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J.m. Whipps - One of the best experts on this subject based on the ideXlab platform.
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antimicrobial activity of Coniothyrium minitans and its macrolide antibiotic macrosphelide a
Journal of Applied Microbiology, 2009Co-Authors: Nicola Tomprefa, Robert A. Hill, Mark P Mcquilken, J.m. WhippsAbstract:Aims: Assessment of antimicrobial activity of the mycoparasite Coniothyrium minitans and its macrolide antibiotic macrosphelide A. Methods and Results: Thirteen isolates of C. minitans were tested for ability to inhibit a number of filamentous fungi, yeasts, oomycetes and bacteria in agar based tests. Activity was found against some ascomycetes, basidiomycetes, oomycetes and Gram-positive bacteria, but not against zygomycetes, yeasts or Gram-negative bacteria tested. Six C. minitans isolates (Conio, Contans, IVT1, CM/AP/3118, B279/1, A1/327/1) were found to produce macrosphelide A in liquid culture and no other antibiotics were detected. On agar, macrosphelide A inhibited growth of some ascomycetes, basidiomycetes, oomycetes and all four Gram-positive bacteria tested, including the medically important Staphylococcus aureus with a minimum inhibitory concentration of ≤500 μg ml−1. There was no inhibition observed against the yeasts and Gram-negative bacteria when macrosphelide A was tested at 700 μg ml−1. Conclusions: The spectrum and level of activity of macrosphelide A produced by C. minitans against micro-organisms are extended markedly compared to previous reports. Significance and Impact of the Study: Macrosphelide A was effective against Staph. aureus. Further study on the control of this bacterium is merited in view of the development of antibiotic resistance.
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characterization of sclerotinia and mycoparasite Coniothyrium minitans interaction by microscale co culture
Letters in Applied Microbiology, 2008Co-Authors: S.n. Smith, Mark Prince, J.m. WhippsAbstract:Aims: To characterize the interaction of Sclerotinia sclerotiorum and S. minor with strains of the mycoparasite and commercial biocontrol agent Coniothyrium minitans using novel perfusion chamber gasket co-culture. Methods and Results: Sclerotinia were cultured in perfusion chamber gaskets and then flooded with Coniothyrium conidia. After germination, Coniothyrium failed to show any form of directed growth, making contact with Sclerotinia hyphae in a random manner. In turn, some Coniothyrium hyphae coiled round Sclerotinia counterparts and although no intracellular growth was observed, Coniothyrium proliferated, while the hyphae of Sclerotinia became vacuolated and lost the cytoplasm. When co-cultures of Sclerotinia with Coniothyrium were flooded with FITC-lectins, small difference in fluorescence between the fungi was found with FITC-Con A suggesting that cell walls of both the species exposed mannose. In contrast, Coniothyrium fluoresced poorly in comparison with Sclerotinia when FITC-wheat germ agglutinin was used, indicating a marked paucity of N-acetylglucosamine exposure by cell walls of Coniothyrium, hence reduced exposure to chitinolytic enzyme action. Conclusions, Significance and Impact of the Study: The approach employed supported direct sequential microscopic observation of Coniothyrium and Sclerotinia as well as the utilization of representative fluorescent moieties to characterize relative carbohydrate cell wall exposure.
