Hypoxylon Species Research Articles

Taxonomy and phylogeny of Hypoxylon zhaotongensis sp. nov. (Hypoxylaceae, Xylariales), a bambusicolous fungus from Yunnan, China

During a survey of bambusicolous fungi in Yunnan Province, southwestern China, several saprobic fungi associated with dead bamboo culms were collected and cursorily identified as species belonging to Xylariales (Sordariomycetes), based on a morphological approach. In this study, a new species, Hypoxylon zhaotongensis, from bamboo was established. In addition, molecular analyses based on multiple gene sequences (ITS, LSU, RPB2, β-tubulin) were carried out to determine the phylogenetic placement of the new isolates. The morphological characteristics show that our new taxon differs from the known Hypoxylon species in having broader asci and ascospores with conspicuously straight germ-slit, which is less than the spore length. Detailed description, photo-plate and a phylogenetic tree showing the taxonomic placement of the new species are provided in this paper.

Three New Species of Hypoxylon (Xylariales, Ascomycota) on a Multigene Phylogeny from Medog in Southwest China.

During a survey of hypoxylaceous fungi in Medog county (Tibet Autonomous Region, China), three new species, including Hypoxylon damuense, Hypoxylon medogense, and Hypoxylon zangii, were described and illustrated based on morphological and multi-gene phylogenetic analyses. Hypoxylon damuense is characterized by its yellow-brown stromatal granules, light-brown to brown ascospores, and frequently indehiscent perispore. Hypoxylon medogense is morphologically and phylogenetically related to H. erythrostroma but differs in having larger ascospores with straight spore-length germ slit and conspicuously coil-like perispore ornamentation. Hypoxylon zangii shows morphological similarities to H. texense but differs in having Amber (47), Fulvous (43) and Sienna (8) KOH-extractable pigments and larger ascospores with straight spore-length germ slit. The multi-gene phylogenetic analyses inferred from the datasets of ITS-RPB2-LSU-TUB2 supported the three new taxa as separate lineages within Hypoxylon. A key to all known Hypoxylon species from China and related species worldwide is provided.

Multi-Gene Phylogeny and Taxonomy of Hypoxylon (Hypoxylaceae, Ascomycota) from China

The Hypoxylon species play an important ecological role in tropical rainforest as wood-decomposers, and some might have benefical effects on their hosts as endophytes. The present work concerns a survey of the genus Hypoxylon from Hainan Tropical Rainforest National Park of China. Four new species: H. wuzhishanense, H. hainanense, H.chrysalidosporum, and H.cyclobalanopsidis, were discovered based on a combination of morphological characteristics and molecular data. Hypoxylon wuzhishanense is characterized by Rust pulvinate stromata, amyloid apical apparatus and brown ascospores, with most of the perispore being indehiscent in 10% KOH. Hypoxylon hainanense has effused–pulvinate and Violet stromata, amyloid apical apparatus, light-brown to brown ascospores with straight germ slit and dehiscent perispore. Hypoxylonchrysalidosporum is distinguished by glomerate to pulvinate stromata, highly reduced or absent inamyloid apical apparatus, and light-brown to brown ascospores with very conspicuous coil-like ornamentation. Hypoxyloncyclobalanopsidis has Livid Purple pulvinate stromata, highly reduced amyloid apical apparatus, faint bluing, brown ascospores and dehiscent perispore, and it grows on dead branches of Cyclobalanopsis. Detailed descriptions, illustrations, and contrasts with morphologically similar species are provided. Phylogenetic analyses inferred from ITS, RPB2, LSU, and β-tubulin sequences confirmed that the four new species are distinct within the genus Hypoxylon.

Resolution of the Hypoxylon fuscum Complex (Hypoxylaceae, Xylariales) and Discovery and Biological Characterization of Two of Its Prominent Secondary Metabolites.

