• The Plant Pathology Journal
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• v.19 no.6
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• pp.284-287
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• 2003

Potato tubers with scab lesions were found in several regions of Gangwon province in Korea during disease surveys in 2000 and 2001. The lesions appeared as shallow scabs with torn and raised skin around the periphery of the lesion. Sometimes the lesions expanded on tuber surface and formed hollowed-out areas. The causal organism was identified as Spongospora subterranea based on morphological characteristics using light and electron microscope. Ten cultivars of potato were evaluated to select resistant cultivars against powdery scab. Among the 10 cultivars, Jowon, Superior, and Atlantic were resistant, while Sephody, Gawon, and Irish Cobbler were susceptible to powdery scab. In the pathogenicity test, typical symptoms of powdery scab were formed on potato tubers, and galls developed on root hairs. This is the first report of powdery scab of potato caused by S. subterranea in Korea.

• Proceedings of the Microbiological Society of Korea Conference
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• 2005.05a
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• pp.162-165
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• 2005

Potato scab, an important disease that affects developing tubers, causes a major problem in potato cultivation. The major potato cultivation areas in Korea are located in two Northern provinces, Gangwon and Gyeonggi, and two Southern provinces, Jeju island, and South Jeolla. In these areas, potato scab is widely distributed and has caused severe problem in potato cultivation. Therefore, potato-growing areas were surveyed for identification and distribution of potato scab pathogens from 1996 to 1999. Pathogenic Streptomyces strains were isolated from potato scab lesions and six representative Streptomyces species were characterized based on their phenotypic and molecular characteristics including, pathogenicity, physiological and morphological properties, analyses of 16SrRNA genes and 16S-23S ITS region, DNA relatedness, production of thaxtomin A, and the presence of nec1 and ORFtnp gene homologs. Three species were identified as previously described Streptomyces scabies, S. turgidiscabies, and S. acidiscabies, while other three species having distinct phenotypics properties were identified as novel S. luridiscabiei, S. puniciscabiei, and S. niveiscabiei.

• Korean Journal of Organic Agriculture
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• v.22 no.4
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• pp.719-730
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• 2014

This study was conducted to select proper soil amendments in order to reduce the occurrence of potato scab and maintaining soil health by applications of dolomitic lime, sulfur, potassium sulfate, shell meal fertilizer, silicate fertilizer, lime nitrogen and ammonium sulfate fertilizer in different pH levels of volcanic ash soil with continuous cultivation of potato. In potassium sulfate-applied plot with a low soil pH, the incidence rate and disease severity of scab were lowest at 84.4% and 28.4%, respectively. Those were lowest among the treatments. Value of potato scab control was 12.3% and marketable yield of potato was highest at 93.2%. In lime nitrogen-applied plot (60 kg/10a), the incidence rate was low at 38.3%, and control value was 23.8% and marketable yield of potato was high at 66.3%. In relatively higher pH soils, the incidence rate of scab was lowest at 38.3% in the lime nitrogen-applied plot (60 kg/10a). Value of potato scab control was 23.8%, which was four times higher than that in sulfur-applied plot. Marketable yield of potato was highest at 66.3% in the lime nitrogen-applied plot. In the lime nitrogen plot infected with potato scab pathogen such as S. acidiscabies and S. scabiei were remarkably lower than other soil amendments at 2.5, 5, and 10 g/L concentrations of lime nitrogen using Glucose Yeast Malt (GYM) medium. In conclusion, this study suggests that potassium sulfate application in low pH soil (less than pH 5) and lime nitrogen application in relatively higher pH soil (more than pH 6) before potato seeding might be helpful to reduce the occurrence of potato scab.

• The Plant Pathology Journal
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• v.18 no.6
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• pp.338-341
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• 2002

The potato scab is caused by several species of Streptomyces. Among these species, only pathogenic strains were found to produce thaxtomin A characterized by necrotic bioassay and HPLC. In this study, identification of the pathogenic strains of Streptomyces was performed through the polymerase chain reaction (PCR) by using specific pathogenicity primer sets derived from the nec1 gene sequences of Streptomyces scabies. The expected PCR products were obtained approximately 580 bp and confirmed by sequencing. This PCR technique can be used effectively to identify the pathogenic Streptomyces species, that cause scab on potato tubers.

