• Korean Journal of Veterinary Research
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• v.28 no.1
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• pp.115-118
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• 1988

Mating experiments were performed to, elucidate the distribution of perfect state of Microsporum gypseum complex originated from animals and soils in Korea. A total of 30 strains of M. gypseum complex, composed of 16 from animals and 14 from soils, ere mated with the tester strains of Nannizzia incurvata, N. gypsea and N. fulva. Among 30 strains of M. gypseum complex examined, 16 strains(53.3%) were N. incurvata, 13 strains(43.3%) N. gypsea and 1 strain (3.3%) N. fulva. Among 13 strains of dog isolates, 8 strains(61.5%) were N. incurvata and 5 strains(38.5%) N. gypsea. And each strain isolated from Korean native goat, monkey and albino rat was N. gypsea. Among 14 strains of soil isolates, 8 strains(57.2%) were N. incurvata, 5 strains (35.7%) N. gypsea and 1 strain(7.2%) N. fulva. And -mating type was more frequently observed than +mating type in the strains of N. incurvata and N. gypsea. By this study, N. fulva was isolated the first time in Korea.

• Mycobiology
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• v.46 no.1
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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.

• Journal of Mushroom
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• v.9 no.1
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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.

• Research in Plant Disease
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• v.20 no.1
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• pp.25-30
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• 2014

Phytophthora infestans was isolated from potato leaves collected from main potato producing areas in Korea during 2009-2011. In 2009, 99 isolates tested were all A1 mating type. Two of 64 isolates in 2010 and two of 78 isolates in 2011 were A2 mating type and they were found only in Miryang area. Among 99 isolates examined in 2009, 13.1% was resistant to metalaxyl, 3.1% was intermediate resistant and 83.8% was sensitive. In 2010, 19.4% of 62 isolates was resistant, 4.8% was intermediate and 75.8% was sensitive. Metalaxyl resistant, intermediate and sensitive isolates collected in 2011 were 23.1%, 9.0% and 67.9%, respectively. Metalaxyl resistant isolates increased mainly in winter cropping areas and seed potato producing areas where fungicides were sprayed more often. Frequencies of isolates showing minimum inhibition concentration of dimethomorph at $1.0-5.0{\mu}g/ml$ were 17.2% in 2009, 19.0% in 2010 and 15.4% in 2011. However, there was no evidence for occurrence of resistant isolate to dimethomorph because no isolate was able to grow at $5.0{\mu}g/ml$.

• 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.50 no.5
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• pp.374-381
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• 2022

In the mating of filamentous basidiomycetes, dikaryotic mycelia are generated through the reciprocal movement of nuclei to a monokaryotic cytoplasm where a nucleus of compatible mating type resides, resulting in the establishment of two different dikaryotic strains having the same nuclei but different mitochondria. To better understand the role of mitochondria in mushrooms, we created four sets of dikaryotic strains of Lentinula edodes, including B2×E13 (B2 side) and B2×E13 (E13 side), B5×E13 (B5 side) and B5×E13 (E13 side), E8×H3 (E8 side) and E8×H3 (H3 side), and K3×H3 (K3 side) and K3×H3 (H3 side). The karyotypes and mitochondrial types of the dikaryotic strains were successfully identified by the A mating type markers and the mitochondrial variable length tandem repeat markers, respectively. Comparative analyses of the dikaryotic strains on the mycelial growth, substrate browning, fruiting characteristics, and mitochondrial gene expression revealed that certain mitochondria are more effective in the mycelial growth and the production of fruiting body, possibly through the activated energy metabolism. Our findings indicate that mitochondria affect the physiology of dikaryotic strains having the same nuclear information and therefore a selection strategy aimed at mitochondrial function is needed in the development of new mushroom strain.

• Tribology and Lubricants
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• v.4 no.2
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• pp.28-35
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• 1988

A general and efficient algorithm is proposed for the analysis of the frictionless elastic contact problems. It utilizes a simplex-type algorithm with a modified entry rule and incoporates finite element method to obtain flexibility matrices. The algorithmic solution is compared with the Hertzian solution for the contact problem between two cylinders to prove its accuracy and the contact problem between pin and piston rod is solved and compared with the numerical results of Frankavilla and Zienkiewicz to demonstrate the generality and effectiveness of the suggested algorithm. The contact problem between mating involute gear teeth at the worst load position is considered. The computed contact stress is smaller than the result of Hertz's theory applied to the contact between two kinematically equivalent discs and the contact area is larger than that of Hertz's theory.

• The Plant Pathology Journal
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• v.15 no.3
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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.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.12
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• pp.1805-1811
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• 2007

A simulation study was conducted to evaluate the effect of reciprocal cross on the detection and characterization of parent-of-origin (POE) QTL in $F_2$ QTL populations. Data were simulated under two different mating designs. In the one-way cross design, six $F_0$ grand sires of one breed and 30 $F_0$ grand dams of another breed generated 10 $F_1$ offspring per dam. Sixteen $F_1$ sires and 64 $F_1$ dams were randomly chosen to produce a total of 640 $F_2$ offspring. In the reciprocal design, three $F_0$ grand sires of A breed and 15 $F_0$ grand dams of B breed were mated to generate 10 $F_1$ offspring per dam. Eight $F_1$ sires and 32 $F_1$ dams were randomly chosen to produce 10 $F_2$ offspring per $F_1$ dam, totaling 320 $F_2$ offspring. Another mating set comprised three $F_0$ grand sires of B breed and 15 $F_0$ grand dams of A breed to produce the same number of $F_1$ and $F_2$ offspring. A chromosome of 100 cM was simulated with large, medium or small QTL with fixed or different allele frequencies in parental breeds. A series of tests between Mendelian and POE models were applied to characterize QTL as Mendelian, paternal, maternal or partial expression QTL. The overall detection powers were similar between the two mating designs. However, the proportions of paternally expressed QTL that were declared as paternal QTL type were greater in the reciprocal cross design than in the one-way cross, and vice versa for Mendelian QTL. When QTL alleles were segregating in parental breeds, a significant proportion of Mendelian QTL were spuriously declared POE QTL, suggesting that care must be taken to characterize imprinting QTL in a QTL mapping population with a small number of $F_1$ parents.

• The Korean Journal of Mycology
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• v.20 no.3
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• pp.222-228
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• 1992

Pleurotus florida was transformed by complementation of auxotrophic mutant using chimeric plasmid containing Flammulina velutipes leu 2 gene and pBR 322 replicon. Mycelial morphology of transformants was grown and compared on mushroom complete and minimal medium. Transformants were mated with monokaryon and their genetic recombination was investigated for the morphology of fruitbody and spore analysis. $Leu^+$ transformant showed same mating type of $A_1B_1$ as to the untransformed mutant. The transformant and the untransformed mutant were mated with monokaryon of which mating type is $A_2B_1$, respectively. Although fruitbody of the untransformed mutant was not produced, $leu^+$ transformant produced fruitbody. Spore analysis showed that leucine requiring spores from fruitbody of $leu^+$ transformant were diminished when compared with those of untransformed mutant.