• The Plant Pathology Journal
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• v.27 no.2
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• pp.138-147
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• 2011

Xylogone ganodermophthora, an ascomycetous fungus, is known to cause yellow rot in the cultivated mushroom Ganoderma lucidum. In this study, we investigated the dissemination of this fungal pathogen in G. lucidum grown in cultivation houses. To determine the role of ascospores produced by X. ganodermophthora in disease development, we constructed a green fluorescent protein-labeled transgenic strain. This X. ganodermophthora strain produced a number of ascomata in the tissues of oak logs on which G. lucidum had been grown and on the mushroom fruit bodies. However, the ascospores released from the ascomata were not able to germinate on water agar or potato dextrose agar. Moreover, less than 0.1% of the ascospores showed green fluorescence, indicating that most ascospores of X. ganodermophthora were not viable. To determine the manner in which X. ganodermophthora disseminates, diseased oak logs were either buried in isolated soil beds as soil-borne inocula or placed around soil beds as air-borne inocula. In addition, culture bottles in which G. lucidum mycelia had been grown were placed on each floor of a five-floor shelf near X. ganodermophthora inocula. One year after cultivation, yellow rot occurred in almost all of the oak logs in the soil beds, including those in beds without soil-borne inocula. In contrast, none of the G. lucidum in the culture bottles was infected, suggesting that dissemination of X. ganodermophthora can occur via the cultivation soil.

• Mycobiology
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• v.48 no.4
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• pp.326-329
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• 2020

Valuable natural compounds produced by a variety of microorganisms can be used as lead molecules for development of new agrochemicals. Furthermore, high-throughput in vitro screening systems with specific modes of action can increase the probability of discovery of new fungicides. In the current study, a rapid assay tested with various microbes was developed to determine the degree of respiratory inhibition of Saccharomyces cerevisiae in two different liquid media, YG (containing a fermentable carbon source) and NFYG (containing a non-fermentable carbon source). Based on this system, we screened 100 fungal isolates that were classified into basidiomycetes, to find microbial secondary metabolites that act as respiratory inhibitors. Consequently, of the 100 fungal species tested, the culture broth of an IUM04881 isolate inhibited growth of S. cerevisiae in NFYG medium, but not in YG medium. The result is comparable to that from treatment with kresoxim-methyl used as a control, suggesting that the culture broth of IUM04881 isolate might contain active compounds showing the inhibition activity for respiratory chain. Based on the assay developed in this study and spectroscopic analysis, we isolated and identified an antifungal compound (-)-oudemansin A from culture broth of IUM04881 that is identified as Oudemansiella venosolamellata. This is the first report that (-)-oudemansin A is identified from O. venosolamellata in Korea. Taken together, the development of this assay will accelerate efforts to find and identify natural respiratory inhibitors from various microbes.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.12
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• pp.1890-1896
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• 2018

Objective: As the climate changes, it influences ruminant's feed intake, nutrient digestibility, rumen methane production and emission. This experiment aimed to evaluate the effect of feeding Sweet grass (Pennisetum purpureum cv. Mahasarakham; SG) as a new source of good quality forage to improve feed utilization efficiency and to mitigate rumen methane production and emission. Methods: Four, growing crossbred of Holstein Friesian heifers, 14 months old, were arranged in a $4{\times}4$ Latin square design to receive four dietary treatments. Treatment 1 (T1) was rice straw (RS) fed on ad libitum with 1.0% body weight (BW) of concentrate (C) supplementation (RS/1.0C). Treatment 2 (T2) and treatment 3 (T3) were SG, fed on ad libitum with 1.0% and 0.5% BW of concentrate supplementation, respectively (SG/1.0C and SG/0.5C, respectively). Treatment 4 (T4) was total Sweet grass fed on ad libitum basis with non-concentrate supplementation (TSG). Results: The results revealed that roughage and total feed intake were increased with SG when compared to RS (p<0.01) while TSG was like RS/1.0C treatment. Digestibility of nutrients, nutrients intake, total volatile fatty acids (VFAs), rumen microorganisms were the highest and CH4 was the lowest in the heifers that received SG/1.0C (p<0.01). Total dry matter (DM) feed intake, digestibility and intake of nutrients, total VFAs, $NH_3-N$, bacterial and fungal population of animals receiving SG/0.5C were higher than those fed on RS/1.0C. Reducing of concentrate supplementation with SG as a roughage source increased $NH_3-N$, acetic acid, and fungal populations, but it decreased propionic acid and protozoal populations (p<0.05). However, ruminal pH and blood urea nitrogen were not affected by the dietary treatments (p>0.05). Conclusion: As the results, SG could be a good forage to improve rumen fermentation, decrease methane production and reduced the level of concentrate supplementation for growing ruminants in the tropics especially under global climate change.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.10
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• pp.1548-1557
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• 2019