Hypoxylon, a large, cosmopolitan genus of Ascomycota is in the focus of our current poly-thetic taxonomic studies, and served as an excellent source for bioactive secondary metabolites at the same time. The present work concerns a survey of the Hypoxylon fuscum species complex based on specimens from Iran and Europe by morphological studies and high performance liquid chromatography coupled to mass spectrometry and diode array detection (HPLC-MS-DAD). Apart from known chemotaxonomic markers like binaphthalene tetrol (BNT) and daldinin F, two unprece-dented molecules were detected and subsequently isolated to purity by semi preparative HPLC. Their structures were established by nuclear-magnetic resonance (NMR) spectroscopy as 3′-malonyl-daldinin F (6) and pseudofuscochalasin A (4). The new daldinin derivative 6 showed weak cytotoxicity towards mammalian cells but bactericidal activity. The new cytochalasin 4 was compared to cytochalasin C in an actin disruption assay using fluorescence microscopy of human osteo-sarcoma U2OS cells, revealing comparable activity towards F-actin but being irreversible compared to cytochalasin C. Concurrently, a multilocus molecular phylogeny based on ribosomal and proteinogenic nucleotide sequences of Hypoxylon species resulted in a well-supported clade for H. fuscum and its allies. From a comparison of morphological, chemotaxonomic and phylogenetic evidence, we introduce the new species H. eurasiaticum and H. pseudofuscum.

Antifungal and antioomycete activities and modes of action of isobenzofuranones isolated from the endophytic fungus Hypoxylon anthochroum strain Gseg1

Hypoxylon species are distributed worldwide and have been isolated from different habitats. The endophyte Hypoxylon anthochroum strain Gseg1 was isolated from healthy leaves of Gliricidia sepium. A chemical study of the culture medium and mycelium organic extracts of the endophytic fungus H. anthochroum Gseg1 led to the isolation of three known isobenzofuranones, 7-hydroxy-4,6-dimethyl-3H-isobenzofuran-1-one, 1, 7-methoxy-4,6-dimethyl-3H-isobenzofuran-1-one, 2, 6-formyl-4-methyl-7-methoxy-3H-isobenzofuran-1-one, 3, and one compound was isolated for the first time as a natural product, 7-methoxy-4-methyl-3H-isobenzofuran-1-one, 4. In addition, the chemical synthesis of 1 and 2, and a derivative, 7-methoxy-6-methyl-3H-isobenzofuran-1-one, 5, was performed. The isobenzofuranones showed antifungal and antioomycete activities. Compounds 1–5 inhibited the growth of Fusarium oxysporum, Alternaria alternata, Pythium aphanidermatum, and Phytophthora capsici, in addition, 1, 2 and 5 interrupted the respiration and caused electrolyte leakage due to cell membrane damage. Compound 2 was the most active, inhibiting the growth of the four microorganisms, affecting the respiration and increasing the relative conductivity due to electrolyte leakage. Compounds 1–4 also induce morphological changes in the plant pathogens' mycelia and hyphae. These compounds could be useful for the control of plant pathogenic fungi and oomycetes of agricultural relevance.

El género Hypoxylon (Xylariales, Ascomycota) en el bosque tropical caducifolio de cuatro Áreas Naturales Protegidas de México.

