Production of cross-kingdom oxylipins by pathogenic fungi: An update on their role in development and pathogenicity.

Science.gov (United States)

Fischer, Gregory J; Keller, Nancy P

2016-03-01

Oxylipins are a class of molecules derived from the incorporation of oxygen into polyunsaturated fatty acid substrates through the action of oxygenases. While extensively investigated in the context of mammalian immune responses, over the last decade it has become apparent that oxylipins are a common means of communication among and between plants, animals, and fungi to control development and alter host-microbe interactions. In fungi, some oxylipins are derived nonenzymatically while others are produced by lipoxygenases, cyclooxygenases, and monooxygenases with homology to plant and human enzymes. Recent investigations of numerous plant and human fungal pathogens have revealed oxylipins to be involved in the establishment and progression of disease. This review highlights oxylipin production by pathogenic fungi and their role in fungal development and pathogen/host interactions.

Combinations of biocontrol agents for management of plant-parasitic nematodes and soilborne plant-pathogenic fungi.

Science.gov (United States)

Meyer, Susan L F; Roberts, Daniel P

2002-03-01

Numerous microbes are antagonistic to plant-parasitic nematodes and soilborne plant-pathogenic fungi, but few of these organisms are commercially available for management of these pathogens. Inconsistent performance of applied biocontrol agents has proven to be a primary obstacle to the development of successful commercial products. One of the strategies for overcoming inconsistent performance is to combine the disease-suppressive activity of two (or more) beneficial microbes in a biocontrol preparation. Such combinations have potential for more extensive colonization of the rhizosphere, more consistent expression of beneficial traits under a broad range of soil conditions, and antagonism to a larger number of plant pests or pathogens than strains applied individually. Conversely, microbes applied in combination also may have antagonistic interactions with each other. Increased, decreased, and unaltered suppression of the target pathogen or pest has been observed when biocontrol microbes have been applied in combination. Unfortunately, the ecological basis for increased or decreased suppression has not been determined in many cases and needs further consideration. The complexity of interactions involved in the application of multiple organisms for biological control has slowed progress toward development of successful formulations. However, this approach has potential for overcoming some of the efficacy problems that occur with application of individual biocontrol agents.

Effect of root exudates of various plants on composition of bacteria and fungi communities with special regard to pathogenic soil-borne fungi

OpenAIRE

Danuta Piętka; Elżbieta Patkowska

2013-01-01

The purpose of the studies conducted in the years 1996 - 1998 was to determine the composition of bacteria and fungi populations in the rhizosphere of winter wheat, spring wheat, soybean and potato, and in non-rhizosphere soil. Besides, the effect of root exudates of these plants on the formation of pathogenic fungi communities was established. The microbiological analysis showed that the greatest tolal number of bacteria was found in the rhizospheres of potato and soybean, and the lowest num...

The Herbivore-Induced Plant Volatiles Methyl Salicylate and Menthol Positively affect Growth and Pathogenicity of Entomopathogenic Fungi

Science.gov (United States)

Lin, Yongwen; Qasim, Muhammad; Hussain, Mubasher; Akutse, Komivi Senyo; Avery, Pasco Bruce; Dash, Chandra Kanta; Wang, Liande

2017-01-01

Some herbivore-induced-plant volatiles (HIPVs) compounds are vital for the functioning of an ecosystem, by triggering multi-trophic interactions for natural enemies, plants and herbivores. However, the effect of these chemicals, which play a crucial role in regulating the multi-trophic interactions between plant-herbivore-entomopathogenic fungi, is still unknown. To fill this scientific gap, we therefore investigated how these chemicals influence the entomopathogenic fungi growth and efficacy. In this study, Lipaphis erysimi induced Arabidopsis thaliana HIPVs were collected using headspace system and detected with GC-MS, and then analyzed the effects of these HIPVs chemicals on Lecanicillium lecanii strain V3450. We found that the HIPVs menthol and methyl salicylate at 1 and 10 nmol·ml-1 improved many performance aspects of the fungus, such as germination, sporulation, appressorial formation as well as its pathogenicity and virulence. These findings are not only important for understanding the multi-trophic interactions in an ecosystem, but also would contribute for developing new and easier procedures for conidial mass production as well as improve the pathogenicity and virulence of entomopathogenic fungi in biological pest management strategies.

In situ hybridization for the detection of rust fungi in paraffin embedded plant tissue sections.

Science.gov (United States)

Ellison, Mitchell A; McMahon, Michael B; Bonde, Morris R; Palmer, Cristi L; Luster, Douglas G

2016-01-01

Rust fungi are obligate pathogens with multiple life stages often including different spore types and multiple plant hosts. While individual rust pathogens are often associated with specific plants, a wide range of plant species are infected with rust fungi. To study the interactions between these important pathogenic fungi and their host plants, one must be able to differentiate fungal tissue from plant tissue. This can be accomplished using the In situ hybridization (ISH) protocol described here. To validate reproducibility using the ISH protocol, samples of Chrysanthemum × morifolium infected with Puccinia horiana, Gladiolus × hortulanus infected with Uromyces transversalis and Glycine max infected with Phakopsora pachyrhizi were tested alongside uninfected leaf tissue samples. The results of these tests show that this technique clearly distinguishes between rust pathogens and their respective host plant tissues. This ISH protocol is applicable to rust fungi and potentially other plant pathogenic fungi as well. It has been shown here that this protocol can be applied to pathogens from different genera of rust fungi with no background staining of plant tissue. We encourage the use of this protocol for the study of plant pathogenic fungi in paraffin embedded sections of host plant tissue.

Lectins in human pathogenic fungi.

Science.gov (United States)

Gallegos, Belém; Martínez, Ruth; Pérez, Laura; Del Socorro Pina, María; Perez, Eduardo; Hernández, Pedro

2014-01-01

Lectins are carbohydrate-binding proteins widely distributed in nature. They constitute a highly diverse group of proteins consisting of many different protein families that are, in general, structurally unrelated. In the last few years, mushroom and other fungal lectins have attracted wide attention due to their antitumour, antiproliferative and immunomodulatory activities. The present mini-review provides concise information about recent developments in understanding lectins from human pathogenic fungi. A bibliographic search was performed in the Science Direct and PubMed databases, using the following keywords "lectin", "fungi", "human" and "pathogenic". Lectins present in fungi have been classified; however, the role played by lectins derived from human pathogenic fungi in infectious processes remains uncertain; thus, this is a scientific field requiring more research. This manuscript is part of the series of works presented at the "V International Workshop: Molecular genetic approaches to the study of human pathogenic fungi" (Oaxaca, Mexico, 2012). Copyright © 2013 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

Fungi pathogenic on wild radish (Raphanus raphanistrum L. in northern Tunisia

Directory of Open Access Journals (Sweden)

N. Djebali

2009-09-01

Full Text Available The distribution and life cycle of wild radish (Raphanus raphanistrum L. and a survey of the pathogens of this plant are reported for the northern regions of Tunisia. Wild radish is a common weed of cereal crops and legumes. It germinates in early autumn (October, develops a rosette stage in November to December after which stem growth, fl owering and pod production occur through to May, with pod maturity completed in June. Fungus isolation from the foliar tissues exhibiting disease symptoms showed that wild radish was infected with the fungi Albugo candida, Alternaria spp. including A. brassicicola, and A. raphani, Erysiphe cruciferarum, Stemphylium herbarum, Peronospora parasitica and Phoma lingam. Ascochyta spp., Cercospora armoraciae, Cladosporium cladosporioides and Colletotrichum higginsianum are here reported from wild radish for the first time. Inoculation tests of pathogens on wild radish plants showed that the most injurious fungi were Alternaria raphani and Phoma lingam. The remaining pathogens were weakly to moderately aggressive on this weed. To access the pathogenic effect of fungi spontaneously infecting natural populations of wild radish, the weed was grown in a field experiment with and without the broad-spectrum systemic fungicide Carbendazim. Results showed a statistically significant two-fold decrease in the number and weight of seed pods in the non-treated plants, indicating that the reproductive potential of wild radish was naturally reduced by fungal infection. Foliar pathogenic fungi have a potential in the integrated weed management of wild radish, this role merits further investigations.

Bioactive Metabolites from Pathogenic and Endophytic Fungi of Forest Trees.

Science.gov (United States)

Masi, Marco; Maddau, Lucia; Linaldeddu, Benedetto Teodoro; Scanu, Bruno; Evidente, Antonio; Cimmino, Alessio

2018-01-01

Fungi play an important role in terrestrial ecosystems interacting positively or negatively with plants. These interactions are complex and the outcomes are different depending on the fungal lifestyles, saprotrophic, mutualistic or pathogenic. Furthermore, fungi are well known for producing secondary metabolites, originating from different biosynthetic pathways, which possess biological properties of considerable biotechnological interest. Among the terrestrial ecosystems, temperate forests represent an enormous reservoir of fungal diversity. This review will highlight the goldmine of secondary metabolites produced by pathogenic and endophytic fungi of forest trees with focus on their biological activities. A structured search of bibliographic databases for peer-reviewed research literature was undertaken using a research discovery application providing access to a large and authoritative source of references. The papers selected were examined and the main results were reported and discussed. Two hundred forthy-one papers were included in the review, outlined a large number of secondary metabolites produced by pathogenic and endophiltic fungi and their biological activities, including phytotoxic, antifungal, antioomycetes, antibacterial, brine shrimp lethality, mosquito biting deterrence and larvicidal, cytotoxic, antiproliferative and many other bioactivities. The findings of this review confirm the importance of secondary metabolites produced by pathogenic and endophytic fungi from forest plants growing in temperate regions as an excellent prospects to discover compounds with new bioactivities and mode of actions. In addition, the potential of some metabolites as a source of new drugs and biopesticides is underlined. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Evolution of structural diversity of trichothecenes, a family of toxins produced by plant pathogenic and entomopathogenic fungi.

Science.gov (United States)

Proctor, Robert H; McCormick, Susan P; Kim, Hye-Seon; Cardoza, Rosa E; Stanley, April M; Lindo, Laura; Kelly, Amy; Brown, Daren W; Lee, Theresa; Vaughan, Martha M; Alexander, Nancy J; Busman, Mark; Gutiérrez, Santiago

2018-04-01

Trichothecenes are a family of terpenoid toxins produced by multiple genera of fungi, including plant and insect pathogens. Some trichothecenes produced by the fungus Fusarium are among the mycotoxins of greatest concern to food and feed safety because of their toxicity and frequent occurrence in cereal crops, and trichothecene production contributes to pathogenesis of some Fusarium species on plants. Collectively, fungi produce over 150 trichothecene analogs: i.e., molecules that share the same core structure but differ in patterns of substituents attached to the core structure. Here, we carried out genomic, phylogenetic, gene-function, and analytical chemistry studies of strains from nine fungal genera to identify genetic variation responsible for trichothecene structural diversity and to gain insight into evolutionary processes that have contributed to the variation. The results indicate that structural diversity has resulted from gain, loss, and functional changes of trichothecene biosynthetic (TRI) genes. The results also indicate that the presence of some substituents has arisen independently in different fungi by gain of different genes with the same function. Variation in TRI gene duplication and number of TRI loci was also observed among the fungi examined, but there was no evidence that such genetic differences have contributed to trichothecene structural variation. We also inferred ancestral states of the TRI cluster and trichothecene biosynthetic pathway, and proposed scenarios for changes in trichothecene structures during divergence of TRI cluster homologs. Together, our findings provide insight into evolutionary processes responsible for structural diversification of toxins produced by pathogenic fungi.

Apyrase inhibitors enhance the ability of diverse fungicides to inhibit the growth of different plant-pathogenic fungi.

Science.gov (United States)

Kumar Tripathy, Manas; Weeraratne, Gayani; Clark, Greg; Roux, Stanley J

2017-09-01

A previous study has demonstrated that the treatment of Arabidopsis plants with chemical inhibitors of apyrase enzymes increases their sensitivity to herbicides. In this study, we found that the addition of the same or related apyrase inhibitors could potentiate the ability of different fungicides to inhibit the growth of five different pathogenic fungi in plate growth assays. The growth of all five fungi was partially inhibited by three commonly used fungicides: copper octanoate, myclobutanil and propiconazole. However, when these fungicides were individually tested in combination with any one of four different apyrase inhibitors (AI.1, AI.10, AI.13 or AI.15), their potency to inhibit the growth of five fungal pathogens was increased significantly relative to their application alone. The apyrase inhibitors were most effective in potentiating the ability of copper octanoate to inhibit fungal growth, and least effective in combination with propiconazole. Among the five pathogens assayed, that most sensitive to the fungicide-potentiating effects of the inhibitors was Sclerotinia sclerotiorum. Overall, among the 60 treatment combinations tested (five pathogens, four apyrase inhibitors, three fungicides), the addition of apyrase inhibitors increased significantly the sensitivity of fungi to the fungicide treatments in 53 of the combinations. Consistent with their predicted mode of action, inhibitors AI.1, AI.10 and AI.13 each increased the level of propiconazole retained in one of the fungi, suggesting that they could partially block the ability of efflux transporters to remove propiconazole from these fungi. © 2016 BSPP AND JOHN WILEY & SONS LTD.

A nitrogen response pathway regulates virulence in plant pathogenic fungi: role of TOR and the bZIP protein MeaB.

Science.gov (United States)

López-Berges, Manuel S; Rispail, Nicolas; Prados-Rosales, Rafael C; Di Pietro, Antonio

2010-12-01

Virulence in plant pathogenic fungi is controlled through a variety of cellular pathways in response to the host environment. Nitrogen limitation has been proposed to act as a key signal to trigger the in planta expression of virulence genes. Moreover, a conserved Pathogenicity mitogen activated protein kinase (MAPK) cascade is strictly required for plant infection in a wide range of pathogens. We investigated the relationship between nitrogen signaling and the Pathogenicity MAPK cascade in controlling infectious growth of the vascular wilt fungus Fusarium oxysporum. Several MAPK-activated virulence functions such as invasive growth, vegetative hyphal fusion and host adhesion were strongly repressed in the presence of the preferred nitrogen source ammonium. Repression of these functions by ammonium was abolished by L-Methionine sulfoximine (MSX) or rapamycin, two specific inhibitors of Gln synthetase and the protein kinase TOR (Target Of Rapamycin), respectively, and was dependent on the bZIP protein MeaB. Supplying tomato plants with ammonium rather than nitrate resulted in a significant delay of vascular wilt symptoms caused by the F. oxysporum wild type strain, but not by the ΔmeaB mutant. Ammonium also repressed invasive growth in two other pathogens, the rice blast fungus Magnaporthe oryzae and the wheat head blight pathogen Fusarium graminearum. Our results suggest the presence of a conserved nitrogen-responsive pathway that operates via TOR and MeaB to control infectious growth in plant pathogenic fungi.

Ubiquity of insect-derived nitrogen transfer to plants by endophytic insect-pathogenic fungi: an additional branch of the soil nitrogen cycle.

Science.gov (United States)

Behie, Scott W; Bidochka, Michael J

2014-03-01

The study of symbiotic nitrogen transfer in soil has largely focused on nitrogen-fixing bacteria. Vascular plants can lose a substantial amount of their nitrogen through insect herbivory. Previously, we showed that plants were able to reacquire nitrogen from insects through a partnership with the endophytic, insect-pathogenic fungus Metarhizium robertsii. That is, the endophytic capability and insect pathogenicity of M. robertsii are coupled so that the fungus acts as a conduit to provide insect-derived nitrogen to plant hosts. Here, we assess the ubiquity of this nitrogen transfer in five Metarhizium species representing those with broad (M. robertsii, M. brunneum, and M. guizhouense) and narrower insect host ranges (M. acridum and M. flavoviride), as well as the insect-pathogenic fungi Beauveria bassiana and Lecanicillium lecanii. Insects were injected with (15)N-labeled nitrogen, and we tracked the incorporation of (15)N into two dicots, haricot bean (Phaseolus vulgaris) and soybean (Glycine max), and two monocots, switchgrass (Panicum virgatum) and wheat (Triticum aestivum), in the presence of these fungi in soil microcosms. All Metarhizium species and B. bassiana but not L. lecanii showed the capacity to transfer nitrogen to plants, although to various degrees. Endophytic association by these fungi increased overall plant productivity. We also showed that in the field, where microbial competition is potentially high, M. robertsii was able to transfer insect-derived nitrogen to plants. Metarhizium spp. and B. bassiana have a worldwide distribution with high soil abundance and may play an important role in the ecological cycling of insect nitrogen back to plant communities.

Oomycetes and fungi: similar weaponry to attack plants

NARCIS (Netherlands)

Latijnhouwers, M.; Wit, de P.J.G.M.; Govers, F.

2003-01-01

Fungi and Oomycetes are the two most important groups of eukaryotic plant pathogens. Fungi form a separate kingdom and are evolutionarily related to animals. Oomycetes are classified in the kingdom Protoctista and are related to heterokont, biflagellate, golden-brown algae. Fundamental differences

Tools to kill: Genome of one of the most destructive plant pathogenic fungi Macrophomina phaseolina

Directory of Open Access Journals (Sweden)

Islam Md

2012-09-01

Full Text Available Abstract Background Macrophomina phaseolina is one of the most destructive necrotrophic fungal pathogens that infect more than 500 plant species throughout the world. It can grow rapidly in infected plants and subsequently produces a large amount of sclerotia that plugs the vessels, resulting in wilting of the plant. Results We sequenced and assembled ~49 Mb into 15 super-scaffolds covering 92.83% of the M. phaseolina genome. We predict 14,249 open reading frames (ORFs of which 9,934 are validated by the transcriptome. This phytopathogen has an abundance of secreted oxidases, peroxidases, and hydrolytic enzymes for degrading cell wall polysaccharides and lignocelluloses to penetrate into the host tissue. To overcome the host plant defense response, M. phaseolina encodes a significant number of P450s, MFS type membrane transporters, glycosidases, transposases, and secondary metabolites in comparison to all sequenced ascomycete species. A strikingly distinct set of carbohydrate esterases (CE are present in M. phaseolina, with the CE9 and CE10 families remarkably higher than any other fungi. The phenotypic microarray data indicates that M. phaseolina can adapt to a wide range of osmotic and pH environments. As a broad host range pathogen, M. phaseolina possesses a large number of pathogen-host interaction genes including those for adhesion, signal transduction, cell wall breakdown, purine biosynthesis, and potent mycotoxin patulin. Conclusions The M. phaseolina genome provides a framework of the infection process at the cytological and molecular level which uses a diverse arsenal of enzymatic and toxin tools to destroy the host plants. Further understanding of the M. phaseolina genome-based plant-pathogen interactions will be instrumental in designing rational strategies for disease control, essential to ensuring global agricultural crop production and security.

Tools to kill: genome of one of the most destructive plant pathogenic fungi Macrophomina phaseolina.

Science.gov (United States)

Islam, Md Shahidul; Haque, Md Samiul; Islam, Mohammad Moinul; Emdad, Emdadul Mannan; Halim, Abdul; Hossen, Quazi Md Mosaddeque; Hossain, Md Zakir; Ahmed, Borhan; Rahim, Sifatur; Rahman, Md Sharifur; Alam, Md Monjurul; Hou, Shaobin; Wan, Xuehua; Saito, Jennifer A; Alam, Maqsudul

2012-09-19

Macrophomina phaseolina is one of the most destructive necrotrophic fungal pathogens that infect more than 500 plant species throughout the world. It can grow rapidly in infected plants and subsequently produces a large amount of sclerotia that plugs the vessels, resulting in wilting of the plant. We sequenced and assembled ~49 Mb into 15 super-scaffolds covering 92.83% of the M. phaseolina genome. We predict 14,249 open reading frames (ORFs) of which 9,934 are validated by the transcriptome. This phytopathogen has an abundance of secreted oxidases, peroxidases, and hydrolytic enzymes for degrading cell wall polysaccharides and lignocelluloses to penetrate into the host tissue. To overcome the host plant defense response, M. phaseolina encodes a significant number of P450s, MFS type membrane transporters, glycosidases, transposases, and secondary metabolites in comparison to all sequenced ascomycete species. A strikingly distinct set of carbohydrate esterases (CE) are present in M. phaseolina, with the CE9 and CE10 families remarkably higher than any other fungi. The phenotypic microarray data indicates that M. phaseolina can adapt to a wide range of osmotic and pH environments. As a broad host range pathogen, M. phaseolina possesses a large number of pathogen-host interaction genes including those for adhesion, signal transduction, cell wall breakdown, purine biosynthesis, and potent mycotoxin patulin. The M. phaseolina genome provides a framework of the infection process at the cytological and molecular level which uses a diverse arsenal of enzymatic and toxin tools to destroy the host plants. Further understanding of the M. phaseolina genome-based plant-pathogen interactions will be instrumental in designing rational strategies for disease control, essential to ensuring global agricultural crop production and security.

Fungi colonizing the soil and roots of tomato (Lycopersicum esculentum Mill. plants treated with biological control agents

Directory of Open Access Journals (Sweden)

Bożena Cwalina-Ambroziak

2012-12-01

Full Text Available Tomato plants, cv. Rumba Ożarowska, grown in the greenhouse of the University of Warmia and Mazury, were protected in the form of alternate spraying (twice and watering (twice with 5% aqueous extracts of the following plant species: Aloe vulgaris Lam., Achillea millefolium L., Mentha piperita L., Polygonum aviculare L., Equisetum arvense L., Juglans regia L. and Urtica dioica L. Plants not treated with the extracts served as control. After fruit harvest, samples of roots and soil were collected. The roots were disinfected and next placed on PDA medium. Soil-colonizing fungi were cultured on Martin medium. Fungi were identified microscopically after incubation. Pathogenic fungal species, Colletotrichum coccodes, Fusarium equiseti, F. oxysporum and F. poae, accounted for over 60% of all isolates obtained from the roots of tomato plants. The soil fungal community was dominated by yeast-like fungi (75.4%, whereas pathogenic fungi were present in low numbers. The applied 5% aqueous plant extracts effectively reduced the abundance of fungi, including pathogenic species, colonizing tomato plants and soil. The extract from P. aviculare showed the highest efficacy, while the extract from J. regia was least effective. Fungi showing antagonistic activity against pathogens (Paecilomyces roseum and species of the genus Trichoderma were isolated in greatest abundance from the soil and the roots of tomato plants treated with A. millefolium, M. piperita and U. dioica extracts.

Dispersal of arbuscular mycorrhizal fungi and plants during succession

Science.gov (United States)

García de León, David; Moora, Mari; Öpik, Maarja; Jairus, Teele; Neuenkamp, Lena; Vasar, Martti; Bueno, C. Guillermo; Gerz, Maret; Davison, John; Zobel, Martin

2016-11-01

Arbuscular mycorrhizal (AM) fungi are important root symbionts that enhance plant nutrient uptake and tolerance to pathogens and drought. While the role of plant dispersal in shaping successional vegetation is well studied, there is very little information about the dispersal abilities of AM fungi. We conducted a trap-box experiment in a recently abandoned quarry at 10 different distances from the quarry edge (i.e. the potential propagule source) over eleven months to assess the short term, within-year, arrival of plant and AM fungal assemblages and hence their dispersal abilities. Using DNA based techniques we identified AM fungal taxa and analyzed their phylogenetic diversity. Plant diversity was determined by transporting trap soil to a greenhouse and identifying emerging seedlings. We recorded 30 AM fungal taxa. These contained a high proportion of ruderal AM fungi (30% of taxa, 79% of sequences) but the richness and abundance of AM fungi were not related to the distance from the presumed propagule source. The number of sequences of AM fungi decreased over time. Twenty seven plant species (30% of them ruderal) were recorded from the soil seed traps. Plant diversity decreased with distance from the propagule source and increased over time. Our data show that AM fungi with ruderal traits can be fast colonizers of early successional habitats.

Comparative analysis of fungal genomes reveals different plant cell wall degrading capacity in fungi

Science.gov (United States)

2013-01-01

Background Fungi produce a variety of carbohydrate activity enzymes (CAZymes) for the degradation of plant polysaccharide materials to facilitate infection and/or gain nutrition. Identifying and comparing CAZymes from fungi with different nutritional modes or infection mechanisms may provide information for better understanding of their life styles and infection models. To date, over hundreds of fungal genomes are publicly available. However, a systematic comparative analysis of fungal CAZymes across the entire fungal kingdom has not been reported. Results In this study, we systemically identified glycoside hydrolases (GHs), polysaccharide lyases (PLs), carbohydrate esterases (CEs), and glycosyltransferases (GTs) as well as carbohydrate-binding modules (CBMs) in the predicted proteomes of 103 representative fungi from Ascomycota, Basidiomycota, Chytridiomycota, and Zygomycota. Comparative analysis of these CAZymes that play major roles in plant polysaccharide degradation revealed that fungi exhibit tremendous diversity in the number and variety of CAZymes. Among them, some families of GHs and CEs are the most prevalent CAZymes that are distributed in all of the fungi analyzed. Importantly, cellulases of some GH families are present in fungi that are not known to have cellulose-degrading ability. In addition, our results also showed that in general, plant pathogenic fungi have the highest number of CAZymes. Biotrophic fungi tend to have fewer CAZymes than necrotrophic and hemibiotrophic fungi. Pathogens of dicots often contain more pectinases than fungi infecting monocots. Interestingly, besides yeasts, many saprophytic fungi that are highly active in degrading plant biomass contain fewer CAZymes than plant pathogenic fungi. Furthermore, analysis of the gene expression profile of the wheat scab fungus Fusarium graminearum revealed that most of the CAZyme genes related to cell wall degradation were up-regulated during plant infection. Phylogenetic analysis also

In situ hybridization for the detection of rust fungi in paraffin embedded plant tissue sections

Science.gov (United States)

Rust fungi infect a wide range of plant species making them of particular interest to plant pathologists. In order to study the interactions between these important pathogenic fungi and their host plants it is useful to be able to differentiate fungal tissue from plant tissue. This can be accomplish...

Chemical constituents from Melodorum fruticosum Lour. flowers against plant pathogenic fungi

Directory of Open Access Journals (Sweden)

Rachsawan Mongkol

2016-07-01

Full Text Available The antifungal activity of hexane, dichloromethane and methanol extracts of 45 Thai plants were in vitro screened against plant phytopathogenic fungi (Alternaria porri, Colletotrichum gloeosporioides, Fusarium oxysporum and Phytophthora parasitica. Seven extracts strongly inhibited the mycelial growth of fungi. The plant extracts with highest antifungal activity were Limnophila aromatic, Eupatorium odoratum, Melodorum fruticosum and Alpinia galanga with 70%, 58%, 74% and 100% inhibition, respectively. The potent dichloromethane extract from M. fruticosum flowers was separated using bioassay guided against P. parasitica. Eight compounds: 1-hexacosanol (1, 5-hydroxy-7-methoxyflavone (2, β-sitosterol (3, melodorinone B (4, benzoic acid (5, chrysin (6, melodorinol (7 and melodorinone A (8 could be isolated. Among the isolated compounds, benzoic acid (5 and melodorinol (7 exhibited strong activity against mycelial growth of P. parasitica at 100% and 93% inhibition with the half maximal inhibitory concentration (IC50 values of 108 μg/mL and 130 μg/mL, respectively. This plant could be exploited for eco-friendly management control of plant diseases.

Contrasting effects of necrotrophic and biotrophic plant pathogens on the aphid Aphis fabae

OpenAIRE

Al-Naemi, F.; Hatcher, P. E.

2013-01-01

Phytophagous insects have to contend with a wide variation in food quality brought about by a variety of factors intrinsic and extrinsic to the plant. One of the most important factors is infection by plant pathogenic fungi. Necrotrophic and biotrophic plant pathogenic fungi may have contrasting effects on insect herbivores due to their different infection mechanisms and induction of different resistance pathways, although this has been little studied and there has been no study of their comb...

Functional analysis of the conserved transcriptional regulator CfWor1 in Cladosporium fulvum reveals diverse roles in the virulence of plant pathogenic fungi

NARCIS (Netherlands)

Ökmen, B.; Collemare, J.; Griffiths, S.A.; Burgt, van der A.; Cox, R.; Wit, de P.J.G.M.

2014-01-01

Fungal Wor1-like proteins are conserved transcriptional regulators that are reported to regulate the virulence of several plant pathogenic fungi by affecting the expression of virulence genes. Here, we report the functional analysis of CfWor1, the homologue of Wor1 in Cladosporium fulvum. ¿cfwor1

Antifungal activity of nettle (Urtica dioica L.), colocynth (Citrullus colocynthis L. Schrad), oleander (Nerium oleander L.) and konar (Ziziphus spina-christi L.) extracts on plants pathogenic fungi.

Science.gov (United States)

Hadizadeh, I; Peivastegan, B; Kolahi, M

2009-01-01

Anti-mycotic activity of the ethanol extracts from Nettle (Urtica dioica L.), Colocynth (Citrullus colocynthis L. Schrad), Konar (Ziziphus spina-christi L.) and Oleander (Nerium oleander L.) floral parts were screened in vitro against four important plant pathogenic fungi viz.; Alternaria alternate, Fusarium oxysporum, Fusarium solani and Rizoctonia solani using agar dilution bioassay. Extracts showed antifungal activity against all the tested fungi. Among the plants, Nettle and Colocynth were the most effective against A. alternate and R. solani while Oleander possesses the best inhibition on F. oxysporum and F. solani. Konar was the most effective extract by reducing the growth of Rizoctonia solani than other fungi. These results showed that extracts could be considered suitable alternatives to chemical additives for the control of fungal diseases in plants.

Evolution and genome architecture in fungal plant pathogens.

Science.gov (United States)

Möller, Mareike; Stukenbrock, Eva H

2017-12-01

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.

The microscopic pathogenic fungi of the Łęczna-Włodawa Lake District. I. The occurrence of pathogenic fungi in plant communities and theirs phenology

Directory of Open Access Journals (Sweden)

Wiesław Mułenko

2014-08-01

Full Text Available The paper presents the results of the studies on tbe occurrence and phenology of puthogenic fungi in plant communities of the Łęczna-Włodawa Lake District in 1981-1984. The taxonomic list of collected fungi species will be published in another paper.

Response of root fungi in Pisum sativum to plant and soil environmental factors

DEFF Research Database (Denmark)

Yu, Lingling

and nutritional status of the plant and soil environments. However, limited information is available about the richness and composition of most of these root-associated fungi as studies of fungal communities remain a challenge because of below-ground high taxonomic and ecological diversity. In the present study......; thus obligate biotrophic fungi and saprotrophic fungi were markedly increased with organic fertilizer dosages, while root pathogenic fungi were decreased with organic amendments. In conclusion, the present work has shown that root-associated fungal community structure relate to plant and soil...... environmental factors. The obtained knowledge from this study can provide novel information of communities of root-associated fungi; thus improving the basic understanding of plant-root fungi-environment interactions in agroecosystems....

Investigating Gene Function in Cereal Rust Fungi by Plant-Mediated Virus-Induced Gene Silencing.

Science.gov (United States)

Panwar, Vinay; Bakkeren, Guus

2017-01-01

Cereal rust fungi are destructive pathogens, threatening grain production worldwide. Targeted breeding for resistance utilizing host resistance genes has been effective. However, breakdown of resistance occurs frequently and continued efforts are needed to understand how these fungi overcome resistance and to expand the range of available resistance genes. Whole genome sequencing, transcriptomic and proteomic studies followed by genome-wide computational and comparative analyses have identified large repertoire of genes in rust fungi among which are candidates predicted to code for pathogenicity and virulence factors. Some of these genes represent defence triggering avirulence effectors. However, functions of most genes still needs to be assessed to understand the biology of these obligate biotrophic pathogens. Since genetic manipulations such as gene deletion and genetic transformation are not yet feasible in rust fungi, performing functional gene studies is challenging. Recently, Host-induced gene silencing (HIGS) has emerged as a useful tool to characterize gene function in rust fungi while infecting and growing in host plants. We utilized Barley stripe mosaic virus-mediated virus induced gene silencing (BSMV-VIGS) to induce HIGS of candidate rust fungal genes in the wheat host to determine their role in plant-fungal interactions. Here, we describe the methods for using BSMV-VIGS in wheat for functional genomics study in cereal rust fungi.

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

Ecology and Genomic Insights into Plant-Pathogenic and Plant-Nonpathogenic Endophytes.

Science.gov (United States)

Brader, Günter; Compant, Stéphane; Vescio, Kathryn; Mitter, Birgit; Trognitz, Friederike; Ma, Li-Jun; Sessitsch, Angela

2017-08-04

Plants are colonized on their surfaces and in the rhizosphere and phyllosphere by a multitude of different microorganisms and are inhabited internally by endophytes. Most endophytes act as commensals without any known effect on their plant host, but multiple bacteria and fungi establish a mutualistic relationship with plants, and some act as pathogens. The outcome of these plant-microbe interactions depends on biotic and abiotic environmental factors and on the genotype of the host and the interacting microorganism. In addition, endophytic microbiota and the manifold interactions between members, including pathogens, have a profound influence on the function of the system plant and the development of pathobiomes. In this review, we elaborate on the differences and similarities between nonpathogenic and pathogenic endophytes in terms of host plant response, colonization strategy, and genome content. We furthermore discuss environmental effects and biotic interactions within plant microbiota that influence pathogenesis and the pathobiome.

Specific interactions between arbuscular mycorrhizal fungi and plant growth-promoting bacteria--as revealed by different combinations

Energy Technology Data Exchange (ETDEWEB)

Jaderlund, Lotta; Arthurson, Veronica; Granhall, Ulf; Jansson, Janet K.

2008-05-15

The interactions between two plant growth promoting rhizobacteria (PGPR), Pseudomonas fluorescens SBW25 and Paenibacillus brasilensis PB177, two arbuscular mycorrhizal (AM) fungi (Glomus mosseae and G. intraradices) and one pathogenic fungus (Microdochium nivale) were investigated on winter wheat (Triticum aestivum cultivar Tarso) in a greenhouse trial. PB177, but not SBW25, had strong inhibitory effects on M. nivale in dual culture plate assays. The results from the greenhouse experiment show very specific interactions; e.g. the two AM fungi react differently when interacting with the same bacteria on plants. G. intraradices (single inoculation or together with SBW25) increased plant dry weight on M. nivale infested plants, suggesting that the pathogenic fungus is counteracted by G. intraradices, but PB177 inhibited this positive effect. This is an example of two completely different reactions between the same AM fungus and two species of bacteria, previously known to enhance plant growth and inhibit pathogens. When searching for plant growth promoting microorganisms it is therefore important to test for the most suitable combination of plant, bacteria and fungi in order to get satisfactory plant growth benefits.

Biosensors for plant pathogen detection.

Science.gov (United States)

Khater, Mohga; de la Escosura-Muñiz, Alfredo; Merkoçi, Arben

2017-07-15

Infectious plant diseases are caused by pathogenic microorganisms such as fungi, bacteria, viruses, viroids, phytoplasma and nematodes. Worldwide, plant pathogen infections are among main factors limiting crop productivity and increasing economic losses. Plant pathogen detection is important as first step to manage a plant disease in greenhouses, field conditions and at the country boarders. Current immunological techniques used to detect pathogens in plant include enzyme-linked immunosorbent assays (ELISA) and direct tissue blot immunoassays (DTBIA). DNA-based techniques such as polymerase chain reaction (PCR), real time PCR (RT-PCR) and dot blot hybridization have also been proposed for pathogen identification and detection. However these methodologies are time-consuming and require complex instruments, being not suitable for in-situ analysis. Consequently, there is strong interest for developing new biosensing systems for early detection of plant diseases with high sensitivity and specificity at the point-of-care. In this context, we revise here the recent advancement in the development of advantageous biosensing systems for plant pathogen detection based on both antibody and DNA receptors. The use of different nanomaterials such as nanochannels and metallic nanoparticles for the development of innovative and sensitive biosensing systems for the detection of pathogens (i.e. bacteria and viruses) at the point-of-care is also shown. Plastic and paper-based platforms have been used for this purpose, offering cheap and easy-to-use really integrated sensing systems for rapid on-site detection. Beside devices developed at research and development level a brief revision of commercially available kits is also included in this review. Copyright © 2016 Elsevier B.V. All rights reserved.

Distribution and antimicrobial potential of endophytic fungi associated with ethnomedicinal plant Melastoma malabathricum L.

Science.gov (United States)

Mishra, Vineet Kumar; Singh, Garima; Passari, Ajit Kumar; Yadav, Mukesh Kumar; Gupta, Vijai Kumar; Singh, Bhim Pratap

2016-03-01

Distributions of endophytic fungi associated with ethnomedicinal plant Melastoma malabathricum L. was studied and 91 isolates belonging to 18 genera were recovered. The isolates were distributed to sordariomycetes (62.63%), dothideomycetes (19.78%), eurotiomycetes (7.69%), zygomycetes (4.19%), agaricomycetes (1.09%), and mycelia sterilia (4.39%). Based on colony morphology and examination of spores, the isolates were classified into 18 taxa, of which Colletotrichum, Phomopsis and Phoma were dominant, their relative frequencies were 23.07%, 17.58% and 12.08% respectively. The colonization rate of endophytic fungi was determined and found to be significantly higher in leaf segments (50.76%), followed by root (41.53%) and stem tissues (27.69%). All the isolates were screened for antimicrobial activity and revealed that 26.37% endophytic fungi were active against one or more pathogens. Twenty four isolates showing significant antimicrobial activity were identified by sequencing the ITS1-5.8S-ITS2 region of rRNA gene. Results indicated that endophytic fungi associated with leaf were functionally versatile as they showed antimicrobial activity against most of the tested pathogens. The endophytic fungi Diaporthe phaseolorum var. meridionalis (KF193982) inhibited all the tested bacterial pathogens, whereas, Penicillium chermesinum (KM405640) displayed most significant antifungal activity. This seems to be the first hand report to understand the distribution and antimicrobial ability of endophytic fungi from ethno-medicinal plant M. malabathricum.

Friend or foe? Evolutionary history of glycoside hydrolase family 32 genes encoding for sucrolytic activity in fungi and its implications for plant-fungal symbioses

Directory of Open Access Journals (Sweden)

James Timothy Y

2009-06-01

Full Text Available Abstract Background Many fungi are obligate biotrophs of plants, growing in live plant tissues, gaining direct access to recently photosynthesized carbon. Photosynthate within plants is transported from source to sink tissues as sucrose, which is hydrolyzed by plant glycosyl hydrolase family 32 enzymes (GH32 into its constituent monosaccharides to meet plant cellular demands. A number of plant pathogenic fungi also use GH32 enzymes to access plant-derived sucrose, but less is known about the sucrose utilization ability of mutualistic and commensal plant biotrophic fungi, such as mycorrhizal and endophytic fungi. The aim of this study was to explore the distribution and abundance of GH32 genes in fungi to understand how sucrose utilization is structured within and among major ecological guilds and evolutionary lineages. Using bioinformatic and PCR-based analyses, we tested for GH32 gene presence in all available fungal genomes and an additional 149 species representing a broad phylogenetic and ecological range of biotrophic fungi. Results We detected 9 lineages of GH32 genes in fungi, 4 of which we describe for the first time. GH32 gene number in fungal genomes ranged from 0–12. Ancestral state reconstruction of GH32 gene abundance showed a strong correlation with nutritional mode, and gene family expansion was observed in several clades of pathogenic filamentous Ascomycota species. GH32 gene number was negatively correlated with animal pathogenicity and positively correlated with plant biotrophy, with the notable exception of mycorrhizal taxa. Few mycorrhizal species were found to have GH32 genes as compared to other guilds of plant-associated fungi, such as pathogens, endophytes and lichen-forming fungi. GH32 genes were also more prevalent in the Ascomycota than in the Basidiomycota. Conclusion We found a strong signature of both ecological strategy and phylogeny on GH32 gene number in fungi. These data suggest that plant biotrophic fungi

Fungi of the genus Fusarium as pathogens of soybean seedlings

Directory of Open Access Journals (Sweden)

Joanna Marcinkowska

2013-12-01

Full Text Available Twenty isolates of fungi of the genus Fusarium collected in the period 1980-1982 from various organs of diseased soybean plants were investigated. Eight of them proved pathogenic to soybean seedlings. The species F. culmorum was most numerously represented among the isolated (4 of 8 pathogens. Isolates of F. sambucinum were also pathogenic (2 of 4 and those of F. soloni (1 of 3, too. The only isolate of F. avenaceum also caused seedling blight. Two isolates of F. oxysporum and two of F. arthrosporioides were not pathogenic. Numerous isolates affected seed gernination and one greatly inhibited growth of the infected seedlings. Pathogenicity was tested in the laboratory in Petri plates on isolate cultures and on filter paper imbibed with fungal inoculum and, in the greenhouse on a peat and perlite substrate. The degree of infection and the character of the disease symptoms depended on the experimental conditions. The results of experiments in plates and in the greenhouse supplemented one another.

USE OF SAPROPHYTIC FUNGI SPECIMENS AS A PLANT PROTECTION AGENTS IN TOMATOE PLANTATION

Directory of Open Access Journals (Sweden)

Katarzyna Bandurska

2015-07-01

Full Text Available The purpose of this study was to determine the effects of the Trichoderma spp. fungi on the conditions and health of tomato plants. The experiments were conducted in pot cultures and controlled conditions. Commercial formula TRIFENDER containing Trichoderma asperellum spores and isolated from garden soil strain T12 Trichoderma viride were used. In one embodiment, the plants were treated with pathogenic strain of Fusarium sp. that commonly damages crops and against which the whole arsenal of chemicals is used. Preparations obtained from isolated and multiplied fungal cultures were used for the treatment of the above-ground (spraying and under-ground (sprinkling parts of tomatoes. Influence of the Trichoderma fungi was determined by comparing the presence of necrosis on leaves in various groups of cultivated tomatoes compared to control samples. The development of seedlings was checked by measuring the length of plants and the weight of fresh and dry plants. The results demonstrated the protective role of Trichoderma spp. fungi in relation to the Fusarium sp.. Leaves of tomato treated with solutions of saprophytic fungi had a statistically significant lower amount of necrotic changes caused by the pathogen. More effective in this regard was uncommercial isolate of T. viride. Formulation used in the experiments Trifender and isolate T. viride statistically significant influence on the growth and development of the tomato plants as evidenced by increased compared to the control fresh and dry weight of plants.

Cotton plants export microRNAs to inhibit virulence gene expression in a fungal pathogen.

Science.gov (United States)

Zhang, Tao; Zhao, Yun-Long; Zhao, Jian-Hua; Wang, Sheng; Jin, Yun; Chen, Zhong-Qi; Fang, Yuan-Yuan; Hua, Chen-Lei; Ding, Shou-Wei; Guo, Hui-Shan

2016-09-26

Plant pathogenic fungi represent the largest group of disease-causing agents on crop plants, and are a constant and major threat to agriculture worldwide. Recent studies have shown that engineered production of RNA interference (RNAi)-inducing dsRNA in host plants can trigger specific fungal gene silencing and confer resistance to fungal pathogens 1-7 . Although these findings illustrate efficient uptake of host RNAi triggers by pathogenic fungi, it is unknown whether or not such an uptake mechanism has been evolved for a natural biological function in fungus-host interactions. Here, we show that in response to infection with Verticillium dahliae (a vascular fungal pathogen responsible for devastating wilt diseases in many crops) cotton plants increase production of microRNA 166 (miR166) and miR159 and export both to the fungal hyphae for specific silencing. We found that two V. dahliae genes encoding a Ca 2+ -dependent cysteine protease (Clp-1) and an isotrichodermin C-15 hydroxylase (HiC-15), and targeted by miR166 and miR159, respectively, are both essential for fungal virulence. Notably, V. dahliae strains expressing either Clp-1 or HiC-15 rendered resistant to the respective miRNA exhibited drastically enhanced virulence in cotton plants. Together, our findings identify a novel defence strategy of host plants by exporting specific miRNAs to induce cross-kingdom gene silencing in pathogenic fungi and confer disease resistance.

Molecular mimicry modulates plant host responses to pathogens.

Science.gov (United States)

Ronald, Pamela; Joe, Anna

2018-01-25

Pathogens often secrete molecules that mimic those present in the plant host. Recent studies indicate that some of these molecules mimic plant hormones required for development and immunity. This Viewpoint reviews the literature on microbial molecules produced by plant pathogens that functionally mimic molecules present in the plant host. This article includes examples from nematodes, bacteria and fungi with emphasis on RaxX, a microbial protein produced by the bacterial pathogen Xanthomonas oryzae pv. oryzae. RaxX mimics a plant peptide hormone, PSY (plant peptide containing sulphated tyrosine). The rice immune receptor XA21 detects sulphated RaxX but not the endogenous peptide PSY. Studies of the RaxX/XA21 system have provided insight into both host and pathogen biology and offered a framework for future work directed at understanding how XA21 and the PSY receptor(s) can be differentially activated by RaxX and endogenous PSY peptides. © The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

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.

Comparative genomics and the evolution of pathogenicity in human pathogenic fungi.

LENUS (Irish Health Repository)

Moran, Gary P

2011-01-01

Because most fungi have evolved to be free-living in the environment and because the infections they cause are usually opportunistic in nature, it is often difficult to identify specific traits that contribute to fungal pathogenesis. In recent years, there has been a surge in the number of sequenced genomes of human fungal pathogens, and comparison of these sequences has proved to be an excellent resource for exploring commonalities and differences in how these species interact with their hosts. In order to survive in the human body, fungi must be able to adapt to new nutrient sources and environmental stresses. Therefore, genes involved in carbohydrate and amino acid metabolism and transport and genes encoding secondary metabolites tend to be overrepresented in pathogenic species (e.g., Aspergillus fumigatus). However, it is clear that human commensal yeast species such as Candida albicans have also evolved a range of specific factors that facilitate direct interaction with host tissues. The evolution of virulence across the human pathogenic fungi has occurred largely through very similar mechanisms. One of the most important mechanisms is gene duplication and the expansion of gene families, particularly in subtelomeric regions. Unlike the case for prokaryotic pathogens, horizontal transfer of genes between species and other genera does not seem to have played a significant role in the evolution of fungal virulence. New sequencing technologies promise the prospect of even greater numbers of genome sequences, facilitating the sequencing of multiple genomes and transcriptomes within individual species, and will undoubtedly contribute to a deeper insight into fungal pathogenesis.

Characterization of Novel Di-, Tri-, and Tetranucleotide Microsatellite Primers Suitable for Genotyping Various Plant Pathogenic Fungi with Special Emphasis on Fusaria and Mycospherella graminicola

Directory of Open Access Journals (Sweden)

Joseph-Alexander Verreet

2012-03-01

Full Text Available The goals of this investigation were to identify and evaluate the use of polymorphic microsatellite marker (PMM analysis for molecular typing of seventeen plant pathogenic fungi. Primers for di-, tri-, and tetranucleotide loci were designed directly from the recently published genomic sequence of Mycospherlla graminicola and Fusarium graminearum. A total of 20 new microsatellite primers as easy-to-score markers were developed. Microsatellite primer PCR (MP-PCR yielded highly reproducible and complex genomic fingerprints, with several bands ranging in size from 200 to 3000 bp. Of the 20 primers tested, only (TAGG4, (TCC5 and (CA7T produced a high number of polymorphic bands from either F. graminearum or F. culmorum. (ATG5 led to successful amplifications in M. graminicola isolates collected from Germany. Percentage of polymorphic bands among Fusarium species ranged from 9 to 100%. Cluster analysis of banding patterns of the isolates corresponded well to the established species delineations based on morphology and other methods of phylogenetic analysis. The current research demonstrates that the newly designed microsatellite primers are reliable, sensitive and technically simple tools for assaying genetic variability in plant pathogenic fungi.

Correction: Comparative analysis of fungal genomes reveals different plant cell wall degrading capacity in fungi

Science.gov (United States)

2014-01-01

. Importantly, cellulases of some GH families are present in fungi that are not known to have cellulose-degrading ability. In addition, our results also showed that in general, plant pathogenic fungi have the highest number of CAZymes. Biotrophic fungi tend to have fewer CAZymes than necrotrophic and hemibiotrophic fungi. Pathogens of dicots often contain more pectinases than fungi infecting monocots. Interestingly, besides yeasts, many saprophytic fungi that are highly active in degrading plant biomass contain fewer CAZymes than plant pathogenic fungi. Furthermore, analysis of the gene expression profile of the wheat scab fungus Fusarium graminearum revealed that most of the CAZyme genes related to cell wall degradation were up-regulated during plant infection. Phylogenetic analysis also revealed a complex history of lineage-specific expansions and attritions for the PL1 family. Conclusions Our study provides insights into the variety and expansion of fungal CAZyme classes and revealed the relationship of CAZyme size and diversity with their nutritional strategy and host specificity. PMID:24422981

The Top 10 fungal pathogens in molecular plant pathology.

Science.gov (United States)

Dean, Ralph; Van Kan, Jan A L; Pretorius, Zacharias A; Hammond-Kosack, Kim E; Di Pietro, Antonio; Spanu, Pietro D; Rudd, Jason J; Dickman, Marty; Kahmann, Regine; Ellis, Jeff; Foster, Gary D

2012-05-01

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 community, and resulted in the generation of a Top 10 fungal plant pathogen list for Molecular Plant Pathology. The Top 10 list includes, in rank order, (1) Magnaporthe oryzae; (2) Botrytis cinerea; (3) Puccinia spp.; (4) Fusarium graminearum; (5) Fusarium oxysporum; (6) Blumeria graminis; (7) Mycosphaerella graminicola; (8) Colletotrichum spp.; (9) Ustilago maydis; (10) Melampsora lini, with honourable mentions for fungi just missing out on the Top 10, including Phakopsora pachyrhizi and Rhizoctonia solani. This article presents a short resumé of each fungus in the Top 10 list and its importance, with the intent of initiating discussion and debate amongst the plant mycology community, as well as laying down a bench-mark. It will be interesting to see in future years how perceptions change and what fungi will comprise any future Top 10. © 2012 THE AUTHORS. MOLECULAR PLANT PATHOLOGY © 2012 BSPP AND BLACKWELL PUBLISHING LTD.

Nutrient acquisition and secondary metabolites in plant pathogenic fungi

DEFF Research Database (Denmark)

Droce, Aida

Fusarium graminearum is a necrotrophic plant pathogen that leads to severe infections of cereals contaminating them with mycotoxins harmful to human and animal. Blumeria graminis f. sp. hordei is an obligate biotroph that causes powdery mildew infections of barley. In this thesis, lifecycles and ...

Fungi

DEFF Research Database (Denmark)

Hajek, Ann E.; Meyling, Nicolai Vitt

2018-01-01

been the focus of most ecological research. Some taxa of invertebrate pathogenic fungi have evolved adaptations for utilizing living plants as substrates, and these lifestyles have recently received increased attention from researchers following the initial documentations of such plant associations...

Swainsonine Biosynthesis Genes in Diverse Symbiotic and Pathogenic Fungi

Directory of Open Access Journals (Sweden)

Daniel Cook

2017-06-01

Full Text Available Swainsonine—a cytotoxic fungal alkaloid and a potential cancer therapy drug—is produced by the insect pathogen and plant symbiont Metarhizium robertsii, the clover pathogen Slafractonia leguminicola, locoweed symbionts belonging to Alternaria sect. Undifilum, and a recently discovered morning glory symbiont belonging to order Chaetothyriales. Genome sequence analyses revealed that these fungi share orthologous gene clusters, designated “SWN,” which included a multifunctional swnK gene comprising predicted adenylylation and acyltransferase domains with their associated thiolation domains, a β-ketoacyl synthase domain, and two reductase domains. The role of swnK was demonstrated by inactivating it in M. robertsii through homologous gene replacement to give a ∆swnK mutant that produced no detectable swainsonine, then complementing the mutant with the wild-type gene to restore swainsonine biosynthesis. Other SWN cluster genes were predicted to encode two putative hydroxylases and two reductases, as expected to complete biosynthesis of swainsonine from the predicted SwnK product. SWN gene clusters were identified in six out of seven sequenced genomes of Metarhzium species, and in all 15 sequenced genomes of Arthrodermataceae, a family of fungi that cause athlete’s foot and ringworm diseases in humans and other mammals. Representative isolates of all of these species were cultured, and all Metarhizium spp. with SWN clusters, as well as all but one of the Arthrodermataceae, produced swainsonine. These results suggest a new biosynthetic hypothesis for this alkaloid, extending the known taxonomic breadth of swainsonine producers to at least four orders of Ascomycota, and suggest that swainsonine has roles in mutualistic symbioses and diseases of plants and animals.