Objective: To investigate the effects of dietary supplementation with different levels and molecular weights of fungal ${\beta}$-glucan on productive performances, health, carcass traits and meat quality in broilers. Methods: Two hundred and ten of one-day-old chicks with equal sex were assigned to seven experimental groups in $2{\times}4$ factorial arrangement. These groups were supplemented with (0, 10, 30, and 60 ppm) of molecular weight 1-3, 1-6 ${\beta}$-glucan (low or high). High molecular weight ${\beta}$-glucan (H: 943 kDa) was obtained from Ophiocordyceps dipterigena BCC 2073, whereas H with ${\gamma}$-Irradiation treatment was performed to achieve low molecular weight ${\beta}$-glucan (L: 8 kDa). Results: There was no statistical significance in productive performances, apparent digestibility and interaction between fixed factors along 42 days of experiment (p>0.05). A higher caecal amylase activity was present in the group that received L, while there was a dramatic decrease in H and the control groups, respectively (p<0.05). The increase of supplemental dose increased caecal amylase activity (p<0.05). Immunomodulatory effects from L was revealed by the marked increase of phagocytic activity, relative weight of thymus and bursa of fabricius (p<0.05). Similarly, the additive dose at 30 ppm provided the same results, whereas the only significant difference with supplementation at 60 ppm was an increase in phagocytic activity (p<0.05). Interestingly, villi height of broilers fed L was higher than other groups (p<0.05). The treatments did not influence haematology, blood chemistry, antibody production level against vaccination, carcass traits and meat quality (p>0.05). Conclusion: The supplementation of L at 30 ppm was suggested to achieve benefits of immune modulation without adverse effects on other parameters.

• Mycobiology
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• v.51 no.4
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• pp.264-272
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• 2023

Onion (Allium cepa L.) is an economically important vegetable crop worldwide. However, various fungal diseases, including Fusarium basal rot (FBR), neck rot, and white rot, reduce onion production or bulb storage life. FBR caused by Fusarium species is among the most destructive onion diseases. In this study, we identified Fusarium species associated with FBR in Jeolla and Gyeongsang Provinces in South Korea and evaluated fungicides against the pathogens. Our morphological and molecular analyses showed that FBR in onions is associated with Fusarium commune, Fusarium oxysporum, and Fusarium proliferatum. We selected seven fungicides (fludioxonil, hexaconazole, mandestrobin, penthiopyrad, prochloraz-manganese, pydiflumetofen, and tebuconazole) and evaluated their inhibitory effects on mycelial growth of the pathogens at three different concentrations (0.01, 0.1, and 1 mg/mL). We found that prochloraz-manganese was highly effective, inhibiting 100% of the mycelial growth of the pathogens at all concentrations, followed by tebuconazole. Fludioxonil showed < 50% inhibition at 1 mg/mL for the tested isolates.

• Korean Journal of Food Science and Technology
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• v.23 no.5
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• pp.614-618
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• 1991

To investigate the efficacy of grapefruit seed extract (GFSE) in the preservation of Satsuma mandarin, the citrus fruits were treated with 0 (control, only wash), 100 ppm and 250 ppm, dried and stored for 8 weeks at $15{\sim}20^{\circ}C$ and 60% RH. While 80% of the control fruits were contaminated and decayed by Penicillium sp., forming the the greenish blue spores, 27% of 100 ppm GFSE-treated fruits were contaminated and decayed and only 13% of 250 ppm GFSE-treated fruits were contaminated and decayed and only 13% of 250 ppm GFSE-treated samples were contaminated and not decayed by the fungi. GFSE showed marded inhibitory action against Penicillium sp. which was related to the decay of the citrus fruits in vitro experiments. Fungal growth was completely controlled through use of 500 ppm and the recommended range of GFSE to preserve the citrus fruits was $250{\sim}500ppm$. Transmission electron microscopic examination showed the fungal conidiospores the function of which was destroyed by dipping into GFSE.

