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Plastic waste has a negative impact on marine ecosystems and the quantity of this source of anthropogenic pollution continues to increase. Several studies have investigated plastic biodegradation using various microorganisms. In this study, we isolated fungi from polyethylene terephthalate (PET) waste on Korean seacoasts and evaluated their ability to degrade plastic by comparing the diameters of the clear zones they formed on polycaprolactone (PCL) agar. We isolated 262 strains from 47 plastic waste sources and identified 108 fungal species via molecular methods. The PCL agar assay revealed that 87 species presented with varying degrees of PCL degradation capacity. Among them, certain fungal species were strong PCL degraders. The present study demonstrated the possibility that some fungi inhabiting plastic could potentially degrade it in the marine environment. We believe that the discoveries made herein lay theoretical and practical foundations for the development of novel bioremediation systems for marine plastispheres and help mitigate the environmental pollution issues related to plastic wastes.

The genomes of two Penicillium strains were sequenced and studied in this study: strain 2HH was isolated from the digestive tract of Anobium punctatum beetle larva in 1979 and the cellulase hypersecretory strain S1M29, derived from strain 2HH by a long-term mutagenesis process. With these data, the strains were reclassified and insight is obtained on molecular features related to cellulase hyperproduction and the albino phenotype of the mutant. Both strains were previously identified as Penicillium echinulatum and this investigation indicated that these should be reclassified. Phylogenetic and phenotype data showed that these strains represent a new Penicillium species in series Oxalica, for which the name Penicillium ucsense is proposed here. Six additional strains (SFC101850, SFCP10873, SFCP10886, SFCP10931, SFCP10932 and SFCP10933) collected from the marine environment in the Republic of Korea were also classified as this species, indicating a worldwide distribution of this new taxon. Compared to the closely related strain Penicillium oxalicum 114-2, the composition of cell wall-associated proteins of P. ucsense 2HH shows five fewer chitinases, considerable differences in the number of proteins related to β-D-glucan metabolism. The genomic comparison of 2HH and S1M29 highlighted single amino-acid substitutions in two major proteins (BGL2 and FlbA) that can be associated with the hyperproduction of cellulases. The study of melanin pathways shows that the S1M29 albino phenotype resulted from a single amino-acid substitution in the enzyme ALB1, a precursor of the 1,8-dihydroxynaphthalene (DHN)-melanin biosynthesis. Our study provides important knowledge towards understanding species distribution, molecular mechanisms, melanin production and cell wall biosynthesis of this new Penicillium species.

This study was conducted to generate information regarding the diversity of fungi inhabiting creosote-treated wood in a storage yard for crosstie wastes in Gwangmyeong, Korea. Additionally, the resistance to polycyclic aromatic hydrocarbons (PAHs) of indigenous fungi that mainly occupy creosote-treated wood was evaluated. We isolated fungi from the surface and inner area of crosstie wastes and identified them using a combination of traditional methods and molecular techniques. Overall, 179 isolates including 47 different species were isolated from 240 sampling sites. The identified fungal species included 23 ascomycetes, 19 basidiomycetes, and 5 zygomycetes. Three species, Alternaria alternata, Irpex lacteus, and Rhizomucor variabilis, were the most frequently isolated ascomycetes, basidiomycetes, and zygomycetes, respectively. The results of this study showed that there was a large difference in the fungal diversity between the surface and the inner area. Additionally, zygomycetes and ascomycetes were found to have a greater tolerance to PAHs than basidiomycetes. However, two basidiomycetes, Heterobasidion annosum and Schizophyllum commune, showed very high resistance to PAHs, even in response to the highest concentration (1,000 ppm), which indicates that these species may play a role in the degradation of PAHs.

