

    Ismail, Youssef; McCormick, Susan; Hijri, Mohamed

    2011-03-24

    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.

  11. Fungal pathogens associated with banana fruit in Sri Lanka, and their treatment with essential oils.

    Science.gov (United States)

    Anthony, Sulali; Abeywickrama, Krishanthi; Dayananda, Ranjith; Wijeratnam, Shanthi Wilson; Arambewela, Luxshmi

    2004-01-01

    The crown rot pathogens isolated from banana samples collected from 12 localities in Sri Lanka were Lasiodiplodia theobromae, Fusarium proliferatum and Colletotrichum musae. Fungal pathogens isolated were able to cause crown rot disease alone or in combination. Disease severity was higher when combinations of virulent pathogens were used. Cymbopogon nardus and Ocimum basilicum oils displayed fungicidal activity against C. musae and F. proliferatum between 0.2-0.6% (v/v) in a Poisoned food bioassay. Slightly lower concentrations of the test oils were needed for similar activity during liquid bioassays. The combination of Cymbopogon nardus and O. basilicum oils demonstrated synergistic action during both in-vivo bioassays.

  12. Cutaneous Aspergillus ustus in a lung transplant recipient: emergence of a new opportunistic fungal pathogen.

    Science.gov (United States)

    Vagefi, Parsia A; Cosimi, A Benedict; Ginns, Leo C; Kotton, Camille N

    2008-01-01

    Opportunistic fungal infections remain a significant complication in immunosuppressed patients, especially those having undergone solid-organ transplantation. We report a 39-year-old patient who represents the second case of cutaneous Aspergillus ustus infection in a solid-organ transplant recipient, and the first documented case after lung transplantation. The patient's cutaneous lower extremity aspergillosis responded to a combination of intravenous liposomal amphotericin B, caspofungin and topical terbinafine cream, with a concomitant reduction in immunosuppression. A. ustus is an emerging opportunistic fungal pathogen in transplant recipients.

  13. Rhizobia: a potential biocontrol agent for soilborne fungal pathogens.

    Science.gov (United States)

    Das, Krishnashis; Prasanna, Radha; Saxena, Anil Kumar

    2017-03-12

    Rhizobia are a group of organisms that are well known for their ability to colonize root surfaces and form symbiotic associations with legume plants. They not only play a major role in biological nitrogen fixation but also improve plant growth and reduce disease incidence in various crops. Rhizobia are known to control the growth of many soilborne plant pathogenic fungi belonging to different genera like Fusarium, Rhizoctonia, Sclerotium, and Macrophomina. Antagonistic activity of rhizobia is mainly attributed to production of antibiotics, hydrocyanic acid (HCN), mycolytic enzymes, and siderophore under iron limiting conditions. Rhizobia are also reported to induce systemic resistance and enhance expression of plant defense-related genes, which effectively immunize the plants against pathogens. Seed bacterization with appropriate rhizobial strain leads to elicitation and accumulation of phenolic compounds, isoflavonoid phytoalexins, and activation of enzymes like L-phenylalanine ammonia lyase (PAL), chalcone synthase (CHS), peroxidase (POX), polyphenol oxidase (PPO), and others involved in phenylpropanoid and isoflavonoid pathways. Development of Rhizobium inoculants with dual attributes of nitrogen fixation and antagonism against phytopathogens can contribute to increased plant growth and productivity. This compilation aims to bring together the available information on the biocontrol facet of rhizobia and identify research gaps and effective strategies for future research in this area.

  14. Evolution of pathogenicity traits in the apple scab fungal pathogen in response to the domestication of its host.

    Science.gov (United States)

    Lê Van, Amandine; Gladieux, Pierre; Lemaire, Christophe; Cornille, Amandine; Giraud, Tatiana; Durel, Charles-Eric; Caffier, Valérie; Le Cam, Bruno

    2012-11-01

    Understanding how pathogens emerge is essential to bring disease-causing agents under durable human control. Here, we used cross-pathogenicity tests to investigate the changes in life-history traits of the fungal pathogen Venturia inaequalis associated with host-tracking during the domestication of apple and subsequent host-range expansion on the wild European crabapple (Malus sylvestris). Pathogenicity of 40 isolates collected in wild and domesticated ecosystems was assessed on the domesticated apple, its Central Asian main progenitor (M. sieversii) and M. sylvestris. Isolates from wild habitats in the centre of origin of the crop were not pathogenic on the domesticated apple and less aggressive than other isolates on their host of origin. Isolates from the agro-ecosystem in Central Asia infected a higher proportion of plants with higher aggressiveness, on both the domesticated host and its progenitor. Isolates from the European crabapple were still able to cause disease on other species but were less aggressive and less frequently virulent on these hosts than their endemic populations. Our results suggest that the domestication of apple was associated with the acquisition of virulence in the pathogen following host-tracking. The spread of the disease in the agro-ecosystem would also have been accompanied by an increase in overall pathogenicity.

  15. Imaging O2 changes induced in tomato roots by fungal pathogen

    Science.gov (United States)

    Rubol, S.; Turco, E.; Rodeghiero, M.; Bellin, A.

    2014-12-01

    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.

  16. Sporothrix schenckii complex biology: environment and fungal pathogenicity.

    Science.gov (United States)

    Téllez, M D; Batista-Duharte, A; Portuondo, D; Quinello, C; Bonne-Hernández, R; Carlos, I Z

    2014-11-01

    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.

  17. Integrating large-scale data and RNA technology to protect crops from fungal pathogens

    Directory of Open Access Journals (Sweden)

    Ian Joseph Girard

    2016-05-01

    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.

  18. Targeted Gene Replacement in Fungal Pathogens via Agrobacterium tumefaciens- Mediated Transformation

    DEFF Research Database (Denmark)

    Frandsen, Rasmus John Normand; Frandsen, Mette; Giese, Nanna Henriette

    2012-01-01

    Genome sequence data on fungal pathogens provide the opportunity to carry out a reverse genetics approach to uncover gene function. Efficient methods for targeted genome modifications such as knockout and in locus over-expression are in high demand. Here we describe two efficient single...... 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....... The cloning systems described above are relevant for all transformation vector constructs, but here we describe their application for ATMT compatible binary vectors. Protocols are provided for ATMT exemplified by Fusarium graminearum. For large-scale reverse genetic projects, the USER technology...

  19. Three promising fungal strains pathogenic to fruit flies

    Energy Technology Data Exchange (ETDEWEB)

    Jiji, T.; Praveena, R.; Babu, Kavitha; Naseema, A.; Anitha, N. [College of Agriculture, Kerala (India)

    2006-07-01

    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)

  20. Identification of fungal pathogens in Formalin-fixed, Paraffin-embedded tissue samples by molecular methods.

    Science.gov (United States)

    Rickerts, Volker

    2016-02-01

    The etiology of invasive fungal infections (IFI) is incompletely understood due to diagnostic limitations including insensitivity of cultures and failure of histopathology to discriminate between different species. This diagnostic gap precludes the optimal use of antifungals, leading to adverse patient outcomes. The identification of fungal pathogens from Formalin-fixed, Paraffin-embedded tissue (FFPE) blocks by molecular methods is emerging as an alternative approach to study the etiology of IFI. PCR assays, including species specific- and broadrange fungal tests are used with FFPE samples from patients with proven IFI. Fungal species identification is achieved in 15-90% of the samples. This heterogeneity may be explained by the samples studied. However, comparison of different studies is impaired, as controls ruling out false positive-, false negative test results or PCR inhibition are frequently not reported. Studies using in situ hybridization also vary in the clinical samples included and the targeted fungi. In addition, target sequences, the probe chemistry and the detection of hybridization signals also account for the differences in diagnostic sensitivity. Using both approaches in parallel yields additive insights, potentially leading to a superior identification of fungal etiology and awareness of the limitations of both molecular diagnostic approaches.

  1. Fungal Mimicry of a Mammalian Aminopeptidase Disables Innate Immunity and Promotes Pathogenicity.

    Science.gov (United States)

    Sterkel, Alana K; Lorenzini, Jenna L; Fites, J Scott; Subramanian Vignesh, Kavitha; Sullivan, Thomas D; Wuthrich, Marcel; Brandhorst, Tristan; Hernandez-Santos, Nydiaris; Deepe, George S; Klein, Bruce S

    2016-03-09

    Systemic fungal infections trigger marked immune-regulatory disturbances, but the mechanisms are poorly understood. We report that the pathogenic yeast of Blastomyces dermatitidis elaborates dipeptidyl-peptidase IVA (DppIVA), a close mimic of the mammalian ectopeptidase CD26, which modulates critical aspects of hematopoiesis. We show that, like the mammalian enzyme, fungal DppIVA cleaved C-C chemokines and GM-CSF. Yeast producing DppIVA crippled the recruitment and differentiation of monocytes and prevented phagocyte activation and ROS production. Silencing fungal DppIVA gene expression curtailed virulence and restored recruitment of CCR2(+) monocytes, generation of TipDC, and phagocyte killing of yeast. Pharmacological blockade of DppIVA restored leukocyte effector functions and stemmed infection, while addition of recombinant DppIVA to gene-silenced yeast enabled them to evade leukocyte defense. Thus, fungal DppIVA mediates immune-regulatory disturbances that underlie invasive fungal disease. These findings reveal a form of molecular piracy by a broadly conserved aminopeptidase during disease pathogenesis.

  2. Control of the sheep scab mite Psoroptes ovis in vivo and in vitro using fungal pathogens.

    Science.gov (United States)

    Abolins, S; Thind, B; Jackson, V; Luke, B; Moore, D; Wall, R; Taylor, M A

    2007-09-30

    As part of a research programme designed to identify biological agents for the control of sheep scab, the pathogenicity of the fungus Metarhizium anisopliae to Psoroptes mites in the presence of sheepskin and wool was examined in the laboratory. No inhibitory effects of skin and wool were observed and high levels of infection were recorded. Subsequently the pathogenicity of formulations of both M. anisopliae and Beauveria bassiana to Psoroptes ovis was studied in vivo. For this, 36 batches of 20 adult female Psoroptes mites were confined in 25 mm diameter chambers which were attached to the backs of 6 scab-naive sheep. In some treatments, mites were exposed to the fungal pathogens for 48 h in vitro prior to being placed on the host, while other treatments involved mites with no prior exposure placed directly onto the skin of a host treated with a fungal pathogen. After 48 h on the host, mites were removed, incubated individually and all fungal infections were recorded. Fungal infection was observed in all treatments, except untreated controls. However, B. bassiana infected a significantly greater number of mites than M. anisopliae with all the formulations examined. Infection rates were highest when mites were exposed to dry conidia (>90%) and lowest with M. anisopliae in diatomaceous earth. Overall, the infection rate was not affected by whether or not the mites were given prior exposure to the conidia, before being placed on the sheep. The results demonstrate that Psoroptes mites can become infected by entomopathogenic fungi on the skin of sheep and provides a first demonstration of the potential of this technology for the control of sheep scab.

  3. Aspergillus sydowii and Other Potential Fungal Pathogens in Gorgonian Octocorals of the Ecuadorian Pacific

    Science.gov (United States)

    Soler-Hurtado, M. Mar; Sandoval-Sierra, José Vladimir; Machordom, Annie; Diéguez-Uribeondo, Javier

    2016-01-01

    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. PMID:27902710

  4. Arabidopsis WRKY33 transcription factor is required for resistance to necrotrophic fungal pathogens.

    Science.gov (United States)

    Zheng, Zuyu; Qamar, Synan Abu; Chen, Zhixiang; Mengiste, Tesfaye

    2006-11-01

    Plant WRKY transcription factors are key regulatory components of plant responses to microbial infection. In addition to regulating the expression of defense-related genes, WRKY transcription factors have also been shown to regulate cross-talk between jasmonate- and salicylate-regulated disease response pathways. The two pathways mediate resistance against different types of microbial pathogens, and there are numerous reports of antagonistic interactions between them. Here we show that mutations of the Arabidopsis WRKY33 gene encoding a WRKY transcription factor cause enhanced susceptibility to the necrotrophic fungal pathogens Botrytis cinerea and Alternaria brassicicola concomitant with reduced expression of the jasmonate-regulated plant defensin PDF1.2 gene. Ectopic over-expression of WRKY33, on the other hand, increases resistance to the two necrotrophic fungal pathogens. The wrky33 mutants do not show altered responses to a virulent strain of the bacterial pathogen Pseudomonas syringae, although the ectopic expression of WRKY33 results in enhanced susceptibility to this pathogen. The susceptibility of WRKY33-over-expressing plants to P. syringae is associated with reduced expression of the salicylate-regulated PR-1 gene. The WRKY33 transcript is induced in response to pathogen infection, or treatment with salicylate or the paraquat herbicide that generates activated oxygen species in exposed cells. WRKY33 is localized to the nucleus of plant cells and recognizes DNA molecules containing the TTGACC W-box sequence. Together, these results indicate that pathogen-induced WRKY33 is an important transcription factor that regulates the antagonistic relationship between defense pathways mediating responses to P. syringae and necrotrophic pathogens.

  5. Modelling fungal sink competitiveness with grains for assimilates in wheat infected by a biotrophic pathogen.

    Science.gov (United States)

    Bancal, Marie-Odile; Hansart, Amandine; Sache, Ivan; Bancal, Pierre

    2012-07-01

    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. 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. 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 duration of grain filling. Source-sink modelling

  6. Temperature dependent virulence of obligate and facultative fungal pathogens of honeybee brood.

    Science.gov (United States)

    Vojvodic, S; Jensen, A B; James, R R; Boomsma, J J; Eilenberg, J

    2011-04-21

    Chalkbrood (Ascosphaera apis) and stonebrood (Aspergillus flavus) are well known fungal brood diseases of honeybees (Apis mellifera), but they have hardly been systematically studied because the difficulty of rearing larvae in vitro has precluded controlled experimentation. Chalkbrood is a chronic honeybee-specific disease that can persist in colonies for years, reducing both brood and honey production, whereas stonebrood is a rare facultative pathogen that also affects hosts other than honeybees and can likely survive outside insect hosts. Hive infection trials have indicated that accidental drops in comb temperature increase the prevalence of chalkbrood, but it has remained unclear whether virulence is directly temperature-dependent. We used a newly established in vitro rearing technique for honeybee larvae to test whether there are systematic temperature effects on mortality induced by controlled infections, and whether such effects differed between the two fungal pathogens. We found that increasing spore dosage at infection had a more dramatic effect on mortality from stonebrood compared to chalkbrood. In addition, a 24h cooling period after inoculation increased larval mortality from chalkbrood infection, whereas such a cooling period decreased mortality after stonebrood infection. These results raise interesting questions about honeybee defenses against obligate and facultative pathogens and about the extent to which stress factors in the host (dis)favor pathogens with lesser degrees of specialization. Copyright © 2010 Elsevier B.V. All rights reserved.

  7. Fungal life-styles and ecosystem dynamics: biological aspects of plant pathogens, plant endophytes and saprophytes

    Science.gov (United States)

    Rodriguez, R.J.; Redman, R.S.

    1997-01-01

    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.

  8. Recent developments in pathogen detection arrays: implications for fungal plant pathogens and use in practica

    NARCIS (Netherlands)

    Lievens, B.; Thomma, B.P.H.J.

    2005-01-01

    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, an

  9. Comparative genomics allowed the identification of drug targets against human fungal pathogens

    Directory of Open Access Journals (Sweden)

    Martins Natalia F

    2011-01-01

    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

  10. Nanoscale biophysical properties of the cell surface galactosaminogalactan from the fungal pathogen Aspergillus fumigatus.

    Science.gov (United States)

    Beaussart, Audrey; El-Kirat-Chatel, Sofiane; Fontaine, Thierry; Latgé, Jean-Paul; Dufrêne, Yves F

    2015-09-28

    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.

  11. Structures of Cryptococcus neoformans protein farnesyltransferase reveal strategies for developing inhibitors that target fungal pathogens.

    Science.gov (United States)

    Hast, Michael A; Nichols, Connie B; Armstrong, Stephanie M; Kelly, Shannon M; Hellinga, Homme W; Alspaugh, J Andrew; Beese, Lorena S

    2011-10-07

    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.

  12. Structures of Cryptococcus neoformans Protein Farnesyltransferase Reveal Strategies for Developing Inhibitors That Target Fungal Pathogens

    Energy Technology Data Exchange (ETDEWEB)

    Hast, Michael A.; Nichols, Connie B.; Armstrong, Stephanie M.; Kelly, Shannon M.; Hellinga, Homme W.; Alspaugh, J. Andrew; Beese, Lorena S. (Duke)

    2012-09-17

    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.

  13. Isolation and characterization of soil Streptomyces species as potential biological control agents against fungal plant pathogens.

    Science.gov (United States)

    Evangelista-Martínez, Zahaed

    2014-05-01

    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.

  14. Fungal Inositol Pyrophosphate IP7 Is Crucial for Metabolic Adaptation to the Host Environment and Pathogenicity

    Science.gov (United States)

    Lev, Sophie; Li, Cecilia; Desmarini, Desmarini; Saiardi, Adolfo; Fewings, Nicole L.; Schibeci, Stephen D.; Sharma, Raghwa; Sorrell, Tania C.

    2015-01-01

    ABSTRACT Inositol pyrophosphates (PP-IPs) comprising inositol, phosphate, and pyrophosphate (PP) are essential for multiple functions in eukaryotes. Their role in fungal pathogens has never been addressed. Cryptococcus neoformans is a model pathogenic fungus causing life-threatening meningoencephalitis. We investigate the cryptococcal kinases responsible for the production of PP-IPs (IP7/IP8) and the hierarchy of PP-IP importance in pathogenicity. Using gene deletion and inositol polyphosphate profiling, we identified Kcs1 as the major IP6 kinase (producing IP7) and Asp1 as an IP7 kinase (producing IP8). We show that Kcs1-derived IP7 is the most crucial PP-IP for cryptococcal drug susceptibility and the production of virulence determinants. In particular, Kcs1 kinase activity is essential for cryptococcal infection of mouse lungs, as reduced fungal burdens were observed in the absence of Kcs1 or when Kcs1 was catalytically inactive. Transcriptome and carbon source utilization analysis suggested that compromised growth of the KCS1 deletion strain (Δkcs1 mutant) in the low-glucose environment of the host lung is due to its inability to utilize alternative carbon sources. Despite this metabolic defect, the Δkcs1 mutant established persistent, low-level asymptomatic pulmonary infection but failed to elicit a strong immune response in vivo and in vitro and was not readily phagocytosed by primary or immortalized monocytes. Reduced recognition of the Δkcs1 cells by monocytes correlated with reduced exposure of mannoproteins on the Δkcs1 mutant cell surface. We conclude that IP7 is essential for fungal metabolic adaptation to the host environment, immune recognition, and pathogenicity. PMID:26037119

  15. The Evolution of Orphan Regions in Genomes of a Fungal Pathogen of Wheat

    Directory of Open Access Journals (Sweden)

    Clémence Plissonneau

    2016-10-01

    Full Text Available Fungal plant pathogens rapidly evolve virulence on resistant hosts through mutations in genes encoding proteins that modulate the host immune responses. The mutational spectrum likely includes chromosomal rearrangements responsible for gains or losses of entire genes. However, the mechanisms creating adaptive structural variation in fungal pathogen populations are poorly understood. We used complete genome assemblies to quantify structural variants segregating in the highly polymorphic fungal wheat pathogen Zymoseptoria tritici. The genetic basis of virulence in Z. tritici is complex, and populations harbor significant genetic variation for virulence; hence, we aimed to identify whether structural variation led to functional differences. We combined single-molecule real-time sequencing, genetic maps, and transcriptomics data to generate a fully assembled and annotated genome of the highly virulent field isolate 3D7. Comparative genomics analyses against the complete reference genome IPO323 identified large chromosomal inversions and the complete gain or loss of transposable-element clusters, explaining the extensive chromosomal-length polymorphisms found in this species. Both the 3D7 and IPO323 genomes harbored long tracts of sequences exclusive to one of the two genomes. These orphan regions contained 296 genes unique to the 3D7 genome and not previously known for this species. These orphan genes tended to be organized in clusters and showed evidence of mutational decay. Moreover, the orphan genes were enriched in genes encoding putative effectors and included a gene that is one of the most upregulated putative effector genes during wheat infection. Our study showed that this pathogen species harbored extensive chromosomal structure polymorphism that may drive the evolution of virulence.

  16. Plant pathogens but not antagonists change in soil fungal communities across a land abandonment gradient in a Mediterranean landscape

    Science.gov (United States)

    Bosso, L.; Lacatena, F.; Varlese, R.; Nocerino, S.; Cristinzio, G.; Russo, D.

    2017-01-01

    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.

  17. Drought Impact on the Soilborne Fungal Pathogen of Tomato: Fusarium Oxysporum f. sp. Lycopersici Race 3

    Science.gov (United States)

    Raju, T.

    2016-12-01

    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

  18. Facing the challenges of multiscale modelling of bacterial and fungal pathogen-host interactions.

    Science.gov (United States)

    Schleicher, Jana; Conrad, Theresia; Gustafsson, Mika; Cedersund, Gunnar; Guthke, Reinhard; Linde, Jörg

    2017-03-01

    Recent and rapidly evolving progress on high-throughput measurement techniques and computational performance has led to the emergence of new disciplines, such as systems medicine and translational systems biology. At the core of these disciplines lies the desire to produce multiscale models: mathematical models that integrate multiple scales of biological organization, ranging from molecular, cellular and tissue models to organ, whole-organism and population scale models. Using such models, hypotheses can systematically be tested. In this review, we present state-of-the-art multiscale modelling of bacterial and fungal infections, considering both the pathogen and host as well as their interaction. Multiscale modelling of the interactions of bacteria, especially Mycobacterium tuberculosis, with the human host is quite advanced. In contrast, models for fungal infections are still in their infancy, in particular regarding infections with the most important human pathogenic fungi, Candida albicans and Aspergillus fumigatus. We reflect on the current availability of computational approaches for multiscale modelling of host-pathogen interactions and point out current challenges. Finally, we provide an outlook for future requirements of multiscale modelling. © The Author 2016. Published by Oxford University Press.

  19. Induction of beta-1,3-glucanase in barley in response to infection by fungal pathogens.

    Science.gov (United States)

    Jutidamrongphan, W; Andersen, J B; Mackinnon, G; Manners, J M; Simpson, R S; Scott, K J

    1991-05-01

    The sequence of a partial cDNA clone corresponding to an mRNA induced in leaves of barley (Hordeum vulgare) by infection with fungal pathogens matched almost perfectly with that of a cDNA clone coding for beta-1,-3-glucanase isolated from the scutellum of barley. Western blot analysis of intercellular proteins from near-isogenic barley lines inoculated with the powdery mildew fungus (Erysiphe graminis f. sp. hordei) showed a strong induction of glucanase in all inoculated lines but was most pronounced in two resistant lines. These data were confirmed by beta-1,3-glucanase assays. The barley cDNA was used as a hybridization probe to detect mRNAs in barley, wheat (Triticum aestivum), rice (oryza sativus), and sorghum (Sorghum bicolor), which are induced by infection with the necrotrophic pathogen Bipolaris sorokiniana. These results demonstrate that activation of beta-1,3-glucanase genes may be a general response of cereals to infection by fungal pathogens.

  20. The GRF10 homeobox gene regulates filamentous growth in the human fungal pathogen Candida albicans.

    Science.gov (United States)

    Ghosh, Anup K; Wangsanut, Tanaporn; Fonzi, William A; Rolfes, Ronda J

    2015-12-01

    Candida albicans is the most common human fungal pathogen and can cause life-threatening infections. Filamentous growth is critical in the pathogenicity of C. albicans, as the transition from yeast to hyphal forms is linked to virulence and is also a pivotal process in fungal biofilm development. Homeodomain-containing transcription factors have been linked to developmental processes in fungi and other eukaryotes. We report here on GRF10, a homeobox transcription factor-encoding gene that plays a role in C. albicans filamentation. Deletion of the GRF10 gene, in both C. albicans SN152 and BWP17 strain backgrounds, results in mutants with strongly decreased hyphal growth. The mutants are defective in chlamydospore and biofilm formation, as well as showing dramatically attenuated virulence in a mouse infection model. Expression of the GRF10 gene is highly induced during stationary phase and filamentation. In summary, our study emphasizes a new role for the homeodomain-containing transcription factor in morphogenesis and pathogenicity of C. albicans.

  1. Molecular genetic characterisation of the Asc locus of tomato conferring resistance to the fungal pathogen Alternaria alternata f. sp. lycopersici

    NARCIS (Netherlands)

    Biezen, E.A. van der; Overduin, B.; Kneppers, T.J.A.; Mesbah, L.A.; Nijkamp, H.J.J.; Hille, J.

    1994-01-01

    The Alternaria stem canker disease of tomato is caused by the fungal pathogen Alternaria alternata f. sp. lycopersici and its host-selective AAL-toxins. Resistance to the pathogen and insensitivity to the toxins are conferred by the Asc locus on chromosome 3L. Sensitivity to AAL-toxins is a relative

  2. The expression of a bean PGIP in transgenic wheat confers increased resistance to the fungal pathogen Bipolaris sorokiniana.

    Science.gov (United States)

    Janni, Michela; Sella, Luca; Favaron, Francesco; Blechl, Ann E; De Lorenzo, Giulia; D'Ovidio, Renato

    2008-02-01

    A possible strategy to control plant pathogens is the improvement of natural plant defense mechanisms against the tools that pathogens commonly use to penetrate and colonize the host tissue. One of these mechanisms is represented by the host plant's ability to inhibit the pathogen's capacity to degrade plant cell wall polysaccharides. Polygalacturonase-inhibiting proteins (PGIP) are plant defense cell wall glycoproteins that inhibit the activity of fungal endopolygalacturonases (endo-PGs). To assess the effectiveness of these proteins in protecting wheat from fungal pathogens, we produced a number of transgenic wheat lines expressing a bean PGIP (PvPGIP2) having a wide spectrum of specificities against fungal PGs. Three independent transgenic lines were characterized in detail, including determination of the levels of PvPGIP2 accumulation and its subcellular localization and inhibitory activity. Results show that the transgene-encoded protein is correctly secreted into the apoplast, maintains its characteristic recognition specificities, and endows the transgenic wheat with new PG recognition capabilities. As a consequence, transgenic wheat tissue showed increased resistance to digestion by the PG of Fusarium moniliforme. These new properties also were confirmed at the plant level during interactions with the fungal pathogen Bipolaris sorokiniana. All three lines showed significant reductions in symptom progression (46 to 50%) through the leaves following infection with this pathogen. Our results illustrate the feasibility of improving wheat's defenses against pathogens by expression of proteins with new capabilities to counteract those produced by the pathogens.

  3. Lutein, a Natural Carotenoid, Induces α-1,3-Glucan Accumulation on the Cell Wall Surface of Fungal Plant Pathogens

    Directory of Open Access Journals (Sweden)

    Junnosuke Otaka

    2016-07-01

    Full Text Available α-1,3-Glucan, a component of the fungal cell wall, is a refractory polysaccharide for most plants. Previously, we showed that various fungal plant pathogens masked their cell wall surfaces with α-1,3-glucan to evade plant immunity. This surface accumulation of α-1,3-glucan was infection specific, suggesting that plant factors might induce its production in fungi. Through immunofluorescence observations of fungal cell walls, we found that carrot (Daucus carota extract induced the accumulation of α-1,3-glucan on germlings in Colletotrichum fioriniae, a polyphagous fungal pathogen that causes anthracnose disease in various dicot plants. Bioassay-guided fractionation of carrot leaf extract successfully identified two active substances that caused α-1,3-glucan accumulation in this fungus: lutein, a carotenoid widely distributed in plants, and stigmasterol, a plant-specific membrane component. Lutein, which had a greater effect on C. fioriniae, also induced α-1,3-glucan accumulation in other Colletotrichum species and in the phylogenetically distant rice pathogen Cochliobolus miyabeanus, but not in the rice pathogen Magnaporthe oryzae belonging to the same phylogenetic subclass as Colletotrichum. Our results suggested that fungal plant pathogens reorganize their cell wall components in response to specific plant-derived compounds, which these pathogens may encounter during infection.

  4. Age-dependent rates of infection of cassava green mites by a fungal pathogen in Brazil.

    Science.gov (United States)

    Elliot, Sam L; Mumford, John D; de Moraes, Gilberto J; Sabelis, Maurice W

    2002-01-01

    Age-specific effects of invertebrate pathogens on their hosts can greatly influence the population dynamics in such interactions. Explanations for such differences are usually sought within differing intrinsic susceptibilities of the host life stages but we present data which indicate that host size, behaviour and life history may be the overriding factors determining age-specific effects of a fungal pathogen, Neozygitesfloridana (Entomophthorales: Neozygitaceae) on spider mites (Mononychellus tanajoa Bondar, Acari: Tetranychidae). Epizootics of N. floridana in spider mites are characterised by much greater relative mortality of adult females compared with other life stages (ca. 99%), despite similar physiological susceptibilities. We present empirical data that demonstrate encounter rates of mites with N. floridana increasing with life stage during an epizootic on cassava in northeastern Brazil. Estimates of the size, walking speeds and patterns, and life history of different life stages (and adult sexes) were used to calculate expected relative encounter rates which were found not to be different from the observed values (although not testable for larvae). This helps explain the different apparent susceptibility of host life stages in the field. Given the low ecological susceptibility of younger life stages to this pathogen, we predict that the interaction time between host and pathogen, determined by climatic conditions, will be critical in determining the degree of host population control in an epizootic. We further hypothesise that such variation in ecological susceptibility to pathogens can generate selection pressures on basic host traits, contributing to the sessile nature of many microarthropods.

  5. The CEK1-mediated mitogen-activated protein kinase pathway in the fungal pathogen Candida albicans

    Directory of Open Access Journals (Sweden)

    Elvira Román

    2013-06-01

    Full Text Available Mitogen-activated protein kinases (MAPK mediated signal transduction pathways are essential for the adaptation of living organisms to environmental changes. In pathogenic fungi, these MAPK cascades govern the response to many types of situations, and are essential for the successful establishment of the fungus within the host. Therefore, they influence virulence and can be considered as promising therapeutic targets. In the opportunistic pathogen Candida albicans, the Cek1-mediated pathway was identified long time ago as an important virulence determinant in certain animal models. We will review here the recent work that reveals the role that this route plays in three important processes for the cell: osmotic adaptation, fungal morphogenesis and cell wall remodeling. We will also show the complementary (and sometimes opposite roles that under specific circumstances the high osmolarity glycerol and CEK1 pathways play in C. albicans biology, especially in the context of the interaction with the mammalian host.

  6. Antimicrobial potential of Ricinus communis leaf extracts in different solvents against pathogenic bacterial and fungal strains

    Institute of Scientific and Technical Information of China (English)

    Rabia Naz; Asghari Bano

    2012-01-01

    Objective: To investigate the in vitro antimicrobial activities of the leaf extract in different solvents viz., methanol, ethanol and water extracts of the selected plant Ricinus communis. Methods:Agar well diffusion method and agar tube dilution method were carried out to perform the antibacterial and antifungal activity of methanol, ethanol and aqueous extracts. Results:Methanol leaf extracts were found to be more active against Gram positive bacteria (Bacillus subtilis: ATCC 6059 and Staphylococcus aureus: ATCC 6538) as well as Gram negative bacteria (Pseudomonas aeruginosa: ATCC 7221 and Klebsiella pneumoniae) than ethanol and aqueous leaf extracts. Antifungal activity of methanol and aqueous leaf extracts were also carried out against selected fungal strains as Aspergillus fumigatus and Aspergillus flavus. Methanolic as well as aqueous leaf extracts of Ricinus communis were effective in inhibiting the fungal growth. Conclusions: The efficient antibacterial and antifungal activity of Ricinus communis from the present investigation revealed that the methanol leaf extracts of the selected plant have significant potential to inhibit the growth of pathogenic bacterial and fungal strains than ethanol and aqueous leaf extracts.

  7. In Vitro Studies of the Activity of Dithiocarbamate Organoruthenium Complexes against Clinically Relevant Fungal Pathogens

    Directory of Open Access Journals (Sweden)

    Claudio L. Donnici

    2014-04-01

    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.

  8. Exploration of Fungal Association From Hard Coral Against Pathogen MDR Staphylococcus haemolyticus

    Science.gov (United States)

    Cristianawati, O.; Radjasa, O. K.; Sabdono, A.; Trianto, A.; Sabdaningsih, A.; Sibero, M. T.; Nuryadi, H.

    2017-02-01

    Staphylococcus haemolyticus are opportunistic bacteria and as the second leading cause of nosocomial infections. It is a disease causing septicemia, peritonitis, otitis, and urinary tract infections and infections of the eye. It also a phenotype resistant to multiple antibiotics commercial. There is now an urgency to find an alternative antibiotics to combat this bacteria. It has been widely reported that many bioactive marine natural products from marine invertebrate have striking similarities to metabolites of their associated microorganisms including fungi. Hard coral associated microorganisms are among of the most interesting and promising marine natural product sources, which produce with various biological activities. The proposed work focused on the discovery of bioactive compounds and also estimated the phylogenetic diversity from fungal association of hard coral against pathogen MDR Staphylococcus haemolyticus. A total of 32 fungal association, FHP 7 which were isolated from Favia sp. capable of inhibiting the growth MDR. Molecular identification based on 18S rRNA gene sequences revealed that the active fungal association belonged 100% to the members from one of the genera Trichoderma longibrachiatum. Accession Number LC185084.1.

  9. Antimicrobial potential of Ricinus communis leaf extracts in different solvents against pathogenic bacterial and fungal strains.

    Science.gov (United States)

    Naz, Rabia; Bano, Asghari

    2012-12-01

    To investigate the in vitro antimicrobial activities of the leaf extract in different solvents viz., methanol, ethanol and water extracts of the selected plant Ricinus communis. Agar well diffusion method and agar tube dilution method were carried out to perform the antibacterial and antifungal activity of methanol, ethanol and aqueous extracts. Methanol leaf extracts were found to be more active against Gram positive bacteria (Bacillus subtilis: ATCC 6059 and Staphylococcus aureus: ATCC 6538) as well as Gram negative bacteria (Pseudomonas aeruginosa: ATCC 7221 and Klebsiella pneumoniae) than ethanol and aqueous leaf extracts. Antifungal activity of methanol and aqueous leaf extracts were also carried out against selected fungal strains as Aspergillus fumigatus and Aspergillus flavus. Methanolic as well as aqueous leaf extracts of Ricinus communis were effective in inhibiting the fungal growth. The efficient antibacterial and antifungal activity of Ricinus communis from the present investigation revealed that the methanol leaf extracts of the selected plant have significant potential to inhibit the growth of pathogenic bacterial and fungal strains than ethanol and aqueous leaf extracts.

  10. Caterpillars and fungal pathogens: two co-occurring parasites of an ant-plant mutualism.

    Directory of Open Access Journals (Sweden)

    Olivier Roux

    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.

  11. Fungal-specific transcription factor AbPf2 activates pathogenicity in Alternaria brassicicola

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Yangrae; Ohm, Robin A.; Grigoriev, Igor V.; Srivastava, Akhil

    2012-12-03

    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.

  12. Characterization of Fungal Pathogens Associated with White Pine Needle Damage (WPND in Northeastern North America

    Directory of Open Access Journals (Sweden)

    Kirk Broders

    2015-11-01

    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.

  13. Climate change triggers effects of fungal pathogens and insect herbivores on litter decomposition

    Science.gov (United States)

    Butenschoen, Olaf; Scheu, Stefan

    2014-10-01

    Increasing infestation by insect herbivores and pathogenic fungi in response to climate change will inevitably impact the amount and quality of leaf litter inputs into the soil. However, little is known on the interactive effect of infestation severity and climate change on litter decomposition, and no such study has been published for deciduous forests in Central Europe. We assessed changes in initial chemical quality of beech (Fagus sylvatica L.) and maple litter (Acer platanoides L.) in response to infestation by the gall midge Mikiola fagi Hart. and the pathogenic fungus Sawadaea tulasnei Fuckel, respectively, and investigated interactive effects of infestation severity, changes in temperature and soil moisture on carbon mineralization in a short-term laboratory study. We found that infestation by the gall midge M. fagi and the pathogenic fungus S. tulasnei significantly changed the chemical quality of beech and maple litter. Changes in element concentrations were generally positive and more pronounced, and if negative less pronounced for maple than beech litter most likely due to high quality fungal tissue remaining on litter after abscission. More importantly, alterations in litter chemical quality did not translate to distinct patterns of carbon mineralization at ambient conditions, but even low amounts of infested litter accelerated carbon mineralization at moderately increased soil moisture and in particular at higher temperature. Our results indicate that insect herbivores and fungal pathogens can markedly alter initial litter chemical quality, but that afterlife effects on carbon mineralization depend on soil moisture and temperature, suggesting that increased infestation severity under projected climate change potentially increases soil carbon release in deciduous forests in Central Europe.

  14. Oxidative stress response to menadione and cumene hydroperoxide in the opportunistic fungal pathogen Candida glabrata

    Directory of Open Access Journals (Sweden)

    Mayra Cuéllar-Cruz

    2009-07-01

    Full Text Available Candida glabrata is an opportunistic fungal pathogen that can cause severe invasive infections and can evade phagocytic cell clearance. We are interested in understanding the virulence of this fungal pathogen, in particular its oxidative stress response. Here we investigated C. glabrata, Saccharomyces cerevisiae and Candida albicans responses to two different oxidants: menadione and cumene hydroperoxide (CHP. In log-phase, in the presence of menadione, C. glabrata requires Cta1p (catalase, while in a stationary phase (SP, Cta1p is dispensable. In addition, C. glabrata is less resistant to menadione than C. albicans in SP. The S. cerevisiae laboratory reference strain is less resistant to menadione than C. glabrata and C. albicans; however S. cerevisiaeclinical isolates (CIs are more resistant than the lab reference strain. Furthermore, S. cerevisiae CIs showed an increased catalase activity. Interestingly, in SP C. glabrata and S. cerevisiae are more resistant to CHP than C. albicans and Cta1p plays no apparent role in detoxifying this oxidant.

  15. Oxidative stress response to menadione and cumene hydroperoxide in the opportunistic fungal pathogen Candida glabrata.

    Science.gov (United States)

    Cuéllar-Cruz, Mayra; Castaño, Irene; Arroyo-Helguera, Omar; De Las Peñas, Alejandro

    2009-07-01

    Candida glabrata is an opportunistic fungal pathogen that can cause severe invasive infections and can evade phagocytic cell clearance. We are interested in understanding the virulence of this fungal pathogen, in particular its oxidative stress response. Here we investigated C. glabrata, Saccharomyces cerevisiae and Candida albicans responses to two different oxidants: menadione and cumene hydroperoxide (CHP). In log-phase, in the presence of menadione, C. glabrata requires Cta1p (catalase), while in a stationary phase (SP), Cta1p is dispensable. In addition, C. glabrata is less resistant to menadione than C. albicans in SP. The S. cerevisiae laboratory reference strain is less resistant to menadione than C. glabrata and C. albicans; however S. cerevisiaeclinical isolates (CIs) are more resistant than the lab reference strain. Furthermore, S. cerevisiae CIs showed an increased catalase activity. Interestingly, in SP C. glabrata and S. cerevisiae are more resistant to CHP than C. albicans and Cta1p plays no apparent role in detoxifying this oxidant.

  16. Constitutively activated barley ROPs modulate epidermal cell size, defense reactions and interactions with fungal leaf pathogens.

    Science.gov (United States)

    Pathuri, Indira Priyadarshini; Zellerhoff, Nina; Schaffrath, Ulrich; Hensel, Götz; Kumlehn, Jochen; Kogel, Karl-Heinz; Eichmann, Ruth; Hückelhoven, Ralph

    2008-12-01

    RHO-like monomeric G-proteins of plants (ROPs, also called RACs), are involved in plant development and interaction with the environment. The barley (Hordeum vulgare) ROP protein HvRACB has been shown to be required for entry of the biotrophic powdery mildew fungus Blumeria graminis f.sp. hordei (Bgh) into living host cells. To get a deeper insight into evolutionarily conserved functions of ROPs in cell polarity and pathogen responses, we stably expressed constitutively activated (CA) mutant variants of different barley ROPs (HvRACB, HvRAC1, HvRAC3) in barley. CA HvROPs induced epidermal cell expansion and/or abolished polarity in tip growing root hairs. All three CA HvROPs enhanced susceptibility of barley to penetration by Bgh whereas only CA HvRAC1 supported whole cell H(2)O(2) production in non-penetrated cells. Despite increasing penetration by Bgh, CA HvRAC1 promoted callose deposition at sites of fungal attack and resistance to penetration by Magnaporthe oryzae. The data show an involvement of ROPs in polar growth processes of the monocot barley and in responses to fungal pathogens with different life style.

  17. Targeted Gene Replacement in Fungal Pathogens via Agrobacterium tumefaciens- Mediated Transformation

    DEFF Research Database (Denmark)

    Frandsen, Rasmus John Normand; Frandsen, Mette; Giese, Nanna Henriette

    2012-01-01

    Genome sequence data on fungal pathogens provide the opportunity to carry out a reverse genetics approach to uncover gene function. Efficient methods for targeted genome modifications such as knockout and in locus over-expression are in high demand. Here we describe two efficient single-step clon......Genome sequence data on fungal pathogens provide the opportunity to carry out a reverse genetics approach to uncover gene function. Efficient methods for targeted genome modifications such as knockout and in locus over-expression are in high demand. Here we describe two efficient single......-step cloning strategies for construction of vectors for Agrobacterium tumefaciens-mediated transformation (ATMT). Targeted genome modifications require integration by a homologous double crossover event, which is achieved by placing target sequences on either side of a selection marker gene in the vector....... Protocols are given for two single-step vector construction techniques. The In-Fusion cloning technique is independent of compatible restriction enzyme sites in the vector and the fragment to be cloned. The method can be directly applied to any vector of choice and it is possible to carry out four fragment...

  18. Multicenter Outbreak of Infections by Saprochaete clavata, an Unrecognized Opportunistic Fungal Pathogen

    Science.gov (United States)

    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

    2014-01-01

    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

  19. Emergence of novel fungal pathogens by ecological speciation: importance of the reduced viability of immigrants.

    Science.gov (United States)

    Gladieux, Pierre; Guérin, Fabien; Giraud, Tatiana; Caffier, Valérie; Lemaire, Christophe; Parisi, Luciana; Didelot, Frédérique; LE Cam, Bruno

    2011-11-01

    Expanding global trade and the domestication of ecosystems have greatly accelerated the rate of emerging infectious fungal diseases, and host-shift speciation appears to be a major route for disease emergence. There is therefore an increased interest in identifying the factors that drive the evolution of reproductive isolation between populations adapting to different hosts. Here, we used genetic markers and cross-inoculations to assess the level of gene flow and investigate barriers responsible for reproductive isolation between two sympatric populations of Venturia inaequalis, the fungal pathogen causing apple scab disease, one of the fungal populations causing a recent emerging disease on resistant varieties. Our results showed the maintenance over several years of strong and stable differentiation between the two populations in the same orchards, suggesting ongoing ecological divergence following a host shift. We identified strong selection against immigrants (i.e. host specificity) from different host varieties as the strongest and likely most efficient barrier to gene flow between local and emerging populations. Cross-variety disease transmission events were indeed rare in the field and cross-inoculation tests confirmed high host specificity. Because the fungus mates within its host after successful infection and because pathogenicity-related loci prevent infection of nonhost trees, adaptation to specific hosts may alone maintain both genetic differentiation between and adaptive allelic combinations within sympatric populations parasitizing different apple varieties, thus acting as a 'magic trait'. Additional intrinsic and extrinsic postzygotic barriers might complete reproductive isolation and explain why the rare migrants and F1 hybrids detected do not lead to pervasive gene flow across years. © 2011 Blackwell Publishing Ltd.

  20. Local adaptation and evolutionary potential along a temperature gradient in the fungal pathogen Rhynchosporium commune

    Science.gov (United States)

    Stefansson, Tryggvi S; McDonald, Bruce A; Willi, Yvonne

    2013-01-01

    To predict the response of plant pathogens to climate warming, data are needed on current thermal adaptation, the pathogen's evolutionary potential, and the link between them. We conducted a common garden experiment using isolates of the fungal pathogen Rhynchosporium commune from nine barley populations representing climatically diverse locations. Clonal replicates of 126 genetically distinct isolates were assessed for their growth rate at 12°C, 18°C, and 22°C. Populations originating from climates with higher monthly temperature variation had higher growth rate at all three temperatures compared with populations from climates with less temperature fluctuation. Population differentiation in growth rate (QST) was significantly higher at 22°C than population differentiation for neutral microsatellite loci (GST), consistent with local adaptation for growth at higher temperatures. At 18°C, we found evidence for stabilizing selection for growth rate as QST was significantly lower than GST. Heritability of growth rate under the three temperatures was substantial in all populations (0.58–0.76). Genetic variation was lower in populations with higher growth rate at the three temperatures and evolvability increased under heat stress in seven of nine populations. Our findings imply that the distribution of this pathogen is unlikely to be genetically limited under climate warming, due to its high genetic variation and plasticity for thermal tolerance. PMID:23745143

  1. Dissecting the molecular interactions between wheat and the fungal pathogen Zymoseptoria tritici

    Directory of Open Access Journals (Sweden)

    Graeme James Kettles

    2016-04-01

    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.