Succession of root-associated fungi in Pisum sativum during a plant growth cycle as examined by 454 pyrosequencing

DEFF Research Database (Denmark)

Yu, L.; Nicolaisen, M.; Larsen, J.

2012-01-01

Purpose Roots are inhabited by a broad range of fungi, including pathogens and mycorrhizal fungi, with functional traits related to plant health and nutrition. Management of these fungi in agroecosystems requires profound knowledge about their ecology. The main objective of this study was to exam...

(Cucumis melo L.) cultivars to soil-borne plant pathogenic fungi in Iran

African Journals Online (AJOL)

ajl11

2012-10-30

Oct 30, 2012 ... resistance of melon cultivars to three important soil-borne plant pathogens found worldwide. Key words: Melon ... use of cultivars resistant to plant diseases is one of the ..... emerging disease of melons worldwide. Plant Dis.

Diverse Lifestyles and Strategies of Plant Pathogenesis Encoded in the Genomes of Eighteen Doethideomycetes Fungi

Energy Technology Data Exchange (ETDEWEB)

Ohm, Robin A.; Feau, Nicolas; Henrissat, Bernard; Schoch, Conrad L.; Horwitz, Benjamin A.; Barry, Kerrie W.; Condon, Bradford J.; Copeland, Alex C.; Dhillon, Braham; Glaser, Fabien; Hesse, Cedar N.; Kosti, Idit; LaButti, Kurt; Lindquist, Erika A.; Lucas, Susan; Salamov, Asaf A.; Bradshaw, Rosie E.; Ciuffetti, Lynda; Hamelin, Richard C.; Kema, Gert H. J.; Lawrence, Christopher; Scott, James A.; Spatafora, Joseph W.; Turgeon, B. Gillian; de Wit, Pierre J. G. M.; Zhong, Shaobin; Goodwin, Stephen B.; Grigoriev, Igor V.

2012-03-13

The class of Dothideomycetes is one of the largest and most diverse groups of fungi. Many are plant pathogens and pose a serious threat to agricultural crops grown for biofuel, food or feed. Most Dothideomycetes have only a single host and related species can have very diverse host plants. Eighteen genomes of Dothideomycetes have currently been sequenced by the Joint Genome Institute and other sequencing centers. Here we describe the results of comparative analyses of the fungi in this group.

Advances in Genomics of Entomopathogenic Fungi.

Science.gov (United States)

Wang, J B; St Leger, R J; Wang, C

2016-01-01

Fungi are the commonest pathogens of insects and crucial regulators of insect populations. The rapid advance of genome technologies has revolutionized our understanding of entomopathogenic fungi with multiple Metarhizium spp. sequenced, as well as Beauveria bassiana, Cordyceps militaris, and Ophiocordyceps sinensis among others. Phylogenomic analysis suggests that the ancestors of many of these fungi were plant endophytes or pathogens, with entomopathogenicity being an acquired characteristic. These fungi now occupy a wide range of habitats and hosts, and their genomes have provided a wealth of information on the evolution of virulence-related characteristics, as well as the protein families and genomic structure associated with ecological and econutritional heterogeneity, genome evolution, and host range diversification. In particular, their evolutionary transition from plant pathogens or endophytes to insect pathogens provides a novel perspective on how new functional mechanisms important for host switching and virulence are acquired. Importantly, genomic resources have helped make entomopathogenic fungi ideal model systems for answering basic questions in parasitology, entomology, and speciation. At the same time, identifying the selective forces that act upon entomopathogen fitness traits could underpin both the development of new mycoinsecticides and further our understanding of the natural roles of these fungi in nature. These roles frequently include mutualistic relationships with plants. Genomics has also facilitated the rapid identification of genes encoding biologically useful molecules, with implications for the development of pharmaceuticals and the use of these fungi as bioreactors. Copyright © 2016 Elsevier Inc. All rights reserved.

Plant pathogens as biocontrol agents of Cirsium arvense – an overestimated approach?

Directory of Open Access Journals (Sweden)

Esther Müller

2011-11-01

Full Text Available Cirsium arvense is one of the worst weeds in agriculture. As herbicides are not very effective and not accepted by organic farming and special habitats, possible biocontrol agents have been investigated since many decades. In particular plant pathogens of C. arvense have received considerable interest and have been promoted as “mycoherbicides” or “bioherbicides”. A total of 10 fungi and one bacterium have been proposed and tested as biocontrol agents against C. arvense. A variety of experiments analysed the noxious influence of spores or other parts of living fungi or bacteria on plants while others used fungal or bacterial products, usually toxins. Also combinations of spores with herbicides and combinations of several pathogens were tested. All approaches turned out to be inappropriate with regard to target plant specificity, effectiveness and application possibilities. As yet, none of the tested species or substances has achieved marketability, despite two patents on the use of Septoria cirsii and Phomopsis cirsii. We conclude that the potential of pathogens for biocontrol of C. arvense has largely been overestimated.

Poly(lactic-co-glycolic) acid nanoparticles uptake by Vitis vinifera and grapevine-pathogenic fungi

International Nuclear Information System (INIS)

Valletta, Alessio; Chronopoulou, Laura; Palocci, Cleofe; Baldan, Barbara; Donati, Livia; Pasqua, Gabriella

2014-01-01

Poly(lactic-co-glycolic) acid (PLGA)-based NPs are currently considered among the most promising drug carriers, nevertheless their use in plants has never been investigated. In this work, for the first time, we demonstrated the ability of PLGA NPs to cross the plant cell wall and membrane of Vitis vinifera cell cultures and grapevine-pathogenic fungi. By means of fluorescence microscopy, we established that PLGA NPs can enter in grapevine leaf tissues through stomata openings and that they can be absorbed by the roots and transported to the shoot through vascular tissues. TEM analysis on cultured cells showed that NPs ≤ 50 nm could enter cells, while bigger ones remained attached to the cell wall. Viability tests demonstrated that PLGA NPs were not cytotoxic for V. vinifera-cultured cells. The cellular uptake of PLGA NPs by some important grapevine-pathogenic fungi has also been observed, thus suggesting that PLGA NPs could be used to deliver antifungal compounds within fungal cells. Overall the results reported suggest that such NPs may play a key role in future developments of agrobiotechnologies, as it is currently happening in biomedicine

Poly(lactic-co-glycolic) acid nanoparticles uptake by Vitis vinifera and grapevine-pathogenic fungi

Energy Technology Data Exchange (ETDEWEB)

Valletta, Alessio [“Sapienza” University of Rome, Department of Environmental Biology (Italy); Chronopoulou, Laura; Palocci, Cleofe, E-mail: cleofe.palocci@uniroma1.it [“Sapienza” University of Rome, Department of Chemistry (Italy); Baldan, Barbara [University of Padua, Department of Biology (Italy); Donati, Livia; Pasqua, Gabriella [“Sapienza” University of Rome, Department of Environmental Biology (Italy)

2014-12-15

Poly(lactic-co-glycolic) acid (PLGA)-based NPs are currently considered among the most promising drug carriers, nevertheless their use in plants has never been investigated. In this work, for the first time, we demonstrated the ability of PLGA NPs to cross the plant cell wall and membrane of Vitis vinifera cell cultures and grapevine-pathogenic fungi. By means of fluorescence microscopy, we established that PLGA NPs can enter in grapevine leaf tissues through stomata openings and that they can be absorbed by the roots and transported to the shoot through vascular tissues. TEM analysis on cultured cells showed that NPs ≤ 50 nm could enter cells, while bigger ones remained attached to the cell wall. Viability tests demonstrated that PLGA NPs were not cytotoxic for V. vinifera-cultured cells. The cellular uptake of PLGA NPs by some important grapevine-pathogenic fungi has also been observed, thus suggesting that PLGA NPs could be used to deliver antifungal compounds within fungal cells. Overall the results reported suggest that such NPs may play a key role in future developments of agrobiotechnologies, as it is currently happening in biomedicine.

ANTIOXIDANT AND ANTIFUNGAL ACTIVITY OF SELECTED MEDICINAL PLANT EXTRACTS AGAINST PHYTOPATHOGENIC FUNGI.

Science.gov (United States)

Mahlo, Salome Mamokone; Chauke, Hasani Richard; McGaw, Lyndy; Eloff, Jacobus

2016-01-01

Medicinal plants are used by many ethnic groups as a source of medicine for the treatment of various ailments in both humans and domestic animals. These plants produce secondary metabolites that have antimicrobial properties, thus screening of medicinal plants provide another alternative for producing chemical fungicides that are relatively non-toxic and cost-effective. Leaf extracts of selected South African plant species ( Bucida buceras, Breonadia salicina, Harpephyllum caffrum, Olinia ventosa, Vangueria infausta and Xylotheca kraussiana ) were investigated for activity against selected phytopathogenic fungi ( Aspergillus niger, Aspergillus parasiticus, Colletotricum gloeosporioides, Penicillium janthinellum, P. expansum, Trichoderma harzianum and Fusarium oxysporum ). These plant fungal pathogens causes major economic losses in fruit industry such as blue rot on nectaries and postharvest disease in citrus. Plant species were selected from 600 evaluated inter alia, against two animal fungal pathogens ( Candida albicans and Cryptococcus neoformans ). Antioxidant activity of the selected plant extracts were investigated using a qualitative assay (2, 2-diphenyl-1-picrylhydrazyl (DPPH)). Bioautography assay was used to determine the number of antifungal compounds in plant extracts. All plant extracts were active against the selected plant phytopathogenic fungi. Moreover, Bucida buceras had the best antifungal activity against four of the fungi, with minimum inhibitory concentration (MIC) values as low as 0.02 mg/ml and 0.08 mg/ml against P. expansum, P. janthinellum, T. harzianum and F. oxysporum . The plant extracts of five plant species did not possess strong antioxidant activity. However, methanol extract of X. kraussiana was the most active radical scavenger in the DPPH assay amongst the six medicinal plants screened. No antifungal compounds were observed in some of the plant extracts with good antifungal activity as shown in the microdilution assay, indicating

Flavonoids and Strigolactones in Root Exudates as Signals in Symbiotic and Pathogenic Plant-Fungus Interactions

Directory of Open Access Journals (Sweden)

Horst Vierheilig

2007-07-01

Full Text Available Secondary plant compounds are important signals in several symbiotic and pathogenic plant-microbe interactions. The present review is limited to two groups of secondary plant compounds, flavonoids and strigolactones, which have been reported in root exudates. Data on flavonoids as signaling compounds are available from several symbiotic and pathogenic plant-microbe interactions, whereas only recently initial data on the role of strigolactones as plant signals in the arbuscular mycorrhizal symbiosis have been reported. Data from other plant-microbe interactions and strigolactones are not available yet. In the present article we are focusing on flavonoids in plant-fungalinteractions such as the arbuscular mycorrhizal (AM association and the signaling between different Fusarium species and plants. Moreover the role of strigolactones in the AM association is discussed and new data on the effect of strigolactones on fungi, apart from arbuscular mycorrhizal fungi (AMF, are provided.

Adult trees cause density-dependent mortality in conspecific seedlings by regulating the frequency of pathogenic soil fungi.

Science.gov (United States)

Liang, Minxia; Liu, Xubing; Gilbert, Gregory S; Zheng, Yi; Luo, Shan; Huang, Fengmin; Yu, Shixiao

2016-12-01

Negative density-dependent seedling mortality has been widely detected in tropical, subtropical and temperate forests, with soil pathogens as a major driver. Here we investigated how host density affects the composition of soil pathogen communities and consequently influences the strength of plant-soil feedbacks. In field censuses of six 1-ha permanent plots, we found that survival was much lower for newly germinated seedlings that were surrounded by more conspecific adults. The relative abundance of pathogenic fungi in soil increased with increasing conspecific tree density for five of nine tree species; more soil pathogens accumulated around roots where adult tree density was higher, and this greater pathogen frequency was associated with lower seedling survival. Our findings show how tree density influences populations of soil pathogens, which creates plant-soil feedbacks that contribute to community-level and population-level compensatory trends in seedling survival. © 2016 John Wiley & Sons Ltd/CNRS.

Ecological niche of plant pathogens

Directory of Open Access Journals (Sweden)

Ecaterina Fodor

2011-06-01

Full Text Available Disease ecology is a new approach to the understanding of the spread and dynamics of pathogens in natural and man-made environments. Defining and describing the ecological niche of the pathogens is one of the major tasks for ecological theory, as well as for practitioners preoccupied with the control and forecasting of established and emerging diseases. Niche theory has been periodically revised, not including in an explicit way the pathogens. However, many progresses have been achieved in niche modeling of disease spread, but few attempts were made to construct a theoretical frame for the ecological niche of pathogens. The paper is a review of the knowledge accumulated during last decades in the niche theory of pathogens and proposes an ecological approach in research. It quest for new control methods in what concerns forest plant pathogens, with a special emphasis on fungi like organisms of the genus Phytophthora. Species of Phytophthora are the most successful plant pathogens of the moment, affecting forest and agricultural systems worldwide, many of them being invasive alien organisms in many ecosystems. The hyperspace of their ecological niche is defined by hosts, environment and human interference, as main axes. To select most important variables within the hyperspace, is important the understanding of the complex role of pathogens in the ecosystems as well as for control programs. Biotic relationships within ecosystem of host-pathogen couple are depicted by ecological network and specific metrics attached to this. The star shaped network is characterized by few high degree nodes, by short path lengths and relatively low connectivity, premises for a rapid disturbance spread. 

Ecological niche of plant pathogens

Directory of Open Access Journals (Sweden)

Ecaterina Fodor

2011-02-01

Full Text Available Disease ecology is a new approach to the understanding of the spread and dynamics of pathogens in natural and man-made environments. Defining and describing the ecological niche of the pathogens is one of the major tasks for ecological theory, as well as for practitioners preoccupied with the control and forecasting of established and emerging diseases. Niche theory has been periodically revised, not including in an explicit way the pathogens. However, many progresses have been achieved in niche modeling of disease spread, but few attempts were made to construct a theoretical frame for the ecological niche of pathogens. The paper is a review of the knowledge accumulated during last decades in the niche theory of pathogens and proposes an ecological approach in research. It quest for new control methods in what concerns forest plant pathogens, with a special emphasis on fungi like organisms of the genus Phytophthora. Species of Phytophthora are the most successful plant pathogens of the moment, affecting forest and agricultural systems worldwide, many of them being invasive alien organisms in many ecosystems. The hyperspace of their ecological niche is defined by hosts, environment and human interference, as main axes. To select most important variables within the hyperspace, is important for the understanding of the complex role of pathogens in the ecosystems as well as for control programs. Biotic relationships within ecosystem of host-pathogen couple are depicted by ecological network and specific metrics attached to this. The star shaped network is characterized by few high degree nodes, by short path lengths and relatively low connectivity, premises for a rapid disturbance spread.

A field study using the fungicide benomyl to investigate the effect of mycorrhizal fungi on plant fitness.

Science.gov (United States)

Carey, Peter D; Fitter, Alastair H; Watkinson, Andrew R

1992-07-01

The effect of vesicular-arbuscular mycorrhiza (VAM) on the fecundity ofVulpia ciliata ssp.ambigua was investigated at two field sites in eastern England by applying the fungicide benomyl to reduce VAM infection. The application of benomyl at the two sites produced very different results. At one site the application of the fungicide reduced the fecundity of plants whereas at the other fecundity was increased. At the first site the reduction in fecundity was linked to a significant reduction in VAM infection on the sprayed plants. The mechanism of the benefit associated with the VAM infection is however unclear: there was no treatment effect on morphology or on phosphorus inflow. At the second site, where fecundity was increased, there was only a negligible amount of VAM infection amongst the unsprayed plants and it is suggested that the increase in fecundity with the application of benomyl may have resulted from a reduction in infection by other, presumably pathogenic, fungi. The value of VAM fungi to the host plant may therefore not be restricted to physiological benefits. They may also provide protection to the plant by competing for space with other species of pathogenic fungi.

[Isolation of endophytic fungi from medicinal plant Brucea javanica and their microbial inhibition activity].

Science.gov (United States)

Liang, Zi-Ning; Zhu, Hua; Lai, Kai-Ping; Chen, Long

2014-04-01

To isolate and identify endophytic fungi from Brucea javanica, and to detect the antimicrobial activity of these strains. Endophytic fungi were isolated by tissue inoculation culture and identified by conventional morphological characteristic method. Seven kinds of pathogenic fungi and three kinds of bacteria were used as targeting microbes to test microbial inhibition activities by agar plate antagonistic action and modified agar gel diffusion methods, respectively. A total of 83 endophytic fungi strains were isolated from the root, stem, leaf and fruit of Brucea javanica. 34 strains were obtained from the stem, 32 strains were obtained from the leaf, 15 strains were isolated from the root and 2 strains came from the fruit. These 73 strains which had been identified attribute to 5 orders, 6 families and 12 genera. For the isolated strains, 14 strains had antifungal activities against at least one pathogenic fungi, 9 strains showed antibacterial activities against one or more bacteria. Especially, the strain YJ-17 which belonged to Phomopsis genus showed the best inhibitory effect on the targeting microbes. The endophytic fungi from Brucea javanica show diversity and microbial inhibition activity, and are worthy for further study on plant disease controlling.

Identification of a new biocontrol gene in Trichoderma atroviride: the role of an ABC transporter membrane pump in the interaction with different plant-pathogenic fungi.

Science.gov (United States)

Ruocco, Michelina; Lanzuise, Stefania; Vinale, Francesco; Marra, Roberta; Turrà, David; Woo, Sheridan Lois; Lorito, Matteo

2009-03-01

Successful biocontrol interactions often require that the beneficial microbes involved are resistant or tolerant to a variety of toxicants, including antibiotics produced by themselves or phytopathogens, plant antimicrobial compounds, and synthetic chemicals or contaminants. The ability of Trichoderma spp., the most widely applied biocontrol fungi, to withstand different chemical stresses, including those associated with mycoparasitism, is well known. In this work, we identified an ATP-binding cassette transporter cell membrane pump as an important component of the above indicated resistance mechanisms that appears to be supported by an extensive and powerful cell detoxification system. The encoding gene, named Taabc2, was cloned from a strain of Trichoderma atroviride and characterized. Its expression was found to be upregulated in the presence of pathogen-secreted metabolites, specific mycotoxins and some fungicides, and in conditions that stimulate the production in Trichoderma spp. of antagonism-related factors (toxins and enzymes). The key role of this gene in antagonism and biocontrol was demonstrated by the characterization of the obtained deletion mutants. They suffered an increased susceptibility to inhibitory compounds either secreted by pathogenic fungi or possibly produced by the biocontrol microbe itself and lost, partially or entirely, the ability to protect tomato plants from Pythium ultimum and Rhizoctonia solani attack.

The role of strigolactones during plant interactions with the pathogenic fungus Fusarium oxysporum.

Science.gov (United States)

Foo, Eloise; Blake, Sara N; Fisher, Brendan J; Smith, Jason A; Reid, James B

2016-06-01

Strigolactones (SLs) do not influence spore germination or hyphal growth of Fusarium oxysporum. Mutant studies revealed no role for SLs but a role for ethylene signalling in defence against this pathogen in pea. Strigolactones (SLs) play important roles both inside the plant as a hormone and outside the plant as a rhizosphere signal in interactions with mycorrhizal fungi and parasitic weeds. What is less well understood is any potential role SLs may play in interactions with disease causing microbes such as pathogenic fungi. In this paper we investigate the influence of SLs on the hemibiotrophic pathogen Fusarium oxysporum f.sp. pisi both directly via their effects on fungal growth and inside the plant through the use of a mutant deficient in SL. Given that various stereoisomers of synthetic and naturally occuring SLs can display different biological activities, we used (+)-GR24, (-)-GR24 and the naturally occurring SL, (+)-strigol, as well as a racemic mixture of 5-deoxystrigol. As a positive control, we examined the influence of a plant mutant with altered ethylene signalling, ein2, on disease development. We found no evidence that SLs influence spore germination or hyphal growth of Fusarium oxysporum and that, while ethylene signalling influences pea susceptibility to this pathogen, SLs do not.

Genome-Enhanced Detection and Identification (GEDI of plant pathogens

Directory of Open Access Journals (Sweden)

Nicolas Feau

2018-02-01

Full Text Available Plant diseases caused by fungi and Oomycetes represent worldwide threats to crops and forest ecosystems. Effective prevention and appropriate management of emerging diseases rely on rapid detection and identification of the causal pathogens. The increase in genomic resources makes it possible to generate novel genome-enhanced DNA detection assays that can exploit whole genomes to discover candidate genes for pathogen detection. A pipeline was developed to identify genome regions that discriminate taxa or groups of taxa and can be converted into PCR assays. The modular pipeline is comprised of four components: (1 selection and genome sequencing of phylogenetically related taxa, (2 identification of clusters of orthologous genes, (3 elimination of false positives by filtering, and (4 assay design. This pipeline was applied to some of the most important plant pathogens across three broad taxonomic groups: Phytophthoras (Stramenopiles, Oomycota, Dothideomycetes (Fungi, Ascomycota and Pucciniales (Fungi, Basidiomycota. Comparison of 73 fungal and Oomycete genomes led the discovery of 5,939 gene clusters that were unique to the targeted taxa and an additional 535 that were common at higher taxonomic levels. Approximately 28% of the 299 tested were converted into qPCR assays that met our set of specificity criteria. This work demonstrates that a genome-wide approach can efficiently identify multiple taxon-specific genome regions that can be converted into highly specific PCR assays. The possibility to easily obtain multiple alternative regions to design highly specific qPCR assays should be of great help in tackling challenging cases for which higher taxon-resolution is needed.

A comparative genome analysis of Cercospora sojina with other members of the pathogen genus Mycosphaerella on different plant hosts

Directory of Open Access Journals (Sweden)

Fanchang Zeng

2017-09-01

Full Text Available Fungi are the causal agents of many of the world's most serious plant diseases causing disastrous consequences for large-scale agricultural production. Pathogenicity genomic basis is complex in fungi as multicellular eukaryotic pathogens. Here, we report the genome sequence of C. sojina, and comparative genome analysis with plant pathogen members of the genus Mycosphaerella (Zymoseptoria. tritici (synonyms M. graminicola, M. pini, M. populorum and M. fijiensis - pathogens of wheat, pine, poplar and banana, respectively. Synteny or collinearity was limited between genomes of major Mycosphaerella pathogens. Comparative analysis with these related pathogen genomes indicated distinct genome-wide repeat organization features. It suggests repetitive elements might be responsible for considerable evolutionary genomic changes. These results reveal the background of genomic differences and similarities between Dothideomycete species. Wide diversity as well as conservation on genome features forms the potential genomic basis of the pathogen specialization, such as pathogenicity to woody vs. herbaceous hosts. Through comparative genome analysis among five Dothideomycete species, our results have shed light on the genome features of these related fungi species. It provides insight for understanding the genomic basis of fungal pathogenicity and disease resistance in the crop hosts.

The Plant Ribosome-Inactivating Proteins Play Important Roles in Defense against Pathogens and Insect Pest Attacks

Directory of Open Access Journals (Sweden)

Feng Zhu

2018-02-01

Full Text Available Ribosome-inactivating proteins (RIPs are toxic N-glycosidases that depurinate eukaryotic and prokaryotic rRNAs, thereby arresting protein synthesis during translation. RIPs are widely found in various plant species and within different tissues. It is demonstrated in vitro and in transgenic plants that RIPs have been connected to defense by antifungal, antibacterial, antiviral, and insecticidal activities. However, the mechanism of these effects is still not completely clear. There are a number of reviews of RIPs. However, there are no reviews on the biological functions of RIPs in defense against pathogens and insect pests. Therefore, in this report, we focused on the effect of RIPs from plants in defense against pathogens and insect pest attacks. First, we summarize the three different types of RIPs based on their physical properties. RIPs are generally distributed in plants. Then, we discuss the distribution of RIPs that are found in various plant species and in fungi, bacteria, algae, and animals. Various RIPs have shown unique bioactive properties including antibacterial, antifungal, antiviral, and insecticidal activity. Finally, we divided the discussion into the biological roles of RIPs in defense against bacteria, fungi, viruses, and insects. This review is focused on the role of plant RIPs in defense against bacteria, fungi, viruses, and insect attacks. The role of plant RIPs in defense against pathogens and insects is being comprehended currently. Future study utilizing transgenic technology approaches to study the mechanisms of RIPs will undoubtedly generate a better comprehending of the role of plant RIPs in defense against pathogens and insects. Discovering additional crosstalk mechanisms between RIPs and phytohormones or reactive oxygen species (ROS against pathogen and insect infections will be a significant subject in the field of biotic stress study. These studies are helpful in revealing significance of genetic control that can

Rapid identification and detection of pathogenic Fungi by padlock probes

NARCIS (Netherlands)

Tsui, C.K.M.; Wang, B.; Schoen, C.D.; Hamelin, R.C.

2013-01-01

Fungi are important pathogens of human diseases, as well as to agricultural crop and trees. Molecular diagnostics can detect diseases early, and improve identification accuracy and follow-up disease management. The use of padlock probe is effective to facilitate these detections and pathogen

A review on the inhibitory potential of Nigella sativa against pathogenic and toxigenic fungi.

Science.gov (United States)

Shokri, Hojjatollah

2016-01-01

Nigella sativa (N. sativa) grows in various parts of the world, particularly in Iran. It has been traditionally used as a folk remedy to treat a number of diseases. The seeds of this plant contain moisture, proteins, carbohydrates, crude fiber, alkaloids, saponins, ash, fixed oils and essential oil. The major components of the essential oil are thymoquinone, p-cymene, trans-anethole, 2-methyl-5(1-methyl ethyl)-Bicyclo[3.1.0]hex-2-en and γ-terpinene. So far, several pharmacological effects such as anti-oxidant, anti-inflammatory, anti-cancer and anti-microbial have been reported for N. sativa or its active compounds. Thymoquinone, thymohydroquinone and thymol are the most active constituents which have different beneficial properties. The oil, extracts and some of N. sativa active components possessed moderate in vitro and in vivo inhibitory activity against pathogenic yeasts, dermatophytes, non-dermatophytic filamentous fungi and aflatoxin-producing fungi. The main morphological changes of pathogenic and toxigenic fungi treated with N. sativa oil were observed in the cell wall, plasma membrane and membranous organelles, particularly in the nuclei and mitochondria. Although this review represents first step in the search for a new anti-fungal drug, the full potential of N. sativa as a fungitoxic agent has not been exploited and necessitates further investigations.

Seedborne Pathogenic Fungi in Common Bean (Phaseolus vulgaris cv. INTA Rojo) in Nicaragua.

Science.gov (United States)

Marcenaro, Delfia; Valkonen, Jari P T

2016-01-01

Common bean (Phaseolus vulgaris L.) is an important legume with high nutritional value. In Nicaragua, certified healthy seeds of local bean varieties are not available, and seedborne fungi have gained little attention. Here, were surveyed seedborne pathogenic fungi in an important local bean cultivar, 'INTA Rojo'. Beans grown in the four main production areas in Nicaragua (Boaco, Carazo, Estelí, Matagalpa) for future use as seed stock were sampled from four seed storehouses and six seed lots. A total of 133 fungal strains were isolated from surface-sterilized beans and inoculated to healthy lima beans (Phaseolus lunatus) under controlled conditions. Eighty-seven isolates caused symptoms of varying severity in the seedlings, including discoloration, necrotic lesions, cankers, rot, and lethal necrosis. Pathogenic isolates were divided into eight phenotypically distinguishable groups based on morphology and growth characteristics on artificial growth medium, and further identified by analysis of the internal transcribed spacer sequences (ITS1 and ITS2) of the ribosomal RNA genes. The pathogenic isolates belonged to eight genera. Fusarium spp. (F. chlamydosporum, F. equiseti, F. incarnatum), Lasiodiplodia theobromae, Macrophomina phaseolina, and Penicillium citrinum were the most damaging and common fungi found in the seed lots. Furthermore, Corynespora cassiicola, Colletotrichum capsisi, Colletotrichum gloeosporioides, Aspergillus flavus, and Diaporthe sp. (Phomopsis) were seedborne in cultivar 'INTA Rojo' and found to be pathogenic to bean seedlings. This study reveals, for the first time, many seedborne pathogenic fungi in beans in Nicaragua; furthermore, prior to this study, little information was available concerning F. equiseti, F. incarnatum, L. theobromae, C. cassiicola, and Diaporthe spp. as seedborne pathogens of common bean. Our results lay the basis for developing diagnostic tools for seed health inspection and for further study of the epidemiology

Communication between filamentous pathogens and plants at the biotrophic interface.

Science.gov (United States)

Yi, Mihwa; Valent, Barbara

2013-01-01

Fungi and oomycetes that colonize living plant tissue form extensive interfaces with plant cells in which the cytoplasm of the microorganism is closely aligned with the host cytoplasm for an extended distance. In all cases, specialized biotrophic hyphae function to hijack host cellular processes across an interfacial zone consisting of a hyphal plasma membrane, a specialized interfacial matrix, and a plant-derived membrane. The interface is the site of active secretion by both players. This cross talk at the interface determines the winner in adversarial relationships and establishes the partnership in mutualistic relationships. Fungi and oomycetes secrete many specialized effector proteins for controlling the host, and they can stimulate remarkable cellular reorganization even in distant plant cells. Breakthroughs in live-cell imaging of fungal and oomycete encounter sites, including live-cell imaging of pathogens secreting fluorescently labeled effector proteins, have led to recent progress in understanding communication across the interface.

Molecular phylogeny, diversity and bioprospecting of endophytic fungi associated with wild ethnomedicinal North American plant Echinacea purpurea (Asteraceae)

Science.gov (United States)

The endophytic fungal community associated with the wild ethnomedicinal North American plant Echinacea purpurea was investigated as well as its potential for providing antifungal compounds against plant pathogenic fungi. A total of 233 endophytic fungal isolates were obtained and classified into 42 ...

Arbuscular mycorrhizal fungi counteract the Janzen-Connell effect of soil pathogens

NARCIS (Netherlands)

Liang, Minxia; Liu, Xubing; Etienne, Rampal S; Huang, Fengmin; Wang, Yongfan; Yu, Shixiao

Soilborne pathogens can contribute to diversity maintenance in tree communities through the Janzen-Connell effect, whereby the pathogenic reduction of seedling performance attenuates with distance from conspecifics. By contrast, arbuscular mycorrhizal fungi (AMF) have been reported to promote

Peptide-Like Nylon-3 Polymers with Activity against Phylogenetically Diverse, Intrinsically Drug-Resistant Pathogenic Fungi.

Science.gov (United States)

Rank, Leslie A; Walsh, Naomi M; Lim, Fang Yun; Gellman, Samuel H; Keller, Nancy P; Hull, Christina M

2018-01-01

Understanding the dimensions of fungal diversity has major implications for the control of diseases in humans, plants, and animals and in the overall health of ecosystems on the planet. One ancient evolutionary strategy organisms use to manage interactions with microbes, including fungi, is to produce host defense peptides (HDPs). HDPs and their synthetic analogs have been subjects of interest as potential therapeutic agents. Due to increases in fungal disease worldwide, there is great interest in developing novel antifungal agents. Here we describe activity of polymeric HDP analogs against fungi from 18 pathogenic genera composed of 41 species and 72 isolates. The synthetic polymers are members of the nylon-3 family (poly-β-amino acid materials). Three different nylon-3 polymers show high efficacy against surprisingly diverse fungi. Across the phylogenetic spectrum (with the exception of Aspergillus species), yeasts, dermatophytes, dimorphic fungi, and molds were all sensitive to the effects of these polymers. Even fungi intrinsically resistant to current antifungal drugs, such as the causative agents of mucormycosis ( Rhizopus spp.) and those with acquired resistance to azole drugs, showed nylon-3 polymer sensitivity. In addition, the emerging pathogens Pseudogymnoascus destructans (cause of white nose syndrome in bats) and Candida auris (cause of nosocomial infections of humans) were also sensitive. The three nylon-3 polymers exhibited relatively low toxicity toward mammalian cells. These findings raise the possibility that nylon-3 polymers could be useful against fungi for which there are only limited and/or no antifungal agents available at present. IMPORTANCE Fungi reside in all ecosystems on earth and impart both positive and negative effects on human, plant, and animal health. Fungal disease is on the rise worldwide, and there is a critical need for more effective and less toxic antifungal agents. Nylon-3 polymers are short, sequence random, poly

Importance of seed-borne fungi of sorghum and pearl millet in Burkina Faso and their control using plant extracts.

Science.gov (United States)

Zida, Pawindé Elisabeth; Sérémé, Paco; Leth, Vibeke; Sankara, Philippe; Somda, Irénée; Néya, Adama

2008-02-01

Seed-borne fungi of sorghum and pearl millet in Burkina Faso were surveyed. A total of 188 seed samples from various locations, collected in 1989 (42) and 2002 (146), were tested, using the blotter, dry inspection and washing methods. Infection experiments were carried out with the major fungi recorded on each crop by the blotter test. Six essential oils of plants were investigated for their inhibitory activity against eight pathogenic fungi. Thirty four and 27 fungal species were found in seed samples of sorghum and pearl millet, respectively. Phoma sp. and Fusarium moniliforme infected 95 to 100% of the seed samples of both sorghum and pearl millet. Sphacelotheca sorghi and Tolyposporium ehrenbergii were encountered in respectively, 75 and 33% of seed samples of sorghum. T. penicillariae, Sclerospora graminicola and Claviceps fusiformis were present in 88, 41 and 32% of seed samples of pearl millet, respectively. Seeds inoculated with Acremonium strictum, Curvularia oryzae, F. equiseti, F. moniliforme and F. subglutinans and sown in sterilized soil, showed considerable mortality of the seedlings. Three essential oils inhibited in vitro the mycelial growth of all the fungi used by 85 to 100% and reduced significantly sorghum and pearl millet seed infection rates of Phoma sp., Fusarium sp., Curvularia sp., Colletotrichum graminicola and Exserohilum sp. Presence of many pathogenic fungi in considerable number of seed samples indicates the need of field surveys for these and other pathogens. Development of plant extracts for the control of seed-borne pathogens and public awareness on seed-borne diseases management measures for maintaining quality seed should be increased.

Paleogene radiation of a plant pathogenic mushroom.

Directory of Open Access Journals (Sweden)

Martin P A Coetzee

Full Text Available The global movement and speciation of fungal plant pathogens is important, especially because of the economic losses they cause and the ease with which they are able to spread across large areas. Understanding the biogeography and origin of these plant pathogens can provide insights regarding their dispersal and current day distribution. We tested the hypothesis of a Gondwanan origin of the plant pathogenic mushroom genus Armillaria and the currently accepted premise that vicariance accounts for the extant distribution of the species.The phylogeny of a selection of Armillaria species was reconstructed based on Maximum Parsimony (MP, Maximum Likelihood (ML and Bayesian Inference (BI. A timeline was then placed on the divergence of lineages using a Bayesian relaxed molecular clock approach.Phylogenetic analyses of sequenced data for three combined nuclear regions provided strong support for three major geographically defined clades: Holarctic, South American-Australasian and African. Molecular dating placed the initial radiation of the genus at 54 million years ago within the Early Paleogene, postdating the tectonic break-up of Gondwana.The distribution of extant Armillaria species is the result of ancient long-distance dispersal rather than vicariance due to continental drift. As these finding are contrary to most prior vicariance hypotheses for fungi, our results highlight the important role of long-distance dispersal in the radiation of fungal pathogens from the Southern Hemisphere.

Comparative Genomics Yields Insights into Niche Adaptation of Plant Vascular Wilt Pathogens

NARCIS (Netherlands)

Klosterman, S.J.; Subbarao, K.V.; Kang, S.; Veronese, P.; Gold, S.E.; Thomma, B.P.H.J.; Chen, Z.J.; Henrissat, B.; Lee, Y.H.; Park, J.; Garcia-Pedrajas, M.D.; Barbara, D.J.; Anchieta, A.; Jonge, de R.; Santhanam, P.; Maruthachalam, K.; Atallah, Z.; Amyotte, S.G.; Paz, Z.; Inderbitzin, P.; Hayes, R.J.; Heiman, D.I.; Young, S.; Zeng, Q.; Engels, R.; Galagan, J.; Cuomo, C.; Dobinson, K.F.; Ma, L.J.

2011-01-01

The vascular wilt fungi Verticillium dahliae and V. albo-atrum infect over 200 plant species, causing billions of dollars in annual crop losses. The characteristic wilt symptoms are a result of colonization and proliferation of the pathogens in the xylem vessels, which undergo fluctuations in

The ascomycete Verticillium longisporum is a hybrid and a plant pathogen with an expanded host range.

Directory of Open Access Journals (Sweden)

Patrik Inderbitzin

Full Text Available Hybridization plays a central role in plant evolution, but its overall importance in fungi is unknown. New plant pathogens are thought to arise by hybridization between formerly separated fungal species. Evolution of hybrid plant pathogens from non-pathogenic ancestors in the fungal-like protist Phytophthora has been demonstrated, but in fungi, the most important group of plant pathogens, there are few well-characterized examples of hybrids. We focused our attention on the hybrid and plant pathogen Verticillium longisporum, the causal agent of the Verticillium wilt disease in crucifer crops. In order to address questions related to the evolutionary origin of V. longisporum, we used phylogenetic analyses of seven nuclear loci and a dataset of 203 isolates of V. longisporum, V. dahliae and related species. We confirmed that V. longisporum was diploid, and originated three different times, involving four different lineages and three different parental species. All hybrids shared a common parent, species A1, that hybridized respectively with species D1, V. dahliae lineage D2 and V. dahliae lineage D3, to give rise to three different lineages of V. longisporum. Species A1 and species D1 constituted as yet unknown taxa. Verticillium longisporum likely originated recently, as each V. longisporum lineage was genetically homogenous, and comprised species A1 alleles that were identical across lineages.

Secondary metabolites of Antarctic fungi antagonistic to aquatic pathogenic bacteria

Directory of Open Access Journals (Sweden)

Zhao Huibin

2018-03-01

Full Text Available Polar microbial derived antibiotics have potential as alternatives to traditional antibiotics in treating fish against pathogenic bacteria. In this paper, 23 strains of polar fungi were fermented to detect bacteriostatic products on three aquatic pathogenic bacteria, subsequently the active fungus was identified. It was indicated that secondary metabolites of 23 strains weredistinct; of these, the extract of strain B-7 (belonging to Bjerkandera according to molecular identification demonstrated a strong antibacterial activity to Streptococcus agalactiae, Vibrio anguillarum and Aeromonas hydrophila ATCC7966 by Kirby-Bauerpaper strip method. During one fermentation cycle, the pH curve of the fermentation liquor became lowest (4.0 on the 4th day and rose back to 7.6 finally after 5 days, The residual sugar curve was decreased before stablising on the 6th day. It is presumed that a large amount of alkaline secondary metabolites might have been produced during fermentation. This study focuses on antagonism between aquatic pathogenic bacteria and fermentation metabolites from Antarctic fungi for the first time, which may provide data on research of antibiotics against aquatic pathogenic bacteria.

Melanin as a virulence factor of Paracoccidioides brasiliensis and other dimorphic pathogenic fungi: a minireview

OpenAIRE

Taborda, Carlos P.; da Silva, Marcelo B.; Nosanchuk, Joshua D.; Travassos, Luiz R.

2008-01-01

Melanin pigments are substances produced by a broad variety of pathogenic microorganisms, including bacteria, fungi, and helminths. Microbes predominantly produce melanin pigment via tyrosinases, laccases, catecholases, and the polyketide synthase pathway. In fungi, melanin is deposited in the cell wall and cytoplasm, and melanin particles (“ghosts”) can be isolated from these fungi that have the same size and shape of the original cells. Melanin has been reported in several human pathogenic ...

Toxicity of Lanthanum to Pathogenic Fungi and Its Morphological Characteristics

Institute of Scientific and Technical Information of China (English)

无

2006-01-01

The inhibitory effects of La on the mycelial growth of several soil-borne pathogenic fungi including Rhizoctonia solani , Pythium sp . , Fusarium solani , Selerotinia sclerotiorum , and Fusarium oxyspoxum were studied in vitro. The results show that the mycelial growth was inhibited strongly by the La, with EC50 of 130 ～ 320 mg· L-1 and EC95 of about 550 ～ 40007 mg· L- 1 respectively. In addition, the morphological toxicity of La was studied by using the scanning electronic microscope. Treated by La, the mycelial growth of pathogenic fungi was significantly restrained, and the morphological characteristics were found to be abnormal, such as increased ramification, malformation, partial swelling and shrinking, and irregularly entangled mycelial block or rhizomorph.

Evaluation of pathogenic fungi occurrence in traumatogenic structures of freshwater fish

Directory of Open Access Journals (Sweden)

Fabio Caetano Oliveira Leme

2011-04-01

Full Text Available INTRODUCTION: Fungal infections in human skin, such as sporotrichosis, can occur after fish induced trauma. This work aimed to identify fungi in freshwater fish that are pathogenic to humans. METHODS: Extraction of dental arches from Serrassalmus maculatus (piranha and Hoplias malabaricus (wolf fish, stings from Pimelodus maculatus (mandis catfish, dorsal fin rays from Plagioscion spp. (corvina and Tilapia spp., for culture in Mycosel agar. Some cultures were submitted to DNA extraction for molecular identification by sequencing ITS-5.8S rDNA. RESULTS: Cultures identified most yeast as Candida spp., while sequencing also permitted the identification of Phoma spp. and Yarrowia lipolytica. CONCLUSIONS: While the search for S. schenckii was negative, the presence of fungus of the genera Phoma and Candida revealed the pathogenic potential of this infection route. The genus Phoma is involved in certain forms of phaeohyphomycosis, a subcutaneous mycosis caused by dematiaceous fungi, with reports of infections in human organs and systems. Traumatizing structures of some freshwater fish present pathogenic fungi and this may be an important infection route that must be considered in some regions of Brazil, since there are a large number of a fisherman in constant contact with traumatogenic fish.

Antifungal potential of marine sponge extract against plant and fish pathogenic fungi

Digital Repository Service at National Institute of Oceanography (India)

PrabhaDevi; Ravichandran, S.; Ribeiro, M.; Ciavatta, M.L.

scope for rediscovering compounds with antimicrobial activity. This study screens extracts (Diethyl Ether and Butanol) of a marine red-Sea sponge Negombata magnifica for invitro fungicidal activity against 10 plant and 3 fish pathogens. Fungicidal...

Isolation and identification of local bacteria endophyte and screening of its antimicrobial property against pathogenic bacteria and fungi

Science.gov (United States)

Fikri, Ahmad Syairazie Ibrahim; Rahman, Irman Abdul; Nor, Norefrina Shafinaz Md; Hamzah, Ainon

2018-04-01

Endophytes are organisms, often fungi and bacteria that live in living plant cells. These organisms reside in the living tissues of the host plant in a variety of relationships, ranging from symbiotic to slightly pathogenic. The endophytes may produce a plethora of substances that have potential to be used in modern medicine, agriculture and industry. The aims of this study are to isolate, identify and screening antimicrobial activity of bacterial endophytes. The endophytes were isolated using nutrient agar, incubated at 37°C for 48 hours. Identification of the isolates were done based on morphological characteristics, biochemical tests and 16S rDNA molecular analysis. Disk diffusion method was used to screen for antimicrobial activity of metabolites from endophytes against pathogenic bacteria. Screening for antifungal activity of selected endophytes was done using dual culture method againts pathogenic fungi followed by Kirby-Bauer method. Results showed endophytes designated as B2c and B7b have positive antimicrobial activity. The metabolites from isolate B2c showed antimicrobial activity against pathogenic bacteria methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus aureus and Staphylococcus epidermis, while isolate B7b have positive activities againts MRSA, S. aureus and Pseudomonas aeruginosa. Isolates B2c displayed antifungal activity against Fusarium oxysporum, Fusarium solani, Phytophthora palmivora and Colletotrichum gloeosporioides. Identification using biochemical tests and 16S rDNA sequences identified isolate B2c as Pseudomonas resinovorans with 97% homology and isolate B7b as Bacillus subtilis with 98% homology.

Parallels in amphibian and bat declines from pathogenic fungi.

Science.gov (United States)

Eskew, Evan A; Todd, Brian D

2013-03-01

Pathogenic fungi have substantial effects on global biodiversity, and 2 emerging pathogenic species-the chytridiomycete Batrachochytrium dendrobatidis, which causes chytridiomycosis in amphibians, and the ascomycete Geomyces destructans, which causes white-nose syndrome in hibernating bats-are implicated in the widespread decline of their vertebrate hosts. We synthesized current knowledge for chytridiomycosis and white-nose syndrome regarding disease emergence, environmental reservoirs, life history characteristics of the host, and host-pathogen interactions. We found striking similarities between these aspects of chytridiomycosis and white-nose syndrome, and the research that we review and propose should help guide management of future emerging fungal diseases.

Plant species distribution along environmental gradient: do belowground interactions with fungi matter?

Directory of Open Access Journals (Sweden)

Loïc ePellissier

2013-12-01

Full Text Available The distribution of plants along environmental gradients is constrained by abiotic and biotic factors. Cumulative evidence attests of the impact of abiotic factors on plant distributions, but only few studies discuss the role of belowground communities. Soil fungi, in particular, are thought to play an important role in how plant species assemble locally into communities. We first review existing evidence, and then test the effect of the number of soil fungal operational taxonomic units (OTUs on plant species distributions using a recently collected dataset of plant and metagenomic information on soil fungi in the Western Swiss Alps. Using species distribution models, we investigated whether the distribution of individual plant species is correlated to the number of OTUs of two important soil fungal classes known to interact with plants: the Glomeromycetes, that are obligatory symbionts of plants, and the Agaricomycetes, that may be facultative plant symbionts, pathogens, or wood decayers. We show that including the fungal richness information in the models of plant species distributions improves predictive accuracy. Number of fungal OTUs is especially correlated to the distribution of high elevation plant species. We suggest that high elevation soil show greater variation in fungal assemblages that may in turn impact plant turnover among communities. We finally discuss how to move beyond correlative analyses, through the design of field experiments manipulating plant and fungal communities along environmental gradients.

Ant-plants and fungi: a new threeway symbiosis.

Science.gov (United States)

Defossez, Emmanuel; Selosse, Marc-André; Dubois, Marie-Pierre; Mondolot, Laurence; Faccio, Antonella; Djieto-Lordon, Champlain; McKey, Doyle; Blatrix, Rumsaïs

2009-06-01

Symbioses between plants and fungi, fungi and ants, and ants and plants all play important roles in ecosystems. Symbioses involving all three partners appear to be rare. Here, we describe a novel tripartite symbiosis in which ants and a fungus inhabit domatia of an ant-plant, and present evidence that such interactions are widespread. We investigated 139 individuals of the African ant-plant Leonardoxa africana for occurrence of fungus. Behaviour of mutualist ants toward the fungus within domatia was observed using a video camera fitted with an endoscope. Fungi were identified by sequencing a fragment of their ribosomal DNA. Fungi were always present in domatia occupied by mutualist ants but never in domatia occupied by opportunistic or parasitic ants. Ants appear to favour the propagation, removal and maintenance of the fungus. Similar fungi were associated with other ant-plants in Cameroon. All belong to the ascomycete order Chaetothyriales; those from L. africana formed a monophyletic clade. These new plant-ant-fungus associations seem to be specific, as demonstrated within Leonardoxa and as suggested by fungal phyletic identities. Such tripartite associations are widespread in African ant-plants but have long been overlooked. Taking fungal partners into account will greatly enhance our understanding of symbiotic ant-plant mutualisms.

Identification of some human pathogenic fungi using four DNA ...

African Journals Online (AJOL)

Stocks from pathogenic fungi isolated from infected areas on different patients, around Lagos-Nigeria were analysed using molecular methods (DNA extraction, PCR-RFLP and DNA sequencing). Four DNA extraction protocols were employed in the identification of the fungal isolates. Sixteen different fungal isolates were ...

Comparative genomics and transcriptomics depict ericoid mycorrhizal fungi as versatile saprotrophs and plant mutualists.

Science.gov (United States)

Martino, Elena; Morin, Emmanuelle; Grelet, Gwen-Aëlle; Kuo, Alan; Kohler, Annegret; Daghino, Stefania; Barry, Kerrie W; Cichocki, Nicolas; Clum, Alicia; Dockter, Rhyan B; Hainaut, Matthieu; Kuo, Rita C; LaButti, Kurt; Lindahl, Björn D; Lindquist, Erika A; Lipzen, Anna; Khouja, Hassine-Radhouane; Magnuson, Jon; Murat, Claude; Ohm, Robin A; Singer, Steven W; Spatafora, Joseph W; Wang, Mei; Veneault-Fourrey, Claire; Henrissat, Bernard; Grigoriev, Igor V; Martin, Francis M; Perotto, Silvia

2018-02-01

Some soil fungi in the Leotiomycetes form ericoid mycorrhizal (ERM) symbioses with Ericaceae. In the harsh habitats in which they occur, ERM plant survival relies on nutrient mobilization from soil organic matter (SOM) by their fungal partners. The characterization of the fungal genetic machinery underpinning both the symbiotic lifestyle and SOM degradation is needed to understand ERM symbiosis functioning and evolution, and its impact on soil carbon (C) turnover. We sequenced the genomes of the ERM fungi Meliniomyces bicolor, M. variabilis, Oidiodendron maius and Rhizoscyphus ericae, and compared their gene repertoires with those of fungi with different lifestyles (ecto- and orchid mycorrhiza, endophytes, saprotrophs, pathogens). We also identified fungal transcripts induced in symbiosis. The ERM fungal gene contents for polysaccharide-degrading enzymes, lipases, proteases and enzymes involved in secondary metabolism are closer to those of saprotrophs and pathogens than to those of ectomycorrhizal symbionts. The fungal genes most highly upregulated in symbiosis are those coding for fungal and plant cell wall-degrading enzymes (CWDEs), lipases, proteases, transporters and mycorrhiza-induced small secreted proteins (MiSSPs). The ERM fungal gene repertoire reveals a capacity for a dual saprotrophic and biotrophic lifestyle. This may reflect an incomplete transition from saprotrophy to the mycorrhizal habit, or a versatile life strategy similar to fungal endophytes. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

Evolution of entomopathogenicity in fungi.

Science.gov (United States)

Humber, Richard A

2008-07-01

The recent completions of publications presenting the results of a comprehensive study on the fungal phylogeny and a new classification reflecting that phylogeny form a new basis to examine questions about the origins and evolutionary implications of such major habits among fungi as the use of living arthropods or other invertebrates as the main source of nutrients. Because entomopathogenicity appears to have arisen or, indeed, have lost multiple times in many independent lines of fungal evolution, some of the factors that might either define or enable entomopathogenicity are examined. The constant proximity of populations of potential new hosts seem to have been a factor encouraging the acquisition or loss of entomopathogenicity by a very diverse range of fungi, particularly when involving gregarious and immobile host populations of scales, aphids, and cicadas (all in Hemiptera). An underlying theme within the vast complex of pathogenic and parasitic ascomycetes in the Clavicipitaceae (Hypocreales) affecting plants and insects seems to be for interkingdom host-jumping by these fungi from plants to arthropods and then back to the plant or on to fungal hosts. Some genera of Entomophthorales suggest that the associations between fungal pathogens and their insect hosts appear to be shifting away from pathogenicity and towards nonlethal parasitism.

Wild Honey Inhibits Growth od Some Phytopathogenic Fungi in vitro

Directory of Open Access Journals (Sweden)

K.I. Al-Mughrabi

2003-12-01

Full Text Available Wild honey was diluted to 1000 ppm with sterile distilled water and tested in vitro for inhibition of the plant pathogenic fungi Fusarium oxysporum, Rhizoctonia solani, Alternaria solani, Stemphylium solani, Colletotrichum sp., and Phytophthora infestans. Wild honey was effective against all these fungi, particularly A. solani and P. infestans, the causal agents of early and late blight diseases respectively; also against R. solani and F. oxysporum, and to a less extent against S. solani and Colletotrichum sp. This is the first report on the inhibiting effect of wild honey against plant pathogenic fungi.

Regulation and diversity of plant polysaccharide utilisation in fungi

NARCIS (Netherlands)

Battaglia, E.