Antecedentes y Objetivos: El género Hypoxylon (Hypoxylaceae) tiene peritecios embebidos en un estroma oscuro o de colores brillantes, efuso-aplanado, efuso-pulvinado o glomerulado, ascas cilíndricas con poro apical amiloide, ascosporas elipsoides, equiláteras o inequiláteras, marrón claro a marrón oscuro, línea germinal recta o sigmoide y perisporio generalmente dehiscente con KOH al 10%. El género tiene una distribución mundial; se han descrito 115 especies con mayor diversidad en las regiones tropicales. En México se tenían registrados 36 taxones, de los cuales 20 se citan del bosque tropical caducifolio. El objetivo del presente estudio es ampliar la distribución conocida y describir las especies de Hypoxylon que crecen en el bosque tropical caducifolio de cuatro Áreas Naturales Protegidas (ANPs) de México.Métodos: Se realizaron seis exploraciones en las siguientes ANPs de México: Reserva de la Biosfera Chamela-Cuixmala (Jalisco), Reserva de la Biosfera Isla Cozumel (Quintana Roo), Reserva de la Biosfera Sierra de Álamos-Río Cuchujaqui (Sonora) y Reserva de la Biosfera El Cielo (Tamaulipas). Los ejemplares recolectados fueron estudiados, descritos y determinados de acuerdo con las técnicas tradicionales en micología. El material está depositado en el herbario ENCB.Resultados clave: Se determinaron 11 especies de Hypoxylon, y se describe por primera vez para México Hypoxylon jaklitschii de Jalisco, Quintana Roo y Tamaulipas. Además, se amplía la distribución conocida de H. anthochroum, H. cinnabarinum, H. erythrostroma, H. haematostroma, H. investiens, H. lividipigmentum, H. perforatum, H. rickii e Hypoxylon subgilvum a otros estados.Conclusiones: Hypoxylon está bien representado en México, siendo uno de los mejor estudiados del orden Xylariales. Hypoxylon cinnabarinum, H. haematostroma e H. lenormandii se encontraron en todas las ANPs del presente estudio. La Reserva de la Biosfera el Cielo es el ANP con mayor número de especies con nueve.

Discovery of a new species of the Hypoxylon rubiginosum complex from Iran and antagonistic activities of Hypoxylon spp. against the Ash Dieback pathogen, Hymenoscyphus fraxineus, in dual culture.

During a survey of xylarialean fungi in Northern Iran, several specimens that showed affinities to the Hypoxylon rubiginosum complex were collected and cultured. A comparison of their morphological characters, combined with a chemotaxonomic study based on high performance liquid chromatography, coupled with diode array detection and mass spectrometry (HPLC-DAD/MS) and a multi-locus phylogeny based on ITS, LSU, rbp2 and tub2 DNA sequences, revealed a new species here described as Hypoxylon guilanense. In addition, Hypoxylon rubiginosumsensu stricto was also encountered. Concurrently, an endophytic isolate of the latter species showed strong antagonistic activities against the Ash Dieback pathogen, Hymenoscyphus fraxineus, in a dual culture assay in our laboratory. Therefore, we decided to test the new Iranian fungi for antagonistic activities against the pathogen, along with several cultures of other Hypoxylon species that are related to H. rubiginosum. Our results suggest that the antagonistic effects of Hypoxylon spp. against Hym. fraxineus are widespread and that they are due to the production of antifungal phomopsidin derivatives in the presence of the pathogen.

Observations on Texas hypoxylons, including two new Hypoxylon species and widespread environmental isolates of the H. croceum complex identified by a polyphasic approach

ABSTRACTTwo new species and a new combination of Hypoxylon from Texas were identified and described based on morphological, multigene phylogenetic (ITS [nuc rDNA internal transcribed spacer region ITS1-5.8S-ITS2], 28S [5′ 1200 bp of nuc 28S rDNA], RPB2 [partial second largest subunit of the DNA-directed RNA polymerase II], TUB2 [partial β-tubulin]), and chemotaxonomic data. Hypoxylon olivaceopigmentum is characterized by its pulvinate to glomerate stromata, olivaceous KOH-extractable pigments, equilateral ascospores, and indehiscent perispore. Hypoxylon texense can be distinguished from morphologically similar species by its rust to dark brick KOH-extractable pigments and the high-performance liquid chromatography (HPLC) profile of its stromatal secondary metabolites. Hypoxylon hinnuleum is proposed as the sexual morph of Nodulisporium hinnuleum, featuring dark vinaceous glomerate stromata with dark brick KOH-extractable pigments composed of cohaerin-type azaphilones and smooth equilateral ascospores with indehiscent perispore. Based on these diagnostic characters, H. hinnuleum forms a complex with H. croceum and H. minicroceum. More than 50 ITS sequences with high identity originating from North American and East Asian environmental isolates formed a well-supported clade with the type of N. hinnuleum, demonstrating the widespread distribution of the species complex. In addition, updated descriptions and comprehensive illustrations with detailed information on the diagnostic features of H. fendleri and H. perforatum are provided. The multilocus phylogenetic reconstruction of Hypoxylon supported the status of the new species and broadened the knowledge about intergeneric relationships.

