Otto Miettinen

A phylogenetic overview of the antrodia clade (Basidiomycota, Polyporales)

Phylogenetic relationships among members of the antrodia clade were investigated with molecular data from two nuclear ribosomal DNA regions, LSU and ITS. A total of 123 species representing 26 genera producing a brown rot were included in the present study. Three DNA datasets (combined LSU-ITS dataset, LSU dataset, ITS dataset) comprising sequences of 449 isolates were evaluated with three different phylogenetic analyses (maximum likelihood, maximum parsimony, Bayesian inference). We present a phylogenetic overview of the five main groups recovered: the fibroporia, laetiporus, postia, laricifomes and core antrodia groups. Not all of the main groups received strong support in the analyses, requiring further research. We were able to identify a number of well supported clades within the main groups.

Comprehensive taxon sampling reveals unaccounted diversity and morphological plasticity in a group of dimitic polypores (Polyporales, Basidiomycota)

The phylogeny of the poroid and hydnoid genera Antrodiella, Junghuhnia, and Steccherinum (Polyporales, Basidiomycota) was studied utilizing sequences of the gene regions ITS, nLSU, mtSSU, atp6, rpb2, and tef1. Altogether 148 taxa, represented by 549 sequences, were included in analyses. Results show that most species of these genera form a well supported clade in the Polyporales, called Steccherinaceae, along with 12 other hydnoid and poroid genera. Within the Steccherinaceae, generic concepts need to be revised: no fewer than 15 new genera are needed to accommodate existing and new species. At least 16 transitions have taken place between poroid and hydnoid hymenophore types within the Steccherinaceae, and similar plasticity can be seen in microscopic characters. Nevertheless, natural genera revealed in the analysis can mostly be characterized morphologically and, with few exceptions, poroid and hydnoid species belong to separate genera. The genus Steccherinum is shown to contain both hydnoid and poroid species. Species of the former Antrodiella belong to at least 10 genera within the Steccherinaceae.

Sidera, a new genus in Hymenochaetales with poroid and hydnoid species

A new genus, Sidera (Hymenochaetales), is described to accommodate the dimitic polypores Skeletocutis lenis and S. vulgaris, the monomitic polypore Ceriporiopsis lowei, and the monomitic, hydnoid Athelopsis lunata. The genus is characterised by white-rot, whitish resupinate fruiting bodies, crystal rosettes on specialised hyphae, and allantoid spores. Cinereomyces (Polyporales) is confirmed to be a good genus including C. lindbladii, separate from Diplomitoporus as defined by its type species D. flavescens and the closely related D. crustulinus. Fabisporus is a taxonomic synonym of Diplomitoporus. Poriodontia subvinosa belongs to the Hymenochaetales.

Obba and Sebipora, new polypore genera related to Cinereomyces and Gelatoporia (Polyporales, Basidiomycota)

Cinereomyces clade is a newly proposed monophyletic group of polypores containing currently four genera and five species, including two promising biopulping fungi, Ceriporiopsis rivulosa and C. subvermispora. The Cinereomyces clade is well-delimited in nrDNA-based phylogenetic analysis, but its position in Polyporales remains unclear. Its closest relative may be found in the core polyporoid clade. Only a few morphological characters are common for all the species in the clade, e.g. CB– and CRB+ hyphae, white fruiting bodies, presence of oil, and middle-sized spores. Culturally, the species are unified by producing simple-septate generative hyhpae in the margin, which produce simple-clamped hyphae backwards. The genus Gelatoporia is the correct place for Ceriporiopsis subvermispora. Two new genera are described in the group: Obba to incorporate C. rivulosa and a new austral species, Obba valdiviana, known from southern Argentina and recorded here also from Tasmania, and Sebipora to accommodate a new species from tropical Asia, S. aquosa. ITS sequences imply that Eurasian Gelatoporia subvermispora may belong to a different species from the North American one. G. subvermispora is recorded as new to Indonesia.

Antrodia hyalina, a new polypore from Russia, and A. leucaena, new to Europe

A new polypore species, Antrodia hyalina, is described from Russia. It is morphologically similar to Antrodia pulvinascens, but differs in having annual, thinner and softer basidiocarps, solid skeletal hyphae, and cylindrical spores. Antrodia leucaena, originally described from China, is reported as new from Finland and Russia on Populus tremula. Antrodia wangii is regarded as a synonym of A. bondartsevae.

What is Antrodia sensu stricto

The polypore genus Antrodia (Polyporales, Basidiomycota) in the strict sense consists of a small number of species grouped around the type species A. serpens in phylogenetic analyses. This distinct clade (Antrodia sensu stricto in our view) contains species of the Antrodia heteromorpha complex, A. macra coll. and Antrodia mappa (formerly Postia mappa). Nuclear rDNA ITS and tef1 data show that the Antrodia heteromorpha species complex includes four species: A. heteromorpha sensu stricto (mostly on gymnosperms, large pores and spores), A. serpens (on angiosperms in Europe, resupinate, smaller pores but large spores), A. favescens (smaller pores and spores, pileate species in North America, formerly known as Trametes sepium), and A. tanakai (a close kin of A. favescens in Eurasia). Antrodia albida is a synonym of A. heteromorpha sensu stricto. We combine A. mappa, A. favescens and A. tanakai in Antrodia and designate neotypes for A. albida and A. heteromorpha, and an epitype for A. serpens. We also compare the morphologically similar but distantly related A. albidoides and A. mellita, and conclude that A. macrospora and A. subalbidoides are synonyms of A. albidoides.