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disruption of the Coniothyrium minitans pif1 dna helicase gene impairs growth and capacity for sclerotial mycoparasitism
Microbiology, 2008Co-Authors: Chris Rogers, Mike Challen, S. Muthumeenakshi, Surapareddy Sreenivasaprasad, J.m. WhippsAbstract:A non-mycoparasitic restriction enzyme-mediated DNA integration (REMI) mutant of Coniothyrium minitans (R2427) contains two tandem plasmid copies integrated towards the 3′ end of an ORF. The predicted polypeptide (845 aa) exhibits high similarity with DNA-helicase proteins from other filamentous fungi and yeasts that play a role in mitochondrial DNA maintenance and repair. Disruption of the C. minitans PIF1 DNA helicase gene results in altered morphology, reduced growth rates and a concomitant loss in ability to mycoparasitize sclerotia of Sclerotinia sclerotiorum. In infection bioassays, R2427 exhibited sparse mycelial growth on the surface of live sclerotia, but no mycelia were detected inside the sclerotia. Conversely, R2427 readily colonized autoclaved sclerotia. Complementation of the mutant with wild-type PIF1 restored normal mycelial growth and mycoparasitic capability, confirming a functional role in the host–pathogen interaction. The C. minitans PIF1 DNA helicase may maintain mitochondrial stability in response to reactive oxygen species, either produced endogenously within the mycoparasite, or exogenously from the sclerotial host.
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use of Coniothyrium minitans as a biocontrol agent and some molecular aspects of sclerotial mycoparasitism
European Journal of Plant Pathology, 2008Co-Authors: J.m. Whipps, Chris Rogers, S. Muthumeenakshi, Surapareddy Sreenivasaprasad, Mike ChallenAbstract:The use of the sclerotial mycoparasite Coniothyrium minitans as a biological control agent of diseases caused by sclerotium-forming pathogens especially Sclerotinia sclerotiorum is briefly reviewed. A number of studies have examined production and application methods, integrated control, ecology, and modes of action in order to understand the biology of the mycoparasite and enhance activity and reproducibility of use. Recently, development of a number of molecular-based techniques has begun to allow the examination of genes involved in mycoparasitism. Some of these procedures have been applied to identify pathogenicity genes involved in the infection of sclerotia of S. sclerotiorum by C. minitans and this work is discussed.
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analysis of cdna transcripts from Coniothyrium minitans reveals a diverse array of genes involved in key processes during sclerotial mycoparasitism
Fungal Genetics and Biology, 2007Co-Authors: S. Muthumeenakshi, Mike Challen, Chris Rogers, Surapareddy Sreenivasaprasad, J.m. WhippsAbstract:Coniothyrium minitans colonises and destroys the sclerotia of Sclerotinia sclerotiorum in nature exhibiting ecologically obligate mycoparasitism as its spores remain dormant in soil and only grow actively in the presence of the sclerotia. Molecular mechanisms underlying sclerotial mycoparasitism are poorly defined. We identified 251 unisequences representing genes preferentially expressed by C. minitans during sclerotial mycoparasitism, substantially increasing the molecular knowledge of this commercially important biocontrol agent. Genes associated with signalling and cellular communication, degradation of host cell walls and energy reserves, nutrient utilisation, detoxification and stress response were identified suggesting that C. minitans employs a number of key processes during host colonisation. Several of these genes are novel to fungal-fungal interactions (e.g. PTH11-like GPCR and the ETP gene cluster). Secretin receptor-like GPCR and the TGF-beta signalling system have not yet been characterised in filamentous fungi. This study provides the basis for in-depth gene function analysis in sclerotial mycoparasitism.
Mahmoud Fahmi Elsebai - One of the best experts on this subject based on the ideXlab platform.
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unusual nitrogenous phenalenone derivatives from the marine derived fungus Coniothyrium cereale
Molecules, 2016Co-Authors: Mahmoud Fahmi Elsebai, Hazem A Ghabbour, Mohamed MehiriAbstract:The new phenalenone metabolites 1, 2, 4, and 6 were isolated from the marine-derived endophytic fungus Coniothyrium cereale, in addition to the ergostane-type sterol (3) and entatrovenetinone (5). Compounds 1 and 2 represent two unusual nitrogen-containing compounds, which are composed of a sterol portion condensed via two bonds to phenalenone derivatives. Compound 6, which contains unprecedented imine functionality between two carbonyl groups to form a oxepane -imine-dione ring, exhibited a moderate cytotoxicity against K562, U266, and SKM1 cancer cell lines. Moreover, molecular docking studies were done on estrogen receptor α-ligand binding domain (ERα-LBD) to compounds 1 and 2 to correlate with binding energies and affinities calculated from molecular docking to the anti-proliferative activity.