  2. Ecological implications of anti-pathogen effects of tropical fungal endophytes and mycorrhizae.

    Science.gov (United States)

    Herre, Edward Allen; Mejía, Luis C; Kyllo, Damond A; Rojas, Enith; Maynard, Zuleyka; Butler, Andre; Van Bael, Sunshine A

    2007-03-01

    We discuss studies of foliar endophytic fungi (FEF) and arbuscular mycorrhizal fungi (AMF) associated with Theobroma cacao in Panama. Direct, experimentally controlled comparisons of endophyte free (E-) and endophyte containing (E+) plant tissues in T. cacao show that foliar endophytes (FEF) that commonly occur in healthy host leaves enhance host defenses against foliar damage due to the pathogen (Phytophthora palmivora). Similarly, root inoculations with commonly occurring AMF also reduce foliar damage due to the same pathogen. These results suggest that endophytic fungi can play a potentially important mutualistic role by augmenting host defensive responses against pathogens. There are two broad classes of potential mechanisms by which endophytes could contribute to host protection: (1) inducing or increasing the expression of intrinsic host defense mechanisms and (2) providing additional sources of defense, extrinsic to those of the host (e.g., endophyte-based chemical antibiosis). The degree to which either of these mechanisms predominates holds distinct consequences for the evolutionary ecology of host-endophyte-pathogen relationships. More generally, the growing recognition that plants are composed of a mosaic of plant and fungal tissues holds a series of implications for the study of plant defense, physiology, and genetics.

  3. Genome-Wide Host-Pathogen Interaction Unveiled by Transcriptomic Response of Diamondback Moth to Fungal Infection.

    Directory of Open Access Journals (Sweden)

    Zhen-Jian Chu

    Full Text Available Genome-wide insight into insect pest response to the infection of Beauveria bassiana (fungal insect pathogen is critical for genetic improvement of fungal insecticides but has been poorly explored. We constructed three pairs of transcriptomes of Plutella xylostella larvae at 24, 36 and 48 hours post treatment of infection (hptI and of control (hptC for insight into the host-pathogen interaction at genomic level. There were 2143, 3200 and 2967 host genes differentially expressed at 24, 36 and 48 hptI/hptC respectively. These infection-responsive genes (~15% of the host genome were enriched in various immune processes, such as complement and coagulation cascades, protein digestion and absorption, and drug metabolism-cytochrome P450. Fungal penetration into cuticle and host defense reaction began at 24 hptI, followed by most intensive host immune response at 36 hptI and attenuated immunity at 48 hptI. Contrastingly, 44% of fungal genes were differentially expressed in the infection course and enriched in several biological processes, such as antioxidant activity, peroxidase activity and proteolysis. There were 1636 fungal genes co-expressed during 24-48 hptI, including 116 encoding putative secretion proteins. Our results provide novel insights into the insect-pathogen interaction and help to probe molecular mechanisms involved in the fungal infection to the global pest.

  4. Genomic analyses and expression evaluation of thaumatin-like gene family in the cacao fungal pathogen Moniliophthora perniciosa.

    Science.gov (United States)

    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

    2015-10-30

    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.

  5. The effects of microgravity and clinorotation on the interaction of plant cells with fungal pathogen

    Science.gov (United States)

    Nedukha, O.; Kordyum, E.; Leach, J.; Martyn, G.; Ryba-White, M.

    The influence of microgravity and slow horizontal clinorotation (2 rev/min), which partly mimics microgravity, on the interaction of plant cells of soybean roots to Phytophthora sojae and of potato minitubers to Phytophthora infestans was studied during the Space Shuttle Mission STS-87 and during clinorotation. Seedlings of soybean cultivar Williams 82 grown in spaceflight and at 1 g were untreated or inoculated with pathogen P. sojae; minitubers of potato (cv Adreta) grown at horizontal clinorotation and the vertical control also were untreated or inoculated with pathogen P. infestans. The methods of light microscopy, scanning and transmission electron microscopy, confocal microscopy and also cytochemistry for the determination of callose content and peroxydase activity were used in the experiments. Post-landing analysis of the meristem cells of soybean roots infected with P. sojae and post-clinorotation analysis of the parenchyma cells of potato minitubers cells infected with P. infestans showed more destroying symptoms in cells of plant-host, which were more extensive colonized relative to the controls exposed to the pathogen fungus. Infected cells of plants-host were divided in two types: cells of first type were completely destroyed and hyphae of pathogen fungus were into these cells or in intercellular spaces; cells of second type characterized by partly changed ultrastructure and a calcium sites were contained above in mentioned cells. These data suggest that root cells of soybean seedlings grown in microgravity and cells of potato minitubers grown at slow horizontal clinorotation are more susceptible to penetration of a fungal pathogen in comparison with the corresponding controls.

  6. A temperature-responsive network links cell shape and virulence traits in a primary fungal pathogen.

    Directory of Open Access Journals (Sweden)

    Sinem Beyhan

    2013-07-01

    Full Text Available Survival at host temperature is a critical trait for pathogenic microbes of humans. Thermally dimorphic fungal pathogens, including Histoplasma capsulatum, are soil fungi that undergo dramatic changes in cell shape and virulence gene expression in response to host temperature. How these organisms link changes in temperature to both morphologic development and expression of virulence traits is unknown. Here we elucidate a temperature-responsive transcriptional network in H. capsulatum, which switches from a filamentous form in the environment to a pathogenic yeast form at body temperature. The circuit is driven by three highly conserved factors, Ryp1, Ryp2, and Ryp3, that are required for yeast-phase growth at 37°C. Ryp factors belong to distinct families of proteins that control developmental transitions in fungi: Ryp1 is a member of the WOPR family of transcription factors, and Ryp2 and Ryp3 are both members of the Velvet family of proteins whose molecular function is unknown. Here we provide the first evidence that these WOPR and Velvet proteins interact, and that Velvet proteins associate with DNA to drive gene expression. Using genome-wide chromatin immunoprecipitation studies, we determine that Ryp1, Ryp2, and Ryp3 associate with a large common set of genomic loci that includes known virulence genes, indicating that the Ryp factors directly control genes required for pathogenicity in addition to their role in regulating cell morphology. We further dissect the Ryp regulatory circuit by determining that a fourth transcription factor, which we name Ryp4, is required for yeast-phase growth and gene expression, associates with DNA, and displays interdependent regulation with Ryp1, Ryp2, and Ryp3. Finally, we define cis-acting motifs that recruit the Ryp factors to their interwoven network of temperature-responsive target genes. Taken together, our results reveal a positive feedback circuit that directs a broad transcriptional switch between

  7. Nucleic Acid-Based Detection and Identification of Bacterial and Fungal Plant Pathogens - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Kingsley, Mark T.

    2001-03-13

    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.

  8. Using Population and Comparative Genomics to Understand the Genetic Basis of Effector-Driven Fungal Pathogen Evolution

    Science.gov (United States)

    Plissonneau, Clémence; Benevenuto, Juliana; Mohd-Assaad, Norfarhan; Fouché, Simone; Hartmann, Fanny E.; Croll, Daniel

    2017-01-01

    Epidemics caused by fungal plant pathogens pose a major threat to agro-ecosystems and impact global food security. High-throughput sequencing enabled major advances in understanding how pathogens cause disease on crops. Hundreds of fungal genomes are now available and analyzing these genomes highlighted the key role of effector genes in disease. Effectors are small secreted proteins that enhance infection by manipulating host metabolism. Fungal genomes carry 100s of putative effector genes, but the lack of homology among effector genes, even for closely related species, challenges evolutionary and functional analyses. Furthermore, effector genes are often found in rapidly evolving chromosome compartments which are difficult to assemble. We review how population and comparative genomics toolsets can be combined to address these challenges. We highlight studies that associated genome-scale polymorphisms with pathogen lifestyles and adaptation to different environments. We show how genome-wide association studies can be used to identify effectors and other pathogenicity-related genes underlying rapid adaptation. We also discuss how the compartmentalization of fungal genomes into core and accessory regions shapes the evolution of effector genes. We argue that an understanding of genome evolution provides important insight into the trajectory of host-pathogen co-evolution. PMID:28217138

  9. Fungal trunk pathogens associated with wood decay of pistachio trees in Iran

    Directory of Open Access Journals (Sweden)

    Hamid Mohammadi

    2015-06-01

    Full Text Available Over the growing seasons of 2011–2013, various pistachio (Pistacia vera L. cv. Fandoghi, and wild pistachio (P. atlantica Desf. subsp. mutica trees were inspected in Iran to determine the aetiology of trunk diseases with specific reference to species of Phaeoacremonium and Botryosphaeriaceae spp. Samples were collected from branches of trees exhibiting yellowing, defoliation, canker and dieback, as well as wood discoloration in cross sections. Fungal trunk pathogens were identified using morphological and cultural characteristics as well as comparisons of DNA sequence data of the ITS and TEF-1α (for Botryosphaeriaceae species and β-tubulin gene (for Phaeoacremonium species regions. Phaeoacremonium parasiticum was the dominant species followed by Phaeoacremonium aleophilum, Botryosphaeria dothidea, Neofusicoccum parvum, Phaeoacremoniumcinereum, Phaeoacremonium viticola and Dothiorella viticola. Pathogenicity tests were undertaken to determine the role of these species on pistachio under field conditions. Neofusicoccum parvum and Pm. aleophilum caused the longest and smallest lesions respectively. This study represents the first report on the occurrence and pathogenicity of Phaeoacremonium species on P. vera cv. Fandoghi. This also represents the first report of Pleurostomophora sp. on pistachio and Pm. parasiticum and D. viticola on wild pistachio.

  10. Contrasting introduction scenarios among continents in the worldwide invasion of the banana fungal pathogen Mycosphaerella fijiensis.

    Science.gov (United States)

    Robert, S; Ravigne, V; Zapater, M-F; Abadie, C; Carlier, J

    2012-03-01

    Reconstructing and characterizing introduction routes is a key step towards understanding the ecological and evolutionary factors underlying successful invasions and disease emergence. Here, we aimed to decipher scenarios of introduction and stochastic demographic events associated with the global spread of an emerging disease of bananas caused by the destructive fungal pathogen Mycosphaerella fijiensis. We analysed the worldwide population structure of this fungus using 21 microsatellites and 8 sequence-based markers on 735 individuals from 37 countries. Our analyses designated South-East Asia as the source of the global invasion and supported the location of the centre of origin of M. fijiensis within this area. We confirmed the occurrence of bottlenecks upon introduction into other continents followed by widespread founder events within continents. Furthermore, this study suggested contrasting introduction scenarios of the pathogen between the African and American continents. While potential signatures of admixture resulting from multiple introductions were detected in America, all the African samples examined seem to descend from a single successful founder event. In combination with historical information, our study reveals an original and unprecedented global scenario of invasion for this recently emerging disease caused by a wind-dispersed pathogen. © 2012 Blackwell Publishing Ltd.

  11. Pathogenesis and Antifungal Drug Resistance of the Human Fungal Pathogen Candida glabrata

    Directory of Open Access Journals (Sweden)

    Karl Kuchler

    2011-01-01

    Full Text Available Candida glabrata is a major opportunistic human fungal pathogen causing superficial as well as systemic infections in immunocompromised individuals and several other patient cohorts. C. glabrata represents the second most prevalent cause of candidemia and a better understanding of its virulence and drug resistance mechanisms is thus of high medical relevance. In contrast to the diploid dimorphic pathogen C. albicans, whose ability to undergo filamentation is considered a major virulence trait, C. glabrata has a haploid genome and lacks the ability to switch to filamentous growth. A major impediment for the clinical therapy of C. glabrata infections is its high intrinsic resistance to several antifungal drugs, especially azoles. Further, the development of antifungal resistance, particularly during prolonged and prophylactic therapies is diminishing efficacies of therapeutic interventions. In addition, C. glabrata harbors a large repertoire of adhesins involved in the adherence to host epithelia. Interestingly, genome plasticity, phenotypic switching or the remarkable ability to persist and survive inside host immune cells further contribute to the pathogenicity of C. glabrata. In this comprehensive review, we want to emphasize and discuss the mechanisms underlying virulence and drug resistance of C. glabrata, and discuss its ability to escape from the host immune surveillance or persist inside host cells.

  12. Compatibility study of Trichoderma harzianum Rifai and rice fungicides, and effects on three fungal plant pathogens

    Directory of Open Access Journals (Sweden)

    Manuel Francisco Rodríguez Saldaña

    2017-04-01

    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.

  13. Comparative Transcriptome Analysis between the Fungal Plant Pathogens Sclerotinia sclerotiorum and S. trifoliorum Using RNA Sequencing.

    Science.gov (United States)

    Qiu, Dan; Xu, Liangsheng; Vandemark, George; Chen, Weidong

    2016-03-01

    The fungal plant pathogens Sclerotinia sclerotiorum and S. trifoliorum are morphologically similar, but differ considerably in host range. In an effort to elucidate mechanisms of the host range difference, transcriptomes of the 2 species at vegetative growth stage were compared to gain further insight into commonality and uniqueness in gene expression and pathogenic mechanisms of the 2 closely related pathogens. A total of 23133 and 21043 unique transcripts were obtained from S. sclerotiorum and S. trifoliorum, respectively. Approximately 43% of the transcripts were genes with known functions for both species. Among 1411 orthologous contigs, about 10% (147) were more highly (>3-fold) expressed in S. trifoliorum than in S. sclerotiorum, and about 12% (173) of the orthologs were more highly (>3-fold) expressed in S. sclerotiorum than in S. trifoliorum. The expression levels of genes on the supercontig 30 have the highest correlation coefficient value between the 2 species. Twenty-seven contigs were found to be new and unique for S. trifoliorum. Additionally, differences in expressed genes involved in pathogenesis like oxalate biosynthesis and endopolygalacturonases were detected between the 2 species. The analyses of the transcriptomes not only discovered similarities and uniqueness in gene expression between the 2 closely related species, providing additional information for annotation the S. sclerotiorum genome, but also provided foundation for comparing the transcriptomes with host-infecting transcriptomes.

  14. Control of postharvest fungal pathogens by antifungal compounds from Penicillium expansum.

    Science.gov (United States)

    Rouissi, Wafa; Ugolini, Luisa; Martini, Camilla; Lazzeri, Luca; Mari, Marta

    2013-11-01

    The fungicidal effects of secondary metabolites produced by a strain of Penicillium expansum (R82) in culture filtrate and in a double petri dish assay were tested against one isolate each of Botrytis cinerea, Colletotrichum acutatum, and Monilinia laxa and six isolates of P. expansum, revealing inhibitory activity against every pathogen tested. The characterization of volatile organic compounds released by the R82 strain was performed by solid-phase microextraction-gas chromatographic techniques, and several compounds were detected, one of them identified as phenethyl alcohol (PEA). Synthetic PEA, tested in vitro on fungal pathogens, showed strong inhibition at a concentration of 1,230 μg/ml of airspace, and mycelium appeared more sensitive than conidia; nevertheless, at the concentration naturally emitted by the fungus (0.726 ± 0.16 m g/ml), commercial PEA did not show any antifungal activity. Therefore, a combined effect between different volatile organic compounds produced collectively by R82 can be hypothesized. This aspect suggests further investigation into the possibility of exploiting R82 as a nonchemical alternative in the control of some plant pathogenic fungi.

  15. Arabidopsis nonhost resistance gene PSS1 confers immunity against an oomycete and a fungal pathogen but not a bacterial pathogen that cause diseases in soybean

    Directory of Open Access Journals (Sweden)

    Sumit Rishi

    2012-06-01

    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

  16. Regulation of secondary metabolite production in the fungal tomato pathogen Cladosporium fulvum.

    Science.gov (United States)

    Griffiths, Scott; Saccomanno, Benedetta; de Wit, Pierre J G M; Collemare, Jérôme

    2015-11-01

    Cladosporium fulvum is a non-obligate biotrophic fungal tomato pathogen for which fifteen secondary metabolite (SM) gene clusters were previously identified in its genome. However, most of these SM biosynthetic pathways remain cryptic during growth in planta and in different in vitro conditions. The sole SM produced in vitro is the pigment cladofulvin. In this study, we attempted to activate cryptic pathways in order to identify new compounds produced by C. fulvum. For this purpose, we manipulated orthologues of the global regulators VeA, LaeA and HdaA known to regulate SM biosynthesis in other fungal species. In C. fulvum, deleting or over-expressing these regulators yielded no new detectable SMs. Yet, quantification of cladofulvin revealed that CfHdaA is an activator whilst CfVeA and CfLaeA seemed to act as repressors of cladofulvin production. In the wild type strain, cladofulvin biosynthesis was affected by the carbon source, with highest production under carbon limitation and traces only in presence of saccharose. Repression of cladofulvin production by saccharose was dependent on both CfVeA and CfLaeA. Deletion of CfVeA or CfLaeA caused production of sterile mycelia, whilst Δcfhdaa deletion mutants sporulated, suggesting that cladofulvin production is not linked to asexual reproduction. Profiling the transcription of these regulators showed that CfHdaA-mediated regulation of cladofulvin production is independent of both CfVeA and CfLaeA. Our data suggest CfLaeA directly affects cladofulvin production whilst the effect of CfVeA is indirect, suggesting a role for CfLaeA outside of the Velvet complex. In conclusion, our results showed that regulation of SM production in C. fulvum is different from other fungi and indicate that manipulation of global regulators is not a universal tool to discover new fungal natural products.

  17. Synchronicity of pollination and inoculation with Claviceps africana and its effects on pollen-pistil compatibility and seed production in sorghum.

    Science.gov (United States)

    Cisneros-López, Ma Eugenia; Mendoza-Onofre, Leopoldo E; González-Hernández, Víctor A; Zavaleta-Mancera, H Araceli; Mora-Aguilera, Gustavo; Hernández-Martínez, Miguel; Córdova-Téllez, Leobigildo

    2010-04-01

    Sorghum ergot (caused by Claviceps africana) is a disease that affects sorghum seed development and yield. The interaction between pollen tube growth and hyphal development determines whether ovaries will be fertilized or colonized. Thus their respective deposition times on the stigma are critical. The effect of the time interval between pollination and inoculation on stigma receptivity and seed production was measured under field conditions in the male-sterile line A9 at Montecillo, State of México (2240m altitude). Pollination and inoculation treatments, from simultaneous application to 2 and 4h difference, were imposed when all stigmas on the panicle had emerged. Control panicles were either only pollinated or only inoculated. Eighteen hours later, pollen grains that adhered to, and germinated within the stigma, pollen tubes in the style and ovary, and fertilized pistils were counted. Pistils showing some disease expression (germinated spores, mycelium growth, or tissue necrosis) at 18, 48, and 72h were recorded. The number of diseased florets was registered at the dough growth stage, while number of seeds, grain yield and 100-seeds weight was measured at the physiological maturity. The pathogen applied in a water suspension of macro and secondary conidia caused a decrease in stigma receptivity; the greatest decrease (40-60%) occurred when the pollen and the inoculum were deposited almost simultaneously, regardless of which was deposited first. The route of the pollen tube was also the route for fungal infection. On average, treatments first inoculated had 60% more diseased florets and 36% less grain yield, 30% fewer seeds and seed size decreased 8%, than those first pollinated.

  18. Unveiling the structural basis for translational ambiguity tolerance in a human fungal pathogen.

    Science.gov (United States)

    Rocha, Rita; Pereira, Pedro José Barbosa; Santos, Manuel A S; Macedo-Ribeiro, Sandra

    2011-08-23

    In a restricted group of opportunistic fungal pathogens the universal leucine CUG codon is translated both as serine (97%) and leucine (3%), challenging the concept that translational ambiguity has a negative impact in living organisms. To elucidate the molecular mechanisms underlying the in vivo tolerance to a nonconserved genetic code alteration, we have undertaken an extensive structural analysis of proteins containing CUG-encoded residues and solved the crystal structures of the two natural isoforms of Candida albicans seryl-tRNA synthetase. We show that codon reassignment resulted in a nonrandom genome-wide CUG redistribution tailored to minimize protein misfolding events induced by the large-scale leucine-to-serine replacement within the CTG clade. Leucine or serine incorporation at the CUG position in C. albicans seryl-tRNA synthetase induces only local structural changes and, although both isoforms display tRNA serylation activity, the leucine-containing isoform is more active. Similarly, codon ambiguity is predicted to shape the function of C. albicans proteins containing CUG-encoded residues in functionally relevant positions, some of which have a key role in signaling cascades associated with morphological changes and pathogenesis. This study provides a first detailed analysis on natural reassignment of codon identity, unveiling a highly dynamic evolutionary pattern of thousands of fungal CUG codons to confer an optimized balance between protein structural robustness and functional plasticity.

  19. Biocontrol of Phytophthora infestans, Fungal Pathogen of Seedling Damping Off Disease in Economic Plant Nursery

    Directory of Open Access Journals (Sweden)

    B. Loliam

    2012-01-01

    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.

  20. Tissue specific localization of root infection by fungal pathogens: role of root border cells.

    Science.gov (United States)

    Gunawardena, Uvini; Hawes, Martha C

    2002-11-01

    When roots of pea seedlings were inoculated uniformly with spores of Nectria haematocca or other pea pathogenic fungi, more than 90% developed lesions in the region of elongation within 3 days. More mature regions of most roots as well as the tip showed no visible signs of infection. Yet, microscopic observation revealed that 'mantles,' comprised of fungal hyphae intermeshed with populations of border cells, covered the tips of most roots. After physical detachment of the mantle, the underlying tip of most roots was found to be free of infection. Mantle-covered root tips did not respond to invasion of their border cells by activation of known defense genes unless there was invasion of the tip itself, as revealed by the presence of a lesion. Concomitant with the activation of defense genes was the induction of a cell-wall degrading enzyme whose expression is a marker for renewed production of border cells. Mantle formation did not occur in response to nonpathogens. The data are consistent with the hypothesis that border cells serve as a host-specific 'decoy' that protects root meristems by inhibiting fungal infection of the root tip.

  1. Biofertilization and Biocontrol in the fight against soilborne fungal root pathogens in Australian soils

    Science.gov (United States)

    Cooper, Sarah; Agnew, Linda; Pereg, Lily

    2015-04-01

    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.

  2. Chenopodolans A-C: phytotoxic furopyrans produced by Phoma chenopodiicola, a fungal pathogen of Chenopodium album.

    Science.gov (United States)

    Cimmino, Alessio; Andolfi, Anna; Zonno, Maria Chiara; Avolio, Fabiana; Berestetskiy, Alexander; Vurro, Maurizio; Evidente, Antonio

    2013-12-01

    Three tetrasubstituted furopyrans, named chenopodolans A-C, were isolated together with the well known fungal metabolite (-)-(R)-6-hydroxymellein from the liquid culture of Phoma chenopodiicola, a fungal pathogen proposed for the biological control of Chenopodium album, a common worldwide weed of arable crops. The structures of chenopodolans A-C were established by spectroscopic and chemical methods as 2-(3-methoxy-2,6-dimethyl-7aH-furo[2,3-b]pyran-4-yl)-butane-2,3-diol, 1-(3-methoxy-2,6-dimethyl-7aH-furo[2,3-b]pyran-4-yl)ethanol and 3-methoxy-2,6-dimethyl-4-(1-methylpropenyl)-7aH-furo[2,3-b]pyran, respectively. The absolute configuration R to the hydroxylated secondary carbon (C-11) of the side chain at C-4 of chenopodolan A was determined by applying an advanced Mosher's method. Assayed by leaf puncture on host and non-host weeds chenopodolans A and B, and the 11-O-acetylchenopodolan A showed a strong phytotoxicity. These results showed that the nature of the side chain attached to C-4 is an important feature for the phytotoxicity. A weak zootoxic activity was only showed by chenopodolan B.

  3. Structure and mechanism of chitin deacetylase from the fungal pathogen Colletotrichum lindemuthianum.

    Science.gov (United States)

    Blair, David E; Hekmat, Omid; Schüttelkopf, Alexander W; Shrestha, Binesh; Tokuyasu, Ken; Withers, Stephen G; van Aalten, Daan M F

    2006-08-08

    The fungal pathogen Colletotrichum lindemuthianum secretes an endo-chitin de-N-acetylase (ClCDA) to modify exposed hyphal chitin during penetration and infection of plants. Although a significant amount of biochemical data is available on fungal chitin de-N-acetylases, no structural data exist. Here we describe the 1.8 A crystal structure of a ClCDA product complex and the analysis of the reaction mechanism using Hammett linear free energy relationships, subsite probing, and atomic absorption spectroscopy studies. The structural data in combination with biochemical data reveal that ClCDA consists of a single domain encompassing a mononuclear metalloenzyme which employs a conserved His-His-Asp zinc-binding triad closely associated with the conserved catalytic base (aspartic acid) and acid (histidine) to carry out acid/base catalysis. The data presented here indicate that ClCDA possesses a highly conserved substrate-binding groove, with subtle alterations that influence substrate specificity and subsite affinity. Strikingly, the structure also shows that the hexahistidine purification tag appears to form a tight interaction with the active site groove. The enzyme requires occupancy of at least the 0 and +1 subsites by (GlcNAc)(2) for activity and proceeds through a tetrahedral oxyanion intermediate.

  4. Azole fungicides - understanding resistance mechanisms in agricultural fungal pathogens.

    Science.gov (United States)

    Price, Claire L; Parker, Josie E; Warrilow, Andrew G S; Kelly, Diane E; Kelly, Steven L

    2015-08-01

    Plant fungal pathogens can have devastating effects on a wide range of crops, including cereals and fruit (such as wheat and grapes), causing losses in crop yield, which are costly to the agricultural economy and threaten food security. Azole antifungals are the treatment of choice; however, resistance has arisen against these compounds, which could lead to devastating consequences. Therefore, it is important to understand how these fungicides are used and how the resistance arises in order to tackle the problem fully. Here, we give an overview of the problem and discuss the mechanisms that mediate azole resistance in agriculture (point mutations in the CYP51 amino acid sequence, overexpression of the CYP51 enzyme and overexpression of genes encoding efflux pump proteins). © 2015 Society of Chemical Industry.

  5. Development of a Selective Medium for the Fungal Pathogen Cylindrocarpon destructans Using Radicicol

    Directory of Open Access Journals (Sweden)

    Yunhee Kang

    2014-12-01

    Full Text Available The soil-borne ascomycete fungus Cylindrocarpon destructans causes ginseng root rot disease and produces various secondary metabolites such as brefeldin A and radicicol. The slow growth of this fungus compared with other plant pathogenic and saprophytic fungi in soil disturbs isolation of this fungus from soil and infected ginseng. In this study, we developed a selective medium for C. destructans using radicicol produced by this fungus. Supplementing 50 mg/L of radicicol to medium inhibited the mycelia growth of other fungi including Botrytis cinerea, Rhizoctonia solani and Alternaria panax, but did not affect the growth of C. destructans. In addition, conidia germination of other fungal species except for C. destructans was inhibited in submerged culture supplemented with radicicol. This medium provides a very efficient tool for isolating C. destructans and also can be used as an enrichment medium for this fungus.

  6. Agropyrenol and agropyrenal, phytotoxins from Ascochyta agropyrina var. nana, a fungal pathogen of Elitrigia repens.

    Science.gov (United States)

    Andolfi, Anna; Cimmino, Alessio; Vurro, Maurizio; Berestetskiy, Alexander; Troise, Ciro; Zonno, Maria Chiara; Motta, Andrea; Evidente, Antonio

    2012-07-01

    A strain of Ascochyta agropyrina var. nana, a fungal pathogen of the perennial weed Elytrigia repens, produced several toxins in a liquid medium, and its primary toxin, named agropyrenol, was characterized as a substituted salicylaldehyde on the basis of its chemical and spectroscopic properties. Its absolute stereochemistry was determined by Mosher's method. Two other minor metabolites were isolated from the same culture and named agropyrenal and agropyrenone, respectively. They were characterized as a trisubstituted naphthalene carbaldehyde and a pentasubstituted 3H-benzofuranone, respectively, using the same techniques. When assayed on leaves of several weed plants, i.e., Mercurialis annua, Chenopodium album and Setaria viridis, agropyrenol proved to be phytotoxic, causing the appearance of necrotic lesions, agropyrenal was less active, while agropyrenone was inactive. None of the compounds showed antibiotic, fungicidal or zootoxic activity.

  7. Evaluation of two conservation methods of filamentous fungal oil palm pathogens

    Directory of Open Access Journals (Sweden)

    Oscar Eduardo Ladino Rey

    2016-07-01

    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.

  8. Pathogenic Yet Environmentally Friendly? Black Fungal Candidates for Bioremediation of Pollutants

    Science.gov (United States)

    Blasi, Barbara; Poyntner, Caroline; Rudavsky, Tamara; Prenafeta-Boldú, Francesc X.; Hoog, Sybren De; Tafer, Hakim; Sterflinger, Katja

    2016-01-01

    ABSTRACT A collection of 163 strains of black yeast-like fungi from the CBS Fungal Biodiversity Center (Utrecht, The Netherlands), has been screened for the ability to grow on hexadecane, toluene and polychlorinated biphenyl 126 (PCB126) as the sole carbon and energy source. These compounds were chosen as representatives of relevant environmental pollutants. A microtiter plate-based culture assay was set up in order to screen the fungal strains for growth on the selected xenobiotics versus glucose, as a positive control. Growth was observed in 25 strains on at least two of the tested substrates. Confirmation of substrate assimilation was performed by cultivation on closed vials and analysis of the headspace composition with regard to the added volatile substrates and the generated carbon dioxide. Exophiala mesophila (CBS 120910) and Cladophialophora immunda (CBS 110551), both of the order Chaetothyriales and isolated from a patient with chronic sinusitis and a polluted soil sample, respectively, showed the ability to grow on toluene as the sole carbon and energy source. Toluene assimilation has previously been described for C. immunda but this is the first account for E. mesophila. Also, this is the first time that the capacity to grow on alkylbenzenes has been demonstrated for a clinical isolate. Assimilation of toluene could not be demonstrated for the human opportunistic pathogen Pseudoallescheria boydii (CBS 115.59, Microascales), but the results from microtiter plate assays suggest that strains of this species are promising candidates for further studies. The outstanding abilities of black yeast-like fungi to thrive in extreme environments makes them ideal agents for the bioremediation of polluted soils, and for the treatment of contaminated gas streams in biofilters. However, interrelations between hydrocarbonoclastic and potentially pathogenic strains need to be elucidated in order to avoid the possibility of biohazards occurring. PMID:27019541

  9. Predicting invasive fungal pathogens using invasive pest assemblages: testing model predictions in a virtual world.

    Directory of Open Access Journals (Sweden)

    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.

  10. Predicting Invasive Fungal Pathogens Using Invasive Pest Assemblages: Testing Model Predictions in a Virtual World

    Science.gov (United States)

    Paini, Dean R.; Bianchi, Felix J. J. A.; Northfield, Tobin D.; De Barro, Paul J.

    2011-01-01

    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. PMID:22016773

  11. The Alternaria genomes database: a comprehensive resource for a fungal genus comprised of saprophytes, plant pathogens, and allergenic species.

    Science.gov (United States)

    Dang, Ha X; Pryor, Barry; Peever, Tobin; Lawrence, Christopher B

    2015-03-25

    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

  12. Genomic analysis of the necrotrophic fungal pathogens Sclerotinia sclerotiorum and Botrytis cinerea.

    Directory of Open Access Journals (Sweden)

    Joelle Amselem

    2011-08-01

    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

  13. Defence reactions of plants to fungal pathogens: principles and perspectives, using powdery mildew on cereals as an example

    Science.gov (United States)

    Heitefuss, Rudolf

    2001-06-01

    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.

  14. Identifying differentially expressed genes in leaves of Glycine tomentella in the presence of the fungal pathogen Phakopsora pachyrhizi

    Science.gov (United States)

    Transcription profiles of Glycine tomentella genotypes having different responses to soybean rust, caused by the fungal pathogen Phakopsora pachyrhizi, were compared using suppression subtractive hybridization (SSH). Four cDNA libraries were constructed from infected and non-infected leaves of resis...

  15. Sex-specific costs of resistance to the fungal pathogen Ustilago violacea (Microbotryum violaceum) in Silene alba

    NARCIS (Netherlands)

    Biere, A.; Antonovics, J.

    1996-01-01

    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 pres

  16. Isolation from the Sorghum bicolor Mycorrhizosphere of a Bacterium Compatible with Arbuscular Mycorrhiza Development and Antagonistic towards Soilborne Fungal Pathogens

    Science.gov (United States)

    Budi, S. W.; van Tuinen, D.; Martinotti, G.; Gianinazzi, S.

    1999-01-01

    A gram-positive bacterium with antagonistic activity towards soilborne fungal pathogens has been isolated from the mycorrhizosphere of Sorghum bicolor inoculated with Glomus mosseae. It has been identified as Paenibacillus sp. strain B2 based on its analytical profile index and on 16S ribosomal DNA analysis. Besides having antagonistic activity, this bacterium stimulates mycorrhization. PMID:10543835

  17. New insights into the in vitro development and virulence of Culicinomyces spp. as fungal pathogens of Aedes aegypti

    Science.gov (United States)

    Culicinomyces spp. (Hypocreales: Cordycipitaceae) are facultative fungal pathogens affecting the larval stages from a range of mosquito species and are especially notable in their ability to infect hosts through the digestive tract after conidial ingestion. While Culicinomyces spp. were studied main...

  18. The Mystery of Spot Blotch Disease Caused by the Fungal Pathogen Bipolaris sorokiniana on Barley (Hordeum vulgare L)

    DEFF Research Database (Denmark)

    Gjendal, Nele

    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 was investig...

  19. Interactions between fungal plant pathogens on leaves. Especially simultaneous development of Rhynchosporium secalis and Drechslera teres on barley

    DEFF Research Database (Denmark)

    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 ...

  20. The Mystery of Spot Blotch Disease Caused by the Fungal Pathogen Bipolaris sorokiniana on Barley (Hordeum vulgare L)

    DEFF Research Database (Denmark)

    Gjendal, Nele

    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 was investig...

  1. Emerging trends in molecular interactions between plants and the broad host range fungal pathogens Botrytis cinerea and Sclerotinia sclerotiorum

    Directory of Open Access Journals (Sweden)

    Malick eMbengue

    2016-03-01

    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.

  2. Efeito de fungicidas na germinação in vitro de conídios de Claviceps africana Fungicides effect on conidia germination of Claviceps africana in vitro

    Directory of Open Access Journals (Sweden)

    Sônia Regina Nogueira

    2002-10-01

    Full Text Available A cultura do sorgo não enfrentava problemas sérios de doenças nas condições de cultivo no Brasil, até o ano de 1995, quando se registrou a ocorrência da doença-açucarada, causada por Claviceps africana, que afeta as panículas e reduz a quantidade e a qualidade dos grãos; os conídios constituem a principal fonte de inóculo fúngico. Este trabalho teve como objetivo estudar o efeito dos fungicidas tebuconazole, propiconazole, triadimenol, triadimefon, flutriafol e mancozeb na inibição in vitro da germinação dos conídios. Os fungicidas mancozeb, triadimenol e propiconazole foram os mais eficientes na inibição da germinação dos conídios.The sorghum crop did not face serious problems with diseases in Brazil, until occurrence of sugary disease (sorghum ergot, caused by Claviceps africana, was recorded in 1995 in Brazilian sorghum fields. The pathogen infects panicles reducing the quantity and quality of the produced grains. Conidia are the main fungus inoculum. This work aimed to study the potential of fungicides tebuconazole, propiconazole, triadimenol, triadimefon, flutriafol and mancozeb in inhibiting conidia germination in vitro. The fungicides mancozeb, triadimenol and propiconazole were the most effective to inhibit the in vitro germination.

  3. Sfp-type 4'-phosphopantetheinyl transferase is indispensable for fungal pathogenicity.

    Science.gov (United States)

    Horbach, Ralf; Graf, Alexander; Weihmann, Fabian; Antelo, Luis; Mathea, Sebastian; Liermann, Johannes C; Opatz, Till; Thines, Eckhard; Aguirre, Jesús; Deising, Holger B

    2009-10-01

    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.

  4. Modelling the regulation of thermal adaptation in Candida albicans, a major fungal pathogen of humans.

    Science.gov (United States)

    Leach, Michelle D; Tyc, Katarzyna M; Brown, Alistair J P; Klipp, Edda

    2012-01-01

    Eukaryotic cells have evolved mechanisms to sense and adapt to dynamic environmental changes. Adaptation to thermal insults, in particular, is essential for their survival. The major fungal pathogen of humans, Candida albicans, is obligately associated with warm-blooded animals and hence occupies thermally buffered niches. Yet during its evolution in the host it has retained a bona fide heat shock response whilst other stress responses have diverged significantly. Furthermore the heat shock response is essential for the virulence of C. albicans. With a view to understanding the relevance of this response to infection we have explored the dynamic regulation of thermal adaptation using an integrative systems biology approach. Our mathematical model of thermal regulation, which has been validated experimentally in C. albicans, describes the dynamic autoregulation of the heat shock transcription factor Hsf1 and the essential chaperone protein Hsp90. We have used this model to show that the thermal adaptation system displays perfect adaptation, that it retains a transient molecular memory, and that Hsf1 is activated during thermal transitions that mimic fever. In addition to providing explanations for the evolutionary conservation of the heat shock response in this pathogen and the relevant of this response to infection, our model provides a platform for the analysis of thermal adaptation in other eukaryotic cells.

  5. Modelling the regulation of thermal adaptation in Candida albicans, a major fungal pathogen of humans.

    Directory of Open Access Journals (Sweden)

    Michelle D Leach

    Full Text Available Eukaryotic cells have evolved mechanisms to sense and adapt to dynamic environmental changes. Adaptation to thermal insults, in particular, is essential for their survival. The major fungal pathogen of humans, Candida albicans, is obligately associated with warm-blooded animals and hence occupies thermally buffered niches. Yet during its evolution in the host it has retained a bona fide heat shock response whilst other stress responses have diverged significantly. Furthermore the heat shock response is essential for the virulence of C. albicans. With a view to understanding the relevance of this response to infection we have explored the dynamic regulation of thermal adaptation using an integrative systems biology approach. Our mathematical model of thermal regulation, which has been validated experimentally in C. albicans, describes the dynamic autoregulation of the heat shock transcription factor Hsf1 and the essential chaperone protein Hsp90. We have used this model to show that the thermal adaptation system displays perfect adaptation, that it retains a transient molecular memory, and that Hsf1 is activated during thermal transitions that mimic fever. In addition to providing explanations for the evolutionary conservation of the heat shock response in this pathogen and the relevant of this response to infection, our model provides a platform for the analysis of thermal adaptation in other eukaryotic cells.

  6. Identification of Biocontrol Agents to Control the Fungal Pathogen, Geomyces destructans, in Bats

    Science.gov (United States)

    Braunstein, S.; Cheng, T.

    2013-12-01

    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

  7. Experimental verification and molecular basis of active immunization against fungal pathogens in termites.

    Science.gov (United States)

    Liu, Long; Li, Ganghua; Sun, Pengdong; Lei, Chaoliang; Huang, Qiuying

    2015-10-13

    Termites are constantly exposed to many pathogens when they nest and forage in the field, so they employ various immune strategies to defend against pathogenic infections. Here, we demonstrate that the subterranean termite Reticulitermes chinensis employs active immunization to defend against the entomopathogen Metarhizium anisopliae. Our results showed that allogrooming frequency increased significantly between fungus-treated termites and their nestmates. Through active social contact, previously healthy nestmates only received small numbers of conidia from fungus-treated individuals. These nestmates experienced low-level fungal infections, resulting in low mortality and apparently improved antifungal defences. Moreover, infected nestmates promoted the activity of two antioxidant enzymes (SOD and CAT) and upregulated the expression of three immune genes (phenoloxidase, transferrin, and termicin). We found 20 differentially expressed proteins associated with active immunization in R. chinensis through iTRAQ proteomics, including 12 stress response proteins, six immune signalling proteins, and two immune effector molecules. Subsequently, two significantly upregulated (60S ribosomal protein L23 and isocitrate dehydrogenase) and three significantly downregulated (glutathione S-transferase D1, cuticle protein 19, and ubiquitin conjugating enzyme) candidate immune proteins were validated by MRM assays. These findings suggest that active immunization in termites may be regulated by different immune proteins.

  8. Early Lotus japonicus root transcriptomic responses to symbiotic and pathogenic fungal exudates

    Directory of Open Access Journals (Sweden)

    Marco eGiovannetti

    2015-06-01

    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.

  9. Complete genome sequence of Bacillus velezensis M75, a biocontrol agent against fungal plant pathogens, isolated from cotton waste.

    Science.gov (United States)

    Kim, Sang Yoon; Lee, Sang Yeob; Weon, Hang-Yeon; Sang, Mee Kyung; Song, Jaekyeong

    2017-01-10

    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.

  10. Antagonistic changes in sensitivity to antifungal drugs by mutations of an important ABC transporter gene in a fungal pathogen.

    Directory of Open Access Journals (Sweden)

    Wenjun Guan

    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.

  11. Targeting Iron Acquisition Blocks Infection with the Fungal Pathogens Aspergillus fumigatus and Fusarium oxysporum

    Science.gov (United States)

    Leal, Sixto M.; Roy, Sanhita; Vareechon, Chairut; Carrion, Steven deJesus; Clark, Heather; Lopez-Berges, Manuel S.; diPietro, Antonio; Schrettl, Marcus; Beckmann, Nicola; Redl, Bernhard; Haas, Hubertus; Pearlman, Eric

    2013-01-01

    Filamentous fungi are an important cause of pulmonary and systemic morbidity and mortality, and also cause corneal blindness and visual impairment worldwide. Utilizing in vitro neutrophil killing assays and a model of fungal infection of the cornea, we demonstrated that Dectin-1 dependent IL-6 production regulates expression of iron chelators, heme and siderophore binding proteins and hepcidin in infected mice. In addition, we show that human neutrophils synthesize lipocalin-1, which sequesters fungal siderophores, and that topical lipocalin-1 or lactoferrin restricts fungal growth in vivo. Conversely, we show that exogenous iron or the xenosiderophore deferroxamine enhances fungal growth in infected mice. By examining mutant Aspergillus and Fusarium strains, we found that fungal transcriptional responses to low iron levels and extracellular siderophores are essential for fungal growth during infection. Further, we showed that targeting fungal iron acquisition or siderophore biosynthesis by topical application of iron chelators or statins reduces fungal growth in the cornea by 60% and that dual therapy with the iron chelator deferiprone and statins further restricts fungal growth by 75%. Together, these studies identify specific host iron-chelating and fungal iron-acquisition mediators that regulate fungal growth, and demonstrate that therapeutic inhibition of fungal iron acquisition can be utilized to treat topical fungal infections. PMID:23853581

  12. Gene discovery for the bark beetle-vectored fungal tree pathogen Grosmannia clavigera

    Directory of Open Access Journals (Sweden)

    Robertson Gordon

    2010-10-01

    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.

  13. Crossover fungal pathogens: the biology and pathogenesis of fungi capable of crossing kingdoms to infect plants and humans.

    Science.gov (United States)

    Gauthier, Gregory M; Keller, Nancy P

    2013-12-01

    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.

  14. Claviceps purpurea expressing polygalacturonases escaping PGIP inhibition fully infects PvPGIP2 wheat transgenic plants but its infection is delayed in wheat transgenic plants with increased level of pectin methyl esterification.

    Science.gov (United States)

    Volpi, Chiara; Raiola, Alessandro; Janni, Michela; Gordon, Anna; O'Sullivan, Donal M; Favaron, Francesco; D'Ovidio, Renato

    2013-12-01

    Claviceps purpurea is a biotrophic fungal pathogen of grasses causing the ergot disease. The infection process of C. purpurea on rye flowers is accompanied by pectin degradation and polygalacturonase (PG) activity represents a pathogenicity factor. Wheat is also infected by C. purpurea and we tested whether the presence of polygalacturonase inhibiting protein (PGIP) can affect pathogen infection and ergot disease development. Wheat transgenic plants expressing the bean PvPGIP2 did not show a clear reduction of disease symptoms when infected with C. purpurea. To ascertain the possible cause underlying this lack of improved resistance of PvPGIP2 plants, we expressed both polygalacturonases present in the C. purpurea genome, cppg1 and cppg2 in Pichia pastoris. In vitro assays using the heterologous expressed PGs and PvPGIP2 showed that neither PG is inhibited by this inhibitor. To further investigate the role of PG in the C. purpurea/wheat system, we demonstrated that the activity of both PGs of C. purpurea is reduced on highly methyl esterified pectin. Finally, we showed that this reduction in PG activity is relevant in planta, by inoculating with C. purpurea transgenic wheat plants overexpressing a pectin methyl esterase inhibitor (PMEI) and showing a high degree of pectin methyl esterification. We observed reduced disease symptoms in the transgenic line compared with null controls. Together, these results highlight the importance of pectin degradation for ergot disease development in wheat and sustain the notion that inhibition of pectin degradation may represent a possible route to control of ergot in cereals.

  15. The general transcriptional repressor Tup1 is required for dimorphism and virulence in a fungal plant pathogen.

    Directory of Open Access Journals (Sweden)

    Alberto Elías-Villalobos

    2011-09-01

    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.

  16. Characterization of the Complete Uric Acid Degradation Pathway in the Fungal Pathogen Cryptococcus neoformans

    Science.gov (United States)

    Lee, I. Russel; Yang, Liting; Sebetso, Gaseene; Allen, Rebecca; Doan, Thi H. N.; Blundell, Ross; Lui, Edmund Y. L.; Morrow, Carl A.; Fraser, James A.

