• Mycobiology
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• 제44권4호
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• pp.269-276
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• 2016

Aspergillus luchuensis is known as an industrially important fungal species used for making fermented foods such as awamori and shochu in Japan, makgeolli and Meju in Korea, and Pu-erh tea in China. Nonetheless, this species has not yet been widely studied regarding mating-type genes. In this study, we examined the MAT1-1 and MAT1-2 gene ratio in black koji molds (A. luchuensis, Aspergillus niger, and Aspergillus tubingensis) and in Aspergillus welwitschiae isolated from Meju, a fermented soybean starting material for traditional soy sauce and soybean paste in Korea. The number of strains with the MAT1-1 locus was 2 of 23 (A. luchuensis), 6 of 13 (A. tubingensis), 21 of 28 (A. niger), and 5 of 10 (A. welwitschiae). Fungal species A. tubingensis and A. welwitschiae showed a 1 : 1 ratio of MAT1-1 and MAT1-2 mating-type loci. In contrast, A. luchuensis revealed predominance of MAT1-2 (91.3%) and A. niger of MAT1-1 (75%). We isolated and identified 2 A. luchuensis MAT1-1 strains from Meju, although all strains for making shochu in Japan are of the MAT1-2 type. These strains may be a good resource for breeding of A. luchuensis to be used in the Asian fermented-food industry.

• 한국버섯학회지
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• 제9권1호
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• pp.3-16
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• 2011

In the bipolar basidiomycete Pholiota nameko, a pair of homeodomain protein genes located at the A mating-type locus regulates mating compatibility. In the present study, we used a DNA-mediated transformation system in P. nameko to investigate the homeodomain proteins that control the clamp formation. When a single homeodomain protein gene (A3-hox1 or A3-hox2) from the A3 monokaryon strain was introduced into the A4 monokaryon strain, the transformants produced many pseudo-clamps but very few clamps. When two homeodomain protein genes (A3-hox1 and A3-hox2) were transformed either separately or together into the A4 monokaryon, the ratio of clamps to the clamp-like cells in the transformants was significantly increased to approximately 50%. We, therefore, concluded that the gene dosage of homeodomain protein genes is important for clamp formation. When the sip promoter was connected to the coding region of A3-hox1 and A3-hox2 and the fused fragments were introduced into NGW19-6 (A4), the transformants achieved more than 85% clamp formation and exhibited two nuclei per cell, similar to the dikaryon (NGW12-163 ${\times}$ NGW19-6). The results of real-time RT-PCR confirmed that sip promoter activity is greater than that of the native promoter of homeodomain protein genes in P. nameko. So, we concluded that nearly 100% clamp formation requires high expression levels of homeodomain protein genes and that altered expression of the A mating-type genes alone is sufficient to drive true clamp formation.

• Mycobiology
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• 제38권1호
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• pp.26-32
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• 2010

The cyclic AMP (cAMP) pathway plays a major role in growth, sexual differentiation, and virulence factor synthesis of pathogenic fungi. In Cryptococcus neoformans, perturbation of the cAMP pathway, such as a deletion in the gene encoding adenylyl cyclase (CAC1), causes defects in the production of virulence factors, including capsule and melanin production, as well as mating. Previously, we performed a comparative transcriptome analysis of the Ras- and cAMP- pathway mutants, which revealed 163 potential cAMP-regulated genes (38 genes at a 2-fold cutoff). The present study characterized the role of one of the cAMP pathway-dependent genes (serotype A identification number CNAG_ 06576.2). The expression patterns were confirmed by Northern blot analysis and the gene was designated cAMP-regulated gene 1 (CAR1). Interestingly, deletion of CAR1 did not affect biosynthesis of any virulence factors and the mating process, unlike the cAMP-signaling deficient cac1$\Delta$ mutant. Furthermore, the car1$\Delta$ mutant exhibited wild-type levels of the stress-response phenotype against diverse environmental cues, indicating that Car1, albeit regulated by the cAMP-pathway, is not essential to confer a cAMP-dependent phenotype in C. neoformans.

