• 한국균학회소식:학술대회논문집
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• 2014.10a
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• pp.42-42
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• 2014

Mating of tetrapolar mushrooms is regulated by to chromosomal loci, A and B. A locus contains A gene that expresses a homeodomain protein whereas B locus contains multiple pheromones and receptor genes. In order to characterize the mating loci in Korean cultivated strains of Lentinula edodes, one hundred monokaryotic myclelia were isolated from the basidiospores of cultivated strains, including Cham-A-Ram, Sanjo701, and Sanjo707. Both mating loci were amplified using primer sets targeting conserved sequence regions for homeodomain (HD), pheromone, and receptor genes. Subsequent sequence analysis revealed that the Korean strains contained significant variations in the homeodomain of A locus, even within the same A1 or A2 mating type. Similarly, B locus was also highly diversified in the sequences of pheromones and receptors as well as gene organization. These results enabled us to design mating type-specific probes which can distinguish mating type of each strain. The specificity was confirmed by between intra- and inter-strain mating experiment.

• The Korean Journal of Mycology
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• v.26 no.4 s.87
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• pp.574-582
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• 1998

Five basidiocarps of Pholiota species have been collected from the areas of BubJu Temple for last two years, and identified to those of P. adiposa or Pholiota species. The taxonomy of these basidiocarps with the morphological aspects was compared with the analysis obtained from the polymorphisms of PCR-RAPD bands made after reacted with the random primers. The polymorphic variations were observed within the species of the basidiocarps, but not between genomic DNA's of the mycelia obtained and the basidiocarps. Several different bands made from the primers (28 and 36) in PCR-RAPD reactions were identified within the genus of Pholiota and speculated to be specific for the individual basidiocarp of P. adiposa collected. The primers employed here were considered to be very useful for distinguishing the individual isolates or basidiocarps collected from the fields. Also, the basidiospores were obtained from the sporeprints of the above basidiocarps as a simple agar and confirmed with observations of clamp connection under microscopes. The matings of them indicated the 'tetrapolar' type, being different from the 'bipolar' type reported by Japanese basidiocarps of P. adiposa or P. nameko. Based on our work, the edible fungi collected were speculated to be a new breeding resource for those of Pholiota commercialized in Japan.

• Journal of Mushroom
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• v.7 no.4
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• pp.141-149
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• 2009

The sexual incompatibility system was investigated in the new strain Pleurotus ostreatus 'Miso'. Matings among monosporous progeny collected from fruiting bodies revealed that the new oyster mushroom is heterothallic and has a tetrapolar mating system. Single basidiospore isolates that did not have clamp connections were determined to be monokaryotic. Compatible parings of monokaryons were distinguishable macroscopically by the rapid growth and gross morphology to some extent but they were distinguished obviously by the presence of clamp connections from incompatible pairings under microscopic examination. Rarely dikaryotization was unidirectional with clamp connections only at the margin of one side of mating. In tetrapolarity of matings, four kinds of patterns, A1B1, A1B2, A2B1, and A2B2, were decided depending on compatibility tests in a parental strain with a mating factor of A1A2B1B2. The mating tests with the tester strains were performed for the detection of mating types on the rest of selected monokaryons.

• Journal of Mushroom
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• v.10 no.3
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• pp.101-108
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• 2012

Pleurotus ostreatus 'Miso' is a mutant strain showing white color in pileus from the known parent strain 'Wonhyeong 1'. Shape and several other characters also vary with culture conditions. Mating experiments were performed to understand interstrain mating relationship using monokaryons of the parent and the mutant strains. All monokaryons were grown from single spores isolated from freshly collected fruit bodies. Pairings were performed in 90 mm petri dishes on PDA. They were allowed to grow at 25 until two fronts of the advancing mycelia met and developed a conspicuous contact zone. The contact zone and the outer edges of paired colonies on each plate were examined for clamp connections. The parent and the mutant resulted in tetrapolar incompatibility in intrastrain crosses. In interstrain crosses, each monokaryotic tester strain of the parent strain was out-crossed to monokaryotic tester strains of the mutant. As a result of these crosses it was found that both strains share the same A and B incompatibility factors yielding 25% compatibility.