2011-01-01

Filamentous fungi obtain their nutrients by degrading dead or living plant material. Plant material consists of different cell wall and storage polysaccharides. Due to the complex structure and the variety of plant polysaccharides, filamentous fungi secrete a wide range of plant polysaccharide

A novel high-affinity sucrose transporter is required for virulence of the plant pathogen Ustilago maydis.

Directory of Open Access Journals (Sweden)

Ramon Wahl

2010-02-01

Full Text Available Plant pathogenic fungi cause massive yield losses and affect both quality and safety of food and feed produced from infected plants. The main objective of plant pathogenic fungi is to get access to the organic carbon sources of their carbon-autotrophic hosts. However, the chemical nature of the carbon source(s and the mode of uptake are largely unknown. Here, we present a novel, plasma membrane-localized sucrose transporter (Srt1 from the corn smut fungus Ustilago maydis and its characterization as a fungal virulence factor. Srt1 has an unusually high substrate affinity, is absolutely sucrose specific, and allows the direct utilization of sucrose at the plant/fungal interface without extracellular hydrolysis and, thus, without the production of extracellular monosaccharides known to elicit plant immune responses. srt1 is expressed exclusively during infection, and its deletion strongly reduces fungal virulence. This emphasizes the central role of this protein both for efficient carbon supply and for avoidance of apoplastic signals potentially recognized by the host.

Sandpits as a reservoir of potentially pathogenic fungi for children

Directory of Open Access Journals (Sweden)

Anna Wójcik

2016-09-01

Potentially pathogenic fungi are present in the sand taken from sandpits in Łódź. This fact poses a significant threat to child health and therefore proper maintenance and periodic checking of sandpits are of great importance.

The isolation and identification of pathogenic fungi from Tessaratoma papillosa Drury (Hemiptera: Tessaratomidae).

Science.gov (United States)

Meng, Xiang; Hu, Junjie; Ouyang, Gecheng

2017-01-01

Litchi stink-bug, Tessaratoma papillosa Drury (Hemiptera: Tessaratomidae), is one of the most widespread and destructive pest species on Litchi chinensis Sonn and Dimocarpus longan Lour in Southern China. Inappropriate use of chemical pesticides has resulted in serious environmental problems and food pollution. Generating an improved Integrated Pest Management (IPM) strategy for litchi stink-bug in orchard farming requires development of an effective biological control agent. Entomopathogenic fungi are regarded as a vital ecological factor in the suppression of pest populations under field conditions. With few effective fungi and pathogenic strains available to control litchi stink-bug, exploration of natural resources for promising entomopathogenic fungi is warranted. In this study, two pathogenic fungi were isolated from cadavers of adult T. papillosa . They were identified as Paecilomyces lilacinus and Beauveria bassiana by morphological identification and rDNA-ITS homogeneous analysis. Infection of T. papillosa with B. bassiana and P. lilacinus occurred initially from the antennae, metameres, and inter-segmental membranes. Biological tests showed that the two entomopathogenic fungi induced high mortality in 2 nd and 5 th instar nymphs of T. papillosa . B. bassiana was highly virulent on 2 nd instar nymphs of T. papillosa , with values for cadaver rate, LC 50 and LT 50 of 88.89%, 1.92 × 10 7  conidia/mL and 4.34 days respectively. This study provides two valuable entomopathogenic fungi from T. papillosa . This finding suggests that the highly virulent P. lilacinus and B. bassiana play an important role in the biocontrol of T. papillosa in China. These pathogenic fungi had no pollution or residue risk, and could provide an alternative option for IPM of litchi stink-bug.

The isolation and identification of pathogenic fungi from Tessaratoma papillosa Drury (Hemiptera: Tessaratomidae

Directory of Open Access Journals (Sweden)

Xiang Meng

2017-10-01

Full Text Available Background Litchi stink-bug, Tessaratoma papillosa Drury (Hemiptera: Tessaratomidae, is one of the most widespread and destructive pest species on Litchi chinensis Sonn and Dimocarpus longan Lour in Southern China. Inappropriate use of chemical pesticides has resulted in serious environmental problems and food pollution. Generating an improved Integrated Pest Management (IPM strategy for litchi stink-bug in orchard farming requires development of an effective biological control agent. Entomopathogenic fungi are regarded as a vital ecological factor in the suppression of pest populations under field conditions. With few effective fungi and pathogenic strains available to control litchi stink-bug, exploration of natural resources for promising entomopathogenic fungi is warranted. Methods & Results In this study, two pathogenic fungi were isolated from cadavers of adult T. papillosa. They were identified as Paecilomyces lilacinus and Beauveria bassiana by morphological identification and rDNA-ITS homogeneous analysis. Infection of T. papillosa with B. bassiana and P. lilacinus occurred initially from the antennae, metameres, and inter-segmental membranes. Biological tests showed that the two entomopathogenic fungi induced high mortality in 2nd and 5th instar nymphs of T. papillosa. B. bassiana was highly virulent on 2nd instar nymphs of T. papillosa, with values for cadaver rate, LC50 and LT50 of 88.89%, 1.92 × 107 conidia/mL and 4.34 days respectively. Discussion This study provides two valuable entomopathogenic fungi from T. papillosa. This finding suggests that the highly virulent P. lilacinus and B. bassiana play an important role in the biocontrol of T. papillosa in China. These pathogenic fungi had no pollution or residue risk, and could provide an alternative option for IPM of litchi stink-bug.

The sugarcane defense protein SUGARWIN2 causes cell death in Colletotrichum falcatum but not in non-pathogenic fungi.

Directory of Open Access Journals (Sweden)

Flávia P Franco

Full Text Available Plants respond to pathogens and insect attacks by inducing and accumulating a large set of defense-related proteins. Two homologues of a barley wound-inducible protein (BARWIN have been characterized in sugarcane, SUGARWIN1 and SUGARWIN2 (sugarcane wound-inducible proteins. Induction of SUGARWINs occurs in response to Diatraea saccharalis damage but not to pathogen infection. In addition, the protein itself does not show any effect on insect development; instead, it has antimicrobial activities toward Fusarium verticillioides, an opportunistic fungus that usually occurs after D. saccharalis borer attacks on sugarcane. In this study, we sought to evaluate the specificity of SUGARWIN2 to better understand its mechanism of action against phytopathogens and the associations between fungi and insects that affect plants. We used Colletotrichum falcatum, a fungus that causes red rot disease in sugarcane fields infested by D. saccharalis, and Ceratocystis paradoxa, which causes pineapple disease in sugarcane. We also tested whether SUGARWIN2 is able to cause cell death in Aspergillus nidulans, a fungus that does not infect sugarcane, and in the model yeast Saccharomyces cerevisiae, which is used for bioethanol production. Recombinant SUGARWIN2 altered C. falcatum morphology by increasing vacuolization, points of fractures and a leak of intracellular material, leading to germling apoptosis. In C. paradoxa, SUGARWIN2 showed increased vacuolization in hyphae but did not kill the fungi. Neither the non-pathogenic fungus A. nidulans nor the yeast S. cerevisiae was affected by recombinant SUGARWIN2, suggesting that the protein is specific to sugarcane opportunistic fungal pathogens.

(Cucumis melo L.) cultivars to soil-borne plant pathogenic fungi in Iran

African Journals Online (AJOL)

ajl11

2012-10-30

Oct 30, 2012 ... Melon is an important dessert fruit in the Sistan region of. Iran, but its cultivation is threatened by attacks of. Macrophomina phaseolina (Tassi), Monosporascus cannonballus (Pollack and Uecker) and Rhizoctonia solani (Kuhn) (Safarnezhad, 2004). Melon death induced by these soil-borne plant pathogenic ...

Mycoviruses of filamentous fungi and their relevance to plant pathology.

Science.gov (United States)

Pearson, Michael N; Beever, Ross E; Boine, Barbara; Arthur, Kieren

2009-01-01

Mycoviruses (fungal viruses) are reviewed with emphasis on plant pathogenic fungi. Based on the presence of virus-like particles and unencapsidated dsRNAs, mycoviruses are common in all major fungal groups. Over 80 mycovirus species have been officially recognized from ten virus families, but a paucity of nucleic acid sequence data makes assignment of many reported mycoviruses difficult. Although most of the particle types recognized to date are isometric, a variety of morphologies have been found and, additionally, many apparently unencapsidated dsRNAs have been reported. Until recently, most characterized mycoviruses have dsRNA genomes, but ssRNA mycoviruses now constitute about one-third of the total. Two hypotheses for the origin of mycoviruses of plant pathogens are discussed: the first that they are of unknown but ancient origin and have coevolved along with their hosts, the second that they have relatively recently moved from a fungal plant host into the fungus. Although mycoviruses are typically readily transmitted through asexual spores, transmission through sexual spores varies with the host fungus. Evidence for natural horizontal transmission has been found. Typically, mycoviruses are apparently symptomless (cryptic) but beneficial effects on the host fungus have been reported. Of more practical interest to plant pathologists are those viruses that confer a hypovirulent phenotype, and the scope for using such viruses as biocontrol agents is reviewed. New tools are being developed based on host genome studies that will help to address the intellectual challenge of understanding the fungal-virus interactions and the practical challenge of manipulating this relationship to develop novel biocontrol agents for important plant pathogens.

The complexity of nitrogen metabolism and nitrogen-regulated gene expression in plant pathogenic fungi

NARCIS (Netherlands)

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

2008-01-01

Plant pathogens secrete effector molecules that contribute to the establishment of disease in their plant hosts. The identification of cellular cues that regulate effector gene expression is an important aspect of understanding the infection process. Nutritional status in the cell has been

Phylogenetic congruence between subtropical trees and their associated fungi.

Science.gov (United States)

Liu, Xubing; Liang, Minxia; Etienne, Rampal S; Gilbert, Gregory S; Yu, Shixiao

2016-12-01

Recent studies have detected phylogenetic signals in pathogen-host networks for both soil-borne and leaf-infecting fungi, suggesting that pathogenic fungi may track or coevolve with their preferred hosts. However, a phylogenetically concordant relationship between multiple hosts and multiple fungi in has rarely been investigated. Using next-generation high-throughput DNA sequencing techniques, we analyzed fungal taxa associated with diseased leaves, rotten seeds, and infected seedlings of subtropical trees. We compared the topologies of the phylogenetic trees of the soil and foliar fungi based on the internal transcribed spacer (ITS) region with the phylogeny of host tree species based on matK , rbcL , atpB, and 5.8S genes. We identified 37 foliar and 103 soil pathogenic fungi belonging to the Ascomycota and Basidiomycota phyla and detected significantly nonrandom host-fungus combinations, which clustered on both the fungus phylogeny and the host phylogeny. The explicit evidence of congruent phylogenies between tree hosts and their potential fungal pathogens suggests either diffuse coevolution among the plant-fungal interaction networks or that the distribution of fungal species tracked spatially associated hosts with phylogenetically conserved traits and habitat preferences. Phylogenetic conservatism in plant-fungal interactions within a local community promotes host and parasite specificity, which is integral to the important role of fungi in promoting species coexistence and maintaining biodiversity of forest communities.

Pathogenicity of Nectriaceous Fungi on Avocado in Australia.

Science.gov (United States)

Parkinson, Louisamarie E; Shivas, Roger G; Dann, Elizabeth K

2017-12-01

Black root rot is a severe disease of young avocado trees in Australia causing black necrotic roots, tree stunting, and leaf drop prior to tree death. Nectriaceous fungi (Nectriaceae, Hypocreales), are commonly isolated from symptomatic roots. This research tested the pathogenicity of 19 isolates from Calonectria, Cylindrocladiella, Dactylonectria, Gliocladiopsis, and Ilyonectria, spp. collected from young avocado trees and other hosts. Glasshouse pathogenicity tests with 'Reed' avocado (Persea americana) seedlings confirmed that Calonectria ilicicola is a severe pathogen of avocado, causing stunting, wilting, and seedling death within 5 weeks of inoculation. Isolates of C. ilicicola from peanut, papaya, and custard apple were also shown to be aggressive pathogens of avocado, demonstrating a broad host range. An isolate of a Calonectria sp. from blueberry and avocado isolates of Dactylonectria macrodidyma, D. novozelandica, D. pauciseptata, and D. anthuriicola caused significant root rot but not stunting within 5 to 9 weeks of inoculation. An isolate of an Ilyonectria sp. from grapevine closely related to Ilyonectria liriodendri, and avocado isolates of Cylindrocladiella pseudoinfestans, Gliocladiopsis peggii, and an Ilyonectria sp. were not pathogenic to avocado.

Oligo-DNA custom macroarray for monitoring major pathogenic and non-pathogenic fungi and bacteria in the phyllosphere of apple trees.

Science.gov (United States)

He, Ying-Hong; Isono, Sayaka; Shibuya, Makoto; Tsuji, Masaharu; Adkar Purushothama, Charith-Raj; Tanaka, Kazuaki; Sano, Teruo

2012-01-01

To monitor the richness in microbial inhabitants in the phyllosphere of apple trees cultivated under various cultural and environmental conditions, we developed an oligo-DNA macroarray for major pathogenic and non-pathogenic fungi and bacteria inhabiting the phyllosphere of apple trees. First, we isolated culturable fungi and bacteria from apple orchards by an agar-plate culture method, and detected 32 fungal and 34 bacterial species. Alternaria, Aureobasidium, Cladosporium, Rhodotorula, Cystofilobasidium, and Epicoccum genera were predominant among the fungi, and Bacillus, Pseudomonas, Sphingomonas, Methylobacterium, and Pantoea genera were predominant among the bacteria. Based on the data, we selected 29 major non-pathogenic and 12 phytopathogenic fungi and bacteria as the targets of macroarray. Forty-one species-specific 40-base pair long oligo-DNA sequences were selected from the nucleotide sequences of rDNA-internal transcribed spacer region for fungi and 16S rDNA for bacteria. The oligo-DNAs were fixed on nylon membrane and hybridized with digoxigenin-labeled cRNA probes prepared for each species. All arrays except those for Alternaria, Bacillus, and their related species, were specifically hybridized. The array was sensitive enough to detect 10(3) CFU for Aureobasidium pullulans and Bacillus cereus. Nucleotide sequencing of 100 each of independent fungal rDNA-ITS and bacterial 16S-rDNA sequences from apple tree was in agreement with the macroarray data obtained using the same sample. Finally, we analyzed the richness in the microbial inhabitants in the samples collected from apple trees in four orchards. Major apple pathogens that cause scab, Alternaria blotch, and Marssonina blotch were detected along with several non-phytopathogenic fungal and bacterial inhabitants. The macroarray technique presented here is a strong tool to monitor the major microbial species and the community structures in the phyllosphere of apple trees and identify key species

Oligo-DNA custom macroarray for monitoring major pathogenic and non-pathogenic fungi and bacteria in the phyllosphere of apple trees.

Directory of Open Access Journals (Sweden)

Ying-Hong He

Full Text Available BACKGROUND: To monitor the richness in microbial inhabitants in the phyllosphere of apple trees cultivated under various cultural and environmental conditions, we developed an oligo-DNA macroarray for major pathogenic and non-pathogenic fungi and bacteria inhabiting the phyllosphere of apple trees. METHODS AND FINDINGS: First, we isolated culturable fungi and bacteria from apple orchards by an agar-plate culture method, and detected 32 fungal and 34 bacterial species. Alternaria, Aureobasidium, Cladosporium, Rhodotorula, Cystofilobasidium, and Epicoccum genera were predominant among the fungi, and Bacillus, Pseudomonas, Sphingomonas, Methylobacterium, and Pantoea genera were predominant among the bacteria. Based on the data, we selected 29 major non-pathogenic and 12 phytopathogenic fungi and bacteria as the targets of macroarray. Forty-one species-specific 40-base pair long oligo-DNA sequences were selected from the nucleotide sequences of rDNA-internal transcribed spacer region for fungi and 16S rDNA for bacteria. The oligo-DNAs were fixed on nylon membrane and hybridized with digoxigenin-labeled cRNA probes prepared for each species. All arrays except those for Alternaria, Bacillus, and their related species, were specifically hybridized. The array was sensitive enough to detect 10(3 CFU for Aureobasidium pullulans and Bacillus cereus. Nucleotide sequencing of 100 each of independent fungal rDNA-ITS and bacterial 16S-rDNA sequences from apple tree was in agreement with the macroarray data obtained using the same sample. Finally, we analyzed the richness in the microbial inhabitants in the samples collected from apple trees in four orchards. Major apple pathogens that cause scab, Alternaria blotch, and Marssonina blotch were detected along with several non-phytopathogenic fungal and bacterial inhabitants. CONCLUSIONS: The macroarray technique presented here is a strong tool to monitor the major microbial species and the community structures in

Microbial pathogens in source and treated waters from drinking water treatment plants in the US

Science.gov (United States)

An occurrence survey was conducted on selected pathogens in source and treated drinking water collected from 25 drinking water treatment plants (DWTPs) in the United States. Water samples were analyzed for the protozoa Giardia and Cryptosporidium (EPA Method 1623); the fungi Asp...

Molecular and phenotypic characterization of anamorphic fungi

OpenAIRE

Madrid Lorca, Hugo

2011-01-01

Anamorphic fungi (those reproducing asexually) are a big part of kingdom Fungi. Most of them occur as saprobes in nature, but numerous species are pathogenic to plants and animals including man. With the aim of contributing to the knowledge of the diversity and distribution of anamorphic fungi, we performed a phenotypic and molecular characterization of environmental and clinical isolates of these fungi. Based on a polyphasic taxonomy approach which included morphology, physiology and DNA seq...

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.

Early planting and hand sorting effectively controls seed-borne fungi in farm-retained bean seed

Directory of Open Access Journals (Sweden)

Ernest Dube

2014-11-01

Full Text Available Home-saved bean (Phaseolus vulgaris L. seed can be hand-sorted to remove discoloured seed, thereby reducing the level of contamination by certain seed-borne fungi and improving seed germination. In this study, the effect of planting date on the infection and discolouration of bean seed by seed-borne fungi was investigated in order to improve the quality of hand-sorted, farm-retained bean seeds used by resource poor smallholder farmers. The germination quality and level of seed-borne fungi in hand-sorted first-generation bean seed harvested from an early-, mid- and late-summer season planted crop was therefore assessed. The highest percentage of discoloured seed (68% was obtained from the mid-summer season planting. Non-discoloured seed from early- and late-season plantings had significantly (p"less than"0.001 higher normal germination (82% and 77%, respectively than that from the mid-season planting date (58%. Irrespective of planting date, unsorted seed and discoloured seed had higher levels of infection by Fusarium spp. and Phaeoisariopsis spp. than the non-discoloured seed. Removal of discoloured seed by hand sorting eliminated Rhizoctonia spp. from all seed lots. Farmers can eliminate this pathogen by simply removing discoloured seed. Non-discoloured seed from the early-planted crop had the lowest level of infection by Fusarium spp. and Phaeoisariopsis spp. The results indicate that planting date is an important consideration in improving the quality of hand-sorted farm-retained bean seed.

Lifestyle transitions in plant pathogenic Colletotrichum fungi deciphered by genome and transcriptome analyses

NARCIS (Netherlands)

O'Connell, R.J.; Thon, M.R.; Hacquard, S.; Amyotte, S.G.; Kleemann, J.; Torres, M.F.; Damm, U.; Buiate, E.A.; Epstein, L.; Alkan, N.; Altmuller, J.; Alvarado-Balderrama, L.; Bauser, C.A.; Becker, C.; Birren, B.W.; Chen, Z.; Choi, J.; Crouch, J.A.; Duvick, J.P.; Farman, M.A.; Gan, P.; Heiman, D.; Henrissat, B.; Howard, R.J.; Kabbage, M.; Koch, C.; Kracher, B.; Kubo, Y.; Law, A.D.; Lebrun, M.-H.; Lee, Y.-H.; Miyara, I.; Moore, N.; Neumann, U.; Nordstrom, K.; Panaccione, D.G.; Panstruga, R.; Place, M.; Proctor, R.H.; Prusky, D.; Rech, G.; Reinhardt, R.; Rollins, J.A.; Rounsley, S.; Schardl, C.L.; Schwartz, D.C.; Shenoy, N.; Shirasu, K.; Sikhakolli, U.R.; Stuber, K.; Sukno, S.A.; Sweigard, J.A.; Takano, Y.; Takahara, H.; Trail, F.; Does, H.C.; Voll, L.M.; Will, I.; Young, S.; Zeng, Q.; Zhang, Jingze; Zhou, S.; Dickman, M.B.; Schulze-Lefert, P.; Verloren van Themaat, E.; Ma, L.-J.; Vaillancourt, L.J.

2012-01-01

Colletotrichum species are fungal pathogens that devastate crop plants worldwide. Host infection involves the differentiation of specialized cell types that are associated with penetration, growth inside living host cells (biotrophy) and tissue destruction (necrotrophy). We report here genome and

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.

Role and influence of mycorrhizal fungi on radiocesium accumulation by plants

International Nuclear Information System (INIS)

Dupre de Boulois, H.; Joner, E.J.; Leyval, C.; Jakobsen, I.; Chen, B.D.; Roos, P.; Thiry, Y.; Rufyikiri, G.; Delvaux, B.; Declerck, S.

2008-01-01

This review summarizes current knowledge on the contribution of mycorrhizal fungi to radiocesium immobilization and plant accumulation. These root symbionts develop extended hyphae in soils and readily contribute to the soil-to-plant transfer of some nutrients. Available data show that ecto-mycorrhizal (ECM) fungi can accumulate high concentration of radiocesium in their extraradical phase while radiocesium uptake and accumulation by arbuscular mycorrhizal (AM) fungi is limited. Yet, both ECM and AM fungi can transport radiocesium to their host plants, but this transport is low. In addition, mycorrhizal fungi could thus either store radiocesium in their intraradical phase or limit its root-to-shoot translocation. The review discusses the impact of soil characteristics, and fungal and plant transporters on radiocesium uptake and accumulation in plants, as well as the potential role of mycorrhizal fungi in phytoremediation strategies

Role and influence of mycorrhizal fungi on radiocesium accumulation by plants

Energy Technology Data Exchange (ETDEWEB)

Dupre de Boulois, H. [Universite catholique de Louvain, Unite de Microbiologie, Croix du Sud 3, 1348 Louvain-la-Neuve (Belgium); Joner, E.J. [Bioforsk Soil and Environment, FredrikA Dahls vei 20, N-1432 As (Norway); Leyval, C. [LIMOS, Nancy University, CNRS, Faculte des Sciences, BP239, 54506 Vandoeuvre-les-Nancy, Cedex (France); Jakobsen, I. [Biosystems Department, Riso National Laboratory, Technical University of Denmark, DK-4000 Roskilde (Denmark); Chen, B.D. [Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Roos, P. [Radiation Research Department, Riso National Laboratory, Technical University of Denmark, DK-4000 Roskilde (Denmark); Thiry, Y.; Rufyikiri, G. [Biosphere Impact Assessment, SCK.CEN, Foundation of Public Utility, 200 Boeretang, 2400 Mol (Belgium); Delvaux, B. [Universite catholique de Louvain, Unite des Sciences du Sol, Croix du Sud 2/10, 1348 Louvain-la-Neuve (Belgium); Declerck, S. [Universite catholique de Louvain, Unite de Microbiologie, Croix du Sud 3, 1348 Louvain-la-Neuve (Belgium)], E-mail: declerck@mbla.ucl.ac.be

2008-05-15

This review summarizes current knowledge on the contribution of mycorrhizal fungi to radiocesium immobilization and plant accumulation. These root symbionts develop extended hyphae in soils and readily contribute to the soil-to-plant transfer of some nutrients. Available data show that ecto-mycorrhizal (ECM) fungi can accumulate high concentration of radiocesium in their extraradical phase while radiocesium uptake and accumulation by arbuscular mycorrhizal (AM) fungi is limited. Yet, both ECM and AM fungi can transport radiocesium to their host plants, but this transport is low. In addition, mycorrhizal fungi could thus either store radiocesium in their intraradical phase or limit its root-to-shoot translocation. The review discusses the impact of soil characteristics, and fungal and plant transporters on radiocesium uptake and accumulation in plants, as well as the potential role of mycorrhizal fungi in phytoremediation strategies.

Protecting Plants against Pests and Pathogens with Entomopathogenic Fungi

DEFF Research Database (Denmark)

Keyser, Chad Alton

This thesis investigates the natural occurrence of the fungal genus Metarhizium in association with crop-roots in Denmark, and advances the current understanding of how these fungi interact with other root-associating organisms when applied as a biological control agent. Insect-pest management...... protection. The fungal genus Metarhizium is one of the most intensely researched groups of entomopathogenic fungi and several isolates have been successfully employed as biopesticides for crop protection; however, inconsistent field reliability has limited wider implementation. Research emphasizing...... of the mycoparasitic fungus Clonostachys roseas to control Fusarium culmorum disease in wheat; and a significant level of insect mortality was observed in insects feeding on roots from inoculated seed – even when Metarhizium was applied jointly with C. rosea. Furthermore, M. flavoviride, a less frequently studied...

High diversity of fungi in air particulate matter.

Science.gov (United States)

Fröhlich-Nowoisky, Janine; Pickersgill, Daniel A; Després, Viviane R; Pöschl, Ulrich

2009-08-04

Fungal spores can account for large proportions of air particulate matter, and they may potentially influence the hydrological cycle and climate as nuclei for water droplets and ice crystals in clouds, fog, and precipitation. Moreover, some fungi are major pathogens and allergens. The diversity of airborne fungi is, however, not well-known. By DNA analysis we found pronounced differences in the relative abundance and seasonal cycles of various groups of fungi in coarse and fine particulate matter, with more plant pathogens in the coarse fraction and more human pathogens and allergens in the respirable fine particle fraction (<3 microm). Moreover, the ratio of Basidiomycota to Ascomycota was found to be much higher than previously assumed, which might also apply to the biosphere.

β-1,3-1,4-glucanase gene from Bacillus velezensis ZJ20 exerts antifungal effect on plant pathogenic fungi.

Science.gov (United States)

Xu, Ting; Zhu, Tianhui; Li, Shujiang

2016-02-01

Bacillus velezensis is a known antifungal bacteria. To understand the role of β-1, 3-1, 4-glucanase played on B. velezensis about the mechanism which exerts effect on fungi, we isolated and cloned the β-1, 3-1, 4-glucanase gene (Bglu1) from B. velezensis ZJ20. The Bglu1 open reading frame was 732 bp that encoded a protein with 243 amino acids and a calculated molecular weight of 27.3 kDa. The same gene without the signal peptide, termed Bglu2, was also cloned and expressed in E. coli BL21. Among the two variants, only Bglu2 protein was expressed. Purified Bglu2 could be eluted with imidazole solution at concentrations ranging from 100 to 500 mM although the highest expression was observed at 150 and 200 mM and the purest was at 500 mM. In addition, activity of the crude enzyme was 1527 U ml(-1) and the highest activity of the purified enzyme was 1706 U ml(-1). The purified β-1, 3-1, 4-glucanase had activity on a wide range of pH and temperatures and displayed optimal activity at pH 5.0 and 35 °C. More importantly, the mycelial morphology of three pathogenic fungi was destroyed by the purified β-1, 3-1, 4-glucanase. In conclusion, β-1, 3-1, 4-glucanase from B. velezensis ZJ20 can be highly expressed in E. coli BL21 and the recombinant protein is pathogenic to fungi.

Arbuscular and Ectomycorrhizal Fungi Associated with the Invasive Brazilian Pepper Tree (Schinus terebinthifolius) and Two Native Plants in South Florida

Science.gov (United States)

Dawkins, Karim; Esiobu, Nwadiuto

2017-01-01

The potential role of soil fungi in the invasion of the Brazilian pepper tree (Schinus terebinthifolius—BP) in Florida is not known; although the low biotic resistance of Florida soils is often invoked to explain the prevalence of many invasive species. To gain an initial insight into BP's mycorrhizal associations, this study examined the rhizobiome of BP and two native plants (Hamelia patens and Bidens alba) across six locations. Arbuscular mycorrhizal fungi (AMF) associated with the roots of the target plants and bulk soil was characterized by spore morphotyping. Sequence analysis of metagenomic DNA from lateral roots/rhizosphere of BP (n = 52) and a native shrub H. patens (n = 37) on the same parcel yielded other fungal associates. Overall, the total population of AMF associated with BP was about two folds greater than that of the two native plants (p = 0.0001) growing on the same site. The dominant AMF under Schinus were members of the common Glomus and Rhizophagus spp. By contrast, the most prevalent AMF in the bulk soil and rhizosphere of the two Florida native plants, Acaulospora spp (29%) was sharply diminished (9%) under BP rhizosphere. Analysis of the ITS2 sequences also showed that Schinus rhizosphere had a high relative abundance of ectomycorrhizal fungi (76.5%) compared to the native H. patens (2.6%), with the species Lactifluus hygrophoroides (Basidiomycota) being the most prevalent at 61.5% (p < 0.05). Unlike the native plants where pathogenic fungi like Phyllosticta sp., Phoma sp., and Neofusicoccum andium were present (8.1% for H. patens), only one potentially pathogenic fungal taxon was detected (3.9%) under BP. The striking disparity in the relative abundance of AMF and other fungal types between BP and the native species is quite significant. Fungal symbionts could aide plant invasion via resource-use efficiency and other poorly defined mechanisms of protection from pathogens in their invaded range. This report exposes a potentially

Effectors from Wheat Rust Fungi Suppress Multiple Plant Defense Responses.

Science.gov (United States)

Ramachandran, Sowmya R; Yin, Chuntao; Kud, Joanna; Tanaka, Kiwamu; Mahoney, Aaron K; Xiao, Fangming; Hulbert, Scot H

2017-01-01

Fungi that cause cereal rust diseases (genus Puccinia) are important pathogens of wheat globally. Upon infection, the fungus secretes a number of effector proteins. Although a large repository of putative effectors has been predicted using bioinformatic pipelines, the lack of available high-throughput effector screening systems has limited functional studies on these proteins. In this study, we mined the available transcriptomes of Puccinia graminis and P. striiformis to look for potential effectors that suppress host hypersensitive response (HR). Twenty small (wheat, confirming its activity in a homologous system. Overall, this study provides the first evidence for the presence of effectors in Puccinia species suppressing multiple plant defense responses.

Culturable fungi in potting soils and compost.

Science.gov (United States)

Haas, Doris; Lesch, Susanne; Buzina, Walter; Galler, Herbert; Gutschi, Anna Maria; Habib, Juliana; Pfeifer, Bettina; Luxner, Josefa; Reinthaler, Franz F

2016-11-01

In the present study the spectrum and the incidence of fungi in potting soils and compost was investigated. Since soil is one of the most important biotopes for fungi, relatively high concentrations of fungal propagules are to be expected. For detection of fungi, samples of commercial soils, compost and soils from potted plants (both surface and sub-surface) were suspended and plated onto several mycological media. The resulting colonies were evaluated qualitatively and quantitatively. The results from the different sampling series vary, but concentrations on the surface of potted plants and in commercial soils are increased tenfold compared to compost and sub-surface soils. Median values range from 9.5 × 10(4) colony forming units (CFU)/g to 5.5 × 10(5) CFU/g. The spectrum of fungi also varies in the soils. However, all sampling series show high proportion of Aspergillus and Penicillium species, including potentially pathogenic species such as Aspergillus fumigatus. Cladosporium, a genus dominant in the ambient air, was found preferably in samples which were in contact with the air. The results show that potentially pathogenic fungi are present in soils. Immunocompromised individuals should avoid handling soils or potted plants in their immediate vicinity. © The Author 2016. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Phylogeny and comparative genome analysis of a Basidiomycete fungi

Energy Technology Data Exchange (ETDEWEB)

Riley, Robert W.; Salamov, Asaf; Grigoriev, Igor; Hibbett, David

2011-03-14

Fungi of the phylum Basidiomycota, make up some 37percent of the described fungi, and are important from the perspectives of forestry, agriculture, medicine, and bioenergy. This diverse phylum includes the mushrooms, wood rots, plant pathogenic rusts and smuts, and some human pathogens. To better understand these important fungi, we have undertaken a comparative genomic analysis of the Basidiomycetes with available sequenced genomes. We report a phylogeny that sheds light on previously unclear evolutionary relationships among the Basidiomycetes. We also define a `core proteome? based on protein families conserved in all Basidiomycetes. We identify key expansions and contractions in protein families that may be responsible for the degradation of plant biomass such as cellulose, hemicellulose, and lignin. Finally, we speculate as to the genomic changes that drove such expansions and contractions.

Pathogen and biological contamination management in plant tissue culture: phytopathogens, vitro pathogens, and vitro pests.

Science.gov (United States)

Cassells, Alan C

2012-01-01

The ability to establish and grow plant cell, organ, and tissue cultures has been widely exploited for basic and applied research, and for the commercial production of plants (micro-propagation). Regardless of whether the application is for research or commerce, it is essential that the cultures be established in vitro free of biological contamination and be maintained as aseptic cultures during manipulation, growth, and storage. The risks from microbial contamination are spurious experimental results due to the effects of latent contaminants or losses of valuable experimental or commercial cultures. Much of the emphasis in culture contamination management historically focussed on the elimination of phytopathogens and the maintenance of cultures free from laboratory contamination by environmental bacteria, fungi (collectively referred to as "vitro pathogens", i.e. pathogens or environmental micro-organisms which cause culture losses), and micro-arthropods ("vitro pests"). Microbial contamination of plant tissue cultures is due to the high nutrient availability in the almost universally used Murashige and Skoog (Physiol Plant 15:473-497, 1962) basal medium or variants of it. In recent years, it has been shown that many plants, especially perennials, are at least locally endophytically colonized intercellularly by bacteria. The latter, and intracellular pathogenic bacteria and viruses/viroids, may pass latently into culture and be spread horizontally and vertically in cultures. Growth of some potentially cultivable endophytes may be suppressed by the high salt and sugar content of the Murashige and Skoog basal medium and suboptimal temperatures for their growth in plant tissue growth rooms. The management of contamination in tissue culture involves three stages: disease screening (syn. disease indexing) of the stock plants with disease and endophyte elimination where detected; establishment and pathogen and contaminant screening of established initial cultures

Solar photocatalytic disinfection of agricultural pathogenic fungi (Curvularia sp.) in real urban wastewater.

Science.gov (United States)

Aguas, Yelitza; Hincapie, Margarita; Fernández-Ibáñez, Pilar; Polo-López, María Inmaculada

2017-12-31

The interest in developing alternative water disinfection methods that increase the access to irrigation water free of pathogens for agricultural purposes is increasing in the last decades. Advanced Oxidation Processes (AOPs) have been demonstrated to be very efficient for the abatement of several kind of pathogens in contaminated water. The purpose of the current study was to evaluate and compare the capability of several solar AOPs for the inactivation of resistant spores of agricultural fungi. Solar photoassisted H 2 O 2 , solar photo-Fenton at acid and near-neutral pH, and solar heterogeneous photocatalysis using TiO 2, with and without H 2 O 2 , have been studied for the inactivation of spores of Curvularia sp., a phytopathogenic fungi worldwide found in soils and crops. Different concentrations of reagents and catalysts were evaluated at bench scale (solar vessel reactors, 200mL) and at pilot plant scale (solar Compound Parabolic Collector-CPC reactor, 20L) under natural solar radiation using distilled water (DW) and real secondary effluents (SE) from a municipal wastewater treatment plant. Inactivation order of Curvularia sp. in distilled water was determined, i.e. TiO 2 /H 2 O 2 /sunlight (100/50mgL -1 )>H 2 O 2 /sunlight (40mgL -1 )>TiO 2 /sunlight (100mgL -1 )>photo-Fenton with 5/10mgL -1 of Fe 2+ /H 2 O 2 at pH3 and near-neutral pH. For the case of SE, at near neutral pH, the most efficient solar process was H 2 O 2 /Solar (60mgL -1 ); nevertheless, the best Curvularia sp. inactivation rate was obtained with photo-Fenton (10/20mgL -1 of Fe 2+ /H 2 O 2 ) requiring a previous water adicification to pH3, within 300 and 210min of solar treatment, respectively. These results show the efficiency of solar AOPs as a feasible option for the inactivation of resistant pathogens in water for crops irrigation, even in the presence of organic matter (average Dissolved Organic Carbon (DOC): 24mgL -1 ), and open a window for future wastewater reclamation and irrigation

Evaluation of fungicidal and fungistatic activity of plant essential oils towards plant pathogenic and saprophytic fungi

Directory of Open Access Journals (Sweden)

Zia BANIHASHEMI

2011-09-01

Full Text Available   The contact and vapor effects of essential oils from different plants were studied in vitro for fungicidal and fungistatic activity towards different Basidiomycete, Ascomycete, Zygomycete and Oomycete taxa. Of nine essential oils tested, most were fungicidal at very low concentrations to most of the fungi. Hyphae were more sensitive than spores to the formulations. The essential oils citral, β-citronellol, geraniol and oil of lavender, at 1 μL mL-1 medium or 12 μL L-1 of air, inhibited growth and germination in the fungal species examined. Different species of fungal genera reacted differently to the formulations. Some of the formulations were fungistatic to spore germination.

Morphological characteristics and pathogenicity of fungi associated with Roselle (Hibiscus Sabdariffa) diseases in Penang, Malaysia.

Science.gov (United States)

Eslaminejad, Touba; Zakaria, Maziah

2011-11-01

Roselle, or Jamaica sorrel (Hibiscus sabdariffa) is a popular vegetable in many tropical regions, cultivated for its leaves, seeds, stems and calyces which, the dried calyces are used to prepare tea, syrup, jams and jellies and as beverages. The main objectives of this study were to identify and characterise fungal pathogens associated with Roselle diseases based on their morphological and cultural characteristics and to determine the pathogenicity of four fungi infecting Roselle seedlings, namely Phoma exigua, Fusarium nygamai, Fusarium tgcq and Rhizoctonia solani in Penang. A total of 200 fungal isolates were obtained from 90 samples of symptomatic Roselle tissues. The isolates were identified based on cultural and morphological characteristics, as well as their pathogenicity. The fungal pathogen most frequently isolated was P. exigua (present in 45% of the samples), followed by F. nygamai (25%), Rhizoctonia solani (19%) and F. camptoceras (11%). Pathogenicity tests showed that P. exigua, F. nygamai, F. camptoceras and R. solani were able to infect both wounded and unwounded seedlings with different degrees of severity as indicated by the Disease severity (DS). R. solani was the most pathogenic fungus affecting both wounded and unwounded Roselle seedlings, followed by P. exigua that was highly pathogenic on wounded seedlings. F. nygamai was less pathogenic while the least pathogenic fungus was F. camptoceras, infecting only the unwounded seedlings but, surprisingly, not the wounded plants. Copyright © 2011 Elsevier Ltd. All rights reserved.

Fungos endofíticos associados a plantas medicinais Endophytic fungi associated with medicinal plants

Directory of Open Access Journals (Sweden)

V Mussi-Dias

2012-01-01

properties, as well as the quality of the stored and commercialized product. Therefore, the aim of this study was to isolate and identify the endophytic flora from eleven randomly chosen medicinal species. Pure cultures were obtained from the fungi Phomopsis, Colletotrichum, Pestalotia, Trichoderma, Fusarium, Nigrospora and Glomerella endophytically occurring in Plectranthus barbatus, Vernonia condensata, Pfaffia paniculata, Foeniculum vulgare, Cymbopogon citratus, Cymbopogon nardus, Cordia curassavica, Maytenus ilicifolia, Punica granatum, Morus nigra and Bauhinia forficata. The plant species that presented the highest number of endophytic fungi were Vernonia condensata, Punica granatum and Morus nigra. All fungi recovered in this study showed strictly endophytic features, not manifesting pathogenicity in their host species. Among the detected fungi, special attention must be given to the genus Fusarium, since a wide range of species of this genus are known to produce mycotoxins and constitute important post-harvest pathogens.

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.

Resistance to cereal rusts at the plant cell wall - what can we learn from other host-pathogen systems?

NARCIS (Netherlands)

Collins, N.C.; Niks, R.E.; Schulze-Lefert, P.

2007-01-01

The ability of plant cells to resist invasion by pathogenic fungi at the cell periphery (pre-invasion resistance) differs from other types of resistance that are generally triggered after parasite entry and during differentiation of specialised intracellular feeding structures. Genetic sources of

Entomopathogenic Fungi: New Insights into Host-Pathogen Interactions.

Science.gov (United States)

Butt, T M; Coates, C J; Dubovskiy, I M; Ratcliffe, N A

2016-01-01

Although many insects successfully live in dangerous environments exposed to diverse communities of microbes, they are often exploited and killed by specialist pathogens. Studies of host-pathogen interactions (HPI) provide valuable insights into the dynamics of the highly aggressive coevolutionary arms race between entomopathogenic fungi (EPF) and their arthropod hosts. The host defenses are designed to exclude the pathogen or mitigate the damage inflicted while the pathogen responds with immune evasion and utilization of host resources. EPF neutralize their immediate surroundings on the insect integument and benefit from the physiochemical properties of the cuticle and its compounds that exclude competing microbes. EPF also exhibit adaptations aimed at minimizing trauma that can be deleterious to both host and pathogen (eg, melanization of hemolymph), form narrow penetration pegs that alleviate host dehydration and produce blastospores that lack immunogenic sugars/enzymes but facilitate rapid assimilation of hemolymph nutrients. In response, insects deploy an extensive armory of hemocytes and macromolecules, such as lectins and phenoloxidase, that repel, immobilize, and kill EPF. New evidence suggests that immune bioactives work synergistically (eg, lysozyme with antimicrobial peptides) to combat infections. Some proteins, including transferrin and apolipophorin III, also demonstrate multifunctional properties, participating in metabolism, homeostasis, and pathogen recognition. This review discusses the molecular intricacies of these HPI, highlighting the interplay between immunity, stress management, and metabolism. Increased knowledge in this area could enhance the efficacy of EPF, ensuring their future in integrated pest management programs. Copyright © 2016 Elsevier Inc. All rights reserved.

Vertebrate Endothermy Restricts Most Fungi as Potential Pathogens

NARCIS (Netherlands)

Robert, V.A.R.G.; Casadevall, A.

2009-01-01

The paucity of fungal diseases in mammals relative to insects, amphibians, and plants is puzzling. We analyzed the thermal tolerance of 4802 fungal strains from 144 genera and found that most cannot grow at mammalian temperatures. Fungi from insects and mammals had greater thermal tolerances than

Isolation and evaluation of endophytic fungi with antimicrobial ability from Phyllostachys edulis

Directory of Open Access Journals (Sweden)

Xiaoye Shen

2012-12-01

Full Text Available Endophytic fungi (30 isolates from bamboo branches were categorized into 12 genera, based on the blast analyses of ITS nrDNA sequence in GenBank and microscopic examination. The aim of this work was to investigate the antibacterial and antifungal activities of endophytic fungi. Inhibitory effects against clinical pathogens and phytopathogens have been screened for all the isolates preliminarily and strains tentatively identified as Cladosporium sphaerospermum (PE106, Simplicillium lanosoniveum (PE120, Curvularia sp. (PE127, Didymella sp. (PE128 and Penicillium cf. raistrickii (PE130 presented bioactivity against at least four tested pathogens using the agar diffusion method. Crude extracts of PE106, PE120, PE127 and PE130 displayed broad-spectrum activity against plant pathogenic fungi by mycelial radial growth test. All of the four isolates were found to have high bioactivity against the frequent plant pathogenic fungus Botryotinia fuckeliana, and two of the isolates (PE120 and PE130 also inhibited the growth of phytopathogen Thanatephorus cucumeris noteworthily. This study is the first report on the antimicrobial activity of endophytic fungi associated with branches of Ph. edulis.

Calcium homeostasis and signaling in fungi and their relevance for pathogenicity of yeasts and filamentous fungi

Directory of Open Access Journals (Sweden)

Renata Tisi

2016-09-01

Full Text Available Though fungi show peculiarities in the purposes and specific traits of calcium signaling pathways, the general scheme and the most important players are well conserved if compared to higher eukaryotes. This provides a powerful opportunity either to investigate shared features using yeast as a model or to exploit fungal specificities as potential targets for antifungal therapies. The sequenced genomes from yeast Saccharomyces cerevisiae, Schizosaccharomyces pombe and the filamentous fungus Neurospora crassa were already published more than ten years ago. More recently the genome sequences of filamentous fungi of Aspergillus genus, some of which threatening pathogens, and dimorphic fungi Ustilago maydis were published, giving the chance to identify several proteins involved in calcium signaling based on their homology to yeast or mammalian counterparts. Nonetheless, unidentified calcium transporters are still present in these organisms which await to be molecularly characterized. Despite the relative simplicity in yeast calcium machinery and the availability of sophisticated molecular tools, in the last years, a number of new actors have been identified, albeit not yet fully characterized. This review will try to describe the state of the art in calcium channels and calcium signaling knowledge in yeast, with particular attention to the relevance of this knowledge with respect to pathological fungi.

In vitro effects of copper nanoparticles on plant pathogens, beneficial microbes and crop plants

Energy Technology Data Exchange (ETDEWEB)

Banik, S.; Pérez-de-Luque, A.

2017-07-01

Copper-based chemicals are effectively used as antimicrobials in agriculture. However, with respect to its nanoparticulate form there has been limited number of studies. In this investigation, in vitro tests on effect of copper nanoparticles (CuNPs) against plant pathogenic fungi, oomycete, bacteria, beneficial microbes Trichoderma harzianum and Rhizobium spp., and wheat seeds were conducted. Integration of CuNPs with non-nano copper like copper oxychloride (CoC) at 50 mg/L concentration each recorded 76% growth inhibition of the oomycete Phytophthora cinnamomi in vitro compared to the control. CuNPs also showed synergistic inhibitory effect with CoC on mycelial growth and sporulation of A. alternata. Pseudomonas syringae was inhibited at 200 mg/L of CuNPs. CuNPs were not significantly biocidal against Rhizobium spp. and Trichoderma harzianum compared to CoC. Evaluation of the effect of CuNP on wheat revealed that rate of germination of wheat seeds was higher in presence of CuNPs and CoC compared to control. Germination vigor index, root length, shoot dry weight and seed metabolic efficiency of wheat were negatively affected. At low concentration, CuNPs promoted the growth of the plant pathogenic fungi Botrytis fabae, Fusarium oxysporum f.sp. ciceris, F.oxysporum f.sp. melonis, Alternaria alternate and P. syringae, and sporulation of T. harzianum. Synergistic effect of CuNPs and CoC in inhibiting P. cinnamomi offers a possibility of developing new fungicide formulation for better control of the oomycetes. Non-biocidal effect of CuNPs against beneficial microbes indicates its potential use in the agri-ecosystem.

In vitro effects of copper nanoparticles on plant pathogens, beneficial microbes and crop plants

International Nuclear Information System (INIS)

Banik, S.; Pérez-de-Luque, A.

2017-01-01

Copper-based chemicals are effectively used as antimicrobials in agriculture. However, with respect to its nanoparticulate form there has been limited number of studies. In this investigation, in vitro tests on effect of copper nanoparticles (CuNPs) against plant pathogenic fungi, oomycete, bacteria, beneficial microbes Trichoderma harzianum and Rhizobium spp., and wheat seeds were conducted. Integration of CuNPs with non-nano copper like copper oxychloride (CoC) at 50 mg/L concentration each recorded 76% growth inhibition of the oomycete Phytophthora cinnamomi in vitro compared to the control. CuNPs also showed synergistic inhibitory effect with CoC on mycelial growth and sporulation of A. alternata. Pseudomonas syringae was inhibited at 200 mg/L of CuNPs. CuNPs were not significantly biocidal against Rhizobium spp. and Trichoderma harzianum compared to CoC. Evaluation of the effect of CuNP on wheat revealed that rate of germination of wheat seeds was higher in presence of CuNPs and CoC compared to control. Germination vigor index, root length, shoot dry weight and seed metabolic efficiency of wheat were negatively affected. At low concentration, CuNPs promoted the growth of the plant pathogenic fungi Botrytis fabae, Fusarium oxysporum f.sp. ciceris, F.oxysporum f.sp. melonis, Alternaria alternate and P. syringae, and sporulation of T. harzianum. Synergistic effect of CuNPs and CoC in inhibiting P. cinnamomi offers a possibility of developing new fungicide formulation for better control of the oomycetes. Non-biocidal effect of CuNPs against beneficial microbes indicates its potential use in the agri-ecosystem.

The effect of ectomycorrhizal fungi and bacteria on pine seedlings

Directory of Open Access Journals (Sweden)

Hanna Dahm

2014-08-01

Full Text Available The effect of ecomycorrhizal fungi (Hebelon crustuliniforme(Bull.: Fr. Quél. 5392 and Pisolithus tinctorius (Pers. Coker et Couch 5335 and bacteria (Bacillus polymyxa and Azospirillum brasilense. associated with mycorrhizas on the growth of pine seedligs was investigated. In addition the influence of bacteria on fungal biomass production and the relationship between ectomycorrhizal fungi and fungi pathogenic to root of pine seedlings were determined. In general, the shoot/root ratio was higher in plants inoculated with Hebeloma crustuliniforme and bacteria than in the control seedlings (grown only under sterile conditions. In non-sterile substrate the root/shoot ratio of the mycorrhizal seedlings was lower as compared to the control. Similar phenomenon was noted in plants inoculated with the mycorrhizal fungus Pisolithus tinetorius. The bacteria used as well as the time of introduction of these organisms into the cultures of mycorrhiza fungi affected the production of fungal biomass. Hebeloma crustuliniforme and Pisolithus tinctorius inhibited the growth of Rizoctonia solani and Fusarium oxysporum fungi pathogenic to pine seedlings.

The modular nature of dendritic cell responses to commensal and pathogenic fungi.

Directory of Open Access Journals (Sweden)

Lisa Rizzetto

Full Text Available The type of adaptive immune response following host-fungi interaction is largely determined at the level of the antigen-presenting cells, and in particular by dendritic cells (DCs. The extent to which transcriptional regulatory events determine the decision making process in DCs is still an open question. By applying the highly structured DC-ATLAS pathways to analyze DC responses, we classified the various stimuli by revealing the modular nature of the different transcriptional programs governing the recognition of either pathogenic or commensal fungi. Through comparison of the network parts affected by DC stimulation with fungal cells and purified single agonists, we could determine the contribution of each receptor during the recognition process. We observed that initial recognition of a fungus creates a temporal window during which the simultaneous recruitment of cell surface receptors can intensify, complement and sustain the DC activation process. The breakdown of the response to whole live cells, through the purified components, showed how the response to invading fungi uses a set of specific modules. We find that at the start of fungal recognition, DCs rapidly initiate the activation process. Ligand recognition is further enhanced by over-expression of the receptor genes, with a significant correspondence between gene expression and protein levels and function. Then a marked decrease in the receptor levels follows, suggesting that at this moment the DC commits to a specific fate. Overall our pathway based studies show that the temporal window of the fungal recognition process depends on the availability of ligands and is different for pathogens and commensals. Modular analysis of receptor and signalling-adaptor expression changes, in the early phase of pathogen recognition, is a valuable tool for rapid and efficient dissection of the pathogen derived components that determine the phenotype of the DC and thereby the type of immune response

Community Profiling of Fusarium in Combination with Other Plant-Associated Fungi in Different Crop Species Using SMRT Sequencing

Directory of Open Access Journals (Sweden)

Florian Walder

2017-11-01

Full Text Available Fusarium head blight, caused by fungi from the genus Fusarium, is one of the most harmful cereal diseases, resulting not only in severe yield losses but also in mycotoxin contaminated and health-threatening grains. Fusarium head blight is caused by a diverse set of species that have different host ranges, mycotoxin profiles and responses to agricultural practices. Thus, understanding the composition of Fusarium communities in the field is crucial for estimating their impact and also for the development of effective control measures. Up to now, most molecular tools that monitor Fusarium communities on plants are limited to certain species and do not distinguish other plant associated fungi. To close these gaps, we developed a sequencing-based community profiling methodology for crop-associated fungi with a focus on the genus Fusarium. By analyzing a 1600 bp long amplicon spanning the highly variable segments ITS and D1–D3 of the ribosomal operon by PacBio SMRT sequencing, we were able to robustly quantify Fusarium down to species level through clustering against reference sequences. The newly developed methodology was successfully validated in mock communities and provided similar results as the culture-based assessment of Fusarium communities by seed health tests in grain samples from different crop species. Finally, we exemplified the newly developed methodology in a field experiment with a wheat-maize crop sequence under different cover crop and tillage regimes. We analyzed wheat straw residues, cover crop shoots and maize grains and we could reveal that the cover crop hairy vetch (Vicia villosa acts as a potent alternative host for Fusarium (OTU F.ave/tri showing an eightfold higher relative abundance compared with other cover crop treatments. Moreover, as the newly developed methodology also allows to trace other crop-associated fungi, we found that vetch and green fallow hosted further fungal plant pathogens including Zymoseptoria tritici

Nests of Marsh harrier (Circus aeruginosus L. as refuges of potentially phytopathogenic and zoopathogenic fungi

Directory of Open Access Journals (Sweden)

Teresa Kornillowicz-Kowalska

2018-01-01

Full Text Available Birds’ nests may be refuges for various species of fungi including that which are potentially phytopathogenic and zoopathogenic. Among the 2449 isolates of fungi obtained from nests of Marsh harriers 96.8% belonged to filamentous fungi. In total, 37 genera were identified from 63 fungi species. Within the mycobiotas of the examined nests populations of fungi which are potentially pathogenic for humans, homoiothermous animals and plants dominated. Among 63 species, 46 (72% were potentially pathogenic fungi of which 18 species were potentially phytopathogenic and 32 species were pathogenic for homoiothermous animals. Inter alia species of fungi were found in the Marsh harriers nests: Aspergillus fumigatus, Aspergillus flavus, Scopulariopsis brevicaulis, Chrysosporium keratinophilum and Fusarium poae, Fusarium sporotrichioides. In terms of numbers, dominant in Marsh harrier nests were fungi pathogenic to birds, other homoiothermous animals and humans. On that basis it was concluded that Marsh harrier nests are both a source of fungal infections for that species and one of the links in the epidemiological cycle of opportunistic fungi for humans.

