• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.6
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• pp.440-446
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• 2004

Interest in in vitro study of entomopathogenic fungi, including Cordyceps species, has been increasing due to their valuable bioactive compounds and biocontrol effects. Among Cordyceps species, in vitro stromata of C militaris has been successfully produced and cultivated for industrial purposes. However, genetic study on in vitro stromata formation of C militaris has not been carried out yet. Here, relationship between mating system and perithecial stromata formation of C militaris is reported. Mating system was determined by observing perithecial stromata formation from mono-ascospore cultures and their pair-wise combinations. Certain combinations of mono-ascospore strains produced perithecial club-shaped stromata, whereas other combinations produced either no stromata or only abnormal non-perithecial stromata. Similarly, mono­ascospore cultures without combination produced either no stromata or only abnormal non­perithecial stromata. Despite obvious heterothallism, self-fertility was occasionally observed in few strains of C militaris. These observations indicated that C militaris behaves as a bipolar het­erothallic fungus and requires two mating compatible strains in order to produce regular club­shaped perithecial stromata, a fundamental requirement for its industrial cultivation.

• 한국균학회소식:학술대회논문집
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• 2009.10a
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• pp.76-95
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• 2009

In the fungal genus Cordyceps, the type species Cordyceps militaris produces bioactive ingredients and exhibits medicinal effects as a Traditional Chinese Medicine (TCM), The fruiting bodies of C.militaris have now been mass-produced artificially and used as functional food and medicine in China. The unstable variation in forming fruiting body is however a key restrictive factor in industrial production. The genetic study on in vitro stromata formation of C. militaris has rarely been carried out. Here, we report the effects of genetic variation including the mating system on perithecial stromata formation of C. militaris. Monoconidial isolates which have both MAT1-1-1 and MAT1-2-1(genotype MAT1-1/2) could produce stromata. While the isolates only have either MAT1-1-1 or MAT1-2-1 (genotype MAT1-1 or MAT1-2) failed to produce stromata. Despite obvious heterothallism, homothallism was occasionally observed in a few isolates of C. militaris. High genetic variation was observed amongst the different monoconidial isolates of C. militaris. The unstable variation or lose of fruiting body formation was found to be caused by the inner-species high genetic variation of C. militaris. These results also indicated that C. militaris sexually behaved as both heterothallic and homothallic and required two mating type compatible in the same culture in order to produce regular clubshaped perithecial stromata.

• Mycobiology
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• v.38 no.4
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• pp.282-285
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• 2010

Cordyceps cardinalis successfully produced its fruiting bodies from multi-ascospore isolates. However, subcultures of multiascospore isolates could not produce fruiting bodies after few generations. Fruiting body production also differed from sector to sector of the same isolate. Single ascospore isolates were then co-inoculated in combinations of two to observe the fruiting characteristics. Combinations of certain isolates produced perithecial stromata formation, whereas other combinations did not produce any fruiting bodies. These results show that C. cardinalis is a heterothallic fungus, requiring two isolates of opposite mating types for fruiting body production. It was also shown that single ascospore isolates are hermaphrodites.

• 한국균학회소식:학술대회논문집
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• 2015.11a
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• pp.35-35
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• 2015

Pleurotus eryngii has recently become a major cultivated mushroom; it uses tetrapolar heterothallism as a part of its reproductive process. Sexual development progresses only when the A and B mating types are compatible. Such mating incompatibility occasionally limits the efficiency of breeding programs in which crossing within loci-shared strains or backcrossing strategies are employed. Therefore, understanding the mating system in edible mushroom fungi will help provide a short cut in the development of new strains. We isolated and identified pheromone and receptor genes in the B3 locus of P. eryngii and performed a functional analysis of the genes in the mating process by transformation. A genomic DNA library was constructed to map the entire mating-type locus. The B3 locus was found to contain four pheromone precursor genes and four receptor genes. Remarkably, receptor PESTE3.3.1 has just 34 amino acid residues in its C-terminal cytoplasmic region; therefore, it seems likely to be a receptor-like gene. Real-time quantitative RT-PCR (real-time qRT-PCR) revealed that most pheromone and receptor genes showed significantly higher expression in monokaryotic cells than dikaryotic cells. The pheromone genes PEphb3.1 and PEphb3.3 and the receptor gene PESTE3.3.1 were transformed into P5 (A3B4). The transformants were mated with a tester strain (A4B4), and the progeny showed clamp connections and a normal fruiting body, which indicates the proposed role of these genes in mating and fruiting processes. This result also confirms that PESTE3.3.1 is a receptor gene. In this study, we identified pheromone and receptor genes in the B3 locus of P. eryngii and found that some of those genes appear to play a role in the mating and fruiting processes. These results might help elucidate the mechanism of fruiting differentiation and improve breeding efficiency.

• Journal of Mushroom
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• v.4 no.2
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• pp.48-52
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• 2006

Oyster mushroom, Pleurotus ostreatus is bifactorial heterothallism. Single basidiospore isolates from fruiting bodies are homokaryotic and self-sterile. However, we found that homokaryons derived from some strains of P. ostreatus could develop fruiting bodies with two different types. One hundred and two isolates out of 155 monospore isolates formed fruiting bodies (65.8%). First group did not have only mature or sporulating fruiting bodies but also clamp connections, which initial isolate also did not present clamp connections (Abortive homokaryotic fruiting, AHF). Second group had developed fruiting bodies with clamp connections even though initial homokaryotic colony did not form clamp connections (Pseudo- homokaryotic fruiting, PHF). The mycelial colonies derived from PHF by tissue culture formed clamp connections, while mycelial colonies of AHF lacked them. We obtained 535 PHF and 79 AHF inter-strain hybrids among 8 strains of P. ostreatus by hyphal anastomosis. The fruiting body yield of PHF group is higher than that of AHF group in bottle cultivation. A preselection of single spore isolates for fertility would save labour in strain improvement of P. ostreatus.