Do Galeate-Ascospore Members of the Cephaloascaceae, Endomycetaceae and Ophiostomataceae Share a Common Phylogeny?

Effect of lignocellulosic enzymes on the treatment of mature landfill leachate

The inherent necessity to remediate refractory contaminants from the toxic problematic wastewater like mature landfill leachate (MLL) has become a global challenge. This study investigated the effect of a potentially sustainable technological approach, i.e. lignocellulosic enzymatic activities (lignin-peroxidase, manganese-peroxidase and laccase), produced from six selected fungi on the removal efficiency of chemical oxygen demand (COD) and soluble COD (sCOD) from the MLL. The COD/sCOD removal percentage was significantly increased with higher enzymatic activities. Tyromyces chioneus was revealed to be the first ever fungi that produced significant amount of all three enzymes. Penicillium sp. and Tyromyces chioneus were the most effective strains, which removed 66% and 59% of COD, and 64% and 57% of sCOD, respectively. The maximum lignin-peroxidase, manganese-peroxidase and laccase enzymatic activities were 19.3 and 26.9 U/L by Tyromyces chioneus, and 249.8 U/L by Penicillium sp, respectively. It was concluded that lignocellulosic biomass could be a sustainable and advanced biological treatment option to remove refractory components from MLL.

The mitochondrial genome of Endoconidiophora resinifera is intron rich

Endoconidiophora resinifera (=Ceratocystis resinifera) is a blue-stain fungus that occurs on conifers. The data showed that the Endoconidiophora resinifera mitochondrial genome is one of the largest mitochondrial genomes (>220 kb) so far reported among members of the Ascomycota. An exceptional large number of introns (81) were noted and differences among the four strains were restricted to minor variations in intron numbers and a few indels and single nucleotide polymorphisms. The major differences among the four strains examined are due to size polymorphisms generated by the absence or presence of mitochondrial introns. Also, these mitochondrial genomes encode the largest cytochrome oxidase subunit 1 gene (47.5 kb) reported so far among the fungi. The large size for this gene again can be attributed to the large number of intron insertions. This study reports the first mitochondrial genome for the genus Endoconidiophora, previously members of this genus were assigned to Ceratocystis. The latter genus has recently undergone extensive taxonomic revisions and the mitochondrial genome might provide loci that could be applied as molecular markers assisting in the identification of taxa within this group of economically important fungi. The large mitochondrial genome also may provide some insight on mechanisms that can lead to mitochondrial genome expansion.

Unusual compact rDNA gene arrangements within some members of the Ascomycota: evidence for molecular co-evolution between ITS1 and ITS2

The internal transcribed spacers of the ribosomal DNA tandem repeat were examined in members of the ascomycetous genus Sphaeronaemella. Species of Sphaeronaemella and its mitotic counterpart Gabarnaudia, have a compact rDNA gene arrangement due to unusually short internal transcribed spacer (ITS) regions. Examination of these regions from phylogenetically related taxa, Cornuvesica, Gondwanamyces, and Ceratocystis, showed that their ITS1 and ITS2 regions could be folded into central hairpin-like structures with the size reduction in species of Sphaeronaemella being due to length reduction of the main-hairpin and the loss of smaller hairpin-like structures that emanate from the main hairpin. A databank compilation, combined with newly obtained sequences, provided an ITS data set that includes sequences of 600 species belonging to the Ascomycota. Correlation analysis revealed that the sizes of ITS1 and ITS2 show a strong positive correlation, suggesting that the 2 rDNA regions have co-evolved. This supports biochemical evidence indicating that the ITS1 and ITS2 segments interact to facilitate the maturation of the rRNA precursor.

Fungi vectored by the introduced bark beetle Tomicus piniperda in Ontario, Canada, and comments on the taxonomy of Leptographium lundbergii, Leptographium terebrantis, Leptographium truncatum, and Leptographium wingfieldii

