• Mycobiology
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• 제40권2호
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• pp.100-106
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• 2012

Interest in commercial cultivation and product development of Cordyceps species has shown a recent increase. Due to its biochemical and pharmacological effects, Cordyceps militaris, commonly known as orange caterpillar fungus, is being investigated with great interest. Cultivation of C. militaris has been practiced on a large scale in order to fulfill a demand for scientific investigation and product development. Isolates of C. militaris can be easily established from both spores and tissue. For isolation of spores, ascospores released from mature stromata are trapped in sterile medium. Multi-ascospore isolates, as well as combinations of single ascospore strains, are used for production of fruiting bodies. Progeny ascospore strains can be isolated from artificial fruiting bodies, thus, the cycle of fruiting body production can be continued for a long period of time. In this study, we examined fruiting body production from multi-ascospore isolates and their progeny strains for three generations. $F_1$ progeny strains generally produced a larger number of fruiting bodies, compared with their mother multi-ascospore isolates; however, $F_2$ and $F_3$ progeny strains produced fewer fruiting bodies. Optimum preservation conditions could help to increase the vitality of the progeny strains. In order to retain the fruiting ability of the strains, further testing of various methods of preservation and different methods for isolation should be performed.

• Mycobiology
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• 제43권1호
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• pp.81-86
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• 2015

To promote the selection of promising monokaryotic strains of button mushroom (Agaricus bisporus) during breeding, 61 progeny strains derived from basidiospores of two different lines of dikaryotic parental strains, ASI1038 and ASI1346, were analyzed by nucleotide sequencing of the intergenic spacer I (IGS I) region in their rDNA and by extracellular enzyme assays. Nineteen different sizes of IGS I, which ranged from 1,301 to 1,348 bp, were present among twenty ASI1346-derived progeny strains, while 15 different sizes of IGS I, which ranged from 700 to 1,347 bp, were present among twenty ASI1038-derived progeny strains. Phylogenetic analysis of the IGS sequences revealed that different clades were present in both the ASI10388- and ASI1346-derived progeny strains. Plating assays of seven kinds of extracellular enzymes (${\beta}$-glucosidase, avicelase, CM-cellulase, amylase, pectinase, xylanase, and protease) also revealed apparent variation in the ability to produce extracellular enzymes among the 40 tested progeny strains from both parental A. bisporus strains. Overall, this study demonstrates that characterization of IGS I regions and extracellular enzymes is useful for the assessment of the substrate-degrading ability and heterogenicity of A. bisporus monokaryotic strains.

• 미생물학회지
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• 제33권2호
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• pp.105-110
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• 1997

한국에서 분리한 U. maydis에서 바이러스 혹은 dsRNA를 가지고 있는 A series와 SH series를 조합하여 옥수수에서 인위적으로 mating시켜 A45, A23, A211, A310, SH614, SH24의 6개 교배형 균주를 분리하였다. 새로운 교배형 균주에서 바이러스 dsRNA를 비교 분석하여 본 결과, mating전 양친형 균주에서 보이고 있는 H, M, L strand의 dsRNA 양상을 모두 가지고 있고 균주간 특별한 molecular exclusion 현상은 보이지 않았다. 교배형 6개으 균주에서 바이러스를 분리하였다. 분리된 바이러스로부터 dsRNA를 분석한 결과 균주간 mating시 dsRNA 재조합을 통한 새로운 encapsidation은 발생하지 않는다는 것을 확인하였다. Toxin test 결과, SH614는 SH9, SH10, SH11 균주에 대해서, A310과 SH24의 2종은 SH11 균주에 대해 특이적 성장억제 현상을 보였다. 이는 mating에 따른 dsRNA의 재조합이 toxin gene의 발현에 영향을 미치지 않는다는 것을 시사한다.

• 한국균학회소식:학술대회논문집
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• 한국균학회 2015년도 추계학술대회 및 정기총회
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• pp.37-37
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• 2015

