• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.117.3-118
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• 2003

We tested for the presence of double-stranded RNA (dsRNA) mycovirus in 827 Fusarium graminearum isolated from diseased barley and maize. dsRNA mycoviruses with various sizes were isolated. Of them, it was previously reported that dsRNA from DK2l isolate had pronounced morphological changes, including reduction in mycelial growth, increased to red pigmentation, reduced virulence and sporulation. (Chu et al., Appl. Environ. Microbiol. 2002). For better understanding of this hypovirulence associated with DK2l dsRNA virus, we determined the complete nucleotide sequence of dsRNA genome and named Fusarium hypovirus DK2l strain (Fhv-DK2l ). Genomic RNA of Fhv-DK2l was determined to be 6625 nucleotides in length excluding the poly (A) tail and contained three putative open reading frame. RNA-dependent RNA polymerase (RdRp) and helicase domain were expected in ORF A, 54 to 4709 nucleotide position. ORE B, 4752 to 5216 nucleotide position, and ORF C, 5475 to 6578 nucleotide position, were predicted to encode 16.7kDa and 41.3kDa protein respectively each. We could not detect any conserved domains from these two proteins. Phylogenetic analysis showed Fhv-DK2l was related to Cryphonectria hypovirus 3. Ten additional isolates were found that were infected with dsRNA mycoviruses. These mycoviruses contain 2 to 4 different segments of dsRNAs with the size range of approximately 1.7 to 10-kbp in length. The presence of dsRNAs isolates did not affect colony morphology and were transmissible through conidia and ascospore with incidence of 30-100％. These results indicate that there is genomic diversity of dsRNA mycoviruses that infect F. graminearum isolates and that impact of virus infection on host's morphology and virulence is determined by the interaction between dsRNAs and the fungal host, not by the mere presence of the dsRNAs

• The Plant Pathology Journal
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• v.36 no.1
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• pp.11-28
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• 2020

Faba bean (Vicia faba L.) is one of the most important legume crops in Egypt. However, production of faba bean is affected by several diseases including fungal diseases. Fusarium wilt incited by Fusarium oxysporum Schlecht. was shown to be the most common wilt disease of faba bean in Assiut Governorate. Evaluation of 16 faba bean genotypes for the resistance to Fusarium wilt was carried out under greenhouse conditions. Three molecular marker systems (inter-simple sequence repeat [ISSR], sequence related amplified polymorphism [SRAP], and simple sequence repeat [SSR]) and a biochemical marker (protein profiles) were used to study the genetic diversity and detect molecular and biochemical markers associated with Fusarium wilt resistance in the tested genotypes. The results showed that certain genotypes of faba bean were resistant to Fusarium wilt, while most of the genotypes were highly susceptible. The percentage of disease severity ranged from 32.83% in Assiut-215 to 64.17% in Misr-3. The genotypes Assiut-215, Roomy-3, Marut-2, and Giza2 were the most resistant, and the genotypes Misr-3, Misr-1, Assiut-143, Giza-40, and Roomy-80 performed as highly susceptible. The genotypes Assiut-215 and Roomy-3 were considered as promising sources of the resistance to Fusarium wilt. SRAP markers showed higher polymorphism (82.53%) compared with SSR (76.85%), ISSR markers (62.24%), and protein profile (31.82%). Specific molecular and biochemical markers associated with Fusarium wilt resistance were identified. The dendrogram based on combined data of molecular and biochemical markers grouped the 16 faba bean genotypes into three clusters. Cluster I included resistant genotypes, cluster II comprised all moderate genotypes and cluster III contained highly susceptible genotypes.

• Korean Journal of Environmental Agriculture
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• v.31 no.1
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• pp.52-59
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• 2012

BACKGROUND: Cultivation of genetically modified(GM) crops rapidly has increased in the global agricultural area. Among those, herbicide resistant GM crops are reported to have occupied 89.3 million hectares in 2010. However, cultivation of GM crops in the field evoked the concern of the possibility of gene transfer from transgenic plant into soil microorganisms. In our present study, we have assessed the effects of herbicide-resistant GM Chinese cabbage on the surrounding soil microbial community. METHODS AND RESULTS: The effects of a herbicide-resistant genetically modified (GM) Chinese cabbage on the soil microbial community in its field of growth were assessed using a conventional culture technique and also culture-independent molecular methods. Three replicate field plots were planted with a single GM and four non-GM Chinese cabbages (these included a non-GM counterpart). The soils around these plants were compared using colony counting, denaturing gradient gel electrophoresis and a species diversity index assessment during the growing periods. The bacterial, fungal and actinomycetes population densities of the GM Chinese cabbage soils were found to be within the range of those of the non-GM Chinese cabbage soils. The DGGE banding patterns of the GM and non-GM soils were also similar, suggesting that the bacterial community structures were stable within a given month and were unaffected by the presence of a GM plant. The similarities of the bacterial species diversity indices were consistent with this finding. CONCLUSION: These results indicate that soil microbial communities are unaffected by the cultivation of herbicide-resistant GM Chinese cabbage within the experimental time frame.