    2013-01-01

    Degradation of purines to uric acid is generally conserved among organisms, however, the end product of uric acid degradation varies from species to species depending on the presence of active catabolic enzymes. In humans, most higher primates and birds, the urate oxidase gene is non-functional and hence uric acid is not further broken down. Uric acid in human blood plasma serves as an antioxidant and an immune enhancer; conversely, excessive amounts cause the common affliction gout. In contrast, uric acid is completely degraded to ammonia in most fungi. Currently, relatively little is known about uric acid catabolism in the fungal pathogen Cryptococcus neoformans even though this yeast is commonly isolated from uric acid-rich pigeon guano. In addition, uric acid utilization enhances the production of the cryptococcal virulence factors capsule and urease, and may potentially modulate the host immune response during infection. Based on these important observations, we employed both Agrobacterium-mediated insertional mutagenesis and bioinformatics to predict all the uric acid catabolic enzyme-encoding genes in the H99 genome. The candidate C. neoformans uric acid catabolic genes identified were named: URO1 (urate oxidase), URO2 (HIU hydrolase), URO3 (OHCU decarboxylase), DAL1 (allantoinase), DAL2,3,3 (allantoicase-ureidoglycolate hydrolase fusion protein), and URE1 (urease). All six ORFs were then deleted via homologous recombination; assaying of the deletion mutants' ability to assimilate uric acid and its pathway intermediates as the sole nitrogen source validated their enzymatic functions. While Uro1, Uro2, Uro3, Dal1 and Dal2,3,3 were demonstrated to be dispensable for virulence, the significance of using a modified animal model system of cryptococcosis for improved mimicking of human pathogenicity is discussed. PMID:23667704

  17. Comparative Phenotypic Analysis of the Major Fungal Pathogens Candida parapsilosis and Candida albicans

    Science.gov (United States)

    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

    2014-01-01

    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

  18. Comparative phenotypic analysis of the major fungal pathogens Candida parapsilosis and Candida albicans.

    Science.gov (United States)

    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

    2014-09-01

    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.

  19. Staurosporine Induces Filamentation in the Human Fungal Pathogen Candida albicans via Signaling through Cyr1 and Protein Kinase A

    Science.gov (United States)

    Xie, Jinglin L.; O’Meara, Teresa R.; Polvi, Elizabeth J.; Robbins, Nicole

    2017-01-01

    ABSTRACT Protein kinases are key regulators of signal transduction pathways that participate in diverse cellular processes. In fungal pathogens, kinases regulate signaling pathways that govern drug resistance, stress adaptation, and pathogenesis. The impact of kinases on the fungal regulatory circuitry has recently garnered considerable attention in the opportunistic fungal pathogen Candida albicans, which is a leading cause of human morbidity and mortality. Complex regulatory circuitry governs the C. albicans morphogenetic transition between yeast and filamentous growth, which is a key virulence trait. Here, we report that staurosporine, a promiscuous kinase inhibitor that abrogates fungal drug resistance, also influences C. albicans morphogenesis by inducing filamentation in the absence of any other inducing cue. We further establish that staurosporine exerts its effect via the adenylyl cyclase Cyr1 and the cyclic AMP (cAMP)-dependent protein kinase A (PKA). Strikingly, filamentation induced by staurosporine does not require the known upstream regulators of Cyr1, Ras1 or Pkc1, or effectors downstream of PKA, including Efg1. We further demonstrate that Cyr1 is capable of activating PKA to enable filamentation in response to staurosporine through a mechanism that does not require degradation of the transcriptional repressor Nrg1. We establish that staurosporine-induced filamentation is accompanied by a defect in septin ring formation, implicating cell cycle kinases as potential staurosporine targets underpinning this cellular response. Thus, we establish staurosporine as a chemical probe to elucidate the architecture of cellular signaling governing fungal morphogenesis and highlight the existence of novel circuitry through which the Cyr1 and PKA govern a key virulence trait. IMPORTANCE The impact of fungal pathogens on human health is devastating. One of the most pervasive fungal pathogens is Candida albicans, which kills ~40% of people suffering from bloodstream

  20. Structure-Activity Relationship of α Mating Pheromone from the Fungal Pathogen Fusarium oxysporum.

    Science.gov (United States)

    Vitale, Stefania; Partida-Hanon, Angélica; Serrano, Soraya; Martínez-Del-Pozo, Álvaro; Di Pietro, Antonio; Turrà, David; Bruix, Marta

    2017-03-03

    During sexual development ascomycete fungi produce two types of peptide pheromones termed a and α. The α pheromone from the budding yeast Saccharomyces cerevisiae, a 13-residue peptide that elicits cell cycle arrest and chemotropic growth, has served as paradigm for the interaction of small peptides with their cognate G protein-coupled receptors. However, no structural information is currently available for α pheromones from filamentous ascomycetes, which are significantly shorter and share almost no sequence similarity with the S. cerevisiae homolog. High resolution structure of synthetic α-pheromone from the plant pathogenic ascomycete Fusarium oxysporum revealed the presence of a central β-turn resembling that of its yeast counterpart. Disruption of the-fold by d-alanine substitution of the conserved central Gly(6)-Gln(7) residues or by random sequence scrambling demonstrated a crucial role for this structural determinant in chemoattractant activity. Unexpectedly, the growth inhibitory effect of F. oxysporum α-pheromone was independent of the cognate G protein-coupled receptors Ste2 and of the central β-turn but instead required two conserved Trp(1)-Cys(2) residues at the N terminus. These results indicate that, despite their reduced size, fungal α-pheromones contain discrete functional regions with a defined secondary structure that regulate diverse biological processes such as polarity reorientation and cell division. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  1. Differences in sensitivity to the fungal pathogen Batrachochytrium dendrobatidis among amphibian populations.

    Science.gov (United States)

    Bradley, Paul W; Gervasi, Stephanie S; Hua, Jessica; Cothran, Rickey D; Relyea, Rick A; Olson, Deanna H; Blaustein, Andrew R

    2015-10-01

    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, there is little information on whether sensitivity to Bd differs among populations, which is essential for understanding Bd-infection dynamics and for formulating conservation strategies. We experimentally investigated intraspecific differences in host sensitivity to Bd across 10 populations of wood frogs (Lithobates sylvaticus) raised from eggs to metamorphosis. We exposed the post-metamorphic wood frogs to Bd and monitored survival for 30 days under controlled laboratory conditions. Populations differed in overall survival and mortality rate. Infection load also differed among populations but was not correlated with population differences in risk of mortality. Such population-level variation in sensitivity to Bd may result in reservoir populations that may be a source for the transmission of Bd to other sensitive populations or species. Alternatively, remnant populations that are less sensitive to Bd could serve as sources for recolonization after epidemic events. © 2015 Society for Conservation Biology.

  2. Decreased Polysaccharide Feruloylation Compromises Plant Cell Wall Integrity and Increases Susceptibility to Necrotrophic Fungal Pathogens.

    Science.gov (United States)

    Reem, Nathan T; Pogorelko, Gennady; Lionetti, Vincenzo; Chambers, Lauran; Held, Michael A; Bellincampi, Daniela; Zabotina, Olga A

    2016-01-01

    The complexity of cell wall composition and structure determines the strength, flexibility, and function of the primary cell wall in plants. However, the contribution of the various components to cell wall integrity (CWI) and function remains unclear. Modifications of cell wall composition can induce plant responses known as CWI control. In this study, we used transgenic expression of the fungal feruloyl esterase AnFAE to examine the effect of post-synthetic modification of Arabidopsis and Brachypodium cell walls. Transgenic Arabidopsis plants expressing AnFAE showed a significant reduction of monomeric ferulic acid, decreased amounts of wall-associated extensins, and increased susceptibility to Botrytis cinerea, compared with wild type. Transgenic Brachypodium showed reductions in monomeric and dimeric ferulic acids and increased susceptibility to Bipolaris sorokiniana. Upon infection, transgenic Arabidopsis and Brachypodium plants also showed increased expression of several defense-related genes compared with wild type. These results demonstrate a role, in both monocot and dicot plants, of polysaccharide feruloylation in plant CWI, which contributes to plant resistance to necrotrophic pathogens.

  3. Decreased Polysaccharide Feruloylation Compromises Plant Cell Wall Integrity and Increases Susceptibility to Necrotrophic Fungal Pathogens

    Directory of Open Access Journals (Sweden)

    Nathan T Reem

    2016-05-01

    Full Text Available The complexity of cell wall composition and structure determines the strength, flexibility, and function of the primary cell wall in plants. However, the contribution of the various components to cell wall integrity and function remains unclear. Modifications of cell wall composition can induce plant responses known as Cell Wall Integrity control. In this study, we used transgenic expression of the fungal feruloyl esterase AnFAE to examine the effect of post-synthetic modification of Arabidopsis and Brachypodium cell walls. Transgenic Arabidopsis plants expressing AnFAE showed a significant reduction of monomeric ferulic acid, increased amounts of wall-associated extensins, and increased susceptibility to Botrytis cinerea, compared with wild type. Transgenic Brachypodium showed reductions in monomeric and dimeric ferulic acids and increased susceptibility to Bipolaris sorokiniana. Upon infection, transgenic Arabidopsis and Brachypodium plants also showed increased expression of several defense-related genes compared with wild type. These results demonstrate a role, in both monocot and dicot plants, of polysaccharide feruloylation in plant cell wall integrity, which contributes to plant resistance to necrotrophic pathogens.

  4. Fungal naphtho-γ-pyrones: Potent antibiotics for drug-resistant microbial pathogens.

    Science.gov (United States)

    He, Yan; Tian, Jun; Chen, Xintao; Sun, Weiguang; Zhu, Hucheng; Li, Qin; Lei, Liang; Yao, Guangmin; Xue, Yongbo; Wang, Jianping; Li, Hua; Zhang, Yonghui

    2016-04-11

    Four naphtho-γ-pyrones (fonsecinones A and C and aurasperones A and E) were identified as potential antibacterial agents against Escherichia coli, extended-spectrum β-lactamase (ESBL)-producing E. coli, Pseudomonas aeruginosa, Enterococcus faecalis, and methicillin-resistant Staphylococcus aureus (MRSA) in an in vitro antibacterial screen of 218 fungal metabolites. Fonsecinone A (2) exhibited the most potent antibacterial activity, with minimum inhibitory concentrations (MICs) of 4.26, 17.04, and 4.26 μg/mL against ESBL-producing E. coli, P. aeruginosa, and E. faecalis, respectively. The inhibitory effects of fonsecinones A (2) and C (3) against E. coli and ESBL-producing E. coli were comparable to those of amikacin. Molecular docking-based target identification of naphtho-γ-pyrones 1-8 revealed bacterial enoyl-acyl carrier protein reductase (FabI) as an antibacterial target, which was further validated by FabI affinity and inhibition assays. Fonsecinones A (2) and C (3) and aurasperones A (6) and E (7) bound FabI specifically and produced concentration-dependent inhibition effects. This work is the first report of anti-drug-resistant bacterial activities of naphtho-γ-pyrones 1-8 and their possible antibacterial mechanism of action and provides an example of the successful application of in silico methods for drug target identification and validation and the identification of new lead antibiotic compounds against drug-resistant pathogens.

  5. Force nanoscopy of hydrophobic interactions in the fungal pathogen Candida glabrata.

    Science.gov (United States)

    El-Kirat-Chatel, Sofiane; Beaussart, Audrey; Derclaye, Sylvie; Alsteens, David; Kucharíková, Soňa; Van Dijck, Patrick; Dufrêne, Yves F

    2015-02-24

    Candida glabrata is an opportunistic human fungal pathogen which binds to surfaces mainly through the Epa family of cell adhesion proteins. While some Epa proteins mediate specific lectin-like interactions with human epithelial cells, others promote adhesion and biofilm formation on plastic surfaces via nonspecific interactions that are not yet elucidated. We report the measurement of hydrophobic forces engaged in Epa6-mediated cell adhesion by means of atomic force microscopy (AFM). Using single-cell force spectroscopy, we found that C. glabrata wild-type (WT) cells attach to hydrophobic surfaces via strongly adhesive macromolecular bonds, while mutant cells impaired in Epa6 expression are weakly adhesive. Nanoscale mapping of yeast cells using AFM tips functionalized with hydrophobic groups shows that Epa6 is massively exposed on WT cells and conveys strong hydrophobic properties to the cell surface. Our results demonstrate that Epa6 mediates strong hydrophobic interactions, thereby providing a molecular basis for the ability of this adhesin to drive biofilm formation on abiotic surfaces.

  6. Hydrogen peroxide acts on sensitive mitochondrial proteins to induce death of a fungal pathogen revealed by proteomic analysis.

    Directory of Open Access Journals (Sweden)

    Guozheng Qin

    Full Text Available How the host cells of plants and animals protect themselves against fungal invasion is a biologically interesting and economically important problem. Here we investigate the mechanistic process that leads to death of Penicillium expansum, a widespread phytopathogenic fungus, by identifying the cellular compounds affected by hydrogen peroxide (H(2O(2 that is frequently produced as a response of the host cells. We show that plasma membrane damage was not the main reason for H(2O(2-induced death of the fungal pathogen. Proteomic analysis of the changes of total cellular proteins in P. expansum showed that a large proportion of the differentially expressed proteins appeared to be of mitochondrial origin, implying that mitochondria may be involved in this process. We then performed mitochondrial sub-proteomic analysis to seek the H(2O(2-sensitive proteins in P. expansum. A set of mitochondrial proteins were identified, including respiratory chain complexes I and III, F(1F(0 ATP synthase, and mitochondrial phosphate carrier protein. The functions of several proteins were further investigated to determine their effects on the H(2O(2-induced fungal death. Through fluorescent co-localization and the use of specific inhibitor, we provide evidence that complex III of the mitochondrial respiratory chain contributes to ROS generation in fungal mitochondria under H(2O(2 stress. The undesirable accumulation of ROS caused oxidative damage of mitochondrial proteins and led to the collapse of mitochondrial membrane potential. Meanwhile, we demonstrate that ATP synthase is involved in the response of fungal pathogen to oxidative stress, because inhibition of ATP synthase by oligomycin decreases survival. Our data suggest that mitochondrial impairment due to functional alteration of oxidative stress-sensitive proteins is associated with fungal death caused by H(2O(2.

  7. Chlorine-rich plasma polymer coating for the prevention of attachment of pathogenic fungal cells onto materials surfaces

    Science.gov (United States)

    Lamont-Friedrich, Stephanie J.; Michl, Thomas D.; Giles, Carla; Griesser, Hans J.; Coad, Bryan R.

    2016-07-01

    The attachment of pathogenic fungal cells onto materials surfaces, which is often followed by biofilm formation, causes adverse consequences in a wide range of areas. Here we have investigated the ability of thin film coatings from chlorinated molecules to deter fungal colonization of solid materials by contact killing of fungal cells reaching the surface of the coating. Coatings were deposited onto various substrate materials via plasma polymerization, which is a substrate-independent process widely used for industrial coating applications, using 1,1,2-trichloroethane as the process vapour. XPS surface analysis showed that the coatings were characterized by a highly chlorinated hydrocarbon polymer nature, with only a very small amount of oxygen incorporated. The activity of these coatings against human fungal pathogens was quantified using a recently developed, modified yeast assay and excellent antifungal activity was observed against Candida albicans and Candida glabrata. Plasma polymer surface coatings derived from chlorinated hydrocarbon molecules may therefore offer a promising solution to preventing yeast and mould biofilm formation on materials surfaces, for applications such as air conditioners, biomedical devices, food processing equipment, and others.

  8. An Antifungal Combination Matrix Identifies a Rich Pool of Adjuvant Molecules that Enhance Drug Activity against Diverse Fungal Pathogens

    Directory of Open Access Journals (Sweden)

    Nicole Robbins

    2015-11-01

    Full Text Available There is an urgent need to identify new treatments for fungal infections. By combining sub-lethal concentrations of the known antifungals fluconazole, caspofungin, amphotericin B, terbinafine, benomyl, and cyprodinil with ∼3,600 compounds in diverse fungal species, we generated a deep reservoir of chemical-chemical interactions termed the Antifungal Combinations Matrix (ACM. Follow-up susceptibility testing against a fluconazole-resistant isolate of C. albicans unveiled ACM combinations capable of potentiating fluconazole in this clinical strain. We used chemical genetics to elucidate the mode of action of the antimycobacterial drug clofazimine, a compound with unreported antifungal activity that synergized with several antifungals. Clofazimine induces a cell membrane stress for which the Pkc1 signaling pathway is required for tolerance. Additional tests against additional fungal pathogens, including Aspergillus fumigatus, highlighted that clofazimine exhibits efficacy as a combination agent against multiple fungi. Thus, the ACM is a rich reservoir of chemical combinations with therapeutic potential against diverse fungal pathogens.

  9. Simultaneous transcriptome analysis of Colletotrichum gloeosporioides and tomato fruit pathosystem reveals novel fungal pathogenicity and fruit defense strategies.

    Science.gov (United States)

    Alkan, Noam; Friedlander, Gilgi; Ment, Dana; Prusky, Dov; Fluhr, Robert

    2015-01-01

    The fungus Colletotrichum gloeosporioides breaches the fruit cuticle but remains quiescent until fruit ripening signals a switch to necrotrophy, culminating in devastating anthracnose disease. There is a need to understand the distinct fungal arms strategy and the simultaneous fruit response. Transcriptome analysis of fungal-fruit interactions was carried out concurrently in the appressoria, quiescent and necrotrophic stages. Conidia germinating on unripe fruit cuticle showed stage-specific transcription that was accompanied by massive fruit defense responses. The subsequent quiescent stage showed the development of dendritic-like structures and swollen hyphae within the fruit epidermis. The quiescent fungal transcriptome was characterized by activation of chromatin remodeling genes and unsuspected environmental alkalization. Fruit response was portrayed by continued highly integrated massive up-regulation of defense genes. During cuticle infection of green or ripe fruit, fungi recapitulate the same developmental stages but with differing quiescent time spans. The necrotrophic stage showed a dramatic shift in fungal metabolism and up-regulation of pathogenicity factors. Fruit response to necrotrophy showed activation of the salicylic acid pathway, climaxing in cell death. Transcriptome analysis of C. gloeosporioides infection of fruit reveals its distinct stage-specific lifestyle and the concurrent changing fruit response, deepening our perception of the unfolding fungal-fruit arms and defenses race.

  10. Volatiles Emitted from Maize Ears Simultaneously Infected with Two Fusarium Species Mirror the Most Competitive Fungal Pathogen

    Science.gov (United States)

    Sherif, Mohammed; Becker, Eva-Maria; Herrfurth, Cornelia; Feussner, Ivo; Karlovsky, Petr; Splivallo, Richard

    2016-01-01

    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 Fusarium graminearum 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 the 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. PMID:27729923

  11. Volatiles emitted from maize ears simultaneously infected with two Fusarium species mirror the most competitive fungal pathogen

    Directory of Open Access Journals (Sweden)

    Mohammed Sherif

    2016-09-01

    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.

  12. Constraints of simultaneous resistance to a fungal pathogen and an insect herbivore in lima bean (Phaseolus lunatus L.).

    Science.gov (United States)

    Ballhorn, Daniel J

    2011-02-01

    The existence of tradeoffs among plant defenses is commonly accepted, however, actual evidence for these tradeoffs is scarce. In this study, I analyzed effects of different direct defenses of wild lima bean plants (Phaseolus lunatus) that were simultaneously exposed to a fungal pathogen (Colletotrichum lindemuthianum) and an insect herbivore, the Mexican bean beetle (Epilachna varivestis). Although plants were derived from spatially widely separated populations, I observed a common tradeoff between resistance to pathogens and herbivores. Plants with high levels of anti-herbivore defense (cyanogenesis) showed low levels of resistance to pathogens (polyphenol oxidase activity and phenolic compounds), and vice versa. Competition for resources generally is considered to be the basis for tradeoffs. However, I report direct inhibition of polyphenol oxidase by cyanide, making simultaneous expression of both defenses at high levels impossible. I argue that populations composed of individuals investing in one type of defense have an advantage in environments that periodically favor either pathogen or herbivore plant antagonists.

  13. Enhanced resistance in Theobroma cacao against oomycete and fungal pathogens by secretion of phosphatidylinositol-3-phosphate-binding proteins.

    Science.gov (United States)

    Helliwell, Emily E; Vega-Arreguín, Julio; Shi, Zi; Bailey, Bryan; Xiao, Shunyuan; Maximova, Siela N; Tyler, Brett M; Guiltinan, Mark J

    2016-03-01

    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.

  14. HIGS: Host-Induced Gene Silencing in the Obligate Biotrophic Fungal Pathogen Blumeria graminis[W][OA

    Science.gov (United States)

    Nowara, Daniela; Gay, Alexandra; Lacomme, Christophe; Shaw, Jane; Ridout, Christopher; Douchkov, Dimitar; Hensel, Götz; Kumlehn, Jochen; Schweizer, Patrick

    2010-01-01

    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

  15. A thaumatin-like protein of Ocimum basilicum confers tolerance to fungal pathogen and abiotic stress in transgenic Arabidopsis.

    Science.gov (United States)

    Misra, Rajesh Chandra; Sandeep; Kamthan, Mohan; Kumar, Santosh; Ghosh, Sumit

    2016-05-06

    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.

  16. Occurrence and diversity of fungal pathogens associated with water hyacinth and their potential as biocontrol agents in the Rift Valley of Ethiopia

    NARCIS (Netherlands)

    Gebregiorgis, Firehun; Struik, P.C.; Lantinga, E.A.; Tessema, Taye

    2017-01-01

    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 th

  17. Molecular cloning and functional analysis of three genes encoding polygalacturonase-inhibiting proteins from Capsicum annuum, and their relation to increased resistance to two fungal pathogens

    Science.gov (United States)

    Polygalacturonase-inhibiting proteins (PGIPs) are plant cell wall glycoproteins that can inhibit fungal endopolygalacturonases (PGs). Inhibiting by PGIPs directly reduces potential PG activity in specific plant pathogenic fungi, reducing their aggressiveness. Here, we isolated and functionally chara...

  18. The genomes of the fungal plant pathogens Cladosporium fulvum and Dothistroma septosporum reveal adaptation to different hosts and lifestyles but also signatures of common ancestry.

    NARCIS (Netherlands)

    de Wit, P.J.G.M.; van der Burgt, A.; Ökmen, B.; Stergiopoulos, I.; Abd-Elsalam, K.A.; Aerts, A.L.; Bahkali, A.H.; Beenen, H.G.; Chettri, P.; Cox, M.P.; Datema, E.; de Vries, R.P.; Dhillon, B.; Ganley, A.R.; Griffiths, S.A.; Guo, Y.; Hamelin, R.C.; Henrissat, B.; Kabir, M.S.; Jashni, M.K.; Kema, G.; Klaubauf, S.; Lapidus, A.; Levasseur, A.; Lindquist, E.; Mehrabi, R.; Ohm, R.A.; Owen, T.J.; Salamov, A.; Schwelm, A.; Schijlen, E.; Sun, H.; van den Burg, H.A.; van Ham, R.C.H.J.; Zhang, S.; Goodwin, S.B.; Grigoriev, I.V.; Collemare, J.; Bradshaw, R.E.

    2012-01-01

    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

  19. The Role of Mitogen-Activated Protein (MAP Kinase Signaling Components in the Fungal Development, Stress Response and Virulence of the Fungal Cereal Pathogen Bipolaris sorokiniana.

    Directory of Open Access Journals (Sweden)

    Yueqiang Leng

    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

  20. The Role of Mitogen-Activated Protein (MAP) Kinase Signaling Components in the Fungal Development, Stress Response and Virulence of the Fungal Cereal Pathogen Bipolaris sorokiniana.

    Science.gov (United States)

    Leng, Yueqiang; Zhong, Shaobin

    2015-01-01

    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 development under

  1. β-1,3-Glucan recognition protein (βGRP) is essential for resistance against fungal pathogen and opportunistic pathogenic gut bacteria in Locusta migratoria manilensis.

    Science.gov (United States)

    Zheng, Xiaoli; Xia, Yuxian

    2012-03-01

    Pattern recognition proteins, which form part of the innate immune system, initiate host defense reactions in response to pathogen surface molecules. The pattern recognition protein β-1,3-glucan recognition protein (βGRP) binds to β-1,3-glucan on fungal surfaces to mediate melanization via the prophenoloxidase (PPO)-activating cascade. In this study, cDNA encoding a 53-kDa βGRP (LmβGRP) was cloned from Locusta migratoria manilensis. LmβGRP mRNA shown to be constitutively expressed specifically in hemocytes and was highly upregulated following fungal infection. LmβGRP-silenced (LmβGRP-RNAi) mutant locusts exhibited significantly reduced survival rate following fungal infection (Metarhizium acridum) compared with the wild-type. Furthermore, LmβGRP-RNAi mutants exhibited abnormally loose stools indicative of a gut defect. 16S rRNA gene analysis detected the opportunistic pathogenic bacterium, Vibrio vulnificus in LmβGRP mutant but not wild-type locusts, suggesting changes in the composition of gut bacterial communities. These results indicate that LmβGRP is essential to gut immunity in L. migratoria manilensis.

  2. Elemental Sulfur and Thiol Accumulation in Tomato and Defense against a Fungal Vascular Pathogen1

    Science.gov (United States)

    Williams, Jane S.; Hall, Sharon A.; Hawkesford, Malcolm J.; Beale, Michael H.; Cooper, Richard M.

    2002-01-01

    The occurrence of fungicidal, elemental S is well documented in certain specialized prokaryotes, but has rarely been detected in eukaryotes. Elemental S was first identified in this laboratory as a novel phytoalexin in the xylem of resistant genotypes of Theobroma cacao, after infection by the vascular, fungal pathogen Verticillium dahliae. In the current work, this phenomenon is demonstrated in a resistant line of tomato, Lycopersicon esculentum, in response to V. dahliae. A novel gas chromatography-mass spectroscopy method using isotope dilution analysis with 34S internal standard was developed to identify unambiguously and quantify 32S in samples of excised xylem. Accumulation of S in vascular tissue was more rapid and much greater in the disease-resistant than in the disease-susceptible line. Levels of S detected in the resistant variety (approximately 10 μg g−1 fresh weight excised xylem) were fungitoxic to V. dahliae (spore germination was inhibited >90% at approximately 3 μg mL−1). Scanning electron microscopy-energy dispersive x-ray microanalysis confirmed accumulation of S in vascular but not in pith cells and in greater amounts and frequency in the Verticillium spp.-resistant genotype. More intensive localizations of S were occasionally detected in xylem parenchyma cells, vessel walls, vascular gels, and tyloses, structures in potential contact with and linked with defense to V. dahliae. Transient increases in concentrations of sulfate, glutathione, and Cys of vascular tissues from resistant but not susceptible lines after infection may indicate a perturbation of S metabolism induced by elemental S formation; this is discussed in terms of possible S biogenesis. PMID:11788760

  3. Population Genetic Analyses of the Fungal Pathogen Colletotrichum fructicola on Tea-Oil Trees in China

    Science.gov (United States)

    Li, He; Zhou, Guo-Ying; Liu, Jun-Ang; Xu, Jianping

    2016-01-01

    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

  4. Isolation and purification of fungal pathogen (Macrophomina phaseolina induced chitinase from moth beans (Phaseolus aconitifolius

    Directory of Open Access Journals (Sweden)

    Neelima Garg

    2010-01-01

    Full Text Available Objective : Chitinase (EC 3.2.1.14 is one of the major pathogenesis-related proteins, which is a polypeptide that accumulates extracellularly in infected plant tissue. An attempt was made to isolate and purify the chitanase enzyme using moth beans as an enzyme source. Materials and Method : The enzyme was isolated and purified from moth beans against the fungal pathogen Macrophomina phaseolina strain 2165. The isolation and purification was done in both in vitro and in vivo conditions. Purification of chitinase was carried out to obtain three fractions, viz. 50°C heated, ammonium sulfate precipitated and sephadex G-25 column-eluted fractions. The molecular mass of Chitinase was directly estimated by sodium dodecyl sulfate-polyacryamide gel electroresis (SDS-PAGE. Result : The yield is sufficient for initial characterization studies of the enzyme. The molecular study of the enzyme shows the possibility of generating the defense mechanism in plants in which it cannot occur. Chitinase was purified by gel filtration chromatography with 20.75-fold and 32.78-fold purification in the in vitro and in vivo conditions, respectively. The enzyme shows a maximum activity after 90 min with 0.1 ml of colloidal chitin as a substrate and 0.4 ml of crude chitinase extract. The optimum pH of 5.0 and an optimum temperature of 40°C was found for maximal activity. The molecular weight of purified chitinase was estimated to be 30 kDa by SDS-PAGE. Conclusion : The chitinase isolated in both in vitro and in vivo conditions is stable andactive.

  5. Isolation and purification of fungal pathogen (Macrophomina phaseolina) induced chitinase from moth beans (Phaseolus aconitifolius).

    Science.gov (United States)

    Garg, Neelima; Gupta, Himanshu

    2010-01-01

    Chitinase (EC 3.2.1.14) is one of the major pathogenesis-related proteins, which is a polypeptide that accumulates extracellularly in infected plant tissue. An attempt was made to isolate and purify the chitanase enzyme using moth beans as an enzyme source. The enzyme was isolated and purified from moth beans against the fungal pathogen Macrophomina phaseolina strain 2165. The isolation and purification was done in both in vitro and in vivo conditions. Purification of chitinase was carried out to obtain three fractions, viz. 50°C heated, ammonium sulfate precipitated and sephadex G-25 column-eluted fractions. The molecular mass of Chitinase was directly estimated by sodium dodecyl sulfate-polyacryamide gel electroresis (SDS-PAGE). The yield is sufficient for initial characterization studies of the enzyme. The molecular study of the enzyme shows the possibility of generating the defense mechanism in plants in which it cannot occur. Chitinase was purified by gel filtration chromatography with 20.75-fold and 32.78-fold purification in the in vitro and in vivo conditions, respectively. The enzyme shows a maximum activity after 90 min with 0.1 ml of colloidal chitin as a substrate and 0.4 ml of crude chitinase extract. The optimum pH of 5.0 and an optimum temperature of 40°C was found for maximal activity. The molecular weight of purified chitinase was estimated to be 30 kDa by SDS-PAGE. The chitinase isolated in both in vitro and in vivo conditions is stable andactive.

  6. Integrative Model of Oxidative Stress Adaptation in the Fungal Pathogen Candida albicans.

    Directory of Open Access Journals (Sweden)

    Chandrasekaran Komalapriya

    Full Text Available The major fungal pathogen of humans, Candida albicans, mounts robust responses to oxidative stress that are critical for its virulence. These responses counteract the reactive oxygen species (ROS that are generated by host immune cells in an attempt to kill the invading fungus. Knowledge of the dynamical processes that instigate C. albicans oxidative stress responses is required for a proper understanding of fungus-host interactions. Therefore, we have adopted an interdisciplinary approach to explore the dynamical responses of C. albicans to hydrogen peroxide (H2O2. Our deterministic mathematical model integrates two major oxidative stress signalling pathways (Cap1 and Hog1 pathways with the three major antioxidant systems (catalase, glutathione and thioredoxin systems and the pentose phosphate pathway, which provides reducing equivalents required for oxidative stress adaptation. The model encapsulates existing knowledge of these systems with new genomic, proteomic, transcriptomic, molecular and cellular datasets. Our integrative approach predicts the existence of alternative states for the key regulators Cap1 and Hog1, thereby suggesting novel regulatory behaviours during oxidative stress. The model reproduces both existing and new experimental observations under a variety of scenarios. Time- and dose-dependent predictions of the oxidative stress responses for both wild type and mutant cells have highlighted the different temporal contributions of the various antioxidant systems during oxidative stress adaptation, indicating that catalase plays a critical role immediately following stress imposition. This is the first model to encapsulate the dynamics of the transcriptional response alongside the redox kinetics of the major antioxidant systems during H2O2 stress in C. albicans.

  7. Integrative Model of Oxidative Stress Adaptation in the Fungal Pathogen Candida albicans.

    Science.gov (United States)

    Komalapriya, Chandrasekaran; Kaloriti, Despoina; Tillmann, Anna T; Yin, Zhikang; Herrero-de-Dios, Carmen; Jacobsen, Mette D; Belmonte, Rodrigo C; Cameron, Gary; Haynes, Ken; Grebogi, Celso; de Moura, Alessandro P S; Gow, Neil A R; Thiel, Marco; Quinn, Janet; Brown, Alistair J P; Romano, M Carmen

    2015-01-01

    The major fungal pathogen of humans, Candida albicans, mounts robust responses to oxidative stress that are critical for its virulence. These responses counteract the reactive oxygen species (ROS) that are generated by host immune cells in an attempt to kill the invading fungus. Knowledge of the dynamical processes that instigate C. albicans oxidative stress responses is required for a proper understanding of fungus-host interactions. Therefore, we have adopted an interdisciplinary approach to explore the dynamical responses of C. albicans to hydrogen peroxide (H2O2). Our deterministic mathematical model integrates two major oxidative stress signalling pathways (Cap1 and Hog1 pathways) with the three major antioxidant systems (catalase, glutathione and thioredoxin systems) and the pentose phosphate pathway, which provides reducing equivalents required for oxidative stress adaptation. The model encapsulates existing knowledge of these systems with new genomic, proteomic, transcriptomic, molecular and cellular datasets. Our integrative approach predicts the existence of alternative states for the key regulators Cap1 and Hog1, thereby suggesting novel regulatory behaviours during oxidative stress. The model reproduces both existing and new experimental observations under a variety of scenarios. Time- and dose-dependent predictions of the oxidative stress responses for both wild type and mutant cells have highlighted the different temporal contributions of the various antioxidant systems during oxidative stress adaptation, indicating that catalase plays a critical role immediately following stress imposition. This is the first model to encapsulate the dynamics of the transcriptional response alongside the redox kinetics of the major antioxidant systems during H2O2 stress in C. albicans.

  8. Coincident mass extirpation of neotropical amphibians with the emergence of the infectious fungal pathogen Batrachochytrium dendrobatidis.

    Science.gov (United States)

    Cheng, Tina L; Rovito, Sean M; Wake, David B; Vredenburg, Vance T

    2011-06-01

    Amphibians highlight the global biodiversity crisis because ∼40% of all amphibian species are currently in decline. Species have disappeared even in protected habitats (e.g., the enigmatic extinction of the golden toad, Bufo periglenes, from Costa Rica). The emergence of a fungal pathogen, Batrachochytrium dendrobatidis (Bd), has been implicated in a number of declines that have occurred in the last decade, but few studies have been able to test retroactively whether Bd emergence was linked to earlier declines and extinctions. We describe a noninvasive PCR sampling technique that detects Bd in formalin-preserved museum specimens. We detected Bd by PCR in 83-90% (n = 38) of samples that were identified as positive by histology. We examined specimens collected before, during, and after major amphibian decline events at established study sites in southern Mexico, Guatemala, and Costa Rica. A pattern of Bd emergence coincident with decline at these localities is revealed-the absence of Bd over multiple years at all localities followed by the concurrent emergence of Bd in various species at each locality during a period of population decline. The geographical and chronological emergence of Bd at these localities also indicates a southbound spread from southern Mexico in the early 1970s to western Guatemala in the 1980s/1990s and to Monteverde, Costa Rica by 1987. We find evidence of a historical "Bd epidemic wave" that began in Mexico and subsequently spread to Central America. We describe a technique that can be used to screen museum specimens from other amphibian decline sites around the world.

  9. Population Genetic Analyses of the Fungal Pathogen Colletotrichum fructicola on Tea-Oil Trees in China.

    Directory of Open Access Journals (Sweden)

    He Li

    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.

  10. Population Genetic Analyses of the Fungal Pathogen Colletotrichum fructicola on Tea-Oil Trees in China.

    Science.gov (United States)

    Li, He; Zhou, Guo-Ying; Liu, Jun-Ang; Xu, Jianping

    2016-01-01

    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.

  11. Defining the predicted protein secretome of the fungal wheat leaf pathogen Mycosphaerella graminicola.

    Directory of Open Access Journals (Sweden)

    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.

  12. Regulatory network modelling of iron acquisition by a fungal pathogen in contact with epithelial cells

    Directory of Open Access Journals (Sweden)

    Guthke Reinhard

    2010-11-01

    Full Text Available Abstract Background Reverse engineering of gene regulatory networks can be used to predict regulatory interactions of an organism faced with environmental changes, but can prove problematic, especially when focusing on complicated multi-factorial processes. Candida albicans is a major human fungal pathogen. During the infection process, this fungus is able to adapt to conditions of very low iron availability. Such adaptation is an important virulence attribute of virtually all pathogenic microbes. Understanding the regulation of iron acquisition genes will extend our knowledge of the complex regulatory changes during the infection process and might identify new potential drug targets. Thus, there is a need for efficient modelling approaches predicting key regulatory events of iron acquisition genes during the infection process. Results This study deals with the regulation of C. albicans iron uptake genes during adhesion to and invasion into human oral epithelial cells. A reverse engineering strategy is presented, which is able to infer regulatory networks on the basis of gene expression data, making use of relevant selection criteria such as sparseness and robustness. An exhaustive use of available knowledge from different data sources improved the network prediction. The predicted regulatory network proposes a number of new target genes for the transcriptional regulators Rim101, Hap3, Sef1 and Tup1. Furthermore, the molecular mode of action for Tup1 is clarified. Finally, regulatory interactions between the transcription factors themselves are proposed. This study presents a model describing how C. albicans may regulate iron acquisition during contact with and invasion of human oral epithelial cells. There is evidence that some of the proposed regulatory interactions might also occur during oral infection. Conclusions This study focuses on a typical problem in Systems Biology where an interesting biological phenomenon is studied using a small

  13. Lessons from interactions within the cassava green mite fungal pathogen Neozygites tanajoae system and prospects for microbial control using Entomophthorales.

    Science.gov (United States)

    Hountondji, Fabien C C

    2008-12-01

    Most fungal pathogens lack the capacity to search for their host but rather develop sit-and-wait strategies that favour contact with them. The success of these strategies depends upon the interactions of the pathogen with its host, the host plant and the environmental conditions, which altogether determine its transmissibility. Given the limited success that has characterized application of sustainable microbial control, particularly using Entomophthorales, interaction studies have been conducted with the entomophthoralean fungus Neozygites tanajoae, pathogenic to the cassava green mite (CGM), Mononychellus tanajoa, to help understand differences observed between laboratory and field performances of this pathogen. Reciprocal pathogen-host interactions as well as tritrophic interactions involving the host plant were studied. It was found that herbivory triggers the release of volatiles that promote sporulation of isolates of N. tanajoae, whereas the host mite avoids haloes of spores of this pathogen. However, the host mite does not avoid the pathogen when inside the mummified fungus-killed cadaver. The status of microbial control of CGM in Africa is reviewed and implications of these interactions are discussed for prospective application of microbial control using Entomophthorales.

  14. The novel fungal-specific gene FUG1 has a role in pathogenicity and fumonisin biosynthesis in Fusarium verticillioides.

    Science.gov (United States)

    Ridenour, John B; Bluhm, Burton H

    2017-05-01

    Fusarium verticillioides is a globally important pathogen of maize, capable of causing severe yield reductions and economic losses. In addition, F. verticillioides produces toxic secondary metabolites during kernel colonization that pose significant threats to human and animal health. Fusarium verticillioides and other plant-pathogenic fungi possess a large number of genes with no known or predicted function, some of which could encode novel virulence factors or antifungal targets. In this study, we identified and characterized the novel gene FUG1 (Fungal Unknown Gene 1) in F. verticillioides through functional genetics. Deletion of FUG1 impaired maize kernel colonization and fumonisin biosynthesis. In addition, deletion of FUG1 increased sensitivity to the antimicrobial compound 2-benzoxazolinone and to hydrogen peroxide, which indicates that FUG1 may play a role in mitigating stresses associated with host defence. Transcriptional profiling via RNA-sequencing (RNA-seq) identified numerous fungal genes that were differentially expressed in the kernel environment following the deletion of FUG1, including genes involved in secondary metabolism and mycelial development. Sequence analysis of the Fug1 protein provided evidence for nuclear localization, DNA binding and a domain of unknown function associated with previously characterized transcriptional regulators. This information, combined with the observed transcriptional reprogramming in the deletion mutant, suggests that FUG1 represents a novel class of fungal transcription factors or genes otherwise involved in signal transduction. © 2016 BSPP AND JOHN WILEY & SONS LTD.

  15. Immunodetection of fungal and oomycete pathogens: established and emerging threats to human health, animal welfare and global food security.

    Science.gov (United States)

    Thornton, Christopher R; Wills, Odette E

    2015-02-01

    Filamentous fungi (moulds), yeast-like fungi, and oomycetes cause life-threatening infections of humans and animals and are a major constraint to global food security, constituting a significant economic burden to both agriculture and medicine. As well as causing localized or systemic infections, certain species are potent producers of allergens and toxins that exacerbate respiratory diseases or cause cancer and organ damage. We review the pathogenic and toxigenic organisms that are etiologic agents of both animal and plant diseases or that have recently emerged as serious pathogens of immunocompromised individuals. The use of hybridoma and phage display technologies and their success in generating monoclonal antibodies for the detection and control of fungal and oomycete pathogens are explored. Monoclonal antibodies hold enormous potential for the development of rapid and specific tests for the diagnosis of human mycoses, however, unlike plant pathology, their use in medical mycology remains to be fully exploited.

  16. Doxycycline-regulated gene expression in the opportunistic fungal pathogen Aspergillus fumigatus

    Directory of Open Access Journals (Sweden)

    Askew David S

    2005-01-01

    Full Text Available Abstract Background Although Aspergillus fumigatus is an important human fungal pathogen there are few expression systems available to study the contribution of specific genes to the growth and virulence of this opportunistic mould. Regulatable promoter systems based upon prokaryotic regulatory elements in the E. coli tetracycline-resistance operon have been successfully used to manipulate gene expression in several organisms, including mice, flies, plants, and yeast. However, the system has not yet been adapted for Aspergillus spp. Results Here we describe the construction of plasmid vectors that can be used to regulate gene expression in A. fumigatus using a simple co-transfection approach. Vectors were generated in which the tetracycline transactivator (tTA or the reverse tetracycline transactivator (rtTA2s-M2 are controlled by the A. nidulans gpdA promoter. Dominant selectable cassettes were introduced into each plasmid, allowing for selection following gene transfer into A. fumigatus by incorporating phleomycin or hygromycin into the medium. To model an essential gene under tetracycline regulation, the E. coli hygromycin resistance gene, hph, was placed under the control of seven copies of the TetR binding site (tetO7 in a plasmid vector and co-transfected into A. fumigatus protoplasts together with one of the two transactivator plasmids. Since the hph gene is essential to A. fumigatus in the presence of hygromycin, resistance to hygromycin was used as a marker of hph reporter gene expression. Transformants were identified in which the expression of tTA conferred hygromycin resistance by activating expression of the tetO7-hph reporter gene, and the addition of doxycycline to the medium suppressed hygromycin resistance in a dose-dependent manner. Similarly, transformants were identified in which expression of rtTA2s-M2 conferred hygromycin resistance only in the presence of doxycycline. The levels of doxycycline required to regulate

  17. Increase of Fungal Pathogenicity and Role of Plant Glutamine in Nitrogen-Induced Susceptibility (NIS) To Rice Blast

    Science.gov (United States)

    Huang, Huichuan; Nguyen Thi Thu, Thuy; He, Xiahong; Gravot, Antoine; Bernillon, Stéphane; Ballini, Elsa; Morel, Jean-Benoit

    2017-01-01

    Highlight  Modifications in glutamine synthetase OsGS1-2 expression and fungal pathogenicity underlie nitrogen-induced susceptibility to rice blast. Understanding why nitrogen fertilization increase the impact of many plant diseases is of major importance. The interaction between Magnaporthe oryzae and rice was used as a model for analyzing the molecular mechanisms underlying Nitrogen-Induced Susceptibility (NIS). We show that our experimental system in which nitrogen supply strongly affects rice blast susceptibility only slightly affects plant growth. In order to get insights into the mechanisms of NIS, we conducted a dual RNA-seq experiment on rice infected tissues under two nitrogen fertilization regimes. On the one hand, we show that enhanced susceptibility was visible despite an over-induction of defense gene expression by infection under high nitrogen regime. On the other hand, the fungus expressed to high levels effectors and pathogenicity-related genes in plants under high nitrogen regime. We propose that in plants supplied with elevated nitrogen fertilization, the observed enhanced induction of plant defense is over-passed by an increase in the expression of the fungal pathogenicity program, thus leading to enhanced susceptibility. Moreover, some rice genes implicated in nitrogen recycling were highly induced during NIS. We further demonstrate that the OsGS1-2 glutamine synthetase gene enhances plant resistance to M. oryzae and abolishes NIS and pinpoint glutamine as a potential key nutrient during NIS. PMID:28293247

  18. Yeast cell wall extract induces disease resistance against bacterial and fungal pathogens in Arabidopsis thaliana and Brassica crop.

    Directory of Open Access Journals (Sweden)

    Mari Narusaka

    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.

  19. Genetic differentiation and recombination among geographic populations of the fungal pathogen Colletotrichum truncatum from chili peppers in China

    OpenAIRE

    Diao, Yongzhao; Zhang, Can; Xu, Jianping; Lin, Dong; Liu, Li; Mtung'e, Olivo G; Liu, Xili

    2014-01-01

    Colletotrichum truncatum is an extremely important fungal pathogen. It can cause diseases both in humans and in over 460 plant species. However, little is known about its genetic diversity within and among populations. One of the major plant hosts of C. truncatum is pepper, and China is one of the main pepper-producing countries in the world. Here, we propose the hypotheses that geography has a major influence on the relationships among populations of C. truncatum in China and that infections...