Two Hypoxylon species from Yunnan Province based on morphological and molecular characters

Two specimens of Hypoxylon were collected from Yunnan, southwestern China. Hypoxylon baihualingense, an undescribed species of Hypoxylon (Xylariales, Hypoxylaceae), is described and illustrated as a new species based on a combination of morphological and phylogenetic (ITS and β-tubulin sequences) data. The new species is characterized by its glomerate to pulvinate stromata with ostiolar discs and asci lacking an apical apparatus. The differences between the new species and some morphologically similar Hypoxylon species are discussed. Hypoxylon polyporoideum is reported as a new record from China.

New records of Hypoxylon (Ascomycota, Hypoxylaceae) for the Argentine Yungas

Hypoxylon aeruginosum var. aeruginosum , H. fendleri and H. undulatum collected in the subtropical montane forest from northwest of Argentina are reported for first time for Southern Cone. We describe and analyze their teleomorph and anamorph, provide photographs and drawing of the most relevant structures. Moreover, a key to Hypoxylon species so far known from Argentina is given.

New species and reports of Hypoxylon from Argentina recognized by a polyphasic approach

A preliminary account of Hypoxylon species (Xylariaceae) from the hitherto widely unexplored “Yungas” mountain forests of Northwest Argentina is presented. Two new species are described based on extensive morphological, molecular (ITS region of rDNA, partial β-tubulin gene) and chemotaxonomic data. Hypoxylon spegazzinianum is close to H. erythrostroma, but differs by larger ascospores and a virgariella-like asexual morph. Hypoxylon calileguense resembles H. subgilvum when growing on wood, but can be distinguished by larger ascospores and a fawn to brick stromatal surface colour. Stromata found on bark have affinities to H. pelliculosum, but differ in their stromatal surface colour and conspicuous amyloid apical apparatus. In addition, nine taxa of Hypoxylon are reported for Argentina for the first time, and some details on their asexual state and stromatal secondary metabolites are reported. An updated dichotomous key for Hypoxylon species from Argentina is provided.

Hypoxylon (Xylariaceae, Ascomycota) from Western Paraná, Brazil

Hypoxylon is one of the most specious genera in Xylariaceae, whose species are saprobes or facultative parasites. In a survey of the Hypoxylon species from Parque Estadual de Sao Camilo, municipality of the Palotina, West region of Parana State (24°18′00″–24°19′30″S and 53°53′30″–53°55′30″W). Twelve taxa were found: H. anthochroum, H. griseobrunneum, H. lenormandii, H. monticulosum, Hypoxylon peleae, H. cf. pilgerianum, H. rickii, H rubigineoareolatum, H. rubiginosum, H. subgilvum, H. subrutilum, and Hypoxylon vinaceobrunneum. Among these, H. vinaceobrunneum is proposed as new species, based on the following characters: surface effused-pulvinate, brown vinaceous; without apparent KOH-extractable pigments or with dilute grayish sepia; ostioles slightly papillate; ascospores light brown to brown, 7–10 × 3–3.5 µm, with slightly germ slit shorter than the spore-length. H. peleae is new to South America, whereas H. griseobrunneum is new to Brazil, and all the remaining taxa are newly reported from the State of Parana or Southern Brazil. Key for the identification, morphological descriptions, and illustrations are presented for all species.