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polyketide skeletons from the marine alga derived fungus Coniothyrium cereale
European Journal of Organic Chemistry, 2012Co-Authors: Mamona Nazir, Stefan Kehraus, Ekaterina Egereva, Mahmoud Fahmi Elsebai, Michael Gutschow, Karine Ndjoko Ioset, Laurence Marcourt, Damien Jeannerat, Jeanluc WolfenderAbstract:The fungus Coniothyrium cereale was isolated from the Baltic Sea alga Enteromorpha sp. Upon cultivation in saline medium, C. cereale produced the structurally unprecedented isoindole pseudoalkaloid conioimide (1) and the polyketide cereoanhydride (2). Because of the very limited amount of compounds isolated, the structures of 1 and 2 were established from extensive NMR spectroscopic and mass spectrometric analyses, and in the case of 1, the structural analysis was completed by NMR shielding calculations. Conioimide and cereoanhydride represent new structural types of polyketides. Experiments with 13C-labeled acetate proved the polyketide nature of the major and known C. cereale metabolite (–)-trypethelone (3), which is proposed to be the precursor of cereoanhydride. Conioimide has prominent and selective inhibitory activity towards the protease human leukocyte elastase (HLE), an enzyme involved in many inflammatory diseases, with an IC50 (half maximal inhibitory concentration) value of 0.2 μg mL–1.
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hle inhibitory alkaloids with a polyketide skeleton from the marine derived fungus Coniothyrium cereale
Journal of Natural Products, 2011Co-Authors: Stefan Kehraus, Mahmoud Fahmi Elsebai, Lavanya Natesan, Ietidal Mohamed, Gregor Schnakenburg, Florenz Sasse, Saad Shaaban, Michael Gutschow, Gabriele M. KönigAbstract:The marine endophytic fungus Coniothyrium cereale produces the structu- rallyunusualpolyketide-typealkaloids(� )-cereolactam(1)and(� )-cereoaldomine(3), incorporating a lactam and an imine functionality, respectively, as well as the related metabolite (� )-trypethelone (2). Compounds 1 and 3 showed selective inhibition of human leukocyte elastase with IC50values of 9.28 and 3.01 μM, respectively. Compound 2 was found to be inhibitory toward Mycobacterium phlei, Staphylococcus aureus, and Escherichia coli and also cytotoxic against mouse fibroblast cells (IC50 = 7.5 μM).
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antimicrobial phenalenone derivatives from the marine derived fungus Coniothyrium cereale
Organic and Biomolecular Chemistry, 2011Co-Authors: Mahmoud Fahmi Elsebai, Stefan Kehraus, Florenz Sasse, Saad Shaaban, Michael Gutschow, Ulrike Lindequist, Michaele Josten, Hansgeorg Sahl, Gabriele M. KönigAbstract:The marine-derived fungus Coniothyrium cereale was isolated from the green alga Enteromorpha sp. and found to produce the new phenalenone derivatives 1–7 as well as the known compounds lactone 8, (−) sclerodin (9), lamellicolic anhydride (10), (−) scleroderolide (11), and (−) sclerodione (12). The structures of these closely related compounds were established from extensive spectroscopic investigations on the basis of one and two dimensional NMR spectroscopic studies (1H, 13C, COSY, NOESY, HSQC and HMBC) as well as mass spectrometric analysis (LC/MS, HREIMS and HRESIMS), UV and IR spectra. Compounds 5 and 11 showed the same antimicrobial activity toward Staphylococcus aureus SG 511 with an MIC value of 24 μM. The presence of a diketo-lactone ring as in compounds 5 and 11 was found to be essential for this activity. In agar diffusion assays with Mycobacterium phlei considerable inhibition zones were observed for compounds 2, 4 and 7. Compounds 1, 5 and 9 showed potent inhibition of human leukocyte elastase (HLE) with IC50 values of 7.2, 13.3 and 10.9 μM, respectively.