• Mycobiology
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• v.38 no.1
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• pp.78-80
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• 2010

Leaf spot symptoms were frequently observed on yam plants grown in the Yeoju area in Korea during a disease survey in 2008. A total of five isolates of Pseudophloeosporella sp. were obtained from the infected leaves of yam plants. All of the isolates were identified as Pseudophloeosporella dioscoreae based on their morphological and cultural characteristics. A phylogenetic tree derived from the internal transcribed spacer sequences of the fungal isolates showed that the fungus is distinctly separated from species in other related genera. P. dioscoreae isolates caused very tiny spots on leaves of yam plants two weeks after artificial inoculation which were similar to those observed in the field. This is the first report that Pseudophloeosporella dioscoreae causes leaf spot in yams in Korea.

• Mycobiology
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• v.46 no.2
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• pp.147-153
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• 2018

Certain beneficial microorganisms isolated from rhizosphere soil promote plant growth and induce resistance to a wide variety of plant pathogens. We obtained 49 fungal isolates from the rhizosphere soil of paprika plants, and selected 18 of these isolates that did not inhibit tomato seed germination for further investigation. Based on a seed germination assay, we selected four isolates for further plant tests. Treatment of seeds with isolate JF27 promoted plant growth in pot tests, and suppressed bacterial speck disease caused by Pseudomonas syringae pathovar (pv.) tomato DC3000. Furthermore, expression of the pathogenesis-related 1 (PR1) gene was higher in the leaves of tomato plants grown from seeds treated with JF27; expression remained at a consistently higher level than in the control plants for 12 h after pathogen infection. The phylogenetic analysis of a partial internal transcribed spacer sequence and the b-tubulin gene identified isolate JF27 as Aspergillus terreus. Taken together, these results suggest that A. terreus JF27 has potential as a growth promoter and could be used to control bacterial speck disease by inducing resistance in tomato plants.

• The Plant Pathology Journal
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• v.25 no.3
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• pp.294-298
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• 2009

Stem canker symptoms were observed in a rape field in Muan, Korea during a disease survey in May 2006. A total of 15 isolates of Phoma sp. were obtained from the infected stems of the plant. All isolates were identified as Leptosphaeria biglobosa based on their morphological and cultural characteristics. The Korean isolates of L. biglobosa were assigned to 'brassicae' among six subclades of L. biglobosa complex based on the entire ITS sequences of rDNA. Pathogenicity of the fungal isolates was confirmed on leaves and stems of rape by artificial inoculation. This is the first report that Leptosphaeria biglobosa causes stem canker of rape in Korea.

• 한국균학회소식:학술대회논문집
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• 2018.05a
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• pp.51-51
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• 2018

The application of recombinant DNA technology has been remarkable and nearly replaced commonly used traditional methods. Traditional industrial microbiology long depended on the discovery of valuable strains and mutagenesis of such strains to improve its secretion capacity of enzymes and secondary metabolites on the industrial scale. Commodities included industrial enzymes and biopharmaceuticals. The purpose of genome manipulation by the crossing of different strains or genetic recombination of naked DNA to the genome is of increased production of valuable metabolites. We optimized a transformation method to either for removal of innate genes, introduction of heterologous genes, or combination of both. We have been used selected whole or partial genes to manipulate target fungi toward the development of strains overproducing invaluable proteins. We have also used the whole genome sequence information of fungal genomes in public databases and functional genomics approach to select genes to manipulate and eventually contributing greatly to the development of overproducing industrial strains overproducing proteins or secondary metabolites. I will briefly review 1) filamentous fungi as a host for production of recombinant proteins and secondary metabolites, 2) markets of industrial metabolites, 3) a new approach to manipulate up to five genes at the same time in the system that ProxEnrem uses.