• The Plant Pathology Journal
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• v.28 no.2
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• pp.156-163
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• 2012

Stem rots caused by Rhizoctonia solani and Sclerotinia sclerotiorum have been known as devastating diseases in balloon flower plants. Antifungal activities of four fungicides, azoxystrobin, polyoxin B, trifloxystrobin and validamycin A were evaluated in vitro, showing effective suppression with mycelial growth of the fungal isolates on PDA media. Efficacies of the four fungicides were also demonstrated in stem tissues of balloon flower plants against R. solani and S. sclerotiorum. A commercially available Bacillus subtilis strain Y1336 was tested in terms of antagonistic biological control of stem rot disease of balloon flower plants. The bacterial strain revealed its antifungal activities against R. solani and S. sclerotiorum demonstrated by dual culture tests using paper discs and two plant pathogenic fungi on PDA media, as well as by plant inoculation assay, indicating that this antagonistic bacterial strain can be incorporated into disease management program for balloon flower stem rot diseases together with the four chemical fungicides.

• The Plant Pathology Journal
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• v.18 no.6
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• pp.301-307
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• 2002

Graft transmission and cytopathological studies of a severe pear disease, pear black necrotic leafspot（PBNLS), were carried out to determine the causal agent of the disease. No evidence was found that a fungal or bacterial pathogen could be the causal agent of the disease. Attempts to transmit the agent by sap-inoculation to other plants including herbaceous hosts failed. How-ever, the pathogen was readily graft-transmitted from symptomatic diseased pears to healthy pears. Graft transmission of the pathogen was also demonstrated by using an indicator plant, PS-95, developed in the laboratory through various grafting methods. Ultrastructural study of the disease revealed the consistent presence of flexuous rod-shaped virus-like particles (VLP) in the symptomatic leaves of both Niitaka cultivar and indicator pear, PS-95. The particles, approximately 12 nm in diameter with undetermined length, occurred in the cytoplasm of mesophyll parenchyma cells. Cells with VLPs also contained fibril-containing vesicles, which are common in cells infected with plant viruses with ssRNA genome. The vesicles were formed at the tonoplast. Based on the symptomatology, the presence of fibril-containing vesicles, and graft-transmissibility, it is believed that the VLPs that occurred on symptomatic leaves of black necrotic leafspot of pear are viral in nature, possibly those of a capillovirus.

• The Korean Journal of Mycology
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• v.49 no.4
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• pp.441-454
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• 2021

Fungal diseases including anthracnose, stem rot, blight, wilting, and root rot of crops are caused by phytopathogens such as Colletotrichum species, Sclerotinia sclerotiorum, Phytophthora species, and Fusarium oxysporum and F. solani which threaten the production of chili pepper. In this study, to identify biological control agents (BCAs) of phytopathogenic fungi, potentially useful Bacillus species were isolated from the field soils. We screened out five Bacillus strains with antagonistic capacity that are efficiently inhibiting the growth of phytopathogenic fungi. Bacillus species were characterized by the production of extracellular enzymes, siderophores, and indole-3-acetic acid (IAA). Furthermore, the influence of bacterial strains on the plant growth promoting activity and seedling vigor index were assessed using Brassica juncea as a model plant. Inoculation with Bacillus subtilis SRCM 121379 significantly increased the length of B. juncea shoots and roots by 45.6% and 52.0%, respectively. Among the bacterial isolates, Bacillus subtilis SRCM 121379 showed the superior enzyme activities, antagonistic capacity and plant growth promoting effects. Based on the experimental results, Bacillus subtilis SRCM 121379 (GenBank accession no. NR027552) was finally selected as a BCA candidate.

• Journal of Ginseng Research
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• v.43 no.3
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• pp.408-420
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• 2019

Background: Ginseng (Panax ginseng Meyer) is an invaluable medicinal plant containing various bioactive metabolites (e.g., ginsenosides). Owing to its long cultivation period, ginseng is vulnerable to various biotic constraints. Biological control using endophytes is an important alternative to chemical control. Methods: In this study, endophytic Trichoderma citrinoviride PG87, isolated from mountain-cultivated ginseng, was evaluated for biocontrol activity against six major ginseng pathogens. T. citrinoviride exhibited antagonistic activity with mycoparasitism against all ginseng pathogens, with high endo-1,4-${\beta}$-D-glucanase activity. Results: T. citrinoviride inoculation significantly reduced the disease symptoms caused by Botrytis cinerea and Cylindrocarpon destructans and induced ginsenoside biosynthesis in ginseng plants. T. citrinoviride was formulated as dustable powder and granules. The formulated agents also exhibited significant biocontrol activity and induced ginsenosides production in the controlled environment and mountain area. Conclusion: Our results revealed that T. citrinoviride has great potential as a biological control agent and elicitor of ginsenoside production.