• 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.

• The Korean Journal of Mycology
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• v.49 no.4
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• pp.487-495
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• 2021

Lentinula edodes is a tetrapolar basidiomycete and its mating type is determined by two unlinked genetic loci, A and B. Theoretically, one dikaryotic strain could produce basidiospores with four different mating types in a 1:1:1:1 ratio. Previous studies have described the skewed segregation ratio of mating types among basidiospores of L. edodes. However, they were based only on morphological characteristics, such as clamp connection, to determine mating types. To clarify whether the segregation distortion of mating types is a general phenomenon in L. edodes, we analyzed the mating types of basidiospores obtained from three cultivars of L. edodes using recently developed DNA markers. We found that the skewed segregation of mating types was strain-specific, as reported previously. Among the three cultivars, one cultivar showed balanced segregation, while the other two displayed distorted segregation. We also examined the relationship between mating type and mycelial growth rate of monokaryons derived from each basidiospore. It was found that the monokaryotic mycelial growth rate was related to the A mating type but not to the B mating type. Therefore, homeodomain transcription factor genes that reside on the A locus or other genes linked to the A locus affect the growth rate of monokaryotic mycelia. Considering the importance of mating types in mushroom breeding, this study is informative for establishing an efficient breeding strategy as well as for understanding the mechanism of monokaryotic mycelial growth.

• The Korean Journal of Mycology
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• v.48 no.4
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• pp.389-396
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• 2020

Lentinula edodes is one of the most widely consumed edible mushrooms in Korea. Mating in L. edodes is regulated by a tetrapolar system, and two unlinked genetic loci, A and B, are known to be major determinants of the mating types, as reported in other heterothallic basidiomycetes. The A locus of L. edodes encodes a pair of homeodomain (HD) transcription factors. The highly variable N-termini of these HD transcription factors contribute to the diversity among the A mating types. In this study, we developed a cleaved amplified polymorphic sequence (CAPS) marker to discriminate 11 different A mating type alleles predominant among both cultivated and wild strains. Amplification of the variable region of the A locus followed by digestion with HaeIII and EcoRI restriction enzymes enabled successful discrimination among the 11 A mating type alleles. We also evaluated the applicability of this method in the identification of two A mating types of a dikaryotic strain.

• Journal of Mushroom
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• v.2 no.3
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• pp.115-126
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• 2004

Somatic hybrids of inter-compatible and inter-incompatible strains were obtained by protoplast fusion. The fusion products between compatible strains, Pleurotus ostreatus and P. florida, formed heterokaryons, while fusants between incompatible strains such as P. cornucopiae + P. florida, P. ostreatus + Ganoderma applanatum, P. florida + Ganoderma lucidum, and P. ostreatus + Flammulina velutipes formed synkaryons that retained genes from both parents. The heterokaryons showed the same level of basidioma development. In contrast, the synkaryons showed unique characteristics including clamp connection formation at mitosis, either partner basidioma development, and abnormal segregation and recombination compared with inter-compatible strains. Synkaryons can be classified into homokaryoyic and heterokaryotic type. A comparison of somatic hybrids with compatible and incompatible strains was made using random amplified polymorphic DNA (RAPD) analysis. The heterokaryons between compatible species showed the same level of variability and contained both parental RAPD bands. In contrast, most of the synkaryons between incompatible species showed similarity to those of either parental bands and non-parental RAPD bands. Synkaryons can be classified into microgenome insertion type and macrogenome insertion type. A tetrapolar mating system was found among monospore isolates in somatic hybrids and wild type P. ostreatus. Homokaryons from each somatic hybrid combination were paired with tester homokaryons of the initial wild type of P. ostreatus. The changed mating types were identified in progenies. The pattern of mating type switching in somatic hybrids depends on compatibility of fusion partner. There are several factors related to the mechanism of clamp connection formation and fruiting body development of synkaryons. Of these,the major factor may be associated with self-fertility and mating type switching such as homokaryotic fruiting of wild type P. ostreatus. This review will discuss these aspects.