• 한국균학회소식:학술대회논문집
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• 2014.10a
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• pp.41-41
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• 2014

Agaricus bisporus, commonly known as the button mushroom, is the most widely cultivated species of edible fungi. Low frequency of recombination ratio and homokaryotic or monokaryotic spore on meiotic basidia form obstacles for breeding programs. Since the first hybrid varieties for white button mushrooms were released in Europe, new varieties released afterwards were either identical of very similar to these first hybrids on morphologies. Therefore, different DNA markers have been used to define unique varieties of A. bisporus strains. Aim of this study is to assess the genetic diversity of different A. bisporus strains in Korea. Twelve UFP (Universal fungal primer, JK BioTech. Ltd), 12 simple sequence repeat (ISSR) and 30 SSR primers were used to assess genetic diversity of monokaryotic and dikaryotic Agaricus bisporus strains including other 19 Agaricus spp. Of them, four UFP, four SSR primers, $(GA)_8T$, $(AG)_8YC$, $(GA)_8C$ and $(CTC)_6$ and seven SSR markers produced PCR polymorphic bands between the Agaricus species or within A. bisporus strains. PCR polymorphic bands were inputted for UPGMA cluster analysis. Forty five strains of A. bisporus are genetically clustered into 6 groups, showing coefficient similarity from 0.75 to 0.9 among them. In addition, genetic variations of monokaryotic and dikaryotic Agaricus bisporus strains were partially detected by PCR technologies of this study. The varieties, Saea, saedo, Saejeong and Saeyeon that have recently been developed in Korea were involved in the same group with closely genetic relationship of coefficient similarity over 0.96, whereas, other strains were genetically related to A. bisporus strains that were introduced from USA, Eroupe and Chinese.

• Journal of Crop Science and Biotechnology
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• v.11 no.3
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• pp.205-214
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• 2008

Blast disease caused by the fungal pathogen, Magnaporthe oryzae, is one of the most damaging diseases in rice. The use of resistant varieties is an effective measure to control the disease, however, many resistant varieties were broken down to their resistance effects by the differentiating of new virulent isolates. This study was done to analyze the haplotypes of 31 microsatellite markers linked to five major R genes and two QTLs and to identify the alleles for the putatively novel genes related to durable resistance to blast in 56 Korean japonica and four indica varieties. The 31 microsatellite markers produced 2 to 13 alleles(mean = 5.4) and had PICi values ranging from 0.065 to 0.860(mean=0.563) among the 60 rice accessions. Cluster analysis based on allele diversities of 31 microsatellite markers grouped into 60 haplotypes and ten major clusters in 0.810 genetic similarity. A subcluster IV-1 grouped of early flowering varieties harboring Piz and/or Pi9(t) on chromosome 6 and Pita/Pita-2 gene on chromosome 12. The other subcluster V-1 consisted of four stable resistance varieties Donghae, Seomjin, Palgong and Milyang20. The analysis of putative QTLs associated with seven blast resistance genes using ANOVA and linear regression showed high significance to blast resistance across regions and isolates in the markers of two genes Piz and/or Pi9(t) and Pita/Pita-2. These results illustrate the utility of microsatellite markers to identify rice varieties is likely carrying the same R genes and QTLs and rice lines with potentially novel resistant gene.

• The Korean Journal of Mycology
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• v.47 no.3
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• pp.199-208
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• 2019

In this study, the community structures of the ectomycorrhizal (ECM) fungi in the roots of Abies koreana and Taxus cuspidata were investigated at different altitudes of Mt. Halla. We identified the collected ECM root tips based on morphological characteristics and phylogenetic analysis through sequencing of the rDNA ITS regions. From the roots of A. koreana and T. cuspidata, 11 species and 12 species were identified, respectively. The Shannon's index and species evenness and abundance of the ECM fungi were higher in the higher than lower regions, regardless of host plant species, however, the number of ECM root tips showed the opposite pattern. The community similarity among the ECM fungi in A. koreana was significantly higher than that among the ECM fungi in T. cuspidata or than that between A. koreana and T. cuspidata (p < 0.05). These results could be useful for the conservation and management of the habitat of A. koreana, which is threatened with extinction due to increasing ambient air temperature.

• Journal of Ginseng Research
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• v.43 no.1
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• pp.77-85
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• 2019

Background: Glomus intraradices is a species of arbuscular mycorrhizal fungi that, as an obligate endomycorrhiza, can form mutually beneficial associations with plants. Panax ginseng is a popular traditional Chinese medicine; however, problems associated with ginseng planting, such as pesticide residues, reduce the ginseng quality. Methods: In this experiment, we studied the effect of inoculating G. intraradices on several physiological properties and microbial communities of ginseng. UV-Visible Spectrum method was used to detect physical properties. Denaturing gradient gel electrophoresis method was used to analyze microbial communities. Results: The results indicated that inoculation with G. intraradices can improve the colonization rate of lateral ginseng roots, increase the levels of monomeric and total ginsenosides, and improve root activity as well as polyphenol oxidase and catalase activities. We also studied the bacterial and fungal communities in ginseng rhizospheric soil. In our study, G. intraradices inoculation improved the abundance and Shannon diversity of bacteria, whereas fungi showed a reciprocal effect. Furthermore, we found that G. intraradices inoculation might increase some beneficial bacterial species and decreased pathogenic fungi in rhizospheric soil of ginseng. Conclusion: Our results showed that G. intraradices can benefit ginseng planting which may have some instructive and practical significance for planting ginseng in farmland.