Nests of Marsh harrier (Circus aeruginosus L.) as refuges of potentially phytopathogenic and zoopathogenic fungi.

Science.gov (United States)

Kornillowicz-Kowalska, Teresa; Kitowski, Ignacy

2018-01-01

Birds' nests may be refuges for various species of fungi including that which are potentially phytopathogenic and zoopathogenic. Among the 2449 isolates of fungi obtained from nests of Marsh harriers 96.8% belonged to filamentous fungi. In total, 37 genera were identified from 63 fungi species. Within the mycobiotas of the examined nests populations of fungi which are potentially pathogenic for humans, homoiothermous animals and plants dominated. Among 63 species, 46 (72%) were potentially pathogenic fungi of which 18 species were potentially phytopathogenic and 32 species were pathogenic for homoiothermous animals. Inter alia species of fungi were found in the Marsh harriers nests: Aspergillus fumigatus , Aspergillus flavus , Scopulariopsis brevicaulis , Chrysosporium keratinophilum and Fusarium poae , Fusarium sporotrichioides . In terms of numbers, dominant in Marsh harrier nests were fungi pathogenic to birds, other homoiothermous animals and humans. On that basis it was concluded that Marsh harrier nests are both a source of fungal infections for that species and one of the links in the epidemiological cycle of opportunistic fungi for humans.

Genomic DNA extraction and barcoding of endophytic fungi.

Science.gov (United States)

Diaz, Patricia L; Hennell, James R; Sucher, Nikolaus J

2012-01-01

Endophytes live inter- and/or intracellularly inside healthy aboveground tissues of plants without causing disease. Endophytic fungi are found in virtually every vascular plant species examined. The origins of this symbiotic relationship between endophytes go back to the emergence of vascular plants. Endophytic fungi receive nutrition and protection from their hosts while the plants benefit from the production of fungal secondary metabolites, which enhance the host plants' resistance to herbivores, pathogens, and various abiotic stresses. Endophytic fungi have attracted increased interest as potential sources of secondary metabolites with agricultural, industrial, and medicinal use. This chapter provides detailed protocols for isolation of genomic DNA from fungal endophytes and its use in polymerase chain reaction-based amplification of the internal transcribed spacer region between the conserved flanking regions of the small and large subunit of ribosomal RNA for barcoding purposes.

Long-term cryopreservation of non-spore-forming fungi in Microbank™ beads for plant pathological investigations.

Science.gov (United States)

Lakshman, Dilip K; Singh, Vimla; Camacho, Manuel E

2018-05-01

Long-term preservation of experimental fungi without genetic, morphological, and pathogenic changes is of paramount importance in mycological and plant pathological investigations. Several cryogenic and non-cryogenic methods are available for the preservation of fungi, but the methods can be cumbersome, hazardous, expensive, and often not suitable for long-term storage of non-spore-forming (sterile) fungi. A method of preservation of spore-forming fungi in commercially available porous beads (Micrbank™) under cryogenic condition was successfully tested for three non-spore-forming basidiomycetes genera: Rhizoctonia solani (teleomorph: Thanatephorus cucumeris) (n = 19), Ceratobasidium species (n = 1), and Waitea circinata (n = 3), and a non-spore forming ascomycetes, Sclerotinia sclerotiorum (n = 1). For comparison, spore-forming ascomycetous fungi, Alternaria alternata (n = 1), Bauveria basiana (n = 2), Botrytis cinerea (n = 1), Fusarium oxysporum f.sp. gladiolii (n = 1), Trichoderma spp. (n = 3), and Thielaviopsis basicola (n = 2) were also cryopreserved in Microbank beads. Viable fungal isolates of all test species were retrieved after five years of storage at -80 °C, which was longer than the viabilities of the corresponding isolates cryopreserved in agar plugs or colonized wheat seeds. Fungi revived from the Microbank beads maintained identical morphology and cultural characteristics of the parent isolates. Randomly selected Rhizoctonia isolates revived from the Microbank beads maintained respective pathological properties of the parent isolates; also, no mutation was detected in the internal transcribed spacer (ITS) ribosomal DNA when compared with respective cultures maintained at ambient temperature. This finding demonstrated the utility of cryopreservation in Microbank beads as a convenient alternative to conventional long-term preservation of a wide group of fungal cultures for plant pathological investigations

Emission of bacteria and fungi in the air from wastewater treatment plants - a review.

Science.gov (United States)

Korzeniewska, Ewa

2011-01-01

An increase in global population, coupled with intensive development of industry and agriculture, has resulted in the generation and accumulation of large amounts of waste around the world. The spread of pathogenic microorganisms, endotoxins, odours and dust particles in the air is an inevitable consequence of waste production and waste management. Thus, the risk of infections associated with wastewater treatment plants (WWTPs) has become of a particular importance in recent decades. Sewage and unstable sludge contain various pathogens such as viruses, bacteria, and human and animal parasites. These microorganisms can be transmitted to the ambient air in wastewater droplets, which are generated during aeration or mechanical moving of the sewage. Bioaerosols generated during wastewater treatment may therefore pose a potential health hazard to workers of these plants or to habitants of their surroundings. The degree of human exposure to airborne bacteria, fungi, endotoxin and other allergens may vary significantly depending upon the type and the capacity of a plant, kind of the facilities, performed activities and meteorological conditions.

Soil eukaryotic microorganism succession as affected by continuous cropping of peanut--pathogenic and beneficial fungi were selected.

Directory of Open Access Journals (Sweden)

Mingna Chen

Full Text Available Peanut is an important oil crop worldwide and shows considerable adaptability but growth and yield are negatively affected by continuous cropping. Soil micro-organisms are efficient bio-indicators of soil quality and plant health and are critical to the sustainability of soil-based ecosystem function and to successful plant growth. In this study, 18S rRNA gene clone library analyses were employed to study the succession progress of soil eukaryotic micro-organisms under continuous peanut cultivation. Eight libraries were constructed for peanut over three continuous cropping cycles and its representative growth stages. Cluster analyses indicated that soil micro-eukaryotic assemblages obtained from the same peanut cropping cycle were similar, regardless of growth period. Six eukaryotic groups were found and fungi predominated in all libraries. The fungal populations showed significant dynamic change and overall diversity increased over time under continuous peanut cropping. The abundance and/or diversity of clones affiliated with Eurotiales, Hypocreales, Glomerales, Orbiliales, Mucorales and Tremellales showed an increasing trend with continuous cropping but clones affiliated with Agaricales, Cantharellales, Pezizales and Pyxidiophorales decreased in abundance and/or diversity over time. The current data, along with data from previous studies, demonstrated that the soil microbial community was affected by continuous cropping, in particular, the pathogenic and beneficial fungi that were positively selected over time, which is commonplace in agro-ecosystems. The trend towards an increase in fungal pathogens and simplification of the beneficial fungal community could be important factors contributing to the decline in peanut growth and yield over many years of continuous cropping.

Importance of seed-borne fungi of sorghum and pearl millet in Burkina Faso and their control using plant extracts

DEFF Research Database (Denmark)

Zida, Elisabeth Pawindé; Sérémé, Paco; Leth, Vibeke

2008-01-01

recorded on each crop by the blotter test. Six essential oils of plants were investigated for their inhibitory activity against eight pathogenic fungi. Thirty four and 27 fungal species were found in seed samples of sorghum and pearl millet, respectively. Phoma sp. and Fusarium moniliforme infected 95...... of pearl millet, respectively. Seeds inoculated with Acremonium strictum, Curvularia oryzae, F. equiseti, F. moniliforme and F. subglutinans and sown in sterilized soil, showed considerable mortality of the seedlings. Three essential oils inhibited in vitro the mycelial growth of all the fungi used by 85......Seed-borne fungi of sorghum and pearl millet in Burkina Faso were surveyed. A total of 188 seed samples from various locations, collected in 1989 (42) and 2002 (146), were tested, using the blotter, dry inspection and washing methods. Infection experiments were carried out with the major fungi...

Diversity of endophytic fungi in Glycine max.

Science.gov (United States)

Fernandes, Elio Gomes; Pereira, Olinto Liparini; da Silva, Cynthia Cânedo; Bento, Claudia Braga Pereira; de Queiroz, Marisa Vieira

2015-12-01

Endophytic fungi are microorganisms that live within plant tissues without causing disease during part of their life cycle. With the isolation and identification of these fungi, new species are being discovered, and ecological relationships with their hosts have also been studied. In Glycine max, limited studies have investigated the isolation and distribution of endophytic fungi throughout leaves and roots. The distribution of these fungi in various plant organs differs in diversity and abundance, even when analyzed using molecular techniques that can evaluate fungal communities in different parts of the plants, such as denaturing gradient gel electrophoresis (DGGE). Our results show there is greater species richness of culturable endophytic filamentous fungi in the leaves G. max as compared to roots. Additionally, the leaves had high values for diversity indices, i.e. Simpsons, Shannon and Equitability. Conversely, dominance index was higher in roots as compared to leaves. The fungi Ampelomyces sp., Cladosporium cladosporioides, Colletotrichum gloeosporioides, Diaporthe helianthi, Guignardia mangiferae and Phoma sp. were more frequently isolated from the leaves, whereas the fungi Fusarium oxysporum, Fusarium solani and Fusarium sp. were prevalent in the roots. However, by evaluating the two communities by DGGE, we concluded that the species richness was higher in the roots than in the leaves. UPGMA analysis showed consistent clustering of isolates; however, the fungus Leptospora rubella, which belongs to the order Dothideales, was grouped among species of the order Pleosporales. The presence of endophytic Fusarium species in G. max roots is unsurprising, since Fusarium spp. isolates have been previously described as endophyte in other reports. However, it remains to be determined whether the G. max Fusarium endophytes are latent pathogens or non-pathogenic forms that benefit the plant. This study provides a broader knowledge of the distribution of the fungal

The genomic organization of plant pathogenicity in Fusarium species

NARCIS (Netherlands)

Rep, M.; Kistler, H.C.

2010-01-01

Comparative genomics is a powerful tool to infer the molecular basis of fungal pathogenicity and its evolution by identifying differences in gene content and genomic organization between fungi with different hosts or modes of infection. Through comparative analysis, pathogenicity-related chromosomes

Induced mutation and somatic recombination as tools for genetic analysis and breeding of imperfect fungi

NARCIS (Netherlands)

Bos, C.J.

1986-01-01

Many fungi which are important in Agriculture as plant pathogens or in Biotechnology as producers of organic acids, antibiotics or enzymes, are imperfect fungi. These fungi do not have a sexual stage, which implies that they lack a meiotic recombination mechanism.

However, many

Using hierarchical clustering of secreted protein families to classify and rank candidate effectors of rust fungi.

Directory of Open Access Journals (Sweden)

Diane G O Saunders

Full Text Available Rust fungi are obligate biotrophic pathogens that cause considerable damage on crop plants. Puccinia graminis f. sp. tritici, the causal agent of wheat stem rust, and Melampsora larici-populina, the poplar leaf rust pathogen, have strong deleterious impacts on wheat and poplar wood production, respectively. Filamentous pathogens such as rust fungi secrete molecules called disease effectors that act as modulators of host cell physiology and can suppress or trigger host immunity. Current knowledge on effectors from other filamentous plant pathogens can be exploited for the characterisation of effectors in the genome of recently sequenced rust fungi. We designed a comprehensive in silico analysis pipeline to identify the putative effector repertoire from the genome of two plant pathogenic rust fungi. The pipeline is based on the observation that known effector proteins from filamentous pathogens have at least one of the following properties: (i contain a secretion signal, (ii are encoded by in planta induced genes, (iii have similarity to haustorial proteins, (iv are small and cysteine rich, (v contain a known effector motif or a nuclear localization signal, (vi are encoded by genes with long intergenic regions, (vii contain internal repeats, and (viii do not contain PFAM domains, except those associated with pathogenicity. We used Markov clustering and hierarchical clustering to classify protein families of rust pathogens and rank them according to their likelihood of being effectors. Using this approach, we identified eight families of candidate effectors that we consider of high value for functional characterization. This study revealed a diverse set of candidate effectors, including families of haustorial expressed secreted proteins and small cysteine-rich proteins. This comprehensive classification of candidate effectors from these devastating rust pathogens is an initial step towards probing plant germplasm for novel resistance components.

Mysterious Mycorrhizae? A Field Trip & Classroom Experiment to Demystify the Symbioses Formed between Plants & Fungi

Science.gov (United States)

Johnson, Nancy C.; Chaudhary, V. Bala; Hoeksema, Jason D.; Moore, John C.; Pringle, Anne; Umbanhowar, James A.; Wilson, Gail W. T.

2009-01-01

Biology curricula cover fungi in units on bacteria, protists, and primitive plants, but fungi are more closely related to animals than to bacteria or plants. Like animals, fungi are heterotrophs and cannot create their own food; but, like plants, fungi have cell walls, and are for the most part immobile. Most species of fungi have a filamentous…

Contribution to the knowledge of pathogenic fungi of spiders in Argentina. Southernmost record in the world.

Science.gov (United States)

Manfrino, Romina G; González, Alda; Barneche, Jorge; Tornesello Galván, Julieta; Hywell-Jones, Nigel; López Lastra, Claudia C

The aim of this study was to identify entomopathogenic fungi infecting spiders (Araneae) in a protected area of Buenos Aires province, Argentina. The Araneae species identified was Stenoterommata platensis. The pathogens identified were Lecanicillium aphanocladii Zare & W. Gams, Purpureocillium lilacinum (Thom) Luangsa-ard, Houbraken, Hywel Jones & Samson and Ophiocordyceps caloceroides (Berk & M.A. Curtis). This study constitutes the southernmost records in the world and contributes to expanding the knowledge of the biodiversity of pathogenic fungi of spiders in Argentina. Copyright © 2016 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

Genomic Encyclopedia of Fungi

Energy Technology Data Exchange (ETDEWEB)

Grigoriev, Igor

2012-08-10

Genomes of fungi relevant to energy and environment 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 150 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.

Multigene phylogeny and taxonomic revision of yeasts and related fungi in the Ustilaginomycotina

NARCIS (Netherlands)

Wang, Q. -M.; Begerow, D.; Groenewald, M.; Liu, X. -Z.; Theelen, B.; Bai, F. -Y.; Boekhout, T.

The subphylum Ustilaginomycotina (Basidiomycota, Fungi) comprises mainly plant pathogenic fungi (smuts). Some of the lineages possess cultivable unicellular stages that are usually classified as yeast or yeast-like species in a largely artificial taxonomic system which is independent from and

Fungi isolated from the rhizosphere of spring cruciferous plants

Directory of Open Access Journals (Sweden)

Barbara Majchrzak

2013-12-01

Full Text Available Fungal communities isolated from the rhizosphere of spring cruciferous plants were analysed in the study. It was found that the rhizosphere of crucifers was colonized primarily by fungi of the order Mucorales and of the genus Fusarium. Members of the genus Fusarium dominated in the rhizoplane. The roots of cruciferous plants secrete glucosinolates – secondary metabolites known for their antifungal properties, thus affecting the communities of soil-dwelling fungi.

Fungal Production and Manipulation of Plant Hormones.

Science.gov (United States)

Fonseca, Sandra; Radhakrishnan, Dhanya; Prasad, Kalika; Chini, Andrea

2018-01-01

Living organisms are part of a highly interconnected web of interactions, characterised by species nurturing, competing, parasitizing and preying on one another. Plants have evolved cooperative as well as defensive strategies to interact with neighbour organisms. Among these, the plant-fungus associations are very diverse, ranging from pathogenic to mutualistic. Our current knowledge of plant-fungus interactions suggests a sophisticated coevolution to ensure dynamic plant responses to evolving fungal mutualistic/pathogenic strategies. The plant-fungus communication relies on a rich chemical language. To manipulate the plant defence mechanisms, fungi produce and secrete several classes of biomolecules, whose modeof- action is largely unknown. Upon perception of the fungi, plants produce phytohormones and a battery of secondary metabolites that serve as defence mechanism against invaders or to promote mutualistic associations. These mutualistic chemical signals can be co-opted by pathogenic fungi for their own benefit. Among the plant molecules regulating plant-fungus interaction, phytohormones play a critical role since they modulate various aspects of plant development, defences and stress responses. Intriguingly, fungi can also produce phytohormones, although the actual role of fungalproduced phytohormones in plant-fungus interactions is poorly understood. Here, we discuss the recent advances in fungal production of phytohormone, their putative role as endogenous fungal signals and how fungi manipulate plant hormone balance to their benefits. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Secondary metabolites in fungus-plant interactions

Science.gov (United States)

Pusztahelyi, Tünde; Holb, Imre J.; Pócsi, István

2015-01-01

Fungi and plants are rich sources of thousands of secondary metabolites. The genetically coded possibilities for secondary metabolite production, the stimuli of the production, and the special phytotoxins basically determine the microscopic fungi-host plant interactions and the pathogenic lifestyle of fungi. The review introduces plant secondary metabolites usually with antifungal effect as well as the importance of signaling molecules in induced systemic resistance and systemic acquired resistance processes. The review also concerns the mimicking of plant effector molecules like auxins, gibberellins and abscisic acid by fungal secondary metabolites that modulate plant growth or even can subvert the plant defense responses such as programmed cell death to gain nutrients for fungal growth and colonization. It also looks through the special secondary metabolite production and host selective toxins of some significant fungal pathogens and the plant response in form of phytoalexin production. New results coming from genome and transcriptional analyses in context of selected fungal pathogens and their hosts are also discussed. PMID:26300892

Filamentous Growth in Eremothecium Fungi

DEFF Research Database (Denmark)

Oskarsson, Therese

, this thesis deals with some of the aspects of hyphal growth, which is an important virulence factor for pathogenic fungi infecting both humans and plants. Hyphal establishment through continuous polar growth is a complex process, requiring the careful coordination of a large subset of proteins involved......-regulatory activity of AgGts1, the protein could have additional actin organizing properties. In the second and third part, this thesis addresses the use of A. gossypii and its relative E. cymbalariae as model organisms for filamentous growth. A series of assays analyzed the capability of Eremothecium genus fungi...... of molecular tools for E. cymbalariae to enable a faster and more efficient approach for genetic comparisons between Eremothecium genus fungi....

Fungi isolated from Stewartia pseudocamellia Max. seeds and their pathogenesis

Directory of Open Access Journals (Sweden)

Halina Kurzawińska

2012-12-01

Full Text Available The aim of studies was to determine typical composition of fungi occurring on seeds of Stewartia pseudocamellia.The studies conducted on 100 disinfected and 100 nondisinfected seeds of these plants.Isolates of Alternaria alternata, Fusarium oxysporum, Cylindrocarpon radicicola and Rhizoctonia solani were characterized by pathogenicity towards the investigated Stewartia pseudocamellia. In the laboratory experiment, 204 isolations of microorganisms were obtained that belonged to 20 species and form of fungi and bacteria. Among fungi there were both of parasite (Alternaria alternata, Botrytis cinerea, Fusarium spp., Rhizoctonia solani and typical saprophytic (Cladosporium spp., Penicillium spp., Aspergillus spp., Epicoccum spp., Mucor spp.. The dominant fungus on seeds was Alternaria alternata. Among the investigated isolates only one isolate (R4 Rhizoctonia solani, was strongly pathogenic, isolates (A1 Alternaria alternata were weakly pathogenic to seedlings of Stewartia pseudocamellia.

Histone deacetylases: revealing the molecular base of dimorphism in pathogenic fungi

Directory of Open Access Journals (Sweden)

Alberto Elías-Villalobos

2015-11-01

Full Text Available Fungi, as every living organism, interact with the external world and have to adapt to its fluctuations. For pathogenic fungi, such interaction involves adapting to the hostile environment of their host. Survival depends on the capacity of fungi to detect and respond to external stimuli, which is achieved through a tight and efficient genetic control. Chromatin modifications represent a well-known layer of regulation that controls gene expression in response to environmental signals. However, less is known about the chromatin modifications that are involved in fungal virulence and the specific cues and signalling pathways that target chromatin modifications to specific genes. In a recently published study, our research group identified one such regulatory pathway. We demonstrated that the histone deacetylase (HDAC Hos2 is involved in yeast-to-hyphal transition (dimorphism and it is associated with the virulence of the maize pathogen Ustilago maydis, the causative agent of smut disease in corn. Hos2 activates mating-type genes by directly binding to their gene bodies. Furthermore, Hos2 acts downstream of the nutrient-sensing cyclic AMP-Protein Kinase A pathway. We also found that another HDAC, Clr3, contributes to this regulation, possibly in cooperation with Hos2. As a whole, our data suggest that there is a direct link between changes in the environment and acetylation of nucleosomes within certain genes. We propose that histone acetylation is critical to the proper timing and induction of transcription of the genes encoding factors that coordinate changes in morphology with pathogenesis.

Friends or foes? Emerging insights from fungal interactions with plants.

Science.gov (United States)

Zeilinger, Susanne; Gupta, Vijai K; Dahms, Tanya E S; Silva, Roberto N; Singh, Harikesh B; Upadhyay, Ram S; Gomes, Eriston Vieira; Tsui, Clement Kin-Ming; Nayak S, Chandra

2016-03-01

Fungi interact with plants in various ways, with each interaction giving rise to different alterations in both partners. While fungal pathogens have detrimental effects on plant physiology, mutualistic fungi augment host defence responses to pathogens and/or improve plant nutrient uptake. Tropic growth towards plant roots or stomata, mediated by chemical and topographical signals, has been described for several fungi, with evidence of species-specific signals and sensing mechanisms. Fungal partners secrete bioactive molecules such as small peptide effectors, enzymes and secondary metabolites which facilitate colonization and contribute to both symbiotic and pathogenic relationships. There has been tremendous advancement in fungal molecular biology, omics sciences and microscopy in recent years, opening up new possibilities for the identification of key molecular mechanisms in plant-fungal interactions, the power of which is often borne out in their combination. Our fragmentary knowledge on the interactions between plants and fungi must be made whole to understand the potential of fungi in preventing plant diseases, improving plant productivity and understanding ecosystem stability. Here, we review innovative methods and the associated new insights into plant-fungal interactions. © FEMS 2015.

Microbial pathogens in source and treated waters from drinking water treatment plants in the United States and implications for human health

Science.gov (United States)

An occurrence survey was conducted on selected pathogens in source and treated drinking water collected from 25 drinking water treatment plants (DWTPs) in the United States. Water samples were analyzed for the protozoa Giardia and Cryptosporidium (EPA Method 1623); the fungi Aspe...

Linking plants, fungi and soil mechanics

Science.gov (United States)

Yildiz, Anil; Graf, Frank

2017-04-01

Plants provide important functions in respect soil strength and are increasingly considered for slope stabilisation within eco-engineering methods, particularly to prevent superficial soil failure. The protective functions include hydrological regulation through interception and evapo-transpiration as well as mechanical stabilisation through root reinforcement and, to a certain extent, chemical stabilisation through sticky metabolites. The ever-growing application of plants in slope stabilisation demanded more precise information of the vegetation effects and, concomitant, led the models for quantifying the reinforcement shoot up like mushrooms. However, so far, the framework and interrelationships for both the role of plants and the quantification concepts have not been thoroughly analysed and comprehensively considered, respectively, often resulting in unsatisfactory results. Although it seems obvious and is implicitly presupposed that the plant specific functions related to slope stability require growth and development, this is anything but given, particularly under the often hostile conditions dominating on bare and steep slopes. There, the superficial soil layer is often characterised by a lack of fines and missing medium-sized and fine pores due to an unstable soil matrix, predominantly formed by coarse grains. Low water retention capacity and substantial leaching of nutrients are the adverse consequences. Given this general set-up, sustainable plant growth and, particularly, root development is virtually unachievable. At exactly this point mycorrhizal fungi, the symbiotic partners of almost all plants used in eco-engineering, come into play. Though, they are probably well-known within the eco-engineering community, mycorrhizal fungi lead a humble existence. This is in spite of the fact that they supply their hosts with water and nutrients, improving the plant's ability to master otherwise unbridgeable environmental conditions. However, in order to support

Membrane microdomains, rafts, and detergent-resistant membranes in plants and fungi.

Science.gov (United States)

Malinsky, Jan; Opekarová, Miroslava; Grossmann, Guido; Tanner, Widmar

2013-01-01

The existence of specialized microdomains in plasma membranes, postulated for almost 25 years, has been popularized by the concept of lipid or membrane rafts. The idea that detergent-resistant membranes are equivalent to lipid rafts, which was generally abandoned after a decade of vigorous data accumulation, contributed to intense discussions about the validity of the raft concept. The existence of membrane microdomains, meanwhile, has been verified by unequivocal independent evidence. This review summarizes the current state of research in plants and fungi with respect to common aspects of both kingdoms. In these organisms, principally immobile microdomains large enough for microscopic detection have been visualized. These microdomains are found in the context of cell-cell interactions (plant symbionts and pathogens), membrane transport, stress, and polarized growth, and the data corroborate at least three mechanisms of formation. As documented in this review, modern methods of visualization of lateral membrane compartments are also able to uncover the functional relevance of membrane microdomains.

Biology of flower-infecting fungi.

Science.gov (United States)

Ngugi, Henry K; Scherm, Harald

2006-01-01

The ability to infect host flowers offers important ecological benefits to plant-parasitic fungi; not surprisingly, therefore, numerous fungal species from a wide range of taxonomic groups have adopted a life style that involves flower infection. Although flower-infecting fungi are very diverse, they can be classified readily into three major groups: opportunistic, unspecialized pathogens causing necrotic symptoms such as blossom blights (group 1), and specialist flower pathogens which infect inflorescences either through the gynoecium (group 2) or systemically through the apical meristem (group 3). This three-tier system is supported by life history attributes such as host range, mode of spore transmission, degree of host sterilization as a result of infection, and whether or not the fungus undergoes an obligate sexual cycle, produces resting spores in affected inflorescences, and is r- or K-selected. Across the three groups, the flower as an infection court poses important challenges for disease management. Ecologically and evolutionarily, terms and concepts borrowed from the study of venereal (sexually transmitted) diseases of animals do not adequately capture the range of strategies employed by fungi that infect flowers.

An efficient method for DNA extraction from Cladosporioid fungi

OpenAIRE

Moslem, M.A.; Bahkali, A.H.; Abd-Elsalam, K.A.; Wit, de, P.J.G.M.

2010-01-01

We developed an efficient method for DNA extraction from Cladosporioid fungi, which are important fungal plant pathogens. The cell wall of Cladosporioid fungi is often melanized, which makes it difficult to extract DNA from their cells. In order to overcome this we grew these fungi for three days on agar plates and extracted DNA from mycelium mats after manual or electric homogenization. High-quality DNA was isolated, with an A260/A280 ratio ranging between 1.6 and 2.0. Isolated genomic DNA w...

Antifungal Activity of Tamarix aphylla (L. Karst. Stem-bark Extract Against Some Pathogenic Fungi

Directory of Open Access Journals (Sweden)

Sadaf bibi bibi

2015-03-01

Full Text Available The largest identified, Tamarix aphylla (L. Karst. belonging to family Tamaricaceae is traditionally an important plant used to cure various ailments. Three concentrations of crude ethanolic extracts 2000 ppm, 1000 ppm and 500 ppm were tested against six pathogenic fungi: Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, Fusarium oxysporum, Penicillium notatum and Saccharomyces cerevisiae using five different solvents: acetone, chloroform, distilled water (DW, ethanol and methanol. Percent inhibition in growth of fungi was found to be dose dependent. The standard antifungal synthetic drug, Terbinafine, was used in different concentrations mixed with distilled water against different test fungi. Terbinafine completely controlled the growth of A. flavus, A. fumigatus, A. niger, F. oxysporum, P. notatum and S. cerevisiae with the concentrations of 65±0.58, 72±1.00, 70±1.15, 59±1.00, 60±0.58 and 80±0.58 (µg/ml of PDA medium, respectively. Chloroform was considered to be the most effective solvent preventing 97.68±0.58% growth of F. oxysporum, 9.37±0.33% in A. niger, 92.68±3.33% in S. cerevisiae, 91.46±2.08% in A. fumigatus, 88.48±0.88% in A. flavus and 87.95±1.15% in P. notatum. Statistically, the results were compared with negative control and most of the results were found to be highly significant (p≤0.000. Overall, our results suggest that T. aphylla stem-bark extract illustrated maximum percent inhibition with chloroform followed by ethanol, acetone, methanol and distilled water.

The cuticle and plant defense to pathogens

Directory of Open Access Journals (Sweden)

Jean-Pierre eMetraux

2014-06-01

Full Text Available The cuticle provides a physical barrier against water loss and protects against irradiation, xenobiotics and pathogens. Components of the cuticle are perceived by invading fungi and activate developmental processes during pathogenesis. In addition, cuticle alterations of various types induce a syndrome of reactions that often results in resistance to necrotrophs. This article reviews the current knowledge on the role of the cuticle in relation to the perception of pathogens and activation of defenses.

Stepwise screening of microorganisms for commercial use in biological control of plant pathogenic fungi and bacteria. Biological Control

NARCIS (Netherlands)

Köhl, J.; Postma, J.; Nicot, P.; Ruocco, M.

2011-01-01

The development of new biocontrol products against plant diseases requires screening of high numbers of candidate antagonists. Antagonists for commercial use have to fulfill many different requirements. Besides being active against the specific targeted plant pathogens they must be safe and

Human Pathogens on Plants: Designing a Multidisciplinary Strategy for Research.

Science.gov (United States)

Fletcher, Jacqueline; Leach, Jan E; Eversole, Kellye; Tauxe, Robert

2014-10-15

Recent efforts to address concerns about microbial contamination of food plants and resulting foodborne illness have prompted new collaboration and interactions between the scientific communities of plant pathology and food safety. This article provides perspectives from scientists of both disciplines and presents selected research results and concepts that highlight existing and possible future synergisms for audiences of both disciplines. Plant pathology is a complex discipline that encompasses studies of the dissemination, colonization, and infection of plants by microbes such as bacteria, viruses, fungi, and oomycetes. Plant pathologists study plant diseases as well as host plant defense responses and disease management strategies with the goal of minimizing disease occurrences and impacts. Repeated outbreaks of human illness attributed to the contamination of fresh produce, nuts and seeds, and other plant-derived foods by human enteric pathogens such as Shiga toxin-producing Escherichia coli and Salmonella spp. have led some plant pathologists to broaden the application of their science in the past two decades, to address problems of human pathogens on plants (HPOPs). Food microbiology, which began with the study of microbes that spoil foods and those that are critical to produce food, now also focuses study on how foods become contaminated with pathogens and how this can be controlled or prevented. Thus, at the same time, public health researchers and food microbiologists have become more concerned about plant-microbe interactions before and after harvest. New collaborations are forming between members of the plant pathology and food safety communities, leading to enhanced research capacity and greater understanding of the issues for which research is needed. The two communities use somewhat different vocabularies and conceptual models. For example, traditional plant pathology concepts such as the disease triangle and the disease cycle can help to define

Human pathogens on plants: designing a multidisciplinary strategy for research.

Science.gov (United States)

Fletcher, Jacqueline; Leach, Jan E; Eversole, Kellye; Tauxe, Robert

2013-04-01

Recent efforts to address concerns about microbial contamination of food plants and resulting foodborne illness have prompted new collaboration and interactions between the scientific communities of plant pathology and food safety. This article provides perspectives from scientists of both disciplines and presents selected research results and concepts that highlight existing and possible future synergisms for audiences of both disciplines. Plant pathology is a complex discipline that encompasses studies of the dissemination, colonization, and infection of plants by microbes such as bacteria, viruses, fungi, and oomycetes. Plant pathologists study plant diseases as well as host plant defense responses and disease management strategies with the goal of minimizing disease occurrences and impacts. Repeated outbreaks of human illness attributed to the contamination of fresh produce, nuts and seeds, and other plant-derived foods by human enteric pathogens such as Shiga toxin-producing Escherichia coli and Salmonella spp. have led some plant pathologists to broaden the application of their science in the past two decades, to address problems of human pathogens on plants (HPOPs). Food microbiology, which began with the study of microbes that spoil foods and those that are critical to produce food, now also focuses study on how foods become contaminated with pathogens and how this can be controlled or prevented. Thus, at the same time, public health researchers and food microbiologists have become more concerned about plant-microbe interactions before and after harvest. New collaborations are forming between members of the plant pathology and food safety communities, leading to enhanced research capacity and greater understanding of the issues for which research is needed. The two communities use somewhat different vocabularies and conceptual models. For example, traditional plant pathology concepts such as the disease triangle and the disease cycle can help to define

Investigating the Antimicrobial Bioactivity of Cyano bacterial Extracts on Some Plant and Human Pathogens

International Nuclear Information System (INIS)

El-Semary, N.A.; Osman, M.E.; Ahmed, A.S.; Botros, H.W.; Farag, A.T.

2014-01-01

The search for broad spectrum antimicrobial agents against microbial pathogens, as the available bioactive compounds, has decreasing efficacy and the multidrug resistance trait is spreading among pathogens. Accordingly, the study was carried out to investigate the antimicrobial bioactivity of extracts derived from a cyano bacterial strain from Egypt. The solvents used were diethyl ether, chloroform and methanol. The antimicrobial bioassay of the lipophilic fraction dissolved in diethyl ether of Synechococcus spp. (isolated from Wadi El-Natroun, Egypt) showed the highest broad spectrum bioactivity as it inhibited the growth of both plant and human pathogens. The extract was also effective on the filamentous plant pathogenic fungi Aspergillus flavus and Aspergillus niger. The effects of incubation periods, growth media and pH values on both growth and antimicrobial activity of Synechococcus spp. were investigated. Chu medium was the medium that gave the highest growth followed by BG11 medium then Oscillatoria medium and all these three media showed antibacterial activities but only BG11 showed both antibacterial and antifungal activities after 18 days of incubation. The pH value 10 proved to be the best for growth and antimicrobial activities of Synechococcus spp. in BG11 medium

Mutualism and Antagonism: Ecological Interactions Among Bark Beetles, Mite and Fungi

Science.gov (United States)

K.D. Klepzig; J.C. Moser; M.J. Lombardero; M.P. Ayres; R.W. Hofstetter; C.J. Walkinshaw

2001-01-01

Insect-fungal complexes provide challenging and fascinating systems for the study of biotic interactions between plants. plant pathogens, insect vectors and other associated organisms. The types of interactions among these organisms (mutualism. antagonism. parasitism. phoresy. etc.) are as variable as the range of organisms involved (plants, fungi, insects. mites. etc...

A Friendly Relationship between Endophytic Fungi and Medicinal Plants: A Systematic Review

Science.gov (United States)

Jia, Min; Chen, Ling; Xin, Hai-Liang; Zheng, Cheng-Jian; Rahman, Khalid; Han, Ting; Qin, Lu-Ping

2016-01-01

Endophytic fungi or endophytes exist widely inside the healthy tissues of living plants, and are important components of plant micro-ecosystems. Over the long period of evolution, some co-existing endophytes and their host plants have established a special relationship with one and another, which can significantly influence the formation of metabolic products in plants, then affect quality and quantity of crude drugs derived from medicinal plants. This paper will focus on the increasing knowledge of relationships between endophytic fungi and medicinal plants through reviewing of published research data obtained from the last 30 years. The analytical results indicate that the distribution and population structure of endophytes can be considerably affected by factors, such as the genetic background, age, and environmental conditions of their hosts. On the other hand, the endophytic fungi can also confer profound impacts on their host plants by enhancing their growth, increasing their fitness, strengthening their tolerances to abiotic and biotic stresses, and promoting their accumulation of secondary metabolites. All the changes are very important for the production of bioactive components in their hosts. Hence, it is essential to understand such relationships between endophytic fungi and their host medicinal plants. Such knowledge can be well exploited and applied for the production of better and more drugs from medicinal plants. PMID:27375610

Entomopathogenic fungi on Hemiberlesia pitysophila.

Directory of Open Access Journals (Sweden)

Chengqun Lv

Full Text Available Hemiberlesia pitysophila Takagi is an extremely harmful exotic insect in forest to Pinus species, including Pinus massoniana. Using both morphological taxonomy and molecular phylogenetics, we identified 15 strains of entomogenous fungi, which belong to 9 genera with high diversities. Surprisingly, we found that five strains that were classified as species of Pestalotiopsis, which has been considered plant pathogens and endophytes, were the dominant entomopathogenic fungus of H. pitysophila. Molecular phylogenetic tree established by analyzing sequences of ribosomal DNA internal transcribed spacer showed that entomopathogenic Pestalotiopsis spp. were similar to plant Pestalotiopsis, but not to other pathogens and endophytes of its host plant P. massoniana. We were the first to isolate entomopathogenic Pestalotiopsis spp. from H. pitysophila. Our findings suggest a potential and promising method of H. pitysophila bio-control.

Entomopathogenic fungi on Hemiberlesia pitysophila.

Science.gov (United States)

Lv, Chengqun; Huang, Baoling; Qiao, Mengji; Wei, Jiguang; Ding, Bo

2011-01-01

Hemiberlesia pitysophila Takagi is an extremely harmful exotic insect in forest to Pinus species, including Pinus massoniana. Using both morphological taxonomy and molecular phylogenetics, we identified 15 strains of entomogenous fungi, which belong to 9 genera with high diversities. Surprisingly, we found that five strains that were classified as species of Pestalotiopsis, which has been considered plant pathogens and endophytes, were the dominant entomopathogenic fungus of H. pitysophila. Molecular phylogenetic tree established by analyzing sequences of ribosomal DNA internal transcribed spacer showed that entomopathogenic Pestalotiopsis spp. were similar to plant Pestalotiopsis, but not to other pathogens and endophytes of its host plant P. massoniana. We were the first to isolate entomopathogenic Pestalotiopsis spp. from H. pitysophila. Our findings suggest a potential and promising method of H. pitysophila bio-control.

Interaction intimacy of pathogens and herbivores with their host plants influences the topological structure of ecological networks in different ways.

Science.gov (United States)

Benítez-Malvido, Julieta; Dáttilo, Wesley

2015-04-01

• Over the past two decades an interest in the role that plant-animal mutualistic networks play in the organization and dynamic of biodiversity has steadily risen. Despite the ecological, evolutionary, and economic importance of plant-herbivore and plant-pathogen antagonistic relationships, however, few studies have examined these interactions in an ecological network framework.• We describe for the first time the topological structure of multitrophic networks involving congeneric tropical plant species of the genus Heliconia (Heliconiaceae, Zingiberales) and their herbivores and pathogens in the state of Pernambuco, Brazil. We based our study on the available literature describing the organisms (e.g., insects, mites, fungi, and bacteria) that attack 24 different species, hybrids, and cultivated varieties of Heliconia.• In general, pathogen- and herbivore-Heliconia networks differed in their topological structure (more modular vs. more nested, respectively): pathogen-Heliconia networks were more specialized and compartmentalized than herbivore-Heliconia networks. High modularity was likely due to the high intimacy that pathogens have with their host plants as compared with the more generalized feeding modes and behavior of herbivores. Some clusters clearly reflected the clustering of closely related cultivated varieties of Heliconia sharing the same pathogens.• From a commercial standpoint, different varieties of the same Heliconia species may be more susceptible to being attacked by the same species of pathogens. In summary, our study highlights the importance of interaction intimacy in structuring trophic relationships between plants and pathogens in the tropics. © 2015 Botanical Society of America, Inc.

Endophytic fungi associated with Monarda citriodora, an aromatic and medicinal plant and their biocontrol potential.

Science.gov (United States)

Katoch, Meenu; Pull, Shipra

2017-12-01

The Food and Agriculture Organization has estimated that every year considerable losses of the food crops occur due to plant diseases. Although fungicides are extensively used for management of plant diseases, they are expensive and hazardous to the environment and human health. Alternatively, biological control is the safe way to overcome the effects of plant diseases and to sustain agriculture. Since Monarda citriodora Cerv. ex Lag. (Lamiaceae/Labiatae) is known for its antifungal properties, it was chosen for the study. The isolation of endophytic fungi from M. citriodora and assessing their biocontrol potential. The isolated endophytes were characterized using ITS-5.8 S rDNA sequencing. Their biocontrol potential was assessed using different antagonistic assays against major plant pathogens. Twenty-eight endophytes representing 11 genera were isolated, of which, around 82% endophytes showed biocontrol potential against plant pathogens. MC-2 L (Fusarium oxysporum), MC-14 F (F. oxysporum), MC-22 F (F. oxysporum) and MC-25 F (F. redolens) displayed significant antagonistic activity against all the tested pathogens. Interestingly, MC-10 L (Muscodor yucatanensis) completely inhibited the growth of Sclerotinia sp., Colletotrichum capsici, Aspergillus flavus and A. fumigatus in dual culture assay, whereas MC-8 L (A. oryzae) and MC-9 L (Penicillium commune) completely inhibited the growth of the Sclerotinia sp. in fumigation assay. Endophytes MC-2 L, MC-14 F, MC-22 F and MC-25 F could effectively be used to control broad range of phytopathogens, while MC-10 L, MC-8 L and MC-9 L could be used to control specific pathogens. Secondly, endophytes showing varying degrees of antagonism in different assays represented the chemo-diversity not only as promising biocontrol agents but also as a resource of defensive and bioactive metabolites.

Swainsonine biosynthesis genes in diverse symbiotic and pathogenic fungi

Science.gov (United States)

Swainsonine, a cytotoxic fungal alkaloid and a potential cancer therapy drug, is produced by the insect pathogen and plant symbiont, Metarhizium robertsii, the clover pathogen Slafractonia leguminicola, locoweed symbionts belonging to Alternaria sect. Undifilum, and a recently discovered morning glo...

RNAi suppressors encoded by pathogenic human viruses

NARCIS (Netherlands)

de Vries, Walter; Berkhout, Ben

2008-01-01

RNA silencing or RNAi interference (RNAi) serves as an innate antiviral mechanism in plants, fungi and animals. Human viruses, like plant viruses, encode suppressor proteins or RNAs that block or modulate the RNAi pathway. This review summarizes the mechanisms by which pathogenic human viruses

Babaco (Vasconcellea heilbornii var. pentagona Badillo. Major plant pathogens and control strategies

Directory of Open Access Journals (Sweden)

Angel Rolando Robles-Carrión

2016-04-01

Full Text Available This work was carried out with the aim of documenting the importance of Babaco for the Andean region, its main plant pathogens, and possible control strategies and integrated management, emphasizing the MVB. Was performed a systematic review of scientific papers published in prestigious journals and thesis diplomas, masters and doctorates from various universities. As a criterion for inclusion-exclusion studies were taken into account in the genus Vasconcellea. Ecuador has 15 of the 21 described species, of which more than half are located in the province of Loja. Vascular Wilt Babaco (MVB is caused by a complex of Fusarium fungi that interact with the plant. There are no integrated management strategies for Vascular Wilt Babaco scientifically proven.

Biological control of dodder (Cuscuta campestris L. by fungi pathogens

Directory of Open Access Journals (Sweden)

F. Fallahpour

2016-04-01

Full Text Available Parasite weeds are the most important yield reducing factors, and among them dodder (Cuscuta campestris L. is an obligate parasite of many plant families. In order to find a suitable biocontrol agent for dodder a study was conducted based on a randomized complete design with four replications at research greenhouse of Faculty of Agriculture, Ferdowsi University of Mashhad, Iran during 2007-2009. Diseased dodders sampled from sugarbeet farms of Chenaran, Iran. After culturing and isolating exiting fungi from infected tissues of dodder, Fusarium sp., Alternaria sp. and Colletotrichum sp. were recognized. Inoculation of isolates was carried out with concenteration of 1×108 spores per ml sterile water at different growth stages of dodder in labratoary and greenhouse. Among different fungi, isolate of 323 of F. oxysporum showed an effective control on germination of dodder seeds and the highest level of plant pathogencity was before the contact of dodder with host and infection in older plants decreased. Infection of this isolate with crops such as sugarbeet (Beta vulgaris L., alfalfa (Medigago sativa L., basil (Ocimum basilicum L., wheat (Triticum aestivum L. and barley (Hordeum vulgare L. showed no symptoms.

[Discussion on appraisal methods and key technologies of arbuscular mycorrhizal fungi and medicinal plant symbiosis system].

Science.gov (United States)

Chen, Meilan; Guo, Lanping; Yang, Guang; Chen, Min; Yang, Li; Huang, Luqi

2011-11-01

Applications of arbuscular mycorrhizal fungi in research of medicinal plant cultivation are increased in recent years. Medicinal plants habitat is complicated and many inclusions are in root, however crop habitat is simple and few inclusions in root. So appraisal methods and key technologies about the symbiotic system of crop and arbuscular mycorrhizal fungi can't completely suitable for the symbiotic system of medicinal plants and arbuscular mycorrhizal fungi. This article discuss the appraisal methods and key technologies about the symbiotic system of medicinal plant and arbuscular mycorrhizal fungi from the isolation and identification of arbuscular mycorrhiza, and the appraisal of colonization intensity. This article provides guidance for application research of arbuscular mycorrhizal fungi in cultivation of medicinal plants.

The pathogenic fungi in mushroom cultivation of Agaricus bisporus (Lange.) Imbach.

OpenAIRE

Agata Tekiela

2012-01-01

The research was conducted in a mushroom growing facility located near Rzeszów, consisting of three production cycles. The number and composition of microorganisms which accompany the mushroom cultivation depended on the healthiness of: the compost, casing and spawn of Agaricus bisporus. The presence of pathogenic fungi in the cultivation halls at the beginning of the production cycle is a serious threat to the cultivation of common mushroom because their rapid development shortens the span o...

Control of grapevine wood fungi in commercial nurseries

Directory of Open Access Journals (Sweden)

C. Rego

2009-05-01

Full Text Available Previous surveys conducted in commercial nurseries found that different wood fungi, namely Cylindrocarpon spp., Botryosphaeriaceae, Phomopsis viticola and Phaeomoniella chlamydospora infect grapevine cuttings. Two field trials were carried out to evaluate the effectiveness of cyprodinil + fludioxonil, pyraclostrobin + metiram, fludioxonil and cyprodinil to prevent or reduce natural infections caused by such fungi. Rootstock and scion cuttings were soaked in fungicidal suspensions for 50 min prior to grafting. After callusing, the grafted cuttings were planted in two commercial field nurseries with and without a previous history of grapevine cultivation. After nine months in the nursery, the plants were uprooted and analysed for the incidence and severity of the wood fungi. Plants uprooted from the field without a previous history of grapevine cultivation were generally less strongly infected by wood fungi. Under this condition, only the mixture cyprodinil + fludioxonil simultaneously reduced the incidence of Cylindrocarpon and Botryosphaeriaceae fungi, as well as the severity of Cylindrocarpon infections. Treatments did not produce significant differences in the incidence and severity of P. viticola, and Pa. chlamydospora. For plants grown in the field with a grapevine history, all fungicides except cyprodinil significantly reduced the incidence and severity of Cylindrocarpon fungi. Also, the incidence and severity of Botryosphaeriaceae pathogens were significantly decreased both by cyprodinil + fludioxonil and by cyprodinil. No significant differences were noticed for P. viticola incidence and severity, and Pa. chlamydospora was not detected again. These results suggest that the practice of soaking grapevine cuttings in selected fungicides prior to grafting significantly reduces Cylindrocarpon spp. and Botryosphaeriaceae infections, thus improving the quality of planting material.

Differential Microbial Diversity in Drosophila melanogaster: Are Fruit Flies Potential Vectors of Opportunistic Pathogens?

Directory of Open Access Journals (Sweden)

Luis A. Ramírez-Camejo

2017-01-01

Full Text Available Drosophila melanogaster has become a model system to study interactions between innate immunity and microbial pathogens, yet many aspects regarding its microbial community and interactions with pathogens remain unclear. In this study wild D. melanogaster were collected from tropical fruits in Puerto Rico to test how the microbiota is distributed and to compare the culturable diversity of fungi and bacteria. Additionally, we investigated whether flies are potential vectors of human and plant pathogens. Eighteen species of fungi and twelve species of bacteria were isolated from wild flies. The most abundant microorganisms identified were the yeast Candida inconspicua and the bacterium Klebsiella sp. The yeast Issatchenkia hanoiensis was significantly more common internally than externally in flies. Species richness was higher in fungi than in bacteria, but diversity was lower in fungi than in bacteria. The microbial composition of flies was similar internally and externally. We identified a variety of opportunistic human and plant pathogens in flies such as Alcaligenes faecalis, Aspergillus flavus, A. fumigatus, A. niger, Fusarium equiseti/oxysporum, Geotrichum candidum, Klebsiella oxytoca, Microbacterium oxydans, and Stenotrophomonas maltophilia. Despite its utility as a model system, D. melanogaster can be a vector of microorganisms that represent a potential risk to plant and public health.

ECOTOXICITY AND PHYTOTOXICITY OF PLANT PROTECTION PRODUCTS TO RHIZOSPHERE FUNGI AND WINTER WHEAT SEEDLINGS

Directory of Open Access Journals (Sweden)

Anna Daria Stasiulewicz-Paluch

2015-11-01

Full Text Available Registration of plant protection products involves the analysis of their effects on soil microorganisms. The residues of plant protection products penetrate the soil, but their impact on fungi remains scarcely researched. In this study, the influence of selected plant protection products on the abundance of rhizosphere-dwelling fungi and the growth of winter wheat seedlings was evaluated under greenhouse conditions. The analysed plant protection products had an inhibitory effect on the growth of filamentous fungi in the rhizosphere, whereas yeasts were resistant to those products applied to soil. Tebuconazole exerted the strongest suppressive effect on the growth of filamentous fungi, and propiconazole was characterized by the greatest phytotoxic activity against winter wheat seedlings. Azoxystrobin had the weakest ecotoxic and phytotoxic effects, and its application to soil usually led to a rapid increase in the counts of fungi of the genus Acremonium.

[An example of research on biological control: Entomophthora fungi pathogenic for aphids].

Science.gov (United States)

Latgé, J P; Remaudière, G; Papierok, B

1978-01-01

The results obtained in 15 years of research on the Entomophthorales pathogen of aphids showed the importance of the action of these fungi in the regulation of natural aphid populations and their possible use in agriculture as a biological control agent. Recent ecological studies on natural populations of aphids established the seasonal variation of the different fungal species and the diverse degrees of specificity between the species or groups of species of aphid and the various species of Entomophthora. The study of populations dynamics of an aphid species on a cultivated plant permitted the determination of the way a certain number of biotic and abiotic factors, such as temperature, humidity, thresholds of the insect population and of the infecting fungus lead to an epizootic development. If the air propagation of the disease by conidia is understood for a long time, the role of the soil as a reservoir for the infecting fungus has been demonstrated recently. Under favourable climatic conditions, the use of industrially produced resistant resting spores would allow the regulation of aphid populations in nature.