New Hypoxylon species from Martinique and new evidence on the molecular phylogeny of Hypoxylon based on ITS rDNA and β-tubulin data

Three new species of Hypoxylon (Xylariaceae) collected from Martinique in the French Caribbean are recognised by new combinations of morphological characters. Their status as undescribed taxa was supported by secondary metabolite profiling based on High performance liquid chromatography with diode array and mass spectrometric detection (HPLC/DAD-MS) as well as by comparison of ITS and partial s-tubulin DNA sequences with related taxa. In the course of this study, the teleomorph of Nodulisporium griseobrunneum was found, and this species could be transferred to Hypoxylon. Moreover, several names in Hypoxylon are epitypified by selecting recently collected specimens from the same geographic areas as the holotypes came from. Despite the fact that our study used the hitherto most extensive taxon sampling, the phylogenetic analyses inferred from ITS and s-tubulin sequences remain contradictory to each other, and neither genealogy was found fully in agreement with phenotype-derived traits. We conclude that the right gene (or multi-gene genealogies) to reflect the phylogeny and evolution of Hypoxylon still remains to be found. For the time being, we recommend that the application of polyphasic taxonomic concepts should be continued in taxonomic studies of Hypoxylon.

Fungi in Thailand: a case study of the efficacy of an ITS barcode for automatically identifying species within the Annulohypoxylon and Hypoxylon genera.

Thailand, a part of the Indo-Burma biodiversity hotspot, has many endemic animals and plants. Some of its fungal species are difficult to recognize and separate, complicating assessments of biodiversity. We assessed species diversity within the fungal genera Annulohypoxylon and Hypoxylon, which produce biologically active and potentially therapeutic compounds, by applying classical taxonomic methods to 552 teleomorphs collected from across Thailand. Using probability of correct identification (PCI), we also assessed the efficacy of automated species identification with a fungal barcode marker, ITS, in the model system of Annulohypoxylon and Hypoxylon. The 552 teleomorphs yielded 137 ITS sequences; in addition, we examined 128 GenBank ITS sequences, to assess biases in evaluating a DNA barcode with GenBank data. The use of multiple sequence alignment in a barcode database like BOLD raises some concerns about non-protein barcode markers like ITS, so we also compared species identification using different alignment methods. Our results suggest the following. (1) Multiple sequence alignment of ITS sequences is competitive with pairwise alignment when identifying species, so BOLD should be able to preserve its present bioinformatics workflow for species identification for ITS, and possibly therefore with at least some other non-protein barcode markers. (2) Automated species identification is insensitive to a specific choice of evolutionary distance, contributing to resolution of a current debate in DNA barcoding. (3) Statistical methods are available to address, at least partially, the possibility of expert misidentification of species. Phylogenetic trees discovered a cryptic species and strongly supported monophyletic clades for many Annulohypoxylon and Hypoxylon species, suggesting that ITS can contribute usefully to a barcode for these fungi. The PCIs here, derived solely from ITS, suggest that a fungal barcode will require secondary markers in Annulohypoxylon and Hypoxylon, however. The URL http://tinyurl.com/spouge-barcode contains computer programs and other supplementary material relevant to this article.

Lepraric acid derivatives as chemotaxonomic markers in Hypoxylon aeruginosum, Chlorostroma subcubisporum and C. cyaninum, sp. nov.