Fungi isolated from Tomicus piniperda (L.) galleries in infected trap logs, standing trees, and directly from insects were identified using morphological features and molecular data obtained from the mitochondrial and nuclear DNA region. Identified strains represented Leptographium wingfieldii Morelet, Leptographium procerum (Kendr.) Wingf., Leptographium lundbergii Lag. & Melin sensu Jacobs & Wingfield, Ophiostoma ips (Rumb.) Nannf., Ophiostoma minus (Hedg.) H. & P. Syd., and Sphaeropsis sapinea sensu lato. Leptographium wingfieldii is believed to be a potentially pathogenic introduced fungus, but sequence data suggest a possible connection between it and the teleomorph of Ophiostoma aureum (Robinson-Jeffrey & Davids.) T.C. Harrington (reported from British Columbia and the western United States). Our data also show that the ex-type culture of Leptographium terebrantis Barras & Perry, a species very similar morphologically to L. wingfieldii, also grouped with L. wingfieldii. We also identified strains of Leptographium truncatum (Wingf. & Marasas) Wingf.; this species has been synonymized with L. lundbergii, but our data indicate that these are distinct species, and therefore, the name L. truncatum should be reinstated. We also report the extended presence of L. procerum in Ontario. Previously viewed as a “southern” species frequently associated with pine-root decline diseases, it has been infrequently reported from New York state and but once each from Ontario and Quebec.

The nuclear small subunit ribosomal genes of Sphaeronaemella helvellae, Sphaeronaemella fimicola, Gabarnaudia betae, and Cornuvesica falcata: phylogenetic implications

Sequences were obtained from the nuclear small subunit ribosomal RNA genes for representatives of four ophiostomatoid genera (Ceratocystis, Gondwanamyces, Cornuvesica, and Sphaeronaemella) to resolve their phylogenetic position within the Ascomycota. Phylogenetic analysis suggests that these genera are monophyletic and share common ancestry with members of the Microascales. Based on sequence data, strains representing the mitotic species Gabarnaudia betae (Delacr.) Samson & W. Gams were shown clearly to be derived from Sphaeronaemella species. Sequences were also obtained from strains representing the syntype of Sphaeronaemella fragariae, the exholotype of Sphaeronaemella humicola, and the extype of Gabarnaudia tholispora. The results suggest that putative extype cultures for S. humicola and G. tholispora no longer represent the original material deposited. Our data also support the exclusion of S. fragariae from Sphaeronaemella. Key words: Cornuvesica, Gabarnaudia, Gondwanamyces, Sphaeronaemalla fragariae, ophiostomatoid fungi, ribosomal DNA.

Notes on Ceratocystis brunnea and some other Ophiostoma species based on partial ribosomal DNA sequence analysis

Ribosomal gene sequence data were obtained from a nonfruiting culture originally identified as Ceratocystis brunnea R.W. Davidson; this species was considered a nomen dubium by Upadhyay (1981) due to a presumptive lack of teleomorph material. The data showed that C. brunnea is a valid species that should be transferred to Ophiostoma, demonstrating that DNA data can compensate for the presumed or actual lack of morphological features lost during either long-term culturing or disintegration of holotype specimens. Use of partial large ribosomal sequence data to assess the relationship of C. brunnea to other Ophiostoma spp. showed that it is not a synonym of Ophiostoma piliferum (Fr.:Fr.) Syd. & P. Syd. as has been suggested; instead, it appears to be distantly related to Ophiostoma piceae (Münch) Syd. & P. Syd. The data obtained for the Ophiostoma piliferum strains included in this study suggest that hardwood-derived isolates may be distinct from those obtained from conifers. In addition, molecular characters support transferring Ceratocystis pseudonigra Olchow. & Reid, Ceratocystiopsis concentrica (Olchow. & Reid) Upadhyay, Ceratocystiopsis pallidobrunnea (Olchow. & Reid) Upadhyay, and Ceratocystiopsis crenulata (Olchow. & Reid) Upadhyay to Ophiostoma.Key words: rDNA, phylogenetics, Ophiostoma piliferum, Ophiostoma, Ceratocystsis.

Phylogenetic relationships in Leptographium based on morphological and molecular characters

Species of Leptographium Lagerberg & Melin are characterized by mononematous conidiophores with dark stipes and conidiogenous apparatuses with complex series of branches. These fungi generally inhabit woody substrates, are associated with bark beetles (Coleoptera: Scolytidae) and cause blue-stain in conifers. Few phylogenetic studies have been conducted on Leptographium species, and those that have been undertaken have been focused on a small number of species. The objective of this study was to investigate the phylogenetic relationships among species in Leptographium based on partial DNA operon sequences and to ascertain whether morphological characters are congruent with DNA-based phylogeny. Morphological characters were analyzed and compared with results from DNA sequence analysis. Results indicate that there are three groups within Leptographium based on DNA sequence analysis. There was, however, no congruence between these groups and those emerging from morphological characters. Data from this study strongly support the connection between Leptographium and Ophiostoma Sydow & Sydow. They also provide us with an objective means to confirm the identity of many Leptographium species that are difficult to distinguish based on morphological characters.Key words: Leptographium, phylogeny, morphology, Ophiostoma, rRNA.

