• Mycobiology
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• 제28권4호
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• pp.190-192
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• 2000

Antifungal bacteria for biological control of plant diseases or production of novel antibiotics to plant pathogens were isolated in 1997 from various soils of Ansung, Chunan, Koyang, and Paju in Korea. Sixty-four bacterial strains pre-screened from approximately 1,400 strains were tested on V-8 juice agar against eight plant pathogenic fungi using in vitro bioassay technique for inhibition of mycelial growth. Test pathogens were Alternaria mali, Colletotrichum gloeosporioides, C. orbiculare, Fusarium oxysporum f. sp. cucumerinum, F. oxysporum f. sp. lycopersici, Magnaporthe grisea, Phytophthora capsici, and Rhizoctonia solani. A wide range of antifungal activity of bacterial strains was found against the pathogenic fungi, and strain RC-B77 showed the best antifungal activity. Correlation analysis between inhibition of each fungus and mean inhibition of all eight fungi by 64 bacterial strains revealed that C. gloeosporioides would be best appropriate for detecting bacterial strains producing antibiotics with potential as biocontrol agents for plant pathogens.

• 한국동물위생학회지
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• 제45권3호
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• pp.191-199
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• 2022

We investigated the virulence genes, O-serotypes, antimicrobial resistance of pathogenic E. coli isolated from carcasses (n=455) and environmental (n=372) samples of 11 cattle and 12 pig slaughterhouses from December 2020 to December 2021. E. coli were isolated from nine carcasses (2.0%), three slaughter facilities (1.4%), two utensils (2.7%) and three abattoir workers (3.5%) from four cattle and four pig slaughterhouses. Among all isolates, 13 STEC (76.5%) were identified, followed by four EPEC (23.5%). As a result of the antibiotic susceptibility test, all isolates were resistant to at least one antimicrobial, of which 70.6% isolates showed multidrug resistance patterns. The serotypes were diverse in pigs compared to cattle, with serotypes O18, O66, O109 in cattle and O9, O76, O85, O100, O153, and O159 in pigs. In a single cattle slaughterhouse, eight STEC O66 were isolated from various types of sample (4 slaughter animal surfaces, 3 gloves, and 1 knife) with two antimicrobial resistance patterns (CHL-FIS-STR and CHL-FIS). Those two types of strain were suspected cross-contamination from utensils to slaughter animal surfaces. These results showed that pathogenic E. coli were detected in carcasses and various environmental samples in cattle and pig slaughterhouses. Nationwide monitoring and hygiene management are required to prevent cross-contamination of STEC isolate slaughterhouses.

• The Plant Pathology Journal
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• 제26권3호
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• pp.209-215
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• 2010

Plant pathogenic oomycetes, such as Phytophthora spp., are the causal agent of the most devastating plant diseases. During infection, these pathogens accomplish parasitic colonization of plants by modulating host defenses through an array of disease effector proteins. These effectors are classified in two classes based on their target sites in the host plant. Apoplastic effectors are secreted into the plant extracellular space, and cytoplasmic effectors are translocated inside the plant cell, through the haustoria that enter inside living host cell. Recent characterization of some oomycete Avr genes showed that they encode effector protein with general modular structure including N-terminal conserved RXLR-DEER motif. More detailed evidences suggest that these AVR effectors are secreted by the pathogenic oomycetes and then translocated into the host plant cell during infection. Recent findings indicated that one of the P. infestans effector, Avrblb2, specifically induces hypersensitive response (HR) in the presence of Solanum bulbocastanum late blight resistance genes Rpi-blb2. On the other hand, another secreted RXLR protein PexRD8 originated from P. infestans suppressed the HCD triggered by the elicitin INF1. In this review, we described recent progress in characterized RXLR effectors in Phytophthora spp. and their dual functions as modulators of host plant immunity.

• The Plant Pathology Journal
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• 제38권6호
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• pp.685-691
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• 2022

Plants produce chemicals of immense diversity that provide great opportunities for development of new antifungal compounds. In search for environment-friendly alternatives to the fungicide of current use, we screened plant extracts obtained from more than eight hundred plant materials collected in Korea for their antifungal activity against the model plant pathogenic fungus, Magnaporthe oryzae. This initial screening identified antifungal activities from the eleven plant extract samples, among which nine showed reproducibility in the follow-up screening. These nine samples were able to suppress not only M. oryzae but also other fungal pathogens. Interestingly, the plant extracts obtained from Actinostemma lobatum comprised five out of eight samples, and were the most effective in their antifungal activity. We found that butanol fraction of the A. lobatum extract is the most potent. Identification and characterization of antifungal substances in the A. lobatum extracts would provide the promising lead compounds for new fungicide.