Gabriele M. König - One of the best experts on this subject based on the ideXlab platform.
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Phenalenones: insight into the biosynthesis of polyketides from the marine alga-derived fungus Coniothyrium cereale.
Organic & biomolecular chemistry, 2015Co-Authors: Mamona Nazir, Fayrouz El Maddah, Stefan Kehraus, Ekaterina Egereva, Jörn Piel, Alexander O. Brachmann, Gabriele M. KönigAbstract:The marine alga-derived fungus Coniothyrium cereale is a prolific producer of phenalenones. These polyketides were shown to possess antimicrobial effects and inhibitory activity towards the protease human leucocyte elastase (HLE). The current study focused on the biosynthesis of eight different structural types of phenalenones, comprising the natural products rousselianone A′ (1), coniosclerodin (3), cereolactam (12), cereoaldomine (15), and trypethelone (16). Solid agar cultures of C. cereale were used to follow up the incorporation of [1-13C] labeled acetate into these metabolites. Taking the respective mechanisms of polyketide metabolism into account, the labeling pattern was interpreted, thus providing a hypothesis for the biosynthetic formation of the phenalenones. The polyketide skeleton of the phenanthrene-based compound cereolactam is proposed to be formed through degradation of a heptaketide by loss of two carbon atoms.
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hle inhibitory alkaloids with a polyketide skeleton from the marine derived fungus Coniothyrium cereale
Journal of Natural Products, 2011Co-Authors: Stefan Kehraus, Mahmoud Fahmi Elsebai, Lavanya Natesan, Ietidal Mohamed, Gregor Schnakenburg, Florenz Sasse, Saad Shaaban, Michael Gutschow, Gabriele M. KönigAbstract:The marine endophytic fungus Coniothyrium cereale produces the structu- rallyunusualpolyketide-typealkaloids(� )-cereolactam(1)and(� )-cereoaldomine(3), incorporating a lactam and an imine functionality, respectively, as well as the related metabolite (� )-trypethelone (2). Compounds 1 and 3 showed selective inhibition of human leukocyte elastase with IC50values of 9.28 and 3.01 μM, respectively. Compound 2 was found to be inhibitory toward Mycobacterium phlei, Staphylococcus aureus, and Escherichia coli and also cytotoxic against mouse fibroblast cells (IC50 = 7.5 μM).
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antimicrobial phenalenone derivatives from the marine derived fungus Coniothyrium cereale
Organic and Biomolecular Chemistry, 2011Co-Authors: Mahmoud Fahmi Elsebai, Stefan Kehraus, Florenz Sasse, Saad Shaaban, Michael Gutschow, Ulrike Lindequist, Michaele Josten, Hansgeorg Sahl, Gabriele M. KönigAbstract:The marine-derived fungus Coniothyrium cereale was isolated from the green alga Enteromorpha sp. and found to produce the new phenalenone derivatives 1–7 as well as the known compounds lactone 8, (−) sclerodin (9), lamellicolic anhydride (10), (−) scleroderolide (11), and (−) sclerodione (12). The structures of these closely related compounds were established from extensive spectroscopic investigations on the basis of one and two dimensional NMR spectroscopic studies (1H, 13C, COSY, NOESY, HSQC and HMBC) as well as mass spectrometric analysis (LC/MS, HREIMS and HRESIMS), UV and IR spectra. Compounds 5 and 11 showed the same antimicrobial activity toward Staphylococcus aureus SG 511 with an MIC value of 24 μM. The presence of a diketo-lactone ring as in compounds 5 and 11 was found to be essential for this activity. In agar diffusion assays with Mycobacterium phlei considerable inhibition zones were observed for compounds 2, 4 and 7. Compounds 1, 5 and 9 showed potent inhibition of human leukocyte elastase (HLE) with IC50 values of 7.2, 13.3 and 10.9 μM, respectively.