• Archives of Plastic Surgery
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• v.48 no.2
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• pp.231-236
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• 2021

Mucormycosis is an invasive, rapidly progressive, life-threatening fungal infection, with a propensity for diabetic, immunosuppressed, and trauma patients. The classic rhinocerebral variation is most common in diabetic patients. While the cutaneous form is usually caused by direct inoculation in immunocompetent patients. Cutaneous mucormycosis manifests in soft tissue and risks involvement of underlying structures. Tibial osteomyelitis can also occur secondary to cutaneous mucormycosis but is rare. Limb salvage is typically successful after lower extremity cutaneous mucormycosis even when the bone is involved. Herein, we report two cases of lower extremity cutaneous mucormycosis in diabetic patients that presented as acute worsening of chronic pretibial ulcers. Despite aggressive antifungal therapy and surgical debridement, both ultimately required amputation. Such aggressive presentation has not been reported in the absence of major penetrating trauma, recent surgery, or burns.

• The Plant Pathology Journal
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• v.39 no.2
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• pp.181-190
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• 2023

The fungal pathogen Pseudocercospora fuligena, known to affect tomatoes in the tropics and subtropics, has been reported from temperate climates including the United States and Turkey in recent years. In this study, an isolate from fresh tomatoes and the disease it causes were characterized and infection mechanisms investigated. Macroscopically, both sides of tomato leaves show indistinct effuse patches but prolific production of fuliginous lesions is conspicuous on the abaxial side first but also on the adaxial side later on as infection progressed. Microscopically, fascicles of conidiophores (11-128 ㎛ × 3.5-9 ㎛) arising from stromata and conidia with up to 12 septations were observed. Molecular characterization of the isolate revealed high homology (99.8%) to other P. fuligena isolated from tomatoes in Turkey. Out of the 10 media tested, P. fuligena grew significantly well and sporulated better on unsealed tomato oatmeal agar and carrot leaf decoction agar, both supplemented with CaCO₃. Direct transfer of conidia from profusely sporulating lesions was the easiest and quickest method of isolation for in-vitro studies. Light and scanning electron microscopy on cleared and intact tomato leaves further confirmed stomatal penetration and egress as well as prevalence of primary and secondary infection hyphae. In situ, blocked stomatal aperture areas of 154, 401, and 2,043 ㎛² were recorded at 7, 12, and 17 days after inoculation, respectively. With the recent expanded horizon of the pathosystem and its consequential impact, such studies will be useful for a proper diagnosis, identification and management of the disease on tomato worldwide.

• Research in Plant Disease
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• v.22 no.3
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• pp.152-157
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• 2016

Root-dipping inoculation method has been used to investigate resistance of radish plants to Fusarium wilt. However, the method requires a lot of labor and time because of complicate procedure. This study was conducted to establish a simple and effective mass-screening method for resistant radish to Fusarium wilt. Radish seedlings of susceptible and resistant cultivars were used to investigate wounding method by scalpel, inoculum concentration, and pathogen-inoculated growth stage of seedlings. We established an efficient mass-screening method based on our results as following: Roots of 14-day-old seedlings of radish are cut with a scalpel at a $90^{\circ}$ angle to a 2 cm-depth at a 1 cm-distance from main stem and then inoculated by pouring with a 10 ml-aliquot of a fungal spore suspension ($1.0{\times}10^7conidia/ml$) on soil. The inoculated plants are cultivated in a growth room at $25^{\circ}C$ for about 4 weeks with 12-hour light a day. The proposed screening method enables to effectively select resistant from mass radish plants cultivars to Fusarium wilt.