On the phylogeny of members of Ceratocystis s.s. and Ophiostoma that possess different anamorphic states, with emphasis on the anamorph genus Leptographium, based on partial ribosomal DNA sequences

Phylogenetic analysis of partial ribosomal DNA sequences was undertaken to assess the phylogenetic distribution of ophiostomatoid anamorphs with an emphasis on members of Leptographium and the generic limits of Ceratocystis sensu lato Ell. & Halst. Molecular data identified one group of Ophiostoma species with anamorphs assignable to Pesotum and Leptographium that appears to be monophyletic. This study also showed that, based on molecular characters, Pesotum pini (Hutchison & Reid) Okada and all Leptographium strains tested, including L. terebrantis Barras & Perry, L. lundbergii Lag. & Melin, and L. procerum (Kendr.) Wingf., could be placed among Ophiostoma species. With regard to the anamorphs of Ophiostoma, we determined that the separation of Leptographium from Pesotum, although convenient, is artificial. The partial ribosomal DNA sequences also confirm that Europhium should be considered a synonym of Ophiostoma. The phylogenetic position of species of Ceratocystis sensu lato with Chalara-like, Knoxdaviesia, and Gabarnaudia anamorphs is also discussed.Key words: Ceratocystis, Ophiostoma, Leptographium, partial rDNA sequences, phylogeny.

Developments in fungal taxonomy

Fungal infections, especially those caused by opportunistic species, have become substantially more common in recent decades. Numerous species cause human infections, and several new human pathogens are discovered yearly. This situation has created an increasing interest in fungal taxonomy and has led to the development of new methods and approaches to fungal biosystematics which have promoted important practical advances in identification procedures. However, the significance of some data provided by the new approaches is still unclear, and results drawn from such studies may even increase nomenclatural confusion. Analyses of rRNA and rDNA sequences constitute an important complement of the morphological criteria needed to allow clinical fungi to be more easily identified and placed on a single phylogenetic tree. Most of the pathogenic fungi so far described belong to the kingdom Fungi; two belong to the kingdom Chromista. Within the Fungi, they are distributed in three phyla and in 15 orders (Pneumocystidales, Saccharomycetales, Dothideales, Sordariales, Onygenales, Eurotiales, Hypocreales, Ophiostomatales, Microascales, Tremellales, Poriales, Stereales, Agaricales, Schizophyllales, and Ustilaginales).

A molecular phylogenetic reappraisal of theGraphiumcomplex based on 18S rDNA sequences

Based on nuclear encoded small subunit (18S) rDNA sequences, a taxonomic reappraisal of Graphium (anamorphic fungi) was undertaken using neighbour-joining (NJ) and fast DNA maximum likelihood (fastDNAml) methods and compared with traditional classifications. In common with Graphium putredinis, Graphium penicillioides (the lectotype species) was found to be related to the Microascales, not the Ophiostomatales as previously believed. Both species might be heterogenous and should be treated as species aggregates. The representative mode of conidiogenesis for these two species was nodular-annellidic, rather than the dense-annellidic mode characteristic of the synnematous ophiostomatalean anamorphs. Graphium is emended to be restricted to G. penicillioides, G. putredinis, and related synnematous anamorphs of Petriella and Pseudallescheria, and a nomenclator for the nine species presently accepted in Graphium is presented. Pesotum, originally characterized mainly by sympodial conidiogenesis, is emended to include synnematous anamorphs of Ophiostoma species formerly included in a variety of genera with sympodial to dense-annellidic conidiogenesis. Eight new combinations in Pesotum are included in a nomenclator for the 26 species currently known. Three new combinations from Ceratocystis to Ophiostoma are proposed for species with Pesotum anamorphs. The holomorph of Graphium calicioides has affinities to the black yeasts and should be classified in the Chaetothyriales. However, the critical morphological, loculoascomycetous characters of the teleomorph are not completely documented. Interpreted from the molecular context, the morphological similarities between these three groups of anamorphs are homoplasies and examples of convergent evolution.Key words: Chaetothyriales, Graphium, Microascales, Ophiostomatales, Pesotum, 18S (SSU) rDNA sequences.