  20. The Legitimate Name of a Fungal Plant Pathogen and the Ethics of Publication in the Era of Traceability.

    Science.gov (United States)

    Gonthier, Paolo; Visentin, Ivan; Valentino, Danila; Tamietti, Giacomo; Cardinale, Francesca

    2017-04-01

    When more scientists describe independently the same species under different valid Latin names, a case of synonymy occurs. In such a case, the international nomenclature rules stipulate that the first name to appear on a peer-reviewed publication has priority over the others. Based on a recent episode involving priority determination between two competing names of the same fungal plant pathogen, this letter wishes to open a discussion on the ethics of scientific publications and points out the necessity of a correct management of the information provided through personal communications, whose traceability would prevent their fraudulent or accidental manipulation.

  1. Secretome analysis identifies potential virulence factors of Diplodia corticola, a fungal pathogen involved in cork oak (Quercus suber) decline.

    Science.gov (United States)

    Fernandes, Isabel; Alves, Artur; Correia, António; Devreese, Bart; Esteves, Ana Cristina

    2014-01-01

    The characterisation of the secretome of phytopathogenic fungi may contribute to elucidate the molecular mechanisms of pathogenesis. This is particularly relevant for Diplodia corticola, a fungal plant pathogen belonging to the family Botryosphaeriaceae, whose genome remains unsequenced. This phytopathogenic fungus is recognised as one of the most important pathogens of cork oak, being related to the decline of cork oak forests in the Iberian Peninsula. Unfortunately, secretome analysis of filamentous fungi is limited by the low protein concentration and by the presence of many interfering substances, such as polysaccharides, which affect the separation and analysis by 1D and 2D gel electrophoresis. We compared six protein extraction protocols concerning their suitability for further application with proteomic workflows. The protocols involving protein precipitation were the most efficient, with emphasis on TCA-acetone protocol, allowing us to identify the most abundant proteins on the secretome of this plant pathogen. Approximately 60% of the spots detected were identified, all corresponding to extracellular proteins. Most proteins identified were carbohydrate degrading enzymes and proteases that may be related to D. corticola pathogenicity. Although the secretome was assessed in a noninfection environment, potential virulence factors such as the putative glucan-β-glucosidase, neuraminidase, and the putative ferulic acid esterase were identified. The data obtained forms a useful basis for a deeper understanding of the pathogenicity and infection biology of D. corticola. Moreover, it will contribute to the development of proteomics studies on other members of the Botryosphaeriaceae.

  2. Transcriptome analysis of the fungal pathogen Fusarium oxysporum f. sp. medicaginis during colonisation of resistant and susceptible Medicago truncatula hosts identifies differential pathogenicity profiles and novel candidate effectors.

    Science.gov (United States)

    Thatcher, Louise F; Williams, Angela H; Garg, Gagan; Buck, Sally-Anne G; Singh, Karam B

    2016-11-03

    Pathogenic members of the Fusarium oxysporum species complex are responsible for vascular wilt disease on many important crops including legumes, where they can be one of the most destructive disease causing necrotrophic fungi. We previously developed a model legume-infecting pathosystem based on the reference legume Medicago truncatula and a pathogenic F. oxysporum forma specialis (f. sp.) medicaginis (Fom). To dissect the molecular pathogenicity arsenal used by this root-infecting pathogen, we sequenced its transcriptome during infection of a susceptible and resistant host accession. High coverage RNA-Seq of Fom infected root samples harvested from susceptible (DZA315) or resistant (A17) M. truncatula seedlings at early or later stages of infection (2 or 7 days post infection (dpi)) and from vegetative (in vitro) samples facilitated the identification of unique and overlapping sets of in planta differentially expressed genes. This included enrichment, particularly in DZA315 in planta up-regulated datasets, for proteins associated with sugar, protein and plant cell wall metabolism, membrane transport, nutrient uptake and oxidative processes. Genes encoding effector-like proteins were identified, including homologues of the F. oxysporum f. sp. lycopersici Secreted In Xylem (SIX) proteins, and several novel candidate effectors based on predicted secretion, small protein size and high in-planta induced expression. The majority of the effector candidates contain no known protein domains but do share high similarity to predicted proteins predominantly from other F. oxysporum ff. spp. as well as other Fusaria (F. solani, F. fujikori, F. verticilloides, F. graminearum and F. pseudograminearum), and from another wilt pathogen of the same class, a Verticillium species. Overall, this suggests these novel effector candidates may play important roles in Fusaria and wilt pathogen virulence. Combining high coverage in planta RNA-Seq with knowledge of fungal pathogenicity

  3. Data set of Aspergillus flavus induced alterations in tear proteome: Understanding the pathogen-induced host response to fungal infection

    Directory of Open Access Journals (Sweden)

    Jeyalakshmi Kandhavelu

    2016-12-01

    Full Text Available Fungal keratitis is one of the leading causes of blindness in the tropical countries affecting individuals in their most productive age. The host immune response during this infection is poorly understood. We carried out comparative tear proteome analysis of Aspergillus flavus keratitis patients and uninfected controls. Proteome was separated into glycosylated and non-glycosylated fractions using lectin column chromatography before mass spectrometry. The data revealed the major processes activated in the human host in response to fungal infection and reflected in the tear. Extended analysis of this dataset presented here complements the research article entitled “Aspergillus flavus induced alterations in tear protein profile reveal pathogen-induced host response to fungal infection [1]” (Jeyalakhsmi Kandhavelu, Naveen Luke Demonte, Venkatesh Prajna Namperumalsamy, Lalitha Prajna, Chitra Thangavel, Jeya Maheshwari Jayapal, Dharmalingam Kuppamuthu, 2016. The mass spectrometry proteomics data have been deposited in the ProteomeXchange Consortium via the PRIDE partner repository with the dataset identifier PRIDE:PXD003825.

  4. A link between virulence and homeostatic responses to hypoxia during infection by the human fungal pathogen Cryptococcus neoformans.

    Directory of Open Access Journals (Sweden)

    Cheryl D Chun

    2007-02-01

    Full Text Available Fungal pathogens of humans require molecular oxygen for several essential biochemical reactions, yet virtually nothing is known about how they adapt to the relatively hypoxic environment of infected tissues. We isolated mutants defective in growth under hypoxic conditions, but normal for growth in normoxic conditions, in Cryptococcus neoformans, the most common cause of fungal meningitis. Two regulatory pathways were identified: one homologous to the mammalian sterol-response element binding protein (SREBP cholesterol biosynthesis regulatory pathway, and the other a two-component-like pathway involving a fungal-specific hybrid histidine kinase family member, Tco1. We show that cleavage of the SREBP precursor homolog Sre1-which is predicted to release its DNA-binding domain from the membrane-occurs in response to hypoxia, and that Sre1 is required for hypoxic induction of genes encoding for oxygen-dependent enzymes involved in ergosterol synthesis. Importantly, mutants in either the SREBP pathway or the Tco1 pathway display defects in their ability to proliferate in host tissues and to cause disease in infected mice, linking for the first time to our knowledge hypoxic adaptation and pathogenesis by a eukaryotic aerobe. SREBP pathway mutants were found to be a hundred times more sensitive than wild-type to fluconazole, a widely used antifungal agent that inhibits ergosterol synthesis, suggesting that inhibitors of SREBP processing could substantially enhance the potency of current therapies.

  5. [Fungal keratitis].

    Science.gov (United States)

    Bourcier, T; Sauer, A; Letscher-Bru, V; Candolfi, E

    2011-10-01

    Fungal keratitis (keratomycosis) is a rare but severe cause of infectious keratitis. Its incidence is constant, due to steroids or immunosuppressive treatments and contact lenses. Pathogens often invade corneas with chronic diseases of the ocular surface but fungal keratitis is also observed following injuries with plant foreign objects. The poor prognosis of these infections is related both to fungal virulence, decreased host defense, as well as delays in diagnosis. However, new antimycotic treatments allow better management and prognosis.

  6. Breakage-fusion-bridge cycles and large insertions contribute to the rapid evolution of accessory chromosomes in a fungal pathogen.

    Directory of Open Access Journals (Sweden)

    Daniel Croll

    2013-06-01

    Full Text Available Chromosomal rearrangements are a major driver of eukaryotic genome evolution, affecting speciation, pathogenicity and cancer progression. Changes in chromosome structure are often initiated by mis-repair of double-strand breaks in the DNA. Mis-repair is particularly likely when telomeres are lost or when dispersed repeats misalign during crossing-over. Fungi carry highly polymorphic chromosomal complements showing substantial variation in chromosome length and number. The mechanisms driving chromosome polymorphism in fungi are poorly understood. We aimed to identify mechanisms of chromosomal rearrangements in the fungal wheat pathogen Zymoseptoria tritici. We combined population genomic resequencing and chromosomal segment PCR assays with electrophoretic karyotyping and resequencing of parents and offspring from experimental crosses to show that this pathogen harbors a highly diverse complement of accessory chromosomes that exhibits strong global geographic differentiation in numbers and lengths of chromosomes. Homologous chromosomes carried highly differentiated gene contents due to numerous insertions and deletions. The largest accessory chromosome recently doubled in length through insertions totaling 380 kb. Based on comparative genomics, we identified the precise breakpoint locations of these insertions. Nondisjunction during meiosis led to chromosome losses in progeny of three different crosses. We showed that a new accessory chromosome emerged in two viable offspring through a fusion between sister chromatids. Such chromosome fusion is likely to initiate a breakage-fusion-bridge (BFB cycle that can rapidly degenerate chromosomal structure. We suggest that the accessory chromosomes of Z. tritici originated mainly from ancient core chromosomes through a degeneration process that included BFB cycles, nondisjunction and mutational decay of duplicated sequences. The rapidly evolving accessory chromosome complement may serve as a cradle for

  7. Breakage-fusion-bridge cycles and large insertions contribute to the rapid evolution of accessory chromosomes in a fungal pathogen.

    Science.gov (United States)

    Croll, Daniel; Zala, Marcello; McDonald, Bruce A

    2013-06-01

    Chromosomal rearrangements are a major driver of eukaryotic genome evolution, affecting speciation, pathogenicity and cancer progression. Changes in chromosome structure are often initiated by mis-repair of double-strand breaks in the DNA. Mis-repair is particularly likely when telomeres are lost or when dispersed repeats misalign during crossing-over. Fungi carry highly polymorphic chromosomal complements showing substantial variation in chromosome length and number. The mechanisms driving chromosome polymorphism in fungi are poorly understood. We aimed to identify mechanisms of chromosomal rearrangements in the fungal wheat pathogen Zymoseptoria tritici. We combined population genomic resequencing and chromosomal segment PCR assays with electrophoretic karyotyping and resequencing of parents and offspring from experimental crosses to show that this pathogen harbors a highly diverse complement of accessory chromosomes that exhibits strong global geographic differentiation in numbers and lengths of chromosomes. Homologous chromosomes carried highly differentiated gene contents due to numerous insertions and deletions. The largest accessory chromosome recently doubled in length through insertions totaling 380 kb. Based on comparative genomics, we identified the precise breakpoint locations of these insertions. Nondisjunction during meiosis led to chromosome losses in progeny of three different crosses. We showed that a new accessory chromosome emerged in two viable offspring through a fusion between sister chromatids. Such chromosome fusion is likely to initiate a breakage-fusion-bridge (BFB) cycle that can rapidly degenerate chromosomal structure. We suggest that the accessory chromosomes of Z. tritici originated mainly from ancient core chromosomes through a degeneration process that included BFB cycles, nondisjunction and mutational decay of duplicated sequences. The rapidly evolving accessory chromosome complement may serve as a cradle for adaptive evolution in

  8. Fungal-specific transcription factor AbPf2 activates pathogenicity in Alternaria brassicicola

    Energy Technology Data Exchange (ETDEWEB)

    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

    2013-05-24

    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.

  9. Tenebrionid secretions and a fungal benzoquinone oxidoreductase form competing components of an arms race between a host and pathogen.

    Science.gov (United States)

    Pedrini, Nicolás; Ortiz-Urquiza, Almudena; Huarte-Bonnet, Carla; Fan, Yanhua; Juárez, M Patricia; Keyhani, Nemat O

    2015-07-14

    Entomopathogenic fungi and their insect hosts represent a model system for examining invertebrate-pathogen coevolutionary selection processes. Here we report the characterization of competing components of an arms race consisting of insect protective antimicrobial compounds and evolving fungal mechanisms of detoxification. The insect pathogenic fungus Beauveria bassiana has a remarkably wide host range; however, some insects are resistant to fungal infection. Among resistant insects is the tenebrionid beetle Tribolium castaneum that produces benzoquinone-containing defensive secretions. Reduced fungal germination and growth was seen in media containing T. castaneum dichloromethane extracts or synthetic benzoquinone. In response to benzoquinone exposure, the fungus expresses a 1,4-benzoquinone oxidoreductase, BbbqrA, induced >40-fold. Gene knockout mutants (ΔBbbqrA) showed increased growth inhibition, whereas B. bassiana overexpressing BbbqrA (Bb::BbbqrA(O)) displayed increased resistance to benzoquinone compared with wild type. Increased benzoquinone reductase activity was detected in wild-type cells exposed to benzoquinone and in the overexpression strain. Heterologous expression and purification of BbBqrA in Escherichia coli confirmed NAD(P)H-dependent benzoquinone reductase activity. The ΔBbbqrA strain showed decreased virulence toward T. castaneum, whereas overexpression of BbbqrA increased mortality versus T. castaneum. No change in virulence was seen for the ΔBbbqrA or Bb::BbbqrA(O) strains when tested against the greater wax moth Galleria mellonella or the beetle Sitophilus oryzae, neither of which produce significant amounts of cuticular quinones. The observation that artificial overexpression of BbbqrA results in increased virulence only toward quinone-secreting insects implies the lack of strong selection or current failure of B. bassiana to counteradapt to this particular host defense throughout evolution.

  10. Fungal pathogen complexes associated with rambutan, longan and mango diseases in Puerto Rico

    Science.gov (United States)

    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...

  11. Ancient dispersal of the human fungal pathogen Cryptococcus gattii from the Amazon rainforest.

    NARCIS (Netherlands)

    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.

    2013-01-01

    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

  12. Pathogenic Yet Environmentally Friendly? Black Fungal Candidates for Bioremediation of Pollutants : Geomicrobiology Journal

    NARCIS (Netherlands)

    Blasi, B.; Poyntner, C.; Rudavsky, T.; Prenafeta-Boldu, F. X.; De Hoog, S.; Tafer, H.; Sterflinger, K.

    2016-01-01

    A collection of 163 strains of black yeast-like fungi from the CBS Fungal Biodiversity Center (Utrecht, The Netherlands), has been screened for the ability to grow on hexadecane, toluene and polychlorinated biphenyl 126 (PCB126) as the sole carbon and energy source. These compounds were chosen as re

  13. Importance of resolving fungal nomenclature: the case of multiple pathogenic species in the Cryptococcus genus

    Science.gov (United States)

    Cryptococcosis is a major fungal disease caused by members of the Cryptococcus gattii and Cryptococcus neoformans species complexes. After more than 15 years of molecular genetic and phenotypic studies and much debate, a proposal for a taxonomic revision was made. The two varieties within C. neoform...

  14. Impacts of fungal stalk rot pathogens on physicochemical properties of sorghum grain

    Science.gov (United States)

    Stalk rot diseases are among the most ubiquitous and damaging fungal diseases of sorghum worldwide. Although reports of quantitative stalk rot yield losses are available, the impact of stalk rot on the physicochemical attributes of sorghum grain is currently unknown. This study was conducted to test...

  15. Chemo-sensitization of fungal pathogens to antimicrobial agents using benzaldehyde analogs

    Science.gov (United States)

    Activity of conventional antifungal agents, fludioxonil, strobilurin and antimycinA, which target the oxidative and osmotic stress response systems, was elevated by co-application of certain analogs of benzaldehyde. Fungal tolerance to 2,3-dihydroxybenzaldehyde or 2,3-dihydroxybenzoic acid was foun...

  16. Ancient dispersal of the human fungal pathogen Cryptococcus gattii from the Amazon rainforest

    NARCIS (Netherlands)

    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.

    2013-01-01

    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 o

  17. Ancient Dispersal of the Human Fungal Pathogen Cryptococcus gattii from the Amazon Rainforest

    NARCIS (Netherlands)

    Hagen, Ferry; Ceresini, Paulo C.; Polacheck, Itzhack; Ma, Hansong; van Nieuwerburgh, Filip; Gabaldon, 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.; Castaneda, Elizabeth; Lazera, Marcia; Meyer, Wieland; Deforce, Dieter; Meis, Jacques F.; May, Robin C.; Klaassen, Corne H. W.; Boekhout, Teun

    2013-01-01

    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 o

  18. The FRP1 F-box gene has different functions in sexuality, pathogenicity and metabolism in three fungal pathogens

    NARCIS (Netherlands)

    Jonkers, W.; van Kan, J.A.L.; Tijm, P.; Lee, Y.-W.; Tudzynski, P.; Rep, M.; Michielse, C.B.

    2011-01-01

    Plant-pathogenic fungi employ a variety of infection strategies; as a result, fungi probably rely on different sets of proteins for successful infection. The F-box protein Frp1, only present in filamentous fungi belonging to the Sordariomycetes, Leotiomycetes and Dothideomycetes, is required for

  19. Autophagy provides nutrients for nonassimilating fungal structures and is necessary for plant colonization but not for infection in the necrotrophic plant pathogen Fusarium graminearum

    DEFF Research Database (Denmark)

    Josefsen, Lone; Droce, Aida; Søndergaard, Teis

    2012-01-01

    The role of autophagy in necrotrophic fungal physiology and infection biology is poorly understood. We have studied autophagy in the necrotrophic plant pathogen Fusarium graminearum in relation to development of nonassimilating structures and infection. We identified an ATG8 homolog F. graminearum...... a pivotal role for supplying nutrients to nonassimilating structures necessary for growth and is important for plant colonization. This also indicates that autophagy is a central mechanism for fungal adaptation to nonoptimal C/N ratios....

  20. Effects of temperature during soybean seed development on defense-related gene expression and fungal pathogen accumulation.

    Science.gov (United States)

    Upchurch, Robert G; Ramirez, Martha E

    2011-12-01

    Soybean [Glycine max (L.) Merr] plants were exposed to three temperature regimens during seed development to investigate the effect of temperature on the expression of eight defense-related genes and the accumulation of two fungal pathogens in inoculated seeds. In seeds prior to inoculation, either a day/night warm (34/26 °C) or a cool temperature (22/18 °C) relative to normal (26/22 °C) resulted in altered patterns of gene expression including substantially lower expression of PR1, PR3 and PR10. After seed inoculation with Cercospora kikuchii, pathogen accumulation was lowest in seeds produced at 22/18 °C in which of all defense genes, MMP2 was uniquely most highly induced. For seeds inoculated with Diaporthe phaseolorum, pathogen accumulation was lowest in seeds produced at 34/26 °C in which of all defense genes, PR10 was uniquely most highly induced. Our detached seed assays clearly demonstrated that the temperature regimens we applied during seed development produced significant changes in seed defense-related gene expression both pre- and post inoculation and our findings support the hypothesis that global climate change may alter plant-pathogen interactions and thereby potentially crop productivity.

  1. Reduced immune function predicts disease susceptibility in frogs infected with a deadly fungal pathogen

    National Research Council Canada - National Science Library

    Savage, Anna E; Terrell, Kimberly A; Gratwicke, Brian; Mattheus, Nichole M; Augustine, Lauren; Fleischer, Robert C

    2016-01-01

    The relationship between amphibian immune function and disease susceptibility is of primary concern given current worldwide declines linked to the pathogenic fungus Batrachochytrium dendrobatidis (Bd...

  2. Identification and functional characterization of proteases and protease inhibitors involved in virulence of fungal tomato pathogens

    NARCIS (Netherlands)

    Karimi Jashni, M.

    2015-01-01

    Pathogens cause disease on both animal and plant hosts. For successful infection and establishment of disease, pathogens need proper weaponry to protect themselves against host defenses and to promote host colonization to facilitate uptake of nutrients for growth and reproduction. Indeed, plant

  3. Role of hydrogen peroxide during the interaction between the hemibiotrophic fungal pathogen Septoria tritici and wheat

    NARCIS (Netherlands)

    Shetty, N.P.; Mehrabi, R.; Lütken, H.; Haldrup, A.; Kema, G.H.J.

    2007-01-01

    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, inf

  4. Fungal naphtho-γ-pyrones: Potent antibiotics for drug-resistant microbial pathogens

    OpenAIRE

    Yan He; Jun Tian; Xintao Chen; Weiguang Sun; Hucheng Zhu; Qin Li; Liang Lei; Guangmin Yao; Yongbo Xue; Jianping Wang; Hua Li; Yonghui Zhang

    2016-01-01

    Four naphtho-γ-pyrones (fonsecinones A and C and aurasperones A and E) were identified as potential antibacterial agents against Escherichia coli, extended-spectrum β-lactamase (ESBL)-producing E. coli, Pseudomonas aeruginosa, Enterococcus faecalis, and methicillin-resistant Staphylococcus aureus (MRSA) in an in vitro antibacterial screen of 218 fungal metabolites. Fonsecinone A (2) exhibited the most potent antibacterial activity, with minimum inhibitory concentrations (MICs) of 4.26, 17.04,...

  5. The Genome Sequence of the Fungal Pathogen Fusarium virguliforme That Causes Sudden Death Syndrome in Soybean

    Science.gov (United States)

    Srivastava, Subodh K.; Huang, Xiaoqiu; Brar, Hargeet K.; Fakhoury, Ahmad M.; Bluhm, Burton H.; Bhattacharyya, Madan K.

    2014-01-01

    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. Methodology/Principal Findings 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. Conclusions 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

  6. The anti-biofilm potential of pomegranate (Punica granatum L.) extract against human bacterial and fungal pathogens.

    Science.gov (United States)

    Bakkiyaraj, Dhamodharan; Nandhini, Janarthanam Rathna; Malathy, Balakumar; Pandian, Shunmugiah Karutha

    2013-09-01

    Infectious diseases caused by bacteria and fungi are the major cause of morbidity and mortality across the globe. Multi-drug resistance in these pathogens augments the complexity and severity of the diseases. Various studies have shown the role of biofilms in multi-drug resistance, where the pathogen resides inside a protective coat made of extracellular polymeric substances. Since biofilms directly influence the virulence and pathogenicity of a pathogen, it is optimal to employ a strategy that effectively inhibits the formation of biofilm. Pomegranate is a common food and is also used traditionally to treat various ailments. This study assessed the anti-biofilm activity of a methanolic extract of pomegranate against bacterial and fungal pathogens. Methanolic extract of pomegranate was shown to inhibit the formation of biofilms by Staphylococcus aureus, methicillin resistant S. aureus, Escherichia coli, and Candida albicans. Apart from inhibiting the formation of biofilm, pomegranate extract disrupted pre-formed biofilms and inhibited germ tube formation, a virulence trait, in C. albicans. Characterization of the methanolic extract of pomegranate revealed the presence of ellagic acid (2,3,7,8-tetrahydroxy-chromeno[5,4,3-cde]chromene-5,10-dione) as the major component. Ellagic acid is a bioactive tannin known for its antioxidant, anticancer, and anti-inflammatory properties. Further studies revealed the ability of ellagic acid to inhibit the growth of all species in suspension at higher concentrations (>75 μg ml(-1)) and biofilm formation at lower concentrations (pomegranate for the treatment of human ailments.

  7. Insight into trade-off between wood decay and parasitism from the genome of a fungal forest pathogen

    Energy Technology Data Exchange (ETDEWEB)

    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

    2012-01-01

    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.

  8. Impacts of thiamethoxam seed treatment and host plant resistance on the soybean aphid fungal pathogen, Pandora neoaphidis.

    Science.gov (United States)

    Koch, Karrie A; Ragsdale, David W

    2011-12-01

    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.

  9. A novel role for the NLRC4 inflammasome in mucosal defenses against the fungal pathogen Candida albicans.

    Directory of Open Access Journals (Sweden)

    Jeffrey Tomalka

    2011-12-01

    Full Text Available Candida sp. are opportunistic fungal pathogens that colonize the skin and oral cavity and, when overgrown under permissive conditions, cause inflammation and disease. Previously, we identified a central role for the NLRP3 inflammasome in regulating IL-1β production and resistance to dissemination from oral infection with Candida albicans. Here we show that mucosal expression of NLRP3 and NLRC4 is induced by Candida infection, and up-regulation of these molecules is impaired in NLRP3 and NLRC4 deficient mice. Additionally, we reveal a role for the NLRC4 inflammasome in anti-fungal defenses. NLRC4 is important for control of mucosal Candida infection and impacts inflammatory cell recruitment to infected tissues, as well as protects against systemic dissemination of infection. Deficiency in either NLRC4 or NLRP3 results in severely attenuated pro-inflammatory and antimicrobial peptide responses in the oral cavity. Using bone marrow chimeric mouse models, we show that, in contrast to NLRP3 which limits the severity of infection when present in either the hematopoietic or stromal compartments, NLRC4 plays an important role in limiting mucosal candidiasis when functioning at the level of the mucosal stroma. Collectively, these studies reveal the tissue specific roles of the NLRP3 and NLRC4 inflammasome in innate immune responses against mucosal Candida infection.

  10. Identification of volatile compounds produced by the bacterium Burkholderia tropica that inhibit the growth of fungal pathogens

    Science.gov (United States)

    Tenorio-Salgado, Silvia; Tinoco, Raunel; Vazquez-Duhalt, Rafael; Caballero-Mellado, Jesus; Perez-Rueda, Ernesto

    2013-01-01

    It has been documented that bacteria from the Burkholderia genera produce different kinds of compounds that inhibit plant pathogens, however in Burkholderia tropica, an endophytic diazotrophic and phosphate-solubilizing bacterium isolated from a wide diversity of plants, the capacity to produce antifungal compounds has not been evaluated. In order to expand our knowledge about Burkholderia tropica as a potential biological control agent, we analyzed 15 different strains of this bacterium to evaluate their capacities to inhibit the growth of four phytopathogenic fungi, Colletotrichum gloeosporioides, Fusarium culmorum, Fusarium oxysporum and Sclerotium rolffsi. Diverse analytical techniques, including plant root protection and dish plate growth assays and gas chromatography-mass spectroscopy showed that the fungal growth inhibition was intimately associated with the volatile compounds produced by B. tropica and, in particular, two bacterial strains (MTo293 and TTe203) exhibited the highest radial mycelial growth inhibition. Morphological changes associated with these compounds, such as disruption of fungal hyphae, were identified by using photomicrographic analysis. By using gas chromatography-mass spectroscopy technique, 18 volatile compounds involved in the growth inhibition mechanism were identified, including α-pinene and limonene. In addition, we found a high proportion of bacterial strains that produced siderophores during growth with different carbon sources, such as alanine and glutamic acid; however, their roles in the antagonism mechanism remain unclear. PMID:23680857

  11. Phylogenetic distribution of symbiotic bacteria from Panamanian amphibians that inhibit growth of the lethal fungal pathogen Batrachochytrium dendrobatidis.

    Science.gov (United States)

    Becker, Matthew H; Walke, Jenifer B; Murrill, Lindsey; Woodhams, Douglas C; Reinert, Laura K; Rollins-Smith, Louise A; Burzynski, Elizabeth A; Umile, Thomas P; Minbiole, Kevin P C; Belden, Lisa K

    2015-04-01

    The introduction of next-generation sequencing has allowed for greater understanding of community composition of symbiotic microbial communities. However, determining the function of individual members of these microbial communities still largely relies on culture-based methods. Here, we present results on the phylogenetic distribution of a defensive functional trait of cultured symbiotic bacteria associated with amphibians. Amphibians are host to a diverse community of cutaneous bacteria and some of these bacteria protect their host from the lethal fungal pathogen Batrachochytrium dendrobatidis (Bd) by secreting antifungal metabolites. We cultured over 450 bacterial isolates from the skins of Panamanian amphibian species and tested their interactions with Bd using an in vitro challenge assay. For a subset of isolates, we also completed coculture experiments and found that culturing isolates with Bd had no effect on inhibitory properties of the bacteria, but it significantly decreased metabolite secretion. In challenge assays, approximately 75% of the bacterial isolates inhibited Bd to some extent and these inhibitory isolates were widely distributed among all bacterial phyla. Although there was no clear phylogenetic signal of inhibition, three genera, Stenotrophomonas, Aeromonas and Pseudomonas, had a high proportion of inhibitory isolates (100%, 77% and 73%, respectively). Overall, our results demonstrate that antifungal properties are phylogenetically widespread in symbiotic microbial communities of Panamanian amphibians and that some functional redundancy for fungal inhibition occurs in these communities. We hope that these findings contribute to the discovery and development of probiotics for amphibians that can mitigate the threat of chytridiomycosis. © 2015 John Wiley & Sons Ltd.

  12. Memory CD4+ T cells are required for optimal NK cell effector functions against the opportunistic fungal pathogen Pneumocystis murina.

    Science.gov (United States)

    Kelly, Michelle N; Zheng, Mingquan; Ruan, Sanbao; Kolls, Jay; D'Souza, Alain; Shellito, Judd E

    2013-01-01

    Little is known about the role of NK cells or their interplay with other immune cells during opportunistic infections. Using our murine model of Pneumocystis pneumonia, we found that loss of NK cells during immunosuppression results in substantial Pneumocystis lung burden. During early infection of C57B/6 CD4(+) T cell-depleted mice, there were significantly fewer NK cells in the lung tissue compared with CD4(+) T cell-intact animals, and the NK cells present demonstrated decreased upregulation of the activation marker NKp46 and production of the effector cytokine, IFN-γ. Furthermore, coincubation studies revealed a significant increase in fungal killing when NK cells were combined with CD4(+) T cells compared with either cell alone, which was coincident with a significant increase in perforin production by NK cells. Finally, however, we found through adoptive transfer that memory CD4(+) T cells are required for significant NK cell upregulation of the activation marker NK group 2D and production of IFN-γ, granzyme B, and perforin during Pneumocystis infection. To the best of our knowledge, this study is the first to demonstrate a role for NK cells in immunity to Pneumocystis pneumonia, as well as to establish a functional relationship between CD4(+) T cells and NK cells in the host response to an opportunistic fungal pathogen.

  13. Chenopodolin: a phytotoxic unrearranged ent-pimaradiene diterpene produced by Phoma chenopodicola, a fungal pathogen for Chenopodium album biocontrol.

    Science.gov (United States)

    Cimmino, Alessio; Andolfi, Anna; Zonno, Maria C; Avolio, Fabiana; Santini, Antonello; Tuzi, Angela; Berestetskyi, Alexander; Vurro, Maurizio; Evidente, Antonio

    2013-07-26

    A new phytotoxic unrearranged ent-pimaradiene diterpene, named chenopodolin, was isolated from the liquid culture of Phoma chenopodicola, a fungal pathogen proposed for the biological control of Chenopodium album, a common worldwide weed of arable crops such as sugar beet and maize. The structure of chenopodolin was established by spectroscopic, X-ray, and chemical methods as (1S,2S,3S,4S,5S,9R,10S,12S,13S)-1,12-acetoxy-2,3-hydroxy-6-oxopimara-7(8),15-dien-18-oic acid 2,18-lactone. At a concentration of 2 mg/mL, the toxin caused necrotic lesions on Mercurialis annua, Cirsium arvense, and Setaria viride. Five derivatives were prepared by chemical modification of chenopodolin functionalities, and some structure-activity relationships are discussed.

  14. Insights from the genome of the biotrophic fungal plant pathogen Ustilago maydis.

    Science.gov (United States)

    Kämper, Jörg; Kahmann, Regine; Bölker, Michael; Ma, Li-Jun; Brefort, Thomas; Saville, Barry J; Banuett, Flora; Kronstad, James W; Gold, Scott E; Müller, Olaf; Perlin, Michael H; Wösten, Han A B; de Vries, Ronald; Ruiz-Herrera, José; Reynaga-Peña, Cristina G; Snetselaar, Karen; McCann, Michael; Pérez-Martín, José; Feldbrügge, Michael; Basse, Christoph W; Steinberg, Gero; Ibeas, Jose I; Holloman, William; Guzman, Plinio; Farman, Mark; Stajich, Jason E; Sentandreu, Rafael; González-Prieto, Juan M; Kennell, John C; Molina, Lazaro; Schirawski, Jan; Mendoza-Mendoza, Artemio; Greilinger, Doris; Münch, Karin; Rössel, Nicole; Scherer, Mario; Vranes, Miroslav; Ladendorf, Oliver; Vincon, Volker; Fuchs, Uta; Sandrock, Björn; Meng, Shaowu; Ho, Eric C H; Cahill, Matt J; Boyce, Kylie J; Klose, Jana; Klosterman, Steven J; Deelstra, Heine J; Ortiz-Castellanos, Lucila; Li, Weixi; Sanchez-Alonso, Patricia; Schreier, Peter H; Häuser-Hahn, Isolde; Vaupel, Martin; Koopmann, Edda; Friedrich, Gabi; Voss, Hartmut; Schlüter, Thomas; Margolis, Jonathan; Platt, Darren; Swimmer, Candace; Gnirke, Andreas; Chen, Feng; Vysotskaia, Valentina; Mannhaupt, Gertrud; Güldener, Ulrich; Münsterkötter, Martin; Haase, Dirk; Oesterheld, Matthias; Mewes, Hans-Werner; Mauceli, Evan W; DeCaprio, David; Wade, Claire M; Butler, Jonathan; Young, Sarah; Jaffe, David B; Calvo, Sarah; Nusbaum, Chad; Galagan, James; Birren, Bruce W

    2006-11-02

    Ustilago maydis is a ubiquitous pathogen of maize and a well-established model organism for the study of plant-microbe interactions. This basidiomycete fungus does not use aggressive virulence strategies to kill its host. U. maydis belongs to the group of biotrophic parasites (the smuts) that depend on living tissue for proliferation and development. Here we report the genome sequence for a member of this economically important group of biotrophic fungi. The 20.5-million-base U. maydis genome assembly contains 6,902 predicted protein-encoding genes and lacks pathogenicity signatures found in the genomes of aggressive pathogenic fungi, for example a battery of cell-wall-degrading enzymes. However, we detected unexpected genomic features responsible for the pathogenicity of this organism. Specifically, we found 12 clusters of genes encoding small secreted proteins with unknown function. A significant fraction of these genes exists in small gene families. Expression analysis showed that most of the genes contained in these clusters are regulated together and induced in infected tissue. Deletion of individual clusters altered the virulence of U. maydis in five cases, ranging from a complete lack of symptoms to hypervirulence. Despite years of research into the mechanism of pathogenicity in U. maydis, no 'true' virulence factors had been previously identified. Thus, the discovery of the secreted protein gene clusters and the functional demonstration of their decisive role in the infection process illuminate previously unknown mechanisms of pathogenicity operating in biotrophic fungi. Genomic analysis is, similarly, likely to open up new avenues for the discovery of virulence determinants in other pathogens.

  15. Bacterial antagonists of fungal pathogens also control root-knot nematodes by induced systemic resistance of tomato plants.

    Science.gov (United States)

    Adam, Mohamed; Heuer, Holger; Hallmann, Johannes

    2014-01-01

    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.

  16. Common protein sequence signatures associate with Sclerotinia borealis lifestyle and secretion in fungal pathogens of the Sclerotiniaceae

    Directory of Open Access Journals (Sweden)

    Thomas eBadet

    2015-09-01

    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.

  17. The Black Yeast Exophiala dermatitidis and Other Selected Opportunistic Human Fungal Pathogens Spread from Dishwashers to Kitchens.

    Directory of Open Access Journals (Sweden)

    Jerneja Zupančič

    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

  18. The Black Yeast Exophiala dermatitidis and Other Selected Opportunistic Human Fungal Pathogens Spread from Dishwashers to Kitchens.

    Science.gov (United States)

    Zupančič, Jerneja; Novak Babič, Monika; Zalar, Polona; Gunde-Cimerman, Nina

    2016-01-01

    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 dishwashers. We

  19. Bacterial antagonists of fungal pathogens also control root-knot nematodes by induced systemic resistance of tomato plants.

    Directory of Open Access Journals (Sweden)

    Mohamed Adam

    Full Text Available 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.

  20. Fungal Zinc Homeostasis - A Tug of War Between the Pathogen and Host.

    Science.gov (United States)

    Walencik, Paulina K; Watly, Joanna; Rowinska-Zyrek, Magdalena

    2016-01-01

    In the last decade, drug resistant invasive mycoses have become significantly more common and new antifungal drugs and ways to specifically deliver them to the fungal cell are being looked for. One of the biggest obstacles in finding such comes from the fact that fungi share essential metabolic pathways with humans. One significant difference in the metabolism of those two cells that can be challenged when looking for possible selective therapeutics is the uptake of zinc, a nutrient crucial for the fungal survival and virulence. This work summarizes the recent advances in the biological inorganic chemistry of zinc metabolism in fungi. The regulation of zinc uptake, various types of its transmembrane transport, storage and the maintenance of intracellular zinc homeostasis is discussed in detail, with a special focus on the concept of a constant 'tug of war' over zinc between the fungus and its host, with the host trying to withhold essential Zn(II), and the fungus counteracting by producing high-affinity zinc binding molecules.

  1. Evidence for synergistic activity of plant-derived essential oils against fungal pathogens of food.

    Science.gov (United States)

    Hossain, Farah; Follett, Peter; Dang Vu, Khang; Harich, Mehdi; Salmieri, Stephane; Lacroix, Monique

    2016-02-01

    The antifungal activities of eight essential oils (EOs) namely basil, cinnamon, eucalyptus, mandarin, oregano, peppermint, tea tree and thyme were evaluated for their ability to inhibit growth of Aspergillus niger, Aspergillus flavus, Aspergillus parasiticus and Penicillium chrysogenum. The antifungal activity of the EOs was assessed by the minimum inhibitory concentration (MIC) using 96-well microplate analysis. The interactions between different EO combinations were done by the checkerboard technique. The highest antifungal activity was exhibited by oregano and thyme which showed lower MIC values amongst all the tested fungi. The antifungal activity of the other EOs could be appropriately ranked in a descending sequence of cinnamon, peppermint, tea tree and basil. Eucalyptus and mandarin showed the least efficiency as they could not inhibit any of the fungal growth at 10,000 ppm. The interaction between these two EOs also showed no interaction on the tested species. A combined formulation of oregano and thyme resulted in a synergistic effect, showing enhanced efficiency against A. flavus and A. parasiticus and P. chrysogenum. Mixtures of peppermint and tea tree produced synergistic effect against A. niger. Application of a modified Gompertz model considering fungal growth parameters like maximum colony diameter, maximum growth rate and lag time periods, under the various EO treatment scenarios, showed that the model could adequately describe and predict the growth of the tested fungi under these conditions.

  2. Schizophyllum commune as an emerging fungal pathogen: a review and report of two cases.

    Science.gov (United States)

    Chowdhary, A; Randhawa, H S; Gaur, S N; Agarwal, K; Kathuria, S; Roy, P; Klaassen, C H; Meis, J F

    2013-01-01

    We report Schizophyllum commune as the aetiological agent of one case each of allergic broncho-pulmonary mycosis (ABPM) and pulmonary fungal ball, and present a literature review. The fungus was characterised by clamp connections, hyphal spicules, and formation of basidiocarps with basidiospores. The phenotypic identification was confirmed by sequencing of the ITS region. To-date, ABPM and pulmonary fungal ball to S. commune have been reported exclusively from Japan and North America respectively. Of the 71 globally reported cases due to S. commune, 45 (63%) were bronchopulmonary, 22 (31%) sinusitis and 4 extrapulmonary. Taken together, cases of bronchopulmonary disease and sinusitis numbered 67 (94%), indicating the respiratory tract as the primary target of disease. Concerning the country-wise distribution, Japan topped the list with 33 cases (46%), followed by Iran - 7 cases (10%), U.S.A. - 6 cases (9%), and a lower prevalence of 1.4-6% for the remaining 12 countries. The preponderance of the disease in Japan may be attributed to its greater awareness vis-à-vis that in other countries rather than to any geographical/climatic factors. We believe that the burden of S. commune-incited disease is currently underestimated, warranting comprehensive prospective studies to determine its prevalence. © 2012 Blackwell Verlag GmbH.

  3. Pulsed light for the inactivation of fungal biofilms of clinically important pathogenic Candida species.

    Science.gov (United States)

    Garvey, Mary; Andrade Fernandes, Joao Paulo; Rowan, Neil

    2015-07-01

    Microorganisms are naturally found as biofilm communities more than planktonic free-floating cells; however, planktonic culture remains the current model for microbiological studies, such as disinfection techniques. The presence of fungal biofilms in the clinical setting has a negative impact on patient mortality, as Candida biofilms have proved to be resistant to biocides in numerous in vitro studies; however, there is limited information on the effect of pulsed light on sessile communities. Here we report on the use of pulsed UV light for the effective inactivation of clinically relevant Candida species. Fungal biofilms were grown by use of a CDC reactor on clinically relevant surfaces. Following a maximal 72 h formation period, the densely populated biofilms were exposed to pulsed light at varying fluences to determine biofilm sensitivity to pulsed-light inactivation. The results were then compared to planktonic cell inactivation. High levels of inactivation of C. albicans and C. parapsilosis biofilms were achieved with pulsed light for both 48 and 72 h biofilm structures. The findings suggest that pulsed light has the potential to provide a means of surface decontamination, subsequently reducing the risk of infection to patients. The research described herein deals with an important aspect of disease prevention and public health.

  4. Fungal volatiles: an environmentally friendly tool to control pathogenic microorganisms in plants.

    Science.gov (United States)

    Schalchli, H; Tortella, G R; Rubilar, O; Parra, L; Hormazabal, E; Quiroz, A

    2016-01-01

    Fungi are an extraordinary and immensely diverse group of microorganisms that colonize many habitats even competing with other microorganisms. Fungi have received recognition for interesting metabolic activities that have an enormous variety of biotechnological applications. Previously, volatile organic compounds produced by fungi (FVOCs) have been demonstrated to have a great capacity for use as antagonist products against plant pathogens. However, in recent years, FVOCs have been received attention as potential alternatives to the use of traditional pesticides and, therefore, as important eco-friendly biotechnological tools to control plant pathogens. Therefore, highlighting the current state of knowledge of these fascinating FVOCs, the actual detection techniques and the bioactivity against plant pathogens is essential to the discovery of new products that can be used as biopesticides.

  5. Genes expressed in grapevine leaves reveal latent wood infection by the fungal pathogen Neofusicoccum parvum.

    Directory of Open Access Journals (Sweden)

    Stefan Czemmel

    Full Text Available Some pathogenic species of the Botryosphaeriaceae have a latent phase, colonizing woody tissues while perennial hosts show no apparent symptoms until conditions for disease development become favorable. Detection of these pathogens is often limited to the later pathogenic phase. The latent phase is poorly characterized, despite the need for non-destructive detection tools and effective quarantine strategies, which would benefit from identification of host-based markers in leaves. Neofusicoccum parvum infects the wood of grapevines and other horticultural crops, killing the fruit-bearing shoots. We used light microscopy and high-resolution computed tomography (HRCT to examine the spatio-temporal relationship between pathogen colonization and anatomical changes in stem sections. To identify differentially-expressed grape genes, leaves from inoculated and non-inoculated plants were examined using RNA-Seq. The latent phase occurred between 0 and 1.5 months post-inoculation (MPI, during which time the pathogen did not spread significantly beyond the inoculation site nor were there differences in lesion lengths between inoculated and non-inoculated plants. The pathogenic phase occurred between 1.5 and 2 MPI, when recovery beyond the inoculation site increased and lesion lengths of inoculated plants tripled. By 2 MPI, inoculated plants also had decreased starch content in xylem fibers and rays, and increased levels of gel-occluded xylem vessels, the latter of which HRCT revealed at a higher frequency than microscopy. RNA-Seq and screening of 21 grape expression datasets identified 20 candidate genes that were transcriptionally-activated by infection during the latent phase, and confirmed that the four best candidates (galactinol synthase, abscisic acid-induced wheat plasma membrane polypeptide-19 ortholog, embryonic cell protein 63, BURP domain-containing protein were not affected by a range of common foliar and wood pathogens or abiotic stresses

  6. Production of anti-fungal volatiles by non-pathogenic Fusarium oxysporum and its efficacy in suppression of verticillium wilt of cotton

    Science.gov (United States)

    Aims: The study aimed to identify volatile organic compounds (VOCs) produced by the non-pathogenic Fusarium oxysporum (Fo) strain CanR-46, and to determine the anti-fungal spectrum and the control efficacy of the Fo-VOCs. Methods: The Fo-VOCs were identified by GC-MS. The antifungal activity of the...

  7. Fungal Diversity in Field Mold-Damaged Soybean Fruits and Pathogenicity Identification Based on High-Throughput rDNA Sequencing

    Directory of Open Access Journals (Sweden)

    Jiang Liu

    2017-05-01

    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.

  8. Carbon source-induced reprogramming of the cell wall proteome and secretome modulates the adherence and drug resistance of the fungal pathogen Candida albicans.

    NARCIS (Netherlands)

    Ene, I.V.; Heilmann, C.J.; Sorgo, A.G.; Walker, L.A.; de Koster, C.G.; Munro, C.A.; Klis, F.M.; Brown, A.J.P.