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three new metabolites from marine derived fungi of the genera Coniothyrium and microsphaeropsis
Journal of Natural Products, 1999Co-Authors: Ulrich Holler, Gabriele M. König, Anthony D WrightAbstract:The marine sponges Ectyplasia perox and Myxilla incrustans were investigated for associated fungal strains. Among others, a Coniothyrium sp., from E. perox, and a Microsphaeropsis sp., from M. incr...
Karsten Krohn - One of the best experts on this subject based on the ideXlab platform.
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structural and stereochemical studies of hydroxyanthraquinone derivatives from the endophytic fungus Coniothyrium sp
Chirality, 2013Co-Authors: Peng Sun, Attila Mándi, Tibor Kurtán, Siegfried Draeger, Barbara Schulz, Juan Huo, Sandor Antus, Hua Tang, Hidayat Hussain, Karsten KrohnAbstract:Four known hydroxyanthraquinones (1-4) together with four new derivatives having a tetralone moiety, namely coniothyrinones A-D (5-8), were isolated from the culture of Coniothyrium sp., an endophytic fungus isolated from Salsola oppostifolia from Gomera in the Canary Islands. The structures of the new compounds were elucidated by detailed spectroscopic analysis and comparison with reported data. The absolute configurations of coniothyrinones A (5), B (6), and D (8) were determined by TDDFT calculations of CD spectra, allowing the determination of the absolute configuration of coniothyrinone C (7) as well. Coniothyrinones A (5), B (6), and D (8) could be used as ECD reference compounds in the determination of absolute configuration for related tetralone derivatives. This is the first report of anthraquinones and derivatives from an isolate of the genus Coniothyrium sp. These compounds showed inhibitory effects against the fungus Microbotryum violaceum, the alga Chlorella fusca, and the bacteria Escherichia coli and Bacillus megaterium.
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bioactive nitronaphthalenes from an endophytic fungus Coniothyrium sp and their chemical synthesis
European Journal of Organic Chemistry, 2008Co-Authors: Karsten Krohn, Siegfried Draeger, Simeon F Kouam, Stephan Cludiusbrandt, Barbara SchulzAbstract:Four natural nitro metabolites, 1-hydroxy-5-methoxy-2-nitronaphthalene (2), 1,5-dimethoxy-4-nitronaphthalene (3), 1-hydroxy-5-methoxy-2,4-dinitronaphthalene (4), and 1,5-dimethoxy-4,8-dinitronaphthalene (5), known from chemical synthesis but new as natural products, were isolated together with two known compounds, 1-hydroxy-5-methoxynaphthalene (1) and ergosterol (6) from an endophytic fungus, Coniothyrium sp. The structures of 1–6 were determined by spectroscopic methods including 1D and 2D NMR experiments and by mass spectrometric measurements. The structures of 1–4 were confirmed by chemical synthesis. The nitronaphthols showed considerable antibacterial, antifungal, and antialgal properties.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
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massarilactones e g new metabolites from the endophytic fungus Coniothyrium sp associated with the plant artimisia maritima
Chirality, 2007Co-Authors: Karsten Krohn, Ulrich Florke, Siegfried Draeger, Barbara Schulz, Sandor Antus, Hidayat Hussain, Gennaro Pescitelli, Piero Salvadori, Tibor KurtánAbstract:Three new massarilactones E-G (1–3) and the massarilactone acetonide (4) were isolated from the ethyl acetate extract of the endophytic fungus Coniothyrium sp., associated with the plant Artimisia maritima. Their structures were determined by analysis of the 1D and 2D NMR and mass spectroscopic data. The structure of massarilactones E (1) was confirmed by X-ray diffraction analysis, and its absolute configuration determined by the solid-state CD/TDDFT method. Chirality, 2007. © 2007 Wiley-Liss, Inc.