• 한국미생물·생명공학회지
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• 제29권4호
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• pp.212-220
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• 2001

S. cerevisiae HBC52와 S, diataticus K114 의 rare mating 에 의해 개발된 HCS 균주들은 크기가 약 $13\mu\textrm{m}$ karyotype 분석결과 K114 균주에만 있는 약 1150kb 분자량을 가지는 염색체 band를 유지하였으며 전분을 분해하여 halo 를 형성하였다. Glucoamylase 활성은 약 2.7~3.4 unti/ml 를 가진 균주임이 밝혀졌으며 당 발효실험과 응집성 실험을 수행한 결과 HBC52 균주와 유사한 당 발효특성을 보이고 응집성 특성도 약응집성의 floculation type으로 비슷하였다. 그리고 HCS 균주의 포자형성과 피막형성 유무 실험에서는 양조효모인 HBC52 균주와 같이 포자가 형성되지 않았으며, 피막도 형성되지않았다. 균주들의 최종당도 실험은 HBC52균주가 약 68%의 발효수준을 나타냈고, HCS 균주들은 이 보다 높은 76~78%의 수준을 보였따. 즉 HBC52 균주가 최종당도($ 2.00^{\circ}$P)를 보인 반면 HCS 균주들은 ($0.7~0.93^{\circ}$P)를 보이는 결괄르 나타내어 맥주양조에서 low carbohydrate beer를 생산할 수있음이 확인되었다.

• The Plant Pathology Journal
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• 제15권3호
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• pp.131-136
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• 1999

In fungi known as ascomycetes, ability to mate is controlled by a single mating type (MAT) locus with two dissimilar sequences called idiomorphs carrying genes encoding transcription factors that are unrelated to each other. Fungi requiring strains with different MAT genes to complete the sexual process are heterothallic (self-sterile); species in which as single strain is able to undergo sexual reproduction are homothallic (self-fertile). Previous analysis of sequences from several heterothallic and homothallic species of the ascomycete genus Cochliobolus showed that homothallics evolve from heterothallics and that each known Cochliobolus homothallic species arose independently, from a different heterothallic ancestral species. Here we report detailed comparative analyses of MAT sequences ad their flanking regions, and show that: (1) The level of MAT gene similarity is not correlated with reproductive life style; (2) MAT proteins from all Cochliobolus species are conserved within the transcription factor signature sequences; they are not conserved in the carboxy terminal half of MAT-1, or third of MAT-2, except in those from very closely related species; (3) A gene (ORF1) of unknown function, consistently found on the MAT flank, is more conserved than are the MAT genes themselves; (4) The intergenic sequences diverge sharply among species.

• Journal of Microbiology and Biotechnology
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• 제27권7호
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• pp.1223-1232
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• 2017

Cordyceps militaris, a member of Ascomycota, a mushroom referred to as caterpillar Dong-chung-ha-cho, is commercially valuable because of its high content of bioactive substances, including cordycepin, and its potential for artificial cultivation. Cordycepin (3'-deoxyadenosine) is highly associated with the pharmacological effects of C. militaris. C. militaris is heterothallic in that two mating-type loci, idiomorph MAT1-1 and MAT1-2, exist discretely in two different spores. In this study, nine C. militaris strains were mated with each other to prepare newly bred strains that produced a larger amount of cordycepin than the parent strains. Nine strains of C. militaris were identified by comparing the internal transcribed spacer sequence, and a total of 12 single spores were isolated from the nine strains of C. militaris. After the MAT idiomorph was confirmed by PCR, 36 mating combinations were performed with six single spores with MAT1-1 and the others with MAT1-2. Eight mating combinations were successfully mated, producing stroma with perithecia. Cordycepin content analysis of all strains by high-performance liquid chromatography revealed that the KASP4-bred strain produced the maximum cordycepin among all strains, regardless of the medium and stroma parts. Finally, universal rice primer-PCR was performed to demonstrate that the bred strains were genetically different from the parental strains and new C. militaris strains. These results may be related to the recombination of genes during mating. The newly produced strains can be used to meet the industrial demand for cordycepin. In addition, breeding through mating suggests the possibility of producing numerous cordycepin-producing C. militaris strains.

• Journal of Microbiology and Biotechnology
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• 제28권9호
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• pp.1573-1579
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• 2018

Transcriptional gene silencing is regulated by the chromatin structure, which is by various factors including histones. Saccharomyces cerevisiae contains transcriptionally silenced regions such as telomeric regions and hidden mating (HM) loci. The positively-charged amino acids on the histone H4 tail were reported to be critical for the telomeric silencing in yeast, by interacting with Dot1, a specific methyltransferase for the $79^{th}$ lysine on histone H3. However, Dot1 did not affect gene silencing within HM loci, but whether the positively-charged amino acids on the H4 tail affect HM silencing has not been defined. To elucidate the function of the H4 tail on HM silencing, we created several MATa-type yeast strains bearing the substitution of arginine with alanine or lysine on the histone H4 tail and checked the sensitivity of MATa-type yeast to alpha pheromone. The arginine point mutants substituted by alanine (R17A, R19A, and R23A) did not show sensitivity to alpha pheromone, but only two arginine mutants substituted by lysine (R17K and R19K) restored the sensitivity to alpha pheromone-like wild type. These data suggested that the basic property of arginine at $17^{th}$ and $19^{th}$ positions in the histone H4 tail is critical for maintaining HM silencing, but that of the $23^{rd}$ arginine is not. Our data implicated that the positive charge of two arginine residues on the histone H4 tail is required for HM silencing in a manner independent of Dot1.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.85.1-85
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• 2003

