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Ganoderma lucidum has a long history of use as a traditional medicine in Asian countries. However, the taxonomy of Ganoderma species remains controversial, since they were initially classified on the basis of their morphological characteristics. Recently, it was proposed that G. lucidum from China be renamed as G. sichuanense or G. lingzhi. In the present study, phylogenetic analysis using the internal transcribed spacer region rDNA sequences of the Ganoderma species indicated that all strains of the Korean 'G. lucidum' clustered into one group together with G. sichuanense and G. lingzhi from China. However, strains from Europe and North American, which were regarded as true G. lucidum, were positioned in a clearly different group. In addition, the average size of the basidiospores from the Korean cultivated Yeongji strains was similar to that of G. lingzhi. Based on these results, we propose that the Korean cultivated Yeongji strains of 'G. lucidum' should be renamed as G. lingzhi.

The aim of this study was to identify and characterize new Flammulina velutipes laccases from its whole-genome sequence. Of the 15 putative laccase genes detected in the F. velutipes genome, four new laccase genes (fvLac-1, fvLac-2, fvLac3, and fvLac-4) were found to contain four complete copper-binding regions (ten histidine residues and one cysteine residue) and four cysteine residues involved in forming disulfide bridges, fvLac-1, fvLac-2, fvLac3, and fvLac-4, encoding proteins consisting of 516, 518, 515, and 533 amino acid residues, respectively. Potential N-glycosylation sites (Asn-Xaa-Ser/Thr) were identified in the cDNA sequence of fvLac-1 (Asn-454), fvLac-2 (Asn-437 and Asn-455), fvLac-3 (Asn-111 and Asn-237), and fvLac4 (Asn-402 and Asn-457). In addition, the first 19~20 amino acid residues of these proteins were predicted to comprise signal peptides. Laccase activity assays and reverse transcription polymerase chain reaction analyses clearly reveal that CuSO4 affects the induction and the transcription level of these laccase genes.

Laccase activity of Pleurotus ostreatus is significantly increased by the addition of apple pomace. Among various conditions, the best concentration of apple pomace and cultivation time for the production of laccase by P. ostreatus was 2.5% and 9 days, respectively. Reverse transcription polymerase chain reaction analyses of laccase isoenzyme genes, including pox1, pox3, pox4, poxc, poxa3, and poxa1b, revealed a clear effect of apple pomace on transcription induction. Our findings reveal that the use of apple pomace can be a model for the valuable addition of similar wastes and for the development of a solid-state fermenter and commercial production of oyster mushroom P. ostreatus.

In the present study, a phylogenetic analysis was undertaken based on the internal transcribed spacer (ITS) rDNA and partial β-tubulin gene sequence of the Ganoderma species. The size of the ITS rDNA regions from different Ganoderma species varied from 625 to 673 bp, and those of the partial β-tubulin gene sequence were 419 bp. Based on the results, a phylogenetic tree was prepared which revealed that Korean Ganoderma lucidum strains belong in a single group along with a G. lucidum strain from Bangladesh.

The oyster mushroom, Pleurotus ostreatus, is one of the most widely cultivated mushrooms in the world (Baars et al., 2000). Mushrooms are economically important biotechnological products and their market has markedly expanded across the world in the past few decades. Mushrooms, the fruiting bodies of basidomycetes, have been traditionally consumed as a food and also have been considered as some of the potential nutraceuticals (Chang et al., 1996; Kues et al., 2000). The oyster mushroom is a popular cultivated mushroom along with the white button mushroom, Agaricus bisporus. Techniques for its cultivation are similar to those used for A. bisporus that the fungi are grown on various organic composts. Many microorganisms are known to promote the growth of P. ostreatus and other cultivated mushrooms (Cho et al., 2003). The microorganisms found in the casing layers are especially important for induction of fruiting body formation (Eger, 1961, 1972; Grewal and Rainey, 1992; Rainey et al., 1990). Particluarly, the growth and development of A. bisporus are known to be affected by fluorescent Pseudomonas (Cho et al., 2003; Grewal and Rainey, 1992). To date, detailed studies on the interaction between edible fungi and bacteria have been primarily conducted with strains of Pseudomonas putida, which initiate basidiome formation and stimulate fungal growth. Recent work has revealed that the interaction is closely related to the rate of hyphae extension and the formation of primodia (Rainey, 1991). On the contrary, the roles of the fluorescent Pseudomonas in the cultivation of P. ostreatus are less understood. The current method of forcing mushroom mycelia to change from the vegetative to the reproductive phase involves the application of a covering of some suitable materials (the casing layer) on the surface of the spawn compost (Hume and Hyes, 1972; Mac Canna and Flanagan, 1972; Peerally, 1979). The casing also functions to supply and conserve moisture for the mushrooms and their rhizomorphs as well as to act as the transport system for dissolved nutrients. There can be a wide variation in the yields of mushrooms depending on different casing layer materials, leading to the question of the affect of the biological properties of the various casing layers. Based on recent studies involving A. bisporus, there is also considerable interest in the use of bio-augmentation with mushroom-promoting Pseudomonas to improve the consistency of different casing layers for production. Accordingly, the primary purpose of this study was to compare the population of microorganisms and mushroom-production in sterilized casing layers with those in non-sterilized casing layers.

The oyster mushroom (Pleurotus ostreatus) is one of the most important edible mushrooms worldwide. The mechanism of P. ostreatus fruiting body development has been of interest both for the basic understanding of the phenotypic change of the mycelium-fruiting body and to improve breeding of the mushrooms. Based on our previous publication of P. ostreatus expressed sequence tag database, 1,528 unigene clones were used in macroarray analysis of mycelium, fruiting body and basidiospore developmental stages of P. ostreatus. Gene expression profile databases generated by evaluating expression levels showed that 33, 10, and 94 genes were abundantly expressed in mycelium, fruiting body and basidiospore developmental stages, respectively. Among them, the genes specifically expressed in the fruiting body stage were further analyzed by reverse transcription-polymerase chain reaction and Northern blot to investigate temporal and spatial expression patterns. These results provide useful information for future studies of edible mushroom development.

Restriction enzyme-mediated integration (REMI) was used to transform uracil auxotrophs of Pleurotus ostreatus to prototrophy. When protoplasts of Pleurotus ostreatus were treated by the reaction mi...