Impact of arbuscular mycorrhizal fungi on uranium accumulation by plants

International Nuclear Information System (INIS)

Dupre de Boulois, H.; Joner, E.J.; Leyval, C.; Jakobsen, I.; Chen, B.D.; Roos, P.; Thiry, Y.; Rufyikiri, G.; Delvaux, B.; Declerck, S.

2008-01-01

Contamination by uranium (U) occurs principally at U mining and processing sites. Uranium can have tremendous environmental consequences, as it is highly toxic to a broad range of organisms and can be dispersed in both terrestrial and aquatic environments. Remediation strategies of U-contaminated soils have included physical and chemical procedures, which may be beneficial, but are costly and can lead to further environmental damage. Phytoremediation has been proposed as a promising alternative, which relies on the capacity of plants and their associated microorganisms to stabilize or extract contaminants from soils. In this paper, we review the role of a group of plant symbiotic fungi, i.e. arbuscular mycorrhizal fungi, which constitute an essential link between the soil and the roots. These fungi participate in U immobilization in soils and within plant roots and they can reduce root-to-shoot translocation of U. However, there is a need to evaluate these observations in terms of their importance for phytostabilization strategies

Plant innate immunity against human bacterial pathogens

Directory of Open Access Journals (Sweden)

Maeli eMelotto

2014-08-01

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

Plant-ants use symbiotic fungi as a food source: new insight into the nutritional ecology of ant-plant interactions.

Science.gov (United States)

Blatrix, Rumsaïs; Djiéto-Lordon, Champlain; Mondolot, Laurence; La Fisca, Philippe; Voglmayr, Hermann; McKey, Doyle

2012-10-07

Usually studied as pairwise interactions, mutualisms often involve networks of interacting species. Numerous tropical arboreal ants are specialist inhabitants of myrmecophytes (plants bearing domatia, i.e. hollow structures specialized to host ants) and are thought to rely almost exclusively on resources derived from the host plant. Recent studies, following up on century-old reports, have shown that fungi of the ascomycete order Chaetothyriales live in symbiosis with plant-ants within domatia. We tested the hypothesis that ants use domatia-inhabiting fungi as food in three ant-plant symbioses: Petalomyrmex phylax/Leonardoxa africana, Tetraponera aethiops/Barteria fistulosa and Pseudomyrmex penetrator/Tachigali sp. Labelling domatia fungal patches in the field with either a fluorescent dye or (15)N showed that larvae ingested domatia fungi. Furthermore, when the natural fungal patch was replaced with a piece of a (15)N-labelled pure culture of either of two Chaetothyriales strains isolated from T. aethiops colonies, these fungi were also consumed. These two fungi often co-occur in the same ant colony. Interestingly, T. aethiops workers and larvae ingested preferentially one of the two strains. Our results add a new piece in the puzzle of the nutritional ecology of plant-ants.

Plant-ants use symbiotic fungi as a food source: new insight into the nutritional ecology of ant–plant interactions

Science.gov (United States)

Blatrix, Rumsaïs; Djiéto-Lordon, Champlain; Mondolot, Laurence; La Fisca, Philippe; Voglmayr, Hermann; McKey, Doyle

2012-01-01

Usually studied as pairwise interactions, mutualisms often involve networks of interacting species. Numerous tropical arboreal ants are specialist inhabitants of myrmecophytes (plants bearing domatia, i.e. hollow structures specialized to host ants) and are thought to rely almost exclusively on resources derived from the host plant. Recent studies, following up on century-old reports, have shown that fungi of the ascomycete order Chaetothyriales live in symbiosis with plant-ants within domatia. We tested the hypothesis that ants use domatia-inhabiting fungi as food in three ant–plant symbioses: Petalomyrmex phylax/Leonardoxa africana, Tetraponera aethiops/Barteria fistulosa and Pseudomyrmex penetrator/Tachigali sp. Labelling domatia fungal patches in the field with either a fluorescent dye or 15N showed that larvae ingested domatia fungi. Furthermore, when the natural fungal patch was replaced with a piece of a 15N-labelled pure culture of either of two Chaetothyriales strains isolated from T. aethiops colonies, these fungi were also consumed. These two fungi often co-occur in the same ant colony. Interestingly, T. aethiops workers and larvae ingested preferentially one of the two strains. Our results add a new piece in the puzzle of the nutritional ecology of plant-ants. PMID:22859596

Immunity to plant pathogens and iron homeostasis.

Science.gov (United States)

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

2015-11-01

Iron is essential for metabolic processes in most living organisms. Pathogens and their hosts often compete for the acquisition of this nutrient. However, iron can catalyze the formation of deleterious reactive oxygen species. Hosts may use iron to increase local oxidative stress in defense responses against pathogens. Due to this duality, iron plays a complex role in plant-pathogen interactions. Plant defenses against pathogens and plant response to iron deficiency share several features, such as secretion of phenolic compounds, and use common hormone signaling pathways. Moreover, fine tuning of iron localization during infection involves genes coding iron transport and iron storage proteins, which have been shown to contribute to immunity. The influence of the plant iron status on the outcome of a given pathogen attack is strongly dependent on the nature of the pathogen infection strategy and on the host species. Microbial siderophores emerged as important factors as they have the ability to trigger plant defense responses. Depending on the plant species, siderophore perception can be mediated by their strong iron scavenging capacity or possibly via specific recognition as pathogen associated molecular patterns. This review highlights that iron has a key role in several plant-pathogen interactions by modulating immunity. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Seasonality of pathogenic fungi in mites of rubber tree plantations adjacent to fragments of Cerrado

Directory of Open Access Journals (Sweden)

PR. Demite

Full Text Available Fungi are the most frequently observed pathogens of mite populations, helping to control them on different crops. Twenty-five samples of leaves were collected from rubber tree plantations adjacent to two fragments of Cerrado vegetation. Each rubber tree plantation had 25 plants selected for sampling and seven leaves from around each tree top were collected up to seven to eight meters above ground. Approximately 250 individuals of Calacarus heveae Feres, Phyllocoptruta seringueirae Feres, and Tenuipalpus heveae Baker, collected randomly, were mounted from each plantation. Hirsutella thompsoni Fisher was observed on all three mites and T. heveae was the most infected species. The highest infestation levels occurred from November to February (rainy season. In the dry season, infestation levels were below 5%. Hirsutella thompsonii has potential to be used as mycoacaricide during the rainy season.

The pathogenic fungi in mushroom cultivation of Agaricus bisporus (Lange. Imbach.

Directory of Open Access Journals (Sweden)

Agata Tekiela

2012-12-01

Full Text Available The research was conducted in a mushroom growing facility located near Rzeszów, consisting of three production cycles. The number and composition of microorganisms which accompany the mushroom cultivation depended on the healthiness of: the compost, casing and spawn of Agaricus bisporus. The presence of pathogenic fungi in the cultivation halls at the beginning of the production cycle is a serious threat to the cultivation of common mushroom because their rapid development shortens the span of fruiting body harvests.

Phylogenomic analysis demonstrates a pattern of rare and ancient horizontal gene transfer between plants and fungi.

Science.gov (United States)

Richards, Thomas A; Soanes, Darren M; Foster, Peter G; Leonard, Guy; Thornton, Christopher R; Talbot, Nicholas J

2009-07-01

Horizontal gene transfer (HGT) describes the transmission of genetic material across species boundaries and is an important evolutionary phenomenon in the ancestry of many microbes. The role of HGT in plant evolutionary history is, however, largely unexplored. Here, we compare the genomes of six plant species with those of 159 prokaryotic and eukaryotic species and identify 1689 genes that show the highest similarity to corresponding genes from fungi. We constructed a phylogeny for all 1689 genes identified and all homolog groups available from the rice (Oryza sativa) genome (3177 gene families) and used these to define 14 candidate plant-fungi HGT events. Comprehensive phylogenetic analyses of these 14 data sets, using methods that account for site rate heterogeneity, demonstrated support for nine HGT events, demonstrating an infrequent pattern of HGT between plants and fungi. Five HGTs were fungi-to-plant transfers and four were plant-to-fungi HGTs. None of the fungal-to-plant HGTs involved angiosperm recipients. These results alter the current view of organismal barriers to HGT, suggesting that phagotrophy, the consumption of a whole cell by another, is not necessarily a prerequisite for HGT between eukaryotes. Putative functional annotation of the HGT candidate genes suggests that two fungi-to-plant transfers have added phenotypes important for life in a soil environment. Our study suggests that genetic exchange between plants and fungi is exceedingly rare, particularly among the angiosperms, but has occurred during their evolutionary history and added important metabolic traits to plant lineages.

Activity of the pterophyllins 2 and 4 against postharvest fruit pathogenic fungi. Comparison with a synthetic analog and related intermediates.

Science.gov (United States)

Pergomet, Jorgelina L; Di Liberto, Melina G; Derita, Marcos G; Bracca, Andrea B J; Kaufman, Teodoro S

2018-03-01

The antifungal activity of pterophyllin 2, pterophyllin 4, a 5-desmethyl analog of the latter and some of their synthetic intermediates, against three postharvest phytopathogenic fungi, was evaluated. The target fungi were Rhizopus stolonifer, Botrytis cinerea and Monilinia fructicola, which affect fruits worldwide, causing important economic losses. The tests were carried out with imazalil and carbendazim as positive controls. Minimum inhibitory concentrations and minimum fungicidal concentrations were determined, and the morphology of the colonies was examined microscopically. In liquid medium, it was found that pterophyllin 4 exhibited selective fungicidal activity toward M. fructicola, whereas its congener pterophyllin 2 proved to be less potent and not selective and the 5-desmethyl analog of pterophyllin 4 displayed a different activity profile. Morphological changes were observed in the colonies exposed to pterophyllin 4. The results highlighted the importance of small structural features for the antifungal behavior and also suggested that, in Nature, the pterophyllins may act as plant defenses against pathogens. Copyright © 2018 Elsevier B.V. All rights reserved.

Sequencing the Major Mycosphaerella Pathogens of Wheat and Banana

NARCIS (Netherlands)

Kema, G.H.J.

2009-01-01

Mycosphaerella is one of the largest genera of plant-pathogenic fungi with more than 1,000 named species, many of which are important pathogens causing leaf spotting diseases in a wide variety of crops including cereals, citrus, banana, eucalypts, soft fruits and horticultural crops. A few species

Sequencing the Major Mycosphaerella Pathogens of Wheat and Banana

NARCIS (Netherlands)

Kema, G.H.; Dunkle, L.D.; Churchill, A.C.; Carlier, J.; James, A.; Souza, M.T.; Crous, P.W.; Roux, N.; Lee, T.A. van der; Wiitenberg, A.; Lindquist, E.; Grigoriev, I.; Bristow, J.; Goodwin, S.B.

2007-01-01

Mycosphaerella is one of the largest genera of plant pathogenic fungi with more than 1,000 named species, many of which are important pathogens causing leaf spotting diseases in a wide variety of crops including cereals, citrus, banana, eucalypts, soft fruits, and horticultural crops. A few species

Plant-microbe interactions: Plant hormone production by phylloplane fungi. Research report

Energy Technology Data Exchange (ETDEWEB)

Tuomi, T.; Ilvesoksa, J.; Rosenqvist, H.

1993-06-23

The molds Botrytis cinerea, Cladosporium cladosporioides and the yeast Aureobasidium pullulans, isolated from the leaves of three short-rotation Salix clones, were found to produce indole-3-acetic acid (a growth promoter of plants). Abscisic acid (a growth inhibitor of plants) production was detected in B. cinerea. The contents of indole-3-acetic acid and abscisic acid in the leaves of the Salix clones and the amounts of fungal propagules in these leaves were also measured, in order to evaluate whether the amounts of plant growth regulators produced by the fungi would make a significant contribution to the hormonal quantities of the leaves. The content of abscisic acid, and to a lesser degree that of indole-3-acetic acid, showed a positive correlation with the frequency of infection by the hormone producing organisms. The amounts of hormone producing fungi on leaves that bore visible colonies were, however, not sufficiently high to support the argument that neither the fungal production of abscisic nor indole-3-acetic acid would to a significant degree contribute to the hormonal contents of the leaves of the Salix clones.

Inhibition of in vitro growth of soil-borne pathogens by compost-inhabiting indigenous bacteria and fungi

International Nuclear Information System (INIS)

Ramzan, N.; Noreen, N.; Shahzad, S.

2014-01-01

During the present studies, compost-inhabiting microorganisms including 44 fungi and 15 bacteria isolated from different compost samples were evaluated for their in vitro efficacy against soil-borne pathogens viz., Fusarium solani, Macrophomina phaseolina, Pythium aphanidermatum, Rhizoctonia solani, and Sclerotium rolfsii. Compost inhabiting microbes like Trichoderma harzianum, T. virens, Bacillus cereus, B. pumilus, B. subtilis, Micrococcus varians and Pseudomonas fluorescens were found to inhibit all the test pathogens. Acrophialophora fusispora and Penicillium citrinum reduced the mycelial growth of all the test pathogens except Sclerotium rolfsii. Bacillus licheniformis and Bacillus megaterium showed biocontrol activity against all the pathogens except Rhizoctonia solani. Trichoderma harzianum parasitized mycelia of all the tested pathogens and produced coiling around the mycelium. (author)

First survey on ecological host range of aphid pathogenic fungi (Phylum Entomophthoromycota) in Tunisia

DEFF Research Database (Denmark)

Ben Fekih, Ibtissem; Boukhris-Bouhachem, Sonia; Allagui, Mohamed Bechir

2015-01-01

Summary. The natural occurrence of fungal pathogens of aphids and their ecological host range was investigated in Tunisia from 2009 to 2012. The survey focused on aphid infesting different crops and weeds and included 10 different aphid species. Samples were collected from eight agricultural crops...... (Entomophthorales: Ancylistaceae) and Neozygites fresenii (Neozygitales: Neozygitaceae). The occurrence of entomophthoralean fungi depended on the sampling area, the bioclimatic zone, and aphid species. P. neoaphidis and E. planchoniana were the predominant pathogens infecting a wide range of aphid species whereas...... sites belonging to three different bioclimatic zones. Four pathogens from the phylum Entomophthoromycota were found to occur naturally in Tunisian ecosystems: Pandora neoaphidis (Entomophthorales: Entomophthoraceae), Entomophthora planchoniana (Entomophthorales: Entomophthoraceae), Conidiobolus obscurus...

Function and Biosynthesis of Cell Wall α-1,3-Glucan in Fungi

Directory of Open Access Journals (Sweden)

Akira Yoshimi

2017-11-01

Full Text Available Although α-1,3-glucan is a major cell wall polysaccharide in filamentous fungi, its biological functions remain unclear, except that it acts as a virulence factor in animal and plant pathogenic fungi: it conceals cell wall β-glucan on the fungal cell surface to circumvent recognition by hosts. However, cell wall α-1,3-glucan is also present in many of non-pathogenic fungi. Recently, the universal function of α-1,3-glucan as an aggregation factor has been demonstrated. Applications of fungi with modified cell wall α-1,3-glucan in the fermentation industry and of in vitro enzymatically-synthesized α-1,3-glucan in bio-plastics have been developed. This review focuses on the recent progress in our understanding of the biological functions and biosynthetic mechanism of cell wall α-1,3-glucan in fungi. We briefly consider the history of studies on α-1,3-glucan, overview its biological functions and biosynthesis, and finally consider the industrial applications of fungi deficient in α-1,3-glucan.

Mycoparasitism studies of Trichoderma species against three phytopathogenic fungi: evaluation of antagonism and hydrolytic enzyme production.

Science.gov (United States)

Qualhato, Thiago Fernandes; Lopes, Fabyano Alvares Cardoso; Steindorff, Andrei Stecca; Brandão, Renata Silva; Jesuino, Rosália Santos Amorim; Ulhoa, Cirano José

2013-09-01

Trichoderma spp. are used for biocontrol of several plant pathogens. However, their efficient interaction with the host needs to be accompanied by production of secondary metabolites and cell wall-degrading enzymes. Three parameters were evaluated after interaction between four Trichoderma species and plant-pathogenic fungi: Fusarium solani, Rhizoctonia solani and Sclerotinia sclerotiorum. Trichoderma harzianum and T. asperellum were the most effective antagonists against the pathogens. Most of the Trichoderma species produced toxic volatile metabolites, having significant effects on growth and development of the plant pathogens. When these species were grown in liquid cultures with cell walls from these plant pathogens, they produced and secreted β-1,3-glucanase, NAGAse, chitinase, acid phosphatase, acid proteases and alginate lyase.

Effector proteins of rust fungi.

Science.gov (United States)

Petre, Benjamin; Joly, David L; Duplessis, Sébastien

2014-01-01

Rust fungi include many species that are devastating crop pathogens. To develop resistant plants, a better understanding of rust virulence factors, or effector proteins, is needed. Thus far, only six rust effector proteins have been described: AvrP123, AvrP4, AvrL567, AvrM, RTP1, and PGTAUSPE-10-1. Although some are well established model proteins used to investigate mechanisms of immune receptor activation (avirulence activities) or entry into plant cells, how they work inside host tissues to promote fungal growth remains unknown. The genome sequences of four rust fungi (two Melampsoraceae and two Pucciniaceae) have been analyzed so far. Genome-wide analyses of these species, as well as transcriptomics performed on a broader range of rust fungi, revealed hundreds of small secreted proteins considered as rust candidate secreted effector proteins (CSEPs). The rust community now needs high-throughput approaches (effectoromics) to accelerate effector discovery/characterization and to better understand how they function in planta. However, this task is challenging due to the non-amenability of rust pathosystems (obligate biotrophs infecting crop plants) to traditional molecular genetic approaches mainly due to difficulties in culturing these species in vitro. The use of heterologous approaches should be promoted in the future.

Genome-Wide Annotation and Comparative Analysis of Cytochrome P450 Monooxygenases in Basidiomycete Biotrophic Plant Pathogens.

Directory of Open Access Journals (Sweden)

Lehlohonolo Benedict Qhanya

Full Text Available Fungi are an exceptional source of diverse and novel cytochrome P450 monooxygenases (P450s, heme-thiolate proteins, with catalytic versatility. Agaricomycotina saprophytes have yielded most of the available information on basidiomycete P450s. This resulted in observing similar P450 family types in basidiomycetes with few differences in P450 families among Agaricomycotina saprophytes. The present study demonstrated the presence of unique P450 family patterns in basidiomycete biotrophic plant pathogens that could possibly have originated from the adaptation of these species to different ecological niches (host influence. Systematic analysis of P450s in basidiomycete biotrophic plant pathogens belonging to three different orders, Agaricomycotina (Armillaria mellea, Pucciniomycotina (Melampsora laricis-populina, M. lini, Mixia osmundae and Puccinia graminis and Ustilaginomycotina (Ustilago maydis, Sporisorium reilianum and Tilletiaria anomala, revealed the presence of numerous putative P450s ranging from 267 (A. mellea to 14 (M. osmundae. Analysis of P450 families revealed the presence of 41 new P450 families and 27 new P450 subfamilies in these biotrophic plant pathogens. Order-level comparison of P450 families between biotrophic plant pathogens revealed the presence of unique P450 family patterns in these organisms, possibly reflecting the characteristics of their order. Further comparison of P450 families with basidiomycete non-pathogens confirmed that biotrophic plant pathogens harbour the unique P450 families in their genomes. The CYP63, CYP5037, CYP5136, CYP5137 and CYP5341 P450 families were expanded in A. mellea when compared to other Agaricomycotina saprophytes and the CYP5221 and CYP5233 P450 families in P. graminis and M. laricis-populina. The present study revealed that expansion of these P450 families is due to paralogous evolution of member P450s. The presence of unique P450 families in these organisms serves as evidence of how a host

Chemical signaling between plants and plant-pathogenic bacteria.

Science.gov (United States)

Venturi, Vittorio; Fuqua, Clay

2013-01-01

Studies of chemical signaling between plants and bacteria in the past have been largely confined to two models: the rhizobial-legume symbiotic association and pathogenesis between agrobacteria and their host plants. Recent studies are beginning to provide evidence that many plant-associated bacteria undergo chemical signaling with the plant host via low-molecular-weight compounds. Plant-produced compounds interact with bacterial regulatory proteins that then affect gene expression. Similarly, bacterial quorum-sensing signals result in a range of functional responses in plants. This review attempts to highlight current knowledge in chemical signaling that takes place between pathogenic bacteria and plants. This chemical communication between plant and bacteria, also referred to as interkingdom signaling, will likely become a major research field in the future, as it allows the design of specific strategies to create plants that are resistant to plant pathogens.

Differential responses of soil bacteria, fungi, archaea and protists to plant species richness and plant functional group identity.

Science.gov (United States)

Dassen, Sigrid; Cortois, Roeland; Martens, Henk; de Hollander, Mattias; Kowalchuk, George A; van der Putten, Wim H; De Deyn, Gerlinde B

2017-08-01

Plants are known to influence belowground microbial community structure along their roots, but the impacts of plant species richness and plant functional group (FG) identity on microbial communities in the bulk soil are still not well understood. Here, we used 454-pyrosequencing to analyse the soil microbial community composition in a long-term biodiversity experiment at Jena, Germany. We examined responses of bacteria, fungi, archaea, and protists to plant species richness (communities varying from 1 to 60 sown species) and plant FG identity (grasses, legumes, small herbs, tall herbs) in bulk soil. We hypothesized that plant species richness and FG identity would alter microbial community composition and have a positive impact on microbial species richness. Plant species richness had a marginal positive effect on the richness of fungi, but we observed no such effect on bacteria, archaea and protists. Plant species richness also did not have a large impact on microbial community composition. Rather, abiotic soil properties partially explained the community composition of bacteria, fungi, arbuscular mycorrhizal fungi (AMF), archaea and protists. Plant FG richness did not impact microbial community composition; however, plant FG identity was more effective. Bacterial richness was highest in legume plots and lowest in small herb plots, and AMF and archaeal community composition in legume plant communities was distinct from that in communities composed of other plant FGs. We conclude that soil microbial community composition in bulk soil is influenced more by changes in plant FG composition and abiotic soil properties, than by changes in plant species richness per se. © 2017 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.

Challenges and Strategies for Proteome Analysis of the Interaction of Human Pathogenic Fungi with Host Immune Cells.

Science.gov (United States)

Krüger, Thomas; Luo, Ting; Schmidt, Hella; Shopova, Iordana; Kniemeyer, Olaf

2015-12-14

Opportunistic human pathogenic fungi including the saprotrophic mold Aspergillus fumigatus and the human commensal Candida albicans can cause severe fungal infections in immunocompromised or critically ill patients. The first line of defense against opportunistic fungal pathogens is the innate immune system. Phagocytes such as macrophages, neutrophils and dendritic cells are an important pillar of the innate immune response and have evolved versatile defense strategies against microbial pathogens. On the other hand, human-pathogenic fungi have sophisticated virulence strategies to counteract the innate immune defense. In this context, proteomic approaches can provide deeper insights into the molecular mechanisms of the interaction of host immune cells with fungal pathogens. This is crucial for the identification of both diagnostic biomarkers for fungal infections and therapeutic targets. Studying host-fungal interactions at the protein level is a challenging endeavor, yet there are few studies that have been undertaken. This review draws attention to proteomic techniques and their application to fungal pathogens and to challenges, difficulties, and limitations that may arise in the course of simultaneous dual proteome analysis of host immune cells interacting with diverse morphotypes of fungal pathogens. On this basis, we discuss strategies to overcome these multifaceted experimental and analytical challenges including the viability of immune cells during co-cultivation, the increased and heterogeneous protein complexity of the host proteome dynamically interacting with the fungal proteome, and the demands on normalization strategies in terms of relative quantitative proteome analysis.

Cercosporoid fungi (Mycosphaerellaceae) 2. Species on monocots (Acoraceae to Xyridaceae, excluding Poaceae)

OpenAIRE

Braun, Uwe; Crous, Pedro W.; Nakashima, Chiharu

2014-01-01

Cercosporoid fungi (formerly Cercospora s. lat.) represent one of the largest groups of hyphomycetes belonging to the Mycosphaerellaceae (Ascomycota). They include asexual morphs, asexual holomorphs, or species with mycosphaerella-like sexual morphs. Most of them are leaf-spotting plant pathogens with special phytopathological relevance. In the first part of a new monographic work, cercosporoid hyphomycetes occurring on other fungi (fungicolous species), on ferns (pteridophytes) and gymnosper...

Direct plantlet inoculation with soil or insect-associated fungi may control cabbage root fly maggots.

Science.gov (United States)

Razinger, Jaka; Lutz, Matthias; Schroers, Hans-Josef; Palmisano, Marilena; Wohler, Christian; Urek, Gregor; Grunder, Jürg

2014-07-01

A potential Delia radicum biological control strategy involving cauliflower plantlet inoculation with various fungi was investigated in a series of laboratory and glasshouse experiments. In addition to entomopathogenic fungi, fungi with a high rhizosphere competence and fungi with the ability to survive as saprotrophs in soil were tested. The following fungal species were evaluated in the experiments: Trichoderma atroviride, T. koningiopsis, T. gamsii, Beauveria bassiana, Metharhizium anisopliae, M. brunneum and Clonostachys solani. A commercial carbosulfan-based insecticide was used as a positive control. Additionally, two commercial products, one based on B. bassiana (Naturalis) and one on Bacillus thuringiensis (Delfin) were used as reference biocontrol agents. The aims were (i) to assess the pathogenicity of the selected fungal isolates to Delia radicum, (ii) to evaluate the fungal isolates' rhizosphere competence, with the emphasis on the persistence of the original inoculum on the growing roots, (iii) to assess possible endophytic plant tissue colonization, and (iv) to evaluate potential plant growth stimulating effects of the added inoculi. Significant pathogenicity of tested fungi against Delia radicum was confirmed in in vitro and glasshouse experiments. All tested fungi persisted on cauliflower rhizoplane. More importantly, the added fungi were found on thoroughly washed roots outside the original point of inoculation. This provided us with evidence that our tested fungi could be transferred via or grow with the elongating roots. In addition to colonizing the rhizoplane, some fungi were found inside the plant root or stem tissue, thus exhibiting endophytic characteristics. The importance of fungal ecology as a criterion in appropriate biological control agent selection is discussed. Copyright © 2014 Elsevier Inc. All rights reserved.

MycoDB, a global database of plant response to mycorrhizal fungi

Science.gov (United States)

Chaudhary, V. Bala; Rúa, Megan A.; Antoninka, Anita; Bever, James D.; Cannon, Jeffery; Craig, Ashley; Duchicela, Jessica; Frame, Alicia; Gardes, Monique; Gehring, Catherine; Ha, Michelle; Hart, Miranda; Hopkins, Jacob; Ji, Baoming; Johnson, Nancy Collins; Kaonongbua, Wittaya; Karst, Justine; Koide, Roger T.; Lamit, Louis J.; Meadow, James; Milligan, Brook G.; Moore, John C.; Pendergast, Thomas H., IV; Piculell, Bridget; Ramsby, Blake; Simard, Suzanne; Shrestha, Shubha; Umbanhowar, James; Viechtbauer, Wolfgang; Walters, Lawrence; Wilson, Gail W. T.; Zee, Peter C.; Hoeksema, Jason D.

2016-05-01

Plants form belowground associations with mycorrhizal fungi in one of the most common symbioses on Earth. However, few large-scale generalizations exist for the structure and function of mycorrhizal symbioses, as the nature of this relationship varies from mutualistic to parasitic and is largely context-dependent. We announce the public release of MycoDB, a database of 4,010 studies (from 438 unique publications) to aid in multi-factor meta-analyses elucidating the ecological and evolutionary context in which mycorrhizal fungi alter plant productivity. Over 10 years with nearly 80 collaborators, we compiled data on the response of plant biomass to mycorrhizal fungal inoculation, including meta-analysis metrics and 24 additional explanatory variables that describe the biotic and abiotic context of each study. We also include phylogenetic trees for all plants and fungi in the database. To our knowledge, MycoDB is the largest ecological meta-analysis database. We aim to share these data to highlight significant gaps in mycorrhizal research and encourage synthesis to explore the ecological and evolutionary generalities that govern mycorrhizal functioning in ecosystems.

Genome analysis of the necrotrophic fungal pathogens Sclerotinia sclerotiorum and Botrytis cinerea

NARCIS (Netherlands)

Amselem, J.; Cuomo, C.A.; Kan, van J.A.L.; Viaud, M.; Benito, E.P.; Couloux, A.; Coutinho, P.M.; Vries, de R.P.; Dyer, P.S.; Fillinger, S.; Fournier, E.; Gout, L.; Hahn, M.; Kohn, L.; Lapalu, N.; Plummer, K.M.; Pradier, J.M.; Quévillon, E.; Sharon, A.; Simon, A.; Have, ten A.; Tudzynski, B.; Tudzynski, P.; Wincker, P.; Andrew, M.; Anthouard, V.; Beever, R.E.; Beffa, R.; Benoit, I.; Bouzid, O.; Brault, B.; Chen, Z.; Choquer, M.; Collemare, J.; Cotton, P.; Danchin, E.G.; Silva, Da C.; Gautier, A.; Giraud, C.; Giraud, T.; Gonzalez, C.; Grossetete, S.; Güldener, U.; Henrissat, B.; Howlett, B.J.; Kodira, C.; Kretschmer, M.; Lappartient, A.; Leroch, M.; Levis, C.; Mauceli, E.; Neuvéglise, C.; Oeser, B.; Pearson, M.; Poulain, J.; Poussereau, N.; Quesneville, H.; Rascle, C.; Schumacher, J.; Ségurens, B.; Sexton, A.; Silva, E.; Sirven, C.; Soanes, D.M.; Talbot, N.J.; Templeton, M.; Yandava, C.; Yarden, O.; Zeng, Q.; Rollins, J.A.; Lebrun, M.H.; Dickman, M.

2011-01-01

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.

Tomato Cf resistance proteins mediate recognition of cognate homologous effectors from fungi pathogenic on dicots and monocots.

Science.gov (United States)

Stergiopoulos, Ioannis; van den Burg, Harrold A; Okmen, Bilal; Beenen, Henriek G; van Liere, Sabine; Kema, Gert H J; de Wit, Pierre J G M

2010-04-20

Most fungal effectors characterized so far are species-specific and facilitate virulence on a particular host plant. During infection of its host tomato, Cladosporium fulvum secretes effectors that function as virulence factors in the absence of cognate Cf resistance proteins and induce effector-triggered immunity in their presence. Here we show that homologs of the C. fulvum Avr4 and Ecp2 effectors are present in other pathogenic fungi of the Dothideomycete class, including Mycosphaerella fijiensis, the causal agent of black Sigatoka disease of banana. We demonstrate that the Avr4 homolog of M. fijiensis is a functional ortholog of C. fulvum Avr4 that protects fungal cell walls against hydrolysis by plant chitinases through binding to chitin and, despite the low overall sequence homology, triggers a Cf-4-mediated hypersensitive response (HR) in tomato. Furthermore, three homologs of C. fulvum Ecp2 are found in M. fijiensis, one of which induces different levels of necrosis or HR in tomato lines that lack or contain a putative cognate Cf-Ecp2 protein, respectively. In contrast to Avr4, which acts as a defensive virulence factor, M. fijiensis Ecp2 likely promotes virulence by interacting with a putative host target causing host cell necrosis, whereas Cf-Ecp2 could possibly guard the virulence target of Ecp2 and trigger a Cf-Ecp2-mediated HR. Overall our data suggest that Avr4 and Ecp2 represent core effectors that are collectively recognized by single cognate Cf-proteins. Transfer of these Cf genes to plant species that are attacked by fungi containing these cognate core effectors provides unique ways for breeding disease-resistant crops.

Genome wide analysis of the transition to pathogenic lifestyles in Magnaporthales fungi

Science.gov (United States)

The rice blast fungus Pyricularia oryzae (syn. Magnaporthe oryzae, Magnaporthe grisea), a member of the order Magnaporthales in the class Sordariomycetes, is an important plant pathogen and a model species for studying pathogen infection and plant-fungal interaction. In this study, we generated geno...

Uncovering plant-pathogen crosstalk through apoplastic proteomic studies.

Science.gov (United States)

Delaunois, Bertrand; Jeandet, Philippe; Clément, Christophe; Baillieul, Fabienne; Dorey, Stéphan; Cordelier, Sylvain

2014-01-01

Plant pathogens have evolved by developing different strategies to infect their host, which in turn have elaborated immune responses to counter the pathogen invasion. The apoplast, including the cell wall and extracellular space outside the plasma membrane, is one of the first compartments where pathogen-host interaction occurs. The plant cell wall is composed of a complex network of polysaccharides polymers and glycoproteins and serves as a natural physical barrier against pathogen invasion. The apoplastic fluid, circulating through the cell wall and intercellular spaces, provides a means for delivering molecules and facilitating intercellular communications. Some plant-pathogen interactions lead to plant cell wall degradation allowing pathogens to penetrate into the cells. In turn, the plant immune system recognizes microbial- or damage-associated molecular patterns (MAMPs or DAMPs) and initiates a set of basal immune responses, including the strengthening of the plant cell wall. The establishment of defense requires the regulation of a wide variety of proteins that are involved at different levels, from receptor perception of the pathogen via signaling mechanisms to the strengthening of the cell wall or degradation of the pathogen itself. A fine regulation of apoplastic proteins is therefore essential for rapid and effective pathogen perception and for maintaining cell wall integrity. This review aims to provide insight into analyses using proteomic approaches of the apoplast to highlight the modulation of the apoplastic protein patterns during pathogen infection and to unravel the key players involved in plant-pathogen interaction.

Antifungal Activity of Decyl Gallate against Several Species of Pathogenic Fungi

Directory of Open Access Journals (Sweden)

Ana Carolina Alves de Paula e Silva

2014-01-01

Full Text Available This work aims to demonstrate that the gallic acid structure modification to the decyl gallate (G14 compound contributed to increase the antifungal activity against several species of pathogenic fungi, mainly, Candida spp., Cryptococcus spp., Paracoccidioides spp., and Histoplasma capsulatum, according to standardized microdilution method described by Clinical Laboratory Standard Institute (CLSI documents. Moreover this compound has a particularly good selectivity index value, which makes it an excellent candidate for broad-spectrum antifungal prototype and encourages the continuation of subsequent studies for the discovery of its mechanism of action.

FungiDB: An Integrated Bioinformatic Resource for Fungi and Oomycetes

Directory of Open Access Journals (Sweden)

Evelina Y. Basenko

2018-03-01

Full Text Available FungiDB (fungidb.org is a free online resource for data mining and functional genomics analysis for fungal and oomycete species. FungiDB is part of the Eukaryotic Pathogen Genomics Database Resource (EuPathDB, eupathdb.org platform that integrates genomic, transcriptomic, proteomic, and phenotypic datasets, and other types of data for pathogenic and nonpathogenic, free-living and parasitic organisms. FungiDB is one of the largest EuPathDB databases containing nearly 100 genomes obtained from GenBank, Aspergillus Genome Database (AspGD, The Broad Institute, Joint Genome Institute (JGI, Ensembl, and other sources. FungiDB offers a user-friendly web interface with embedded bioinformatics tools that support custom in silico experiments that leverage FungiDB-integrated data. In addition, a Galaxy-based workspace enables users to generate custom pipelines for large-scale data analysis (e.g., RNA-Seq, variant calling, etc.. This review provides an introduction to the FungiDB resources and focuses on available features, tools, and queries and how they can be used to mine data across a diverse range of integrated FungiDB datasets and records.

Plants, plant pathogens, and microgravity--a deadly trio

Science.gov (United States)

Leach, J. E.; Ryba-White, M.; Sun, Q.; Wu, C. J.; Hilaire, E.; Gartner, C.; Nedukha, O.; Kordyum, E.; Keck, M.; Leung, H.;

When green and red mycology meet: Impressions from an interdisciplinary forum on virulence mechanisms of phyto- and human-pathogenic fungi.

Science.gov (United States)

Yu, Yidong; Hube, Bernhard; Kämper, Jörg; Meyer, Vera; Krappmann, Sven

2017-10-03

Fungal infections pose a constant threat to plants and humans, but detailed knowledge about pathogenesis, immunity, or virulence is rather scarce. Due to the fact that a certain overlap in the armoury of infection exists between plant- and human-pathogenic fungi, an interdisciplinary forum was held in October 2016 at the Institute for Clinical Microbiology, Immunology and Hygiene in Erlangen under the organisational umbrella from two special interest groups of German microbial societies. Scientific exchange and intense discussion of this timely topic was fostered by bringing together renowned experts in their respective fields to present their thoughts and recent findings in the course of a plenary lecture and six themed sessions, accompanied by oral and poster contributions of young researchers. By targeting the topic of fungal virulence mechanisms from various angles and in the context of plant and human hosts, some common grounds and exciting perspectives could be deduced during this vibrant scientific event.

Dung-inhabiting fungi: a potential reservoir of novel secondary metabolites for the control of plant pathogens.

Science.gov (United States)

Sarrocco, Sabrina

2016-04-01

Coprophilous fungi are a large group of saprotrophic fungi mostly found in herbivore dung. The number of these fungi undergoing investigation is continually increasing, and new species and genera continue to be described. Dung-inhabiting fungi play an important ecological role in decomposing and recycling nutrients from animal dung. They produce a large array of bioactive secondary metabolites and have a potent enzymatic arsenal able to utilise even complex molecules. Bioactive secondary metabolites are actively involved in interaction with and defence against other organisms whose growth can be inhibited, resulting in an enhanced ecological fitness of producer strains. Currently, these antibiotics and bioactive secondary metabolites are of interest in medicine in particular, while very little information is available concerning their potential use in agriculture. This review introduces the ecology of dung-inhabiting fungi, with particular emphasis on the production of antibiotic compounds as a means to compete with other microorganisms. Owing to the fast pace of technological progress, new approaches to predicting the biosynthesis of bioactive metabolites are proposed. Coprophilous fungi should be considered as elite candidate organisms for the discovery of novel antifungal compounds, above all in view of their exploitation for crop protection. © 2015 Society of Chemical Industry.

Complete genome sequence of Serratia sp. YD25 (KCTC 42987) presenting strong antagonistic activities to various pathogenic fungi and bacteria.

Science.gov (United States)

Su, Chun; Liu, Yibo; Sun, Yan; Li, Zhi

2017-03-10

Serratia sp. YD25 (KCTC 42987) was originally isolated from rhizosphere soil in a continuous cropping tobacco-planting farm. Here, we show that its metabolites efficiently suppress the growth of various important pathogenic fungi and bacteria, causing infection in both plants and humans. In addition, Serratia sp. YD25 has a special trait of simultaneous production of both serrawettin W2 and prodigiosin, two important bioactive secondary metabolites produced by Serratia strains. Such co-production has not been reported in other Serratia strains. The complete genome sequence of Serratia sp. YD25 is presented, which is valuable for further exploration of its biotechnological applications in agriculture and medicine. The genome sequence reported here is also useful for understanding the unique regulatory mechanisms underlying biosynthesis of active compounds. Copyright © 2017 Elsevier B.V. All rights reserved.

Flexible gateway constructs for functional analyses of genes in plant pathogenic fungi

NARCIS (Netherlands)

Mehrabi, Rahim; Mirzadi Gohari, Amir; Silva, da Gilvan Ferreira; Steinberg, Gero; Kema, Gert H.J.; Wit, de Pierre J.G.M.

2015-01-01

Genetic manipulation of fungi requires quick, low-cost, efficient, high-throughput and molecular tools. In this paper, we report 22 entry constructs as new molecular tools based on the Gateway technology facilitating rapid construction of binary vectors that can be used for functional analysis of

Plant Extract Control of the Fungi Associated with Different Egyptian Wheat Cultivars Grains

Directory of Open Access Journals (Sweden)

Mohamed Baka Zakaria Awad

2014-07-01

Full Text Available Grain samples of 14 Egyptian wheat cultivars were tested for seed-borne fungi. The deep freezing method was used. Five seed-borne fungi viz., Aspergillus flavus, A. niger, Curvularia lunata, Fusarium moniliforme and Penicillium chrysogenum were isolated from the wheat cultivars viz., Bani Suef 4, Bani Suef 5, Gemmiza 7, Gemmiza 9, Gemmiza 10, Giza 168, Misr 1, Misr 2, Sakha 93, Sakha 94, Shandaweel 1, Sids 1, Sids 2 and Sids 3. A. flavus, A. niger and F. moniliforme were the most prevalent fungal species. Their incidence ranged from 21.0-53.5%, 16.0-37.5%, and 12.0-31.0%, respectively. The antifungal potential of water extracts from aerial parts of five wild medicinal plants (Asclepias sinaica, Farsetia aegyptia, Hypericum sinaicum, Phagnalon sinaicum, and Salvia aegyptiaca were collected from the Sinai Peninsula, Egypt. The antifungal potential of water extracts from the aerial parts of these five plants were tested in the laboratory against the dominant fungi isolated from the wheat cultivars. All the aqueous plant extracts significantly (p ≤ 0.05 reduced the incidence of the tested seed-borne fungi. But the extract of Asclepias sinaica exhibited the most antifungal activity on tested fungi at all concentrations used when compared with other plant extracts. Maximum infested grain germination was observed in Giza 168 and minimum in Bani Suef 5. Treating grains with plant extract of A. sinaica (10% enhanced the percentage of grain germination of all cultivars in both laboratory and pot experiments. Maximum root and shoot length of seedlings was recorded in Bani Suef 4 during fungal infestation or treatment by plant extract. For one hour before sowing or storage, the aqueous extract of A. sinaica can be used to treat wheat grains, to reduce the fungal incidence. Aqueous extracts of the aerial parts of selected medicinal plants, particularly A. sinaica, are promising for protecting Egyptian wheat grain cultivars against major seed-borne fungi

The diversity of fungi colonizing necrotic inflorescence buds of rhododendron (Rhododendron L.

Directory of Open Access Journals (Sweden)

Małgorzata Żołna

2013-07-01

Full Text Available The infection of rhododendron (Rhododendron L. inflorescence buds caused by pathogenic fungi induces its browning, withering, and dieback. The identification of fungi causing the infection of rhododendron inflorescence buds can be a reason for creating new improved cultivars with genetically determined resistance to pathogens. The investigations were carried out in 2010–2011 on the collection of ornamental plants of the Faculty of Horticulture, University of Agriculture in Kraków. The material comprised infected inflorescence buds collected from nine newly bred taxa and one botanical species of rhododendron. 596 colonies of fungi belonging to 31 species were isolated from infected rhododendron inflorescence buds. The dominant species were: Pestalotiopsis sydowiana, Truncatella truncata, Alternaria alternata, Phialophora asteris, and Trichoderma viride, which constituted almost 74% of the isolated fungi population. Boeremia exigua var. exigua, Epicoccum nigrum, Fusarium poae, Mammaria echinobotryoides, Paraphoma chrysanthemicola, Phialophora cyclaminis, Phoma eupyrena, Talaromyces wortmannii, Umbelopsis isabellina, and other fungi were isolated in a lower number. The results of mycological analysis confirm the diversity of species colonizing necrotic inflorescence buds of rhododendron. .

Nutrition acquisition strategies during fungal infection of plants.

Science.gov (United States)

Divon, Hege H; Fluhr, Robert

2007-01-01

In host-pathogen interactions, efficient pathogen nutrition is a prerequisite for successful colonization and fungal fitness. Filamentous fungi have a remarkable capability to adapt and exploit the external nutrient environment. For phytopathogenic fungi, this asset has developed within the context of host physiology and metabolism. The understanding of nutrient acquisition and pathogen primary metabolism is of great importance in the development of novel disease control strategies. In this review, we discuss the current knowledge on how plant nutrient supplies are utilized by phytopathogenic fungi, and how these activities are controlled. The generation and use of auxotrophic mutants have been elemental to the determination of essential and nonessential nutrient compounds from the plant. Considerable evidence indicates that pathogen entrainment of host metabolism is a widespread phenomenon and can be accomplished by rerouting of the plant's responses. Crucial fungal signalling components for nutrient-sensing pathways as well as their developmental dependency have now been identified, and were shown to operate in a coordinate cross-talk fashion that ensures proper nutrition-related behaviour during the infection process.

Influence of mycorrhizal fungi (glomus intraradices) on survival of Salmonella and E.coli 0157:H7 in soil and translocation into romaine lettuce roots and shoot

Science.gov (United States)

Modern agriculture practices disrupt the natural symbiotic relationship that arbuscular mycorrhizal (AM) fungi have with most vegetable plants, which may affect translocation of human pathogens into the plant and/or survival in the soil. AM-fungi are frequently utilized in organic farming to improv...

In Vitro Morphogenesis of Arabidopsis to Search for Novel Endophytic Fungi Modulating Plant Growth.

Directory of Open Access Journals (Sweden)

Francesco Dovana

Full Text Available Fungal endophytes have shown to affect plant growth and to confer stress tolerance to the host; however, effects of endophytes isolated from water plants have been poorly investigated. In this study, fungi isolated from stems (stem-E and roots (root-E of Mentha aquatica L. (water mint were identified, and their morphogenetic properties analysed on in vitro cultured Arabidopsis (L. Heynh., 14 and 21 days after inoculation (DAI. Nineteen fungi were analysed and, based on ITS analysis, 17 isolates showed to be genetically distinct. The overall effect of water mint endophytes on Arabidopsis fresh (FW and dry weight (DW was neutral and positive, respectively, and the increased DW, mainly occurring 14 DAI, was possibly related to plant defence mechanism. Only three fungi increased both FW and DW of Arabidopsis at 14 and 21 DAI, thus behaving as plant growth promoting (PGP fungi. E-treatment caused a reduction of root depth and primary root length in most cases and inhibition-to-promotion of root area and lateral root length, from 14 DAI. Only Phoma macrostoma, among the water mint PGP fungi, increased both root area and depth, 21 DAI. Root depth and area 14 DAI were shown to influence DWs, indicating that the extension of the root system, and thus nutrient uptake, was an important determinant of plant dry biomass. Reduction of Arabidopsis root depth occurred to a great extent when plants where treated with stem-E while root area decreased or increased under the effects of stem-E and root-E, respectively, pointing to an influence of the endophyte origin on root extension. M. aquatica and many other perennial hydrophytes have growing worldwide application in water pollution remediation. The present study provided a model for directed screening of endophytes able to modulate plant growth in the perspective of future field applications of these fungi.

In Vitro Morphogenesis of Arabidopsis to Search for Novel Endophytic Fungi Modulating Plant Growth.

Science.gov (United States)

Dovana, Francesco; Mucciarelli, Marco; Mascarello, Maurizio; Fusconi, Anna

2015-01-01

Fungal endophytes have shown to affect plant growth and to confer stress tolerance to the host; however, effects of endophytes isolated from water plants have been poorly investigated. In this study, fungi isolated from stems (stem-E) and roots (root-E) of Mentha aquatica L. (water mint) were identified, and their morphogenetic properties analysed on in vitro cultured Arabidopsis (L.) Heynh., 14 and 21 days after inoculation (DAI). Nineteen fungi were analysed and, based on ITS analysis, 17 isolates showed to be genetically distinct. The overall effect of water mint endophytes on Arabidopsis fresh (FW) and dry weight (DW) was neutral and positive, respectively, and the increased DW, mainly occurring 14 DAI, was possibly related to plant defence mechanism. Only three fungi increased both FW and DW of Arabidopsis at 14 and 21 DAI, thus behaving as plant growth promoting (PGP) fungi. E-treatment caused a reduction of root depth and primary root length in most cases and inhibition-to-promotion of root area and lateral root length, from 14 DAI. Only Phoma macrostoma, among the water mint PGP fungi, increased both root area and depth, 21 DAI. Root depth and area 14 DAI were shown to influence DWs, indicating that the extension of the root system, and thus nutrient uptake, was an important determinant of plant dry biomass. Reduction of Arabidopsis root depth occurred to a great extent when plants where treated with stem-E while root area decreased or increased under the effects of stem-E and root-E, respectively, pointing to an influence of the endophyte origin on root extension. M. aquatica and many other perennial hydrophytes have growing worldwide application in water pollution remediation. The present study provided a model for directed screening of endophytes able to modulate plant growth in the perspective of future field applications of these fungi.

Sugar catabolism in Aspergillus and other fungi related to the utilization of plant biomass

NARCIS (Netherlands)

Khosravi, Claire; Benocci, Tiziano; Battaglia, Evy; Benoit, Isabelle; de Vries, Ronald P

2015-01-01

Fungi are found in all natural and artificial biotopes and can use highly diverse carbon sources. They play a major role in the global carbon cycle by decomposing plant biomass and this biomass is the main carbon source for many fungi. Plant biomass is composed of cell wall polysaccharides

Using hierarchical clustering of secreted protein families to classify and rank candidate effectors of rust fungi

Science.gov (United States)

Rust fungi are obligate biotrophic pathogens causing considerable damage on crop plants. P. graminis f. sp. tritici, the causal agent of wheat stem rust, and M. larici-populina, the poplar rust pathogen, have strong deleterious impact on wheat and poplar wood production, respectively. The recently r...

Comparative Genome Analysis of Basidiomycete Fungi

Energy Technology Data Exchange (ETDEWEB)

Riley, Robert; Salamov, Asaf; Morin, Emmanuelle; Nagy, Laszlo; Manning, Gerard; Baker, Scott; Brown, Daren; Henrissat, Bernard; Levasseur, Anthony; Hibbett, David; Martin, Francis; Grigoriev, Igor

2012-03-19

Fungi of the phylum Basidiomycota (basidiomycetes), make up some 37percent of the described fungi, and are important in forestry, agriculture, medicine, and bioenergy. This diverse phylum includes the mushrooms, wood rots, symbionts, and plant and animal pathogens. To better understand the diversity of phenotypes in basidiomycetes, we performed a comparative analysis of 35 basidiomycete fungi spanning the diversity of the phylum. Phylogenetic patterns of lignocellulose degrading genes suggest a continuum rather than a sharp dichotomy between the white rot and brown rot modes of wood decay. Patterns of secondary metabolic enzymes give additional insight into the broad array of phenotypes found in the basidiomycetes. We suggest that the profile of an organism in lignocellulose-targeting genes can be used to predict its nutritional mode, and predict Dacryopinax sp. as a brown rot; Botryobasidium botryosum and Jaapia argillacea as white rots.

Distribution of dominant arbuscular mycorrhizal fungi among five plant species in undisturbed vegetation of a coastal grassland

DEFF Research Database (Denmark)

Holtgrewe-Stukenbrock, Eva; Rosendahl, Søren

2005-01-01

Most plant species in mixed grassland vegetation are colonized by arbuscular mycorrhizal (AM) fungi. Previous studies have reported differences in host preferences among AM fungi, although the fungi are known to lack host specificity. In the present study, the distribution of phylogenetic groups...... of AM fungi belonging to a clade of Glomus species was studied in five plant species from a coastal grassland in Denmark. The occurrence of the fungi was determined by PCR analyses of fungal large subunit ribosomal DNA sequences amplified from root fragments using a specific primer set. The results...... showed that the dominant Glomus species were able to colonize all the studied plant species, supporting the view that the AM fungi represent a large underground interconnecting mycelial network....

Take advantage of mycorrhizal fungi for improved soil fertility and plant health

Science.gov (United States)

Arbuscular mycorrhizal [AM] fungi are naturally-occurring soil fungi that form a beneficial symbiosis with the roots of most crops. The plants benefit because the symbiosis increases mineral nutrient uptake, drought resistance, and disease resistance. These characteristics make utilization of AM f...

Antimicrobial activity of broccoli (Brassica oleracea var. italica) cultivar Avenger against pathogenic bacteria, phytopathogenic filamentous fungi and yeast.

