• The Korean Journal of Mycology
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• v.39 no.2
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• pp.99-104
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• 2011

Shiitake breeding requires the procedures of mating of two different parental strains and selection of hybrid strains that have good traits for the mushroom production. In this study, we tested the possibility of the use of chromogenic plate-based assay for extracellular enzyme production in order to assess and find good biochemical properties-possessed hybrid strains that were generated from genetic cross of the monokaryotic strains derived from two different parental strains of Lentinula edodes Sanjo-101ho and Sanjo-108ho. We observed that there was difference in the ability of producing ${\beta}$-glucosidase, avicelase, CM-cellulase, amylase, pectinase, xylanase, and protease among the monokaryotic strains. We could also comparatively assess that the ability of the seven extracellular enzymes production in the hybrid strains depended on the mating combination of the monokaryotic strains. Our results demonstrate that the assessment method for extracellular enzyme production using chromogenic plate assay could be usefully applied to the assessment of the hybrid strains derived from the breeding procedure of L. edodes.

• The Korean Journal of Mycology
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• v.42 no.1
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• pp.86-90
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• 2014

Button mushroom (Agaricus bisporus) strains from diverse origins were compared in this study to obtain basic information on their growth and biochemical properties that are helpful for breeding. Among 31 dikaryotic strains tested, most strains showed better mycelial growth on oatmeal agar than on MEA and PDA. Mycelia of the mushroom strains revealed ${\beta}$-glucosidase activity the most clearly among the seven extracellular enzymes tested. All the strains showed protease activity, but ${\beta}$-glucosidase activity was found in 27 strains and xylanase activity was found in 30 strains. The activity of avicelase, CM-cellulase, amylase, and pectinase was detected in less than 20 strains. These results implied that enzymatic characteristics could be used as a criterion of strain selection for breeding study.

• Journal of Microbiology
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• v.44 no.3
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• pp.363-368
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• 2006

In this study, native Byadyrhizobium strains were isolated from the host plant, Glycine max, harvested from fields in Madhya Pradesh, India, and were typed by Iytic rhizobiophages. Eight indigenous (Soy2, ASR011, ASR031, ASR032, MSR091, ISR050, ISR076 and ISR078) and two exotic strains (USDA123 and CB1809), all of which evidenced a distinct reaction with six phages, were employed in this study. The symbiotic interaction of these strains was studied initially using soybean cultivar JS335 in a sand culture in a controlled environment, and the efficiency was assessed based on the nodule number, nodule dry weight, plant dry weight, nitrogenase activity, and total accumulation of N per plant. Symbiotic effectiveness was found to be highest with the native phage-sensitive isolate ASR011, whereas it was at a minimum with the phage-resistant isolates, ISR050 and ISR078. Additionally, the effectiveness of these strains was evaluated using six soybean cultivars belonging to different maturity groups; namely, Brags, Lee, Pusa20, PK416, JS33S and NRC37. Analysis of variance data evidenced significant differences due to both symbionts, for the majority of the tested parameters. The CB1809, USDA123, and ASR011 strains evidenced relatively superior symbiotic effectiveness with soybean cultivars Brags, Lee and JS335. Strain ISR078 evidenced no significant responses with any of the cultivars. The ASR031 strain performed moderately well with all tested cultivars. The symbiotic response of all the strains was quite poor with cultivar PK416. Our studies showed that a significant relationship existed between the phage sensitivity and symbiotic efficiency of the bacterial strains with the host-cultivars.

• Mycobiology
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• v.49 no.4
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• pp.376-384
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• 2021

Agaricus bisporus is a popular edible mushroom that is cultivated worldwide. Due to its secondary homothallic nature, cultivated A. bisporus strains have low genetic diversity, and breeding novel strains is challenging. The aim of this study was to investigate the genetic diversity and population structure of globally collected A. bisporus strains using simple sequence repeat (SSR) markers. Agaricus bisporus strains were divided based on genetic distance-based groups and model-based subpopulations. The major allele frequency (MAF), number of genotypes (NG), number of alleles (NA), observed heterozygosity (HO), expected heterozygosity (HE), and polymorphic information content (PIC) were calculated, and genetic distance, population structure, genetic differentiation, and Hardy-Weinberg equilibrium (HWE) were assessed. Strains were divided into two groups by distance-based analysis and into three subpopulations by model-based analysis. Strains in subpopulations POP A and POP B were included in Group I, and strains in subpopulation POP C were included in Group II. Genetic differentiation between strains was 99%. Marker AB-gSSR-1057 in Group II and subpopulation POP C was confirmed to be in HWE. These results will enhance A. bisporus breeding programs and support the protection of genetic resources.

• The Korean Journal of Mycology
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• v.49 no.3
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• pp.405-412
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• 2021

Wolfiporia cocos is an important medicinal fungus that has been used in regions of Northeast Asia including Korea, Japan, and China. W. cocos is classified in Korea into two types (red bokryeong and white bokryeong) based on the internal colors (yellow orange-pale pink and white) of the sclerotium. Generally, the W. cocos type cultivated on farms produces white sclerotium. In this study, we endeavored to select strains that form sclerotium in sawdust medium using 2-way cross-breeding among two cultivated strains and three wild strains. Monospores were isolated from the fruiting bodies of cultivated and wild strains on potato dextrose agar. Thirty-nine strains of 338 hybrid strains isolated formed sclerotia with white or yellow colors upon culture for 3 months in Pinus densiflora sawdust medium. Selection for sclerotium forming strains using sawdust culture follows a very simple and easy procedure that is presented for the first time in this paper. We plan to test selected strains in the field to aid in developing new varieties for the future.