    2012-01-01

    The major fungal pathogen Candida albicans can occupy diverse microenvironments in its human host. During colonization of the gastrointestinal or urogenital tracts, mucosal surfaces, bloodstream, and internal organs, C. albicans thrives in niches that differ with respect to available nutrients and l

  9. Floral transition in maize infected with Sporisorium reilianum disrupts compatibility with this biotrophic fungal pathogen.

    Science.gov (United States)

    Zhang, Shaopeng; Gardiner, Jack; Xiao, Yannong; Zhao, Jiuran; Wang, Fengge; Zheng, Yonglian

    2013-05-01

    Sporisorium reilianum f. sp. zeae is an important biotrophic pathogen that causes head smut disease in maize. Head smut is not obvious until the tassels and ears emerge. S. reilianum has a very long life cycle that spans almost the entire developmental program of maize after the pathogen successfully invades the root. The aim of this study was to understand at a molecular level how this pathogen interacts with the host during its long life cycle, and how this interaction differs between susceptible and resistant varieties of maize after hyphal invasion. We investigated transcriptional changes in the resistant maize line Mo17 at four developmental stages using a maize 70mer-oligonucleotide microarray. We found that there was a lengthy compatible relationship between the pathogen and host until the early eighth-leaf stage. The resistance in Mo17 relied on the assignment of auxin and regulation of flavonoids in the early floral primordium during the early floral transition stage. We propose a model describing the putative mechanism of head smut resistance in Mo17 during floral transition. In the model, the synergistic regulations among auxin, flavonoids, and hyphal growth play a key role in maintaining compatibility with S. reilianum in the resistant maize line.

  10. Quantitative trait loci for resistance to two fungal pathogens in Quercus robur

    Science.gov (United States)

    Cécile Robin; Amira Mougou-Hamdane; Jean-Marc Gion; Antoine Kremer; Marie-Laure. Desprez-Loustau

    2012-01-01

    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...

  11. Meiosis Drives Extraordinary Genome Plasticity in the Haploid Fungal Plant Pathogen Mycosphaerella Graminicola

    Science.gov (United States)

    Meiosis in the plant-pathogenic fungus Mycosphaerella graminicola results in eight ascospores due to a mitotic division following the two meiotic divisions. The transient diploid phase allows for recombination among homologous chromosomes. However, some chromosomes of M. graminicola lack homologs an...

  12. Response of soybean fungal and oomycete pathogens to apigenin and genistein

    Science.gov (United States)

    Plants recognize invading pathogens and respond biochemically to prevent invasion or inhibit the colonization of plant cells. Many plant defense compounds are flavonoids and some of these are known to have a broad spectrum of biological activity. In this study, we tested two flavonoids, apigenin and...

  13. Comparative genomics of the fungal pathogens Candida dubliniensis and Candida albicans.

    LENUS (Irish Health Repository)

    Jackson, Andrew P

    2009-12-01

    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.

  14. Root rot of peas in the Netherlands: fungal pathogens, inoculum potential and soil receptivity.

    NARCIS (Netherlands)

    Oyarzun, P.J.

    1994-01-01

    Fungi associated to pea (Pisum sativum L.) root rot were studied. Fusarium and Oomycetes were most common. Fusarium solani f. sp. pisi, Fsp, was widely distributed and the most frequent fungus in roots of diseased crops. The pathogens Thielaviopsis basicola , Tb, and Aphanomyces euteiches, Ae, wer

  15. Induction of programmed cell death in lily by the fungal pathogen Botrytis elliptica

    NARCIS (Netherlands)

    Baarlen, van P.; Staats, M.; Kan, van J.A.L.

    2004-01-01

    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 deat

  16. Polymorphic DNA sequences of the fungal honey bee pathogen Ascosphaera apis

    DEFF Research Database (Denmark)

    Jensen, Annette B; Welker, Dennis L; Kryger, Per

    2012-01-01

    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...

  17. Ovicidal activity of two fungal pathogens (Hyphomycetes) against Tetranychus cinnabarinus (Acarina:Tetranichidae)

    Institute of Scientific and Technical Information of China (English)

    SHI Weibin; FENG Mingguang

    2004-01-01

    The carmine spider mite, Tetranychus cinnabarinus, is an economically important pest that devastates varieties of crops worldwide and develops significant resistance to common chemical pesticides, most of which lack ovicidal activity. In the present study, two isolates of entomopathogenic fungi, Beuaveria bassiana SG8702 and Paecilomyces fumosoroseus Pfr153, were bioassayed against T. cinnabarinus eggs at 25℃ under a photophase of 12∶12 (L∶D). Infected eggs on Vicia faba var. minor leaves failed to hatch due to distortion and shrinkage and had fungal outgrowths when maintained under moist conditions. Sprays of B. bassiana conidia to T. cinnabarinus eggs (on leaves) at the concentrations of 58, 298 and 1306 conidia/mm2 (3 replicates per concentration and 35-65 fresh mite eggs per replicate) resulted in corrected egg mortalities of 20.4±4.2%, 36.0±7.6% and 64.6(12.5% (F=43.14, P <0.01), respectively; sprays of P. fumosoroseus at 129, 402 and 2328 conidia/mm2 caused egg mortalities of 16.1±11.1%, 44.2±13.3%, and 63.4±11.7% (F= 15.37, P=0.01), respectively. In contrast, natural egg mortalities in blank controls were 7.8% and 10.3% only. Based on probit analysis, the estimates of LC50 with 95% confidential limits were 548 (393-858) conidia/mm2 for B. bassiana and 914 (625-1550) for P. fumosoroseus, respectively. Apparently, both fungal species were capable of infecting T. cinnabarinus eggs, but the ovicidal activity of the B. bassiana isolate was greater than that of the P. fumosoroseus isolate. This represents the first report on the ovicidal activity of the two entomopathogenic Hyphomycetes against T. cinnabarinus.

  18. The structures of the honeydew oligosaccharides synthesized by Claviceps africana Análise estrutural dos oligossacarídeos presentes no exsudato da doença açucarada do sorgo, sintetizados por Claviceps africana

    Directory of Open Access Journals (Sweden)

    Amauri Bogo

    2006-03-01

    Full Text Available The structures of the principal oligosaccharides in the honeydew exudate of the sorghum ergot pathogen Claviceps africana, which has become epidemic in the Americas, have been characterized through linkage analysis using FAB-MS and GC-MS techniques, as 1,6-di-b-D-fructofuranosyl-D-mannitol and 1,5-di-b-D-fructofuranosyl-D-arabitol trisaccharides, 1-b-D-fructofuranosyl-D-mannitol and 5-b-D-fructofuranosyl-D-arabitol disaccharides and other minor disaccharides and trisaccharides. Their structural diversity is explained according to perceived biosynthetic interrelationships in pathways that appear to be unique amongst ergot fungi, particularly concerning intra-molecular reduction of fructose. The oligosaccharide, 1,6-di-b-D-fructofuranosyl-D-mannitol, which inhibits C. africana macrospore germination at a concentration in water of 1 g/mL or more, forms together with other slightly less bioactive oligosaccharides, the basis of a novel strategy to limit ergot disease losses in hybrid sorghum seed production.As estruturas dos principais oligossacarídeos presentes no exsudato da doença açucarada do sorgo, produzidos pelo patógeno Claviceps africana, foram caracterizadas através de espectroscopia de bombardeamento rápido de átomos-espectrometria de massa (FAB-MS e cromatografia gasosa-espectrometria de massa (GC-MS. Dois grupos de oligossacarídeos foram elucidados, sendo o principal formado pelos trissacarídeos 1,6-di-b-D-frutofuranosil-D-manitol e 1,5-di-b-D-frutofuranosil-D-arabitol e os dissacarídeos 1-b-D-frutofuranosil-D-manitol e 5-b-D-frutofuranosil-D-arabitol e outros grupos menos importantes de dissacarídeos e trissacarídeos. As diversidades estruturais foram elucidadas de acordo com a inter-relação biossintética de sua rota metabólica, a qual parece ser exclusiva entre os fungos produtores da doença "ergot", particularmente com relação a redução intramolecular da frutose. O oligossacarídeo 1,6-di

  19. High-resolution transcript profiling of the atypical biotrophic interaction between Theobroma cacao and the fungal pathogen Moniliophthora perniciosa.

    Science.gov (United States)

    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

    2014-11-01

    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.

  20. Germin-like protein 2 gene promoter from rice is responsive to fungal pathogens in transgenic potato plants.

    Science.gov (United States)

    Munir, Faiza; Hayashi, Satomi; Batley, Jacqueline; Naqvi, Syed Muhammad Saqlan; Mahmood, Tariq

    2016-01-01

    Controlled transgene expression via a promoter is particularly triggered in response to pathogen infiltration. This is significant for eliciting disease-resistant features in crops through genetic engineering. The germins and germin-like proteins (GLPs) are known to be associated with plant and developmental stages. The 1107-bp Oryza sativa root GLP2 (OsRGLP2) gene promoter fused to a β-glucuronidase (GUS) reporter gene was transformed into potato plants through an Agrobacterium-mediated transformation. The OsRGLP2 promoter was activated in response to Fusarium solani (Mart.) Sacc. and Alternaria solani Sorauer. Quantitative real-time PCR results revealed 4-5-fold increase in promoter activity every 24 h following infection. There was a 15-fold increase in OsRGLP2 promoter activity after 72 h of F. solani (Mart.) Sacc. treatment and a 12-fold increase observed with A. solani Sorauer. Our results confirmed that the OsRGLP2 promoter activity was enhanced under fungal stress. Furthermore, a hyperaccumulation of H2O2 in transgenic plants is a clear signal for the involvement of OsRGLP2 promoter region in the activation of specific genes in the potato genome involved in H2O2-mediated defense response. The OsRGLP2 promoter evidently harbors copies of GT-I and Dof transcription factors (AAAG) that act in response to elicitors generated in the wake of pathogen infection.

  1. The tetraspanin gene ClPLS1 is essential for appressorium-mediated penetration of the fungal pathogen Colletotrichum lindemuthianum.

    Science.gov (United States)

    Veneault-Fourrey, Claire; Parisot, Denise; Gourgues, Mathieu; Laugé, Richard; Lebrun, Marc-Henri; Langin, Thierry

    2005-04-01

    Conservation of the molecular mechanisms controlling appressorium-mediated penetration during evolution was assessed through a functional study of the ClPLS1 gene from Colletotrichum lindemuthianum orthologous to the MgPLS1 from Magnaporthe grisea, involved in penetration peg development. These two plant-pathogenic Pyrenomycetes differentiate appressoria to penetrate into plant tissues. We showed that ClPLS1 is a functional homologue of MgPLS1 in M. grisea. Loss of ClPLS1 function had no effect on vegetative growth, conidiation or on appressorium differentiation and maturation. However, Clpls1::hph mutants are non-pathogenic on either intact or wounded bean leaves, as a result of a defect in the formation and/or positioning of the penetration pore and consequently in the formation of the penetration peg. These observations suggest that the fungal tetraspanins control a conserved appressorial function that could be required for the correct localization of the site where the penetration peg emerges.

  2. Fungal pathogens of the genus Fusarium in winter wheat Triticum aestivum L. protected with fungicides in north-eastern Poland

    Directory of Open Access Journals (Sweden)

    Agnieszka Pszczółkowska

    2013-07-01

    Full Text Available Various diagnostic methods were used to evaluate the effect of fungicide protection on the prevalence of pathogenic fungi in wheat grain. Winter wheat cv. Nutka and Zyta was grown during a field experiment established in the Production and Experimental Station in Bałcyny in 2006–2007. The experimental factor was chemical crop protection: epoxiconazole, kresoxim-methyl and fenpropimorph applied at growth stages BBCH 33–35 as well as dimoxystrobin and epoxiconazole applied at BBCH 51–53. In this experiment, microscopic observations and conventional PCR assays were used as complementary methods. The quantification of Fusarium poae DNA by qPCR demonstrated the effectiveness of chemical protection against the analyzed fungal species. Lower monthly precipitation levels and higher daily temperatures intensified grain infections, in particular those caused by F. poae. A significant correlation was determined between the number of F. poae cultures isolated from winter wheat grain and the quantity of pathogenic DNA in grain identified by qPCR. Grain infections caused by F. poae lowered yield and thousand seed weight.

  3. Transformation of the Fungal Soybean Pathogen Cercospora kikuchii with the Selectable Marker bar

    OpenAIRE

    Upchurch, Robert G.; Meade, Maura J.; Hightower, Robin C.; Thomas, Robert S.; Callahan, Terrence M.

    1994-01-01

    An improved transformation protocol, utilizing selection for resistance to the herbicide bialaphos, has been developed for the plant pathogenic fungus Cercospora kikuchii. Stable, bialaphos-resistant transformants are recovered at frequencies eight times higher than those achieved with the previous system that was based on selection for benomyl resistance. In addition to C. kikuchii, this improved method can also be used to transform other species of Cercospora.

  4. Transformation of the Fungal Soybean Pathogen Cercospora kikuchii with the Selectable Marker bar.

    Science.gov (United States)

    Upchurch, R G; Meade, M J; Hightower, R C; Thomas, R S; Callahan, T M

    1994-12-01

    An improved transformation protocol, utilizing selection for resistance to the herbicide bialaphos, has been developed for the plant pathogenic fungus Cercospora kikuchii. Stable, bialaphos-resistant transformants are recovered at frequencies eight times higher than those achieved with the previous system that was based on selection for benomyl resistance. In addition to C. kikuchii, this improved method can also be used to transform other species of Cercospora.

  5. CLNR1, the AREA/NIT2-like global nitrogen regulator of the plant fungal pathogen Colletotrichum lindemuthianum is required for the infection cycle.

    Science.gov (United States)

    Pellier, Anne-Laure; Laugé, Richard; Veneault-Fourrey, Claire; Langin, Thierry

    2003-05-01

    Nitrogen starvation is generally assumed to be encountered by biotrophic and hemibiotrophic plant fungal pathogens at the beginning of their infection cycle. We tested whether nitrogen starvation constitutes a cue regulating genes that are required for pathogenicity of Colletotrichum lindemuthianum, a fungal pathogen of common bean. The clnr1 (C. lindemuthianumnitrogen regulator 1) gene, the areA/nit-2 orthologue of C. lindemuthianum, was isolated. The predicted CLNR1 protein exhibits high amino acid sequence similarities with the AREA and NIT2 global fungal nitrogen regulators. Targeted clnr1- mutants are unable to use a wide array of nitrogen sources, indicating that clnr1 is the C. lindemuthianum major nitrogen regulatory gene. The clnr1- mutants are non-pathogenic, although few anthracnose lesions seldom occur on whole plantlets. Surprisingly, cytological analysis reveals that the clnr1- mutants are not disturbed from the penetration stage until the end of the biotrophic phase, but that they are impaired during the setting up of the necrotrophic phase. Thus, through CLNR1, nitrogen starvation constitutes a cue for the regulation of genes that are compulsory for this stage of the C. lindemuthianum infection process. Additionally, clnr1- mutants complemented with the Aspergillus nidulans areA gene are fully pathogenic, indicating that areA is able to activate the C. lindemuthianum suited genes, normally under the control of clnr1.

  6. Opportunistic invasive fungal pathogen Macrophomina phaseolina prognosis from immunocompromised humans to potential mitogenic RBL with an exceptional and novel antitumor and cytotoxic effect.

    Science.gov (United States)

    Arora, P; Dilbaghi, N; Chaudhury, A

    2012-02-01

    With the ever-increasing risk for fungal infections, one can no longer ignore fungi. It is imperative that clinical manifestations "presume fungus" with their epidemiologic and pathogenic features when evaluating a potentially infected patient. In the high-risk patient groups, fungi with intrinsic resistance to antifungal agents already exist, with a tendency to emerge as opportunistic pathogens. One of the smart pathogens is Macrophomina phaseolina, with the potential to disarm plant, animal, and human immunity. The response prophylaxis may vary from antifungal therapy and surgical measures to biochemical (Rhizoctonia bataticola lectin [RBL] with antitumor and cytotoxic nature) and gene therapeutics.

  7. Fungal Control of Pathogenic Fungi Isolated From Some Wild Plants in Taif Governorate, Saudi Arabia

    Directory of Open Access Journals (Sweden)

    Abou-Zeid, A. M.

    2008-01-01

    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.

  8. Heterokaryon incompatibility is suppressed following conidial anastomosis tube fusion in a fungal plant pathogen.

    Science.gov (United States)

    Ishikawa, Francine H; Souza, Elaine A; Shoji, Jun-Ya; Connolly, Lanelle; Freitag, Michael; Read, Nick D; Roca, M Gabriela

    2012-01-01

    It has been hypothesized that horizontal gene/chromosome transfer and parasexual recombination following hyphal fusion between different strains may contribute to the emergence of wide genetic variability in plant pathogenic and other fungi. However, the significance of vegetative (heterokaryon) incompatibility responses, which commonly result in cell death, in preventing these processes is not known. In this study, we have assessed this issue following different types of hyphal fusion during colony initiation and in the mature colony. We used vegetatively compatible and incompatible strains of the common bean pathogen Colletotrichum lindemuthianum in which nuclei were labelled with either a green or red fluorescent protein in order to microscopically monitor the fates of nuclei and heterokaryotic cells following hyphal fusion. As opposed to fusion of hyphae in mature colonies that resulted in cell death within 3 h, fusions by conidial anastomosis tubes (CAT) between two incompatible strains during colony initiation did not induce the vegetative incompatibility response. Instead, fused conidia and germlings survived and formed heterokaryotic colonies that in turn produced uninucleate conidia that germinated to form colonies with phenotypic features different to those of either parental strain. Our results demonstrate that the vegetative incompatibility response is suppressed during colony initiation in C. lindemuthianum. Thus, CAT fusion may allow asexual fungi to increase their genetic diversity, and to acquire new pathogenic traits.

  9. Heterokaryon incompatibility is suppressed following conidial anastomosis tube fusion in a fungal plant pathogen.

    Directory of Open Access Journals (Sweden)

    Francine H Ishikawa

    Full Text Available It has been hypothesized that horizontal gene/chromosome transfer and parasexual recombination following hyphal fusion between different strains may contribute to the emergence of wide genetic variability in plant pathogenic and other fungi. However, the significance of vegetative (heterokaryon incompatibility responses, which commonly result in cell death, in preventing these processes is not known. In this study, we have assessed this issue following different types of hyphal fusion during colony initiation and in the mature colony. We used vegetatively compatible and incompatible strains of the common bean pathogen Colletotrichum lindemuthianum in which nuclei were labelled with either a green or red fluorescent protein in order to microscopically monitor the fates of nuclei and heterokaryotic cells following hyphal fusion. As opposed to fusion of hyphae in mature colonies that resulted in cell death within 3 h, fusions by conidial anastomosis tubes (CAT between two incompatible strains during colony initiation did not induce the vegetative incompatibility response. Instead, fused conidia and germlings survived and formed heterokaryotic colonies that in turn produced uninucleate conidia that germinated to form colonies with phenotypic features different to those of either parental strain. Our results demonstrate that the vegetative incompatibility response is suppressed during colony initiation in C. lindemuthianum. Thus, CAT fusion may allow asexual fungi to increase their genetic diversity, and to acquire new pathogenic traits.

  10. Foliar treatments with Gaultheria procumbens essential oil induce defence responses and resistance against a fungal pathogen in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Sophie eVergnes

    2014-09-01

    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.

  11. Fungal pathogens and antagonists in root-soil zone in organic and integrated systems of potato production

    Directory of Open Access Journals (Sweden)

    Lenc Leszek

    2016-04-01

    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.

  12. CD103+ Conventional Dendritic Cells Are Critical for TLR7/9-Dependent Host Defense against Histoplasma capsulatum, an Endemic Fungal Pathogen of Humans.

    Directory of Open Access Journals (Sweden)

    Nancy Van Prooyen

    2016-07-01

    Full Text Available Innate immune cells shape the host response to microbial pathogens. Here we elucidate critical differences in the molecular response of macrophages vs. dendritic cells (DCs to Histoplasma capsulatum, an intracellular fungal pathogen of humans. It has long been known that macrophages are permissive for Histoplasma growth and succumb to infection, whereas DCs restrict fungal growth and survive infection. We used murine macrophages and DCs to identify host pathways that influence fungal proliferation and host-cell viability. Transcriptional profiling experiments revealed that DCs produced a strong Type I interferon (IFN-I response to infection with Histoplasma yeasts. Toll-like receptors 7 and 9 (TLR7/9, which recognize nucleic acids, were required for IFN-I production and restriction of fungal growth in DCs, but mutation of TLR7/9 had no effect on the outcome of macrophage infection. Moreover, TLR7/9 were essential for the ability of infected DCs to elicit production of the critical cytokine IFNγ from primed CD4+ T cells in vitro, indicating the role of this pathway in T cell activation. In a mouse model of infection, TLR7/9 were required for optimal production of IFN-I and IFNγ, host survival, and restriction of cerebral fungal burden. These data demonstrate the critical role of this pathway in eliciting an appropriate adaptive immune response in the host. Finally, although other fungal pathogens have been shown to elicit IFN-I in mouse models, the specific host cell responsible for producing IFN-I has not been elucidated. We found that CD103+ conventional DCs were the major producer of IFN-I in the lungs of wild-type mice infected with Histoplasma. Mice deficient in this DC subtype displayed reduced IFN-I production in vivo. These data reveal a previously unknown role for CD103+ conventional DCs and uncover the pivotal function of these cells in modulating the host immune response to endemic fungi.

  13. Ancient dispersal of the human fungal pathogen Cryptococcus gattii from the Amazon rainforest.

    Directory of Open Access Journals (Sweden)

    Ferry Hagen

    Full Text Available 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.

  14. Ancient dispersal of the human fungal pathogen Cryptococcus gattii from the Amazon rainforest.

    Science.gov (United States)

    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

    2013-01-01

    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.

  15. Regulation of Sterol Biosynthesis in the Human Fungal Pathogen Aspergillus fumigatus: Opportunities for Therapeutic Development

    Science.gov (United States)

    Dhingra, Sourabh; Cramer, Robert A.

    2017-01-01

    Sterols are a major component of eukaryotic cell membranes. For human fungal infections caused by the filamentous fungus Aspergillus fumigatus, antifungal drugs that target sterol biosynthesis and/or function remain the standard of care. Yet, an understanding of A. fumigatus sterol biosynthesis regulatory mechanisms remains an under developed therapeutic target. The critical role of sterol biosynthesis regulation and its interactions with clinically relevant azole drugs is highlighted by the basic helix loop helix (bHLH) class of transcription factors known as Sterol Regulatory Element Binding Proteins (SREBPs). SREBPs regulate transcription of key ergosterol biosynthesis genes in fungi including A. fumigatus. In addition, other emerging regulatory pathways and target genes involved in sterol biosynthesis and drug interactions provide additional opportunities including the unfolded protein response, iron responsive transcriptional networks, and chaperone proteins such as Hsp90. Thus, targeting molecular pathways critical for sterol biosynthesis regulation presents an opportunity to improve therapeutic options for the collection of diseases termed aspergillosis. This mini-review summarizes our current understanding of sterol biosynthesis regulation with a focus on mechanisms of transcriptional regulation by the SREBP family of transcription factors. PMID:28203225

  16. Selectable genes for transformation of the fungal plant pathogen Glomerella cingulata f. sp. phaseoli (Colletotrichum lindemuthianum).

    Science.gov (United States)

    Rodriguez, R J; Yoder, O C

    1987-01-01

    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.

  17. Farnesol induces apoptosis and oxidative stress in the fungal pathogen Penicillium expansum.

    Science.gov (United States)

    Liu, Pu; Luo, Li; Guo, Junhong; Liu, Huimin; Wang, Baoquan; Deng, Boxun; Long, Chao-an; Cheng, Yunjiang

    2010-01-01

    This study was conducted to evaluate the effect of farnesol (FOH) on the growth of P. expansum. The viability of P. expansum cells was determined by counting the colony forming units (CFU) after each FOH treatment. Morphological changes of FOH-treated fungal cells were analyzed by staining with Hoechst 33258, TUNEL (terminal deoxynucleotidyl transferase fluorescein-12-dUTP nick end labeling), Annexin-V FITC and the oxidant-sensitive probe H2DCFDA (dichlorodihydro-fluorescein diacetate). FOH strongly inhibited the growth of hyphae. The hyphal cells showed the hallmarks of apoptosis including chromatin condensation, DNA fragmentation, phosphatidylserine (PS) externalization, caspases activation, intracellular reactive oxygen species (ROS) generation but without nucleosomal ladder production. The abnormal cellular ultrastructure observed by transmission electron microscope (TEM) indicated that disintegration of cellular ultrastructure (especially for mitochondria) was linked to FOH-induced cell death. Taken together we demonstrated that FOH inhibits the growth of P. expansum and promotes apoptosis via activation of metacaspases, production of ROS and disintegration of cellular ultrastructure.

  18. Inhibition of fungal plant pathogens by synergistic action of chito-oligosaccharides and commercially available fungicides.

    Directory of Open Access Journals (Sweden)

    Md Hafizur Rahman

    Full Text Available Chitosan is a linear heteropolymer consisting of β 1,4-linked N-acetyl-D-glucosamine (GlcNAc and D-glucosamine (GlcN. We have compared the antifungal activity of chitosan with DPn (average degree of polymerization 206 and FA (fraction of acetylation 0.15 and of enzymatically produced chito-oligosaccharides (CHOS of different DPn alone and in combination with commercially available synthetic fungicides, against Botrytis cinerea, the causative agent of gray mold in numerous fruit and vegetable crops. CHOS with DPn in the range of 15-40 had the greatest anti-fungal activity. The combination of CHOS and low dosages of synthetic fungicides showed synergistic effects on antifungal activity in both in vitro and in vivo assays. Our study shows that CHOS enhance the activity of commercially available fungicides. Thus, addition of CHOS, available as a nontoxic byproduct of the shellfish industry, may reduce the amounts of fungicides that are needed to control plant diseases.

  19. Intracellular growth is dependent on tyrosine catabolism in the dimorphic fungal pathogen Penicillium marneffei.

    Science.gov (United States)

    Boyce, Kylie J; McLauchlan, Alisha; Schreider, Lena; Andrianopoulos, Alex

    2015-03-01

    During infection, pathogens must utilise the available nutrient sources in order to grow while simultaneously evading or tolerating the host's defence systems. Amino acids are an important nutritional source for pathogenic fungi and can be assimilated from host proteins to provide both carbon and nitrogen. The hpdA gene of the dimorphic fungus Penicillium marneffei, which encodes an enzyme which catalyses the second step of tyrosine catabolism, was identified as up-regulated in pathogenic yeast cells. As well as enabling the fungus to acquire carbon and nitrogen, tyrosine is also a precursor in the formation of two types of protective melanin; DOPA melanin and pyomelanin. Chemical inhibition of HpdA in P. marneffei inhibits ex vivo yeast cell production suggesting that tyrosine is a key nutrient source during infectious growth. The genes required for tyrosine catabolism, including hpdA, are located in a gene cluster and the expression of these genes is induced in the presence of tyrosine. A gene (hmgR) encoding a Zn(II)2-Cys6 binuclear cluster transcription factor is present within the cluster and is required for tyrosine induced expression and repression in the presence of a preferred nitrogen source. AreA, the GATA-type transcription factor which regulates the global response to limiting nitrogen conditions negatively regulates expression of cluster genes in the absence of tyrosine and is required for nitrogen metabolite repression. Deletion of the tyrosine catabolic genes in the cluster affects growth on tyrosine as either a nitrogen or carbon source and affects pyomelanin, but not DOPA melanin, production. In contrast to other genes of the tyrosine catabolic cluster, deletion of hpdA results in no growth within macrophages. This suggests that the ability to catabolise tyrosine is not required for macrophage infection and that HpdA has an additional novel role to that of tyrosine catabolism and pyomelanin production during growth in host cells.

  20. GATA transcription factor required for immunity to bacterial and fungal pathogens.

    Directory of Open Access Journals (Sweden)

    Samantha Kerry

    Full Text Available 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-kappaB. 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.

  1. Isolation and Characterization of Actinomycete Antagonists of a Fungal Root Pathogen

    Science.gov (United States)

    Crawford, Don L.; Lynch, James M.; Whipps, John M.; Ousley, Margaret A.

    1993-01-01

    By use of selective media, 267 actinomycete strains were isolated from four rhizosphere-associated and four non-rhizosphere-associated British soils. Organic media with low nutrient concentrations were found to be best for isolating diverse actinomycetes while avoiding contamination and overgrowth of isolation media by eubacteria and fungi. While all isolates grew well at pHs 6.5 to 8.0, a few were unable to grow at pH 6.0 and a significant number failed to grow at pH 5.5. Eighty-two selected isolates were screened for in vitro antagonism towards Pythium ultimum by use of a Difco cornmeal agar assay procedure. Five isolates were very strong antagonists of the fungus, four were strong antagonists, and ten others were weakly antagonistic. The remaining isolates showed no antagonism by this assay. Additional studies showed that several of the P. ultimum antagonists also strongly inhibited growth of other root-pathogenic fungi. Twelve isolates showing antifungal activity in the in vitro assay were also tested for their effects on the germination and short-term growth of lettuce plants in glasshouse pot studies in the absence of pathogens. None of the actinomycetes prevented seed germination, although half of the isolates retarded seed germination and outgrowth of the plants by 1 to 3 days. During 18-day growth experiments, biomass yields of some actinomycete-inoculated plants were reduced in comparison with untreated control plants, although all plants appeared healthy and well rooted. None of the actinomycetes significantly enhanced plant growth over these short-term experiments. For some, but not all, actinomycetes, some correlations between delayed seed germination and reduced 18-day plant biomass yields were seen. For others, plant biomass yields were not reduced despite an actinomycete-associated delay in seed germination and plant outgrowth. Preliminary glasshouse experiments indicated that some of the actinomycetes protect germinating lettuce seeds against

  2. Molecular Characterization and Diagnosis of QoI Resistance in Cucumber and Eggplant Fungal Pathogens.

    Science.gov (United States)

    Ishii, H; Yano, K; Date, H; Furuta, A; Sagehashi, Y; Yamaguchi, T; Sugiyama, T; Nishimura, K; Hasama, W

    2007-11-01

    ABSTRACT The molecular mechanism of QoI fungicide resistance was studied using isolates of cucumber Corynespora leaf spot fungus (Corynespora cassiicola) and the eggplant leaf mold (Mycovellosiella nattrassii). In both pathogens, a mutation at position 143 from glycine to alanine (G143A) was detected in the cytochrome b gene that encodes for the fungicide-targeted protein. Moreover, the nucleotide sequence at amino acid position 143 was converted from GGT or GGA in sensitive (wild-type) to GCT or GCA in resistant (mutant-type) isolates. The methods of polymerase chain reaction restriction fragment length polymorphism commonly used for QoI resistance monitoring were employed successfully, leading to the amplified gene fragment from resistant isolates being cut with the restriction enzyme ItaI. However, heteroplasmy (the coexistence of wild-type and mutated alleles) was found when the resistant isolates of C. cassiicola, M. nattrassii, and Colletotrichum gloeosporioides (strawberry anthracnose fungus) were subcultured in the presence or absence of QoI fungicides. QoI resistance of cucumber powdery and downy mildew isolates persisted for a few years following the removal of the selection pressure imposed by the fungicide under both laboratory and commercial greenhouse conditions. The proportion of mutated sequences in cytochrome b gene decreased over time in the pathogen population. The protective efficacy of the full dose of azoxystrobin decreased when the populations of powdery and downy mildews contained resistant isolates at 10%. Using FMBIO, a fluorescence bio-imaging analyzer, the mutant allele from the QoI-resistant isolates could be detected at the level of 1%, whereas the detection sensitivity of ethidium-bromide-stained gels was approximately 10 times lower.

  3. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for rapid identification of fungal rhinosinusitis pathogens.

    Science.gov (United States)

    Huang, Yanfei; Wang, Jinglin; Zhang, Mingxin; Zhu, Min; Wang, Mei; Sun, Yufeng; Gu, Haitong; Cao, Jingjing; Li, Xue; Zhang, Shaoya; Lu, Xinxin

    2017-03-01

    Filamentous fungi are among the most important pathogens, causing fungal rhinosinusitis (FRS). Current laboratory diagnosis of FRS pathogens mainly relies on phenotypic identification by culture and microscopic examination, which is time consuming and expertise dependent. Although matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) MS has been employed to identify various fungi, its efficacy in the identification of FRS fungi is less clear. A total of 153 FRS isolates obtained from patients were analysed at the Clinical Laboratory at the Beijing Tongren Hospital affiliated to the Capital Medical University, between January 2014 and December 2015. They were identified by traditional phenotypic methods and Bruker MALDI-TOF MS (Bruker, Biotyper version 3.1), respectively. Discrepancies between the two methods were further validated by sequencing. Among the 153 isolates, 151 had correct species identification using MALDI-TOF MS (Bruker, Biot 3.1, score ≥2.0 or 2.3). MALDI-TOF MS enabled identification of some very closely related species that were indistinguishable by conventional phenotypic methods, including 1/10 Aspergillus versicolor, 3/20 Aspergillus flavus, 2/30 Aspergillus fumigatus and 1/20 Aspergillus terreus, which were misidentified by conventional phenotypic methods as Aspergillus nidulans, Aspergillus oryzae, Aspergillus japonicus and Aspergillus nidulans, respectively. In addition, 2/2 Rhizopus oryzae and 1/1 Rhizopus stolonifer that were identified only to the genus level by the phenotypic method were correctly identified by MALDI-TOF MS. MALDI-TOF MS is a rapid and accurate technique, and could replace the conventional phenotypic method for routine identification of FRS fungi in clinical microbiology laboratories.

  4. The Arabidopsis Mediator Complex Subunit16 Is a Key Component of Basal Resistance against the Necrotrophic Fungal Pathogen Sclerotinia sclerotiorum.

    Science.gov (United States)

    Wang, Chenggang; Yao, Jin; Du, Xuezhu; Zhang, Yanping; Sun, Yijun; Rollins, Jeffrey A; Mou, Zhonglin

    2015-09-01

    Although Sclerotinia sclerotiorum is a devastating necrotrophic fungal plant pathogen in agriculture, the virulence mechanisms utilized by S. sclerotiorum and the host defense mechanisms against this pathogen have not been fully understood. Here, we report that the Arabidopsis (Arabidopsis thaliana) Mediator complex subunit MED16 is a key component of basal resistance against S. sclerotiorum. Mutants of MED16 are markedly more susceptible to S. sclerotiorum than mutants of 13 other Mediator subunits, and med16 has a much stronger effect on S. sclerotiorum-induced transcriptome changes compared with med8, a mutation not altering susceptibility to S. sclerotiorum. Interestingly, med16 is also more susceptible to S. sclerotiorum than coronatine-insensitive1-1 (coi1-1), which is the most susceptible mutant reported so far. Although the jasmonic acid (JA)/ethylene (ET) defense pathway marker gene PLANT DEFENSIN1.2 (PDF1.2) cannot be induced in either med16 or coi1-1, basal transcript levels of PDF1.2 in med16 are significantly lower than in coi1-1. Furthermore, ET-induced suppression of JA-activated wound responses is compromised in med16, suggesting a role for MED16 in JA-ET cross talk. Additionally, MED16 is required for the recruitment of RNA polymerase II to PDF1.2 and OCTADECANOID-RESPONSIVE ARABIDOPSIS ETHYLENE/ETHYLENE-RESPONSIVE FACTOR59 (ORA59), two target genes of both JA/ET-mediated and the transcription factor WRKY33-activated defense pathways. Finally, MED16 is physically associated with WRKY33 in yeast and in planta, and WRKY33-activated transcription of PDF1.2 and ORA59 as well as resistance to S. sclerotiorum depends on MED16. Taken together, these results indicate that MED16 regulates resistance to S. sclerotiorum by governing both JA/ET-mediated and WRKY33-activated defense signaling in Arabidopsis.

  5. Genetic differentiation and recombination among geographic populations of the fungal pathogen Colletotrichum truncatum from chili peppers in China.

    Science.gov (United States)

    Diao, Yongzhao; Zhang, Can; Xu, Jianping; Lin, Dong; Liu, Li; Mtung'e, Olivo G; Liu, Xili

    2015-01-01

    Colletotrichum truncatum is an extremely important fungal pathogen. It can cause diseases both in humans and in over 460 plant species. However, little is known about its genetic diversity within and among populations. One of the major plant hosts of C. truncatum is pepper, and China is one of the main pepper-producing countries in the world. Here, we propose the hypotheses that geography has a major influence on the relationships among populations of C. truncatum in China and that infections in different populations need to be managed differently. To test these hypotheses, we obtained and analyzed 266 C. truncatum isolates from 13 regions representing the main pepper-growing areas throughout China. The analysis based on nine microsatellite markers identified high intrapopulation genetic diversity, evidence of sexual recombination, and geographic differentiation. The genetic differentiation was positively correlated with geographic distance, with the southern and northern China populations grouped in two distinct clusters. Interestingly, isolates collected from the pepper-breeding center harbored the most private alleles. The results suggest that the geographic populations of C. truncatum on peppers in China are genetically differentiated and should be managed accordingly. Our study also provides a solid foundation from which to further explore the global genetic epidemiology of C. truncatum in both plants and humans.

  6. Larval exposure to predator cues alters immune function and response to a fungal pathogen in post-metamorphic wood frogs.

    Science.gov (United States)

    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

    2013-09-01

    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.

  7. Biogenic ZnO nanoparticles synthesized using L. aculeata leaf extract and their antifungal activity against plant fungal pathogens

    Indian Academy of Sciences (India)

    S Narendhran; Rajeshwari Sivaraj

    2016-02-01

    In this study, Zinc oxide (ZnO) nanoparticles were synthesized using aqueous extract of Lantana aculeata Linn. leaf and assessed their effects on antifungal activity against the plant fungal pathogens. Synthesized nanoparticles were confirmed by ultraviolet–visible spectroscopy, Fourier transform infrared spectrometer, energy-dispersive X-ray spectrometer, X-ray diffractometer, Field-emission scanning electron microscopy, high-resolution transmission electron microscopy. The antifungal activity of ZnO nanoparticles were determined using the well diffusion method. All the characterization analyses revealed that nanoparticles were highly stable and crystalline in nature. L. aculeata-mediated ZnO nanoparticles were spherical in shape with an average particle size of 12 ± 3 nm. Antifungal studies concluded that the maximum zone of inhibition was observed in Aspergillus flavus (21 ± 1.0 mm) and Fusarium oxysporum (19 ± 1.0 mm) at 100 g ml-1 concentration. These results clearly indicated the benefits of using ZnO nanoparticles synthesized using biological methods and shown to have antifungal activities and also that it can be effectively used as antifungal agent in environmental aspect of agricultural development.

  8. Bioactivity of natural O-prenylated phenylpropenes from Illicium anisatum leaves and their derivatives against spider mites and fungal pathogens.

    Science.gov (United States)

    Koeduka, T; Sugimoto, K; Watanabe, B; Someya, N; Kawanishi, D; Gotoh, T; Ozawa, R; Takabayashi, J; Matsui, K; Hiratake, J

    2014-03-01

    A variety of volatile phenylpropenes, C6-C3 compounds are widely distributed in the plant kingdom, whereas prenylated phenylpropenes are limited to a few plant species. In this study, we analysed the volatile profiles from Illicium anisatum leaves and identified two O-prenylated phenylpropenes, 4-allyl-2-methoxy-1-[(3-methylbut-2-en-1-yl)oxy]benzene [O-dimethylallyleugenol (9)] and 5-allyl-1,3-dimethoxy-2-(3-methylbut-2-en-1-yl)oxy]benzene [O-dimethylallyl-6-methoxyeugenol (11)] as major constituents. The structure-activity relationship of a series of eugenol derivatives showed that specific phenylpropenes, including eugenol (1), isoeugenol (2) and 6-methoxyeugenol (6), with a phenolic hydroxy group had antifungal activity for a fungal pathogen, whereas guaiacol, a simple phenolic compound, and allylbenzene had no such activity. The eugenol derivatives that exhibited antifungal activity, in turn, had no significant toxicant property for mite oviposition. Interestingly, O-dimethylallyleugenol (9) in which the phenolic oxygen was masked with a dimethylallyl group exhibited a specific, potent oviposition deterrent activity for mites. The sharp contrast in structural requirements of phenylpropenes suggested distinct mechanisms underlying the two biological activities and the importance of a phenolic hydroxy group and its dimethylallylation for the structure-based design of new functional properties of phenylpropenes.

  9. Functional properties of a cysteine proteinase from pineapple fruit with improved resistance to fungal pathogens in Arabidopsis thaliana.

    Science.gov (United States)

    Wang, Wei; Zhang, Lu; Guo, Ning; Zhang, Xiumei; Zhang, Chen; Sun, Guangming; Xie, Jianghui

    2014-01-01

    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.

  10. Retransformation of marker-free potato for enhanced resistance against fungal pathogens by pyramiding chitinase and wasabi defensin genes.

    Science.gov (United States)

    Khan, Raham Sher; Darwish, Nader Ahmed; Khattak, Bushra; Ntui, Valentine Otang; Kong, Kynet; Shimomae, Kazuki; Nakamura, Ikuo; Mii, Masahiro

    2014-09-01

    Multi-auto-transformation vector system has been one of the strategies to produce marker-free transgenic plants without using selective chemicals and plant growth regulators and thus facilitating transgene stacking. In the study reported here, retransformation was carried out in marker-free transgenic potato CV. May Queen containing ChiC gene (isolated from Streptomyces griseus strain HUT 6037) with wasabi defensin (WD) gene (isolated from Wasabia japonica) to pyramid the two disease resistant genes. Molecular analyses of the developed shoots confirmed the existence of both the genes of interest (ChiC and WD) in transgenic plants. Co-expression of the genes was confirmed by RT-PCR, northern blot, and western blot analyses. Disease resistance assay of in vitro plants showed that the transgenic lines co-expressing both the ChiC and WD genes had higher resistance against the fungal pathogens, Fusarium oxysporum (Fusarium wilt) and Alternaria solani (early blight) compared to the non-transformed control and the transgenic lines expressing either of the ChiC or WD genes. The disease resistance potential of the transgenic plants could be increased by transgene stacking or multiple transformations.

  11. Functional Properties of a Cysteine Proteinase from Pineapple Fruit with Improved Resistance to Fungal Pathogens in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Wei Wang

    2014-02-01

    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.

  12. Nutritional study on Embellisia astragali, a fungal pathogen of milk vetch (Astragalus adsurgens).

    Science.gov (United States)

    Li, Yan Zhong; Nan, Zhi Biao

    2009-03-01

    Embellisia astragali is a strong, virulent pathogen that develops within milk vetch (Astragalus adsurgens). In order to determine nutrient requirements, the fungus was cultured on 9 carbon sources, 9 nitrogen sources, and 13 growth media in the dark at 25 degrees C. Growth rates and sporulation capacity were measured after 4 and 12 weeks. All carbon sources supported growth, but only soluble starch, inulin, and dextrose supported sporulation. In general, better growth was obtained on disaccharides and polysaccharides than on monosaccharides. Compared with no growth on NH(4) (+)-N and urea, the fungus grew little on all NO(3) (-)-N, amino-N, and other organic-N such as peptone. There was no sporulation or very sparse conidia on almost all nitrogen sources with supplied dextrose or soluble starch as sole carbon source. The better growth and sporulation on most of the semidefined media than on defined media indicates that some components in plant or animal material may be vital to the fungus. Sporulation was positively correlated with growth rate in N source experiment at 12 weeks and in growth media experiment at 4 and 12 weeks. The fungus favors grow within agar with growth rate less than 1.18 mm day(-1).

  13. A metabolic profiling strategy for the dissection of plant defense against fungal pathogens.

    Directory of Open Access Journals (Sweden)

    Konstantinos A Aliferis

    Full Text Available Here we present a metabolic profiling strategy employing direct infusion Orbitrap mass spectrometry (MS and gas chromatography-mass spectrometry (GC/MS for the monitoring of soybean's (Glycine max L. global metabolism regulation in response to Rhizoctonia solani infection in a time-course. Key elements in the approach are the construction of a comprehensive metabolite library for soybean, which accelerates the steps of metabolite identification and biological interpretation of results, and bioinformatics tools for the visualization and analysis of its metabolome. The study of metabolic networks revealed that infection results in the mobilization of carbohydrates, disturbance of the amino acid pool, and activation of isoflavonoid, α-linolenate, and phenylpropanoid biosynthetic pathways of the plant. Components of these pathways include phytoalexins, coumarins, flavonoids, signaling molecules, and hormones, many of which exhibit antioxidant properties and bioactivity helping the plant to counterattack the pathogen's invasion. Unraveling the biochemical mechanism operating during soybean-Rhizoctonia interaction, in addition to its significance towards the understanding of the plant's metabolism regulation under biotic stress, provides valuable insights with potential for applications in biotechnology, crop breeding, and agrochemical and food industries.