In most ascomycetes, a single mating type locus, MAT, with two alternate forms (MAT1-1 and MAT1-2) called idiomorphs, controls mating ability. In heterothallic ascomycetes these alternate idiomorphs reside in different nuclei. In contrast, most homothallic ascomycetes carry both MAT1-1 and MAT1-2 in a single nucleus, usually closely linked. An example of the latter is Gibberella zeae, a producer of mycotoxins such as trichothecene and zearalenone that threaten human and animal health. We asked if G. zeae could be made strictly heterothallic by manipulation of MAT. Targeted gene replacement was used to differentially delete MAT1-1 or MAT1-2 from a wild type haploid MAT1-1 MAT1-2 strain, resulting in MAT1-1；mat1-2, mat1-1；MAT1-2 strains that were self-sterile, yet able to cross to wild type testers and more importantly, to each other. These results indicated that differential deletion of MAT idiomorphs eliminates selfing ability of G. zeae, but the ability to outcross is retained. To our knowledge, this is the first report of complete conversion of fungal reproductive strategy from homothallic to heterothallic by targeted manipulation of MAT. Practically, this approach opens the door to simple and efficient procedures for obtaining sexual recombinants of G. zeae that will be useful for genetic analyses of mycotoxin production and other traits, such as ability to cause disease.

• Mycobiology
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• 제46권1호
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• pp.64-71
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• 2018

The aim of this study was to investigate the pattern of distribution of mating type (MAT) genes of Tuber indicum in ectomycorhizosphere soils from natural T. indicum-producing areas and cultivated truffle orchards and ascocarp samples from different regions. Quantitative real-time PCR and multiplex PCR were used to weight the copy numbers of MAT1-1-1 and MAT1-2-1 in natural truffle soils and cultivated orchard soils. The effect of limestone on the pattern of truffle MAT genes and the correlation between soil properties and the proportion of MAT genes were also assessed. These results indicated that an uneven and nonrandom distribution of MAT genes was common in truffle-producing areas, cultivated truffle orchards, and ascocarps gleba. The competition between the two mating type genes and the expansion of unbalanced distribution was found to be closely related to truffle fructification. Limestone treatments failed to alter the proportion of the two mating type genes in the soil. The content of available phosphorus in soil was significantly correlated with the value of MAT1-1-1/MAT1-2-1 in cultivated and natural ectomycorhizosphere soils. The application of real-time quantitative PCR can provide reference for monitoring the dynamic changes of mating type genes in soil. This study investigates the distributional pattern of T. indicum MAT genes in the ectomycorhizosphere soil and ascocarp gleba from different regions, which may provide a foundation for the cultivation of T. indicum.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2022년도 추계학술대회
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• pp.191-191
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• 2022

Heterostyly continues to fascinate evolutionary biologists interested in heredity, evolution, breeding, and adaptive function. Polymorphism demonstrates how simply inherited developmental changes in the location of plant sexual associations can have important consequences for population pollination and mating biology. In contrast to homozygous self incompatibility, only a small number of mating phenotypes can be maintained in the population because insect pollinators have limitations in achieving multiple segregation sites for pollen deposition. Field studies of pollen tube growth have shown that reciprocal style-stamen polymorphisms function to increase the capacity of insect-mediated cross-pollination. The genetic pattern of style morphs is well established in various taxa, but despite recent advances, the identity, number, and structure of the genes controlling the heteromorphic syndrome have been poorly elucidated. The phenomenon of heterostyly in buckwheat has been controlled by gene complex concentrate to S-locus. Homomorphic autogamous buckwheat strains were established by the interspecific hybridization. Backcrossing of this line to the common buckwheat (pin) and selecting homostylar progenies made it possible to introduce the self-compatible gene into common buckwheat. In the result, we obtained the BC₉F₂ generation, and defined the strong linkage between flower type and self-incompatibility by microscopic observation of pollen tube growth. This finding suggests that self-incompatibility character is not controlled by one gene. Moreover, we defined the strong linkage between flower type and self-incompatibility. It strongly supports the S supergene theory. Therefore, we have plan to elucidate the heterostyly self-incompatibility by using molecular genetics, proteome analysis and apply to exploitation of buckwheat improvement. In near future, the expression of heterozygous syndromes in genus Fagopyrum with single isolated heterozygous species may provide clues to early stages of polymorphic assembly and shed light on evolutionary models of heterozygous strains.