Notes on the Genus Aporpium (Auriculariales, Basidiomycota), with a New Species from Temperate Europe

A new polypore, Aporpium macroporum Niemelä, Spirin & Miettinen, is described on the basis of material from Finland, Poland (Białowieza National Park; type locality), European Russia, Belarus, Estonia, and Latvia. It grows primarily on fallen aspen trees and prefers old forests with abundant coarse woody debris. Aporpium caryae is an American taxon, and its European kin is A. canescens; A. macroporum differs from them in having wider pores, softer consistency, and paler colours. The spores of the new species are wider than in A. canescens, and longer than in A. caryae. The three species can be distinguished by their ribosomal DNA ITS sequences. We briefly discuss the heterobasidioid genera Aporpium, Elmerina and Protomerulius.

Species diversity in the Antrodia crassa group (Polyporales, Basidiomycota)

Antrodia is a polyphyletic genus, comprising brown-rot polypores with annual or short-lived perennial resupinate, dimitic basidiocarps. Here we focus on species that are closely related to Antrodia crassa, and investigate their phylogeny and species delimitation using geographic, ecological, morphological and molecular data (ITS and LSU rDNA, tef1). Phylogenetic analyses distinguished four clades within the monophyletic group of eleven conifer-inhabiting species (five described herein): (1)A. crassa s. str. (boreal Eurasia), Antrodia cincta sp. nova (North America) and Antrodia cretacea sp. nova (holarctic), all three being characterized by inamyloid skeletal hyphae that dissolve quickly in KOH solution; (2) Antrodia ignobilis sp. nova, Antrodia sitchensis and Antrodia sordida from North America, and Antrodia piceata sp. nova (previously considered conspecific with A. sitchensis) from Eurasia, possessing amyloid skeletal hyphae; (3) Antrodia ladiana sp. nova from the southern part of the USA, Antrodia pinea from East Asia, and Antrodia ferox - so far known from subtropical North America, but here reported also from Eurasia. These three species have inamyloid hyphae and narrow basidiospores; (4) the North American Antrodia pini-cubensis, sharing similar morphological characters with A. pinea, forming a separate clade. The habitat data indicate that several species are threatened by intensive forestry.

Molecular phylogeny of Rigidoporus microporus isolates associated with white rot disease of rubber trees (Hevea brasiliensis).

Rigidoporus microporus (Polyporales, Basidiomycota) syn. Rigidoporus lignosus is the most destructive root pathogen of rubber plantations distributed in tropical and sub-tropical regions. Our primary objective was to characterize Nigerian isolates from rubber tree and compare them with other West African, Southeast Asian and American isolates. To characterize the 20 isolates from Nigeria, we used sequence data of the nuclear ribosomal DNA ITS and LSU, β-tubulin and translation elongation factor 1-α (tef1) gene sequences. Altogether, 40 isolates of R. microporus were included in the analyses. Isolates from Africa, Asia and South/Central America formed three distinctive clades corresponding to at least three species. No phylogeographic pattern was detected among R. microporus collected from West and Central African rubber plantations suggesting continuous gene flow among these populations. Our molecular phylogenetic analysis suggests the presence of two distinctive species associated with the white rot disease. Phylogenetic analyses placed R. microporus in the Hymenochaetales in the vicinity of Oxyporus. This is the first study to characterize R. microporus isolates from Nigeria through molecular phylogenetic techniques, and also the first to compare isolates from rubber plantations in Africa and Asia.

Temporal transcriptome analysis of the white-rot fungus Obba rivulosa shows expression of a constitutive set of plant cell wall degradation targeted genes during growth on solid spruce wood

The basidiomycete white-rot fungus Obba rivulosa, a close relative of Gelatoporia (Ceriporiopsis) subvermispora, is an efficient degrader of softwood. The dikaryotic O. rivulosa strain T241i (FBCC949) has been shown to selectively remove lignin from spruce wood prior to depolymerization of plant cell wall polysaccharides, thus possessing potential in biotechnological applications such as pretreatment of wood in pulp and paper industry. In this work, we studied the time-course of the conversion of spruce by the genome-sequenced monokaryotic O. rivulosa strain 3A-2, which is derived from the dikaryon T241i, to get insight into transcriptome level changes during prolonged solid state cultivation. During 8-week cultivation, O. rivulosa expressed a constitutive set of genes encoding putative plant cell wall degrading enzymes. High level of expression of the genes targeted towards all plant cell wall polymers was detected at 2-week time point, after which majority of the genes showed reduced expression. This implicated non-selective degradation of lignin by the O. rivulosa monokaryon and suggests high variation between mono- and dikaryotic strains of the white-rot fungi with respect to their abilities to convert plant cell wall polymers.