• The Korean Journal of Pesticide Science
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• v.13 no.4
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• pp.332-335
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• 2009

Rhizo-bacteria were isolated from organic-farming soils to select antagonistic agent for controlling citrus melanose disease. Among several antagonistic bacteria, KB-401 effectively inhibited mycelial growth of several plant fungal pathogens, including the pathogen of citrus melanose, Diaporthe citri. KB-401 also inhibited spore germination of the fungal pathogen. The tip of germ tube was swollen when conidia of D. citri were co-culture with KB-401 in PD broth amended 1% glucose. KB-401 was identified as Bacillus subtilis through the investigation for physiological characters and the analysis of nucleotide sequences of 16S rDNA.

• YAKHAK HOEJI
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• v.38 no.2
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• pp.158-165
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• 1994

A protein-polysaccaride fraction Kp(53.9% polysaccharide, 14.2% protein) was separated from the shake-cultured mycelia of a basidiomycetous fungus, Phellinus linteus, and its antitumor activity against sarcoma 180 in ICR mice was investigated. When administered after the tumor implantation, Kp exerted antitumor activity by inhibiting the growth of the sarcoma 180 solid tumor by 71.5% and increasing the life span of the sarcoma 180 ascitic mice by 51.5% at 100 mg/kg. In pretreatment tests, in which Kp was administered once daily for 9 days before the tumor implantation, Kp inhibited the growth of the solid and ascites form of sarcoma 180, respectively, by 35.4% and by 80.3% at 100 mg/kg. However, Kp showed no in vitro cytotoxic activity against a murine leukemia L1210 and a human gastric tumor SNU.1 upto the concentration of $200\;{\mu}g/ml$. From these results, it is clear that the antitumor activity of Kp is exerted through its immunomodulating activity on the host's immune system.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2003.10b
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• pp.47-47
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• 2003

Plant growth promoting rhizobacteria (PGPR) have been shown to suppress phytopthora blight. This suppression has been related to both microbial antagonism and induced resistance. The PGPR isolates were screened by dual culture plate method and most of the isolates were showed varyinglevels of antagonism. Among the PGPR isolates pyoverdin, pyochelin and salicylic acid producing strains showed the maximum inhibition of mycelial growth of Phytophthora capsici and increased plant growth promotion in red pepper. PGPR isolatesfurther analysed for its ability to induce production of defence related enzymes and chemicals. The activities such as Phenyle alanin ammonia lyase (PAL), Peroxidase (PO), Polyphenol oxidase (PPO) and accumulation of phenolics were observed in PGPR pretreated red pepper plants challenged with Phytophthora capsici. The present study shows that an addition of direct antagonism and plant growth promotion, induction of defense related enzymes involved to enhance resistance against invasion of P. capsici in red pepper.

• KSBB Journal
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• v.26 no.1
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• pp.33-40
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• 2011

Anti-diabetic effect of the exopolysaccharides (EPS) produced from submerged mycelial culture of Cordyceps sinensis (Cs) was studiedin a type II diabetic animal model (C57BL/6J ob/ob). This study was designed to determine whether Cs-EPS improves clinical symptoms of type II diabetes in ob/ob mice. After Cs-EPS treatment at doses of 200 mg/kg body weight, the fasting blood glucose levels decreased by 47% after 7 weeks compared with those of the control mice. According to the oral glucose tolerance test, the glucose levels recovered its baseline after 120 min in Cs-EPS-treated mice, although the blood glucose levels increased significantly after 30 min. On the other hand, the control group (not-treated) did not recovered its initial level of glucose after 120 min. Furthermore, food intake, body weight, total plasma cholesterol and triglyceride concentrations in ob/ob mice treated with Cs-EPS were significantly decreased, compared with those in control ob/ob mice. Cs-EPS treatment increased significantly the plasma insulin level and the expression of leptin mRNA in adipose tissue of Cs-EPS-treated ob/ob mice. From these results, it is demonstrated that Cs-EPS could be effective for regulating normal blood glucose levels by increasing the amounts of plasma insulin and leptin expression in ob/ob mice, indicating that this compound could be a candidate material as a dietary supplement to control hyperglycemia in patients suffering from type II diabetes.

• Korean Journal Plant Pathology
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• v.14 no.3
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• pp.268-277
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• 1998

The production of Korean ginseng, one of the most important medicinal root crops, is limited by many factors including soil sickness, root rots in fields as well as during storage prior to consumption. Although much research has been conducted on the diseases in field condition, little information is available on the control of postharvest roots rots. To obtain better management strategy of postharvest root rots in ginseng, biological control using antagonistic bacteria was attempted. Of 208 bacteria obtained form suppressive soil samples, 4 were selected based on the inhibitory effect on mycelial growth of two major causal fungi for postharvest root rots in ginseng, Botrytis cinerea and Fusarium solani. The culture filtrates of these bacterial antagonists greatly inhibited the conidial germination of both pathogenic fungi and produced abnormal morphology such as swollen germ tubes in F. solani and vacuolation of nongerminated conidia in B. cinerea. The population levels of bacterial antagonists on the ginseng roots were gradually increased up to 8 days of incubation. Postharvest root rots of ginseng caused by f. solani and B. cinerea were controlled in dipping tests in the ranges of 60∼80% by antagonistic Bacillus spp. obtained from suppressive soil. These results suggest that biological control using these antagonistic bacteria would be an alternative strategy to control postharvest root rots in ginseng.