Science.gov (United States)

Pacheco-Cano, R D; Salcedo-Hernández, R; López-Meza, J E; Bideshi, D K; Barboza-Corona, J E

2018-01-01

The objective of this study was to show whether the edible part of broccoli has antibacterial and antifungal activity against micro-organism of importance in human health and vegetable spoilage, and to test if this effect was partially due to antimicrobial peptides (AMPs). Crude extracts were obtained from florets and stems of broccoli cultivar Avenger and the inhibitory effect was demonstrated against pathogenic bacteria (Bacillus cereus, Staphylococcus xylosus, Staphylococcus aureus, Shigella flexneri, Shigella sonnei, Proteus vulgaris), phytopathogenic fungi (Colletotrichum gloeosporioides, Asperigillus niger) and yeasts (Candida albicans and Rhodotorula sp.). It was shown that samples treated with proteolytic enzymes had a reduction of approximately 60% in antibacterial activity against Staph. xylosus, suggesting that proteinaceous compounds might play a role in the inhibitory effect. Antimicrobial components in crude extracts were thermoresistant and the highest activity was observed under acidic conditions. It was shown that antifungal activity of broccoli's crude extracts might not be attributed to chitinases. Organic broccoli cultivar Avenger has antimicrobial activity against pathogenic bacteria, yeast and phytophatogenic fungi. Data suggest that this effect is partially due to AMPs. Broccoli's crude extracts have activity not only against pathogenic bacteria but also against phytophatogenic fungi of importance in agriculture. We suggest for first time that the inhibitory effect is probably due to AMPs. © 2017 The Society for Applied Microbiology.

Diversity and Biological Activities of Endophytic Fungi Associated with Micropropagated Medicinal Plant Echinacea purpurea (L.) Moench

Science.gov (United States)

2012-08-01

1105 Diversity and Biological Activities of Endophytic Fungi Associated with Micropropagated Medicinal Plant Echinacea purpurea (L.) Moench Luiz H...fungal community and micropropagated clones of E. purpurea was re-established after acclimatization to soil and the endophytic fungi produced compounds...Diversity and Biological Activities of Endophytic Fungi Associated with Micropropagated Medicinal Plant Echinacea purpurea (L.) Moench 5a. CONTRACT

Wild Honey Inhibits Growth od Some Phytopathogenic Fungi in vitro

OpenAIRE

K.I. Al-Mughrabi

2003-01-01

Wild honey was diluted to 1000 ppm with sterile distilled water and tested in vitro for inhibition of the plant pathogenic fungi Fusarium oxysporum, Rhizoctonia solani, Alternaria solani, Stemphylium solani, Colletotrichum sp., and Phytophthora infestans. Wild honey was effective against all these fungi, particularly A. solani and P. infestans, the causal agents of early and late blight diseases respectively; also against R. solani and F. oxysporum, and to a less extent against S....

Filamentous Fungi.

Science.gov (United States)

Powers-Fletcher, Margaret V; Kendall, Brian A; Griffin, Allen T; Hanson, Kimberly E

2016-06-01

Filamentous mycoses are often associated with significant morbidity and mortality. Prompt diagnosis and aggressive treatment are essential for good clinical outcomes in immunocompromised patients. The host immune response plays an essential role in determining the course of exposure to potential fungal pathogens. Depending on the effectiveness of immune response and the burden of organism exposure, fungi can either be cleared or infection can occur and progress to a potentially fatal invasive disease. Nonspecific cellular immunity (i.e., neutrophils, natural killer [NK] cells, and macrophages) combined with T-cell responses are the main immunologic mechanisms of protection. The most common potential mold pathogens include certain hyaline hyphomycetes, endemic fungi, the Mucorales, and some dematiaceous fungi. Laboratory diagnostics aimed at detecting and differentiating these organisms are crucial to helping clinicians make informed decisions about treatment. The purpose of this chapter is to provide an overview of the medically important fungal pathogens, as well as to discuss the patient characteristics, antifungal-therapy considerations, and laboratory tests used in current clinical practice for the immunocompromised host.

Comparative efficacy and pathogenicity of keratinophilic soil fungi against Culex quinquefasciatus larvae.

Science.gov (United States)

Mohanty, Suman Sundar; Prakash, Soam

2010-09-01

Out of seven fungal species belonging to four genera isolated from pond and wallow soils using feathers of Pavo cristatus as bait, four species viz., Aspergillus flavus, Aspergillus niger, Chrysosporium pseudomerdarium and Trichophyton ajelloi were most frequent. Chrysosporium and Trichophyton spp. were more pathogenic on Culex quinquefasciatus larvae than Aspergillus and Penicillium. The bioefficacy tests conducted as per the protocol of World Health Organization and the LC(50) values calculated by the Probit analysis showed that 3(rd)-instar C. quinquefasciatus were more susceptible to the conidia of above fungi. Highest mortality was observed in the larvae of C. quinquefasciatus when exposed to T. ajelloi. The density of fungal conidia was greatest on the ventral brush, palmate hair and anal region of the mosquito larvae after exposing for 72 hours. The potentiality of these fungi for use in the control of C. quinquefasciatus is discussed which can be exploited as a suitable biocontrol agent in the tropics.

Chromatography in characterization of polysaccharides from medicinal plants and fungi.

Science.gov (United States)

Hu, De-jun; Cheong, Kit-leong; Zhao, Jing; Li, Shao-ping

2013-01-01

Polysaccharides isolated from medicinal plants and fungi exhibit multiple pharmacological activities. The biological activities of polysaccharides depend on their chemical characteristics. However, characterization of polysaccahrides is a challenge because of their complicated structure and macromolecular mass. In this review, chromatography in characterization of polysaccharides, including physicochemical characterization (purity, molecular mass, and distribution), structural characterization (constituent monosaccharide composition and the ratio, the features of glycosidic linkages), and fingerprint of polysaccharides (acidic and enzymatic hydrolysates), from medicinal plants and fungi were reviewed and discussed according to the publications collected in Web of Science since 2007. The perspective for characterization of polysaccharides has also been described. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Host-induced aneuploidy and phenotypic diversification in the Sudden Oak Death pathogen Phytophthora ramorum

Science.gov (United States)

Aneuploidy can result in significant phenotypic changes, which can sometimes be selectively advantageous. For example, aneuploidy confers resistance to antifungal drugs in human pathogenic fungi. Aneuploidy has also been observed in invasive fungal and oomycete plant pathogens in the field. Environm...

Mycorrhizal fungi enhance plant nutrient acquisition and modulate nitrogen loss with variable water regimes.

Science.gov (United States)

Bowles, Timothy M; Jackson, Louise E; Cavagnaro, Timothy R

2018-01-01

Climate change will alter both the amount and pattern of precipitation and soil water availability, which will directly affect plant growth and nutrient acquisition, and potentially, ecosystem functions like nutrient cycling and losses as well. Given their role in facilitating plant nutrient acquisition and water stress resistance, arbuscular mycorrhizal (AM) fungi may modulate the effects of changing water availability on plants and ecosystem functions. The well-characterized mycorrhizal tomato (Solanum lycopersicum L.) genotype 76R (referred to as MYC+) and the mutant mycorrhiza-defective tomato genotype rmc were grown in microcosms in a glasshouse experiment manipulating both the pattern and amount of water supply in unsterilized field soil. Following 4 weeks of differing water regimes, we tested how AM fungi affected plant productivity and nutrient acquisition, short-term interception of a 15NH4+ pulse, and inorganic nitrogen (N) leaching from microcosms. AM fungi enhanced plant nutrient acquisition with both lower and more variable water availability, for instance increasing plant P uptake more with a pulsed water supply compared to a regular supply and increasing shoot N concentration more when lower water amounts were applied. Although uptake of the short-term 15NH4+ pulse was higher in rmc plants, possibly due to higher N demand, AM fungi subtly modulated NO3- leaching, decreasing losses by 54% at low and high water levels in the regular water regime, with small absolute amounts of NO3- leached (<1 kg N/ha). Since this study shows that AM fungi will likely be an important moderator of plant and ecosystem responses to adverse effects of more variable precipitation, management strategies that bolster AM fungal communities may in turn create systems that are more resilient to these changes. © 2017 John Wiley & Sons Ltd.

Top 10 plant pathogenic bacteria in molecular plant pathology.

Science.gov (United States)

Mansfield, John; Genin, Stephane; Magori, Shimpei; Citovsky, Vitaly; Sriariyanum, Malinee; Ronald, Pamela; Dow, Max; Verdier, Valérie; Beer, Steven V; Machado, Marcos A; Toth, Ian; Salmond, George; Foster, Gary D

2012-08-01

Many plant bacteriologists, if not all, feel that their particular microbe should appear in any list of the most important bacterial plant pathogens. However, to our knowledge, no such list exists. The aim of this review was to survey all bacterial pathologists with an association with the journal Molecular Plant Pathology and ask them to nominate the bacterial pathogens they would place in a 'Top 10' based on scientific/economic importance. The survey generated 458 votes from the international community, and allowed the construction of a Top 10 bacterial plant pathogen list. The list includes, in rank order: (1) Pseudomonas syringae pathovars; (2) Ralstonia solanacearum; (3) Agrobacterium tumefaciens; (4) Xanthomonas oryzae pv. oryzae; (5) Xanthomonas campestris pathovars; (6) Xanthomonas axonopodis pathovars; (7) Erwinia amylovora; (8) Xylella fastidiosa; (9) Dickeya (dadantii and solani); (10) Pectobacterium carotovorum (and Pectobacterium atrosepticum). Bacteria garnering honourable mentions for just missing out on the Top 10 include Clavibacter michiganensis (michiganensis and sepedonicus), Pseudomonas savastanoi and Candidatus Liberibacter asiaticus. This review article presents a short section on each bacterium in the Top 10 list and its importance, with the intention of initiating discussion and debate amongst the plant bacteriology community, as well as laying down a benchmark. It will be interesting to see, in future years, how perceptions change and which bacterial pathogens enter and leave the Top 10. © 2012 The Authors. Molecular Plant Pathology © 2012 BSPP and Blackwell Publishing Ltd.

Phosphorylation and proteome dynamics in pathogen-resistant tomato plants

OpenAIRE

Stulemeijer, I.J.E.

2008-01-01

Microbial plant pathogens impose a continuous threat on global food production. Similar to disease resistance in mammals, an innate immune system allows plants to recognise pathogens and swiftly activate defence. For the work described in this thesis, the interaction between tomato and the extracellular fungal pathogen Cladosporium fulvum serves as a model system to study host resistance and susceptibility in plant-pathogen interactions. Resistance to C. fulvum in tomato plants follows the ge...

[Diversity and community structure of endophytic fungi from Taxus chinensis var. mairei].

Science.gov (United States)

2014-07-01

A total of 628 endophytic fungi were isolated from 480 tissue segments of needles and branches of Taxus chinensis var. mairei. According to morphological characteristics and ITS sequences, they represented 43 taxa in 28 genera, of which 10 Hyphomycetes, 20 Coelomycetes, 12 Ascomycetes and 1 unknown fungus. Phomopsis mali was confirmed as the dominant species. In accordance with relative frequency, Alternaria alternata, Aureobasidium pullulans, Colletotrichum boninense, C. gloeosporioides, Epicoccum nigrum , Fungal sp., Fusarium lateritium, Glomerella cingulata, Magnaporthales sp. , Nigrospora oryzae, Pestalotiopsis maculiformans, P. microspora, Peyronellaea glomerata and Xylaria sp. 1 were more common in T. chinensis var. mairei. T. chinensis var. mairei were severely infected by endophytic fungi. Endophytic fungi were found in 81 percent of plant tissues with a high diversity. Distribution ranges of endophytic fungi were influenced by tissue properties. The colonization rate, richness, diversity of endophytic fungi in needles were obviously lower than in branches, and kinds of endophytic fungi between branches were more similar than those in needles, thus endophytic fungi had tissue preference. In addition, tissue age influenced the community structure of endophytic fungi. The elder branch tissues were, the higher colonization rate, richness, diversity of endophytic fungi were. Systematic studying the diversity and community structure of endophytic fungi in T. chinensis var. mairei and clarifying their distribution regularity in plant tissues would offer basic data and scientific basis for their development and utilization. Discussing the presence of fungal pathogens in healthy plant tissues would be of positive significance for source protection of T. chinensis var. mairei.

Epigenetic control of effectors in plant pathogens

Directory of Open Access Journals (Sweden)

Mark eGijzen

2014-11-01

Full Text Available Plant pathogens display impressive versatility in adapting to host immune systems. Pathogen effector proteins facilitate disease but can become avirulence (Avr factors when the host acquires discrete recognition capabilities that trigger immunity. The mechanisms that lead to changes to pathogen Avr factors that enable escape from host immunity are diverse, and include epigenetic switches that allow for reuse or recycling of effectors. This perspective outlines possibilities of how epigenetic control of Avr effector gene expression may have arisen and persisted in plant pathogens, and how it presents special problems for diagnosis and detection of specific pathogen strains or pathotypes.

Plant physiology meets phytopathology: plant primary metabolism and plant-pathogen interactions.

Science.gov (United States)

Berger, Susanne; Sinha, Alok K; Roitsch, Thomas

2007-01-01

Phytopathogen infection leads to changes in secondary metabolism based on the induction of defence programmes as well as to changes in primary metabolism which affect growth and development of the plant. Therefore, pathogen attack causes crop yield losses even in interactions which do not end up with disease or death of the plant. While the regulation of defence responses has been intensively studied for decades, less is known about the effects of pathogen infection on primary metabolism. Recently, interest in this research area has been growing, and aspects of photosynthesis, assimilate partitioning, and source-sink regulation in different types of plant-pathogen interactions have been investigated. Similarly, phytopathological studies take into consideration the physiological status of the infected tissues to elucidate the fine-tuned infection mechanisms. The aim of this review is to give a summary of recent advances in the mutual interrelation between primary metabolism and pathogen infection, as well as to indicate current developments in non-invasive techniques and important strategies of combining modern molecular and physiological techniques with phytopathology for future investigations.

Host plant quality mediates competition between arbuscular mycorrhizal fungi

NARCIS (Netherlands)

Knegt, B.; Jansa, J.; Franken, O.; Engelmoer, D.J.P.; Werner, G.D.A.; Bücking, H.; Kiers, E.T.

2016-01-01

Arbuscular mycorrhizal fungi exchange soil nutrients for carbon from plant hosts. Empirical works suggests that hosts may selectively provide resources to different fungal species, ultimately affecting fungal competition. However, fungal competition may also be mediated by colonization strategies of

Phylogenetic congruence between subtropical trees and their associated fungi

NARCIS (Netherlands)

Liu, Xubing; Liang, Minxia; Etienne, Rampal S.; Gilbert, Gregory S; Yu, Shixiao

2016-01-01

Recent studies have detected phylogenetic signals in pathogen-host networks for both soil-borne and leaf-infecting fungi, suggesting that pathogenic fungi may track or coevolve with their preferred hosts. However, a phylogenetically concordant relationship between multiple hosts and multiple fungi

[Effect of flooding time length on mycorrhizal colonization of three AM fungi in two wetland plants].

Science.gov (United States)

Ma, Lei-Meng; Wang, Peng-Teng; Wang, Shu-Guang

2014-01-01

In order to provide information for elucidating effect of flooding on the formation and function of AM in wetland plants, three AM fungi (Glomus intraradices, Glomus versiforme, Glomus etunicatum) were used to investigate the effects of flooding time length on their colonization in cattail (Typha orientalis) and rice (Oryza sativa L. ). The results showed that the mycorrhizal colonization rate (MCR) presented downtrend with increasing flooding time length. In cattail, MCR of the fungus F3 was higher than those of fungi F1 and F2, but no significant difference in MCR was found between fungi F1 and F2. In rice, the MCRs of fungi F2 and F3 were higher than that of E1. In both plants, the proportional frequency of hyphae was the highest while the proportional frequency of arbuscules and vesicles was very low in all treatments, indicating that hyphal colonization was the main route for AM formation. The proportional frequency of hyphae in cattail increased with the flooding time length, but no significant trend was observed in rice plant. The proportional frequency of arhuscules decreased with the increase of flooding time, and was the highest in the treatment without flooding (treatment IV). The number of spores produced by AM fungi increased with increasing flooding time, and reached the highest in the treatment of long time flooding (treatment I). In the same treatment, the fungus F3 produced more spores than fungi F1 and F2. Changes in wet weight of the two plants showed that AM could increase cattail growth under flooding, hut little effect on rice growth was found. It is concluded that flooding time length significantly affected the mycorrhizal colonization rate and the proportional frequency of colonization. AM could enhance the growth of wetland plant, but this depends on the mycorrhizal dependence of host plant on AM fungi. Therefore, flooding time length should be considered in the inoculation of wetland plants with AM fungi.

Effect of arbuscular mycorrhizal (AM) fungi on 137Cs uptake by plants grown on different soils.

Science.gov (United States)

Vinichuk, M; Mårtensson, A; Ericsson, T; Rosén, K

2013-01-01

The potential use of mycorrhiza as a bioremediation agent for soils contaminated by radiocesium was evaluated in a greenhouse experiment. The uptake of (137)Cs by cucumber, perennial ryegrass, and sunflower after inoculation with a commercial arbuscular mycorrhizal (AM) product in soils contaminated with (137)Cs was investigated, with non-mycorrhizal quinoa included as a "reference" plant. The effect of cucumber and ryegrass inoculation with AM fungi on (137)Cs uptake was inconsistent. The effect of AM fungi was most pronounced in sunflower: both plant biomass and (137)Cs uptake increased on loamy sand and loamy soils. The total (137)Cs activity accumulated within AM host sunflower on loamy sand and loamy soils was 2.4 and 3.2-fold higher than in non-inoculated plants. Although the enhanced uptake of (137)Cs by quinoa plants on loamy soil inoculated by the AM fungi was observed, the infection of the fungi to the plants was not confirmed. Copyright © 2012 Elsevier Ltd. All rights reserved.

Interrelationships of food safety and plant pathology: the life cycle of human pathogens on plants.

Science.gov (United States)

Barak, Jeri D; Schroeder, Brenda K

2012-01-01

Bacterial food-borne pathogens use plants as vectors between animal hosts, all the while following the life cycle script of plant-associated bacteria. Similar to phytobacteria, Salmonella, pathogenic Escherichia coli, and cross-domain pathogens have a foothold in agricultural production areas. The commonality of environmental contamination translates to contact with plants. Because of the chronic absence of kill steps against human pathogens for fresh produce, arrival on plants leads to persistence and the risk of human illness. Significant research progress is revealing mechanisms used by human pathogens to colonize plants and important biological interactions between and among bacteria in planta. These findings articulate the difficulty of eliminating or reducing the pathogen from plants. The plant itself may be an untapped key to clean produce. This review highlights the life of human pathogens outside an animal host, focusing on the role of plants, and illustrates areas that are ripe for future investigation.

Effects of arbuscular mycorrhizal fungi and maternal plant sex on seed germination and early plant establishment.

Science.gov (United States)

Varga, Sandra

2015-03-01

• Arbuscular mycorrhizal fungi usually enhance overall plant performance, yet their effects on seed germination and early plant establishment, crucial steps in plant cycles, are generally overlooked. In gynodioecious species, sexual dimorphism in these traits has been reported, with females producing seeds that germinate at a faster rate than seeds from hermaphrodites.• Using the gynodioecious plant Geranium sylvaticum, I investigated in a greenhouse experiment whether the presence of arbuscular mycorrhizal spores affects seed germination and early plant establishment, examining at the same time whether the sex of the mother producing the seeds also influences these parameters and whether sex-specific interactions between these two factors exist.• The presence of arbuscular mycorrhizal spores in the soil decreased seed germination, did not affect plant survival, but did increase plant growth. Moreover, no significant differences in seed traits were detected between the sexes of the plants producing the seeds.• This study demonstrates that arbuscular mycorrhizal fungi may have contrasting effects for plants during early life stages and that mycorrhizal effects can take place even at the precolonization stage. © 2015 Botanical Society of America, Inc.

Plant Identity Exerts Stronger Effect than Fertilization on Soil Arbuscular Mycorrhizal Fungi in a Sown Pasture.

Science.gov (United States)

Zheng, Yong; Chen, Liang; Luo, Cai-Yun; Zhang, Zhen-Hua; Wang, Shi-Ping; Guo, Liang-Dong

2016-10-01

Arbuscular mycorrhizal (AM) fungi play key roles in plant nutrition and plant productivity. AM fungal responses to either plant identity or fertilization have been investigated. However, the interactive effects of different plant species and fertilizer types on these symbiotic fungi remain poorly understood. We evaluated the effects of the factorial combinations of plant identity (grasses Avena sativa and Elymus nutans and legume Vicia sativa) and fertilization (urea and sheep manure) on AM fungi following 2-year monocultures in a sown pasture field study. AM fungal extraradical hyphal density was significantly higher in E. nutans than that in A. sativa and V. sativa in the unfertilized control and was significantly increased by urea and manure in A. sativa and by manure only in E. nutans, but not by either fertilizers in V. sativa. AM fungal spore density was not significantly affected by plant identity or fertilization. Forty-eight operational taxonomic units (OTUs) of AM fungi were obtained through 454 pyrosequencing of 18S rDNA. The OTU richness and Shannon diversity index of AM fungi were significantly higher in E. nutans than those in V. sativa and/or A. sativa, but not significantly affected by any fertilizer in all of the three plant species. AM fungal community composition was significantly structured directly by plant identity only and indirectly by both urea addition and plant identity through soil total nitrogen content. Our findings highlight that plant identity has stronger influence than fertilization on belowground AM fungal community in this converted pastureland from an alpine meadow.

Endophytic fungi from medicinal plant Bauhinia forficata: Diversity and biotechnological potential.

Science.gov (United States)

Bezerra, Jadson D P; Nascimento, Carlos C F; Barbosa, Renan do N; da Silva, Dianny C V; Svedese, Virgínia M; Silva-Nogueira, Eliane B; Gomes, Bruno S; Paiva, Laura M; Souza-Motta, Cristina M

2015-03-01

Bauhinia forficata is native to South America and used with relative success in the folk medicine in Brazil. The diversity, antibacterial activity, and extracellular hydrolytic enzymes of endophytic fungi associated with this plant were studied. Plant samples, which included leaves, sepals, stems, and seeds, were used. Ninety-five endophytic fungal were isolated (18 from leaves, 22 from sepals, 46 from stems, and nine from seeds), comprising 28 species. The most frequently isolated species were Acremonium curvulum (9.5%), Aspergillus ochraceus (7.37%), Gibberella fujikuroi (10.53%), Myrothecium verrucaria (10.53%) and Trichoderma piluliferum (7.37%). Diversity and species richness were higher in stem tissues, and Sorensen's index of similarity between the tissues was low. Eleven fungi showed antibacterial activity. Aspergillus ochraceus , Gibberella baccata , Penicillium commune , and P. glabrum were those with the greatest antibacterial activity against Staphylococcus aureus and/or Streptococcus pyogenes . Thirteen species showed proteolytic activity, particularly Phoma putaminum . Fourteen species were cellulase positive, particularly the Penicillium species and Myrmecridium schulzeri . All isolates tested were xylanase positive and 10 showed lipolytic activity, especially Penicillium glabrum . It is clear that the endophytic fungi from B. forficata have potential for the production of bioactive compounds and may be a source of new therapeutic agents for the effective treatment of diseases in humans, other animals, and plants. To our knowledge, this is the first study of endophytic fungi from different tissues of B. forficata and their biotechnological potential.

Threats and opportunities of plant pathogenic bacteria.

Science.gov (United States)

Tarkowski, Petr; Vereecke, Danny

2014-01-01

Plant pathogenic bacteria can have devastating effects on plant productivity and yield. Nevertheless, because these often soil-dwelling bacteria have evolved to interact with eukaryotes, they generally exhibit a strong adaptivity, a versatile metabolism, and ingenious mechanisms tailored to modify the development of their hosts. Consequently, besides being a threat for agricultural practices, phytopathogens may also represent opportunities for plant production or be useful for specific biotechnological applications. Here, we illustrate this idea by reviewing the pathogenic strategies and the (potential) uses of five very different (hemi)biotrophic plant pathogenic bacteria: Agrobacterium tumefaciens, A. rhizogenes, Rhodococcus fascians, scab-inducing Streptomyces spp., and Pseudomonas syringae. Copyright © 2013 Elsevier Inc. All rights reserved.

Organic fertilization alters the community composition of root associated fungi in Pisum sativum

DEFF Research Database (Denmark)

Yu, L.; Nicolaisen, M.; Ravnskov, S.

2013-01-01

Organic fertilization is well known to affect individual functional groups of root associated fungi such as arbuscular mycorrhizal (AM) fungi and root pathogens, but limited information is available on the effect of organic fertilization at the fungal community composition level. The main objective...... of the present study was to examine the response of communities of root associated fungi in Pisum sativum to Protamylasse, an organic fertilizer used in pea production. Plants were grown in pots with field soil amended with four different levels of Protamylasse. 454 pyrosequencing was employed to examine......, the organic fertilizer Protamylasse clearly affects communities of root associated fungi, which seems to be linked to the life strategy of the different functional groups of root associated fungi. --------------------------------------------------------------------------------...

Physiological and Molecular Characterization of Biosurfactant Producing Endophytic Fungi Xylaria regalis from the Cones of Thuja plicata as a Potent Plant Growth Promoter with Its Potential Application

Directory of Open Access Journals (Sweden)

Mohd Adnan

2018-01-01

Full Text Available Currently, there is an absolute concern for all nations in agricultural productivity to meet growing demands of human population. In recent time, biosurfactants produced by diverse group of microorganisms are used to achieve such demands as it is known for its ecofriendly use in elimination of plant pathogens and for increasing the bioavailability of nutrients for plants. Endophytic fungi are the important source of secondary metabolites and novel bioactive compounds for different biological applications. In the present study, endophytic fungi Xylaria regalis (X. regalis recovered from the cones of Thuja plicata was evaluated for its biosurfactant producing ability and plant growth-promoting abilities through various screening methods and also via its antagonistic activity against phytopathogens like Fusarium oxysporum and Aspergillus niger. In addition, X. regalis was also tested in vivo for a various range of growth parameters in chilli under greenhouse conditions. Significant increase in shoot and root length, dry matter production of shoot and root, chlorophyll, nitrogen, and phosphorus contents of chilli seedlings was found, which reveals its ability to improve the growth of crop plants. Hence, this study suggests the possibility of biosurfactant producing endophytic fungi X. regalis as a source of novel green biosurfactant for sustainable agriculture to achieve growing demands.

Metagenomic analysis of medicinal Cannabis samples; pathogenic bacteria, toxigenic fungi, and beneficial microbes grow in culture-based yeast and mold tests.

Science.gov (United States)

McKernan, Kevin; Spangler, Jessica; Helbert, Yvonne; Lynch, Ryan C; Devitt-Lee, Adrian; Zhang, Lei; Orphe, Wendell; Warner, Jason; Foss, Theodore; Hudalla, Christopher J; Silva, Matthew; Smith, Douglas R

2016-01-01

Background : The presence of bacteria and fungi in medicinal or recreational Cannabis poses a potential threat to consumers if those microbes include pathogenic or toxigenic species. This study evaluated two widely used culture-based platforms for total yeast and mold (TYM) testing marketed by 3M Corporation and Biomérieux, in comparison with a quantitative PCR (qPCR) approach marketed by Medicinal Genomics Corporation. Methods : A set of 15 medicinal Cannabis samples were analyzed using 3M and Biomérieux culture-based platforms and by qPCR to quantify microbial DNA. All samples were then subjected to next-generation sequencing and metagenomics analysis to enumerate the bacteria and fungi present before and after growth on culture-based media. Results : Several pathogenic or toxigenic bacterial and fungal species were identified in proportions of >5% of classified reads on the samples, including Acinetobacter baumannii, Escherichia coli, Pseudomonas aeruginosa, Ralstonia pickettii, Salmonella enterica, Stenotrophomonas maltophilia, Aspergillus ostianus, Aspergillus sydowii, Penicillium citrinum and Penicillium steckii. Samples subjected to culture showed substantial shifts in the number and diversity of species present, including the failure of Aspergillus species to grow well on either platform. Substantial growth of Clostridium botulinum and other bacteria were frequently observed on one or both of the culture-based TYM platforms. The presence of plant growth promoting (beneficial) fungal species further influenced the differential growth of species in the microbiome of each sample. Conclusions : These findings have important implications for the Cannabis and food safety testing industries.

A plant pathology perspective of fungal genome sequencing.

Science.gov (United States)

Aylward, Janneke; Steenkamp, Emma T; Dreyer, Léanne L; Roets, Francois; Wingfield, Brenda D; Wingfield, Michael J

2017-06-01

The majority of plant pathogens are fungi and many of these adversely affect food security. This mini-review aims to provide an analysis of the plant pathogenic fungi for which genome sequences are publically available, to assess their general genome characteristics, and to consider how genomics has impacted plant pathology. A list of sequenced fungal species was assembled, the taxonomy of all species verified, and the potential reason for sequencing each of the species considered. The genomes of 1090 fungal species are currently (October 2016) in the public domain and this number is rapidly rising. Pathogenic species comprised the largest category (35.5 %) and, amongst these, plant pathogens are predominant. Of the 191 plant pathogenic fungal species with available genomes, 61.3 % cause diseases on food crops, more than half of which are staple crops. The genomes of plant pathogens are slightly larger than those of other fungal species sequenced to date and they contain fewer coding sequences in relation to their genome size. Both of these factors can be attributed to the expansion of repeat elements. Sequenced genomes of plant pathogens provide blueprints from which potential virulence factors were identified and from which genes associated with different pathogenic strategies could be predicted. Genome sequences have also made it possible to evaluate adaptability of pathogen genomes and genomic regions that experience selection pressures. Some genomic patterns, however, remain poorly understood and plant pathogen genomes alone are not sufficient to unravel complex pathogen-host interactions. Genomes, therefore, cannot replace experimental studies that can be complex and tedious. Ultimately, the most promising application lies in using fungal plant pathogen genomics to inform disease management and risk assessment strategies. This will ultimately minimize the risks of future disease outbreaks and assist in preparation for emerging pathogen outbreaks.

In vitro antimicrobial activity of plant extracts of Avicennia alba against some important pathogens

Directory of Open Access Journals (Sweden)

Varahalarao Vadlapudi

2012-05-01

Full Text Available Objective: In this present study antimicrobial activity of aerial parts of Avicennia alba were evaluated against the resistant pathogens belong to aquatic, human and plant origin. Methods: Soxhlet extraction method was used to get the corresponding extracts of hexane, chloroform and methanol. The antimicrobial activities of the organic solvent extracts on the various test microorganisms, including bacteria and fungi investigated using agar well diffusion technique. The length of inhibition zone was measured in millimeters from the edge of the well to the edge of the inhibition zone. Methanol and chloroform extracts exhibited promising antimicrobial activity than hexane extracts. Results: The zone of inhibition of chloroform varies from (9 to 17 mm where as with methanol (11 to 28 mm at 100 mg/ml concentration. Among all microorganisms studied Erwinia caratovara and Pseudomonas syringae showed the considerable growth inhibition with chloroform and methanolic extracts. Conclusions: A. alba can be used in the treatment of infectious diseases caused by resistant pathogenic microorganisms. Further studies are being carried out in order to separate the individual components that are present in plant extracts of A. alba using column chromatography.

Profiling the extended phenotype of plant pathogens: Challenges in Bacterial Molecular Plant Pathology.

Science.gov (United States)

Preston, Gail M

2017-04-01

One of the most fundamental questions in plant pathology is what determines whether a pathogen grows within a plant? This question is frequently studied in terms of the role of elicitors and pathogenicity factors in the triggering or overcoming of host defences. However, this focus fails to address the basic question of how the environment in host tissues acts to support or restrict pathogen growth. Efforts to understand this aspect of host-pathogen interactions are commonly confounded by several issues, including the complexity of the plant environment, the artificial nature of many experimental infection systems and the fact that the physiological properties of a pathogen growing in association with a plant can be very different from the properties of the pathogen in culture. It is also important to recognize that the phenotype and evolution of pathogen and host are inextricably linked through their interactions, such that the environment experienced by a pathogen within a host, and its phenotype within the host, is a product of both its interaction with its host and its evolutionary history, including its co-evolution with host plants. As the phenotypic properties of a pathogen within a host cannot be defined in isolation from the host, it may be appropriate to think of pathogens as having an 'extended phenotype' that is the product of their genotype, host interactions and population structure within the host environment. This article reflects on the challenge of defining and studying this extended phenotype, in relation to the questions posed below, and considers how knowledge of the phenotype of pathogens in the host environment could be used to improve disease control. What determines whether a pathogen grows within a plant? What aspects of pathogen biology should be considered in describing the extended phenotype of a pathogen within a host? How can we study the extended phenotype in ways that provide insights into the phenotypic properties of pathogens

Nonhost resistance to rust pathogens - a continuation of continua.

Science.gov (United States)

Bettgenhaeuser, Jan; Gilbert, Brian; Ayliffe, Michael; Moscou, Matthew J

2014-01-01

The rust fungi (order: Pucciniales) are a group of widely distributed fungal plant pathogens, which can infect representatives of all vascular plant groups. Rust diseases significantly impact several crop species and considerable research focuses on understanding the basis of host specificity and nonhost resistance. Like many pathogens, rust fungi vary considerably in the number of hosts they can infect, such as wheat leaf rust (Puccinia triticina), which can only infect species in the genera Triticum and Aegilops, whereas Asian soybean rust (Phakopsora pachyrhizi) is known to infect over 95 species from over 42 genera. A greater understanding of the genetic basis determining host range has the potential to identify sources of durable resistance for agronomically important crops. Delimiting the boundary between host and nonhost has been complicated by the quantitative nature of phenotypes in the transition between these two states. Plant-pathogen interactions in this intermediate state are characterized either by (1) the majority of accessions of a species being resistant to the rust or (2) the rust only being able to partially complete key components of its life cycle. This leads to a continuum of disease phenotypes in the interaction with different plant species, observed as a range from compatibility (host) to complete immunity within a species (nonhost). In this review we will highlight how the quantitative nature of disease resistance in these intermediate interactions is caused by a continuum of defense barriers, which a pathogen needs to overcome for successfully establishing itself in the host. To illustrate continua as this underlying principle, we will discuss the advances that have been made in studying nonhost resistance towards rust pathogens, particularly cereal rust pathogens.

Diversity and taxonomy of endophytic xylariaceous fungi from medicinal plants of Dendrobium (Orchidaceae).

Science.gov (United States)

Chen, Juan; Zhang, Li-Chun; Xing, Yong-Mei; Wang, Yun-Qiang; Xing, Xiao-Ke; Zhang, Da-Wei; Liang, Han-Qiao; Guo, Shun-Xing

2013-01-01

Dendrobium spp. are traditional Chinese medicinal plants, and the main effective ingredients (polysaccharides and alkaloids) have pharmacologic effects on gastritis infection, cancer, and anti-aging. Previously, we confirmed endophytic xylariaceous fungi as the dominant fungi in several Dendrobium species of tropical regions from China. In the present study, the diversity, taxonomy, and distribution of culturable endophytic xylariaceous fungi associated with seven medicinal species of Dendrobium (Orchidaceae) were investigated. Among the 961 endophytes newly isolated, 217 xylariaceous fungi (morphotaxa) were identified using morphological and molecular methods. The phylogenetic tree constructed using nuclear ribosomal internal transcribed spacer (ITS), large subunit of ribosomal DNA (LSU), and beta-tubulin sequences divided these anamorphic xylariaceous isolates into at least 18 operational taxonomic units (OTUs). The diversity of the endophytic xylariaceous fungi in these seven Dendrobium species was estimated using Shannon and evenness indices, with the results indicating that the dominant Xylariaceae taxa in each Dendrobium species were greatly different, though common xylariaceous fungi were found in several Dendrobium species. These findings implied that different host plants in the same habitats exhibit a preference and selectivity for their fungal partners. Using culture-dependent approaches, these xylariaceous isolates may be important sources for the future screening of new natural products and drug discovery.

Arbuscular mycorrhizal fungi alter phosphorus relations of broomsedge (Andropogon virginicus L.) plants

Energy Technology Data Exchange (ETDEWEB)

Ning, J.C.; Cumming, J.R.

2001-07-01

Broomsedge (Andropogon virginicus L.) is a dominant grass revegetating many abandoned coal-mined lands in West Virginia, USA. Residual soils on such sites are often characterized by low pH, low nutrients, and high aluminium. Experiments were conducted to assess the resistance of broomsedge to limited phosphorus (Pi) availability and to investigate the role that arbuscular mycorrhizal (AM) fungi play in aiding plant growth under low Pi conditions. Pregerminated mycorrhizal and non-mycorrhizal seedlings were grown in a sand-culture system with nutrient solutions containing Pi concentrations ranging from 10 to 100 {mu}M for 8 weeks. Non-mycorrhizal plants exhibited severe inhibition of growth under Pi limitation ({lt}60 {mu}M). Colonization by AM fungi greatly enhanced host plant growth at low Pi concentrations, but did not benefit growth when Pi was readily available (100 {mu}M). In comparison to non-mycorrhizal plants, mycorrhizal plants had higher phosphorus use efficiency at low Pi concentrations and maintained nearly constant tissue nutrient concentrations across the gradient of Pi concentrations investigated. Manganese (Mn) and sodium (Na) accumulated in shoots of nonmycorrhizal plants under Pi limitation. Mycorrhizal plants exhibited lower instantaneous Pi uptake rates and significantly lower C-min values compared to non-mycorrhizal plants. These patterns suggest that the symbiotic association between broomsedge roots and AM fungi effectively maintains nutrient homeostasis through changes in physiological properties, including nutrient uptake, allocation and use. The mycorrhizal association is thus a major adaptation that allows broomsedge to become established on infertile mined lands.

Multiplex detection of plant pathogens using a microsphere immunoassay technology.

Directory of Open Access Journals (Sweden)

Ratthaphol Charlermroj

Full Text Available Plant pathogens are a serious problem for seed export, plant disease control and plant quarantine. Rapid and accurate screening tests are urgently required to protect and prevent plant diseases spreading worldwide. A novel multiplex detection method was developed based on microsphere immunoassays to simultaneously detect four important plant pathogens: a fruit blotch bacterium Acidovorax avenae subsp. citrulli (Aac, chilli vein-banding mottle virus (CVbMV, potyvirus, watermelon silver mottle virus (WSMoV, tospovirus serogroup IV and melon yellow spot virus (MYSV, tospovirus. An antibody for each plant pathogen was linked on a fluorescence-coded magnetic microsphere set which was used to capture corresponding pathogen. The presence of pathogens was detected by R-phycoerythrin (RPE-labeled antibodies specific to the pathogens. The assay conditions were optimized by identifying appropriate antibody pairs, blocking buffer, concentration of RPE-labeled antibodies and assay time. Once conditions were optimized, the assay was able to detect all four plant pathogens precisely and accurately with substantially higher sensitivity than enzyme-linked immunosorbent assay (ELISA when spiked in buffer and in healthy watermelon leaf extract. The assay time of the microsphere immunoassay (1 hour was much shorter than that of ELISA (4 hours. This system was also shown to be capable of detecting the pathogens in naturally infected plant samples and is a major advancement in plant pathogen detection.

Multiplex detection of plant pathogens using a microsphere immunoassay technology.

Science.gov (United States)

Charlermroj, Ratthaphol; Himananto, Orawan; Seepiban, Channarong; Kumpoosiri, Mallika; Warin, Nuchnard; Oplatowska, Michalina; Gajanandana, Oraprapai; Grant, Irene R; Karoonuthaisiri, Nitsara; Elliott, Christopher T

2013-01-01

Plant pathogens are a serious problem for seed export, plant disease control and plant quarantine. Rapid and accurate screening tests are urgently required to protect and prevent plant diseases spreading worldwide. A novel multiplex detection method was developed based on microsphere immunoassays to simultaneously detect four important plant pathogens: a fruit blotch bacterium Acidovorax avenae subsp. citrulli (Aac), chilli vein-banding mottle virus (CVbMV, potyvirus), watermelon silver mottle virus (WSMoV, tospovirus serogroup IV) and melon yellow spot virus (MYSV, tospovirus). An antibody for each plant pathogen was linked on a fluorescence-coded magnetic microsphere set which was used to capture corresponding pathogen. The presence of pathogens was detected by R-phycoerythrin (RPE)-labeled antibodies specific to the pathogens. The assay conditions were optimized by identifying appropriate antibody pairs, blocking buffer, concentration of RPE-labeled antibodies and assay time. Once conditions were optimized, the assay was able to detect all four plant pathogens precisely and accurately with substantially higher sensitivity than enzyme-linked immunosorbent assay (ELISA) when spiked in buffer and in healthy watermelon leaf extract. The assay time of the microsphere immunoassay (1 hour) was much shorter than that of ELISA (4 hours). This system was also shown to be capable of detecting the pathogens in naturally infected plant samples and is a major advancement in plant pathogen detection.

Fungi treated with small chemicals exhibit increased antimicrobial activity against facultative bacterial and yeast pathogens.

Science.gov (United States)

Zutz, Christoph; Bandian, Dragana; Neumayer, Bernhard; Speringer, Franz; Gorfer, Markus; Wagner, Martin; Strauss, Joseph; Rychli, Kathrin

2014-01-01

For decades, fungi have been the main source for the discovery of novel antimicrobial drugs. Recent sequencing efforts revealed a still high number of so far unknown "cryptic" secondary metabolites. The production of these metabolites is presumably epigenetically silenced under standard laboratory conditions. In this study, we investigated the effect of six small mass chemicals, of which some are known to act as epigenetic modulators, on the production of antimicrobial compounds in 54 spore forming fungi. The antimicrobial effect of fungal samples was tested against clinically facultative pathogens and multiresistant clinical isolates. In total, 30 samples of treated fungi belonging to six different genera reduced significantly growth of different test organisms compared to the untreated fungal sample (growth log reduction 0.3-4.3). For instance, the pellet of Penicillium restrictum grown in the presence of butyrate revealed significant higher antimicrobial activity against Staphylococcus (S.) aureus and multiresistant S. aureus strains and displayed no cytotoxicity against human cells, thus making it an ideal candidate for antimicrobial compound discovery. Our study shows that every presumable fungus, even well described fungi, has the potential to produce novel antimicrobial compounds and that our approach is capable of rapidly filling the pipeline for yet undiscovered antimicrobial substances.

Antifungal Rhizosphere Bacteria Can increase as Response to the Presence of Saprotrophic Fungi.

Directory of Open Access Journals (Sweden)

Wietse de Boer

Full Text Available Knowledge on the factors that determine the composition of bacterial communities in the vicinity of roots (rhizosphere is essential to understand plant-soil interactions. Plant species identity, plant growth stage and soil properties have been indicated as major determinants of rhizosphere bacterial community composition. Here we show that the presence of saprotrophic fungi can be an additional factor steering rhizosphere bacterial community composition and functioning. We studied the impact of presence of two common fungal rhizosphere inhabitants (Mucor hiemalis and Trichoderma harzianum on the composition of cultivable bacterial communities developing in the rhizosphere of Carex arenaria (sand sedge in sand microcosms. Identification and phenotypic characterization of bacterial isolates revealed clear shifts in the rhizosphere bacterial community composition by the presence of two fungal strains (M. hiemalis BHB1 and T. harzianum PvdG2, whereas another M. hiemalis strain did not show this effect. Presence of both M. hiemalis BHB1 and T. harzianum PvdG2 resulted in a significant increase of chitinolytic and (in vitro antifungal bacteria. The latter was most pronounced for M. hiemalis BHB1, an isolate from Carex roots, which stimulated the development of the bacterial genera Achromobacter and Stenotrophomonas. In vitro tests showed that these genera were strongly antagonistic against M. hiemalis but also against the plant-pathogenic fungus Rhizoctonia solani. The most likely explanation for fungal-induced shifts in the composition of rhizosphere bacteria is that bacteria are being selected which are successful in competing with fungi for root exudates. Based on the results we propose that measures increasing saprotrophic fungi in agricultural soils should be explored as an alternative approach to enhance natural biocontrol against soil-borne plant-pathogenic fungi, namely by stimulating indigenous antifungal rhizosphere bacteria.

Influence of mycorrhizal fungi on fate of E. coli O157:H7 and Salmonella in soil and internalization into Romaine lettuce plants.

Science.gov (United States)

Nicholson, April M; Gurtler, Joshua B; Bailey, Rebecca B; Niemira, Brendan A; Douds, David D

2015-01-02

The objectives of this study were to determine the influence of a symbiotic arbuscular mycorrhizal (AM) fungus on persistence of Salmonella and enterohemorrhagic Escherichia coli O157:H7 (EHEC) within soil, and survival within Romaine lettuce. Romaine seedlings were grown with or without AM fungi. Soil surrounding plants was inoculated with ca. 8 log CFU/plant of either Salmonella enterica or E. coli EHEC composites. Samples (soil, root, and shoot) were analyzed on days 1, 8, 15 and 22 for Salmonella and EHEC by direct plating and selective enrichment. Twenty-four hours after inoculation, populations of Salmonella and EHEC, respectively, were 4.20 and 3.24 log CFU/root, 2.52 and 1.17 log CFU/shoot, and 5.46 and 5.17 log CFU/g soil. By selective enrichment, samples tested positive for Salmonella or EHEC at day 22 at rates of 94 and 68% (shoot), 97 and 56% (root), and 100 and 75% (soil), respectively, suggesting that Salmonella has a greater propensity for survival than EHEC. Salmonella populations in soil remained as high as 4.35 log CFU/g by day 22, while EHEC populations dropped to 1.12 log CFU/g in the same amount of time. Ninety-two percent of all Romaine leaves in our study were positive for internalized Salmonella from days 8 to 22 and remained as high as 1.26 log CFU/shoot on day 22 in AM fungi+Romaine plants. There were no differences (P>0.05) between the survival of either pathogen based on the presence or absence of mycorrhizal fungi. Results of this study suggest that AM fungi do not affect the internalization and/or survival of either S. enterica or E. coli O157:H7 in Romaine lettuce seedlings. Our results should provide Romaine lettuce farmers confidence that the presence and/or application of AM fungi to crop soil is not a contributing factor to the internalization and survival of Salmonella or E. coli O157:H7 within Romaine lettuce plants. Published by Elsevier B.V.

Pathogenic fungi and parasitoids of aphids present in air captures of migratory alates in the low-latitude plateau of Yunnan, China.

Science.gov (United States)

Huang, Zhi-Hong; Feng, Ming-Guang; Chen, Xue-Xin; Liu, Shu-Sheng

2008-10-01

To survey fungal pathogens and parasitoids of aphids in the low-latitude plateau of Yunnan, southwest China, 3,553 migratory alates of Brevicoryne brassicae, Lipaphis erysimi, and Myzus persicae were attracted to a yellow-plus-plant trap from air during a full-year period and individually reared on cabbage leaves for 7-14 d at 18-22 degrees C and L:D 12:12. Among the trapped alates, 19.2% were killed by 10 species of aphid-pathogenic fungi after survival of 2.3 d (range, 1-7 d). Another 2.8% were mummified by the wasps Aphidius gifuensis, Diaeretella rapae, Ephedrus plagiator, and Aphelinus mali after survival of 4.9 d (range, 1-11 d). Most of the mycosed alates (77.8%) died from Entomophthorales predominated by Pandora neoaphidis (42.7%) and Zoophthora radicans (14.5%), followed by P. nouryi, Neozygites fresenii, Conidiobiolus spp., Entomophthora planchoniana, and Z. aphidis in decreasing frequencies. A mitosporic fungus, Lecanicillium lecanii, was found frequently in L. erysimi alates trapped in rainy season. However, B. brassicae alates captured in dry season were infected or parasitized very occasionally. The predeath fecundity of the infected or parasitized alates warranted successful colonization on plants, although greatly reduced, and was well shown by the fitted probability for a given fecundity per capita and the increasing mean size of their progeny colonies. Contagious transmission of the alate-borne mycosis in most of the colonies caused high progeny mortalities within 14 d. The results highlight for the first time the diversity of aphid pathogens and the spread of both pathogens and parasitoids with host dispersal flight in the low-latitude plateau.

Specific recognition of fungal pathogens by plants

International Nuclear Information System (INIS)

Knogge, W.; Gierlich, A.; Max-Planck-Institute for Plant Breeding,; Van't Slot, K.A.E.; Papavoine, T.

2001-01-01

Full text: Induction of plant defence reactions and, hence, genotype-specific disease resistance results from the interaction of highly specific plant resistance (R) genes with matching pathogen avirulence (Avr) genes (gene-for-gene interactions). More than thirty R genes acting against different types of pathogens (viruses, bacteria, fungi, oomycetes, nematodes) have been isolated from various plants species. However, with few exceptions it remains to be shown how their products recognise the complementary Avr gene products. To date, Avr genes and their products have been characterised from only three fungal species. These include the NIP1 gene from Rhynchosporium secalis, the causal agent of barley leaf scald. It encodes a small, secreted protein, NIP1, that triggers defence reactions exclusively in barley cultivars expressing the R gene Rrs1. NIP1 also non-specifically stimulates the H + -ATPase activity in barley plasma membranes, suggesting that the host recognition system targets a putative fungal virulence factor. Virulent fungal strains lack the gene or carry an allele encoding a non-functional product. Four NIP1 iso-forms have been characterised; NIP1-I and NIP1-II although both elicitor-active display different levels of activity, whereas the isoforms NIP1-III and NIP1-IV are inactive. After establishing a heterologous expression system, the single amino acids specifying NIP1-III and NIP1-IV were integrated into the NIP1-I sequence and yielded the inactive mutant proteins NIP1-III* and NIP1-IV*. The elicitor-inactive isoforms were also unable to stimulate the H + -ATPase, suggesting that both functions of NIP1 are mediated by a single plant receptor. The 3D structure of NIP1-I has been elucidated by 1 H- and 15 N-NMR spectroscopy. Binding studies using 125 I-NIP1-I revealed a single class of high-affinity binding sites on membranes from both Rrs1- and rrs1-cultivars, suggesting that NIP1-binding is not sufficient for defence triggering and that an

List of New Names of Plant Pathogenic Bacteria (2008-2010)

Science.gov (United States)

In 2010 the International Society of Plant Pathology Committee on the Taxonomy of Plant Pathogenic Bacteria published the Comprehensive List of Names of Plant Pathogenic Bacteria, 1980-2007 to provide an authoritative register of names of plant pathogens. In this manuscript we up-date the list of na...

Plant pathology: monitoring a pathogen-targeted host protein.

Science.gov (United States)

Ellis, Jeff; Dodds, Peter

2003-05-13

A plant protein RIN4 is targeted and modified by bacterial pathogens as part of the disease process. At least two host resistance proteins monitor this pathogen interference and trigger the plant's defence responses.

An efficient method for DNA extraction from Cladosporioid fungi.

Science.gov (United States)

Moslem, M A; Bahkali, A H; Abd-Elsalam, K A; Wit, P J G M

2010-11-23

We developed an efficient method for DNA extraction from Cladosporioid fungi, which are important fungal plant pathogens. The cell wall of Cladosporioid fungi is often melanized, which makes it difficult to extract DNA from their cells. In order to overcome this we grew these fungi for three days on agar plates and extracted DNA from mycelium mats after manual or electric homogenization. High-quality DNA was isolated, with an A(260)/A(280) ratio ranging between 1.6 and 2.0. Isolated genomic DNA was efficiently digested with restriction enzymes and produced distinct banding patterns on agarose gels for the different Cladosporium species. Clear DNA fragments from the isolated DNA were amplified by PCR using small and large subunit rDNA primers, demonstrating that this method provides DNA of sufficiently high quality for molecular analyses.

Fungi that Infect Humans.

Science.gov (United States)

Köhler, Julia R; Hube, Bernhard; Puccia, Rosana; Casadevall, Arturo; Perfect, John R

2017-06-01

Fungi must meet four criteria to infect humans: growth at human body temperatures, circumvention or penetration of surface barriers, lysis and absorption of tissue, and resistance to immune defenses, including elevated body temperatures. Morphogenesis between small round, detachable cells and long, connected cells is the mechanism by which fungi solve problems of locomotion around or through host barriers. Secretion of lytic enzymes, and uptake systems for the released nutrients, are necessary if a fungus is to nutritionally utilize human tissue. Last, the potent human immune system evolved in the interaction with potential fungal pathogens, so few fungi meet all four conditions for a healthy human host. Paradoxically, the advances of modern medicine have made millions of people newly susceptible to fungal infections by disrupting immune defenses. This article explores how different members of four fungal phyla use different strategies to fulfill the four criteria to infect humans: the Entomophthorales, the Mucorales, the Ascomycota, and the Basidiomycota. Unique traits confer human pathogenic potential on various important members of these phyla: pathogenic Onygenales comprising thermal dimorphs such as Histoplasma and Coccidioides ; the Cryptococcus spp. that infect immunocompromised as well as healthy humans; and important pathogens of immunocompromised patients- Candida , Pneumocystis , and Aspergillus spp. Also discussed are agents of neglected tropical diseases important in global health such as mycetoma and paracoccidiomycosis and common pathogens rarely implicated in serious illness such as dermatophytes. Commensalism is considered, as well as parasitism, in shaping genomes and physiological systems of hosts and fungi during evolution.