  14. Ergothioneine Biosynthesis and Functionality in the Opportunistic Fungal Pathogen, Aspergillus fumigatus

    Science.gov (United States)

    Sheridan, Kevin J.; Lechner, Beatrix Elisabeth; Keeffe, Grainne O’; Keller, Markus A.; Werner, Ernst R.; Lindner, Herbert; Jones, Gary W.; Haas, Hubertus; Doyle, Sean

    2016-01-01

    Ergothioneine (EGT; 2-mercaptohistidine trimethylbetaine) is a trimethylated and sulphurised histidine derivative which exhibits antioxidant properties. Here we report that deletion of Aspergillus fumigatus egtA (AFUA_2G15650), which encodes a trimodular enzyme, abrogated EGT biosynthesis in this opportunistic pathogen. EGT biosynthetic deficiency in A. fumigatus significantly reduced resistance to elevated H2O2 and menadione, respectively, impaired gliotoxin production and resulted in attenuated conidiation. Quantitative proteomic analysis revealed substantial proteomic remodelling in ΔegtA compared to wild-type under both basal and ROS conditions, whereby the abundance of 290 proteins was altered. Specifically, the reciprocal differential abundance of cystathionine γ-synthase and β-lyase, respectively, influenced cystathionine availability to effect EGT biosynthesis. A combined deficiency in EGT biosynthesis and the oxidative stress response regulator Yap1, which led to extreme oxidative stress susceptibility, decreased resistance to heavy metals and production of the extracellular siderophore triacetylfusarinine C and increased accumulation of the intracellular siderophore ferricrocin. EGT dissipated H2O2 in vitro, and elevated intracellular GSH levels accompanied abrogation of EGT biosynthesis. EGT deficiency only decreased resistance to high H2O2 levels which suggests functionality as an auxiliary antioxidant, required for growth at elevated oxidative stress conditions. Combined, these data reveal new interactions between cellular redox homeostasis, secondary metabolism and metal ion homeostasis. PMID:27748436

  15. Novel insights into mannitol metabolism in the fungal plant pathogen Botrytis cinerea.

    Science.gov (United States)

    Dulermo, Thierry; Rascle, Christine; Billon-Grand, Geneviève; Gout, Elisabeth; Bligny, Richard; Cotton, Pascale

    2010-03-29

    In order to redefine the mannitol pathway in the necrotrophic plant pathogen Botrytis cinerea, we used a targeted deletion strategy of genes encoding two proteins of mannitol metabolism, BcMTDH (B. cinerea mannitol dehydrogenase) and BcMPD (B. cinerea mannitol-1-phosphate dehydrogenase). Mobilization of mannitol and quantification of Bcmpd and Bcmtdh gene transcripts during development and osmotic stress confirmed a role for mannitol as a temporary and disposable carbon storage compound. In order to study metabolic fluxes, we followed conversion of labelled hexoses in wild-type and DeltaBcmpd and DeltaBcmtdh mutant strains by in vivo NMR spectroscopy. Our results revealed that glucose and fructose were metabolized via the BcMPD and BcMTDH pathways respectively. The existence of a novel mannitol phosphorylation pathway was also suggested by the NMR investigations. This last finding definitively challenged the existence of the originally postulated mannitol cycle in favour of two simultaneously expressed pathways. Finally, physiological and biochemical studies conducted on double deletion mutants (DeltaBcmpdDeltaBcmtdh) showed that mannitol was still produced despite a complete alteration of both mannitol biosynthesis pathways. This strongly suggests that one or several additional undescribed pathways could participate in mannitol metabolism in B. cinerea.

  16. A Metabolic Profiling Strategy for the Dissection of Plant Defense against Fungal Pathogens

    Science.gov (United States)

    Aliferis, Konstantinos A.; Faubert, Denis; Jabaji, Suha

    2014-01-01

    Here we present a metabolic profiling strategy employing direct infusion Orbitrap mass spectrometry (MS) and gas chromatography-mass spectrometry (GC/MS) for the monitoring of soybean's (Glycine max L.) global metabolism regulation in response to Rhizoctonia solani infection in a time-course. Key elements in the approach are the construction of a comprehensive metabolite library for soybean, which accelerates the steps of metabolite identification and biological interpretation of results, and bioinformatics tools for the visualization and analysis of its metabolome. The study of metabolic networks revealed that infection results in the mobilization of carbohydrates, disturbance of the amino acid pool, and activation of isoflavonoid, α-linolenate, and phenylpropanoid biosynthetic pathways of the plant. Components of these pathways include phytoalexins, coumarins, flavonoids, signaling molecules, and hormones, many of which exhibit antioxidant properties and bioactivity helping the plant to counterattack the pathogen's invasion. Unraveling the biochemical mechanism operating during soybean-Rhizoctonia interaction, in addition to its significance towards the understanding of the plant's metabolism regulation under biotic stress, provides valuable insights with potential for applications in biotechnology, crop breeding, and agrochemical and food industries. PMID:25369450

  17. Lasiolactols A and B Produced by the Grapevine Fungal Pathogen Lasiodiplodia mediterranea.

    Science.gov (United States)

    Andolfi, Anna; Basso, Sara; Giambra, Selene; Conigliaro, Gaetano; Lo Piccolo, Sandra; Alves, Artur; Burruano, Santella

    2016-04-01

    A strain of Lasiodiplodia mediterranea, a fungus associated with grapevine decline in Sicily, produced several metabolites in liquid medium. Two new dimeric γ-lactols, lasiolactols A and B (1 and 2), were characterized as (2S*,3S*,4R*,5R*,2'S*,3'S*,4'R*,5'R*)- and (2R*,3S*,4R*,5R*,2'R*,3'S*,4'R*,5'R*)-(5-(4-hydroxymethyl-3,5-dimethyl-tetrahydro-furan-2-yloxy)-2,4-dimethyl-tetrahydro-furan-3-yl]-methanols by IR, 1D- and 2D-NMR, and HR-ESI-MS. Other four metabolites were identified as botryosphaeriodiplodin, (5R)-5-hydroxylasiodiplodin, (-)-(1R,2R)-jasmonic acid, and (-)-(3S,4R,5R)-4-hydroxymethyl-3,5-dimethyldihydro-2-furanone (3 - 6, resp.). The absolute configuration (R) at hydroxylated secondary C-atom C(7) was also established for compound 3. The compounds 1 - 3, 5, and 6, tested for their phytotoxic activities to grapevine cv. Inzolia leaves at different concentrations (0.125, 0.25, 0.5, and 1 mg/ml) were phytotoxic and compound 5 showed the highest toxicity. All metabolites did not show in vitro antifungal activity against four plant pathogens.

  18. Claviceps cyperi, a new cause of severe ergotism in dairy cattle consuming maize silage and teff hay contaminated with ergotised Cyperus esculentus (nut sedge on the Highveld of South Africa

    Directory of Open Access Journals (Sweden)

    T.W. Naude

    2005-09-01

    late seasonal rain had resulted in mature, heavily ergotised nut sedge being cut with the silage. Claviceps cyperi sclerotia, collected on the affected fields in the following autumn contained 3 600-4 000 ppm ergocryptine. That the dominant alkaloid produced by this particular fungus was indeed ergocryptine, was confirmed by negative ion chemical ionization MS/MS. In one further outbreak in another Holstein herd, teff hay contaminated with ergotised nut sedge and containing 1 200 ppb alkaloids, was incriminated as the cause of the condition. This is the first report of bovine ergotism not associated with the Poaceae infected with Claviceps purpureum or endophytes but with the family Cyperaceae and this particular fungal phytopathogen.

  19. Localization of ergot alkaloids in sclerotia of Claviceps purpurea by matrix-assisted laser desorption/ionization mass spectrometry imaging.

    Science.gov (United States)

    Dopstadt, Julian; Vens-Cappell, Simeon; Neubauer, Lisa; Tudzynski, Paul; Cramer, Benedikt; Dreisewerd, Klaus; Humpf, Hans-Ulrich

    2017-02-01

    The fungus Claviceps purpurea produces highly toxic ergot alkaloids and accumulates these in the hardened bodies of fungal mycelium. These so-called sclerotia, or ergot bodies, replace the crop seed of infected plants, which can include numerous important food- and feedstuff such as rye and wheat. While several studies have explored details of the infection process and development of ergot bodies, little information is available on the spatial distribution of the mycotoxins in the sclerotia. Here we used matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) at a lateral resolution of 35 μm to visualize the distribution of two representative alkaloids, ergocristine and ergometrine, produced by Ecc93 and Gal 310 variants of C. purpurea, respectively, after infection of rye. To improve cryosectioning of this fragile biological material tissue with complex texture, we developed a practical embedding protocol based on cellulose polymers. The MALDI-MS images recorded from the so produced intact tissues sections revealed that ergometrine exhibited a relatively homogeneous distribution throughout the ergot body, whereas ergocristine was found to be enriched in the proximal region. This finding can be correlated to the morphological development of sclerotia as ergot alkaloids are only produced in the sphacelial stage. The ability to localize toxins and other secondary metabolites in intact sections of crop-infecting fungi with high lateral resolution renders MALDI-MSI a powerful tool for investigating biosynthetic pathways and for obtaining a deeper understanding of the parasite-host interaction. Graphical abstract Workflow for identification and spatial localization of ergot alkaloids in infected rye grains.

  20. Genome‐wide gene expression dynamics of the fungal pathogen Dothistroma septosporum throughout its infection cycle of the gymnosperm host Pinus radiata

    Science.gov (United States)

    Guo, Yanan; Sim, Andre D.; Kabir, M. Shahjahan; Chettri, Pranav; Ozturk, Ibrahim K.; Hunziker, Lukas; Ganley, Rebecca J.; Cox, Murray P.

    2015-01-01

    Summary We present genome‐wide gene expression patterns as a time series through the infection cycle of the fungal pine needle blight pathogen, Dothistroma septosporum, as it invades its gymnosperm host, Pinus radiata. We determined the molecular changes at three stages of the disease cycle: epiphytic/biotrophic (early), initial necrosis (mid) and mature sporulating lesion (late). Over 1.7 billion combined plant and fungal reads were sequenced to obtain 3.2 million fungal‐specific reads, which comprised as little as 0.1% of the sample reads early in infection. This enriched dataset shows that the initial biotrophic stage is characterized by the up‐regulation of genes encoding fungal cell wall‐modifying enzymes and signalling proteins. Later necrotrophic stages show the up‐regulation of genes for secondary metabolism, putative effectors, oxidoreductases, transporters and starch degradation. This in‐depth through‐time transcriptomic study provides our first snapshot of the gene expression dynamics that characterize infection by this fungal pathogen in its gymnosperm host. PMID:25919703

  1. Proteomic analysis of the secretions of Pseudallescheria boydii, a human fungal pathogen with unknown genome.

    Science.gov (United States)

    da Silva, Bianca Alcântara; Sodré, Cátia Lacerda; Souza-Gonçalves, Ana Luiza; Aor, Ana Carolina; Kneipp, Lucimar Ferreira; Fonseca, Beatriz Bastos; Rozental, Sonia; Romanos, Maria Teresa Villela; Sola-Penna, Mauro; Perales, Jonas; Kalume, Dário Eluan; dos Santos, André Luis Souza

    2012-01-01

    Pseudallescheria boydii is a filamentous fungus that causes a wide array of infections that can affect practically all the organs of the human body. The treatment of pseudallescheriosis is difficult since P. boydii exhibits intrinsic resistance to the majority of antifungal drugs used in the clinic and the virulence attributes expressed by this fungus are unknown. The study of the secretion of molecules is an important approach for understanding the pathogenicity of fungi. With this task in mind, we have shown that mycelial cells of P. boydii were able to actively secrete proteins into the extracellular environment; some of them were recognized by antibodies present in the serum of a patient with pseudallescheriosis. Additionally, molecules secreted by P. boydii induced in vitro irreversible damage in pulmonary epithelial cells. Subsequently, two-dimensional gel electrophoresis combined with mass spectrometry was carried out in order to start the construction of a map of secreted proteins from P. boydii mycelial cells. The two-dimensional map showed that most of the proteins (around 100 spots) were focused at pH ranging from 4 to 7 with molecular masses ranging from 14 to >117 kDa. Fifty spots were randomly selected, of which 30 (60%) were consistently identified, while 20 (40%) spots generated peptides that showed no resemblance to any known protein from other fungi and/or MS with low quality. Notably, we identified proteins involved in metabolic pathways (energy/carbohydrate, nucleotide, and fatty acid), cell wall remodeling, RNA processing, signaling, protein degradation/nutrition, translation machinery, drug elimination and/or detoxification, protection against environmental stress, cytoskeleton/movement proteins, and immunogenic molecules. Since the genome of this fungus is not sequenced, we performed enzymatic and immunodetection assays in order to corroborate the presence of some released proteins. The identification of proteins actively secreted by P

  2. MYT3, a Myb-like transcription factor, affects fungal development and pathogenicity of Fusarium graminearum.

    Directory of Open Access Journals (Sweden)

    Yongsoo Kim

    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.

  3. Evaluation of antioxidant and antifungal properties of the traditional plants against foodborne fungal pathogens.

    Science.gov (United States)

    Sharifzadeh, A; Javan, A Jebeli; Shokri, H; Abbaszadeh, S; Keykhosravy, K

    2016-03-01

    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.

  4. Mycobiome of the bat white nose syndrome affected caves and mines reveals diversity of fungi and local adaptation by the fungal pathogen Pseudogymnoascus (Geomyces destructans.

    Directory of Open Access Journals (Sweden)

    Tao Zhang

    Full Text Available 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.

  5. Crystal structures of the fungal pathogen Aspergillus fumigatus protein farnesyltransferase complexed with substrates and inhibitors reveal features for antifungal drug design

    OpenAIRE

    Mabanglo, Mark F.; Hast, Michael A.; Lubock, Nathan B; Hellinga, Homme W.; Beese, Lorena S.

    2014-01-01

    Species of the fungal genus Aspergillus are significant human and agricultural pathogens that are often refractory to existing antifungal treatments. Protein farnesyltransferase (FTase), a critical enzyme in eukaryotes, is an attractive potential target for antifungal drug discovery. We report high-resolution structures of A. fumigatus FTase (AfFTase) in complex with substrates and inhibitors. Comparison of structures with farnesyldiphosphate (FPP) bound in the absence or presence of peptide ...

  6. Metabolic pathway of oligosaccharides in sorghum honeydew caused by Claviceps africana Rota metabólica de oligossacarídeos em exsudato da "doença açucarada" do sorgo causado por Claviceps africana

    Directory of Open Access Journals (Sweden)

    Amauri Bogo

    2008-08-01

    Full Text Available The occurrence of the alditol oligosaccharides in the Claviceps afriana honeydew is partly as a rational expression of the pathogen's selective nutritive metabolism of the sucrose supplied by the host plant. The experiments were carried out in laboratory and when 14C-D-sucrose, 14C-D-fructose or 14C-D-mannitol radiolabelled saccharides were incorporated into: a sorghum plant infected by C. africana, b whole and macereted micelia tissue and c cell-free honeydew of C. africana, it was observed that the glucose moiety of sucrose was not involved in oligosaccharides formation. Glucose was used by the pathogen as nutritional source. Part of the unused fructose moiety was reduced to mannitol by the pathogen's enzymes which was also excreted into honeydew where reductase activity accepted 14C mannitol. The mannitol was linked with fructose in a 2-position synthesizing the disaccharide 1-beta-D-fructofuranosyl-D-mannitol and then the process was repeated by the mannitol moiety of the disaccharide to yield the trisaccharide 1,6-di-beta-D-fructofuranosyl-D-mannitol, which became dominant. The direct formation of alditol saccharides from monosaccharides in this way seems to be unique to C. africana, contrasting with the fructosyl transfer from sucrose to sucrose which is usual in others ergot parasites.A ocorrência de oligossacarídeos contendo alditol em exsudações da doença açucarada produzidos por Claviceps africana é em parte uma expressão racional do metabolismo seletivo de nutrição do patógeno na tansformação da sacarose fornecida pela planta. Quando açúcares radioativos marcados com 14C (D-sucrose, D-fructose e D-mannitol foram incorporados em: a planta do sorgo infectada por C. africana, b tecido micelial inteiro e macerado isolado de C. africana e c exsudato livre de células de C. africana, foi observado que a glicose da sacarose não estava envolvida na formação de oligossacarídeos, sendo usada pelo patógeno como fonte

  7. Are bacterial volatile compounds poisonous odors to a fungal pathogen Botrytis cinerea, alarm signals to Arabidopsis seedlings for eliciting induced resistance, or both?

    Directory of Open Access Journals (Sweden)

    Choong-Min eRyu

    2016-02-01

    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

  8. Entomopathogenic fungal endophytes

    Science.gov (United States)

    Fungal endophytes are quite common in nature and some of them have been shown to have adverse effects against insects, nematodes, and plant pathogens. An introduction to fungal endophytes will be presented, followed by a discussion of research aimed at introducing Beauveria bassiana as a fungal endo...

  9. Horizontal transfer of a subtilisin gene from plants into an ancestor of the plant pathogenic fungal genus Colletotrichum.

    Directory of Open Access Journals (Sweden)

    Vinicio Danilo Armijos Jaramillo

    Full Text Available 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.

  10. Horizontal transfer of a subtilisin gene from plants into an ancestor of the plant pathogenic fungal genus Colletotrichum.

    Science.gov (United States)

    Armijos Jaramillo, Vinicio Danilo; Vargas, Walter Alberto; Sukno, Serenella Ana; Thon, Michael R

    2013-01-01

    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.

  11. Impact of the lectin chaperone calnexin on the stress response, virulence and proteolytic secretome of the fungal pathogen Aspergillus fumigatus.

    Directory of Open Access Journals (Sweden)

    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.

  12. Ozone episodes in Southern Lower Saxony (FRG) and their impact on the susceptibility of cereals to fungal pathogens.

    Science.gov (United States)

    von Tiedemann, A; Ostländer, P; Firsching, K H; Fehrmann, H

    1990-01-01

    Spring wheat (Triticum aestivum L.) and spring barley (Hordeum vulgare L.) plants were exposed to simulated ozone (O(3)) episodes (7 h day(-1) for 7 days) at maximum concentrations of 120, 180 and 240 microg m(-3) O(3), in comparison to a charcoal-filtered air control. Fumigations were conducted in four closed chambers placed in a climate room. Exposures took place prior to inoculation of the plants with six different facultative leaf pathogens. On wheat, significant enhancement of leaf attack by Septoria nodorum Berk. and S. tritici Rob. ex Desm. appeared, particularly on the older leaves and at the highest level of O(3). The same was true for Gerlachia nivalis W. Gams et E. Müll/Fusarium culmorum (W.F.Sm.) Sacc. on wheat and net blotch (Drechslera teres (Sacc.) Shoem.) or G. nivalis leaf spots on barley. Disease development was promoted both on leaves with and without visible injury following exposure to O(3). Sporulation of the two Septoria species increased at 120 and 180 microg m(-3) O(3); however, it was reduced to the level of the control, if 240 microg m(-3) were applied. No significant effects of predisposition were observed with Bipolaris sorokiniana (Sacc.) Shoem. (syn. Helminthosporium sativum Pamm., King et Bakke), the causal agent of spot blotch, neither on wheat nor on barley. Doses and peak concentrations applied in the experiments were in good agreement with measurements of ambient ozone in Southern Lower Saxony, FRG. Six years' ozone data (1984-1989) revealed the annual occurrence of between 3 and 11 ozone episodes with potentially harmful effects on cereals (three or more consecutive 'ozone days' with 8-h means above 80 microg m(-3)). The frequency of ozone episodes followed by weather periods favourable for infections by facultative pathogens was higher in years with low O(3) pollution than in ozone-rich years, and varied between one and five cases per season. The number of ozone days during the main growing season of cereals (1 April until 31

  13. Selection of Streptomyces against soil borne fungal pathogens by a standardized dual culture assay and evaluation of their effects on seed germination and plant growth.

    Science.gov (United States)

    Kunova, Andrea; Bonaldi, Maria; Saracchi, Marco; Pizzatti, Cristina; Chen, Xiaoyulong; Cortesi, Paolo

    2016-11-09

    In the search for new natural resources for crop protection, streptomycetes are gaining interest in agriculture as plant growth promoting bacteria and/or biological control agents. Because of their peculiar life cycle, in which the production of secondary metabolites is synchronized with the development of aerial hyphae and sporulation, the commonly used methods to screen for bacterial antagonists need to be adapted. The dual culture assay was standardized in terms of inoculation timing of Streptomyces antagonist and pathogen, and growth rate of different fungal pathogens. In case of fast-growing fungi, inoculation of the antagonist 2 or 3 days prior to the pathogen resulted in significantly stronger inhibition of mycelium growth. One hundred and thirty Streptomyces strains were evaluated against six destructive soil borne pathogens. The activity of strains varied from broad-spectrum to highly specific inhibition of individual pathogens. All strains inhibited at least one tested pathogen. Three strains, which combined the largest broad-spectrum with the highest inhibition activity, were selected for further characterization with four vegetable species. All of them were able to colonize seed surface of all tested vegetable crops. They mostly improved radicle and hypocotyl growth in vitro, although no statistically significant enhancement of biomass weight was observed in vivo. Occasionally, transient negative effects on germination and plant growth were observed. The adapted dual culture assay allowed us to compare the inhibition of individual Streptomyces strains against six fungal soil borne pathogens. The best selected strains were able to colonize the four vegetable crops and have a potential to be developed into biocontrol products. Although they occasionally negatively influenced plant growth, these effects did not persist during the further development. Additional in vivo studies are needed to confirm their potential as biological control or plant growth

  14. Phylogenetic evidence for an animal pathogen origin of ergot and the grass endophytes.

    Science.gov (United States)

    Spatafora, J W; Sung, G-H; Sung, J-M; Hywel-Jones, N L; White, J F

    2007-04-01

    Grass-associated fungi (grass symbionts) in the family Clavicipitaceae (Ascomycota, Hypocreales) are species whose host range is restricted to the plant family Poaceae and rarely Cyperaceae. The best-characterized species include Claviceps purpurea (ergot of rye) and Neotyphodium coenophialum (endophyte of tall fescue). They have been the focus of considerable research due to their importance in agricultural and grassland ecosystems and the diversity of their bioactive secondary metabolites. Here we show through multigene phylogenetic analyses and ancestral character state reconstruction that the grass symbionts in Clavicipitaceae are a derived group that originated from an animal pathogen through a dynamic process of interkingdom host jumping. The closest relatives of the grass symbionts include the genera Hypocrella, a pathogen of scale insects and white flies, and Metarhizium, a generalist arthropod pathogen. These data do not support the monophyly of Clavicipitaceae, but place it as part of a larger clade that includes Hypocreaceae, a family that contains mainly parasites of other fungi. A minimum of 5-8 independent and unidirectional interkingdom host jumps has occurred among clavicipitaceous fungi, including 3-5 to fungi, 1-2 to animals, and 1 to plants. These findings provide a new evolutionary context for studying the biology of the grass symbionts, their role in plant ecology, and the evolution of host affiliation in fungal symbioses.

  15. Genome-wide profiling of DNA methylation provides insights into epigenetic regulation of fungal development in a plant pathogenic fungus, Magnaporthe oryzae.

    Science.gov (United States)

    Jeon, Junhyun; Choi, Jaeyoung; Lee, Gir-Won; Park, Sook-Young; Huh, Aram; Dean, Ralph A; Lee, Yong-Hwan

    2015-02-24

    DNA methylation is an important epigenetic modification that regulates development of plants and mammals. To investigate the roles of DNA methylation in fungal development, we profiled genome-wide methylation patterns at single-nucleotide resolution during vegetative growth, asexual reproduction, and infection-related morphogenesis in a model plant pathogenic fungus, Magnaporthe oryzae. We found that DNA methylation occurs in and around genes as well as transposable elements and undergoes global reprogramming during fungal development. Such reprogramming of DNA methylation suggests that it may have acquired new roles other than controlling the proliferation of TEs. Genetic analysis of DNA methyltransferase deletion mutants also indicated that proper reprogramming in methylomes is required for asexual reproduction in the fungus. Furthermore, RNA-seq analysis showed that DNA methylation is associated with transcriptional silencing of transposable elements and transcript abundance of genes in context-dependent manner, reinforcing the role of DNA methylation as a genome defense mechanism. This comprehensive approach suggests that DNA methylation in fungi can be a dynamic epigenetic entity contributing to fungal development and genome defense. Furthermore, our DNA methylomes provide a foundation for future studies exploring this key epigenetic modification in fungal development and pathogenesis.

  16. The endosymbiont Arsenophonus is widespread in soybean aphid, Aphis glycines, but does not provide protection from parasitoids or a fungal pathogen.

    Directory of Open Access Journals (Sweden)

    Jason A Wulff

    Full Text Available Aphids commonly harbor bacterial facultative symbionts that have a variety of effects upon their aphid hosts, including defense against hymenopteran parasitoids and fungal pathogens. The soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae, is infected with the symbiont Arsenophonus sp., which has an unknown role in its aphid host. Our research goals were to document the infection frequency and diversity of the symbiont in field-collected soybean aphids, and to determine whether Arsenophonus is defending soybean aphid against natural enemies. We performed diagnostic PCR and sequenced four Arsenophonus genes in soybean aphids from their native and introduced range to estimate infection frequency and genetic diversity, and found that Arsenophonus infection is highly prevalent and genetically uniform. To evaluate the defensive role of Arsenophonus, we cured two aphid genotypes of their natural Arsenophonus infection through ampicillin microinjection, resulting in infected and uninfected isolines within the same genetic background. These isolines were subjected to parasitoid assays using a recently introduced biological control agent, Binodoxys communis [Braconidae], a naturally recruited parasitoid, Aphelinus certus [Aphelinidae], and a commercially available biological control agent, Aphidius colemani [Braconidae]. We also assayed the effect of the common aphid fungal pathogen, Pandora neoaphidis (Remaudiere & Hennebert Humber (Entomophthorales: Entomophthoraceae, on the same aphid isolines. We did not find differences in successful parasitism for any of the parasitoid species, nor did we find differences in P. neoaphidis infection between our treatments. Our conclusion is that Arsenophonus does not defend its soybean aphid host against these major parasitoid and fungal natural enemies.

  17. [Organization and preservation of the collection of pathogenic and fungal symbionts of insects and other arthropods from CEPAVE (CONICET-UNLP), La Plata, Argentina].

    Science.gov (United States)

    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.

  18. Evidence of threat to European economy and biodiversity following the introduction of an alien pathogen on the fungal-animal boundary.

    Science.gov (United States)

    Ercan, Didem; Andreou, Demetra; Sana, Salma; Öntaş, Canan; Baba, Esin; Top, Nildeniz; Karakuş, Uğur; Tarkan, Ali Serhan; Gozlan, Rodolphe Elie

    2015-09-02

    Recent years have seen a global and rapid resurgence of fungal diseases with direct impact on biodiversity and local extinctions of amphibian, coral, or bat populations. Despite similar evidence of population extinction in European fish populations and the associated risk of food aquaculture due to the emerging rosette agent Sphaerothecum destruens, an emerging infectious eukaryotic intracellular pathogen on the fungal-animal boundary, our understanding of current threats remained limited. Long-term monitoring of population decline for the 8-year post-introduction of the fungal pathogen was coupled with seasonal molecular analyses of the 18S rDNA and histological work of native fish species organs. A phylogenetic relationship between the existing EU and US strains using the ribosomal internal transcribed spacer sequences was also carried out. Here, we provide evidence that this emerging parasite has now been introduced via Pseudorasbora parva to sea bass farms, an industry that represents over 400 M€€ annually in a Mediterranean region that is already economically vulnerable. We also provide for the first time evidence linking S. destruens to disease and severe declines in International Union for Conservation of Nature threatened European endemic freshwater fishes (i.e. 80% to 90 % mortalities). Our findings are thus of major economic and conservation importance.

  19. Agrobacterium-mediated transformation of tomato with rolB gene results in enhancement of fruit quality and foliar resistance against fungal pathogens.

    Science.gov (United States)

    Arshad, Waheed; Haq, Ihsan-ul-; Waheed, Mohammad Tahir; Mysore, Kirankumar S; Mirza, Bushra

    2014-01-01

    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.

  20. Plant small monomeric G-proteins (RAC/ROPs) of barley are common elements of susceptibility to fungal leaf pathogens, cell expansion and stomata development.

    Science.gov (United States)

    Pathuri, Indira Priyadarshini; Eichmann, Ruth; Hückelhoven, Ralph

    2009-02-01

    Small monomeric RAC/ROP GTPases act as molecular switches in signal transduction processes of plant development and stress responses. They emerged as crucial players in plant-pathogen interactions either by supporting susceptibility or resistance. In a recent publication, we showed that constitutively activated (CA) mutants of different barley (Hordeum vulgare) RAC/ROPs regulate susceptibility to barley fungal leaf pathogens of different life style in a contrasting way. This illustrates the distinctive signalling roles of RAC/ROPs for different plant-pathogen combinations. We also reported the involvement of RAC/ROPs in plant epidermis development in a monocotyledonous plant. Here we further discuss a failure of CA HvRAC/ROP-expressing barley to normally develop stomata.

  1. Interaction of cruciferous phytoanticipins with plant fungal pathogens: indole glucosinolates are not metabolized but the corresponding desulfo-derivatives and nitriles are.

    Science.gov (United States)

    Pedras, M Soledade C; Hossain, Sajjad

    2011-12-01

    Glucosinolates represent a large group of plant natural products long known for diverse and fascinating physiological functions and activities. Despite the relevance and huge interest on the roles of indole glucosinolates in plant defense, little is known about their direct interaction with microbial plant pathogens. Toward this end, the metabolism of indolyl glucosinolates, their corresponding desulfo-derivatives, and derived metabolites, by three fungal species pathogenic on crucifers was investigated. While glucobrassicin, 1-methoxyglucobrassicin, 4-methoxyglucobrassicin were not metabolized by the pathogenic fungi Alternaria brassicicola, Rhizoctonia solani and Sclerotinia sclerotiorum, the corresponding desulfo-derivatives were metabolized to indolyl-3-acetonitrile, caulilexin C (1-methoxyindolyl-3-acetonitrile) and arvelexin (4-methoxyindolyl-3-acetonitrile) by R. solani and S. sclerotiorum, but not by A. brassicicola. That is, desulfo-glucosinolates were metabolized by two non-host-selective pathogens, but not by a host-selective. Indolyl-3-acetonitrile, caulilexin C and arvelexin were metabolized to the corresponding indole-3-carboxylic acids. Indolyl-3-acetonitriles displayed higher inhibitory activity than indole desulfo-glucosinolates. Indolyl-3-methanol displayed antifungal activity and was metabolized by A. brassicicola and R. solani to the less antifungal compounds indole-3-carboxaldehyde and indole-3-carboxylic acid. Diindolyl-3-methane was strongly antifungal and stable in fungal cultures, but ascorbigen was not stable in solution and displayed low antifungal activity; neither compound appeared to be metabolized by any of the three fungal species. The cell-free extracts of mycelia of A. brassicicola displayed low myrosinase activity using glucobrassicin as substrate, but myrosinase activity was not detectable in mycelia of either R. solani or S. sclerotiorum. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Proteome of cell wall-extracts from pathogenic Paracoccidioides brasiliensis: Comparison among morphological phases, isolates, and reported fungal extracellular vesicle proteins

    Directory of Open Access Journals (Sweden)

    Larissa V.G. Longo

    2014-06-01

    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.

  3. PKC signaling regulates drug resistance of the fungal pathogen Candida albicans via circuitry comprised of Mkc1, calcineurin, and Hsp90.

    Directory of Open Access Journals (Sweden)

    Shantelle L LaFayette

    Full Text Available Fungal pathogens exploit diverse mechanisms to survive exposure to antifungal drugs. This poses concern given the limited number of clinically useful antifungals and the growing population of immunocompromised individuals vulnerable to life-threatening fungal infection. To identify molecules that abrogate resistance to the most widely deployed class of antifungals, the azoles, we conducted a screen of 1,280 pharmacologically active compounds. Three out of seven hits that abolished azole resistance of a resistant mutant of the model yeast Saccharomyces cerevisiae and a clinical isolate of the leading human fungal pathogen Candida albicans were inhibitors of protein kinase C (PKC, which regulates cell wall integrity during growth, morphogenesis, and response to cell wall stress. Pharmacological or genetic impairment of Pkc1 conferred hypersensitivity to multiple drugs that target synthesis of the key cell membrane sterol ergosterol, including azoles, allylamines, and morpholines. Pkc1 enabled survival of cell membrane stress at least in part via the mitogen activated protein kinase (MAPK cascade in both species, though through distinct downstream effectors. Strikingly, inhibition of Pkc1 phenocopied inhibition of the molecular chaperone Hsp90 or its client protein calcineurin. PKC signaling was required for calcineurin activation in response to drug exposure in S. cerevisiae. In contrast, Pkc1 and calcineurin independently regulate drug resistance via a common target in C. albicans. We identified an additional level of regulatory control in the C. albicans circuitry linking PKC signaling, Hsp90, and calcineurin as genetic reduction of Hsp90 led to depletion of the terminal MAPK, Mkc1. Deletion of C. albicans PKC1 rendered fungistatic ergosterol biosynthesis inhibitors fungicidal and attenuated virulence in a murine model of systemic candidiasis. This work establishes a new role for PKC signaling in drug resistance, novel circuitry through which

  4. Aortoventricular Dissociation and Refractory Fungal Endocarditis Caused by a Rare Pathogen Lichtheimia: A Surgical and Medical Management Strategy.

    Science.gov (United States)

    Terrien, Christopher M; Edwards, Niloo M

    2017-01-01

    We report a rare case of prosthetic valve fungal endocarditis caused by Lichtheimia, a subspecies of the order Mucorales. The patient experienced complicated prosthetic valve endocarditis less than 2 months after uneventful coronary artery bypass grafting (CABG) and 2 aortic valve replacements. Ultimately surgical management required aortic root replacement and lifelong antimicrobial agents. We believe this is the first case of fungal endocarditis caused by Lichtheimia. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  5. Cytosolic free calcium dynamics as related to hyphal and colony growth in the filamentous fungal pathogen Colletotrichum graminicola.

    Science.gov (United States)

    Lange, Mario; Peiter, Edgar

    2016-06-01

    Tip growth of pollen tubes and root hairs of plants is oscillatory and orchestrated by tip-focussed variations of cytosolic free calcium ([Ca(2+)]cyt). Hyphae of filamentous fungi are also tubular tip-growing cells, and components of the Ca(2+) signalling machinery, such as Ca(2+) channels and Ca(2+) sensors, are known to be important for fungal growth. In this study, we addressed the questions if tip-focussed [Ca(2+)]cyt transients govern hyphal and whole-colony growth in the maize pathogen Colletotrichum graminicola, and whether colony-wide [Ca(2+)]cyt dynamics rely on external Ca(2+) or internal Ca(2+) stores. Ratiometric fluorescence microscopy of individual hyphae expressing the Ca(2+) reporter Yellow Cameleon 3.6 revealed that Ca(2+) spikes in hyphal tips precede the re-initiation of growth after wounding. Tip-focussed [Ca(2+)]cyt spikes were also observed in undisturbed growing hyphae. They occurred not regularly and at a higher rate in hyphae growing at a medium-glass interface than in those growing on an agar surface. Hyphal tip growth was non-pulsatile, and growth speed was not correlated with the rate of spike occurrence. A possible relationship of [Ca(2+)]cyt spike generation and growth of whole colonies was assessed by using a codon-optimized version of the luminescent Ca(2+) reporter Aequorin. Depletion of extracellular free Ca(2+) abolished [Ca(2+)]cyt spikes nearly completely, but had only a modest effect on colony growth. In a pharmacological survey, some inhibitors targeting Ca(2+) influx or release from internal stores repressed growth strongly. However, although some of those inhibitors also affected [Ca(2+)]cyt spike generation, the effects on both parameters were not correlated. Collectively, the results indicate that tip growth of C. graminicola is non-pulsatile and not mechanistically linked to tip-focused or global [Ca(2+)]cyt spikes, which are likely a response to micro-environmental parameters, such as the physical properties of the

  6. New insights into the in vitro development and virulence of Culicinomyces spp. as fungal pathogens of Aedes aegypti.

    Science.gov (United States)

    Rodrigues, Juscelino; Luz, Christian; Humber, Richard A

    2017-03-31

    Culicinomyces spp. (Hypocreales: Cordycipitaceae) are facultative fungal pathogens affecting the larval stages from a range of mosquito species and are especially notable in their ability to infect hosts through the digestive tract after conidial ingestion. While Culicinomyces spp. were studied mainly in the 1980s, little is yet known about inter- and intraspecific variability of the in vitro development of these fungi at different temperatures, and nothing is known about the impact of serial host-passage on the development or virulence against Aedes aegypti larvae. The development of ten isolates of C. clavisporus (ARSEF 372, 582, 644, 706, 964, 1260, 2471, 2478, 2479 and 2480) and one of C. bisporalis (ARSEF 1948) was assessed on solid SDAY/4 and liquid SDY/4 at 15, 20, 25, 30 and 35°C. Based on the results of these assays, three isolates were selected (ARSEF 644, 964 and 2479) for three serial host-passage/reisolation cycles, and comparison of the reisolates with the original stock isolates for their virulence, vegetative growth and conidiogenesis. The highest germination rates (≥95%) after 48h incubation were obtained at 25 and 20°C, and the lowest germination (≤12%) at 35°C after the same time. The optimal temperature for radial growth was 25°C (≥11.8mm), followed by 20°C for all isolates. ARSEF 706, 582 and 372 showed the greatest vegetative growth (≥20mm). In general, there was little radial growth of colonies at 30°C (≤2.5mm), and none at 35°C. Isolates, especially ARSEF 964, 2479, and 644, generally produced the highest numbers of conidia at 25°C (≥1.42×10(5) conidia/plate) after 15days. After two host-passages, conidiogenesis increased significantly on SDAY/4 for ARSEF 2479 but not for ARSEF 644 or 964. All larvae exposed to these three isolates of C. clavisporus died within 7days regardless of the concentration or host-passage; C. bisporalis was not tested in these experiments. The virulence of ARSEF 964 increased at lower

  7. Arabidopsis Elongator subunit 2 positively contributes to resistance to the necrotrophic fungal pathogens Botrytis cinerea and Alternaria brassicicola.

    Science.gov (United States)

    Wang, Chenggang; Ding, Yezhang; Yao, Jin; Zhang, Yanping; Sun, Yijun; Colee, James; Mou, Zhonglin

    2015-09-01

    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.

  8. Biology, genetics, and management of ergot (Claviceps spp.) in rye, sorghum, and pearl millet.

    Science.gov (United States)

    Miedaner, Thomas; Geiger, Hartwig H

    2015-02-25

    Ergot is a disease of cereals and grasses caused by fungi in the genus Claviceps. Of particular concern are Claviceps purpurea in temperate regions, C. africana in sorghum (worldwide), and C. fusiformis in pearl millet (Africa, Asia). The fungi infect young, usually unfertilized ovaries, replacing the seeds by dark mycelial masses known as sclerotia. The percentage of sclerotia in marketable grain is strictly regulated in many countries. In winter rye, ergot has been known in Europe since the early Middle Ages. The alkaloids produced by the fungus severely affect the health of humans and warm-blooded animals. In sorghum and pearl millet, ergot became a problem when growers adopted hybrid technology, which increased host susceptibility. Plant traits reducing ergot infection include immediate pollination of receptive stigmas, closed flowering (cleistogamy), and physiological resistance. Genetic, nonpollen-mediated variation in ergot susceptibility could be demonstrated in all three affected cereals. Fungicides have limited efficacy and application is weather dependent. Sorting out the sclerotia from the harvest by photocells is expensive and time consuming. In conclusion, molecular-based hybrid rye breeding could improve pollen fertility by introgressing effective restorer genes thus bringing down the ergot infection level to that of conventional population cultivars. A further reduction might be feasible in the future by selecting more resistant germplasm.

  9. Antagonistic potentiality of Trichoderma harzianum towards seed-borne fungal pathogens of winter wheat cv. Protiva in vitro and in vivo.

    Science.gov (United States)

    Hasan, M M; Rahman, S M E; Kim, Gwang-Hee; Abdallah, Elgorban; Oh, Deog-Hwan

    2012-05-01

    The antagonistic effect of Trichoderma harzianum on a range of seed-borne fungal pathogens of wheat (viz. Fusarium graminearum, Bipolaris sorokiniana, Aspergillus spp., and Penicillium spp.) was assessed. The potential of T. harzianum as a biocontrol agent was tested in vitro and under field conditions. Coculture of the pathogens and Trichoderma under laboratory conditions clearly showed dominance of T. harzianum. Under natural conditions, biocontrol effects were also obtained against the test fungi. One month after sowing, field emergence (plant stand) was increased by 15.93% over that obtained with the control treatment, and seedling infection was reduced significantly. Leaf blight severity was decreased from 22 to 11 at the heading stage, 35 to 31 at the flowering stage, and 86 to 74 at the grain filling stage. At harvest, the number of tillers per plant was increased by 50%, the yield was increased by 31.58%, and the 1,000-seed weight was increased by 21%.

  10. Polyphenols Variation in Fruits of the Susceptible Strawberry Cultivar Alba during Ripening and upon Fungal Pathogen Interaction and Possible Involvement in Unripe Fruit Tolerance.

    Science.gov (United States)

    Nagpala, Ellaine Grace; Guidarelli, Michela; Gasperotti, Mattia; Masuero, Domenico; Bertolini, Paolo; Vrhovsek, Urska; Baraldi, Elena

    2016-03-09

    Strawberry (Fragaria × ananassa) fruit contains high concentrations of health-promoting phenolic compounds, playing important roles for the fruit ontogenic tolerance to fungi. In the highly susceptible cultivar Alba, the two major strawberry fungal pathogens, Colletotrichum acutatum and Botrytis cinerea, displayed disease symptoms only at red ripe stages because immature fruits are tolerant to diseases. We analyzed and compared the variation of 47 polyphenols in the surface of unripe and ripe Alba fruits upon 24 and 48 h of C. acutatum and B. cinerea infection or mock inoculation. Significant alteration in phenolic content was detected only in white infected fruit, with differences specific for each pathogen. The expression analysis of phenylpropanoid, flavonoid, and shikimate pathway genes showed in only a few cases correlation with the relative metabolite abundance. The alteration in phenolic content and the lack of consistency with gene expression data are discussed in light of previously reported metabolome data of different susceptible and resistant strawberry genotypes.

  11. IRIDOID GLYCOSIDES FROM LINARIA GENISTIFOLIA (L. MILL. IN BIOLOGICAL CONTROL OF SOIL-BORNE FUNGAL PATHOGENS OF WHEAT AND SOME STRUCTURE CONSIDERATIONS

    Directory of Open Access Journals (Sweden)

    Natalia Mashcenko

    2015-06-01

    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.

  12. Identification and expression analysis of WRKY transcription factor genes in canola (Brassica napus L. in response to fungal pathogens and hormone treatments

    Directory of Open Access Journals (Sweden)

    Deyholos Michael K

    2009-06-01

    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

  13. Identification and Evaluation of Novel Drug Targets against the Human Fungal Pathogen Aspergillus fumigatus with Elaboration on the Possible Role of RNA-Binding Protein

    Science.gov (United States)

    Malekzadeh, Saeid; Sardari, Soroush; Azerang, Parisa; Khorasanizadeh, Dorsa; Amiri, Solmaz Agha; Azizi, Mohammad; Mohajerani, Nazanin; Khalaj, Vahid

    2017-01-01

    Bakground: Aspergillus fumigatus is an airborne opportunistic fungal pathogen that can cause fatal infections in immunocompromised patients. Although the current anti-fungal therapies are relatively efficient, some issues such as drug toxicity, drug interactions, and the emergence of drug-resistant fungi have promoted the intense research toward finding the novel drug targets. Methods: In search of new antifungal drug targets, we have used a bioinformatics approach to identify novel drug targets. We compared the whole proteome of this organism with yeast Saccharomyces cerevisiae to come up with 153 specific proteins. Further screening of these proteins revealed 50 potential molecular targets in A. fumigatus. Amongst them, RNA-binding protein (RBP) was selected for further examination. The aspergillus fumigatus RBP (AfuRBP), as a peptidylprolyl isomerase, was evaluated by homology modeling and bioinformatics tools. RBP-deficient mutant strains of A. fumigatus were generated and characterized. Furthermore, the susceptibility of these strains to known peptidylprolyl isomerase inhibitors was assessed. Results: AfuRBP-deficient mutants demonstrated a normal growth phenotype. MIC assay results using inhibitors of peptidylprolyl isomerase confirmed a higher sensitivity of these mutants compared to the wild type. Conclusion: Our bioinformatics approach revealed a number of fungal-specific proteins that may be considered as new targets for drug discovery purposes. Peptidylprolyl isomerase, as a possible drug target, was evaluated against two potential inhibitors, and the promising results were investigated mechanistically. Future studies would confirm the impact of such target on the antifungal discovery investigations PMID:28000798

  14. Anti-proliferative effect of fungal taxol extracted from Cladosporium oxysporum against human pathogenic bacteria and human colon cancer cell line HCT 15

    Science.gov (United States)

    Gokul Raj, K.; Manikandan, R.; Arulvasu, C.; Pandi, M.

    2015-03-01

    Cladosporium oxysporum a new taxol producing endophytic fungus was identified and production of taxol were characterized using UV-visible spectroscopy (UV-vis), high-performance liquid chromatography (HPLC), infrared (IR) nuclear magnetic resonance spectroscopy (NMR (13C and 1H)) and liquid chromatography-mass spectrometry (LC-MS). The taxol biosynthetic gene (dbat) was evaluated for new taxol producing fungus. Antibacterial activity against six different human pathogenic bacteria was done by agar well diffusion method. The anticancer efficacy of isolated fungal taxol were also evaluated in human colon cancer cell HCT 15 by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), cytotoxicity and nuclear morphology analysis. The isolated fungal taxol showed positive towards biosynthetic gene (dbat) and effective against both Gram positive as well as Gram negative. The fungal taxol suppress growth of cancer cell line HCT 15 with an IC50 value of 3.5 μM concentration by 24 h treatment. Thus, the result reveals that C. oxysporum could be a potential alternative source for production of taxol and have antibacterial as well as anticancer properties with possible clinical applications.