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new massarilactones massarigenin e and coniothyrenol isolated from the endophytic fungus Coniothyrium sp from carpobrotus edulis
European Journal of Organic Chemistry, 2007Co-Authors: Ines Kock, Karsten Krohn, Siegfried Draeger, Barbara Schulz, Hans Egold, Joachim RheinheimerAbstract:New massarilactones C (3) and D (4), massarigenin E (5), and coniothyrenol (6) were isolated from Coniothyrium sp. together with the known graphislactone A (1) and massarilactone A (2). The relative configuration of coniothyrenol (6) with an unprecedented benzo[a]xanthene skeleton and ten chirality centers was determined by 1D- and 2D-NMR spectroscopy.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
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biologically active metabolites from fungi 10 generation of the palmarumycin spiroacetal framework by oxidative cyclization of an open chain metabolite from Coniothyrium palmarum
Liebigs Annalen, 1997Co-Authors: Karsten Krohn, Karsten Beckmann, Hansjurgen Aust, Siegfried Draeger, Barbara Schulz, Stefan Busemann, Gerhard BringmannAbstract:The first “open chain” representative of the palmarumycins, the biaryl ether 1, was isolated from Coniothyrium palmarum. Phenol oxidation of 1 with silver oxide as a model for a biosynthetic step yielded 4 with the usual spiroacetal structure of the palmarumycins. The absolute (S)-configuration of 4 (and thus of 1) was determined by quantumchemical CD calculations.
Michael J Wingfield - One of the best experts on this subject based on the ideXlab platform.
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high population diversity and increasing importance of the eucalyptus stem canker pathogen teratosphaeria zuluensis in south china
Australasian Plant Pathology, 2011Co-Authors: Shuaifei Chen, Michael J Wingfield, Jolanda Roux, Irene Barnes, Donald Chungu, Yao Jian Xie, Xudong ZhouAbstract:Coniothyrium stem canker, caused by Teratosphaeria zuluensis, is one of the most important diseases of plantation-grown Eucalyptus trees in tropical and sub-tropical areas of the world. Previous research on the population structure of T. zuluensis in China, Malawi and South Africa has suggested that T. zuluensis in these countries had independent origins, with the highest genetic diversity found in a population from South China. In this study, the genetic diversity of three T. zuluensis populations from different regions in South China was determined using ten microsatellite markers. Results showed that more than one genotype of T. zuluensis can occur on a single tree in all three populations and that a moderate to high genetic diversity exists within the populations. Population differentiation was evident between populations, and in one population there was evidence for a low level of genetic recombination. Comparisons among the three populations of T. zuluensis from South China suggest that they originated independently of each other.
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multi gene phylogenies and phenotypic characters distinguish two species within the colletogloeopsis zuluensis complex associated with eucalyptus stem cankers
Studies in Mycology, 2006Co-Authors: Marianoel Cortinas, Brenda D Wingfield, Pedro W. Crous, Michael J WingfieldAbstract:Colletogloeopsis zuluensis, previously known as Coniothyrium zuluense, causes a serious stem canker disease on Eucalyptus spp. grown as non-natives in many tropical and sub-tropical countries. This stem canker disease was first reported from South Africa and it has subsequently been found on various species and hybrids of Eucalyptus in other African countries as well as in countries of South America and South-East Asia. In previous studies, phylogenetic analyses based on DNA sequence data of the ITS region suggested that all material of C. zuluensis was monophyletic. However, the occurrence of the fungus in a greater number of countries, and analyses of DNA sequences with additional isolates has challenged the notion that a single species is involved with Coniothyrium canker. The aim of this study was to consider the phylogenetic relationships amongst C. zuluensis isolates from all available locations and to support these analyses with phenotypic and morphological comparisons. Individual and combined phylogenies were constructed using DNA sequences from the ITS region, exons 3 through 6 of the β-tubulin gene, the intron of the translation elongation factor 1-α gene, and a partial sequence of the mitochondrial ATPase 6 gene. Both phylogenetic data and morphological characteristics showed clearly that isolates of C. zuluensis represent at least two taxa. One of these is C. zuluensis as it was originally described from South Africa, and we provide an epitype for it. The second species occurs in Argentina and Uruguay, and is newly described as C. gauchensis. Both fungi are serious pathogens resulting in identical symptoms. Recognising them as different species has important quarantine consequences.