Nonhost resistance to rust pathogens – a continuation of continua

Directory of Open Access Journals (Sweden)

Jan eBettgenhaeuser

2014-12-01

Full Text Available The rust fungi (order: Pucciniales are a group of widely distributed fungal plant pathogens, which can infect representatives of all vascular plant groups. Rust diseases significantly impact several crop species and considerable research focuses on understanding the basis of host specificity and nonhost resistance. Like many pathogens, rust fungi vary considerably in the number of hosts they can infect, such as wheat leaf rust (Puccinia triticina, which can only infect species in the genera Triticum and Aegilops, whereas Asian soybean rust (Phakopsora pachyrhizi is known to infect over 95 species from over 42 genera. A greater understanding of the genetic basis determining host range has the potential to identify sources of durable resistance for agronomically important crops. Delimiting the boundary between host and nonhost has been complicated by the quantitative nature of phenotypes in the transition between these two states. Plant-pathogen interactions in this intermediate state are characterized either by (1 the majority of accessions of a species being resistant to the rust or (2 the rust only being able to partially complete key components of its life cycle. This leads to a continuum of disease phenotypes in the interaction with different plant species, observed as a range from compatibility (host to complete immunity within a species (nonhost. In this review we will highlight how the quantitative nature of disease resistance in these intermediate interactions is caused by a continuum of defense barriers, which a pathogen needs to overcome for successfully establishing itself in the host. To illustrate continua as this underlying principle, we will discuss the advances that have been made in studying nonhost resistance towards rust pathogens, particularly cereal rust pathogens.

Proposals to clarify and enhance the naming of fungi under the International Code of Nomenclature for algae, fungi, and plants.

Science.gov (United States)

Hawksworth, David L

2015-06-01

Twenty-three proposals to modify the International Code of Nomenclature for algae, fungi, and plants adopted in 2011 with respect to the provisions for fungi are made, in accordance with the wishes of mycologists expressed at the 10(th) International Mycological Congress in Bangkok in 2014, and with the support of the International Commission on the Taxonomy of Fungi (ICTF), the votes of which are presented here. The proposals relate to: conditions for epitypification, registration of later typifications, protected lists of names, removal of exemptions for lichen-forming fungi, provision of a diagnosis when describing a new taxon, citation of sanctioned names, avoiding homonyms in other kingdoms, ending preference for sexually typified names, and treatment of conspecific names with the same epithet. These proposals are also being published in Taxon, will be considered by the Nomenclature Committee for Fungi and General Committee on Nomenclature, and voted on at the 19(th) International Botanical Congress in Shenzhen, China, in 2017.

Plant-Polysaccharide-Degrading Enzymes from Basidiomycetes

Science.gov (United States)

Rytioja, Johanna; Hildén, Kristiina; Yuzon, Jennifer; Hatakka, Annele; de Vries, Ronald P.

2014-01-01

SUMMARY Basidiomycete fungi subsist on various types of plant material in diverse environments, from living and dead trees and forest litter to crops and grasses and to decaying plant matter in soils. Due to the variation in their natural carbon sources, basidiomycetes have highly varied plant-polysaccharide-degrading capabilities. This topic is not as well studied for basidiomycetes as for ascomycete fungi, which are the main sources of knowledge on fungal plant polysaccharide degradation. Research on plant-biomass-decaying fungi has focused on isolating enzymes for current and future applications, such as for the production of fuels, the food industry, and waste treatment. More recently, genomic studies of basidiomycete fungi have provided a profound view of the plant-biomass-degrading potential of wood-rotting, litter-decomposing, plant-pathogenic, and ectomycorrhizal (ECM) basidiomycetes. This review summarizes the current knowledge on plant polysaccharide depolymerization by basidiomycete species from diverse habitats. In addition, these data are compared to those for the most broadly studied ascomycete genus, Aspergillus, to provide insight into specific features of basidiomycetes with respect to plant polysaccharide degradation. PMID:25428937

Plant Pathogenicity in Spaceflight Environments

OpenAIRE

Bishop, Deborah L.; Levine, Howard G.; Anderson, Anne J.

1996-01-01

Plants grown in microgravity are subject to many environmental stresses, which may promote microbial growth and result in pathogenicity to the plant. Recent plant experiments with super dwarf wheat aboard the NASA Space Shuttle and NASA/Russian Mir Space Station returned from the mission with severe degrees of fungal contamination. Understanding the cause of such microbial contamination and methods to eliminate it are necessary prerequisites for continued plant growth and development studies ...

Effect of arbuscular mycorrhizal (AM) fungi on 137Cs uptake by plants grown on different soils

International Nuclear Information System (INIS)

Vinichuk, M.; Mårtensson, A.; Ericsson, T.; Rosén, K.

2013-01-01

The potential use of mycorrhiza as a bioremediation agent for soils contaminated by radiocesium was evaluated in a greenhouse experiment. The uptake of 137 Cs by cucumber, perennial ryegrass, and sunflower after inoculation with a commercial arbuscular mycorrhizal (AM) product in soils contaminated with 137 Cs was investigated, with non-mycorrhizal quinoa included as a “reference” plant. The effect of cucumber and ryegrass inoculation with AM fungi on 137 Cs uptake was inconsistent. The effect of AM fungi was most pronounced in sunflower: both plant biomass and 137 Cs uptake increased on loamy sand and loamy soils. The total 137 Cs activity accumulated within AM host sunflower on loamy sand and loamy soils was 2.4 and 3.2-fold higher than in non-inoculated plants. Although the enhanced uptake of 137 Cs by quinoa plants on loamy soil inoculated by the AM fungi was observed, the infection of the fungi to the plants was not confirmed. - Highlights: ► Effect of soil inoculation on 137 Cs uptake by crops was studied in greenhouse. ► 137 Cs uptake by inoculated sunflower plants was most pronounced. ► The higher 137 Cs uptake by inoculated sunflower due to presence of mycorrhiza. ► Studies suggest potential for use of mycorrhiza on contaminated sites.

Correlation of Soil Environmental to Diversity the Entomopathogenic Fungi

Directory of Open Access Journals (Sweden)

Rose Novita Sari Handoko

2017-01-01

Full Text Available Ecosystem rice fields that have high diversity, able to control the pest. Habitat entomopathogenic fungi in the soil have been examined on cabbage plants but has not been reported in the rice field. The study was conducted through surveys of crops and paddy fields by the application of IPM in Kasembon Malang. A total of 5 points soil samples were determined diagonally used in this study. Isolation of entomopathogenic fungi from the rhizosphere of paddy is done by plate dilution method. Entomopathogenic fungi were identified to genus level by observing the macroscopic and microscopic characteristics. Koch's postulates done on Tenebrio molitor, then observe the symptoms and mortality of Spodoptera litura time pathogenicity test. The results showed that the genus of entomopathogenic fungi in the rhizosphere of rice is Penicillium sp., Aspergillus sp. and has not been identified. Chemical analysis of soil for pH is 4.00 to 5.00. Soil organic matter is 1.89% to 3.20%.   Keywords: diversity, entomopathogenic fungi, integrated pest management, rhizosphere

The role of onion-associated fungi in bulb mite infestation and damage to onion seedlings.

Science.gov (United States)

Ofek, Tal; Gal, Shira; Inbar, Moshe; Lebiush-Mordechai, Sara; Tsror, Leah; Palevsky, Eric

2014-04-01

In Israel Rhizoglyphus robini is considered to be a pest in its own right, even though the mite is usually found in association with fungal pathogens. Plant protection recommendations are therefore to treat germinating onions seedlings, clearly a crucial phase in crop production, when mites are discovered. The aim of this study was to determine the role of fungi in bulb mite infestation and damage to germinating onion seedlings. Accordingly we (1) evaluated the effect of the mite on onion seedling germination and survival without fungi, (2) compared the attraction of the mite to species and isolates of various fungi, (3) assessed the effect of a relatively non-pathogenic isolate of Fusarium oxysporum on mite fecundity, and (4) determined the effects of the mite and of F. oxysporum separately and together, on onion seedling germination and sprout development. A significant reduction of seedling survival was recorded only in the 1,000 mites/pot treatment, after 4 weeks. Mites were attracted to 6 out of 7 collected fungi isolates. Mite fecundity on onion sprouts infested with F. oxysporum was higher than on non-infested sprouts. Survival of seedlings was affected by mites, fungi, and their combination. Sprouts on Petri dishes after 5 days were significantly longer in the control and mite treatments than both fungi treatments. During the 5-day experiment more mites were always found on the fungi-infected sprouts than on the non-infected sprouts. Future research using suppressive soils to suppress soil pathogens and subsequent mite damage is proposed.

Thermophillic and thermotolerant fungi isolated from the thermal effluent of nuclear power generating reactors

International Nuclear Information System (INIS)

Rippon, J.W.; Gerhold, R.; Heath, M.

1980-01-01

Over a period of a year, samples of water, foam, microbial mat, soil and air were obtained from areas associated with the cooling canal of a nuclear power station. The seventeen sample sites included water in the cooling canal that was thermally enriched and soil and water adjacent to, up-stream, downstream and at a distance from the generator. Air samples were taken at the plant and at various disstances from the plant. Fifty-two species of thermotolerant and thermophilic fungi were isolated. Of these, eleven species are grouped as opportunistic Mucorales or opportunistic Aspergillus sp. One veterinary pathogen was also isolated (Dactylaria gallopara). The opportunistic/pathogenic fungi were found primarily in the intake bay, the discharge bay and the cooling canal. Smaller numbers were obtained at both upstream and downstream locations. Soil samples near the cooling canal reflected an enrichment of thermophilous organisms, the previously mentioned opportunistic Mucorales and Aspergillus spp. Their numbers were found to be greater than that usually encountered in a mesophilic environment. However, air and soil samples taken at various distances from the power station indicated no greater abundance of these thermophilous fungi than would be expected from a thermal enriched environment. Our results indicate that there was no significant dissemination of thermophilous fungi from the thermal enriched effluents to the adjacent environment. These findings are consistent with the results of other investigators. (orig.)

Plant-symbiotic fungi as chemical engineers: multi-genome analysis of the clavicipitaceae reveals dynamics of alkaloid loci.

Directory of Open Access Journals (Sweden)

Christopher L Schardl

Full Text Available The fungal family Clavicipitaceae includes plant symbionts and parasites that produce several psychoactive and bioprotective alkaloids. The family includes grass symbionts in the epichloae clade (Epichloë and Neotyphodium species, which are extraordinarily diverse both in their host interactions and in their alkaloid profiles. Epichloae produce alkaloids of four distinct classes, all of which deter insects, and some-including the infamous ergot alkaloids-have potent effects on mammals. The exceptional chemotypic diversity of the epichloae may relate to their broad range of host interactions, whereby some are pathogenic and contagious, others are mutualistic and vertically transmitted (seed-borne, and still others vary in pathogenic or mutualistic behavior. We profiled the alkaloids and sequenced the genomes of 10 epichloae, three ergot fungi (Claviceps species, a morning-glory symbiont (Periglandula ipomoeae, and a bamboo pathogen (Aciculosporium take, and compared the gene clusters for four classes of alkaloids. Results indicated a strong tendency for alkaloid loci to have conserved cores that specify the skeleton structures and peripheral genes that determine chemical variations that are known to affect their pharmacological specificities. Generally, gene locations in cluster peripheries positioned them near to transposon-derived, AT-rich repeat blocks, which were probably involved in gene losses, duplications, and neofunctionalizations. The alkaloid loci in the epichloae had unusual structures riddled with large, complex, and dynamic repeat blocks. This feature was not reflective of overall differences in repeat contents in the genomes, nor was it characteristic of most other specialized metabolism loci. The organization and dynamics of alkaloid loci and abundant repeat blocks in the epichloae suggested that these fungi are under selection for alkaloid diversification. We suggest that such selection is related to the variable life histories

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

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

Networks Depicting the Fine-Scale Co-Occurrences of Fungi in Soil Horizons.

Science.gov (United States)

Toju, Hirokazu; Kishida, Osamu; Katayama, Noboru; Takagi, Kentaro

2016-01-01

Fungi in soil play pivotal roles in nutrient cycling, pest controls, and plant community succession in terrestrial ecosystems. Despite the ecosystem functions provided by soil fungi, our knowledge of the assembly processes of belowground fungi has been limited. In particular, we still have limited knowledge of how diverse functional groups of fungi interact with each other in facilitative and competitive ways in soil. Based on the high-throughput sequencing data of fungi in a cool-temperate forest in northern Japan, we analyzed how taxonomically and functionally diverse fungi showed correlated fine-scale distributions in soil. By uncovering pairs of fungi that frequently co-occurred in the same soil samples, networks depicting fine-scale co-occurrences of fungi were inferred at the O (organic matter) and A (surface soil) horizons. The results then led to the working hypothesis that mycorrhizal, endophytic, saprotrophic, and pathogenic fungi could form compartmentalized (modular) networks of facilitative, antagonistic, and/or competitive interactions in belowground ecosystems. Overall, this study provides a research basis for further understanding how interspecific interactions, along with sharing of niches among fungi, drive the dynamics of poorly explored biospheres in soil.

Entomopathogenic fungi as biological controllers: New insights into their virulence and pathogenicity

Directory of Open Access Journals (Sweden)

Shahid Ali Ahmad

2012-01-01

Full Text Available Entomopathogenic fungi vary considerably in their mode of action and virulence. Successful infection depends primarily on the adherence and penetration ability of a fungus to the host integuments. A variety of extracellular enzymes is produced during the degradation of insect integument. The attempts to control insects have changed over time from chemicals to natural control methods. This is why the development of natural methods of insect control or biopesticides, is preferred. By the use of fungal entomopathogens, insect pests can be controlled. There is no doubt that insects have been used for many years, but their effective use in the field remains elusive. However, their additional role in nature has also been discovered. Comparison of entomopathogens with conventional chemical pesticides depends on their efficiency and cost. In addition to efficiency, there are advantages in using microbial control agents, such as human safety and other non-target organisms; pesticide residues are minimized in food and biodiversity increased in managed ecosystems. In the present review the pathogenicity and virulence of entomopathogenic fungi and their role as biological control agents using biotechnology will be discussed.

Ecological plasticity of Trichoderma fungi in leached chernozem

Science.gov (United States)

Svistova, I. D.; Senchakova, T. Yu.

2010-03-01

The autecological properties of Trichoderma fungi ecotypes isolated from the leached chernozem of the forest-steppe zone of the European part of Russia have been studied. We were the first who carried out the complex study of the synecological relations of micromycetes of such kinds in a system including the soil, microbial community, and plants, i.e., their relations with soil saprotrophic fungi, bacteria, actinomycetes, plants, and pathogenic fungi. It was shown that the ecological plasticity of the Trichoderma genus in the soil of this zone is determined by its growth rate, the optimum pH and temperature, the biosynthesis of extracellular hydrolytic enzymes, the biological action of mycotoxins, and the ability for parasitism. The efficiency of the introduction of Trichoderma species typical and atypical for the leached chernozem into this soil and their influence on the structure of the microbial community were evaluated. The T. pseudokoningii ecotype, which produces cellulolytic enzymes, is very promising for industrial biotechnology, and the T. harzianum ecotype can be used in soil biotechnology for the biocontrol of chernozem. The addition of a commercial trichodermin preparation into the chernozem damages the structure of its microbial community.

Genome Sequencing and Comparative Transcriptomics of the Model Entomopathogenic Fungi Metarhizium anisopliae and M. acridum

Science.gov (United States)

Shang, Yanfang; Duan, Zhibing; Hu, Xiao; Xie, Xue-Qin; Zhou, Gang; Peng, Guoxiong; Luo, Zhibing; Huang, Wei; Wang, Bing; Fang, Weiguo; Wang, Sibao; Zhong, Yi; Ma, Li-Jun; St. Leger, Raymond J.; Zhao, Guo-Ping; Pei, Yan; Feng, Ming-Guang; Xia, Yuxian; Wang, Chengshu

2011-01-01

Metarhizium spp. are being used as environmentally friendly alternatives to chemical insecticides, as model systems for studying insect-fungus interactions, and as a resource of genes for biotechnology. We present a comparative analysis of the genome sequences of the broad-spectrum insect pathogen Metarhizium anisopliae and the acridid-specific M. acridum. Whole-genome analyses indicate that the genome structures of these two species are highly syntenic and suggest that the genus Metarhizium evolved from plant endophytes or pathogens. Both M. anisopliae and M. acridum have a strikingly larger proportion of genes encoding secreted proteins than other fungi, while ∼30% of these have no functionally characterized homologs, suggesting hitherto unsuspected interactions between fungal pathogens and insects. The analysis of transposase genes provided evidence of repeat-induced point mutations occurring in M. acridum but not in M. anisopliae. With the help of pathogen-host interaction gene database, ∼16% of Metarhizium genes were identified that are similar to experimentally verified genes involved in pathogenicity in other fungi, particularly plant pathogens. However, relative to M. acridum, M. anisopliae has evolved with many expanded gene families of proteases, chitinases, cytochrome P450s, polyketide synthases, and nonribosomal peptide synthetases for cuticle-degradation, detoxification, and toxin biosynthesis that may facilitate its ability to adapt to heterogenous environments. Transcriptional analysis of both fungi during early infection processes provided further insights into the genes and pathways involved in infectivity and specificity. Of particular note, M. acridum transcribed distinct G-protein coupled receptors on cuticles from locusts (the natural hosts) and cockroaches, whereas M. anisopliae transcribed the same receptor on both hosts. This study will facilitate the identification of virulence genes and the development of improved biocontrol strains

Not in your usual Top 10: protists that infect plants and algae.

Science.gov (United States)

Schwelm, Arne; Badstöber, Julia; Bulman, Simon; Desoignies, Nicolas; Etemadi, Mohammad; Falloon, Richard E; Gachon, Claire M M; Legreve, Anne; Lukeš, Julius; Merz, Ueli; Nenarokova, Anna; Strittmatter, Martina; Sullivan, Brooke K; Neuhauser, Sigrid

2018-04-01

Fungi, nematodes and oomycetes belong to the most prominent eukaryotic plant pathogenic organisms. Unicellular organisms from other eukaryotic lineages, commonly addressed as protists, also infect plants. This review provides an introduction to plant pathogenic protists, including algae infecting oomycetes, and their current state of research. © 2017 THE AUTHORS. MOLECULAR PLANT PATHOLOGY PUBLISHED BY BRITISH SOCIETY FOR PLANT PATHOLOGY AND JOHN WILEY & SONS LTD.

Fungicidal seed coatings exert minor effects on arbuscular mycorrhizal fungi and plant nutrient content

Science.gov (United States)

Aims: Determine if contemporary, seed-applied fungicidal formulations inhibit colonization of plant roots by arbuscular mycorrhizal (AM) fungi, plant development, or plant nutrient content during early vegetative stages of several commodity crops. Methods: We evaluated seed-applied commercial fungic...

Massive gene swamping among cheese-making Penicillium fungi

Directory of Open Access Journals (Sweden)

Jeanne Ropars

2015-03-01

Full Text Available Horizontal gene transfers (HGT, i.e., the transmission of genetic material between species not directly attributable to meiotic gene exchange, have long been acknowledged as a major driver of prokaryotic evolution and is increasingly recognized as an important source of adaptation in eukaryotes. In fungi in particular, many convincing examples of HGT have been reported to confer selective advantages on the recipient fungal host, either promoting fungal pathogenicity on plants or increasing their toxicity by the acquisition of secondary metabolic clusters, resulting in adaptation to new niches and in some cases eventually even in speciation. These horizontal gene transfers involve single genes, complete metabolic pathways or even entire chromosomes. A recent study has uncovered multiple recent horizontal transfers of a 575 kb genomic island in cheese Penicillium fungi, representing ca. 2% of the Penicillium roqueforti’s genome, that may confer selective advantage in the competing cheese environment where bacteria and fungi occur. Novel phylogenomic methods are being developed, revealing massive HGT among fungi. Altogether, these recent studies indicate that HGT is a crucial mechanism of rapid adaptation, even among eukaryotes.

Exploiting amoeboid and non-vertebrate animal model systems to study the virulence of human pathogenic fungi.

Science.gov (United States)

Mylonakis, Eleftherios; Casadevall, Arturo; Ausubel, Frederick M

2007-07-27

Experiments with insects, protozoa, nematodes, and slime molds have recently come to the forefront in the study of host-fungal interactions. Many of the virulence factors required for pathogenicity in mammals are also important for fungal survival during interactions with non-vertebrate hosts, suggesting that fungal virulence may have evolved, and been maintained, as a countermeasure to environmental predation by amoebae and nematodes and other small non-vertebrates that feed on microorganisms. Host innate immune responses are also broadly conserved across many phyla. The study of the interaction between invertebrate model hosts and pathogenic fungi therefore provides insights into the mechanisms underlying pathogen virulence and host immunity, and complements the use of mammalian models by enabling whole-animal high throughput infection assays. This review aims to assist researchers in identifying appropriate invertebrate systems for the study of particular aspects of fungal pathogenesis.

Patogenic fungi associated with blue lupine seeds

Directory of Open Access Journals (Sweden)

Bogdan Nowicki

2013-12-01

Full Text Available Over 10% ofseeds harvested in 1991 and 1992 (50 samples, 400 seeds in each sample proved to be infested with various fungi. Fusarium spp. and Botrytis cinerea were the most common pathogens isolated. Fusarium avenaceum was the most common and highIy pathogenic species. Fusarium semitectum and F. tricinctum were highly pathogenic to lupin seedlings but they were the least common Fusarium isolated from seeds. Similarily, Sclerotinia sclerotiorum was isolated only from 0,2% seeds tested but this fungus was highly pathogenic to lupin seedlings. Some other fungi know as lupin pathogens (F. oxysporum, Stemphylium botryosum, Pleiochaeta setosa and Phomopsis leptostromiformis were also noted in tested seeds.

The effect of chitosan on limitation of growth and development of some pathogenic fungi for ornamental plants

Directory of Open Access Journals (Sweden)

Alicja Saniewska

2013-12-01

Full Text Available The inhibitory effect of crab-shell chitosan, medium (200-800 cps and high molecular weight ( 800-2000 cps (purchased from Sigma-Aldrich Chemicals toward Alternaria alternata, Botrytis tulipae, Fiisarium oxysporum f. sp. callistephi, Fusarium oxysporum f. sp. tulipae, Phoma narcissi and Phoma poolensis was evaluated in vitro and in vivo. The chitosan evidently inhibited in vitro growth of all tested pathogens, with a marked effect at higher concentrations above 200 μg/cm3. Chitosan at a concentration of 1,25; 2,5 and 5,0 mg/cm3 didn't have inhibitory action in appearance of fungi growth on naturally contaminated Callistephus chinensis seeds. At the same concentrations, chitosan applied as bulb scales dressing of Hymenocallis narcissiflora bulbs, before inoculation or after inoculation with Phoma narcissi, inhibited the development of necrotic spots on scales. Chitosan used preventively or curatively at a concentrations of 1,25; 2,5 and 5,0 mg/cm3 indicated inhibitory effect on development of Fusarium oxysporum f. sp. tulipae on tulip bulbs. Chitosan at a concentration of 10 mg/cm3 applied preventively (first spray 12th June was very effective in the control of Puccinia antirrhini on snapdragon in the field. The strongest inhibitory effect was observed on snapdragon treated 8 times at week intervals.

Diverse Lifestyles and Strategies of Plant Pathogenesis Encoded in the Genomes of Eighteen Dothideomycetes Fungi

Energy Technology Data Exchange (ETDEWEB)

Ohm, Robin A.; Feau, Nicolas; Henrissat, Bernard; Schoch, Conrad L.; Horwitz, Benjamin A.; Barry, Kerrie W.; Condon, Bradford J.; Copeland, Alex C.; Dhillon, Braham; Glaser, Fabian; Hesse, Cedar N.; Kosti, Idit; LaButti, Kurt; Lindquist, Erika A.; Lucas, Susan; Salamov, Asaf A.; Bradshaw, Rosie E.; Ciuffetti, Lynda; Hamelin, Richard C.; Kema, Gert H. J.; Lawrence, Christopher; Scott, James A.; Spatafora, Joseph W.; Turgeon, B. Gillian; Wit, Pierre J. G. M. de; Zhong, Shaobin; Goodwin, Stephen B.; Grigoriev, Igor V.

2012-02-29

The class Dothideomycetes is one of the largest groups of fungi with a high level of ecological diversity including many plant pathogens infecting a broad range of hosts. Here, we compare genome features of 18 members of this class, including 6 necrotrophs, 9 (hemi)biotrophs and 3 saprotrophs, to analyze genome structure, evolution, and the diverse strategies of pathogenesis. The Dothideomycetes most likely evolved from a common ancestor more than 280 million years ago. The 18 genome sequences differ dramatically in size due to variation in repetitive content, but show much less variation in number of (core) genes. Gene order appears to have been rearranged mostly within chromosomal boundaries by multiple inversions, in extant genomes frequently demarcated by adjacent simple repeats. Several Dothideomycetes contain one or more gene-poor, transposable element (TE)-rich putatively dispensable chromosomes of unknown function. The 18 Dothideomycetes offer an extensive catalogue of genes involved in cellulose degradation, proteolysis, secondary metabolism, and cysteine-rich small secreted proteins. Ancestors of the two major orders of plant pathogens in the Dothideomycetes, the Capnodiales and Pleosporales, may have had different modes of pathogenesis, with the former having fewer of these genes than the latter. Many of these genes are enriched in proximity to transposable elements, suggesting faster evolution because of the effects of repeat induced point (RIP) mutations. A syntenic block of genes, including oxidoreductases, is conserved in most Dothideomycetes and upregulated during infection in L. maculans, suggesting a possible function in response to oxidative stress.

Botryosphaeria dothidea: a latent pathogen of global importance to woody plant health

NARCIS (Netherlands)

Marsberg, Angelica; Kemler, Martin; Jami, Fahimeh; Nagel, Jan H.; Postma-Smidt, Alisa; Naidoo, Sanushka; Wingfield, Michael J.; Crous, Pedro W.; Spatafora, Joseph W.; Hesse, Cedar N.; Robbertse, Barbara; Slippers, Bernard

Botryosphaeria dothidea is the type species of Botryosphaeria (Botryosphaeriaceae, Botryosphaeriales). Fungi residing in this order are amongst the most widespread and important canker and dieback pathogens of trees worldwide, with B. dothidea one of the most common species on a large number of

Isolation and Identification of Pathogenic Fungi from Thorns and Thistles in Isfahan and Adjacent Cities

Directory of Open Access Journals (Sweden)

M Emami

2007-12-01

Full Text Available Introduction: The most important subcutaneous fungal infections in man are caused by injury due to contaminated thistles and thorns. From an epidemiological point of view , it is important to recognize the fungi as well as their frequency of them in various thistles and thorns Methods: The present research has been conducted on thorns and thistles of 16 regions including cities and villages of Isfahan province. 800 samples have been collected. Specimens were inoculated and incubated at 25◦C in S & SCC medium. In order to isolate and identify the fungi, cultures in specific media, intraperitoneal injections of mice and disc diffusion test have been applied. Results: Over one year of study, 1676 colonies of actinomycetes and fungi were recognized. The most common fungi were as follows: Alternaria (22/4%,Aspergillus(11/8% , Cladosporium (10/8%,Esteril mycellium(10/6% and Penicillium (9/7%. The prevalence was most in Shahreza city(10/2% , while the least was in Ardestan(3%. The most prevalent yeasts were Candida tropicalis (50% , Rodotrula rubra (12/5% , Candida kerusei(11/4%,Trichosporon candida (7/9% , Unknown yeasts (6/8%, Candida gillermondi (5/7%, Saccharomyces cervisia (3/4%, Geotricum candidum and Trichosporon glabrata (Candida glabrata each one (1/1%. The prevalence was most in Khansar city(19/2%. In this study, 4 species similar to Coccidioides immitis, Phialophora verrucosa (4 species and Exophiala jeanselmei (3 species were identified. Conclusion: In this study done for the first time in this area, pathogenic and opportunistic fungi were isolated. Furthermore, Exophiala jeanselmei and Nocardiopsis dassonvillei were isolated for the first time from thorns in the country.

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.

The genetic basis of local adaptation for pathogenic fungi in agricultural ecosystems.

Science.gov (United States)

Croll, Daniel; McDonald, Bruce A

2017-04-01

Local adaptation plays a key role in the evolutionary trajectory of host-pathogen interactions. However, the genetic architecture of local adaptation in host-pathogen systems is poorly understood. Fungal plant pathogens in agricultural ecosystems provide highly tractable models to quantify phenotypes and map traits to corresponding genomic loci. The outcome of crop-pathogen interactions is thought to be governed largely by gene-for-gene interactions. However, recent studies showed that virulence can be governed by quantitative trait loci and that many abiotic factors contribute to the outcome of the interaction. After introducing concepts of local adaptation and presenting examples from wild plant pathosystems, we focus this review on a major pathogen of wheat, Zymoseptoria tritici, to show how a multitude of traits can affect local adaptation. Zymoseptoria tritici adapted to different thermal environments across its distribution range, indicating that thermal adaptation may limit effective dispersal to different climates. The application of fungicides led to the rapid evolution of multiple, independent resistant populations. The degree of colony melanization showed strong pleiotropic effects with other traits, including trade-offs with colony growth rates and fungicide sensitivity. The success of the pathogen on its host can be assessed quantitatively by counting pathogen reproductive structures and measuring host damage based on necrotic lesions. Interestingly, these two traits can be weakly correlated and depend both on host and pathogen genotypes. Quantitative trait mapping studies showed that the genetic architecture of locally adapted traits varies from single loci with large effects to many loci with small individual effects. We discuss how local adaptation could hinder or accelerate the development of epidemics in agricultural ecosystems. © 2016 John Wiley & Sons Ltd.

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.

Genetics-based interactions among plants, pathogens, and herbivores define arthropod community structure.

Science.gov (United States)

Busby, Posy E; Lamit, Louis J; Keith, Arthur R; Newcombe, George; Gehring, Catherine A; Whitham, Thomas G; Dirzo, Rodolfo

2015-07-01

Plant resistance to pathogens or insect herbivores is common, but its potential for indirectly influencing plant-associated communities is poorly known. Here, we test whether pathogens' indirect effects on arthropod communities and herbivory depend on plant resistance to pathogens and/or herbivores, and address the overarching interacting foundation species hypothesis that genetics-based interactions among a few highly interactive species can structure a much larger community. In a manipulative field experiment using replicated genotypes of two Populus species and their interspecific hybrids, we found that genetic variation in plant resistance to both pathogens and insect herbivores modulated the strength of pathogens' indirect effects on arthropod communities and insect herbivory. First, due in part to the pathogens' differential impacts on leaf biomass among the two Populus species and the hybrids, the pathogen most strongly impacted arthropod community composition, richness, and abundance on the pathogen-susceptible tree species. Second, we found similar patterns comparing pathogen-susceptible and pathogen-resistant genotypes within species. Third, within a plant species, pathogens caused a fivefold greater reduction in herbivory on insect-herbivore-susceptible plant genotypes than on herbivore-resistant genotypes, demonstrating that the pathogen-herbivore interaction is genotype dependent. We conclude that interactions among plants, pathogens, and herbivores can structure multitrophic communities, supporting the interacting foundation species hypothesis. Because these interactions are genetically based, evolutionary changes in genetic resistance could result in ecological changes in associated communities, which may in turn feed back to affect plant fitness.

Impact of selected antagonistic fungi on Fusarium species – toxigenic cereal pathogens

Directory of Open Access Journals (Sweden)

Delfina Popiel

2013-12-01

Full Text Available Fusarium-ear blight is a destructive disease in various cereal-growing regions and leads to significant yield and quality losses for farmers and to contamination of cereal grains with mycotoxins, mainly deoxynivalenol and derivatives, zearalenone and moniliformin. Fusarium pathogens grow well and produce significant inoculum on crop resiudues. Reduction of mycotoxins production and pathogen sporulation may be influenced by saprophytic fungi, exhibiting antagonistic effect. Dual culture bioassays were used to examine the impact of 92 isolates (belonging to 29 fungal species against three toxigenic species, i.e. Fusarium avenaceum (Corda Saccardo, F. culmorum (W.G.Smith Saccardo and F. graminearum Schwabe. Both F.culmorum and F. graminearum isolates produce trichothecene mycotoxins and mycohormone zearalenone and are considered to be the most important cereal pathogens worldwide. Infection with those pathogens leads to accumulation of mycotoxins: deoxynivalenol (DON and zearalenone (ZEA in grains. Fusarium avenaceum isolates are producers of moniliformin (MON and enniatins. Isolates of Trichoderma sp. were found to be the most effective ones to control the growth of examined Fusarium species. The response of Fusarium isolates to antagonistic activity of Trichoderma isolates varied and also the isolates of Trichoderma differed in their antagonistic activity against Fusarium isolates. The production of MON by two isolates of F. avenaceum in dual culture on rice was reduced by 95% to 100% by T. atroviride isolate AN 35. The same antagonist reduced the amount of moniliformin from 100 μg/g to 6.5 μg/g when inoculated to rice culture contaminated with MON, which suggests the possible decomposition of this mycotoxin.

Nonhost resistance to rust pathogens – a continuation of continua

Science.gov (United States)

Bettgenhaeuser, Jan; Gilbert, Brian; Ayliffe, Michael; Moscou, Matthew J.

2014-01-01

The rust fungi (order: Pucciniales) are a group of widely distributed fungal plant pathogens, which can infect representatives of all vascular plant groups. Rust diseases significantly impact several crop species and considerable research focuses on understanding the basis of host specificity and nonhost resistance. Like many pathogens, rust fungi vary considerably in the number of hosts they can infect, such as wheat leaf rust (Puccinia triticina), which can only infect species in the genera Triticum and Aegilops, whereas Asian soybean rust (Phakopsora pachyrhizi) is known to infect over 95 species from over 42 genera. A greater understanding of the genetic basis determining host range has the potential to identify sources of durable resistance for agronomically important crops. Delimiting the boundary between host and nonhost has been complicated by the quantitative nature of phenotypes in the transition between these two states. Plant–pathogen interactions in this intermediate state are characterized either by (1) the majority of accessions of a species being resistant to the rust or (2) the rust only being able to partially complete key components of its life cycle. This leads to a continuum of disease phenotypes in the interaction with different plant species, observed as a range from compatibility (host) to complete immunity within a species (nonhost). In this review we will highlight how the quantitative nature of disease resistance in these intermediate interactions is caused by a continuum of defense barriers, which a pathogen needs to overcome for successfully establishing itself in the host. To illustrate continua as this underlying principle, we will discuss the advances that have been made in studying nonhost resistance towards rust pathogens, particularly cereal rust pathogens. PMID:25566270

Influence of mycorrhizal fungi on survival of salmonella and E.coli O157:H7 in soil and translocation into allium porrum roots and stem

Science.gov (United States)

Modern agriculture disrupts the natural symbiotic relationship arbuscular mycorrhizal (AM) fungi have with most vegetable plants, which may affect translocation of human pathogens into the plant. Five-month-old Allium porrum (leek) plants (with or without AMF [Glomus intraradices]) were used as a m...

Contribution of soil-32P, fertilizer-32P and VA mycorrhizal fungi to phosphorus nutrition of corn plant

International Nuclear Information System (INIS)

Feng Gu; Yang Maoqiu; Bai Dengsha; Huang Quansheng

1997-01-01

32 P labelled fertilizer and five synthetic phosphates (dicalcium phosphate, octocalcium phosphate, iron phosphate, aluminium phosphate and apatite), which were used to simulate inorganic phosphates such as Ca 2 -P, Ca 8 -P, Fe P , Al-P and Ca 10 -P in calcareous soil, were applied to corn plants inoculating with and without vesicular-arbuscular (VA) mycorrhizal fungi in a calcareous soil. The results showed that VA mycorrhizal fungi and dicalcium phosphate, octocalcium phosphate, iron phosphate, aluminium phosphate promoted growth and increased phosphorus content of corn plant. The four synthetic phosphates except apatite had higher contributions to corn plant growth than VA mycorrhizal fungi. Contributions of fertilizer-P, soil-P and synthetic phosphates to phosphorus nutrition of corn plant were in order of synthetic phosphates (except apatite) > soil- P > fertilizer-P. Inoculating with VA mycorrhizal fungi increased the contribution of soil-P and decreased the contribution of synthetic phosphates, but did not affect the contribution of fertilizer-P

Plant Responses to Pathogen Attack: Small RNAs in Focus.

Science.gov (United States)

Islam, Waqar; Noman, Ali; Qasim, Muhammad; Wang, Liande

2018-02-08

Small RNAs (sRNA) are a significant group of gene expression regulators for multiple biological processes in eukaryotes. In plants, many sRNA silencing pathways produce extensive array of sRNAs with specialized roles. The evidence on record advocates for the functions of sRNAs during plant microbe interactions. Host sRNAs are reckoned as mandatory elements of plant defense. sRNAs involved in plant defense processes via different pathways include both short interfering RNA (siRNA) and microRNA (miRNA) that actively regulate immunity in response to pathogenic attack via tackling pathogen-associated molecular patterns (PAMPs) and other effectors. In response to pathogen attack, plants protect themselves with the help of sRNA-dependent immune systems. That sRNA-mediated plant defense responses play a role during infections is an established fact. However, the regulations of several sRNAs still need extensive research. In this review, we discussed the topical advancements and findings relevant to pathogen attack and plant defense mediated by sRNAs. We attempted to point out diverse sRNAs as key defenders in plant systems. It is hoped that sRNAs would be exploited as a mainstream player to achieve food security by tackling different plant diseases.

Exploiting amoeboid and non-vertebrate animal model systems to study the virulence of human pathogenic fungi.

Directory of Open Access Journals (Sweden)

Eleftherios Mylonakis

2007-07-01

Full Text Available Experiments with insects, protozoa, nematodes, and slime molds have recently come to the forefront in the study of host-fungal interactions. Many of the virulence factors required for pathogenicity in mammals are also important for fungal survival during interactions with non-vertebrate hosts, suggesting that fungal virulence may have evolved, and been maintained, as a countermeasure to environmental predation by amoebae and nematodes and other small non-vertebrates that feed on microorganisms. Host innate immune responses are also broadly conserved across many phyla. The study of the interaction between invertebrate model hosts and pathogenic fungi therefore provides insights into the mechanisms underlying pathogen virulence and host immunity, and complements the use of mammalian models by enabling whole-animal high throughput infection assays. This review aims to assist researchers in identifying appropriate invertebrate systems for the study of particular aspects of fungal pathogenesis.

The Ecological Genomics of Fungi: Repeated Elements in Filamentous Fungi with a Focus on Wood-Decay Fungi

Energy Technology Data Exchange (ETDEWEB)

Murat, Claude [INRA, Nancy, France; Payen, Thibaut [INRA, Nancy, France; Petitpierre, Denis [INRA, Nancy, France; Labbe, Jessy L [ORNL

2013-01-01

In the last decade, the genome of several dozen filamentous fungi have been sequenced. Interestingly, vast diversity in genome size was observed (Fig. 2.1) with 14-fold differences between the 9 Mb of the human pathogenic dandruff fungus (Malassezia globosa; Xu, Saunders, et al., 2007) and the 125 Mb of the ectomycorrhizal black truffle of P rigord (Tuber melanosporum; Martin, Kohler, et al., 2010). Recently, Raffaele and Kamoun (2012) highlighted that the genomes of several lineages of filamentous plant pathogens have been shaped by repeat-driven expansion. Indeed, repeated elements are ubiquitous in all prokaryote and eukaryote genomes; however, their frequencies can vary from just a minor percentage of the genome to more that 60 percent of the genome. Repeated elements can be classified in two major types: satellites DNA and transposable elements. In this chapter, the different types of repeated elements and how these elements can impact genome and gene repertoire will be described. Also, an intriguing link between the transposable elements richness and diversity and the ecological niche will be highlighted.

Biocontrol traits of plant growth suppressive arbuscular mycorrhizal fungi against root rot in tomato caused by Pythium aphanidermatum

DEFF Research Database (Denmark)

Larsen, John; Graham, James H.; Cubero, Jaime

2012-01-01

Arbuscular mycorrhizal (AM) fungi known to cause plant growth depressions in tomato were examined for their biocontrol effects against root rot caused by Pythium aphanidermatum. The main hypothesis was that plant growth suppressive AM fungi would elicit a defence response in the host plant reduci...

Dermatophytes and other pathogenic fungi from hospital staff ...

African Journals Online (AJOL)

hospital staff apparel from protective gown, face- shields and hand gloves were tested for the presence of fungi. Examined samples were collected using the swab culture method. Results: Of a total of 110 swab samples of hospital staff apparel, 56 (51 %) showed fungi contamination including 31 (66 %) of 47 samples from ...

Phytopharmacology of the rice diseases. I. In vitro tests on application of the dust fungicides to the important pathogenic fungi

Energy Technology Data Exchange (ETDEWEB)

Hashioka, Y; Saito, T

1953-01-01

In this paper, the results of experiments on the repressing effect of selected fungicides on the growth of pathogenic fungi of rice are reported. Organic mercury compounds were tested and found to be more effective fungicides than copper. Their use in agriculture is recommended.

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.

Novel Micro-organisms controlling plant pathogens

NARCIS (Netherlands)

Köhl, J.

2009-01-01

The invention relates to control of pathogen caused diseases on leaves, fruits and ears in plants, such as apple scab (Venturia inaequalis by treatment of plant with an isolate of Cladosporium cladosporioides. The treatment is effective in both prevention and treatment of the fungal infection

Novel Micro-organisms controlling plant pathogens

NARCIS (Netherlands)

Köhl, J.

2010-01-01

The invention relates to control of pathogen caused diseases on leaves, fruits and ears in plants, such as apple scab (Venturia inaequalis by treatment of plant with an isolate of Cladosporium cladosporioides. The treatment is effective in both prevention and treatment of the fungal infection

Phylogenomic Analyses Indicate that Early Fungi Evolved Digesting Cell Walls of Algal Ancestors of Land Plants

Science.gov (United States)

Chang, Ying; Wang, Sishuo; Sekimoto, Satoshi; Aerts, Andrea L.; Choi, Cindy; Clum, Alicia; LaButti, Kurt M.; Lindquist, Erika A.; Yee Ngan, Chew; Ohm, Robin A.; Salamov, Asaf A.; Grigoriev, Igor V.; Spatafora, Joseph W.; Berbee, Mary L.

2015-01-01

As decomposers, fungi are key players in recycling plant material in global carbon cycles. We hypothesized that genomes of early diverging fungi may have inherited pectinases from an ancestral species that had been able to extract nutrients from pectin-containing land plants and their algal allies (Streptophytes). We aimed to infer, based on pectinase gene expansions and on the organismal phylogeny, the geological timing of the plant–fungus association. We analyzed 40 fungal genomes, three of which, including Gonapodya prolifera, were sequenced for this study. In the organismal phylogeny from 136 housekeeping loci, Rozella diverged first from all other fungi. Gonapodya prolifera was included among the flagellated, predominantly aquatic fungal species in Chytridiomycota. Sister to Chytridiomycota were the predominantly terrestrial fungi including zygomycota I and zygomycota II, along with the ascomycetes and basidiomycetes that comprise Dikarya. The Gonapodya genome has 27 genes representing five of the seven classes of pectin-specific enzymes known from fungi. Most of these share a common ancestry with pectinases from Dikarya. Indicating functional and sequence similarity, Gonapodya, like many Dikarya, can use pectin as a carbon source for growth in pure culture. Shared pectinases of Dikarya and Gonapodya provide evidence that even ancient aquatic fungi had adapted to extract nutrients from the plants in the green lineage. This implies that 750 million years, the estimated maximum age of origin of the pectin-containing streptophytes represents a maximum age for the divergence of Chytridiomycota from the lineage including Dikarya. PMID:25977457

The hidden duplication past of the plant pathogen Phytophthora and its consequences for infection

Directory of Open Access Journals (Sweden)

Martens Cindy

2010-06-01

Full Text Available Abstract Background Oomycetes of the genus Phytophthora are pathogens that infect a wide range of plant species. For dicot hosts such as tomato, potato and soybean, Phytophthora is even the most important pathogen. Previous analyses of Phytophthora genomes uncovered many genes, large gene families and large genome sizes that can partially be explained by significant repeat expansion patterns. Results Analysis of the complete genomes of three different Phytophthora species, using a newly developed approach, unveiled a large number of small duplicated blocks, mainly consisting of two or three consecutive genes. Further analysis of these duplicated genes and comparison with the known gene and genome duplication history of ten other eukaryotes including parasites, algae, plants, fungi, vertebrates and invertebrates, suggests that the ancestor of P. infestans, P. sojae and P. ramorum most likely underwent a whole genome duplication (WGD. Genes that have survived in duplicate are mainly genes that are known to be preferentially retained following WGDs, but also genes important for pathogenicity and infection of the different hosts seem to have been retained in excess. As a result, the WGD might have contributed to the evolutionary and pathogenic success of Phytophthora. Conclusions The fact that we find many small blocks of duplicated genes indicates that the genomes of Phytophthora species have been heavily rearranged following the WGD. Most likely, the high repeat content in these genomes have played an important role in this rearrangement process. As a consequence, the paucity of retained larger duplicated blocks has greatly complicated previous attempts to detect remnants of a large-scale duplication event in Phytophthora. However, as we show here, our newly developed strategy to identify very small duplicated blocks might be a useful approach to uncover ancient polyploidy events, in particular for heavily rearranged genomes.

Mycological assessment of sediments in Ligurian beaches in the Northwestern Mediterranean: pathogens and opportunistic pathogens.

Science.gov (United States)

Salvo, Vanessa-Sarah; Fabiano, Mauro

2007-05-01

Sediments of five Ligurian beaches in compliance with European Union bathing water regulations were studied based on the characteristics of the fungal assemblage during the tourism season. Among the 179 taxa of filamentous fungi isolated, 120 were opportunistic pathogens, such as Acremonium sp., and the genus Penicillium was also present as the pathogenic species P. citrinum. Furthermore, 5% of the total filamentous fungi belonged to the dermatophyte genus Microsporum, whose species can cause mycoses. Beach sediments showed elevated densities of opportunistic pathogens, of pathogenic filamentous fungi, and of yeasts during the tourism season. Although monitoring of beach sediments for microbiological contamination is not mandatory, and disease transmission from sediments has not yet been demonstrated, our study suggests that beach sediments may act as a reservoir of potential pathogens, including fungi. In addition, the mycoflora displayed high sensitivity to critical environmental situations in the beaches studied. Therefore, the fungal community can be a useful tool for assessing the quality of sandy beaches in terms of sanitary and environmental quality.

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

Full Text Available The regulation of intracellular levels of reactive oxygen species (ROS is critical for developmental differentiation and virulence of many pathogenic fungi. In this report we demonstrate that a novel transmembrane protein, TmpL, is necessary for regulation of intracellular ROS levels and tolerance to external ROS, and is required for infection of plants by the necrotroph Alternaria brassicicola and for infection of mammals by the human pathogen Aspergillus fumigatus. In both fungi, tmpL encodes a predicted hybrid membrane protein containing an AMP-binding domain, six putative transmembrane domains, and an experimentally-validated FAD/NAD(P-binding domain. Localization and gene expression analyses in A. brassicicola indicated that TmpL is associated with the Woronin body, a specialized peroxisome, and strongly expressed during conidiation and initial invasive growth in planta. A. brassicicola and A. fumigatus DeltatmpL strains exhibited abnormal conidiogenesis, accelerated aging, enhanced oxidative burst during conidiation, and hypersensitivity to oxidative stress when compared to wild-type or reconstituted strains. Moreover, A. brassicicola DeltatmpL strains, although capable of initial penetration, exhibited dramatically reduced invasive growth on Brassicas and Arabidopsis. Similarly, an A. fumigatus DeltatmpL mutant was dramatically less virulent than the wild-type and reconstituted strains in a murine model of invasive aspergillosis. Constitutive expression of the A. brassicicola yap1 ortholog in an A. brassicicola DeltatmpL strain resulted in high expression levels of genes associated with oxidative stress tolerance. Overexpression of yap1 in the DeltatmpL background complemented the majority of observed developmental phenotypic changes and partially restored virulence on plants. Yap1-GFP fusion strains utilizing the native yap1 promoter exhibited constitutive nuclear localization in the A. brassicicola DeltatmpL background. Collectively, we

Co-occurrence and hybridization of anther-smut pathogens specialized on Dianthus hosts.

Science.gov (United States)

Petit, Elsa; Silver, Casey; Cornille, Amandine; Gladieux, Pierre; Rosenthal, Lisa; Bruns, Emily; Yee, Sarah; Antonovics, Janis; Giraud, Tatiana; Hood, Michael E

2017-04-01

Host specialization has important consequences for the diversification and ecological interactions of obligate pathogens. The anther-smut disease of natural plant populations, caused by Microbotryum fungi, has been characterized by specialized host-pathogen interactions, which contribute in part to the isolation among these numerous fungal species. This study investigated the molecular variation of Microbotryum pathogens within the geographic and host-specific distributions on wild Dianthus species in southern European Alps. In contrast to prior studies on this pathogen genus, a range of overlapping host specificities was observed for four delineated Microbotryum lineages on Dianthus hosts, and their frequent co-occurrence within single-host populations was quantified at local and regional scales. In addition to potential consequences for direct pathogen competition, the sympatry of Microbotryum lineages led to hybridization between them in many populations, and these admixed genotypes suffered significant meiotic sterility. Therefore, this investigation of the anther-smut fungi reveals how variation in the degrees of host specificity can have major implications for ecological interactions and genetic integrity of differentiated pathogen lineages. © 2017 John Wiley & Sons Ltd.

Analysis of Canadian and Irish forage, oats and commercially available equine concentrate feed for pathogenic fungi and mycotoxins

Directory of Open Access Journals (Sweden)

Buckley Thomas

2007-04-01

Full Text Available Abstract Respiratory infections, recurrent airway obstruction (RAO and exercise induced pulmonary haemorrhage (EIPH are major causes of poor performance in horses. Fungi and mycotoxins are now recognised as a major cause of these conditions. The most notable fungi are Aspergillus and Fusarium. Fungal spores can originate from forage, bedding and feed and, in turn, these fungal spores can produce a series of mycotoxins as secondary metabolites. This study set out to ascertain the degree of fungal and mycotoxin contamination in feed and fodder used in Irish racing yards over a one-year period. Weather conditions in forage producing areas were sampled by Met Eireann and the Canadian Meteorological Service. Fifty per cent of Irish hay, 37% of haylage and 13% of Canadian hay contained pathogenic fungi. Of the mycotoxins, T2 and zearalenone were most prominent. Twenty-one per cent of Irish hay and 16% of pelleted feed contained zearalenone. Forty per cent of oats and 54% of pelleted feed contained T2 toxins.

Analysis of Canadian and Irish forage, oats and commercially available equine concentrate feed for pathogenic fungi and mycotoxins.

Science.gov (United States)

Buckley, Thomas; Creighton, Alan; Fogarty, Ursula

2007-04-01

Respiratory infections, recurrent airway obstruction (RAO) and exercise induced pulmonary haemorrhage (EIPH) are major causes of poor performance in horses. Fungi and mycotoxins are now recognised as a major cause of these conditions. The most notable fungi are Aspergillus and Fusarium. Fungal spores can originate from forage, bedding and feed and, in turn, these fungal spores can produce a series of mycotoxins as secondary metabolites.This study set out to ascertain the degree of fungal and mycotoxin contamination in feed and fodder used in Irish racing yards over a one-year period. Weather conditions in forage producing areas were sampled by Met Eireann and the Canadian Meteorological Service.Fifty per cent of Irish hay, 37% of haylage and 13% of Canadian hay contained pathogenic fungi. Of the mycotoxins, T2 and zearalenone were most prominent. Twenty-one per cent of Irish hay and 16% of pelleted feed contained zearalenone. Forty per cent of oats and 54% of pelleted feed contained T2 toxins.