  15. The fungal pathogen Moniliophthora perniciosa has genes similar to plant PR-1 that are highly expressed during its interaction with cacao.

    Directory of Open Access Journals (Sweden)

    Paulo J P L Teixeira

    Full Text Available The widespread SCP/TAPS superfamily (SCP/Tpx-1/Ag5/PR-1/Sc7 has multiple biological functions, including roles in the immune response of plants and animals, development of male reproductive tract in mammals, venom activity in insects and reptiles and host invasion by parasitic worms. Plant Pathogenesis Related 1 (PR-1 proteins belong to this superfamily and have been characterized as markers of induced defense against pathogens. This work presents the characterization of eleven genes homologous to plant PR-1 genes, designated as MpPR-1, which were identified in the genome of Moniliophthora perniciosa, a basidiomycete fungus responsible for causing the devastating witches' broom disease in cacao. We describe gene structure, protein alignment and modeling analyses of the MpPR-1 family. Additionally, the expression profiles of MpPR-1 genes were assessed by qPCR in different stages throughout the fungal life cycle. A specific expression pattern was verified for each member of the MpPR-1 family in the conditions analyzed. Interestingly, some of them were highly and specifically expressed during the interaction of the fungus with cacao, suggesting a role for the MpPR-1 proteins in the infective process of this pathogen. Hypothetical functions assigned to members of the MpPR-1 family include neutralization of plant defenses, antimicrobial activity to avoid competitors and fruiting body physiology. This study provides strong evidence on the importance of PR-1-like genes for fungal virulence on plants.

  16. A rapid genotyping method for an obligate fungal pathogen, Puccinia striiformis f.sp. tritici, based on DNA extraction from infected leaf and Multiplex PCR genotyping

    Directory of Open Access Journals (Sweden)

    Enjalbert Jérôme

    2011-07-01

    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.

  17. Agrobacterium tumefaciens-mediated transformation of taro (Colocasia esculenta (L.) Schott) with a rice chitinase gene for improved tolerance to a fungal pathogen Sclerotium rolfsii.

    Science.gov (United States)

    He, Xiaoling; Miyasaka, Susan C; Fitch, Maureen M M; Moore, Paul H; Zhu, Yun J

    2008-05-01

    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.

  18. The fungal pathogen Moniliophthora perniciosa has genes similar to plant PR-1 that are highly expressed during its interaction with cacao.

    Science.gov (United States)

    Teixeira, Paulo J P L; Thomazella, Daniela P T; Vidal, Ramon O; do Prado, Paula F V; Reis, Osvaldo; Baroni, Renata M; Franco, Sulamita F; Mieczkowski, Piotr; Pereira, Gonçalo A G; Mondego, Jorge M C

    2012-01-01

    The widespread SCP/TAPS superfamily (SCP/Tpx-1/Ag5/PR-1/Sc7) has multiple biological functions, including roles in the immune response of plants and animals, development of male reproductive tract in mammals, venom activity in insects and reptiles and host invasion by parasitic worms. Plant Pathogenesis Related 1 (PR-1) proteins belong to this superfamily and have been characterized as markers of induced defense against pathogens. This work presents the characterization of eleven genes homologous to plant PR-1 genes, designated as MpPR-1, which were identified in the genome of Moniliophthora perniciosa, a basidiomycete fungus responsible for causing the devastating witches' broom disease in cacao. We describe gene structure, protein alignment and modeling analyses of the MpPR-1 family. Additionally, the expression profiles of MpPR-1 genes were assessed by qPCR in different stages throughout the fungal life cycle. A specific expression pattern was verified for each member of the MpPR-1 family in the conditions analyzed. Interestingly, some of them were highly and specifically expressed during the interaction of the fungus with cacao, suggesting a role for the MpPR-1 proteins in the infective process of this pathogen. Hypothetical functions assigned to members of the MpPR-1 family include neutralization of plant defenses, antimicrobial activity to avoid competitors and fruiting body physiology. This study provides strong evidence on the importance of PR-1-like genes for fungal virulence on plants.

  19. Functional analysis of CLPT1, a Rab/GTPase required for protein secretion and pathogenesis in the plant fungal pathogen Colletotrichum lindemuthianum.

    Science.gov (United States)

    Siriputthaiwan, Piyawan; Jauneau, Alain; Herbert, Corentin; Garcin, Daphné; Dumas, Bernard

    2005-01-15

    In eukaryotic cells, Rab/GTPases are major regulators of vesicular trafficking and are involved in essential processes including exocytosis, endocytosis and cellular differentiation. To investigate the role of these proteins in fungal pathogenicity, a dominant-negative mutant allele of CLPT1, a Rab/GTPase of the bean pathogen Colletotrichum lindemuthianum, was expressed in transgenic strains. This mutated gene encodes the amino-acid substitution N123I analogous to the N133I substitution in a known trans-dominant inhibitor of the Sec4 Rab/GTPase from Saccharomyces cerevisiae. A pectinase gene promoter was used to drive the CLPT1(N123I) allele in C. lindemuthianum, allowing the expression of the foreign gene on pectin medium and during pathogenesis, but not on glucose. The same strategy was used to overexpress the wild-type CLPT1 allele. During growth on pectin medium, production of extracellular pectinases was strongly impaired only in CLPT1(N123I)-expressing strains. Cytological analysis revealed that CLPT1(N123I) strains accumulated intracellular aggregates only on pectin, resulting from the fusion of vesicles containing polysaccharides or glycoproteins. Moreover, these strains showed a severe reduction of pathogenesis and were unable to penetrate the host cells. These results indicated that the Rab/GTPase CLPT1 is essential for fungal pathogenesis by regulating the intracellular transport of secretory vesicles involved in the delivery of proteins to the extracellular medium and differentiation of infectious structures.

  20. Photosynthesis-dependent physiological and genetic crosstalk between cold acclimation and cold-induced resistance to fungal pathogens in triticale (Triticosecale Wittm.).

    Science.gov (United States)

    Szechyńska-Hebda, Magdalena; Wąsek, Iwona; Gołębiowska-Pikania, Gabriela; Dubas, Ewa; Żur, Iwona; Wędzony, Maria

    2015-04-01

    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

  1. Plant volatiles cause direct, induced and associational resistance in common bean to the fungal pathogen Colletotrichum lindemuthianum

    National Research Council Canada - National Science Library

    Quintana‐Rodriguez, Elizabeth; Morales‐Vargas, Adan T; Molina‐Torres, Jorge; Ádame‐Alvarez, Rosa M; Acosta‐Gallegos, Jorge A; Heil, Martin; Flynn, Dan

    2015-01-01

    ... ( Phaseolus vulgaris ) cultivar enhance the resistance to the fungus Colletotrichum lindemuthianum in a susceptible cultivar and analysed whether specific VOC s are likely to directly affect the pathogen...

  2. Real-time PCR for detection and quantification of fungal and oomycete tomato pathogens in plant and soil samples

    NARCIS (Netherlands)

    Lievens, B.; Brouwer, M.; Vanachter, A.C.R.C.; Cammue, B.P.A.; Thomma, B.P.H.J.

    2006-01-01

    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 straigh

  3. Real-time PCR for detection and quantification of fungal and oomycete tomato pathogens in plant and soil samples

    NARCIS (Netherlands)

    Lievens, B.; Brouwer, M.; Vanachter, A.C.R.C.; Cammue, B.P.A.; Thomma, B.P.H.J.

    2006-01-01

    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 straigh

  4. Finished Genome of the Fungal Wheat Pathogen Mycosphaerella graminicola Reveals Dispensome Structure, Chromosome Plasticity, and Stealth Pathogenesis

    NARCIS (Netherlands)

    Goodwin, S.B.; Ben M'Barek, S.; Dhillon, B.; Wittenberg, A.H.J.; Crane, C.F.; Hane, J.K.; Foster, A.J.; van der Lee, T.A.J.; Grimwood, J.; Aerts, A.; Antoniw, J.; Bailey, A.; Bluhm, B.; Bowler, J.M.; Bristow, J.; van der Burgt, A.; Canto-Canché, B.; Churchill, A.C.L.; Conde-Ferràez, L.; Cools, H.J.; Coutinho, P.M.; Csukai, M.; Dehal, P.; de Wit, P.; Donzelli, B.; Geest, H.G.; van Ham, R.C.H.; Hammond-Kosack, K.E.; Henrissat, B.; Kilian, A.; Kobayashi, A.K.; Koopmann, E.; Kourmpetis, Y.; Kuzniar, A.; Lindquist, E.; Lombard, V.; Maliepaard, C.; Martins, N.; Mehrabi, R.; Nap, J.P.H.; Ponomarenko, A.; Rudd, J.J.; Salamov, A.; Schmutz, J.; Schouten, H.J.; Shapiro, H.; Stergiopoulos, I.; Torriani, S.F.F.; Tu, H.; de Vries, R.P.; Waalwijk, C.; Ware, S.B.; Wiebenga, A.; Zwiers, L.H.; Oliver, R.P.; Grigoriev, I.V.; Kema, G.H.J.

    2011-01-01

    The plant-pathogenic fungus Mycosphaerella graminicola causes septoria tritici blotch, one of the most economically important diseases of wheat worldwide and a potential threat to global food production. Unlike most other plant pathogens, M. graminicola has a long latent period during which it seems

  5. The hijacking of a receptor kinase-driven pathway by a wheat fungal pathogen leads to disease

    Science.gov (United States)

    Necrotrophic pathogens live and feed on dying tissue, but their interactions with plants are not well understood compared to biotrophic and hemibiotrophic pathogens. Here, we report the positional cloning of the wheat gene, Snn1, a member of the wall-associated kinase class of receptors, which are ...

  6. Colletotrichum truncatum species complex: Treatment considerations and review of the literature for an unusual pathogen causing fungal keratitis and endophthalmitis

    Directory of Open Access Journals (Sweden)

    Victoria Squissato

    2015-09-01

    Full Text Available We present a case of Colletotrichum truncatum species complex fungal keratitis and endophthalmitis in an 87-year-old immunocompetent male in whom oral triazole antifungals were contraindicated. The patient had recently returned from 4 months in Jamaica with a one month history of progressively increasing pain and inflammation in his left eye. Corneal samples grew a filamentous fungus and internal transcribed spacer sequencing polymerase chain reaction confirmed the presence of C. truncatum species complex. Samples showed no microbial growth.

  7. Post-genomic analyses of fungal lignocellulosic biomass degradation reveal the unexpected potential of the plant pathogen Ustilago maydis

    Directory of Open Access Journals (Sweden)

    Couturier Marie

    2012-02-01

    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.

  8. Genetic structure and parasitization-related ability divergence of a nematode fungal pathogen Hirsutella minnesotensis following founder effect in China.

    Science.gov (United States)

    Shu, Chi; Jiang, Xianzhi; Cheng, Xiaoli; Wang, Niuniu; Chen, Senyu; Xiang, Meichun; Liu, Xingzhong

    2015-08-01

    The fungal parasitoid, Hirsutella minnesotensis, is a dominant parasitoid of the soybean cyst nematode, which is a destruction pest of soybean crops. We investigated population structure and parasitism pattern in samples of H. minnesotensis in China to reveal the spreading pattern of this fungal species and the underlying mechanism generating the parasitization-related ability variability in Chinese population. In cross-inoculation experiments using different combinations of H. minnesotensis and soybean cyst nematode samples from China, most H. minnesotensis isolates fitted the criterion for "local versus foreign" parasitism profile, exhibiting local adaptation pattern to the SCN host. However, the genetic analysis of the single nucleotide polymorphisms with clone-corrected samples based on ten DNA fragments in 56 isolates of H. minnesotensis from China revealed that the Chinese H. minnesotensis population was a clonal lineage that underwent a founder event. The results demonstrated that the Chinese H. minnesotensis population had generated parasitization-related ability diversity after a founder event through individual variation or phenotypic plasticity other than local adaptation. The rapid divergence of parasitization-related abilities with simple genetic structure in Chinese H. minnesotensis population indicates a fundamental potential for the establishment of invasive fungal species, which is a prerequisite for biological control agents.

  9. Potential for Combined Biocontrol Activity against Fungal Fish and Plant Pathogens by Bacterial Isolates from a Model Aquaponic System

    Directory of Open Access Journals (Sweden)

    Ivaylo Sirakov

    2016-11-01

    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.

  10. Scaling up tests on virulence of the cassava green mite fungal pathogen Neozygites tanajoae (Entomophthorales: Neozygitaceae) under controlled conditions: first observations at the population level.

    Science.gov (United States)

    Hountondji, Fabien Charles Cossi; Hanna, Rachid; Cherry, Andy J; Sabelis, Maurice W; Agboton, Bonaventure; Korie, Sam

    2007-01-01

    Virulence of entomopathogens is often measured at the individual level using a single host individual or a group of host individuals. To what extent these virulence assessments reflect the impact of an entomopathogen on their host in the field remains largely untested, however. A methodology was developed to induce epizootics of the cassava green mite fungal pathogen Neozygites tanajoae under controlled conditions to evaluate population-level virulence of two (one Beninese and one Brazilian) isolates of the entomopathogen--which had shown similar individual-level virulence but different field impacts. In unrepeated separate experiments we inoculated mite-infested potted cassava plants with either 50 or 25 live mites (high and low inoculum) previously exposed to spores of N. tanajoae and monitored the development of fungal infections for each isolate under the same conditions. Both isolates caused mite infections and an associated decline in host mite populations relative to the control (without fungus) in all experiments, but prevalence of the fungus varied with isolate and increased with inoculum density. Peak infection levels were 90% for the Beninese isolate and 36% for the Brazilian isolate at high inoculum density, and respectively 17% and 25% at low inoculum density. We also measured dispersal from inoculated plants and found that spore dispersal increased with host infection levels, independent of host densities, whereas mite dispersal varied between isolates. These results demonstrate that epizootiology of N. tanajoae can be studied under controlled conditions and suggest that virulence tests at the population level may help to better predict performance of fungal isolates than individual-level tests.

  11. Crystal structures of the fungal pathogen Aspergillus fumigatus protein farnesyltransferase complexed with substrates and inhibitors reveal features for antifungal drug design.

    Science.gov (United States)

    Mabanglo, Mark F; Hast, Michael A; Lubock, Nathan B; Hellinga, Homme W; Beese, Lorena S

    2014-03-01

    Species of the fungal genus Aspergillus are significant human and agricultural pathogens that are often refractory to existing antifungal treatments. Protein farnesyltransferase (FTase), a critical enzyme in eukaryotes, is an attractive potential target for antifungal drug discovery. We report high-resolution structures of A. fumigatus FTase (AfFTase) in complex with substrates and inhibitors. Comparison of structures with farnesyldiphosphate (FPP) bound in the absence or presence of peptide substrate, corresponding to successive steps in ordered substrate binding, revealed that the second substrate-binding step is accompanied by motions of a loop in the catalytic site. Re-examination of other FTase structures showed that this motion is conserved. The substrate- and product-binding clefts in the AfFTase active site are wider than in human FTase (hFTase). Widening is a consequence of small shifts in the α-helices that comprise the majority of the FTase structure, which in turn arise from sequence variation in the hydrophobic core of the protein. These structural effects are key features that distinguish fungal FTases from hFTase. Their variation results in differences in steady-state enzyme kinetics and inhibitor interactions and presents opportunities for developing selective anti-fungal drugs by exploiting size differences in the active sites. We illustrate the latter by comparing the interaction of ED5 and Tipifarnib with hFTase and AfFTase. In AfFTase, the wider groove enables ED5 to bind in the presence of FPP, whereas in hFTase it binds only in the absence of substrate. Tipifarnib binds similarly to both enzymes but makes less extensive contacts in AfFTase with consequently weaker binding.

  12. Global Analysis of the Fungal Microbiome in Cystic Fibrosis Patients Reveals Loss of Function of the Transcriptional Repressor Nrg1 as a Mechanism of Pathogen Adaptation.

    Directory of Open Access Journals (Sweden)

    Sang Hu Kim

    2015-11-01

    different patients, providing a poignant example of parallel evolution. Together, this combined clinical-genomic approach provides a high-resolution portrait of the fungal microbiome of cystic fibrosis patient lungs and identifies a genetic basis of pathogen adaptation.

  13. Antimicrobial mechanism of copper (II 1,10-phenanthroline and 2,2′-bipyridyl complex on bacterial and fungal pathogens

    Directory of Open Access Journals (Sweden)

    S. Chandraleka

    2014-12-01

    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.

  14. Host-pathogen interactions. XV. Fungal glucans which elicit phytoalexin accumulation in soybean also elicit the accumulation of phytoalexins in other plants

    Energy Technology Data Exchange (ETDEWEB)

    Cline, K.; Wade, M.; Albersheim, P.

    1978-01-01

    A ..beta..-glucan isolated from the mycelial walls of Phytophthora megasperma var. sojae and a glucan purified from yeast extract stimulate the accumulation of phytoalexins in red kidney bean, Phaseolus vulgaris, and stimulate the accumulation of the phytoalexin, rishitin, in potato tubers, Solanum tuberosum. Treatment of kidney bean cotyledons with the glucan elicitors resulted in the accumulation of at least five fungistatic compounds. These compounds migrate during thin layer chromatography identically to the fungistatic compounds which accumulate in kidney beans which have been inoculated with Colletotrichum lindemuthianum, a fungal pathogen of kidney beans. Potatoes accumulate as much as 29 micrograms of rishitin per gram fresh weight following exposure to the glucan from Phytophthora megasperma va. sojae and as much as 19.5 micrograms of rishitin per gram fresh weight following exposure to yeast glucan.

  15. Finished genome of the fungal wheat pathogen Mycosphaerella graminicola reveals dispensome structure, chromosome plasticity, and stealth pathogenesis.

    Directory of Open Access Journals (Sweden)

    Stephen B Goodwin

    2011-06-01

    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

  16. Fungal flora and aflatoxin contamination in Pakistani wheat kernels (Triticum aestivum L. and their attribution in seed germination

    Directory of Open Access Journals (Sweden)

    Muhammad Asif Asghar

    2016-07-01

    Full Text Available This study aimed to isolate fungal pathogens and to subsequently quantify aflatoxin (AF; B1 + B2 + G1 + G2 contamination in wheat crops grown in Pakistan. Accordingly, a total of 185 wheat samples were collected from different areas of Pakistan and numerous potent fungal pathogens were isolated. AF contamination attributed to the presence of intoxicating fungal pathogens and resulting metabolic activities were quantified using a high performance liquid chromatography-fluorescence detector coupled with postcolumn derivatization. Additionally, the effect of fungal pathogens on seed germination was also examined. The results obtained showed that 50% of tested wheat samples were found to be contaminated with a diverse range of fungal species. The rate of recurrence of fungal pathogens were Aspergillus 31%, Penicillium 9%, Fusarium 8%, Rhizopus 3%, and Alternaria 2%. The presence of Tilletia indica and Claviceps purpurea species was found to be inevident in all tested wheat samples. AFB1 contamination was detected in 48 (26.0% samples and AFB2 in 13 (7.0% samples. AFG1 and AFG2 were not found in any of the tested samples. The contamination range of AFB1 and AFB2 was 0.05–4.78 μg/kg and 0.02–0.48 μg/kg, respectively. The total amount of AFs (B1 + B2 found in 48 (26.0% samples had a mean level of 0.53 ± 0.40 μg/kg and a contamination range of 0.02–5.26 μg/kg. The overall results showed that in 137 (74.0% samples, AFs were not found within detectable limits. Furthermore, in 180 (97.2% samples, AF levels were found to be below the maximum tolerated levels (MTL recommended by the European Union (4 μg/kg. In five (2.7% samples, AF contamination was higher than the MTL of the European Union. However, these samples were fit for human consumption with reference to the MTL (20 μg/kg assigned by the USA (Food and Drug Administration and Food and Agriculture Organization and Pakistan (Pakistan Standards and Quality Control Authority

  17. 甲真菌病400例致病真菌分析%Analysis of pathogenic fungal strains in 400 patients of onychomycosis

    Institute of Scientific and Technical Information of China (English)

    马越娥; 李秀丽; 顾俊瑛; 刘至昱; 高飞; 王茠茠

    2014-01-01

    目的:确定上海地区甲真菌病的致病菌种。方法:对本院皮肤科门诊就诊的直接镜检阳性的400例甲真菌病患者的甲标本做真菌分离培养和分析。结果:分离出致病真菌233株,其中皮肤癣菌120株(红色毛癣菌104株,须癣毛癣菌10株,犬小孢子菌3株,絮状表皮癣菌3株),酵母菌68株,非皮肤癣菌11株(曲霉6株,青霉5株),其余为丝状真菌。结论:上海地区甲真菌病的致病真菌以皮肤癣菌为主,酵母菌中非白念珠菌占有一定比例。%Objective:To determine the pathogenic fungal strains isolated from onychomycosis in Shanghai. Methods:Fungal culture was performed on 400 patients of onychomycosis with positive results by direct mi-croscopic examination. Results:A total of 233 strains of fungi was isolated,of which 120 strains were derma-tophytes ( Trichophyton rubrum in 104 isolates, Trichophyton mentagrophytes in 10, Microsporum canis in 3 and Epidermophyton floccosum in 3), 68 were Saccharomycetes, 11 were non-dermatophytes ( Aspergillus 6 and Mould 5) and the rest were filamentous fungi. Conclusion:In Shanghai,the dominated pathogenic fungus of onychomycosis is Trichophyton rubrum, and the non-Candida albicans accounts for a proportion of the yeast.

  18. Ecological genetic divergence of the fungal pathogen Didymella rabiei on sympatric wild and domesticated Cicer spp. (Chickpea).

    Science.gov (United States)

    Frenkel, Omer; Peever, Tobin L; Chilvers, Martin I; Ozkilinc, Hilal; Can, Canan; Abbo, Shahal; Shtienberg, Dani; Sherman, Amir

    2010-01-01

    For millennia, chickpea (Cicer arietinum) has been grown in the Levant sympatrically with wild Cicer species. Chickpea is traditionally spring-sown, while its wild relatives germinate in the autumn and develop in the winter. It has been hypothesized that the human-directed shift of domesticated chickpea to summer production was an attempt to escape the devastating Ascochyta disease caused by Didymella rabiei. We estimated genetic divergence between D. rabiei isolates sampled from wild Cicer judaicum and domesticated C. arietinum and the potential role of temperature adaptation in this divergence. Neutral genetic markers showed strong differentiation between pathogen samples from the two hosts. Isolates from domesticated chickpea demonstrated increased adaptation to higher temperatures when grown in vitro compared with isolates from the wild host. The distribution of temperature responses among progeny from crosses of isolates from C. judaicum with isolates from C. arietinum was continuous, suggesting polygenic control of this trait. In vivo inoculations of host plants indicated that pathogenic fitness of the native isolates was higher than that of their hybrid progeny. The results indicate that there is a potential for adaptation to higher temperatures; however, the chances for formation of hybrids which are capable of parasitizing both hosts over a broad temperature range are low. We hypothesize that this pathogenic fitness cost is due to breakdown of coadapted gene complexes controlling pathogenic fitness on each host and may be responsible for maintenance of genetic differentiation between the pathogen demes.

  19. Fungal Sinusitis

    Science.gov (United States)

    ... Marketplace Find an ENT Doctor Near You Fungal Sinusitis Fungal Sinusitis Patient Health Information News media interested ... sinusitis results. There Are Four Types Of Fungal Sinusitis: Mycetoma Fungal Sinusitis produces clumps of spores, a " ...

  20. Identification of an ancestral resistance gene cluster involved in the coevolution process between Phaseolus vulgaris and its fungal pathogen Colletotrichum lindemuthianum.

    Science.gov (United States)

    Geffroy, V; Sicard, D; de Oliveira, J C; Sévignac, M; Cohen, S; Gepts, P; Neema, C; Langin, T; Dron, M

    1999-09-01

    The recent cloning of plant resistance (R) genes and the sequencing of resistance gene clusters have shed light on the molecular evolution of R genes. However, up to now, no attempt has been made to correlate this molecular evolution with the host-pathogen coevolution process at the population level. Cross-inoculations were carried out between 26 strains of the fungal pathogen Colletotrichum lindemuthianum and 48 Phaseolus vulgaris plants collected in the three centers of diversity of the host species. A high level of diversity for resistance against the pathogen was revealed. Most of the resistance specificities were overcome in sympatric situations, indicating an adaptation of the pathogen to the local host. In contrast, plants were generally resistant to allopatric strains, suggesting that R genes that were efficient against exotic strains but had been overcome locally were maintained in the plant genome. These results indicated that coevolution processes between the two protagonists led to a differentiation for resistance in the three centers of diversity of the host. To improve our understanding of the molecular evolution of these different specificities, a recombinant inbred (RI) population derived from two representative genotypes of the Andean (JaloEEP558) and Mesoamerican (BAT93) gene pools was used to map anthracnose specificities. A gene cluster comprising both Andean (Co-y; Co-z) and Mesoamerican (Co-9) host resistance specificities was identified, suggesting that this locus existed prior to the separation of the two major gene pools of P. vulgaris. Molecular analysis revealed a high level of complexity at this locus. It harbors 11 restriction fragment length polymorphisms when R gene analog (RGA) clones are used. The relationship between the coevolution process and diversification of resistance specificities at resistance gene clusters is discussed.

  1. Development of a rapid and simple Agrobacterium tumefaciens mediated transformation system for the fungal pathogen Heterobasidion annosum

    Science.gov (United States)

    Nicklas Samils; Malin Elfstrand; Daniel L. Lindner Czederpiltz; Jan Fahleson; Ake Olson; Christina Dixelius; Jan Stenlid

    2006-01-01

    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...

  2. The role of infochemicals in the interaction between cassava green mite and its fungal pathogen Neozygites tanajoae

    NARCIS (Netherlands)

    Hountondji, F.C.C.; Sabelis, M.W.; Hanna, R.; Sabelis, M.W.; Bruin, J.

    2010-01-01

    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

  3. Jasmonate signalling drives time-of-day differences in susceptibility of Arabidopsis to the fungal pathogen Botrytis cinerea

    NARCIS (Netherlands)

    Ingle, R.A.; Stoker, C.; Stone, W.; Adams, N.; Smith, R.W.; Grant, M.; Carré, I.; Roden, L.C.; Denby, K.J.

    2015-01-01

    The circadian clock, an internal timekeeping 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 fu

  4. Studies towards the Intrinsic Function of the AVR4 and AVR9 Elicitors of the Fungal Tomato Pathogen Cladosporium fulvum

    NARCIS (Netherlands)

    Burg, van den H.A.

    2003-01-01

    Recognition of the extracellular race-specific elicitor proteins AVR4 and AVR9 produced by the pathogenic fungus Cladosporium fulvum is mediated by the tomato resistance genes Cf-4 and Cf-9 , respectively. Recognition of these elicitors triggers host defense responses resulting in full resistance

  5. Finished Genome of the Fungal Wheat Pathogen Mycosphaerella graminicola Reveals Dispensome Structure, Chromosome Plasticity, and Stealth Pathogenesis

    NARCIS (Netherlands)

    Goodwin, S.B.; M'Barek, Ben S.; Dhillon, B.; Wittenberg, A.H.J.; Crane, C.F.; Hane, J.K.; Foster, A.J.; Lee, van der T.A.J.; Grimwood, J.; Aerts, A.; Antoniw, J.; Bailey, A.; Bluhm, B.; Bowler, J.; Bristow, J.; Burgt, van der A.; Canto-Canché, B.; Churchill, A.C.L.; Conde-Ferràez, L.; Cools, H.J.; Coutinho, P.M.; Csukai, M.; Dehal, P.; Wit, de P.J.G.M.; Donzelli, B.; Geest, van de H.C.; Ham, van R.C.H.J.; Hammond-Kosack, K.E.; Henrissat, B.; Kilian, A.; Kobayashi, A.K.; Koopmann, E.; Kourmpetis, Y.; Kuzniar, A.; Lindquist, E.; Lombard, V.; Maliepaard, C.A.; Martins, N.; Mehrabi, A.; Nap, J.P.H.; Ponomarenko, A.; Rudd, J.J.; Salamov, A.; Schmutz, J.; Schouten, H.J.; Shapiro, H.; Stergiopoulos, I.; Torriani, S.F.F.; Tu, H.; Vries, de R.P.; Waalwijk, C.; Ware, S.B.; Wiebenga, A.; Zwiers, L.H.; Oliver, R.P.; Grigoriev, I.V.; Kema, G.H.J.

    2011-01-01

    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. C

  6. The role of infochemicals in the interaction between cassava green mite and its fungal pathogen Neozygites tanajoae

    NARCIS (Netherlands)

    F.C.C. Hountondji; M.W. Sabelis; R. Hanna

    2006-01-01

    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 th

  7. Genome and Transcriptome Analysis of the Fungal Pathogen Fusarium oxysporum f. sp. cubense Causing Banana Vascular Wilt Disease

    Science.gov (United States)

    Zeng, Huicai; Fan, Dingding; Zhu, Yabin; Feng, Yue; Wang, Guofen; Peng, Chunfang; Jiang, Xuanting; Zhou, Dajie; Ni, Peixiang; Liang, Changcong; Liu, Lei; Wang, Jun; Mao, Chao

    2014-01-01

    Background The asexual fungus Fusarium oxysporum f. sp. cubense (Foc) causing vascular wilt disease is one of the most devastating pathogens of banana (Musa spp.). To understand the molecular underpinning of pathogenicity in Foc, the genomes and transcriptomes of two Foc isolates were sequenced. Methodology/Principal Findings Genome analysis revealed that the genome structures of race 1 and race 4 isolates were highly syntenic with those of F. oxysporum f. sp. lycopersici strain Fol4287. A large number of putative virulence associated genes were identified in both Foc genomes, including genes putatively involved in root attachment, cell degradation, detoxification of toxin, transport, secondary metabolites biosynthesis and signal transductions. Importantly, relative to the Foc race 1 isolate (Foc1), the Foc race 4 isolate (Foc4) has evolved with some expanded gene families of transporters and transcription factors for transport of toxins and nutrients that may facilitate its ability to adapt to host environments and contribute to pathogenicity to banana. Transcriptome analysis disclosed a significant difference in transcriptional responses between Foc1 and Foc4 at 48 h post inoculation to the banana ‘Brazil’ in comparison with the vegetative growth stage. Of particular note, more virulence-associated genes were up regulated in Foc4 than in Foc1. Several signaling pathways like the mitogen-activated protein kinase Fmk1 mediated invasion growth pathway, the FGA1-mediated G protein signaling pathway and a pathogenicity associated two-component system were activated in Foc4 rather than in Foc1. Together, these differences in gene content and transcription response between Foc1 and Foc4 might account for variation in their virulence during infection of the banana variety ‘Brazil’. Conclusions/Significance Foc genome sequences will facilitate us to identify pathogenicity mechanism involved in the banana vascular wilt disease development. These will thus advance

  8. Genome and transcriptome analysis of the fungal pathogen Fusarium oxysporum f. sp. cubense causing banana vascular wilt disease.

    Directory of Open Access Journals (Sweden)

    Lijia Guo

    Full Text Available BACKGROUND: The asexual fungus Fusarium oxysporum f. sp. cubense (Foc causing vascular wilt disease is one of the most devastating pathogens of banana (Musa spp.. To understand the molecular underpinning of pathogenicity in Foc, the genomes and transcriptomes of two Foc isolates were sequenced. METHODOLOGY/PRINCIPAL FINDINGS: Genome analysis revealed that the genome structures of race 1 and race 4 isolates were highly syntenic with those of F. oxysporum f. sp. lycopersici strain Fol4287. A large number of putative virulence associated genes were identified in both Foc genomes, including genes putatively involved in root attachment, cell degradation, detoxification of toxin, transport, secondary metabolites biosynthesis and signal transductions. Importantly, relative to the Foc race 1 isolate (Foc1, the Foc race 4 isolate (Foc4 has evolved with some expanded gene families of transporters and transcription factors for transport of toxins and nutrients that may facilitate its ability to adapt to host environments and contribute to pathogenicity to banana. Transcriptome analysis disclosed a significant difference in transcriptional responses between Foc1 and Foc4 at 48 h post inoculation to the banana 'Brazil' in comparison with the vegetative growth stage. Of particular note, more virulence-associated genes were up regulated in Foc4 than in Foc1. Several signaling pathways like the mitogen-activated protein kinase Fmk1 mediated invasion growth pathway, the FGA1-mediated G protein signaling pathway and a pathogenicity associated two-component system were activated in Foc4 rather than in Foc1. Together, these differences in gene content and transcription response between Foc1 and Foc4 might account for variation in their virulence during infection of the banana variety 'Brazil'. CONCLUSIONS/SIGNIFICANCE: Foc genome sequences will facilitate us to identify pathogenicity mechanism involved in the banana vascular wilt disease development. These will

  9. Battle through signaling between wheat and the fungal pathogen Septoria tritici revealed by proteomics and phosphoproteomics

    DEFF Research Database (Denmark)

    Yang, Fen; Braga, Marcella Nunes de Melo; Larsen, Martin Røssel

    2013-01-01

    compatible and incompatible interactions. However, differential regulation of the phosphorylation status of signaling proteins, transcription and translation regulators, and membrane-associated proteins was observed between two interactions. The proteomic data were correlated with a more rapid or stronger......-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...... in facilitating the initial symptomless growth. Taken in its entirety, our dataset suggests interplay between the plant and S. tritici through complex signaling networks and downstream molecular events. Resistance is likely related to several rapidly and intensively triggered signal transduction cascades...

  10. Comparison of different protocols for DNA preparation and PCR for the detection of fungal pathogens in vitro.

    Science.gov (United States)

    Lugert, R; Schettler, C; Gross, U

    2006-07-01

    Although a large number of different PCR protocols for the detection of fungal DNA from clinical samples have been described, a generally recognised standardisation has not yet been developed. In a first step, we compared six different methods to isolate DNA under in vitro conditions from Aspergillus fumigatus, Candida albicans and Saccharomyces cerevisiae with respect to efficiency and expenditure of time. To this end, methods were tested that are based on both mechanical and enzymatic/thermic lysis. Thereby, enzymatic/thermic lysis were shown to be superior to mechanical lysis, although these methods of DNA isolation were more time consuming. The subsequent comparison of three different PCR protocols showed real-time PCR to be the most sensitive method.

  11. PCR-based detection and characterization of the fungal pathogens Colletotrichum gloeosporioides and Colletotrichum capsici causing anthracnose in papaya (Carica papaya l.) in the Yucatan peninsula.

    Science.gov (United States)

    Tapia-Tussell, Raul; Quijano-Ramayo, Andres; Cortes-Velazquez, Alberto; Lappe, Patricia; Larque-Saavedra, Alfonso; Perez-Brito, Daisy

    2008-11-01

    Colletotrichum gloeosporioides is the common causal agent of anthracnose in papaya (Carica papaya L.) fruits, and infection by this fungal pathogen results in severe post-harvest losses. In the Yucatán peninsula (Mexico) a different Colletotrichum species was isolated from papaya fruits with atypical anthracnose lesions. The DNAs from a variety of Colletotrichum isolates producing typical and atypical lesions, respectively, were amplified by PCR with C.gloeosporioides-specific primers. All isolates from typical anthracnose lesions yielded a 450 bp PCR product, but DNAs from isolates with atypical lesions failed to produce an amplification product. For further characterization, the rDNA 5.8S-ITS region was amplified by PCR and processed for sequencing and RFLP analysis, respectively, to verify the identity of the papaya anthracnose pathogens. The results revealed unequivocally the existence of two Colletotrichum species causing anthracnose lesions on papaya fruits: C. gloeosporioides and C. capsici. PCR-RFLP using the restriction endonuclease MspI reliably reproduced restriction patterns specific for C. capsici or C. gloeosporioides. The generation of RFLP patterns by MspI (or AluI or RsaI) is a rapid, accurate, and unequivocal method for the detection and differentiation of these two Colletotrichum species.

  12. Tissue-specific and pathogen-inducible expression of a fusion protein containing a Fusarium-specific antibody and a fungal chitinase protects wheat against Fusarium pathogens and mycotoxins.

    Science.gov (United States)

    Cheng, Wei; Li, He-Ping; Zhang, Jing-Bo; Du, Hong-Jie; Wei, Qi-Yong; Huang, Tao; Yang, Peng; Kong, Xian-Wei; Liao, Yu-Cai

    2015-06-01

    Fusarium head blight (FHB) in wheat and other small grain cereals is a globally devastating disease caused by toxigenic Fusarium pathogens. Controlling FHB is a challenge because germplasm that is naturally resistant against these pathogens is inadequate. Current control measures rely on fungicides. Here, an antibody fusion comprised of the Fusarium spp.-specific recombinant antibody gene CWP2 derived from chicken, and the endochitinase gene Ech42 from the biocontrol fungus Trichoderma atroviride was introduced into the elite wheat cultivar Zhengmai9023 by particle bombardment. Expression of this fusion gene was regulated by the lemma/palea-specific promoter Lem2 derived from barley; its expression was confirmed as lemma/palea-specific in transgenic wheat. Single-floret inoculation of independent transgenic wheat lines of the T3 to T6 generations revealed significant resistance (type II) to fungal spreading, and natural infection assays in the field showed significant resistance (type I) to initial infection. Gas chromatography-mass spectrometry analysis revealed marked reduction of mycotoxins in the grains of the transgenic wheat lines. Progenies of crosses between the transgenic lines and the FHB-susceptible cultivar Huamai13 also showed significantly enhanced FHB resistance. Quantitative real-time PCR analysis revealed that the tissue-specific expression of the antibody fusion was induced by salicylic acid drenching and induced to a greater extent by F. graminearum infection. Histochemical analysis showed substantial restriction of mycelial growth in the lemma tissues of the transgenic plants. Thus, the combined tissue-specific and pathogen-inducible expression of this Fusarium-specific antibody fusion can effectively protect wheat against Fusarium pathogens and reduce mycotoxin content in grain. © 2014 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

  13. Overexpression of TaPIEP1, a pathogen-induced ERF gene of wheat, confers host-enhanced resistance to fungal pathogen Bipolaris sorokiniana.

    Science.gov (United States)

    Dong, Na; Liu, Xin; Lu, Yan; Du, Lipu; Xu, Huijun; Liu, Hongxia; Xin, Zhiyong; Zhang, Zengyan

    2010-05-01

    Bipolaris sorokiniana is an economically important phytopathogen of wheat and other cereal species. In this paper, a novel pathogen-induced ethylene-responsive factor (ERF) gene of wheat, TaPIEP1, was isolated and characterized. The transcript of TaPIEP1 was significantly and rapidly induced by treatments with B. sorokiniana, and with ethylene (ET), jasmonate (JA), and abscisic acid. Molecular and biochemical assays demonstrated that TaPIEP1 is a new ERF transcription activator belonging to B-3c subgroup of the ERF family. Transgenic wheat lines overexpressing TaPIEP1 were generated by biolistic bombardment and molecular screening. Compared with the host wheat Yangmai12, six stable transgenic wheat lines overexpressing TaPIEP1 that exhibited significantly increased resistance to B. sorokiniana were identified by molecular detection in the T(0)-T(4) generations and by disease resistance tests. The degree of the enhanced resistance was correlated with an accumulation of the transcript level of TaPIEP1. Furthermore, the transcript levels of certain defense-related genes in the ET/JA pathways were markedly increased in the transgenic wheat plants with enhanced resistance. These results reveal that TaPIEP1 overexpression in wheat could obviously improve resistance to B. sorokiniana via activation of some defense genes, and TaPIEP1 gene may be useful in improving crop resistance to the pathogen.

  14. Fusion of two divergent fungal individuals led to the recent emergence of a unique widespread pathogen species

    Science.gov (United States)

    Stukenbrock, Eva Holtgrewe; Christiansen, Freddy Bugge; Hansen, Troels Toftebjerg; Dutheil, Julien Yann; Schierup, Mikkel Heide

    2012-01-01

    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. PMID:22711811

  15. Inverse pH regulation of plant and fungal sucrose transporters: a mechanism to regulate competition for sucrose at the host/pathogen interface?

    Directory of Open Access Journals (Sweden)

    Kathrin Wippel

    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.

  16. The human fungal pathogen Cryptococcus neoformans escapes macrophages by a phagosome emptying mechanism that is inhibited by Arp2/3 complex-mediated actin polymerisation.

    Directory of Open Access Journals (Sweden)

    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.

  17. Enhancing rice resistance to fungal pathogens by transformation with cell wall degrading enzyme genes from Trichoderma atroviride

    Institute of Scientific and Technical Information of China (English)

    LIU Mei (刘梅); SUN Zong-xiu (孙宗修); ZHU Jie (朱洁); XU Tong (徐同); HARMAN Gary E.; LORITO Matteo

    2004-01-01

    Three genes encoding for fungal cell wall degrading enzymes (CWDEs), ech42, nag70 and gluc78 from the biocontrol fungus Trichoderma atroviride were inserted into the binary vector pCAMBIA1305.2 singly and in all possible combinations and transformed to rice plants. More than 1800 independently regenerated plantlets in seven different populations (for each of the three genes and each of the four gene combinations) were obtained. The ech42 gene encoding for an endochitinase increased resistance to sheath blight caused by Rhizoctonia solani, while the exochitinase-encoding gene, nag70, had lesser effect. The expression level of endochitinase but exochitinase was correlated with disease resistance. Nevertheless, exochitinase enhanced the effect of endochitinase on disease resistance when the two genes co-expressed in transgenics. Resistance to Magnaporthe grisea was found in all kinds of regenerated plants including that with single gluc78. A few lines expressing either ech42 or nag70 gene were immune to the disease. Transgenic plants are being tested to further evaluate disease resistance at field level. This is the first report of multiple of expression of genes encoding CWDEs from Trichoderma atroviride that result in resistance to blast and sheath blight in rice.

  18. Rice transformation with cell wall degrading enzyme genes from Trichoderma atroviride and its effect on plant growth and resistance to fungal pathogens

    Institute of Scientific and Technical Information of China (English)

    Liu Mei; Sun Zong-Xiu; Zhu Jie; Xu Tong; Gary E Harman; Matteo Lorito; Sheri Woo

    2004-01-01

    @@ Three genes encoding for fungal cell wall degrading enzymes (CWDE), ech42, nag70 and gluc78from the biocontrol fungus Trichoderma atroviride were inserted into the binary vector pCAMBIA1305. 2 singly and in all possible combinations. The coding sequences were placed downstream of the rice actin promoter and all vectors were used to transform rice plants. A total of more than 1,800 independently regenerated plantlets in seven different populations (for each of the three genes and each of the four gene combinations) were obtained. Expression in plant was obtained for all the fungal genes used singly or in combinations. The ech42 gene encoding for an endochitinase increased resistance to sheath blight caused by Rhizoctonia solani, while the exochitinase-encoding gene, nag70, had a lesser effect. The expression level of endochitinase but not of the exochitinase was correlated with disease resistance. Nevertheless, exochitinase enhanced the positive effect of endochitinase on disease resistance when two genes were co-expressed in transgenic rice. Improved resistance to Magnaporthe grisea was found in all types of regenerated plants, including those with the gluc78 gene alone, while a few lines expressing either ech42 or nag70 appeared to be immune to this pathogen. Transgenic plants expressing the gluc78 gene alone were stunted and only few of them survived, even though they showed resistance to M. grisea. However, combination with either one of the two other genes ( ech42, nag70 ) as included in the same T-DNA region, reduced the negative effect of gluc78 on plant growth. This is the first report of single or multiple of expression of transgens encoding CWDEs that results in resistance to blast and sheath blight in rice.

  19. Filamentous fungal-specific septin AspE is phosphorylated in vivo and interacts with actin, tubulin and other septins in the human pathogen Aspergillus fumigatus

    Energy Technology Data Exchange (ETDEWEB)

    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: bill.steinbach@duke.edu [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)

    2013-02-15

    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.

  20. DNA Extraction Method Affects the Detection of a Fungal Pathogen in Formalin-Fixed Specimens Using qPCR.

    Science.gov (United States)

    Adams, Andrea J; LaBonte, John P; Ball, Morgan L; Richards-Hrdlicka, Kathryn L; Toothman, Mary H; Briggs, Cheryl J

    2015-01-01

    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

  1. A soluble fucose-specific lectin from Aspergillus fumigatus conidia--structure, specificity and possible role in fungal pathogenicity.

    Science.gov (United States)

    Houser, Josef; Komarek, Jan; Kostlanova, Nikola; Cioci, Gianluca; Varrot, Annabelle; Kerr, Sheena C; Lahmann, Martina; Balloy, Viviane; Fahy, John V; Chignard, Michel; Imberty, Anne; Wimmerova, Michaela

    2013-01-01

    Aspergillus fumigatus is an important allergen and opportunistic pathogen. Similarly to many other pathogens, it is able to produce lectins that may be involved in the host-pathogen interaction. We focused on the lectin AFL, which was prepared in recombinant form and characterized. Its binding properties were studied using hemagglutination and glycan array analysis. We determined the specificity of the lectin towards l-fucose and fucosylated oligosaccharides, including α1-6 linked core-fucose, which is an important marker for cancerogenesis. Other biologically relevant saccharides such as sialic acid, d-mannose or d-galactose were not bound. Blood group epitopes of the ABH and Lewis systems were recognized, Le(Y) being the preferred ligand among others. To provide a correlation between the observed functional characteristics and structural basis, AFL was crystallized in a complex with methyl-α,L-selenofucoside and its structure was solved using the SAD method. Six binding sites, each with different compositions, were identified per monomer and significant differences from the homologous AAL lectin were found. Structure-derived peptides were utilized to prepare anti-AFL polyclonal antibodies, which suggested the presence of AFL on the Aspergillus' conidia, confirming its expression in vivo. Stimulation of human bronchial cells by AFL led to IL-8 production in a dose-dependent manner. AFL thus probably contributes to the inflammatory response observed upon the exposure of a patient to A. fumigatus. The combination of affinity to human epithelial epitopes, production by conidia and pro-inflammatory activity is remarkable and shows that AFL might be an important virulence factor involved in an early stage of A. fumigatus infection.