dsRNA was found in malformed cultures of Lentinula edodes strain FMRI0339, one of the three most popular sawdust cultivated commercial strains of shiitake, and was also found in healthy-looking fruiting bodies and actively growing mycelia. Cloning of the partial genome of the dsRNA revealed the presence of the RdRp sequence of a novel L. edodes mycovirus (LeV), and sequence comparison of the cloned amplicon showed an identical sequence to known RdRp genes of LeV found in strain HKA. The meiotic stability of dsRNA was examined by measuring the ratio of the presence of dsRNA among sexual monokaryotic progeny. More than 40% of the monokaryotic progeny still contained the dsRNA, indicating the persistence of dsRNA during sexual reproduction. Comparing the mycelia growth of monokaryotic progeny suggested that, although variations in the growth rate existed among progeny and virus infection was observed in highly actively growing progeny, there appeared to be a tendency toward a lower frequency of virus incidence in actively growing progeny. This study attempted to cure the edible mushroom L. edodes strain FMRI0339 of the L. edodes mycovirus (LeV) in order to obtain an isogenic virus-free fungal strain as well as a virus-infected strain for comparison. Mycelial fragmentation, followed by being spread on a plate with serial dilutions resulted in a virus-free colony. Viral absence was confirmed with gel electrophoresis after dsRNA-specific virus purification, Northern blot analysis, and PCR using reverse transcriptase (RT-PCR). Once cured, all of fungal cultures remained virus-free over the next two years. Interestingly, the viral titer of LeV varied depending on the culture condition. The titer from the plate culture showed at least a 20-fold higher concentration than that grown in the liquid culture. However, the reduced virus titer in the liquid culture was recovered by transferring the mycelia to a plate containing the same medium. In addition, oxygen-depleted culture conditions resulted in a significant decrease of viral concentration, but not to the extent seen in the submerged liquid culture. Although no $discernable phenotypic changes in colony morphology were observed, virus-cured strains showed significantly higher growth rates and mycelial mass than virus-infected strains. We were also explored effects of LeV on fruiting body formation and mushroom yield. The fruiting body formation yield of virus-free L. edodes was larger than virus-infected L. edodes. These results indicate that LeV infection has a deleterious effect on mycelial growth and fruiting body formation. In addition, we have been investigated host-parasite interaction between L. edodes and its mycovirus interaction to study viral mechanism by establishment of proteomics.

• The Plant Pathology Journal
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• 제29권4호
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• pp.460-464
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• 2013

dsRNA was found in malformed cultures of Lentinula edodes strain FMRI0339, one of the three most popular sawdust cultivated commercial strains of shiitake, and was also found in healthy-looking fruiting bodies and actively growing mycelia. Cloning of the partial genome of the dsRNA revealed the presence of the RdRp sequence of a novel L. edodes mycovirus (LeV), and sequence comparison of the cloned amplicon showed identical sequences sequence to known RNA-dependent RNA polymerase genes of LeV found in strain HKA. The meiotic stability of dsRNA was examined by measuring the ratio of the presence of dsRNA among sexual monokaryotic progeny. More than 40% of the monokaryotic progeny still contained the dsRNA, indicating the persistence of dsRNA during sexual reproduction. Comparing the mycelia growth of monokaryotic progeny suggested that there appeared to be a tendency toward a lower frequency of virus incidence in actively growing progeny.

• Mycobiology
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• 제51권2호
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• pp.109-113
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• 2023

Auricularia is one of the broadly cultivated edible mushrooms in Korea. Most of the Korean Auricularia strains used for cultivation and breeding are known as A. auricula-judae. Recently, this species has been reported to belong to a species complex. Therefore, this study was carried out to genetically clarify the bred and cultivated Korean A. auricula-judae strains. The internal transcribed spacer (ITS) and IGS1 rDNA region sequences were determined from 10 A. auricula-judae strains by PCR and sequencing. Variation in the nucleotide sequence and sequence length of the two rDNA regions were found among the seven A. auricula-judae strains. A maximum-likelihood (ML) phylogenetic tree based on the ITS sequences clearly placed all the 10 Korean A. auricula-judae strains in the A. heimuer clade of the A. auriculajudae complex. A. heimuer is diverged from A. auricula-judae. An ML phylogenetic tree based on the IGS1 sequences revealed the close relationship between Korean A. heimuer strains to Chinese A. heimuer strains. But each strain could be distinguishable by the IGS1 sequence. Furthermore, progeny strains in the seven Korean strains could be differentiated from their parental strains by the IGS1 sequence based phylogenetic tree. Our results are expected to be used to complement the distinction of domestic Auricularia cultivars.