Introduction of Non-Native Pollinators Can Lead to Trans-Continental Movement of Bee-Associated Fungi.

Directory of Open Access Journals (Sweden)

Shannon M Hedtke

Full Text Available Bees are essential pollinators for many flowering plants, including agriculturally important crops such as apple. As geographic ranges of bees or their host plants change as a result of human activities, we need to identify pathogens that could be transmitted among newly sympatric species to evaluate and anticipate their effects on bee communities. We used PCR screening and DNA sequencing to evaluate exposure to potentially disease-causing microorganisms in a pollinator of apple, the horned mason bee (Osmia cornifrons. We did not detect microsporidia, Wolbachia, or trypanosomes, which are common pathogens of bees, in any of the hundreds of mason bees screened. We did detect both pathogenic and apathogenic (saprophytic fungal species in the genus Ascosphaera (chalkbrood, an unidentified species of Aspergillus fungus, and a strain of bacteria in the genus Paenibacillus that is probably apathogenic. We detected pathogenic fungal strains in asymptomatic adult bees that therefore may be carriers of disease. We demonstrate that fungi from the genus Ascosphaera have been transported to North America along with the bee from its native range in Japan, and that O. cornifrons is exposed to fungi previously only identified from nests of other related bee species. Further study will be required to quantify pathogenicity and health effects of these different microbial species on O. cornifrons and on closely-related native North American mason bees that may now be exposed to novel pathogens. A global perspective is required for pathogen research as geographic ranges of insects and microorganisms shift due to intentional or accidental introductions.

Introduction of Non-Native Pollinators Can Lead to Trans-Continental Movement of Bee-Associated Fungi.

Science.gov (United States)

Hedtke, Shannon M; Blitzer, Eleanor J; Montgomery, Graham A; Danforth, Bryan N

2015-01-01

Bees are essential pollinators for many flowering plants, including agriculturally important crops such as apple. As geographic ranges of bees or their host plants change as a result of human activities, we need to identify pathogens that could be transmitted among newly sympatric species to evaluate and anticipate their effects on bee communities. We used PCR screening and DNA sequencing to evaluate exposure to potentially disease-causing microorganisms in a pollinator of apple, the horned mason bee (Osmia cornifrons). We did not detect microsporidia, Wolbachia, or trypanosomes, which are common pathogens of bees, in any of the hundreds of mason bees screened. We did detect both pathogenic and apathogenic (saprophytic) fungal species in the genus Ascosphaera (chalkbrood), an unidentified species of Aspergillus fungus, and a strain of bacteria in the genus Paenibacillus that is probably apathogenic. We detected pathogenic fungal strains in asymptomatic adult bees that therefore may be carriers of disease. We demonstrate that fungi from the genus Ascosphaera have been transported to North America along with the bee from its native range in Japan, and that O. cornifrons is exposed to fungi previously only identified from nests of other related bee species. Further study will be required to quantify pathogenicity and health effects of these different microbial species on O. cornifrons and on closely-related native North American mason bees that may now be exposed to novel pathogens. A global perspective is required for pathogen research as geographic ranges of insects and microorganisms shift due to intentional or accidental introductions.

Diversity of leaf endophytic fungi in mangrove plants of northeast Brazil.

Science.gov (United States)

Wanderley Costa, Isabella P M; Maia, Leonor Costa; Cavalcanti, Maria Auxiliadora

2012-07-01

With the aim of increasing the knowledge about endophytic fungi, a group of microorganisms with high biotechnological potential and a valuable source of useful metabolites, a survey in leaves of mangrove plants (Avicennia schaueriana, Laguncularia racemosa, and Rhizophora mangle) was performed at the Itamaracá Island, PE, Brazil. Leaves were collected, during two seasons, dry and rainy, superficially sterilized and fragments maintained in Petri dishes with Potato dextrose agar (PDA) at 28(o) ± 2(o) C until isolation of the fungi. Fourty taxa were isolated: 25 species representing 19 genera and 15 morphotypes determined as Mycelia sterilia. Leaves of L. racemosa hosted the highest number of colony forming units (CFU) and taxa. Guignardia sp. and Colletotrichum gloeosporioides were the most frequently isolated, while Glomerella cingulata was the only species found in association with the three host plants. The proportional importance of each fungus differed among hosts. The similarity of fungi species between the two seasons reached only 4.2%, and that between the hosts was also low, with the maximum (A. schaueriana x L. racemosa) reaching 24.2%. Sphaerosporium, as well as Chloridium virescens var. virescens, Microsphaeropsis arundinis, Penicillium pinophilum, Periconia cambrensis, Phoma herbarum, P. diachenii, P. obscurans, Sordaria prolifica and Torula elisii are reported for the first time as endophytic in tropical regions.

Phosphorylation and proteome dynamics in pathogen-resistant tomato plants

NARCIS (Netherlands)

Stulemeijer, I.J.E.

2008-01-01

Microbial plant pathogens impose a continuous threat on global food production. Similar to disease resistance in mammals, an innate immune system allows plants to recognise pathogens and swiftly activate defence. For the work described in this thesis, the interaction between tomato and the

Growth responses of maritime sand dune plant species to arbuscular mycorrhizal fungi

Directory of Open Access Journals (Sweden)

Mariusz Tadych

2014-08-01

Full Text Available In a pot experiment conducted in a greenhouse, the response of 6 plant species dominating in the succession of vegetation of a deflation hollow of the Łeba Bar to inoculation with arbuscular mycorrhizal fungi (AMF was investigated. The inoculum was a mixture of soil, roots and spores of 5 species of AMF with the dominant species Glomus aggregatum. Except for Corynephorus canescens and Festuca rubra subsp. arenaria, both the growth and the dry matter of above-ground parts of plants of Agrostis stolonifera, Ammophila arenaria, Corynephorus canescens, Juncus articulatus and J. balticus inoculated with AMF were higher than those growing in soils lacking infection propagules of these fungi. Inoculation with AMF decreased the dry matter of root: shoot ratios in 5 plant species. This property was not determined in Festuca rubra subsp. arenaria due to the death of all control plants. The level of mycorrhizal infection was low and did not correlate with the growth responses found. The high growth reaction of Juncus spp. to AMF found in this study suggests that the opinion of non-mycotrophy or low dependence of plants of Juncaceae on AMF was based on results of investigations of plants growing in wet sites known to inhibit the formation of mycorrhizae.

Plant defenses against parasitic plants show similarities to those induced by herbivores and pathogens

Science.gov (United States)

Justin B. Runyon; Mark C. Mescher; Consuelo M. De Moraes

2010-01-01

Herbivores and pathogens come quickly to mind when one thinks of the biotic challenges faced by plants. Important but less appreciated enemies are parasitic plants, which can have important consequences for the fitness and survival of their hosts. Our knowledge of plant perception, signaling and response to herbivores and pathogens has expanded rapidly in recent years...

[Evaluation of Fusarium spp. pathogenicity in plant and murine models].

Science.gov (United States)

Forero-Reyes, Consuelo M; Alvarado-Fernández, Angela M; Ceballos-Rojas, Ana M; González-Carmona, Lady C; Linares-Linares, Melva Y; Castañeda-Salazar, Rubiela; Pulido-Villamarín, Adriana; Góngora-Medina, Manuel E; Cortés-Vecino, Jesús A; Rodríguez-Bocanegra, María X

The genus Fusarium is widely recognized for its phytopathogenic capacity. However, it has been reported as an opportunistic pathogen in immunocompetent and immunocompromised patients. Thus, it can be considered a microorganism of interest in pathogenicity studies on different hosts. Therefore, this work evaluated the pathogenicity of Fusarium spp. isolates from different origins in plants and animals (murine hosts). Twelve isolates of Fusarium spp. from plants, animal superficial mycoses, and human superficial and systemic mycoses were inoculated in tomato, passion fruit and carnation plants, and in immunocompetent and immunosuppressed BALB/c mice. Pathogenicity tests in plants did not show all the symptoms associated with vascular wilt in the three plant models; however, colonization and necrosis of the vascular bundles, regardless of the species and origin of the isolates, showed the infective potential of Fusarium spp. in different plant species. Moreover, the pathogenicity tests in the murine model revealed behavioral changes. It was noteworthy that only five isolates (different origin and species) caused mortality. Additionally, it was observed that all isolates infected and colonized different organs, regardless of the species and origin of the isolates or host immune status. In contrast, the superficial inoculation test showed no evidence of epidermal injury or colonization. The observed results in plant and murine models suggest the pathogenic potential of Fusarium spp. isolates in different types of hosts. However, further studies on pathogenicity are needed to confirm the multihost capacity of this genus. Copyright © 2017 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

Antifungal activity of saponins originated from Medicago hybrida against some ornamental plant pathogens

Directory of Open Access Journals (Sweden)

Alicja Saniewska

2012-12-01

Full Text Available Antifungal activity of total saponins originated from roots of Medicago hybrida (Pourret Trautv. were evaluated in vitro against six pathogenic fungi and eight individual major saponin glycosides were tested against one of the most susceptible fungi. The total saponins showed fungitoxic effect at all investigated concentrations (0.01%, 0.05% and 0.1% but their potency was different for individual fungi. The highest saponin concentration (0.1% was the most effective and the inhibition of Fusarium oxysporum f. sp. callistephi, Botrytis cinerea, Botrytis tulipae, Phoma narcissi, Fusarium oxysporum f. sp. narcissi was 84.4%, 69.9%, 68.6%, 57.2%, 55.0%, respectively. While Fusarium oxysporum Schlecht., a pathogen of Muscari armeniacum, was inhibited by 9.5% only. Eight major saponin glycosides isolated from the total saponins of M. hybrida roots were tested against the mycelium growth of Botrytis tulipae. The mycelium growth of the pathogen was greatly inhibited by hederagenin 3-O-β-D-glucopyranoside and medicagenic acid 3-O-β-D-glucopyranoside. Medicagenic acid 3-O-β-D-glucuronopyranosyl-28-O-β-D-glucopyranoside and oleanolic acid 3-O-[β-D-glucuronopyranosyl(1→2-α-L-galactopyranosyl]-28-O-β-D-glucopyranoside showed low fungitoxic activity. Medicagenic acid 3-O-a-D-glucopyranosyl- 28-O-β-D-glucopyranoside, hederagenin 3-O-[α-L- hamnopyranosyl(1→2-β-D-glucopyranosyl(1→2-β-D-glucopyranosyl]- 28-O-α-D-glucopyranoside and hederagenin 3-O-β-D-glucuronopyranosyl-28-O-β-D- lucopyranoside did not limit or only slightly inhibited growth of the tested pathogen. While 2β, 3β-dihydroxyolean-12 ene-23-al-28-oic acid 3-O-β-D-glucuronopyranosyl-28-O-β-D-glucopyranoside slightly stimulated mycelium growth of B. tulipae.

Levels of rhizome endophytic fungi fluctuate in Paris polyphylla var. yunnanensis as plants age

Directory of Open Access Journals (Sweden)

Tao Liu

2017-02-01

Full Text Available Paris polyphylla var. yunnanensis is an important medicinal plant with abundant saponins that are widely used in the pharmaceuticals industry. It is unclear why the levels of active ingredients increase as these plants age. We speculated that the concentrations of those components in the rhizomes are mediated by fungal endophytes. To test this hypothesis, we took both culture-dependent and -independent (metagenomics approaches to analyze the communities of endophytic fungi that inhabit those rhizomes in plants of different age classes (four, six, and eight years old. In all, 147 isolates representing 18 fungal taxa were obtained from 270 segments (90 per age class. Based on morphological and genetic characteristics, Fusarium oxysporum (46.55% frequency of occurrence was the predominant endophyte, followed by Leptodontidium sp. (8.66% and Trichoderma viride (6.81%. Colonization of endophytic fungi was maximized in the eight-year-old rhizomes (33.33% when compared with four-year-old (21.21% and six-year-old (15.15% rhizomes. Certain fungal species were present only at particular ages. For example, Alternaria sp., Cylindrocarpon sp., Chaetomium sp., Paraphaeosphaeria sporulosa, Pyrenochaeta sp., Penicillium swiecickii, T. viride, and Truncatella angustata were found only in the oldest plants. Analysis of (metagenomics community DNA extracted from different-aged samples revealed that, at the class level, the majority of fungi had the highest sequence similarity to members of Sordariomycetes, followed by Eurotiomycetes and Saccharomycetes. These results were mostly in accord with those we obtained using culture methods. Fungal diversity and richness also changed over time. Our investigation is the first to show that the diversity of fungi in rhizomes of P. polyphylla var. yunnanensis is altered as plants age, and our findings provide a foundation for future examinations of useful compounds.

Underground friends or enemies: model plants help to unravel direct and indirect effects of arbuscular mycorrhizal fungi on plant competition.

Science.gov (United States)

Facelli, Evelina; Smith, Sally E; Facelli, José M; Christophersen, Helle M; Andrew Smith, F

2010-03-01

*We studied the effects of two arbuscular mycorrhizal (AM) fungi, singly or together, on the outcome of competition between a host (tomato cultivar, wild-type (WT)) and a surrogate nonhost (rmc, a mycorrhiza-defective mutant of WT) as influenced by the contributions of the direct and AM phosphorus (P) uptake pathways to plant P. *We grew plants singly or in pairs of the same or different genotypes (inoculated or not) in pots containing a small compartment with (32)P-labelled soil accessible to AM fungal hyphae and determined expression of orthophosphate (P(i)) transporter genes involved in both AM and direct P uptake. *Gigaspora margarita increased WT competitive effects on rmc. WT and rmc inoculated with Glomus intraradices both showed growth depressions, which were mitigated when G. margarita was present. Orthophosphate transporter gene expression and (32)P transfer showed that the AM pathway operated in single inoculated WT, but not in rmc. *Effects of AM fungi on plant competition depended on the relative contributions of AM and direct pathways of P uptake. Glomus intraradices reduced the efficiency of direct uptake in both WT and rmc. The two-fungus combination showed that interactions between fungi are important in determining outcomes of plant competition.

Comparative genome analysis of Basidiomycete fungi

Energy Technology Data Exchange (ETDEWEB)

Riley, Robert; Salamov, Asaf; Henrissat, Bernard; Nagy, Laszlo; Brown, Daren; Held, Benjamin; Baker, Scott; Blanchette, Robert; Boussau, Bastien; Doty, Sharon L.; Fagnan, Kirsten; Floudas, Dimitris; Levasseur, Anthony; Manning, Gerard; Martin, Francis; Morin, Emmanuelle; Otillar, Robert; Pisabarro, Antonio; Walton, Jonathan; Wolfe, Ken; Hibbett, David; Grigoriev, Igor

2013-08-07

Fungi of the phylum Basidiomycota (basidiomycetes), make up some 37percent of the described fungi, and are important in forestry, agriculture, medicine, and bioenergy. This diverse phylum includes symbionts, pathogens, and saprotrophs including the majority of wood decaying and ectomycorrhizal species. To better understand the genetic diversity of this phylum we compared the genomes of 35 basidiomycetes including 6 newly sequenced genomes. These genomes span extremes of genome size, gene number, and repeat content. Analysis of core genes reveals that some 48percent of basidiomycete proteins are unique to the phylum with nearly half of those (22percent) found in only one organism. Correlations between lifestyle and certain gene families are evident. Phylogenetic patterns of plant biomass-degrading genes in Agaricomycotina suggest a continuum rather than a dichotomy between the white rot and brown rot modes of wood decay. Based on phylogenetically-informed PCA analysis of wood decay genes, we predict that that Botryobasidium botryosum and Jaapia argillacea have properties similar to white rot species, although neither has typical ligninolytic class II fungal peroxidases (PODs). This prediction is supported by growth assays in which both fungi exhibit wood decay with white rot-like characteristics. Based on this, we suggest that the white/brown rot dichotomy may be inadequate to describe the full range of wood decaying fungi. Analysis of the rate of discovery of proteins with no or few homologs suggests the value of continued sequencing of basidiomycete fungi.

The Genome Biology of Effector Gene Evolution in Filamentous Plant Pathogens.

Science.gov (United States)

Sánchez-Vallet, Andrea; Fouché, Simone; Fudal, Isabelle; Hartmann, Fanny E; Soyer, Jessica L; Tellier, Aurélien; Croll, Daniel

2018-05-16

Filamentous pathogens, including fungi and oomycetes, pose major threats to global food security. Crop pathogens cause damage by secreting effectors that manipulate the host to the pathogen's advantage. Genes encoding such effectors are among the most rapidly evolving genes in pathogen genomes. Here, we review how the major characteristics of the emergence, function, and regulation of effector genes are tightly linked to the genomic compartments where these genes are located in pathogen genomes. The presence of repetitive elements in these compartments is associated with elevated rates of point mutations and sequence rearrangements with a major impact on effector diversification. The expression of many effectors converges on an epigenetic control mediated by the presence of repetitive elements. Population genomics analyses showed that rapidly evolving pathogens show high rates of turnover at effector loci and display a mosaic in effector presence-absence polymorphism among strains. We conclude that effective pathogen containment strategies require a thorough understanding of the effector genome biology and the pathogen's potential for rapid adaptation. Expected final online publication date for the Annual Review of Phytopathology Volume 56 is August 25, 2018. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Effects of fungicides on endophytic fungi and photosynthesis in seedlings of a tropical tree, guarea guidonia (meliaceae)

International Nuclear Information System (INIS)

Gamboa Gaitan, Miguel A; Wen, Shiyun; Fetcher, Ned; Bayman, Paul

2005-01-01

Endophytes are microorganisms that live within healthy plant tissues, and include fungi and bacteria. They can be mutualists, comensals or even latent pathogens. Presence of these endosymbionts may affect host physiology, for example by consuming products of photosynthesis (endophytes are heterotrophs) or producing toxic metabolites. In this work two fungicides were used to eliminate fungal endophytes from seedlings of guarea guidonia. light saturated photosynthesis (Amax) was measured in endophytefree plants and compared with control plants. Each fungicide killed different fungal endosymbionts. phomopsis was more susceptible to benomyl while colletotrichum was more susceptible to propiconazole. Although suggestive, values of Amax were not significantly different for each treatment compared with control plants. No prediction can be made at this point about the final outcome of a given plantendophytic fungi interaction

Tomato immune receptor Ve1 recognizes effector of multiple fungal pathogens uncovered by genome and RNA sequencing

NARCIS (Netherlands)

Jonge, de R.; Esse, van H.P.; Maruthachalam, K.; Bolton, M.D.; Santhanam, P.; Keykha Saber, M.; Zhang, Z.; Usami, T.; Lievens, B.; Subbarao, K.V.; Thomma, B.

2012-01-01

Fungal plant pathogens secrete effector molecules to establish disease on their hosts, and plants in turn use immune receptors to try to intercept these effectors. The tomato immune receptor Ve1 governs resistance to race 1 strains of the soil-borne vascular wilt fungi Verticillium dahliae and

Diverse lifestyles and strategies of plant pathogenesis encoded in the genomes of eighteen Dothideomycetes fungi.

Directory of Open Access Journals (Sweden)

Robin A Ohm

Full Text Available The class Dothideomycetes is one of the largest groups of fungi with a high level of ecological diversity including many plant pathogens infecting a broad range of hosts. Here, we compare genome features of 18 members of this class, including 6 necrotrophs, 9 (hemibiotrophs and 3 saprotrophs, to analyze genome structure, evolution, and the diverse strategies of pathogenesis. The Dothideomycetes most likely evolved from a common ancestor more than 280 million years ago. The 18 genome sequences differ dramatically in size due to variation in repetitive content, but show much less variation in number of (core genes. Gene order appears to have been rearranged mostly within chromosomal boundaries by multiple inversions, in extant genomes frequently demarcated by adjacent simple repeats. Several Dothideomycetes contain one or more gene-poor, transposable element (TE-rich putatively dispensable chromosomes of unknown function. The 18 Dothideomycetes offer an extensive catalogue of genes involved in cellulose degradation, proteolysis, secondary metabolism, and cysteine-rich small secreted proteins. Ancestors of the two major orders of plant pathogens in the Dothideomycetes, the Capnodiales and Pleosporales, may have had different modes of pathogenesis, with the former having fewer of these genes than the latter. Many of these genes are enriched in proximity to transposable elements, suggesting faster evolution because of the effects of repeat induced point (RIP mutations. A syntenic block of genes, including oxidoreductases, is conserved in most Dothideomycetes and upregulated during infection in L. maculans, suggesting a possible function in response to oxidative stress.

Foliar aphid feeding recruits rhizosphere bacteria and primes plant immunity against pathogenic and non-pathogenic bacteria in pepper.

Science.gov (United States)

Lee, Boyoung; Lee, Soohyun; Ryu, Choong-Min

2012-07-01

Plants modulate defence signalling networks in response to different biotic stresses. The present study evaluated the effect of a phloem-sucking aphid on plant defence mechanisms in pepper (Capsicum annuum) during subsequent pathogen attacks on leaves and rhizosphere bacteria on roots. Plants were pretreated with aphids and/or the chemical trigger benzothiadiazol (BTH) 7 d before being challenged with two pathogenic bacteria, Xanthomonas axonopodis pv. vesicatoria (Xav) as a compatible pathogen and X. axonopodis pv. glycines (Xag) as an incompatible (non-host) pathogen. Disease severity was noticeably lower in aphid- and BTH + aphid-treated plants than in controls. Although treatment with BTH or aphids alone did not affect the hypersensitive response (HR) against Xag strain 8ra, the combination treatment had a synergistic effect on the HR. The aphid population was reduced by BTH pretreatment and by combination treatment with BTH and bacterial pathogens in a synergistic manner. Analysis of the expression of the defence-related genes Capsicum annum pathogenesis-related gene 9 (CaPR9), chitinase 2 (CaCHI2), SAR8·2 and Lipoxygenase1 (CaLOX1) revealed that aphid infestation resulted in the priming of the systemic defence responses against compatible and incompatible pathogens. Conversely, pre-challenge with the compatible pathogen Xav on pepper leaves significantly reduced aphid numbers. Aphid infestation increased the population of the beneficial Bacillus subtilis GB03 but reduced that of the pathogenic Ralstonia solanacearum SL1931. The expression of defence-related genes in the root and leaf after aphid feeding indicated that the above-ground aphid infestation elicited salicylic acid and jasmonic acid signalling throughout the whole plant. The findings of this study show that aphid feeding elicits plant resistance responses and attracts beneficial bacterial populations to help the plant cope with subsequent pathogen attacks.

Colletotrichum fungal pathogens and symbionts of ornamental nursery and landscape plants

Science.gov (United States)

Fungi in the ascomycete genus Colletotrichum are ranked by the plant pathology community as one of the ten most economically and scientifically important fungal phytopathogens. Major losses due to Colletotrichum are experienced in almost every crop worldwide, including nursery and landscape plants ...

Pathogenic Fungi Transmitted Through Cucumber Seeds and Safely Elimination by Application of Peppermint Extract and Oil

Directory of Open Access Journals (Sweden)

Eman S.H. FARRAG

2012-08-01

Full Text Available Diseases induced by Fusarium, like damping-off and wilt on cucumber, are serious problems around the world. Samples of cucumber seeds were collected from commercial markets in Egypt and tested for seed-borne fungi. In order to detect the maximum number of internal and external seed-borne fungi, agar plate examination of disinfected and non-disinfected seeds were used. Two species of Fusarium were the most frequent and predominant fungi. Facultative parasites of the genera Alternaria, Rhizoctonia, Helminthosporium and Penicillium were also found. A total 33 isolates of Fusarium spp. were obtained using Komadas selective medium. Fusarium oxysporum and F. solani were highly frequent. Pathogenicity test indicated that, F. oxysporum isolate (Fem8 was the main causal organism of pre- and post-emergence damping off. Furthermore, it occurred in all seed parts tested. Some infected seeds germinate, but they were either rapidly overgrown by F. oxysporum or they developed into a diseased seedling. The water extract of garlic, peppermint and rheum completely inhibited the conidiospore germination and mycelial growth of F. oxysporum at tested conc. 3, 2 and 3%, respectively. Soaked seeds in 2% peppermint extract and evaporated seeds by vapor of peppermint oil caused a highly reduction in the infection and reduced transmission of the referred fungi from seeds to the growing seedlings. The vigor of cucumber seedlings raised from the treated seeds was better than that developed from untreated ones.

Pathogenic Fungi Transmitted Through Cucumber Seeds and Safely Elimination by Application of Peppermint Extract and Oil

Directory of Open Access Journals (Sweden)

Eman S.H. FARRAG

2012-08-01

Full Text Available Diseases induced by Fusarium, like damping-off and wilt on cucumber, are serious problems around the world. Samples of cucumber seeds were collected from commercial markets in Egypt and tested for seed-borne fungi. In order to detect the maximum number of internal and external seed-borne fungi, agar plate examination of disinfected and non-disinfected seeds were used. Two species of Fusarium were the most frequent and predominant fungi. Facultative parasites of the genera Alternaria, Rhizoctonia, Helminthosporium and Penicillium were also found. A total 33 isolates of Fusarium spp. were obtained using Komada�s selective medium. Fusarium oxysporum and F. solani were highly frequent. Pathogenicity test indicated that, F. oxysporum isolate (Fem8 was the main causal organism of pre- and post-emergence damping off. Furthermore, it occurred in all seed parts tested. Some infected seeds germinate, but they were either rapidly overgrown by F. oxysporum or they developed into a diseased seedling. The water extract of garlic, peppermint and rheum completely inhibited the conidiospore germination and mycelial growth of F. oxysporum at tested conc. 3, 2 and 3%, respectively. Soaked seeds in 2% peppermint extract and evaporated seeds by vapor of peppermint oil caused a highly reduction in the infection and reduced transmission of the referred fungi from seeds to the growing seedlings. The vigor of cucumber seedlings raised from the treated seeds was better than that developed from untreated ones.

Rhizosphere Microbiome Recruited from a Suppressive Compost Improves Plant Fitness and Increases Protection against Vascular Wilt Pathogens of Tomato

Science.gov (United States)

Antoniou, Anastasis; Tsolakidou, Maria-Dimitra; Stringlis, Ioannis A.; Pantelides, Iakovos S.

2017-01-01

Suppressive composts represent a sustainable approach to combat soilborne plant pathogens and an alternative to the ineffective chemical fungicides used against those. Nevertheless, suppressiveness to plant pathogens and reliability of composts are often inconsistent with unpredictable effects. While suppressiveness is usually attributed to the compost’s microorganisms, the mechanisms governing microbial recruitment by the roots and the composition of selected microbial communities are not fully elucidated. Herein, the purpose of the study was to evaluate the impact of a compost on tomato plant growth and its suppressiveness against Fusarium oxysporum f. sp. lycopersici (Foxl) and Verticillium dahliae (Vd). First, growth parameters of tomato plants grown in sterile peat-based substrates including 20 and 30% sterile compost (80P/20C-ST and 70P/30C-ST) or non-sterile compost (80P/20C and 70P/30C) were evaluated in a growth room experiment. Plant height, total leaf surface, and fresh and dry weight of plants grown in the non-sterile compost mixes were increased compared to the plants grown in the sterile compost substrates, indicating the plant growth promoting activity of the compost’s microorganisms. Subsequently, compost’s suppressiveness against Foxl and Vd was evaluated with pathogenicity experiments on tomato plants grown in 70P/30C-ST and 70P/30C substrates. Disease intensity was significantly less in plants grown in the non-sterile compost than in those grown in the sterile compost substrate; AUDPC was 2.3- and 1.4-fold less for Foxl and Vd, respectively. Moreover, fungal quantification in planta demonstrated reduced colonization in plants grown in the non-sterile mixture. To further investigate these findings, we characterized the culturable microbiome attracted by the roots compared to the unplanted compost. Bacteria and fungi isolated from unplanted compost and the rhizosphere of plants were sequence-identified. Community-level analysis revealed

Characterization of non-host resistance in broad bean to the wheat stripe rust pathogen

Directory of Open Access Journals (Sweden)

Cheng Yulin

2012-06-01

Full Text Available Abstract Background Non-host resistance (NHR confers plant species immunity against the majority of microbial pathogens and represents the most robust and durable form of plant resistance in nature. As one of the main genera of rust fungi with economic and biological importance, Puccinia infects almost all cereals but is unable to cause diseases on legumes. Little is known about the mechanism of this kind of effective defense in legumes to these non-host pathogens. Results In this study, the basis of NHR in broad bean (Vicia faba L. against the wheat stripe rust pathogen, Puccinia striiformis f. sp. tritici (Pst, was characterized. No visible symptoms were observed on broad bean leaves inoculated with Pst. Microscopic observations showed that successful location of stomata and haustoria formation were significantly reduced in Pst infection of broad bean. Attempted infection induced the formation of papillae, cell wall thickening, production of reactive oxygen species, callose deposition and accumulation of phenolic compounds in plant cell walls. The few Pst haustoria that did form in broad bean cells were encased in reactive oxygen and callose materials and those cells elicited cell death. Furthermore, a total of seven defense-related genes were identified and found to be up-regulated during the Pst infection. Conclusions The results indicate that NHR in broad bean against Pst results from a continuum of layered defenses, including basic incompatibility, structural and chemical strengthening of cell wall, posthaustorial hypersensitive response and induction of several defense-related genes, demonstrating the multi-layered feature of NHR. This work also provides useful information for further determination of resistance mechanisms in broad bean to rust fungi, especially the adapted important broad bean rust pathogen, Uromyces viciae-fabae, because of strong similarity and association between NHR of plants to unadapted pathogens and basal

Plant pathogens structure arthropod communities across multiple spatial and temporal scales

NARCIS (Netherlands)

Tack, A.J.M.; Dicke, M.

2013-01-01

Plant pathogens and herbivores frequently co-occur on the same host plants. Despite this, little is known about the impact of their interactions on the structure of plant-based ecological communities. Here, we synthesize evidence that indicates that plant pathogens may profoundly impact arthropod

Plant response to biotic stress: Is there a common epigenetic response during plant-pathogenic and symbiotic interactions?

Science.gov (United States)

Zogli, Prince; Libault, Marc

2017-10-01

Plants constantly interact with pathogenic and symbiotic microorganisms. Recent studies have revealed several regulatory mechanisms controlling these interactions. Among them, the plant defense system is activated not only in response to pathogenic, but also in response to symbiotic microbes. Interestingly, shortly after symbiotic microbial recognition, the plant defense system is suppressed to promote plant infection by symbionts. Research studies have demonstrated the influence of the plant epigenome in modulating both pathogenic and symbiotic plant-microbe interactions, thereby influencing plant survival, adaptation and evolution of the plant response to microbial infections. It is however unclear if plant pathogenic and symbiotic responses share similar epigenomic profiles or if epigenomic changes differentially regulate plant-microbe symbiosis and pathogenesis. In this mini-review, we provide an update of the current knowledge of epigenomic control on plant immune responses and symbiosis, with a special attention being paid to knowledge gap and potential strategies to fill-in the missing links. Copyright © 2017 Elsevier B.V. All rights reserved.

Antagonism of rice phylloplane fungi against Cercospora oryzae

Science.gov (United States)

Mardani, A.; Hadiwiyono

2018-03-01

Narrow brown leaf spot (NBLS) caused by Cercospora oryzae Miyake is one of the important obstacle in rice cultivation that can decrease the productivity up to 40%. It has been known well that some phylloplane fungi are antagonistic to some leaf diseases. Phylloplane fungi of rice however haven’t been studied much and poorly understood as biological control agent of rice pathogen such C. oryzae. The research aimed to study the antagonism of some phylloplane fungi of rice against C. oryzae. At least 14 isolates of phylloplane fungi were collected which consisted of six pathogenic and eight nonpathogenic variants. All of nonpathogenic isolates were antagonistic against C. oryzae both in vitro and only one isolate could not inhibit the infection of the pathogen in vivo. Some isolates were identified as Aspergillus, Mucor, Penicillium, Fusarium, and Trichoderma. The isolate of Mucor and Fusarium could inhibit the highest growth of pathogen on potato dextrose medium that were at 36.0% and 35.5% respectively. Whereas on artificial inoculation on rice, some isolates such Penicillium and Fusarium could inhibit most effectively and were significantly different to Mencozeb application with dosage 5g L-1.

Photodynamic treatment with phenothiazinium photosensitizers kills both ungerminated and germinated microconidia of the pathogenic fungi Fusarium oxysporum, Fusarium moniliforme and Fusarium solani.

Science.gov (United States)

de Menezes, Henrique Dantas; Tonani, Ludmilla; Bachmann, Luciano; Wainwright, Mark; Braga, Gilberto Úbida Leite; von Zeska Kress, Marcia Regina

2016-11-01

The search for alternatives to control microorganisms is necessary both in clinical and agricultural areas. Antimicrobial photodynamic treatment (APDT) is a promising light-based approach that can be used to control both human and plant pathogenic fungi. In the present study, we evaluated the effects of photodynamic treatment with red light and four phenothiazinium photosensitizers (PS): methylene blue (MB), toluidine blue O (TBO), new methylene blue N (NMBN) and the phenothiazinium derivative S137 on ungerminated and germinated microconidia of Fusarium oxysporum, F. moniliforme, and F. solani. APDT with each PS killed efficiently both the quiescent ungerminated microconidia and metabolically active germinated microconidia of the three Fusarium species. Washing away the unbound PS from the microconidia (both ungerminated and germinated) before red light exposure reduced but did not prevent the effect of APDT. Subcelullar localization of PS in ungerminated and germinated microconidia and the effects of photodynamic treatment on cell membranes were also evaluated in the three Fusarium species. APDT with MB, TBO, NMBN or S137 increased the membrane permeability in microconidia and APDT with NMBN or S137 increased the lipids peroxidation in microconidia of the three Fusarium species. These findings expand the understanding of photodynamic inactivation of filamentous fungi with phenothiazinium PS. Copyright © 2016 Elsevier B.V. All rights reserved.

Convergent Evolution of Pathogen Effectors toward Reactive Oxygen Species Signaling Networks in Plants.

Science.gov (United States)

Jwa, Nam-Soo; Hwang, Byung Kook

2017-01-01

Microbial pathogens have evolved protein effectors to promote virulence and cause disease in host plants. Pathogen effectors delivered into plant cells suppress plant immune responses and modulate host metabolism to support the infection processes of pathogens. Reactive oxygen species (ROS) act as cellular signaling molecules to trigger plant immune responses, such as pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) and effector-triggered immunity. In this review, we discuss recent insights into the molecular functions of pathogen effectors that target multiple steps in the ROS signaling pathway in plants. The perception of PAMPs by pattern recognition receptors leads to the rapid and strong production of ROS through activation of NADPH oxidase Respiratory Burst Oxidase Homologs (RBOHs) as well as peroxidases. Specific pathogen effectors directly or indirectly interact with plant nucleotide-binding leucine-rich repeat receptors to induce ROS production and the hypersensitive response in plant cells. By contrast, virulent pathogens possess effectors capable of suppressing plant ROS bursts in different ways during infection. PAMP-triggered ROS bursts are suppressed by pathogen effectors that target mitogen-activated protein kinase cascades. Moreover, pathogen effectors target vesicle trafficking or metabolic priming, leading to the suppression of ROS production. Secreted pathogen effectors block the metabolic coenzyme NADP-malic enzyme, inhibiting the transfer of electrons to the NADPH oxidases (RBOHs) responsible for ROS generation. Collectively, pathogen effectors may have evolved to converge on a common host protein network to suppress the common plant immune system, including the ROS burst and cell death response in plants.

Convergent Evolution of Pathogen Effectors toward Reactive Oxygen Species Signaling Networks in Plants

Directory of Open Access Journals (Sweden)

Nam-Soo Jwa

2017-09-01

Full Text Available Microbial pathogens have evolved protein effectors to promote virulence and cause disease in host plants. Pathogen effectors delivered into plant cells suppress plant immune responses and modulate host metabolism to support the infection processes of pathogens. Reactive oxygen species (ROS act as cellular signaling molecules to trigger plant immune responses, such as pathogen-associated molecular pattern (PAMP-triggered immunity (PTI and effector-triggered immunity. In this review, we discuss recent insights into the molecular functions of pathogen effectors that target multiple steps in the ROS signaling pathway in plants. The perception of PAMPs by pattern recognition receptors leads to the rapid and strong production of ROS through activation of NADPH oxidase Respiratory Burst Oxidase Homologs (RBOHs as well as peroxidases. Specific pathogen effectors directly or indirectly interact with plant nucleotide-binding leucine-rich repeat receptors to induce ROS production and the hypersensitive response in plant cells. By contrast, virulent pathogens possess effectors capable of suppressing plant ROS bursts in different ways during infection. PAMP-triggered ROS bursts are suppressed by pathogen effectors that target mitogen-activated protein kinase cascades. Moreover, pathogen effectors target vesicle trafficking or metabolic priming, leading to the suppression of ROS production. Secreted pathogen effectors block the metabolic coenzyme NADP-malic enzyme, inhibiting the transfer of electrons to the NADPH oxidases (RBOHs responsible for ROS generation. Collectively, pathogen effectors may have evolved to converge on a common host protein network to suppress the common plant immune system, including the ROS burst and cell death response in plants.

Changes in carbon footprint when integrating production of filamentous fungi in 1st generation ethanol plants.

Science.gov (United States)

Brancoli, Pedro; Ferreira, Jorge A; Bolton, Kim; Taherzadeh, Mohammad J

2018-02-01

Integrating the cultivation of edible filamentous fungi in the thin stillage from ethanol production is presently being considered. This integration can increase the ethanol yield while simultaneously producing a new value-added protein-rich biomass that can be used for animal feed. This study uses life cycle assessment to determine the change in greenhouse gas (GHG) emissions when integrating the cultivation of filamentous fungi in ethanol production. The result shows that the integration performs better than the current scenario when the fungal biomass is used as cattle feed for system expansion and when energy allocation is used. It performs worse if the biomass is used as fish feed. Hence, integrating the cultivation of filamentous fungi in 1st generation ethanol plants combined with proper use of the fungi can lead to a reduction of GHG emissions which, considering the number of existing ethanol plants, can have a significant global impact. Copyright © 2017 Elsevier Ltd. All rights reserved.

Chromatin versus pathogens: the function of epigenetics in plant immunity

Science.gov (United States)

Ding, Bo; Wang, Guo-Liang

2015-01-01

To defend against pathogens, plants have developed a sophisticated innate immunity that includes effector recognition, signal transduction, and rapid defense responses. Recent evidence has demonstrated that plants utilize the epigenetic control of gene expression to fine-tune their defense when challenged by pathogens. In this review, we highlight the current understanding of the molecular mechanisms of histone modifications (i.e., methylation, acetylation, and ubiquitination) and chromatin remodeling that contribute to plant immunity against pathogens. Functions of key histone-modifying and chromatin remodeling enzymes are discussed. PMID:26388882

Diversity of leaf endophytic fungi in mangrove plants of northeast Brazil

Science.gov (United States)

Wanderley Costa, Isabella P. M.; Maia, Leonor Costa; Cavalcanti, Maria Auxiliadora

2012-01-01

With the aim of increasing the knowledge about endophytic fungi, a group of microorganisms with high biotechnological potential and a valuable source of useful metabolites, a survey in leaves of mangrove plants (Avicennia schaueriana, Laguncularia racemosa, and Rhizophora mangle) was performed at the Itamaracá Island, PE, Brazil. Leaves were collected, during two seasons, dry and rainy, superficially sterilized and fragments maintained in Petri dishes with Potato dextrose agar (PDA) at 28o ± 2o C until isolation of the fungi. Fourty taxa were isolated: 25 species representing 19 genera and 15 morphotypes determined as Mycelia sterilia. Leaves of L. racemosa hosted the highest number of colony forming units (CFU) and taxa. Guignardia sp. and Colletotrichum gloeosporioides were the most frequently isolated, while Glomerella cingulata was the only species found in association with the three host plants. The proportional importance of each fungus differed among hosts. The similarity of fungi species between the two seasons reached only 4.2%, and that between the hosts was also low, with the maximum (A. schaueriana x L. racemosa) reaching 24.2%. Sphaerosporium, as well as Chloridium virescens var. virescens, Microsphaeropsis arundinis, Penicillium pinophilum, Periconia cambrensis, Phoma herbarum, P. diachenii, P. obscurans, Sordaria prolifica and Torula elisii are reported for the first time as endophytic in tropical regions. PMID:24031941

Diversity of leaf endophytic fungi in mangrove plants of Northeast Brazil

Directory of Open Access Journals (Sweden)

Isabella P. M. Wanderley Costa

2012-09-01

Full Text Available With the aim of increasing the knowledge about endophytic fungi, a group of microorganisms with high biotechnological potential and a valuable source of useful metabolites, a survey in leaves of mangrove plants (Avicennia schaueriana, Laguncularia racemosa, and Rhizophora mangle was performed at the Itamaracá Island, PE, Brazil. Leaves were collected, during two seasons, dry and rainy, superficially sterilized and fragments maintained in Petri dishes with Potato dextrose agar (PDA at 28º ± 2º C until isolation of the fungi. Fourty taxa were isolated: 25 species representing 19 genera and 15 morphotypes determined as Mycelia sterilia. Leaves of L. racemosa hosted the highest number of colony forming units (CFU and taxa. Guignardia sp. and Colletotrichum gloeosporioides were the most frequently isolated, while Glomerella cingulata was the only species found in association with the three host plants. The proportional importance of each fungus differed among hosts. The similarity of fungi species between the two seasons reached only 4.2%, and that between the hosts was also low, with the maximum (A. schaueriana x L. racemosa reaching 24.2%. Sphaerosporium, as well as Chloridium virescens var. virescens, Microsphaeropsis arundinis, Penicillium pinophilum, Periconia cambrensis, Phoma herbarum, P. diachenii, P. obscurans, Sordaria prolifica and Torula elisii are reported for the first time as endophytic in tropical regions.

Cell-to-cell communication in plants, animals, and fungi: a comparative review.

Science.gov (United States)

Bloemendal, Sandra; Kück, Ulrich

2013-01-01

Cell-to-cell communication is a prerequisite for differentiation and development in multicellular organisms. This communication has to be tightly regulated to ensure that cellular components such as organelles, macromolecules, hormones, or viruses leave the cell in a precisely organized way. During evolution, plants, animals, and fungi have developed similar ways of responding to this biological challenge. For example, in higher plants, plasmodesmata connect adjacent cells and allow communication to regulate differentiation and development. In animals, two main general structures that enable short- and long-range intercellular communication are known, namely gap junctions and tunneling nanotubes, respectively. Finally, filamentous fungi have also developed specialized structures called septal pores that allow intercellular communication via cytoplasmic flow. This review summarizes the underlying mechanisms for intercellular communication in these three eukaryotic groups and discusses its consequences for the regulation of differentiation and developmental processes.

Beneficial interactions between plants and soil microbes

DEFF Research Database (Denmark)

Ravnskov, S.

2012-01-01

with Arbuscular Mycorrhizal Fungi (AMF); thus the relation between root pathogens and most plants under field conditions is an interaction between AM and pathogens. The AM symbiosis has functionally been characterised as the reciprocal exchange of nutrients between the symbionts: the fungus is obligate biotrophic......The microbial community in the rhizosphere plays a key role in plant growth and -health, either directly by influencing plant nutrient uptake and by causing disease, or indirectly via microbial interactions in the rhizosphere. The majority of field grown crops (70-80 %) naturally form symbiosis...

Long-term effects of single potassium fertilization on 137Cs levels in plants and fungi in a boreal forest ecosystem

International Nuclear Information System (INIS)

Rosen, K.; Vinichuk, M.; Nikolova, I.; Johanson, K.

2011-01-01

We examined the long-term effects of a single application of potassium (K) fertilizer (100 kg K ha -1 ) in 1992 on 137 Cs uptake in a forest ecosystem in central Sweden. 137 Cs activity concentrations were determined in three low-growing perennial shrubs, heather (Calluna vulgaris), lingonberry (Vaccinium vitis-idaea) and bilberry (Vaccinium myrtillus), and in four wild fungal species (Cortinarius semisanguineus, Lactarius rufus, Rozites caperata and Suillus variegatus). Uptake of 137 Cs by plants and fungi growing on K-fertilized plots 17 years after application of the K fertilizer was significantly lower than in corresponding species growing in a non-fertilized control area. The 137 Cs activity concentration was 21-58% lower in fungal sporocarps and 40-61% lower in plants in the K-fertilized area compared with the control. Over the study period, this decrease in 137 Cs activity concentration was more consistent in plants than in fungi, although the effect was statistically significant and strongly pronounced in all species. The effect of K fertilization in reducing 137 Cs activity concentration in fungi and plants decreased over time but was still significant in 2009, 17 years after fertilization. This suggests that application of K fertilizer to forests is an appropriate and effective long-term measure to decrease radiocaesium accumulation in plants and fungi. - Research highlights: → Effects of potassium fertilizer on 137 Cs uptake by plants and fungi are investigated. → 137 Cs activity concentrations in forest plants decreased even within the first year. → The most significant reduction occurred over the first 7-8 years. → The reduction in fungi was less pronounced, but still statistically significant.

Impact of vector dispersal and host-plant fidelity on the dissemination of an emerging plant pathogen.

Directory of Open Access Journals (Sweden)

Jes Johannesen

Full Text Available Dissemination of vector-transmitted pathogens depend on the survival and dispersal of the vector and the vector's ability to transmit the pathogen, while the host range of vector and pathogen determine the breath of transmission possibilities. In this study, we address how the interaction between dispersal and plant fidelities of a pathogen (stolbur phytoplasma tuf-a and its vector (Hyalesthes obsoletus: Cixiidae affect the emergence of the pathogen. Using genetic markers, we analysed the geographic origin and range expansion of both organisms in Western Europe and, specifically, whether the pathogen's dissemination in the northern range is caused by resident vectors widening their host-plant use from field bindweed to stinging nettle, and subsequent host specialisation. We found evidence for common origins of pathogen and vector south of the European Alps. Genetic patterns in vector populations show signals of secondary range expansion in Western Europe leading to dissemination of tuf-a pathogens, which might be newly acquired and of hybrid origin. Hence, the emergence of stolbur tuf-a in the northern range was explained by secondary immigration of vectors carrying stinging nettle-specialised tuf-a, not by widening the host-plant spectrum of resident vectors with pathogen transmission from field bindweed to stinging nettle nor by primary co-migration from the resident vector's historical area of origin. The introduction of tuf-a to stinging nettle in the northern range was therefore independent of vector's host-plant specialisation but the rapid pathogen dissemination depended on the vector's host shift, whereas the general dissemination elsewhere was linked to plant specialisation of the pathogen but not of the vector.

The arable plant ecosystem as battleground for emergence of human pathogens

Directory of Open Access Journals (Sweden)

Leo eVan Overbeek

2014-03-01

Full Text Available Disease incidences related to Escherichia coli and Salmonella enterica infections by consumption of (fresh vegetables, sprouts and occasionally fruits made clear that these pathogens are not only transmitted to humans via the ‘classical’ routes of meat, eggs and dairy products, but also can be transmitted to humans via plants or products derived from plants. Nowadays, it is of major concern that these human pathogens, especially the ones belonging to the taxonomical family of Enterobacteriaceae, become adapted to environmental habitats without losing their virulence to humans. Adaptation to the plant environment would lead to longer persistence in plants, increasing their chances on transmission to humans via consumption of plant-derived food. One of the mechanisms of adaptation to the plant environment in human pathogens, proposed in this paper, is horizontal transfer of genes from different microbial communities present in the arable ecosystem, like the ones originating from soil, animal digestive track systems (manure, water and plants themselves. Genes that would confer better adaptation to the phytosphere might be genes involved in plant colonization, stress resistance and nutrient acquisition and utilization. Because human pathogenic enterics often were prone to genetic exchanges via phages and conjugative plasmids, it was postulated that these genetic elements may be hold key responsible for horizontal gene transfers between human pathogens and indigenous microbes in agroproduction systems. In analogy to zoonosis, we coin the term phytonosis for a human pathogen that is transmitted via plants and not exclusively via animals.

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

African Journals Online (AJOL)

Background: Plant fungal pathogens play a crucial role in the profitability, quality and quantity of plant production. These phytopathogens are persistent in avoiding plant defences causing diseases and quality losses around the world that amount to billions of US dollars annually. To control the scourge of plant fungal ...

Induced release of a plant-defense volatile 'deceptively' attracts insect vectors to plants infected with a bacterial pathogen.

Directory of Open Access Journals (Sweden)

Rajinder S Mann

Full Text Available Transmission of plant pathogens by insect vectors is a complex biological process involving interactions between the plant, insect, and pathogen. Pathogen-induced plant responses can include changes in volatile and nonvolatile secondary metabolites as well as major plant nutrients. Experiments were conducted to understand how a plant pathogenic bacterium, Candidatus Liberibacter asiaticus (Las, affects host preference behavior of its psyllid (Diaphorina citri Kuwayama vector. D. citri were attracted to volatiles from pathogen-infected plants more than to those from non-infected counterparts. Las-infected plants were more attractive to D. citri adults than non-infected plants initially; however after feeding, psyllids subsequently dispersed to non-infected rather than infected plants as their preferred settling point. Experiments with Las-infected and non-infected plants under complete darkness yielded similar results to those recorded under light. The behavior of psyllids in response to infected versus non-infected plants was not influenced by whether or not they were carriers of the pathogen. Quantification of volatile release from non-infected and infected plants supported the hypothesis that odorants mediate psyllid preference. Significantly more methyl salicylate, yet less methyl anthranilate and D-limonene, was released by infected than non-infected plants. Methyl salicylate was attractive to psyllids, while methyl anthranilate did not affect their behavior. Feeding on citrus by D. citri adults also induced release of methyl salicylate, suggesting that it may be a cue revealing location of conspecifics on host plants. Infected plants were characterized by lower levels of nitrogen, phosphorus, sulfur, zinc, and iron, as well as, higher levels of potassium and boron than non-infected plants. Collectively, our results suggest that host selection behavior of D. citri may be modified by bacterial infection of plants, which alters release of

EPCOT, NASA and plant pathogens in space.

Science.gov (United States)

White, R

1996-01-01

Cooperative work between NASA and Walt Disney World's EPCOT Land Pavilion is described. Joint efforts include research about allelopathy in multi-species plant cropping in CELSS, LEDs as light sources in hydroponic systems, and the growth of plant pathogens in space.

Evolutionary genomics revealed interkingdom distribution of Tcn1-like chromodomain-containing Gypsy LTR retrotransposons among fungi and plants

Directory of Open Access Journals (Sweden)

Blinov Alexander

2010-04-01

Full Text Available Abstract Background Chromodomain-containing Gypsy LTR retrotransposons or chromoviruses are widely distributed among eukaryotes and have been found in plants, fungi and vertebrates. The previous comprehensive survey of chromoviruses from mosses (Bryophyta suggested that genomes of non-seed plants contain the clade which is closely related to the retrotransposons from fungi. The origin, distribution and evolutionary history of this clade remained unclear mainly due to the absence of information concerning the diversity and distribution of LTR retrotransposons in other groups of non-seed plants as well as in fungal genomes. Results In present study we preformed in silico analysis of chromodomain-containing LTR retrotransposons in 25 diverse fungi and a number of plant species including spikemoss Selaginella moellendorffii (Lycopodiophyta coupled with an experimental survey of chromodomain-containing Gypsy LTR retrotransposons from diverse non-seed vascular plants (lycophytes, ferns, and horsetails. Our mining of Gypsy LTR retrotransposons in genomic sequences allowed identification of numerous families which have not been described previously in fungi. Two new well-supported clades, Galahad and Mordred, as well as several other previously unknown lineages of chromodomain-containing Gypsy LTR retrotransposons were described based on the results of PCR-mediated survey of LTR retrotransposon fragments from ferns, horsetails and lycophytes. It appeared that one of the clades, namely Tcn1 clade, was present in basidiomycetes and non-seed plants including mosses (Bryophyta and lycophytes (genus Selaginella. Conclusions The interkingdom distribution is not typical for chromodomain-containing LTR retrotransposons clades which are usually very specific for a particular taxonomic group. Tcn1-like LTR retrotransposons from fungi and non-seed plants demonstrated high similarity to each other which can be explained by strong selective constraints and the