Esteban Benjamin Sir

Lenormandins A—G, new azaphilones from Hypoxylon lenormandii and Hypoxylon jaklitschii sp. nov., recognised by chemotaxonomic data

Seven new azaphilone pigments named lenormandins A–G were isolated from stromata (fruiting bodies) of the xylariaceous fungus, Hypoxylon lenormandii using preparative High Performance Liquid Chromatography (HPLC) and their structures were elucidated by NMR spectroscopy, high resolution mass spectrometry and other spectral methods. Their occurrence in herbarium specimens (including various type materials collected in the 19th and early 20th century) and several fresh collections was studied by analytical HPLC with diode array and mass spectrometric detection (HPLC-DAD/MS), revealing that this group of pigments is specific for Hypoxylon lenormandii from various geographic regions and otherwise only occurs in closely related taxa, i.e. H. sublenormandii and an undescribed fungus from Sri Lanka, for which we propose the name H. jaklitschii. The status of the new species was established by using molecular phylogenetic data based on ITS and partial beta-tubulin sequences, and by detailed morphological studies.

Resurrection and emendation of the Hypoxylaceae, recognised from a multigene phylogeny of the Xylariales

A multigene phylogeny was constructed, including a significant number of representative species of the main lineages in the Xylariaceae and four DNA loci the internal transcribed spacer region (ITS), the large subunit (LSU) of the nuclear rDNA, the second largest subunit of the RNA polymerase II (RPB2), and beta-tubulin (TUB2). Specimens were selected based on more than a decade of intensive morphological and chemotaxonomic work, and cautious taxon sampling was performed to cover the major lineages of the Xylariaceae; however, with emphasis on hypoxyloid species. The comprehensive phylogenetic analysis revealed a clear-cut segregation of the Xylariaceae into several major clades, which was well in accordance with previously established morphological and chemotaxonomic concepts. One of these clades contained Annulohypoxylon, Hypoxylon, Daldinia, and other related genera that have stromatal pigments and a nodulisporium-like anamorph. They are accommodated in the family Hypoxylaceae, which is resurrected and emended. Representatives of genera with a nodulisporium-like anamorph and bipartite stromata, lacking stromatal pigments (i.e. Biscogniauxia, Camillea, and Obolarina) appeared in a clade basal to the xylarioid taxa. As they clustered with Graphostroma platystomum, they are accommodated in the Graphostromataceae. The new genus Jackrogersella with J. multiformis as type species is segregated from Annulohypoxylon. The genus Pyrenopolyporus is resurrected for Hypoxylon polyporus and allied species. The genus Daldinia and its allies Entonaema, Rhopalostroma, Ruwenzoria, and Thamnomyces appeared in two separate subclades, which may warrant further splitting of Daldinia in the future, and even Hypoxylon was divided in several clades. However, more species of these genera need to be studied before a conclusive taxonomic rearrangement can be envisaged. Epitypes were designated for several important species in which living cultures and molecular data are available, in order to stabilise the taxonomy of the Xylariales.

Towards a natural classification and backbone tree for Graphostromataceae , Hypoxylaceae , Lopadostomataceae and Xylariaceae

Species and generic recognition in the order Xylariales has been uncertain due to lack of molecular data from authentic cultures, as well as overlapping morphological characteristics. In this study, we revise the families Graphostromataceae, Hypoxylaceae, Lopadostomataceae and Xylariaceae in Xylariales. Our study is based on DNA sequence data derived from living cultures of fresh isolates, data from GenBank and morphological observation of type and worldwide herbarium specimens. We also collected new specimens from Germany, Italy and Thailand. Combined analyses of ITS, LSU, RPB2 and β-tubulin sequence data were used to reconstruct the molecular phylogeny of the above families. Generic and familiar boundaries between these families are revised and presented in an updated combined phylogenetic tree. We accept six genera in Graphostromataceae, 19 genera in Hypoxylaceae, four in Lopadostomataceae and 37 genera in Xylariaceae. Five genera previously treated in Xylariaceae are placed in Amphisphaeriales genera incertae sedis and seven genera are placed in Xylariales genera incertae sedis. Two genera are placed in Sordariomycetes genera incertae sedis, while four genera are placed as Xylariomycetidae genera incertae sedis. Three genera are considered as doubtful. Barrmaelia and Cannonia, presently included in Xylariaceae are transferred to Diatrypaceae and Coniochaetales respectively, based on their morphology and phylogeny. Areolospora and Myconeesia are excluded from Xylariaceae and synonymized with Phaeosporis and Anthostomella respectively. Updated descriptions and illustrations are provided for all taxa with notes provided on each genus. Excluded and doubtful genera are listed with notes on their taxonomy and phylogeny. Taxonomic keys are provided for all revised families with morphological details for genera within the families.

Phylogenetic and chemotaxonomic resolution of the genus Annulohypoxylon (Xylariaceae) including four new species

This study deals with an extensive evaluation focusing on phylogenetic and chemotaxonomic infrageneric relationships of the genus Annulohypoxylon (Xylariaceae, Ascomycota), whose species are ubiquitously associated with seed plants as endophytes and saprotrophs in all forested areas of the world. Using evidence from phylogenetic, chemotaxonomic and morphological data, various varieties within the genus are raised to species level, leading to the new combinations for A. areolatum (≡ A. bovei var. microsporum), A. macrosporum (≡ A. leptascum var. macrosporum), and A. microdiscum (≡ A. moriforme var. microdiscum). Annulohypoxylon substygium nom. nov. is applied for A. stygium var. annulatum and the four new tropical and subtropical species A. massivum, A. violaceopigmentum, A. viridistratum and A. yungensis are introduced. Furthermore, A. leucadendri is excluded from the genus as its morphological characters disagree with the generic concept, the recently erected A. palmicola is synonymized with A. leptascum and A. austrobahiense has been reassigned to the genus Hypoxylon. In addition, the key taxa A. annulatum and A. truncatum have been reinvestigated and epitypes have been defined. For the first time, a dichotomous key to the genus is provided. A phylogenetic β-tubulin tree in conjunction with stromatal HPLC profiles clearly shows that Annulohypoxylon comprises two distinct lineages. The A. cohaerens/multiforme group might eventually warrant segregation into a new genus as further molecular data become available.

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.

Discovery of new mitorubrin derivatives from Hypoxylon fulvo-sulphureum sp. nov. (Ascomycota, Xylariales)

A specimen of the Hypoxylon rubiginosum complex featuring unusual bicoloured stromata was collected in northern Thailand and examined by means of classical morphological methodology, complemented by studies of its secondary metabolites using high performance liquid chromatography coupled with diode array and electrospray mass spectrometric detection (HPLC-DAD/MS), and molecular phylogenetic analysis of its ITS and partial beta-tubulin DNA sequences. In addition, the ultrastructure of its ascospores was examined by SEM. The chemotaxonomic studies revealed the presence of two putatively unknown, apparently specific azaphilone pigments in the stromata. These metabolites were consequently isolated to purity by preparative HPLC and identified by means of nuclear magnetic resonance spectroscopy and high resolution mass spectrometry as the novel natural products, (+)-6″-hydroxymitorubrinol acetate (1) and (+)-6″-hydroxymitorubrinol (3).