Hypoxylon aeruginosum ( Xylariaceae), an infrequently encountered predominantly tropical pyrenomycete, of which two varieties are known to science, is characterised by having a cyan blue stromatal surface or subsurface. In the course of our ongoing chemotaxonomic evaluation of the Xylariaceae, specific profiles of H. aeruginosum were observed by high performance liquid chromatography, coupled with diode array detection and mass spectrometry ( hplc-DAD/MS). By comparison with an authentic standard, lepraric acid and several yet unidentified metabolites with similar hplc-DAD/MS characteristics were detected in the stromata of the type material and other specimens of this species. Interestingly, lepraric acid was hitherto only known from lichenised ascomycetes. Hypoxylon aeruginosum, which is here reported first from Africa and Asia, contained none of the metabolites that were previously detected in other Xylariaceae, except for stromata growing hyperparasitically on other Hypoxylon species. A different lepraric acid derivative was also detected in the type specimen of Chlorostroma subcubisporum, which differs from H. aeruginosum by having a green stromatal surface, cuboid ascospores, and in lacking an amyloid ascal apical apparatus. A second species of Chlorostroma, which showed essentially the same metabolite profile as H. aeruginosum, is described from Thailand. We conclude that Chlorostroma and H. aeruginosum are closely related. However, no taxonomic conclusions are drawn from these findings because no cultures have so far become available to study their anamorphic morphology, their secondary metabolites in culture, and their molecular phylogeny. Taxonomic novelty: Chlorostroma cyaninum Læssøe, Srikitikulchai & J. Fournier, sp. nov.

New Hypoxylon and Nemania species from Costa Rica and Taiwan

Six xylariaceous fungi, including two Hypoxylon taxa and four Nemania taxa, are described as new. They were collected from either Costa Rica or Taiwan. Two of the Nemania species—N. flavitextura and N. primolutea—were cultured and typical Geniculosporium anamorphs were produced.

New Hypoxylon and Nemania species from Costa Rica and Taiwan

Six xylariaceous fungi, including two Hypoxylon taxa and four Nemania taxa, are described as new. They were collected from either Costa Rica or Taiwan. Two of the Nemania species--N. flavitextura and N. primolutea--were cultured and typical Geniculosporium anamorphs were produced.

Hypomiltin, a novel azaphilone from Hypoxylon hypomiltum, and chemotypes in Hypoxylon sect. Hypoxylon as inferred from analytical HPLC profiling

A novel azaphilone named hypomiltin was isolated by preparative reversed phase HPLC from the stromatal extract of the xylariaceous ascomycete Hypoxylon hypomiltum. Its chemical structure was determined by mass spectrometry and 2D nuclear magnetic resonance spectroscopy. Analytical HPLC profiling of stromatal crude extracts, using UV/visual (diode array) and mass spectrometric detection based on electrospray ionisation, revealed the presence of hypomiltin also in Hypoxylon intermedium, H. perforatum, H. trugodes, and Pulveria porrecta. In contrast, this compound was found neither in type material of H. hypomiltum var. lavandulocinereum nor in several further Hypoxylon species. Despite being chemically related to mitorubrin, hypomiltin never co-occurred with the latter compound and its derivatives. Characteristic secondary metabolite profiles of several further Hypoxylon species are correlated with the colours of their taxonomically significant KOH-extractable pigments. These species are divided into chemotypes, based on analytical HPLC data. The results point toward an extraordinary diversity of secondary metabolites in Hypoxylon.

Hypoxylon species on beech and other broadleaves

Fungi in the genus Hypoxylon cause wood decay and most of them are saprophytes on dead wood or parasites of weakness. The following species in this genus were identified in this study performed at several localities in Serbia and Montenegro: H. deustum, H. fragiforme, H. nummularium, H. multiforme, H. rubiginosum and H. fuscum. Among them the most significant species is H. deustum, the fungus causing root and butt rot of standing beech trees. It was recorded from all coppice and high forests of beech. This paper presents the morphological characteristics of the recorded fungi their range, plant hosts and significance.

New Hypoxylon Species and Notes on Some Names Associated with or Related to Hypoxylon

These new species of Hypoxylon are described: H. elevatidiscus, H. squamulosum, H. subalbum and H. vinosopulvinatum. A referenced list of all Hypoxylon species known to us described since 1996 is given and a key presented. Names associated with Hypoxylon that were not given in the Ju and Rogers monograph are annotated and diagnostic corrections of taxa discussed in that monograph are given.