A new species, Trichoderma songyi, was found to be associated with the pine mushroom (Tricholoma matsutake) in Korea. This species was isolated from three different substrates: Tricholoma matsutake basidiomata, as well as roots of Pinus densiflora and soil in the fairy ring. Based on its molecular and phenotypic characteristics, we demonstrate that Trichoderma songyi is unique and distinguishable from closely related species. We performed phylogenetic analyses based on two molecular markers, the genes for both translation elongation factor 1-alpha and the second largest subunit of RNA polymerase II. Phylogenetic analyses showed that Trichoderma songyi is closely related to Trichoderma koningii aggregate and Trichoderma caerulescens. Morphologically, Trichoderma songyi can be distinguished from these closely related taxa by its growth rates, colony morphology on PDA in darkness, and coconut-like odour. Due to the economic importance of the pine mushroom, the relationship between Trichoderma songyi and Tricholoma matsutake should be studied further.

In this study, basidiomycete isolates that possessed a strong ability to degrade chromated copper arsenate (CCA)-treated wood were characterized. These fungal isolates, which were collected from CCA-treated pine log wastes, showed no recognizable morphological properties on culture media. Nucleotide sequence analysis of the large subunit rDNA of the isolates revealed that they were one species. Based on the high sequence similarity (>95%) and close phylogenetic relationship with several known species of Crustoderma, the fungal isolates characterized in this study were classified as a Crustoderma sp. In a wood degradation test, Crustoderma isolate KUC8611 produced a remarkably higher weight loss in CCA-treated Pinus radiata (68.7%), Pseudotsuga menziesii (39.7%), and Tsuga heterophylla (38.5%) wood than other evaluated basidiomycete species, including Crustoderma flavescens and Crustoderma corneum. In addition, extracellular enzymes for cellulose and protein degradation were detected when the isolates were cultured in chromogenic media, which supports the finding that isolate KUC8611 is a wood degrader. Furthermore, an in vitro test for metal tolerance revealed that isolate KUC8611 showed strong arsenic tolerance, but that it could not tolerate copper. Finally, isolate KUC8611 produced lower amounts of oxalic acid than copper-tolerant fungi such as Fomitopsis palustris and Antrodia vaillantii. To the best of our knowledge, this is the first study to report the degradation of CCA-treated wood by a Crustoderma species.

Phellinus sulphurascens Pilat causes laminated root rot of coniferous species in both western North America (WNA) and Asia. Accurate somatic incompatibility tests for mapping population structures have been difficult to conduct for P. sulphurascens because no single, unambiguous criterion has allowed differentiation of homokaryotic and heterokaryotic isolates. In a population study of P. sulphurascens in WNA, two types of ITS sequences were found in the single spore and vegetative isolates. All single spore isolates (SSIs) had either ITS type-1 or type-2 whereas some vegetative isolates had both ITS types. The segregation pattern for inheritance of ITS, which we observed in SSIs from eight basidiocarps, suggested that each ITS type occurred in a different nucleus and that each basidiospore inherited only one ITS type. In four SSIs from Russia and eight heterokaryotic isolates from Japan, nine different ITS types, referred to as type-3 to -11, were detected. A variety of pairing tests conducted between known Asian and WNA homokaryon and heterokaryon isolates did not always give consistent results with respect to fungal mat morphologies and formation of demarcation lines. However, the ITS types that occurred after pairing tests did follow consistent patterns. Thus, using ITS polymorphisms and pairing tests between Asian tester isolates and 49 vegetative isolates from WNA, we were able to accurately distinguish between homokaryotic and heterokaryotic isolates.

The work reported here investigated the fungal community inhabiting western redcedar fence material with a focus on species colonizing wood below the surface, of which little is known. From seven pieces of fence material, twenty-three different fungal species were isolated and characterized using both traditional morphology and molecular identification methods. The species identified included thirteen ascomycetous and ten basidiomycetous fungi. Isolates were tested for their resistance to beta-thujaplicin - one of the principle fungicidal agents of western redcedar heartwood extractives. Generally, ascomycetous fungi exhibited greater resistance to beta-thujaplicin than basidiomycetous fungi. Interestingly, three ascomycetous and two basidiomycetous species frequently isolated had high tolerance to this compound. These species could be candidate 'pioneer' species that invade and detoxify western redcedar extractives, paving the way for colonization by decay fungi.