• 한국응용곤충학회지
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• 제14권3호
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• pp.155-161
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• 1975

본 실험은 Corynebacterium속 식물병원세균에 관한 연구의 일환으로서 Corynebacterium속 식물병원세균의 종 및 속으로서의 특성을 구명함과 동시에 C. sepedonicum이 생성하는 Rumiflabin에 기초를 둔 ultraviolet method의 재검토를 위하여 행하여 진 것으로 vitamin B군의 정량은 미생물 정량에 의하였다. 대다수의 식물병원세균은 Thiamine (vitamin $B_1$), Nicotinic acid, Biotin 및 안식향산을 생장물질로서 사용하였다. Riboflavin은 corynebacterium속 식물 병원세균 (C. rathay 및 C. fascians는 제외)은 물론 타속의 식문병원세균도 생성하는 점으로 Corynebacterium속 식물병원 세균의 특성이 아니라는 점이 구명되었으며 sepedonicum에 의하여 발생되는 감자의 윤부병과 청고병과의 감별에 사용되어온 Ultra-violet light법은 재검토되어야 한다.

• 한국식물병리학회지
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• 제14권4호
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• pp.303-307
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• 1998

Citrus scab caused warty and scabby lesions on the surface of leaves, twigs and fruits of Satsuma mandarin. Warty lesions were mainly developed before July but scabby ones were developed during summer season in Cheju island, Korea. The casual organism of scab was morphologically identified as Sphaceloma fawcettii and was thought to be Tryon's pathotype of Elsinoe fawcettii, because it was pathogenic on rough lemon and Cleopatra mandarin but non-pathogenic on sour orange, grapefruit and sweet orange among the 5 differential hosts of E. fawcettii.

• Advances in Traditional Medicine
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• 제6권4호
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• pp.306-311
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• 2006

This communication emphasized upon the sensitivity of the crude extracts of clerodendrum inerme against some of the human pathogenic bacteria. Five plant extracts (Petrol, Benzene, Methanol, Ethly acetate and Aqueous) under six different concentrations(500 ${\mu}g/ml$, 1 mg/ml, 2 mg/ml, 5 mg/ml, 10 mg/ml and 15 mg/ml) were tested by disk diffusion method. Methanol, Ethyl acetate and Aqueous extracts of the plant showed significant inhibition against fifteen of the eighteen bacteria tested. No earlier report on antibacterial activity of this taxon could be found in literature.

• The Plant Pathology Journal
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• 제16권6호
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• pp.331-334
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• 2000

Alternaria helianthi and two unreported species of Alternaria in Korea were isolated from lesions of Alternaria leaf spot disease of sunflower. The unrecorded species of Alternaria were identified as A. helianthinficients and A. protenta based on the morphological characteristics of conidiophores and conidia. A. helianthi was the dominant species, although all the three species were associated with the disease. A. helianthi, A. helianthinficiens and A. protenta produced similar symptoms on detached sunflower leaves. This is the first report of A. helianthinficiens and A. protenta pathogenic on sunflower in Korea.

• 생명과학회지
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• 제14권6호
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• pp.1003-1008
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• 2004

11 plant essential oils are screened in vitro for their antifungal activities against Botrytis cinerea, Fusarium oxysporum and Rhizoctonia solani, which are causative agents of serious plant diseases. The radial growth of the test fungi were reduced in response to the oils. Among them, the essential oil from the bark of Cinnamomum zeylanicum inhibited 3 tested fungi growth, strongly, followed by those of oregano and thyme. The major constituents of the three essential oils, cinnaldehyde, carvacrol and thymol were tested for their effects on the fungi. From the results obtained, cinnamaldehyde, the major constituents of C. zeylanicum bark esential oil, has potential to be developed as a biopesticide for controlling phytopathogenic fungi causing serious damages on the important crops cultivated in Korea.

• The Plant Pathology Journal
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• 제17권5호
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• pp.311-314
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• 2001

Phytophthora root rot of lettuce, which has not been reported in Korea before, occurred severely in liquid hydroponic culture. The disease occurred in all seasons and was most severe in summer from June to August, showing over 90% infection rate in some farms. A total of 51 isolates collected from various farms were all identified as Phytophthora drechsleri. The fungus showed strong pathogenicity to lettuce and Chinese cabbage, moderate pathogenicity to cucurbits and tomato, and weak pathogenicity to pepper. However, the fungus was not pathogenic to other leafy vegetables namely: chicory, kale, endive, garland chrysanthemum, spinach beet, and perilla. Among 10 species of Phytophtora inoculated to lettuce, only P. drechsleri and P. cryptogea were found pathogenic.