• Research in Plant Disease
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• v.26 no.2
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• pp.109-115
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• 2020

A disease causing leaf blight and vine rot was recognized on kudzu plants (Pueraria lobata) in Korea since 1991. A species of Phytophthora has been repeatedly isolated from the infected leaves. Identification in species level of the Phytophthora sp. remained unsolved. An isolate, KACC 47616 originally collected from Manchon Park in Daegu, has been kept in our laboratory. In 2013, three new isolates, KACC 47617 and KACC 47618 from Yeongyang and KACC 47619 from Gunwi in Gyeongbuk province, were collected and examined to classify up to species level by characterizing morphology, response to temperature and phylogenetic relationship. On the basis of morphological characters such as the nature of hyphal swelling, sporangia and sex organs, absence of chlamydospore production, optimum temperature for mycelial growth, and internal transcribed spacer rDNA and cytochrome oxidase subunit 1 sequence analysis of the pathogen, the causal fungus of kudzu plant was identified as Phytophthora asiatica.

• Mycobiology
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• v.29 no.1
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• pp.1-6
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• 2001

Nine species of genus Ganoderma collected in Korea and abroad including Ganoderma lucidum complex and G. lucidum were compared by investigating growth characteristics. In the bottle culture, the mycelial growth periods of G. lucidum from Taiwan and North America was 26 to 30 days compared to that of Korean G. lucidum, which was 30 to 32 days. Cultivation period of Taiwan and North American isolates was 30 to 32 days which were 11 to 17 days shorter than those of Korean isolates. Biological efficiency of Taiwan and North American isolates were ranged from 3.3 to 5.5%, which were apparently lower than that of Korean isolates which ranged from 6.2 to 9.4%. Korean isolates had longer stipes($15{\sim}40$ mm) and more number of pileus($4{\sim}6$/bottle) than those of Taiwan and North American isolates. The G. lucidum isolates collected from Korea will be regarded as the independent species from the G. lucidum collected from Taiwan and North America since, the G. lucidum from Korea showed much different growth characteristics in various aspects compared to the G. lucidum from Taiwan and North America.

• 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.

• The Plant Pathology Journal
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• v.18 no.3
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• pp.142-146
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• 2002

The effect of potassium phosphonate ($KH_2PO_3 or $K_2 HPO_3$) on the control of Phytophthora root rot of lettuce was evaluated in a liquid hydroponic culture. Phosphonate 100 ppm strongly inhibited mycelial growth of Phytophthora species in vitro but did not affect normal growth of lettuce in a greenhouse test. Application of the chemical before infection showed over 94% control value, while it was less than 35% when applied after infection. In a field trial, phosphonate 100 ppm, which was directly supplemented into the nutrient solution, satisfactorily controlled the disease as it did not develop until 28 days after transplanting and remained at less than 2% infection rate at the end of cultivation. Meanwhile, in the control plot, the disease initiated at 7 days after transplanting and developed rapidly reaching over 70% infection rate at 28 days. Population density of the causal pathogen, R drechsleri, in a heavily infested farm was 22.0-25.0 cfu/100 ml of nutrient solution. However, it decreased to 1.3-2.0 cfu/100 ml at 7 days after treatment with phosphonate 200 ppm.

• The Plant Pathology Journal
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• v.27 no.2
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• pp.120-127
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• 2011

While many isolates of Alternaria alternata are common saprophytes on trees and shrubs, this study clearly demonstrated that A. alternata is a primary pathogen in lilac (Syringa sp.), causing a leaf-blight that affects different Syringa species. Isolates of Alternaria sp. were collected from leaf blight samples of lilacs in the field. The internal transcribed spacer (ITS) region and morphological characterization were used to identify lilac blight pathogen. Based on 100% ITS nucleotide sequence identities to the Alternaria genus in the GenBank and morphological features, these isolates were identified as A. alternata. Disease symptoms were reproduced in lilac plants inoculated with A. alternata mycelial plugs and sprayed with a fungus-free culture filtrate, indicating that pathogenesis in lilac involves secondary metabolites or toxins. Diagnostic primers were developed to detect Alternaria sp. and A. alternata in lilac leaf blight based on ITS region and four known genes associated with pathogenesis in A. alternata: mixed-linked glucanase precursor, endopolygalacturonase, hsp70, and histone genes. The results from our study indicated A. alternata is a primary pathogen in lilac leaf blight, and these diagnostic primers can be used as a tool for the fast detection of A. alternata associated with lilac leaf blight.