• Korean Journal of Organic Agriculture
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• v.31 no.1
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• pp.95-106
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• 2023

Entomopathogenic fungi are one of the microorganisms distributed worldwide, and they inhabit not only insects but also soils of various regions such as agricultural land and forest areas. In this study, entomopathogenic fungi distributed in the soil of forest areas in Korea were isolated using the insect-baiting method, and the relationship between the distribution and diversity of entomopathogenic fungi and the physical/chemical characteristics of the soil was analyzed. The soils were collected from five forest areas in Korea, and a total of 42 entomopathogenic fungal isolates were isolated from the collected soils. Among them, Beauveria bassiana (42.9%) and Metarhizium anisopliae (45.2%) were mainly isolated. In particular, it was confirmed that the distribution of M. anisopliae varies depending on the total nitrogen (g/kg) and organic matter content (%) of the soil. The soils in forest areas in Korea have a low pH of 4-5. Among all isolates, >50% of entomopathogenic fungi were isolated from silt loam. This study suggests that it will be helpful in understanding the relationship between the distribution and diversity of entomopathogenic fungi and the physical and chemical characteristics of soil.

• Journal of Environmental Science International
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• v.33 no.1
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• pp.27-41
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• 2024

In this study, we evaluated productivity, soil physiochemical properties, and soil microbial characteristics in Kimchi cabbage(Brassica rapa subsp. pekinensis) cultivation within a highland environment during summer. Specifically, we examined the effect of different cropping systems, namely monoculture and rotation with soybean, over an 8-year cropping period. The results of our investigation revealed that significant differences were absent in terms of yield and soil physiochemical properties between the two cropping systems. However, microbial characteristics exhibited distinctive patterns. Bacterial diversity was significantly higher in the rotation system that in the monoculture, whereas fungal diversity demonstrated a preference for rotation although the result was not significant. Our findings identified the presence of Bradyrhizobium stylosanthis, a nitrogen-fixation symbiont, as an indicator ASV (amplicon sequence variant) in the rotation system, where it displayed significantly higher abundances. These observations suggest a potential positive effect of the rotation system on nitrogen fixation. Notably, throughout the cultivation period, both cropping systems did not exhibit critical disease incidences. However, Fusarium oxysporum, a well-known pathogen responsible for inducing fusarium wilt disease in Kimchi cabbage, was detected with significantly higher abundance in the monoculture system. This finding raises concerns about the potential risk associated with Kimchi cabbage cultivation in a long-term monoculture system.

• The Korean Journal of Mycology
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• v.24 no.1 s.76
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• pp.56-66
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• 1996

Ecological variations of Arbuscular mycorrhizal (AM) fungi were determined from the soils collected from different sites of the polluted and unpolluted areas related to the soil pollutions. Average 24.5 spores $(per\;20g)^{-1}$ soil of AM fungal spore were counted from the 32 sites of soils collected from On-san (polluted), whereas average 4.1 spores $(per\;20g)^{-1}$ soil from the 18 sites of those from Mt. Kwanak (polluted); Average 23.6 spores $(per\;20g)^{-1}$ soil of AM fungal spore were also counted from the 30 sites of soils collected from Chung-mu (unpolluted), whereas average 15.8 spores $(per\;20g)^{-1}$ soil from the 14 sites of those from Mt. Chungwang (unpolluted).The spores of AM fungi were the species of Glomus, Gigaspora, Acaulospora and Scutellospora. Among the above four genera, the species of Glomus were observed to be more abundant than the other genera in the soils collected from On-san, Chung-mu and Mt. Chungwang whereas the species of Gigaspora in those from Mt. Kwan-ak. The parameters of soils measured showed some variations between the polluted and unpolluted areas; 12.9 to 16.4% in the soil moisture, 5.6 to 8.3% in the organic matter and 4.3 to 5.7 at soil pH (polluted to unpolluted areas, respectively). The soils collected, thereby, appeared to be more strongly acidic and also lower in the contents of soil moisture or organic matter at the polluted area than unpolluted area. Based on the ecological criteria, the species richness or species diversity had significant differences (p<0.05) between polluted and unpolluted area. The spore density of genus Glomus or Gigaspora was significantly different (p<0.05) among the soils of three different plant vegetations (conifer plants, broad leaf plants, and grass plants). Also, there were significant differences (p<0.05) in the species evenness or species diversity among the soils referring to three different plant vegetations. There was a direct relationship $(r^2=0.38)$ between soil moisture and organic matter measured from 94 soil samples. Since there was a direct relationship $(r^2=0.22)$ between organic matter and total spores, it seems to be likely to presume that mycorrhizal spores can be increased in proportion to enhanced organic matters in soils. The species richness or species diversity was inclined to increase in proportion to enhanced soil pH and total spores in soils.