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first record of colletogloeopsis zuluense comb nov causing a stem canker of eucalyptus in china
Fungal Biology, 2006Co-Authors: Marianoel Cortinas, Brenda D Wingfield, P.w. Crous, T Burgess, B Dell, Michael J WingfieldAbstract:Coniothyrium zuluense causes a serious canker disease of Eucalyptus in various parts of the world. Very little is known regarding the taxonomy of this asexual fungus, which was provided with a name based solely on morphological characteristics. In this study we consider the phylogenetic position of C. zuluense using DNA-based techniques. Distance analysis using 18S and ITS regions revealed extensive sequence divergence relative to the type species of Coniothyrium, C. palmarum and species of ParaConiothyrium. Coniothyrium zuluense was shown to be an anamorph species of Mycosphaerella, a genus that includes a wide range of Eucalyptus leaf and stem pathogens. Within Mycosphaerella it clustered with taxa having pigmented, verruculose, aseptate conidia that proliferate percurrently and sympodially from pigmented conidiogenous cells arranged in conidiomata that vary from being pycnidial to acervular. The genus Colletogloeopsis is emended to include species with pycnidial conidiomata, and the new combination Colletogloeopsis zuluense is proposed. This is also the first report of the pathogen from China where it is associated with stem cankers on Eucalyptus urophylla.
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Characterisation of the Coniothyrium stem canker pathogen on Eucalyptus camaldulensis in Ethiopia
Australasian Plant Pathology, 2005Co-Authors: Alemu Gezahgne, Marianoel Cortinas, Michael J Wingfield, Jolanda RouxAbstract:During a survey ofEucalyptus diseases in Ethiopia, a serious stem canker disease was discovered on E. camaldulensis trees at several localities in the south and south-western parts of the country. The disease was characterise d by the presence of discrete necrotic lesions, stem cankers, cracking of stems, production of kino pockets in the wood, as well as malformation of stems. These symptoms are similar to those caused byConiothyrium zuluense in South Africa. This study identified the causal agent of the disease in Ethiopia by sequencing the ITS regions of the rRNA operon for arepresentative set of isolates. Sequences for the Ethiopian isolates were compared with those from authenticated isolates collected in South Africa, Thailand and Mexico, as well as withConiothyrium-like isolates collected from diseasedEucalyptus trees in Uganda. Pathogenicity trials were also conducted in the greenhouse to determine the virulence of Ethiopian isolates. Based on comparisons of sequence data, the pathogen causing the stem canker disease in Ethiopia was identified as C. zuluense. Isolates from Ethiopia, however, formed their own sub-clade, reflecting geographic isolation of the pathogen. Results, furthermore, also show thatC. zuluense does not reside with otherConiothyrium spp., but rather within the genusMycosphaerella. Small lesions were obtained from inoculatedEucalyptus trees, proving that the fungus is the cause of disease in Ethiopia. This study represents the first confirmed report ofC. zuluense and the disease caused by it in Ethiopia and Uganda. It also shows that C. zuluense is closely related to species ofMycosphaerella and not otherConiothyrium spp. and that it will require a name change in future.
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First record of the Eucalyptus stem canker pathogen, Coniothyrium zuluense from Hawaii.
Australasian Plant Pathology, 2004Co-Authors: Marianoel Cortinas, Brenda D Wingfield, N. Koch, J. Thain, Michael J WingfieldAbstract:A new stem canker disease on Eucalyptus grandis in Hawaii is recorded. Symptoms are similar to those of Coniothyrium canker on Eucalyptus in South Africa. A fungus resembling Coniothyrium zuluense was found on lesions and analysis of ITS sequences confirmed this identification. Coniothyrium canker is a serious disease of Eucalyptus in South Africa and strategies to reduce its impact in Hawaii may be required.