• The Plant Pathology Journal
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• v.31 no.2
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• pp.97-107
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• 2015

Alteration of genetic make-up of the isolates and mono-sporidial strains of Tilletia indica causing Karnal bunt (KB) disease in wheat was analyzed using DNA markers and SDS-PAGE. The generation of new variation with different growth characteristics is not a generalized feature and is not only dependant on the original genetic make up of the base isolate/monosporidial strains but also on interaction with host. Host determinant(s) plays a significant role in the generation of variability and the effect is much pronounced in monosporidial strains with narrow genetic base as compared to broad genetic base. The most plausible explanation of genetic variation in presence of host determinant(s) are the recombination of genetic material from two different mycelial/sporidia through sexual mating as well as through parasexual means. The morphological and development dependent variability further suggests that the variation in T. indica strains predominantly derived through the genetic rearrangements.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.3
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• pp.278-284
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• 1994

The sulfur amino acid composition in soybean (Glycine max L.) seeds may be an essential characteristic of new cultivars for some animal diets. Variation in seed storage protein among genotypes might make it possible to improve the quality of seed protein by genetically altering seed storage protein composition through plant breeding. This study was carried out to determine if mutant strains have potential for improving seed protein quality in soybean. Ten mutant strains had a distinct characteristic of seed storage protein subunits. Among the mutant strains, the sulfur amino acid compositions(methionine plus cystein) of Keburi(P.I.417016), Keburi(P.I.506817), and P.I.54608-1 were relatively higher than those of the others and were 1.9, 2.1, and 1.8%, repectively, which might be due to low levels of ${\alpha}$, ${\alpha}$', and ${\beta}$ subunits of 7S protein. Therefore, it is concluded that the mutant strains, Keburi(P.I.417016), Keburi(P.I.506817), and P.I.54608-1 appear to be potential materials for a breeding program for improving sulfur amino acid composition, and the others also seem to be possible breeding materials for other uses.

• The Plant Pathology Journal
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• v.19 no.3
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• pp.171-176
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• 2003

The complete nucleotide sequences of the genomic RNAs of Soybean mosaic virus strains GS (SMV-G5) and G7H (SMV-G7H) were determined and compared with sequences of other SMV strains. Each viral RNA was determined to be 9588 nucleotides in length excluding the poly (A) tail and contained an open reading frame to encode a polyprotein subsequently processed into up to ten proteins by proteolytic cleavage. Com-parison of the amino acid sequences with those of other SMV strains showed high percentage of amino acid sequence homology with the same genome organization. The nucleotide and the deduced amino acid sequences between SMV-G5 and SMV-G7H were greater than 99% identity. When compared with those of other SMV strains in a phylogenetic analysis of the nucleotide and deduced amino acid sequences, they formed a distinct virus clade showing over 97％ amino acid identity, but were more distantly related to the other potyvirus (44.1-69.6% identity). Interestingly, SMV G7H strain caused a severe mosaic or necrosis symptom in soybean cultivars including Jinpum-1, Jinpum-2, and Sodam, whereas, no symptom was observed in SMV-G5 inoculation. Complete nucleotide sequences of these strains will give clues for determining symptom determinant(s) in future research.

• Mycobiology
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• v.36 no.4
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• pp.270-273
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• 2008

Trichoderma spp. cause large crop losses of the cultivated shiitake mushroom, Lentinula edodes. We bred several shiitake strains that are resistant to Trichoderma spp. using di-mon mating to establish a useful method for controlling the greenmold disease. We examined the competitive ability of L. edodes against Trichoderma spp. using a dual culture system to select resistant strains. By screening Trichoderma-resistant strains, we found that among 11 parental strains, 4 strains, including KFRI 36, were confirmed resistant strains. They showed especially strong resistance to T. harzianum, which formed deadlock after mycelial contact and then invaded into the territory of T. harzianum. KFRI 171 also showed resistance to T. atroviride strains. Among 13 strains, which were made by hybridization of shiitake strains, 5 were confirmed to be resistant to Trichoderma, including KFRI 58-1. Their resistance was not correlated to the resistant activity of their parents’ strains. Two strains lose resistance and two strains acquire resistance compared to their parents’ strains. In SEM observation, the mycelium of L. edodes at the interaction zone of Lentinula-Trichoderma was rugged and swollen by T. harzianum.

• Journal of Mushroom
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• v.4 no.1
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• pp.1-32
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• 2006

According to UPOV (International Union for Protection of New Varieties of Plants), mushroom spawn market have to be opened by the year 2009. Number of commercial strains distributed by the year 2005 were 179 of 24 species of edible and medicinal mushrooms. Only nine strains of oyster mushrooms were registered as protected variety, which is not compatible with those recorded in other advanced countries. Meaning of spawn in broad sense contains commercial strains. Development of commercial strains faces two main problems in Korea : One is the complicated genetic patterns and sexuality of mushroom species, and the other is expensive experimental equipments and fruiting body growing houses. Resolution of these problems leads to development of mushroom strains. This could be achieved as follows; genetic resources collection and assessment, molecular characterization of useful genetic characters, development of new commercial strains by hybridization using typical genetic resources, strengthening of breeding research using "Mushroom Breeding Group", management of spawn research company by consortium, foundation of mushroom general industry, promotion of consumption, and upgrade of competition ability for other countries. These points are under discussion.