• Korean Journal of Microbiology
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• v.54 no.2
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• pp.158-160
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• 2018

Streptomyces sp. P3 was isolated from potato scab diseased tubers in Pyeongchang, Gangwon-do, Republic of Korea in 2017. Here, we report the draft genome sequences of P3 with 9,851,971 bp size (71.2% GC content) of the chromosome. The genome comprises 8,548 CDS, 18 rRNA and 66 tRNA genes. Although strain P3 did not show pathogenicity both potato tuber assay and radish seedling assay, it possesses tomatinase (tomA) gene among conserved pathogenicity-related genes in well characterized pathogenic Streptomyces. Thus, the genome sequences determined in this study will be useful to understand for pathogenic evolution in Streptomyces species, which already adapted to potato scab pathogens.

• Microbiology and Biotechnology Letters
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• v.35 no.4
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• pp.347-351
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• 2007

Potato scab is prevalent in all potato-growing areas of Jeju Island and causes economically significant losses. Streptomyces species are known as pathogens of potato scab. In this study, we analyzed the 16S rRNA sequences of Streptomyces spp, which are isolated from potato scab lesions in Jeju Island, and constructed 16S rRNA phylogenetic tree. All isolates were clearly differentiated into the genus Streptomyces, and the tree also showed that new scab-causing Streptomyces spp or not yet named species of Streptomyces are existed in Jeju Island, Korea.

• Research in Plant Disease
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• v.10 no.2
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• pp.135-137
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• 2004

It was conducted to select the resistant potato cultivars to common scab, to replace the existing susceptible cv Dejima in Jeju island conditions both 1997 and 2001. Among cultivars, cvs Jemchip, Alpa, Atlantic and Jopung were more resistant than others in the field with both low and high incidence of the disease. Also among the existing cultivars grown in Korea, cvs Superior, Jopung and Chubaek were resistant, expecially in terms of production of marketable potatoes.

• The Plant Pathology Journal
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• v.20 no.2
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• pp.110-114
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• 2004

Through in vitro screening for biocontrol agents (BCAs) against Streptomyces scabiei causing potato (Solanum tuberosum) common scab, 19 streptomycete and 17 fungal isolates with antagonistic activity were selected as BCA candidates. For the selection of BCA candidates which are highly resistant to 10 kinds of antibiotics or pesticides, chemical susceptibility testing was initially performed in vitro. A remarkable degree of variation in susceptibility to antibiotics or pesticides was observed among the isolates tested. Streptomycete A020645 isolate was highly resistant to all the tested chemicals except neomycin up to 5,000 ppm. On the other hand, out of 36 antagonistic microbes subjected to in vivo pot tests using cultivar Daejima, four streptomycete isolates namely, A020645, A010321, A010564, and A020973, showed high antagonistic activity with >60% and 55% control value, respectively, and high chemical resistance to 10 kinds of chemicals. Therefore, these isolates were selected as potential BCAs for the control of potato common scab.

• Korean Journal Plant Pathology
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• v.14 no.5
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• pp.551-554
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• 1998

Bacterial specs isolated from common scab lesion on potato (Solanum tuberosum L. c.. Dejima) tuber was identified as Streptomyces turgidiscabies. This organism had flexuous spore chains and grey spore mass color, produced melanin pigment on ISP 7, but did not produce on ISP 6. S. turgidiscabies grew on agar media at pH 4.5, used L-arabinose, D-fructose, D-glucose, D-mannitol, raffinose, rhamnose, sucrose, D-xylose and meso-inositol as carbon sources, and was susceptible to 7% NaCl, thallium acetate (10 $\mu\textrm{g}$/ml, 100$\mu\textrm{g}$/ml), crystal violet (0.5 $\mu\textrm{g}$/ml), phenol (0.1%, wt/vol), oleandomycin (100 $\mu\textrm{g}$/ml), and streptomycin (20 $\mu\textrm{g}$/ml).

• Korean Journal Plant Pathology
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• v.14 no.6
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• pp.689-692
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• 1998

Bacterial species isolated from common scab lesion on potato (Solanum tuberosum L. cv. Dejima) was identified as Streptomyces acidiscabies. This organism had flexuous spore chains and white spore mass color, produced melanin pigment on tyrosine agar medium but did not produce on peptone agar medium. S. acidiscabies grew on agar medium at pH 4.0, used L-arabinose, D-fructose, D-glucose, D-mannitol, rhamnose, sucrose, D-xylose and meso-inositol except reffinose as carbon sources. It was also susceptible to thallium acetate (10 $\mu\textrm{g}$/ml, 100$\mu\textrm{g}$/ml), phenol (0.1%, wt/vol), streptomycin (20 $\mu\textrm{g}$/ml), and was resistant to 7% NaCl, crystal violet (0.5 $\mu\textrm{g}$/ml), penicillin (10 IU/ml) and oleandomycin (25 $\mu\textrm{g}$/ml, 100 $\mu\textrm{g}$/ml).