• 한국균학회지
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• 제37권1호
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• pp.114-116
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• 2009

본 연구는 P. capsici의 난포자를 다량으로 확보하기 위하여 우수한 액체 배지를 선발하고 난포자의 발아율을 조사할 뿐만 아니라 $F_1$ progeny를 확보하기 위하여 수행하였다. 공시한 8개 액체배지 중 carrot broth와 V8C broth가 난포자형성을 위해 가장 적당한 배지였다. 총 11균주의 P. capsici(CapA형)과 P. tropicalis(CapB형)를 선발하였고 P. capsici(CapA형)에 P. tropicalis(CapB형)을 교배하는 서로 다른 9개 조합의 교배에서 얻은 난포자로부터 총 129 균주의 $F_1$ hybrid progeny를 얻었으며 난포자의 발아율은 0.64-4.0%(평균 1.85%)이었다.

• Mycobiology
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• 제34권2호
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• pp.61-66
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• 2006

Chestnut blight disease caused by Cryphonectria parasitica is widely distributed throughout chestnut tree plantations in Korea. We surveyed 65 sites located at 9 provinces in South Korea, and isolated 248 virulent and 3 hypovirulent strains of chestnut blight fungus. Hypovirulent strains had dsRNA virus in the cytoplasm, which is one of the typical characteristics of hypovirulent strains. In addition, they showed more characteristics of hypovirulent strains, i.e., suppressed conidiation, reduced pigmentation in colony color, and reduced phenol oxidase activity as well as reduced pathogenicity. Hypovirulent strains, KCPH-22, KCPH-135 and KCPH-136, had a genomic dsRNA band with the molecular weight of 12.7 kb, which is the L-dsRNA of CHV1. They also had a 2.7 kb defective dsRNA band. Single conidia isolated from hypovirulent strains were cultured and various phenotypes and absence of dsRNA bands were obtained from single conidial cultures, which means that hypovirulence transmission is unstable in asexual reproduction and variations in viral heredity by asexual reproduction. Biocontrol trial using hypovirulent strains was also carried out in the chestnut tree plantations, and canker expansion in the treated trees was stopped and healed by callus formation at the margin of the canker. These results show the potentials in successful biocontrol of chestnut blight if the vegetatively compatible hypovirulent strains could be directly used around the canker formed by compatible virulent strains.

• Journal of Microbiology and Biotechnology
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• 제32권8호
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• pp.1047-1053
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• 2022

When ptsG, a glucose-specific phosphotransferase system (PTS) component, is deleted in Escherichia coli, growth can be severely poor because of the lack of efficient glucose transport. We discovered a new PTS transport system that could transport glucose through the growth-coupled experimental evolution of ptsG-deficient E. coli C strain under anaerobic conditions. Genome sequencing revealed mutations in agaR, which encodes a repressor of N-acetylgalactosamine (Aga) PTS expression in evolved progeny strains. RT-qPCR analysis showed that the expression of Aga PTS gene increased because of the loss-of-function of agaR. We confirmed the efficient Aga PTS-mediated glucose uptake by genetic complementation and anaerobic fermentation. We discussed the discovery of new glucose transporter in terms of different genetic backgrounds of E. coli strains, and the relationship between the pattern of mixed-acids fermentation and glucose transport rate.

• Journal of Plant Biotechnology
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• 제34권2호
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• pp.139-144
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• 2007

'정상' 배추의 배축절편을 선발마커로서 paromomycin 저항 성유전자를 갖고 있는 pPTN290으로 각각 형질전환된 EHA101, LBA4404, GV3101균주와 공동배양한 후 갤러스유도배지에서 형질전환캘러스를 얻은 후, 뿌리유도배지에서 부정근을 그리고 신초유도배지에서 신초를 각각 순차적으로 유도하였다. 형질전환캘러스를 얻은 후, 뿌리유도배지에서 부정근을 그리고 신초유도배지에서 신초를 가각 순차적으로 유도하였다. 형질전환캘러스 형성은 Agrobacterium균주에 따라 차이가 있었으며, 특히 EHA101균주에 공동배양된 배축절편으로부터 최대 6.1%까지 얻어졌다. 또한 각각의 형질전환캘러스 클론으로부터 형질전환 부정근과 신초 발생은 EHA101균주에서 60.7%와 38.2%, LBA4404에서 8.3%와 0%, GV3101에서 20.5%와 85.7%까지 각각 얻을 수 있었다. 형질전환식물체는 특별한 형태적 이상 없이 온실에서 정상적으로 자라 $T_{2}$종자를 얻을 수 있었다. GUS방법으로 7개의 후대 유식물체를 분석한 결과 gus유전자가 안정적으로 발현하고 있음을 확인하였고, 배추 genome에 single 또는 multiple copy로 전달되고 있음을 추측할 수 있었다.