Molecular relationships among hyphal ascomycetous yeasts and yeastlike taxa

The circumscription of mycelial genera among the ascomycetous yeasts has been controversial because of widely different interpretations of the taxonomic significance of their phenotypic characters. Relationships among species assigned to mycelial genera were determined from extent of divergence in a ca. 600-nucleotide region near the 5′ end of the large subunit (26S) ribosomal DNA gene. Phylogenetic analyses showed that Stephanoascus is distinct from Zygoascus and that Blastobotrys, Sympodiomyces, and Arxula represent anamorphs of the Stephanoascus clade. The analyses demonstrated the following teleomorphic taxa to be congeneric: Ambrosiozyma/Hormoascus, Saccharomycopsis/Guilliermondella/Botryoascus/Arthroascus, Dipodascus/Galactomyces, and Eremothecium/Ashbya/Nematospora/Holleya. Species assigned to Dipodascus comprise two separate clades. New taxonomic combinations are proposed that reflect the phylogenetic relationships determined. Key words: mycelial yeasts, ribosomal rRNA/rDNA, molecular systematics.

Ascomal evolution of filamentous ascomycetes: evidence from molecular data

Phylogenetic analyses of nucleotide data from partial sequences (1150 bp) of the small subunit ribosomal DNA (SSU rDNA) were performed on 30 taxa representing several orders of Hymenoascomycetes and Loculoascomycetes. These analyses detected four major groups of filamentous ascomycetes: group 1, pyrenomycetes (Hypocreales, Microascales, Diaporthales, Sordariales) and loculoascomycetes (Pleosporales); group 2, operculate discomycetes (Pezizales); group 3, inoperculate discomycetes (Geoglossaceae); and group 4, plectomycetes (Eurotiales, Onygenales) and loculoascomycetes (Chaetothyriales). Well-supported clades, which correspond to groupings based on ascomal morphology, were resolved; however, the monophyly of the classes Hymenoascomycetes and Loculoascomycetes was rejected. The placement of the root on the filamentous ascomycete ingroup proved more problematic than resolving the ingroup relationships. Three alternative rooting possibilities, which were identified in suboptimal parsimony trees, were not significantly less likely in maximum likelihood ratio tests. Nonetheless, the most likely topology obtained from fastDNAml was identical to the most parsimonious tree. Key words: filamentous ascomycetes, Hymenoascomycetes, Loculoascomycetes, parsimony, maximum likelihood, ribosomal DNA.

Relationships among the genera Ashbya, Eremothecium, Holleya and Nematospora determined from rDNA sequence divergence

Species of the genera Ashbya, Eremothecium, Holleya, and Nematospora were compared from extent of divergence in a 580-nucleotide region near the 5' end of the large subunit (26S) ribosomal DNA gene. The four genera are closely related and comprise a subclade of the hemiascomycetes. Because the taxa show little divergence, it is proposed that all be placed in the genus Eremothecium. The family Eremotheciaceae, fam. nov., is proposed.

Molecular taxonomy of the yeasts

The term 'yeast' is often taken as a synonym for Saccharomyces cerevisiae, but the phylogenetic diversity of yeasts is illustrated by their assignment to two taxonomic classes of fungi, the ascomycetes and the basidiomycetes. Subdivision of taxa within their respective classes is usually made from comparisons of morphological and physiological features whose genetic basis is often unknown. Application of molecular comparisons to questions in yeast classification offers an unprecedented opportunity to re-evaluate current taxonomic schemes from the perspective of quantitative genetic differences. This review examines the impact of molecular comparisons, notably rRNA/rDNA sequence divergence, on the current phenotypically defined classification of yeasts. Principal findings include: 1) budding ascomycetous yeasts are monophyletic and represent a sister group to the filamentous ascomycetes, 2) fission yeasts are ancestral to budding and filamentous ascomycetes, 3) the molecular phylogeny of basidiomycetous yeasts is generally congruent with type of hyphal septum, presence or absence of teliospores in the sexual state, and occurrence of cellular xylose.

Systematics of the ascomycetous yeasts assessed from ribosomal RNA sequence divergence

Extent of divergence in partial nucleotide sequences from large and small subunit ribosomal RNAs was used to estimate genetic relationships among ascomycetous yeasts and yeastlike fungi. The comparisons showed four phylogenetically distinct groups comprised of the following taxa: Group 1. The budding yeasts Saccharomyces, Saccharomycopsis, Debaryomyces, Metschnikowia, Saturnospora, and Lipomyces, and the yeastlike genera Ascoidea, Cephaloascus, Dipodascus, Dipodascopsis, and Galactomyces; Group 2. Eremascus, Emericella and Ceratocystis; Group 3. Taphrina and Protomyces; Group 4. Schizosaccharomyces. Because of the genetic relationships indicated by sequence analysis, Group 1 taxa are retained in the order Endomycetales, and Schizosaccharomyces is retained in the Schizosaccharomycetales Prillinger et al. ex Kurtzman.