• Korean Journal of Environmental Agriculture
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• v.20 no.1
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• pp.50-56
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• 2001

Thirty-three bacterial and fungal strains were isolated from the rotten soybeans and soybean sprouts to isolate pathogenic microorganisms which cause soybean sprouts rot during soybean sprouts cultivation. In pathogenicity tests of the isolates on soybean sprouts, two isolates(K-17 and K-28) caused soybean sprouts rot and were identified as Erwinia carotovora and Fusarium sp., respectively. To isolate antagonists aganist K-17 and K-28 pathogens, bacteria were isolated from various soybean-cultivated soils and screened by the inhibition zone method. A bacterial isolate(J-232) which inhibited growth of both pathogens was identified as Pseudomonas fluorescens and further examined. The culture filtrate of P. fluorescens J-232 (dilution rate of 500 times) inhibited the growth of Erwinia carotovora K-17 and Fusarium sp. K-28 both on potato dextrose agar medium and on soybean sprouts cultivated in vessel. The development of soybean sprouts rots was observed during cultivation by inoculation of soybean seeds with culture filtrate of both pathogens. The combined inoculation of soybean seeds with culture filtrate of antagonistic bacterium and that of pathogens prevented soybean sprouts rot, and the growth of soybean sprouts was similar to that of control. The soybean sprouts inoculated with antagonists culture filtrate alone did not develop soybean sprouts rot, and the growth of the seedlings was shown to be slightly promoted as compared with that of control.

• The Korean Journal of Mycology
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• v.31 no.1
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• pp.1-7
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• 2003

One hundred fifty one specimens of Beauveria spp. from 19 different locations were collected from September 1 to August 31, 2002. Most of the isolates were identified as Beauveria. bassiana. Cordyceps staphylinidaecola collected from Mt. Obong in Chunchon City covered the host with mycelia which were produced 1 to 4 stromata along with asexual spores. The size of bright yellow ununiform stromata were about 45 mm and the head about $17mm{\times}4mm$. Perithecia completely immersed were $530{\sim}550{\times}290{\sim}300{\mu}m$ in size and mainly scattered on the head. Ascospore produced in asci in the size of $400{\sim}450{\times}4{\sim}5{\mu}m$ developed thread-like secondary spores, which were directly separated into secondary conidial spores. Conidia produced at apical portion of synnemata were $2.6{\sim}3.4{\times}1.2{\sim}1.9{\mu}m$ in size. High density of mycelium was observed at $25^{\circ}C$ ranged from pH 6.5 to 8.5 after 11 days of inoculation. It took 15 to 18 days after inoculation to fully grow on the medium mixed brown rice with pupa. Mycelium developed stromata on the medium 30 days after completion of mycelial growth, where perithecia were produced in 40 days.

• Journal of Korean Society of Forest Science
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• v.81 no.2
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• pp.156-163
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• 1992

Pinus koraiensis (Pk), P. rigida (Pr) and P. rigida ${\times}$ P. taeda (Pr. t) seedlings in a bare-rooted nursery were artificially inoculated with Pisolithus tinctorius (Pt) and Thelephora terrestris (Tt) to test long term effects of ectomycorrhizal inoculation on host growth. Mycelial inocula of Pt and Tt were mass-cultured in vermiculite-peatmoss mixture and introduced into fumigated nursery soil before seed sowing. Bare-rooted, inoculated seedlings at one to four years of age were outplanted to the field with $P_2O_5$ content of 25 ppm in soil. At the time of outplanting, Pk seedlings(4 years old), Pr seedlings(2 years old), and Pr.t seedlings(1 year old) all infected by Pt were significantly taller by 28%. 26%, and 77%, respectively, than controlled seedlings infected by natural population of mycorrhizal fungi in the non-fumigated plot. Ten years after inoculation or six to nine years after outplanting, Pk seedlings inoculated with Pt were significantly taller by 9% Pr.t seedlings significantly taller by 18%, and Pr slightly Caller by 2%(not significant) than controlled seedlings, suggesting that the stimulatory effect of Pt on host growth gradually declined or became minimal after outplanting. Tt failed to stimulate host growth either in the nursery or in the field, and the survival rate of outplanted seedlings was not different among fungal treatments. Considerable loss of the infected root system during lifting the seedlings for outplanting would be the primary cause of the reduced effect of Pt in the field. Pt infected more than 90% of the fine roots in the fumigated nursery during the first growing season, but Pt assumed to fail to compete successfully with natural population of ectomycorrhizal fungi in the field. It is necessary to select other mycorrhizal fungi which adapt well in both nursery and field.