  2. DNA Extraction Method Affects the Detection of a Fungal Pathogen in Formalin-Fixed Specimens Using qPCR.

    Directory of Open Access Journals (Sweden)

    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

  3. Characterization of a JAZ7 activation-tagged Arabidopsis mutant with increased susceptibility to the fungal pathogen Fusarium oxysporum

    Science.gov (United States)

    Thatcher, Louise F.; Cevik, Volkan; Grant, Murray; Zhai, Bing; Jones, Jonathan D.G.; Manners, John M.; Kazan, Kemal

    2016-01-01

    In Arabidopsis, jasmonate (JA)-signaling plays a key role in mediating Fusarium oxysporum disease outcome. However, the roles of JASMONATE ZIM-domain (JAZ) proteins that repress JA-signaling have not been characterized in host resistance or susceptibility to this pathogen. Here, we found most JAZ genes are induced following F. oxysporum challenge, and screening T-DNA insertion lines in Arabidopsis JAZ family members identified a highly disease-susceptible JAZ7 mutant (jaz7-1D). This mutant exhibited constitutive JAZ7 expression and conferred increased JA-sensitivity, suggesting activation of JA-signaling. Unlike jaz7 loss-of-function alleles, jaz7-1D also had enhanced JA-responsive gene expression, altered development and increased susceptibility to the bacterial pathogen Pst DC3000 that also disrupts host JA-responses. We also demonstrate that JAZ7 interacts with transcription factors functioning as activators (MYC3, MYC4) or repressors (JAM1) of JA-signaling and contains a functional EAR repressor motif mediating transcriptional repression via the co-repressor TOPLESS (TPL). We propose through direct TPL recruitment, in wild-type plants JAZ7 functions as a repressor within the JA-response network and that in jaz7-1D plants, misregulated ectopic JAZ7 expression hyper-activates JA-signaling in part by disturbing finely-tuned COI1-JAZ-TPL-TF complexes. PMID:26896849

  4. Characterization of a JAZ7 activation-tagged Arabidopsis mutant with increased susceptibility to the fungal pathogen Fusarium oxysporum.

    Science.gov (United States)

    Thatcher, Louise F; Cevik, Volkan; Grant, Murray; Zhai, Bing; Jones, Jonathan D G; Manners, John M; Kazan, Kemal

    2016-04-01

    In Arabidopsis, jasmonate (JA)-signaling plays a key role in mediating Fusarium oxysporum disease outcome. However, the roles of JASMONATE ZIM-domain (JAZ) proteins that repress JA-signaling have not been characterized in host resistance or susceptibility to this pathogen. Here, we found most JAZ genes are induced following F. oxysporum challenge, and screening T-DNA insertion lines in Arabidopsis JAZ family members identified a highly disease-susceptible JAZ7 mutant (jaz7-1D). This mutant exhibited constitutive JAZ7 expression and conferred increased JA-sensitivity, suggesting activation of JA-signaling. Unlike jaz7 loss-of-function alleles, jaz7-1D also had enhanced JA-responsive gene expression, altered development and increased susceptibility to the bacterial pathogen PstDC3000 that also disrupts host JA-responses. We also demonstrate that JAZ7 interacts with transcription factors functioning as activators (MYC3, MYC4) or repressors (JAM1) of JA-signaling and contains a functional EAR repressor motif mediating transcriptional repression via the co-repressor TOPLESS (TPL). We propose through direct TPL recruitment, in wild-type plants JAZ7 functions as a repressor within the JA-response network and that in jaz7-1D plants, misregulated ectopic JAZ7 expression hyper-activates JA-signaling in part by disturbing finely-tuned COI1-JAZ-TPL-TF complexes.

  5. Allozyme-specific modification of a maize seed chitinase by a protein secreted by the fungal pathogen Stenocarpella maydis.

    Science.gov (United States)

    Naumann, Todd A; Wicklow, Donald T

    2010-07-01

    Stenocarpella maydis causes both dry-ear rot and stalk rot of maize. Maize inbred lines have varying levels of resistance to ear rot caused by S. maydis. The genetic basis of resistance appears to rely on multiple genetic factors, none of which are known. The commonly used stiff-stalk inbred line B73 has been shown to be strongly susceptible to ear rot caused by S. maydis. Here, we report that the ChitA protein alloform from B73, ChitA-F, encoded by a known allele of the chiA gene, is susceptible to modification by a protein (Stm-cmp) secreted by S. maydis. We also identify a new allele of chiA (from inbred line LH82) which encodes ChitA-S, an alloform of ChitA that is resistant to Stm-cmp modification. Chitinase zymogram analysis of seed from a commercial field showed the presence of both ChitA alloforms in healthy ears, and showed that ChitA-F but not ChitA-S was modified in ears rotted by S. maydis. The ChitA-F protein was purified from inbred line B73 and ChitA-S from LH82. ChitA-F was modified more efficiently than ChitA-S by S. maydis protein extracts in vitro. The chiA gene from LH82 was cloned and sequenced. It is a novel allele that encodes six polymorphisms relative to the known allele from B73. This is the first demonstration that the susceptibility to modification of a fungal targeted plant chitinase differs among inbred lines. These findings suggest that the LH82 chiA allele may be a specific genetic determinant that contributes to resistance to ear rot caused by S. maydis whereas the B73 allele may contribute to susceptibility.

  6. What was old is new again: thermal adaptation within clonal lineages during range expansion in a fungal pathogen.

    Science.gov (United States)

    Robin, Cécile; Andanson, Audrey; Saint-Jean, Gilles; Fabreguettes, Olivier; Dutech, Cyril

    2017-01-31

    Range-expanding species are expected to gain an increasing importance in the context of global change. They provide a great opportunity to study contemporary evolutionary changes and to unravel the mechanisms of evolution. Cryphonectria parasitica, the causal agent of chestnut blight, originating from Asia, has been spread since the beginning of the 20th century into different continents. We took advantage of the C. parasitica recent emergence in northern France to study the changes in population genetic structure and in phenotypic traits along this colonization and climatic gradient. Four hundred twenty-seven C. parasitica isolates were sampled in 47 chestnut sites in northern France. The C. parasitica outbreak in the north was found to be due to the expansion of five dominant clonal groups from southern France and to the emergence of a few rare recombined genotypes. The evolutionary changes during C. parasitica range expansion were studied by analyzing phenotypic changes in isolates from the same clonal lineage, with or without a geographic shift. Growth rates were assessed in vitro, at four temperatures. The northern isolates grew faster at 12 and 15°C and more slowly at 28 and 32°C than the southern isolates. These results strongly suggest local adaptation to low temperatures in C. parasitica, with a trade-off of slower growth at high temperatures. They also reflect the high evolutionary potential of C. parasitica along a colonization gradient and show that clonal evolution is not a limitation for the rapid thermal adaptation of this invasive fungal species. This article is protected by copyright. All rights reserved.

  7. Rapidly Evolving Genes Are Key Players in Host Specialization and Virulence of the Fungal Wheat Pathogen Zymoseptoria tritici (Mycosphaerella graminicola.

    Directory of Open Access Journals (Sweden)

    Stephan Poppe

    2015-07-01

    Full Text Available The speciation of pathogens can be driven by divergent host specialization. Specialization to a new host is possible via the acquisition of advantageous mutations fixed by positive selection. Comparative genome analyses of closely related species allows for the identification of such key substitutions via inference of genome-wide signatures of positive selection. We previously used a comparative genomics framework to identify genes that have evolved under positive selection during speciation of the prominent wheat pathogen Zymoseptoria tritici (synonym Mycosphaerella graminicola. In this study, we conducted functional analyses of four genes exhibiting strong signatures of positive selection in Z. tritici. We deleted the four genes in Z. tritici and confirm a virulence-related role of three of the four genes ΔZt80707, ΔZt89160 and ΔZt103264. The two mutants ΔZt80707 and ΔZt103264 show a significant reduction in virulence during infection of wheat; the ΔZt89160 mutant causes a hypervirulent phenotype in wheat. Mutant phenotypes of ΔZt80707, ΔZt89160 and ΔZt103264 can be restored by insertion of the wild-type genes. However, the insertion of the Zt80707 and Zt89160 orthologs from Z. pseudotritici and Z. ardabiliae do not restore wild-type levels of virulence, suggesting that positively selected substitutions in Z. tritici may relate to divergent host specialization. Interestingly, the gene Zt80707 encodes also a secretion signal that targets the protein for cell secretion. This secretion signal is however only transcribed in Z. tritici, suggesting that Z. tritici-specific substitutions relate to a new function of the protein in the extracellular space of the wheat-Z. tritici interaction. Together, the results presented here highlight that Zt80707, Zt103264 and Zt89160 represent key genes involved in virulence and host-specific disease development of Z. tritici. Our findings illustrate that evolutionary predictions provide a powerful tool

  8. Rapidly Evolving Genes Are Key Players in Host Specialization and Virulence of the Fungal Wheat Pathogen Zymoseptoria tritici (Mycosphaerella graminicola)

    Science.gov (United States)

    Poppe, Stephan; Dorsheimer, Lena; Happel, Petra; Stukenbrock, Eva Holtgrewe

    2015-01-01

    The speciation of pathogens can be driven by divergent host specialization. Specialization to a new host is possible via the acquisition of advantageous mutations fixed by positive selection. Comparative genome analyses of closely related species allows for the identification of such key substitutions via inference of genome-wide signatures of positive selection. We previously used a comparative genomics framework to identify genes that have evolved under positive selection during speciation of the prominent wheat pathogen Zymoseptoria tritici (synonym Mycosphaerella graminicola). In this study, we conducted functional analyses of four genes exhibiting strong signatures of positive selection in Z. tritici. We deleted the four genes in Z. tritici and confirm a virulence-related role of three of the four genes ΔZt80707, ΔZt89160 and ΔZt103264. The two mutants ΔZt80707 and ΔZt103264 show a significant reduction in virulence during infection of wheat; the ΔZt89160 mutant causes a hypervirulent phenotype in wheat. Mutant phenotypes of ΔZt80707, ΔZt89160 and ΔZt103264 can be restored by insertion of the wild-type genes. However, the insertion of the Zt80707 and Zt89160 orthologs from Z. pseudotritici and Z. ardabiliae do not restore wild-type levels of virulence, suggesting that positively selected substitutions in Z. tritici may relate to divergent host specialization. Interestingly, the gene Zt80707 encodes also a secretion signal that targets the protein for cell secretion. This secretion signal is however only transcribed in Z. tritici, suggesting that Z. tritici-specific substitutions relate to a new function of the protein in the extracellular space of the wheat-Z. tritici interaction. Together, the results presented here highlight that Zt80707, Zt103264 and Zt89160 represent key genes involved in virulence and host-specific disease development of Z. tritici. Our findings illustrate that evolutionary predictions provide a powerful tool for the

  9. Projecting the Global Distribution of the Emerging Amphibian Fungal Pathogen, Batrachochytrium dendrobatidis, Based on IPCC Climate Futures

    Science.gov (United States)

    Olson, Deanna H.; Blaustein, Andrew R.

    2016-01-01

    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, especially for

  10. Preliminary in vitro insights into the use of natural fungal pathogens of leaf-cutting ants as biocontrol agents.

    Science.gov (United States)

    Folgarait, Patricia; Gorosito, Norma; Poulsen, Michael; Currie, Cameron R

    2011-09-01

    Leaf-cutting ants are one of the main herbivores of the Neotropics, where they represent an important agricultural pest. These ants are particularly difficult to control because of the complex network of microbial symbionts. Leaf-cutting ants have traditionally been controlled through pesticide application, but there is a need for alternative, more environmentally friendly, control methods such as biological control. Potential promising biocontrol candidates include the microfungi Escovopsis spp. (anamorphic Hypocreales), which are specialized pathogens of the fungi the ants cultivate for food. These pathogens are suppressed through ant behaviors and ant-associated antibiotic-producing Actinobacteria. In order to be an effective biocontrol agent, Escovopsis has to overcome these defenses. Here, we evaluate, using microbial in vitro assays, whether defenses in the ant-cultivated fungus strain (Leucoagaricus sp.) and Actinobacteria from the ant pest Acromyrmex lundii have the potential to limit the use of Escovopsis in biocontrol. We also explore, for the first time, possible synergistic biocontrol between Escovopsis and the entomopathogenic fungus Lecanicillium lecanii. All strains of Escovopsis proved to overgrow A. lundii cultivar in less than 7 days, with the Escovopsis strain isolated from a different leaf-cutting ant species being the most efficient. Escovopsis challenged with a Streptomyces strain isolated from A. lundii did not exhibit significant growth inhibition. Both results are encouraging for the use of Escovopsis as a biocontrol agent. Although we found that L. lecanii can suppress the growth of the cultivar, it also had a negative impact on Escovopsis, making the success of simultaneous use of these two fungi for biocontrol of A. lundii questionable.

  11. Projecting the Global Distribution of the Emerging Amphibian Fungal Pathogen, Batrachochytrium dendrobatidis, Based on IPCC Climate Futures.

    Science.gov (United States)

    Xie, Gisselle Yang; Olson, Deanna H; Blaustein, Andrew R

    2016-01-01

    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, especially for

  12. The Genomes of the Fungal Plant Pathogens Cladosporium fulvum and Dothistroma septosporum Reveal Adaptation to Different Hosts and Lifestyles But Also Signatures of Common Ancestry

    Energy Technology Data Exchange (ETDEWEB)

    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.

    2012-05-04

    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.

  13. The genomes of the fungal plant pathogens Cladosporium fulvum and Dothistroma septosporum reveal adaptation to different hosts and lifestyles but also signatures of common ancestry.

    Science.gov (United States)

    de Wit, Pierre J G M; van der Burgt, Ate; Ökmen, Bilal; Stergiopoulos, Ioannis; Abd-Elsalam, Kamel A; Aerts, Andrea L; Bahkali, Ali H; Beenen, Henriek G; Chettri, Pranav; Cox, Murray P; Datema, Erwin; de Vries, Ronald P; Dhillon, Braham; Ganley, Austen R; Griffiths, Scott A; Guo, Yanan; Hamelin, 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 Ham, Roeland C H J; Zhang, Shuguang; Goodwin, Stephen B; Grigoriev, Igor V; Collemare, Jérôme; Bradshaw, Rosie E

    2012-01-01

    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.

  14. Singlet molecular oxygen generation by light-activated DHN-melanin of the fungal pathogen Mycosphaerella fijiensis in black Sigatoka disease of bananas.

    Science.gov (United States)

    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

    2014-01-01

    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.

  15. Singlet molecular oxygen generation by light-activated DHN-melanin of the fungal pathogen Mycosphaerella fijiensis in black Sigatoka disease of bananas.

    Directory of Open Access Journals (Sweden)

    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.

  16. High-Resolution Transcript Profiling of the Atypical Biotrophic Interaction between Theobroma cacao and the Fungal Pathogen Moniliophthora perniciosa[C][W][OPEN

    Science.gov (United States)

    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

    2014-01-01

    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

  17. Multilocus ISSR markers reveal two major genetic groups in Spanish and South African populations of the grapevine fungal pathogen Cadophora luteo-olivacea.

    Directory of Open Access Journals (Sweden)

    David Gramaje

    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.

  18. Host-Pathogen Interactions: XV. Fungal Glucans Which Elicit Phytoalexin Accumulation in Soybean Also Elicit the Accumulation of Phytoalexins in Other Plants.

    Science.gov (United States)

    Cline, K; Wade, M; Albersheim, P

    1978-12-01

    A beta-glucan isolated from the mycelial walls of Phytophthora megasperma var. sojae and a glucan purified from yeast extract stimulate the accumulation of phytoalexins in red kidney bean, Phaseolus vulgaris, and stimulate the accumulation of the phytoalexin, rishitin, in potato tubers, Solanum tuberosum. These glucans have previously been shown to be potent elicitors of glyceollin accumulation in soybean, Glycine max.Treatment of kidney bean cotyledons with the glucan elicitors resulted in the accumulation of at least five fungistatic compounds. These compounds migrate during thin layer chromatography identically to the fungistatic compounds which accumulate in kidney beans which have been inoculated with Colletotrichum lindemuthianum, a fungal pathogen of kidney beans.Potatoes accumulate as much as 29 micrograms of rishitin per gram fresh weight following exposure to the glucan from Phytophthora megasperma var. sojae and as much as 19.5 micrograms of rishitin per gram fresh weight following exposure to yeast glucan. Potatoes accumulated 28 micrograms of rishitin per gram fresh weight following inoculation with live Phytophthora megasperma var. sojae.

  19. The MAP kinase-activated protein kinase Rck2p regulates cellular responses to cell wall stresses, filamentation and virulence in the human fungal pathogen Candida albicans.

    Science.gov (United States)

    Li, Xichuan; Du, Wei; Zhao, Jingwen; Zhang, Lilin; Zhu, Zhiyan; Jiang, Linghuo

    2010-06-01

    Rck2p is the Hog1p-MAP kinase-activated protein kinase required for the attenuation of protein synthesis in response to an osmotic challenge in Saccharomyces cerevisiae. Rck2p also regulates rapamycin sensitivity in both S. cerevisiae and Candida albicans. In this study, we demonstrate that the deletion of CaRCK2 renders C. albicans cells sensitive to, and CaRck2p translocates from the cytosol to the nucleus in response to, cell wall stresses caused by Congo red, Calcoflor White, elevated heat and zymolyase. However, the kinase activity of CaRck2p is not required for the cellular response to these cell wall stresses. Furthermore, transcripts of cell wall protein-encoding genes CaBGL2, CaHWP1 and CaXOG1 are reduced in C. albicans cells lacking CaRCK2. The deletion of CaRCK2 also reduces the in vitro filamentation of C. albicans and its virulence in a mouse model of systemic candidasis. The kinase activity of CaRck2p is required for the virulence, but not for the in vitro filamentation, in C. albicans. Therefore, Rck2p regulates cellular responses to cell wall stresses, filamentation and virulence in the human fungal pathogen C. albicans.

  20. Changes occurring in compositions and antioxidant properties of healthy soybean seeds [Glycine max (L.) Merr.] and soybean seeds diseased by Phomopsis longicolla and Cercospora kikuchii fungal pathogens.

    Science.gov (United States)

    Lee, Jin Hwan; Hwang, Seung-Ryul; Lee, Yeon-Hee; Kim, Kyun; Cho, Kye Man; Lee, Yong Bok

    2015-10-15

    Changes in the compositions (isoflavone, protein, oil, and fatty acid) and antioxidant properties were evaluated in healthy soybeans and soybeans diseased by Phomopsis longicolla and Cercospora kikuchii. The total isoflavone content (1491.3 μg/g) of healthy seeds was observed to be considerably different than that of diseased seeds (P. longicolla: 292.6, C. kikuchii: 727.2 μg/g), with malonlygenistin exhibiting the greatest decrease (726.1 → 57.1, 351.9 μg/g). Significantly, three isoflavones exhibited a slight increase, and their structures were confirmed as daidzein, glycitein, and genistein, based on their molecular ions at m/z 253.1, 283.0, and 269.1 using the negative mode of HPLC-DAD-ESI/MS. The remaining compositions showed slight variations. The effects against 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) radicals in healthy seeds were stronger than the diseased soybeans, depending upon the isoflavone level. Our results may be useful in evaluating the relationship between composition and antioxidant activity as a result of changes caused by soybean fungal pathogens.

  1. Population structure and temporal maintenance of the multihost fungal pathogen Botrytis cinerea: causes and implications for disease management.

    Science.gov (United States)

    Walker, Anne-Sophie; Gladieux, Pierre; Decognet, Véronique; Fermaud, Marc; Confais, Johann; Roudet, Jean; Bardin, Marc; Bout, Alexandre; Nicot, Philippe C; Poncet, Christine; Fournier, Elisabeth

    2015-04-01

    Understanding the causes of population subdivision is of fundamental importance, as studying barriers to gene flow between populations may reveal key aspects of the process of adaptive divergence and, for pathogens, may help forecasting disease emergence and implementing sound management strategies. Here, we investigated population subdivision in the multihost fungus Botrytis cinerea based on comprehensive multiyear sampling on different hosts in three French regions. Analyses revealed a weak association between population structure and geography, but a clear differentiation according to the host plant of origin. This was consistent with adaptation to hosts, but the distribution of inferred genetic clusters and the frequency of admixed individuals indicated a lack of strict host specificity. Differentiation between individuals collected in the greenhouse (on Solanum) and outdoor (on Vitis and Rubus) was stronger than that observed between individuals from the two outdoor hosts, probably reflecting an additional isolating effect associated with the cropping system. Three genetic clusters coexisted on Vitis but did not persist over time. Linkage disequilibrium analysis indicated that outdoor populations were regularly recombining, whereas clonality was predominant in the greenhouse. Our findings open up new perspectives for disease control by managing plant debris in outdoor conditions and reinforcing prophylactic measures indoor.

  2. Impact on Arbuscular Mycorrhiza Formation of Pseudomonas Strains Used as Inoculants for Biocontrol of Soil-Borne Fungal Plant Pathogens

    Science.gov (United States)

    Barea, J. M.; Andrade, G.; Bianciotto, V.; Dowling, D.; Lohrke, S.; Bonfante, P.; O’Gara, F.; Azcon-Aguilar, C.

    1998-01-01

    The arbuscular mycorrhizal symbiosis, a key component of agroecosystems, was assayed as a rhizosphere biosensor for evaluation of the impact of certain antifungal Pseudomonas inoculants used to control soil-borne plant pathogens. The following three Pseudomonas strains were tested: wild-type strain F113, which produces the antifungal compound 2,4-diacetylphloroglucinol (DAPG); strain F113G22, a DAPG-negative mutant of F113; and strain F113(pCU203), a DAPG overproducer. Wild-type strain F113 and mutant strain F113G22 stimulated both mycelial development from Glomus mosseae spores germinating in soil and tomato root colonization. Strain F113(pCU203) did not adversely affect G. mosseae performance. Mycelial development, but not spore germination, is sensitive to 10 μM DAPG, a concentration that might be present in the rhizosphere. The results of scanning electron and confocal microscopy demonstrated that strain F113 and its derivatives adhered to G. mosseae spores independent of the ability to produce DAPG. PMID:9603857

  3. LDS1-produced oxylipins are negative regulators of growth, conidiation and fumonisin synthesis in the fungal maize pathogen Fusarium verticillioides.

    Science.gov (United States)

    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

    2014-01-01

    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.

  4. Allergen Immunotherapy in an HIV+ Patient with Allergic Fungal Rhinosinusitis

    OpenAIRE

    2015-01-01

    Patients with HIV/AIDS can present with multiple types of fungal rhinosinusitis, fungal balls, granulomatous invasive fungal rhinosinusitis, acute or chronic invasive fungal rhinosinusitis, or allergic fungal rhinosinusitis (AFRS). Given the variable spectrum of immune status and susceptibility to severe infection from opportunistic pathogens it is extremely important that clinicians distinguish aggressive fungal invasive fungal disease from the much milder forms such as AFRS. Here we descr...

  5. Screening and modes of action of antagonistic bacteria to control the fungal pathogen Phaeomoniella chlamydospora involved in grapevine trunk diseases.

    Science.gov (United States)

    Haidar, Rana; Roudet, Jean; Bonnard, Olivier; Dufour, Marie Cécile; Corio-Costet, Marie France; Fert, Mathieu; Gautier, Thomas; Deschamps, Alain; Fermaud, Marc

    2016-11-01

    The antagonistic activity of 46 bacterial strains isolated from Bordeaux vineyards were evaluated against Phaeomoniella chlamydospora, a major grapevine pathogen involved in Esca. The reduction of the necrosis length of stem cuttings ranged between 31.4% and 38.7% for the 8 most efficient strains. Two in planta trials allowed the selection of the two best strains, Bacillus pumilus (S32) and Paenibacillus sp. (S19). Their efficacy was not dependent on application method; co-inoculation, prevention in the wood and soil inoculation were tested. The involvement of antibiosis by the secretion of diffusible and/or volatile compounds in the antagonistic capacity of these two strains was assessed in vitro. Volatile compounds secreted by B. pumilus (S32) and Paenibacillus sp. (S19) were identified by gas chromatography/mass spectroscopy (GC/MS). The volatile compounds 1-octen-3-ol and 2,5-dimethyl pyrazine were obtained commercially and tested, and they showed strong antifungal activity against P. chlamydospora, which suggested that these compounds may play an important role in the bacterial antagonistic activity in planta. Furthermore, the expression of 10 major grapevine defense genes was quantified by real-time polymerase chain reaction, which demonstrated that the two strains significantly affected the grapevine transcripts four days after their application on the plants. High expression levels of different genes associated with P. chlamydospora infection in B. pumilus pre-treated plants suggests that this strain induces systemic resistance in grapevine. For the first time, we demonstrated the ability of two bacterial strains, B. pumilus and Paenibacillus sp., isolated from grapevine wood, to control P. chlamydospora via direct and/or indirect mechanisms.

  6. Banana peel culture as an indigenous medium for easy identification of late-sporulation human fungal pathogens

    Directory of Open Access Journals (Sweden)

    A J Kindo

    2016-01-01

    Full Text Available Aim: Fungi are increasing in incidence as human pathogens and newer and rarer species are continuously being encountered. Identifying these species from growth on regular culture media may be challenging due to the absence of typical features. An indigenous and cheap medium, similar to the natural substrate of these fungi, was standardised in our laboratory as an aid to species identification in a conventional laboratory setting. Materials and Methods: Ripe banana peel pieces, sterilised in an autoclave at 121°C temperature and 15 lbs pressure for 15 min promoted good growth of hyphae and pycnidia or acervuli in coelomycetes, flabelliform and medusoid fruiting bodies of basidiomycetes and fruit bodies such as cleistothecium in ascomycetes. The growth from the primary isolation medium was taken and inoculated onto the pieces of double-autoclaved ripe banana peel pieces in a sterile glass Petri dish with some moisture (sprinkles of sterile distilled water. A few sterile coverslips were placed randomly inside the Petri dish for the growing fungus to stick on to it. The plates were kept at room temperature and left undisturbed for 15–20 days. At a time, one coverslip was taken out and placed on a slide with lactophenol cotton blue and focused under the microscope to look for fruit bodies. Results: Lasiodiplodia theobromae, Macrophomina phaseolina, Nigrospora sphaerica, Chaetomium murorum, Nattrassia mangiferae and Schizophyllum commune were identified by characteristic features from growth on banana peel culture. Conclusions: Banana peel culture is a cheap and effective medium resembling the natural substrate of fungi and is useful for promoting characteristic reproductive structures that aid identification.

  7. Common motifs in the response of cereal primary metabolism to fungal pathogens are not based on similar transcriptional reprogramming

    Directory of Open Access Journals (Sweden)

    Lars Matthias Voll

    2011-08-01

    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

  8. TmpL, a transmembrane protein required for intracellular redox homeostasis and virulence in a plant and an animal fungal pathogen.

    Directory of Open Access Journals (Sweden)

    Kwang-Hyung Kim

    2009-11-01

    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.

  9. D-Lysergyl peptide synthetase from the ergot fungus Claviceps purpurea.

    Science.gov (United States)

    Riederer, B; Han, M; Keller, U

    1996-11-01

    The ergot fungus Claviceps purpurea produces the medically important ergopeptines, which consist of a cyclol-structured tripeptide and D-lysergic acid linked by an amide bond. An enzyme activity capable of non-ribosomal synthesis of D-lysergyl-L-alanyl-L-phenylalanyl-L-proline lactam, the non-cyclol precursor of the ergopeptine ergotamine, has been purified about 18-fold from the ergotamine-producing C. purpurea strain D1. Analysis of radioactively labeled enzyme-substrate complexes revealed a 370-kDa lysergyl peptide synthetase 1 (LPS 1) carrying the amino acid activation domains for alanine, phenylalanine, and proline. The activation of D-lysergic acid is catalyzed by a 140-kDa peptide synthetase (LPS 2) copurifying with LPS 1. LPS 1 and LPS 2 contain 4'-phosphopantetheine and bind their substrates covalently by thioester linkage. Kinetic analysis of the synthesis reaction revealed a Km of approximately 1.4 microM for both D-lysergic acid and its structural homolog dihydrolysergic acid, which is one to two orders of magnitude lower than the Km values for the other amino acids involved. The Km values for the amino acids reflect their relative concentrations in the cellular pool of C. purpurea. This may indicate that in in vivo conditions D-lysergyl peptide formation is limited by the D-lysergic acid concentration in the cell. In vitro, the multienzyme preparation catalyzes the formation of several different D-lysergyl peptide lactams according to the amino acids supplied. Specific antiserum was used to detect LPS 1 in various C. purpurea strains. In C. purpurea wild type, the enzyme was expressed at all stages of cultivation and in different media, suggesting that it is produced constitutively.

  10. Fungal osteomyelitis and septic arthritis.

    Science.gov (United States)

    Bariteau, Jason T; Waryasz, Gregory R; McDonnell, Matthew; Fischer, Staci A; Hayda, Roman A; Born, Christopher T

    2014-06-01

    Management of fungal osteomyelitis and fungal septic arthritis is challenging, especially in the setting of immunodeficiency and conditions that require immunosuppression. Because fungal osteomyelitis and fungal septic arthritis are rare conditions, study of their pathophysiology and treatment has been limited. In the literature, evidence-based treatment is lacking and, historically, outcomes have been poor. The most common offending organisms are Candida and Aspergillus, which are widely distributed in humans and soil. However, some fungal pathogens, such as Histoplasma, Blastomyces, Coccidioides, Cryptococcus, and Sporothrix, have more focal areas of endemicity. Fungal bone and joint infections result from direct inoculation, contiguous infection spread, or hematogenous seeding of organisms. These infections may be difficult to diagnose and eradicate, especially in the setting of total joint arthroplasty. Although there is no clear consensus on treatment, guidelines are available for management of many of these pathogens.

  11. The Epipolythiodiketopiperazine Gene Cluster in Claviceps purpurea: Dysfunctional Cytochrome P450 Enzyme Prevents Formation of the Previously Unknown Clapurines.

    Directory of Open Access Journals (Sweden)

    Julian Dopstadt

    Full Text Available Claviceps purpurea is an important food contaminant and well known for the production of the toxic ergot alkaloids. Apart from that, little is known about its secondary metabolism and not all toxic substances going along with the food contamination with Claviceps are known yet. We explored the metabolite profile of a gene cluster in C. purpurea with a high homology to gene clusters, which are responsible for the formation of epipolythiodiketopiperazine (ETP toxins in other fungi. By overexpressing the transcription factor, we were able to activate the cluster in the standard C. purpurea strain 20.1. Although all necessary genes for the formation of the characteristic disulfide bridge were expressed in the overexpression mutants, the fungus did not produce any ETPs. Isolation of pathway intermediates showed that the common biosynthetic pathway stops after the first steps. Our results demonstrate that hydroxylation of the diketopiperazine backbone is the critical step during the ETP biosynthesis. Due to a dysfunctional enzyme, the fungus is not able to produce toxic ETPs. Instead, the pathway end-products are new unusual metabolites with a unique nitrogen-sulfur bond. By heterologous expression of the Leptosphaeria maculans cytochrome P450 encoding gene sirC, we were able to identify the end-products of the ETP cluster in C. purpurea. The thioclapurines are so far unknown ETPs, which might contribute to the toxicity of other C. purpurea strains with a potentially intact ETP cluster.

  12. The Epipolythiodiketopiperazine Gene Cluster in Claviceps purpurea: Dysfunctional Cytochrome P450 Enzyme Prevents Formation of the Previously Unknown Clapurines

    Science.gov (United States)

    Tudzynski, Paul; Humpf, Hans-Ulrich

    2016-01-01

    Claviceps purpurea is an important food contaminant and well known for the production of the toxic ergot alkaloids. Apart from that, little is known about its secondary metabolism and not all toxic substances going along with the food contamination with Claviceps are known yet. We explored the metabolite profile of a gene cluster in C. purpurea with a high homology to gene clusters, which are responsible for the formation of epipolythiodiketopiperazine (ETP) toxins in other fungi. By overexpressing the transcription factor, we were able to activate the cluster in the standard C. purpurea strain 20.1. Although all necessary genes for the formation of the characteristic disulfide bridge were expressed in the overexpression mutants, the fungus did not produce any ETPs. Isolation of pathway intermediates showed that the common biosynthetic pathway stops after the first steps. Our results demonstrate that hydroxylation of the diketopiperazine backbone is the critical step during the ETP biosynthesis. Due to a dysfunctional enzyme, the fungus is not able to produce toxic ETPs. Instead, the pathway end-products are new unusual metabolites with a unique nitrogen-sulfur bond. By heterologous expression of the Leptosphaeria maculans cytochrome P450 encoding gene sirC, we were able to identify the end-products of the ETP cluster in C. purpurea. The thioclapurines are so far unknown ETPs, which might contribute to the toxicity of other C. purpurea strains with a potentially intact ETP cluster. PMID:27390873

  13. Transcription of Genes in the Biosynthetic Pathway for Fumonisin Mycotoxins Is Epigenetically and Differentially Regulated in the Fungal Maize Pathogen Fusarium verticillioides

    Science.gov (United States)

    Visentin, I.; Montis, V.; Döll, K.; Alabouvette, C.; Tamietti, G.; Karlovsky, P.

    2012-01-01

    When the fungal pathogen Gibberella moniliformis (anamorph, Fusarium verticillioides) colonizes maize and maize-based products, it produces class B fumonisin (FB) mycotoxins, which are a significant threat to human and animal health. FB biosynthetic enzymes and accessory proteins are encoded by a set of clustered and cotranscribed genes collectively named FUM, whose molecular regulation is beginning to be unraveled by researchers. FB accumulation correlates with the amount of transcripts from the key FUM genes, FUM1, FUM21, and FUM8. In fungi in general, gene expression is often partially controlled at the chromatin level in secondary metabolism; when this is the case, the deacetylation and acetylation (and other posttranslational modifications) of histones are usually crucial in the regulation of transcription. To assess whether epigenetic factors regulate the FB pathway, we monitored FB production and FUM1, FUM21, and FUM8 expression in the presence of a histone deacetylase inhibitor and verified by chromatin immunoprecipitation the relative degree of histone acetylation in the promoter regions of FUM1, FUM21, and FUM8 under FB-inducing and noninducing conditions. Moreover, we generated transgenic F. verticillioides strains expressing GFP under the control of the FUM1 promoter to determine whether its strength under FB-inducing and noninducing conditions was influenced by its location in the genome. Our results indicate a clear and differential role for chromatin remodeling in the regulation of FUM genes. This epigenetic regulation can be attained through the modulation of histone acetylation at the level of the promoter regions of the key biosynthetic genes FUM1 and FUM21, but less so for FUM8. PMID:22117026

  14. Bridging the Gap to Non-toxic Fungal Control: Lupinus-Derived Blad-Containing Oligomer as a Novel Candidate to Combat Human Pathogenic Fungi

    Directory of Open Access Journals (Sweden)

    Ana M. Pinheiro

    2017-06-01

    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.

  15. 真菌性角膜炎的病原菌鉴定和药物敏感性分析%The identification and drug susceptibility of pathogens isolated from fungal keratitis

    Institute of Scientific and Technical Information of China (English)

    贺丹; 张晓威; 郝继龙; 万雪; 单秋实; 王丽

    2014-01-01

    Objective To investigate the pathogen species,drug susceptibility and epidemiological characteristics of fungal keratitis in Jilin province,which provide evidence for diagnosis and treatment of clinical infections.Methods Corneal scrapings from 256 patients of suspected fungal infections were collected.Pathogenic fungi were isolated and i-dentified,the drug susceptibility and epidemiological characteristics were analyzed.Results 182 cases were diagnosed as fungal keratitis.Positive rate of fungal culture was 71.1%.A total of 194 fungal strains were isolated.Fusarium spp. (47.0%)was the predominant pathogen,among them,Fusarium solani (32.0%)was the most common isolate.The infections tended to occur in autumn.The majority of patients were male,middle-aged and farmer.Most of them had corneal trauma and treated with medicine before.The main pathogens were sensitive to natamycin.Conclusion Fusari-um spp.,especially Fusarium solani was the predominant pathogen of fungal keratitis in Jilin province.Corneal trauma will increase during the harvest season in autumn,which easily cause the occurrence of fungal keratitis.And natamycin can be used as the preferred drug for the prevention and treatment of fungal keratitis.%目的:了解吉林省真菌性角膜炎的病原菌种类、药物敏感性及流行病学特征,为感染的诊治提供参考依据。方法收集256例疑似真菌感染患者的角膜刮片标本,进行病原真菌的分离、鉴定及药物敏感性检测,并分析流行病学信息。结果有182例患者被诊断为真菌性角膜炎,真菌培养阳性率为71.1%,共分离获得194株真菌菌株。病原菌以镰刀菌属(47.0%)为主,其中茄病镰刀菌最常见(32.0%)。该病多发生在秋季,以男性、中老年、农民居多。多数患者有外伤史和局部用药史。主要病原真菌对纳他霉素均敏感。结论吉林省真菌性角膜炎病原菌以镰刀菌,特别是茄病镰刀菌为主。

  16. JGI Fungal Genomics Program

    Energy Technology Data Exchange (ETDEWEB)

    Grigoriev, Igor V.

    2011-03-14

    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

  17. Fungal Genomics Program

    Energy Technology Data Exchange (ETDEWEB)

    Grigoriev, Igor

    2012-03-12

    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.

  18. Fungal arthritis

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/000444.htm Fungal arthritis To use the sharing features on this page, please enable JavaScript. Fungal arthritis is swelling and irritation (inflammation) of a joint ...

  19. Fungal Meningitis

    Science.gov (United States)

    ... Schedules Preteen & Teen Vaccines Meningococcal Disease Sepsis Fungal Meningitis Language: English Español (Spanish) Recommend on Facebook Tweet ... the brain or spinal cord. Investigation of Fungal Meningitis, 2012 In September 2012, the Centers for Disease ...

  20. NUTRIENT COMPOSITION DEGRADATION OF DAPHNIA PULICARIA BY A HIGHLY PREVALENT CHYTRIDIOMYCETE FUNGAL PATHOGEN (POLYCARYUM LEAVE) DURING NATURALLY OCCURRING LAKE-WIDE EPIDEMICS.

    Science.gov (United States)

    Despite evidence illustrating that chytridiomycete fungal infection can be highly prevalent in Daphnia (>80%) and that infected individuals are preferentially consumed by fish, no studies have measured the nutritional consequences of using chytrid-infected Daphnia as a food sourc...

  1. Genome and secretome analysis of the hemibiotrophic fungal pathogen, Moniliophthora roreri, which causes frosty pod rot disease of cacao: mechanisms of the biotrophic and necrotrophic phases.

    Science.gov (United States)

    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

    2014-02-27

    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

  2. An improved method for RNA extraction from urediniospores of and wheat leaves infected by an obligate fungal pathogen, Puccinia striiformis f. sp.tritici

    Institute of Scientific and Technical Information of China (English)

    MA Li-Jie; QIAO Jia-xing; KONG Xin-yu; WANG Jun-juan; XU Xiang-ming; HU Xiao-ping

    2016-01-01

    Stripe rust, caused byPuccinia striformis f. sp.tritici, is an important wheat disease in China, seriously threatening wheat production. Understanding the winter survival of the fungus is a key for predicting the spring epidemics of the disease, which determines the crop loss. Estimation ofP. striformisf. sp. triticiwinter survival requires processing a large number of samples for sensitive detection of the pathogen in wheat leaf tissue using real-time quantitative reverse transcription PCR (qRT-PCR). A bottleneck for the analysis is the acquisition of a good yield of high quality RNA suitable for qRT-PCR to distinguish dead and alive fungal hyphae inside leaves. Although several methods have been described in the literatures and commercial kits are available for RNA extraction, these methods are mostly too complicated, expensive and inefifcient. Thus, we modiifed three previously reported RNA extraction methods with common and low-cost reagents (LiCl, SDS and NaCl) to solve the problems and selected the best to obtain high quality and quantity RNA for use in qRT-PCR. In the three improved methods, the NaCl method was proven to be the best for extracting RNA from urediniospores of and wheat leaves infected byP. striformisf. sp. tritici, although the modiifed LiCl and SDS methods also increased yield of RNA compared to the previous methods. The improved NaCl method has the folowing advantages: 1) Complete transfer of urediniospores ofP. striformis f. sp. tritici from the mortar and pestle can ensure the initial amount of RNA for the qRT-PCR analysis; 2) the use of low-cost NaCl to replace more expensive Trizol can reduce the cost; 3) the yield and quality of RNA can be increased;4) the improved method is more suitable for a large number and high quantity of samples from ifelds. Using the improved NaCl method, the amount of RNA was increased three times from urediniospores ofP. striformis f. sp. triticicompared from the extraction kit. Approximately, 10.11 μg total

  3. Development and application of a microplate method to evaluate the efficacy of essential oils against Penicillium italicum Wehmer, Penicillium digitatum Sacc. and Colletotrichum musea (Berk. & M.A. Curtis Arx, three postharvest fungal pathogens of fruits

    Directory of Open Access Journals (Sweden)

    Bajji, M.

    2012-01-01

    Full Text Available A microbioassay was developed for evaluating the in vitro antifungal activity of 30 preselected essential oils. A template based on 10 serial dilutions with eight replicates per dilution arranged on two 96-well ELISA plates was used as a reproducible and standardized design to identify the in vitro effectiveness of these essential oils against Penicillium italicum Wehmer, Penicillium digitatum Sacc. and Colletotrichum musea (Berk. & M.A. Curtis Arx, three postharvest fungal pathogens, on fruits. Growth of mycelium was monitored by measuring optical density (492 nm. Cinnamomum zeylanicum, Cinnamomum verum and Eugenia caryophyllus were found to be still active against all the three pathogens even at 100 ppm. Compared to other methods, this microbioassay proved to be a rapid, reproducible, and efficient method for testing the efficacy of essential oils that inhibit spore germination in P. italicum, P. digitatum and C. musea. The assay requires relatively small amounts of essential oils.

  4. Induced systemic resistance and symbiotic performance of peanut plants challenged with fungal pathogens and co-inoculated with the biocontrol agent Bacillus sp. CHEP5 and Bradyrhizobium sp. SEMIA6144.

    Science.gov (United States)

    Figueredo, María Soledad; Tonelli, María Laura; Ibáñez, Fernando; Morla, Federico; Cerioni, Guillermo; Del Carmen Tordable, María; Fabra, Adriana

    2017-04-01

    Synergism between beneficial rhizobacteria and fungal pathogens is poorly understood. Therefore, evaluation of co-inoculation of bacteria that promote plant growth by different mechanisms in pathogen challenged plants would contribute to increase the knowledge about how plants manage interactions with different microorganisms. The goals of this work were a) to elucidate, in greenhouse experiments, the effect of co-inoculation of peanut with Bradyrhizobium sp. SEMIA6144 and the biocontrol agent Bacillus sp. CHEP5 on growth and symbiotic performance of Sclerotium rolfsii challenged plants, and b) to evaluate field performance of these bacteria in co-inoculated peanut plants. The capacity of Bacillus sp. CHEP5 to induce systemic resistance against S. rolfsii was not affected by the inoculation of Bradyrhizobium sp. SEMIA6144. This microsymbiont, protected peanut plants from the S. rolfsii detrimental effect, reducing the stem wilt incidence. However, disease incidence in plants inoculated with the isogenic mutant Bradyrhizobium sp. SEMIA6144 V2 (unable to produce Nod factors) was as high as in pathogen challenged plants. Therefore, Bradyrhizobium sp. SEMIA6144 Nod factors play a role in the systemic resistance against S. rolfsii. Bacillus sp. CHEP5 enhanced Bradyrhizobium sp. SEMIA6144 root surface colonization and improved its symbiotic behavior, even in S. rolfsii challenged plants. Results of field trials confirmed the Bacillus sp. CHEP5 ability to protect against fungal pathogens and to improve the yield of extra-large peanut seeds from 2.15% (in Río Cuarto) to 16.69% (in Las Vertientes), indicating that co-inoculation of beneficial rhizobacteria could be a useful strategy for the peanut production under sustainable agriculture system.

  5. Controlling fungal foliar pathogen e.g. Venturia inaequalis, Blumeriella jaapi, in plants involves treating plants with a composition comprising an extract from Yucca as an antifungal agent

    DEFF Research Database (Denmark)

    2007-01-01

    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...

  6. The USDA Forest Service-RMRS forest fungi collection: Resource for fungal identification, developing biological controls, predicting invasive pathogens, and predicting potential impacts of climate change

    Science.gov (United States)

    Sara M. Ashiglar; John W. Hanna; Amy L. Ross-Davis; Ned B. Klopfenstein

    2014-01-01

    The Moscow Forestry Sciences Laboratory of the Rocky Mountain Research Station (RMRS) has a unique collection of forest/tree-associated fungi with over 15,000 living specimens. Based in Moscow, ID, this USDA APHIS-PPQ (Plant Protection and Quarantine) containment facility houses fungal archives from approximately 35 states and 30 countries. The collection involves the...