• 한국식물병리학회지
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• 제13권1호
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• pp.1-4
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• 1997

Viroid-like RNA molecules were detected from the low molecular weight RNAs isolated from the Korean peonies which showed typical viroid symptoms of epinasty and dwarfing. Low molecular weight RNAs including viroid RNA molecules were purified by the Qiagen anion exchange minicolumns. Viroid-like RNA molecules showed a single viroid specific band in the native polyacrylamide gel. They were separated into two bands in the denaturing gel conditions. The band of circular form of viroid-like RNAs was crossed over the horizontal band of the linear form of viroid-like RNA molecules in 0~8 M urea gradient gel under the denaturing conditions of 37$^{\circ}C$. The two circular forms of viroid-like RNA molecules were detected in the reverse polyacrylamide gel electrophoresis. The viroid-like RNA molecules purified from the peonies were supposed to be unidentified viroid RNA molecules.

• 한국식물병리학회지
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• 제1권3호
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• pp.199-206
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• 1985

바이로이드(viroid)는 그의 완전한 분자구조가 처음으로 밝혀진 식물병원체이며, coat-protein이 제거된 viral-RNA가 아닌 바이로이드로서의 독립적인 특성과 병원성을 가진 작은 크기의 병원체임이 밝혀짐으로써 미생물의 영역을 한 단계 넓혀서 생각하도록 하였다. 일반적으로 생각되는 미생물 즉 곰팡이, 세균, 마이코플라스마, 바이러스들이 동물과 식물 및 인체에 병원체로서 작용하는데 바이로이드는 현재까지 고등식물에서만 발견되는 병원체이다. 다라서 바이로이드가 동물 및 인체에서 아직까지 밝혀지지 않고 있는 병의 병원체일 가능성이 있으므로 이에 대한 연구가 계속되고 있다. 바이로이드는 작은 크기임에도 독자적인 자기증식을 하는 능력과 생존을 유지하는 특성이 있기 때문에 이들의 분자구조 및 생물적 특성을 연구하는데 좋은 자료가 되며, 최근에 급속한 진전을 보이고 있는 분자생물학 및 유전공학적인 방법과 기술을 이용하여 Viroid의 여러 가지 성질과 생물학적인 위치에 대한 연구가 활발히 진행되고 있다. 앞으로 연구가 계속되어 Viroid의 증식과 병원성에 대한 문제가 해결된다면, 바이로이드병의 예방이나 치료법이 확립된 것이며 또한 목적하는 유전자를 운반하는 Vector로 개발하여 생물공학 분야에 적극적으로 활용할 수 있을 것이다.

• The Plant Pathology Journal
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• 제18권6호
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• pp.342-344
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• 2002

Apple scar skin viroid (ASSVd) has been one of the most destructive diseases in Korean apple orchards. Symptoms of the scar skin viroid disease were detected in various apple cultivars, namely, Sansa, Fuji, Chukwang, Miki-Life, Hongro, and Songbongeum cultivated in the southern part of Korea. The RNA molecules were extracted from the apples bearing dapple apple symptoms with the application of CF-11 RNA extraction method. The purified RNAs were used for the synthesis of cDNA with RT-PCR. The PCR products were cloned and sequenced. The viroid RNA molecules from the six different cultivars bearing the dapple symptos showed the same nucleotide sequences as that of the Korean strain of ASSVd（ASSVd-K). ASSVd-K was detected from apple orchards in Kunwi, Sangju, Uiseong, Yeong-yang, Andong, and Youngduk in Gyeongbuk Province in 2001, and in Muju in Jeonbuk Province in 2002. As the viroid disease could be propagated vegetatively, it can be widely transmitted gradually in Korea.

• The Plant Pathology Journal
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• 제35권2호
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• pp.164-171
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• 2019

An assay for detecting Apple scar skin viroid (ASSVd) was developed based on nucleic acid sequence based amplification (NASBA) in combination with realtime detection during the amplification process using molecular beacon. The ASSVd specific primers for amplification of the viroid RNA and molecular beacon for detecting the viroid were designed based on highly conserved regions of several ASSVd sequences including Korean isolate. The assay had a detection range of $1{\times}10^4$ to $1{\times}10^{12}$ ASSVd RNA $copies/{\mu}l$ with reproducibility and precision. Following the construction of standard curves based on time to positive (TTP) value for the serial dilutions ranging from $1{\times}10^7$ to $1{\times}10^{12}$ copies of the recombinant plasmid, a standard regression line was constructed by plotting the TTP values versus the logarithm of the starting ASSVd RNA copy number of 10-fold dilutions each. Compared to the established RT-PCR methods, our method was more sensitive for detecting ASSVd. The real-time quantitative NASBA method will be fast, sensitive, and reliable for routine diagnosis and selection of viroid-free stock materials. Furthermore, real-time quantitative NASBA may be especially useful for detecting low levels in apple trees with early viroid-infection stage and for monitoring the influence on tree growth.

• The Plant Pathology Journal
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• 제22권3호
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• pp.235-238
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• 2006

Chrysanthemum stunt viroid (CSVd) induced systemic symptoms on chrysanthemum. We detected small RNAs of approximately 22 nucleotides with sequence specificity to CSVd in chrysanthemum infected with CSVd: an indication of the presence of RNA silencing. Regardless of symptom differences associated with CSVd, the small RNAs distributed similarly in amount. Small RNAs were detected with partial-length or full-length probes, indicating that they are not restricted to specific viroid regions but likely representing most of the viroid molecule.

• The Plant Pathology Journal
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• 제24권3호
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• pp.305-308
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• 2008

A viroid was detected from symptomless Coleus blumei cultivar 'Kong Scarlet'. It consisted of 249 nucleotides(GenBank accession no. EU410620), which was 100% identical to a Coleus blumei viroid 1(CbVd 1) reported from China(GenBank accession no. DQI78399), indicating that the viroid was an isolate of CbVd1. Attempts were made to determine if commercial Coleus seeds were infected with CbVd. Infection rates in seedlings of the 14 commercial cultivars of Coleus ranged from 0 to 100%. CbVd1 caused discoloration and growth retardation in some cultivars, but is symptomless in others. These results indicated that Coleus in commercial markets in Korea is highly infected with CbVd.

• 한국식물병리학회지
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• 제13권2호
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• pp.113-117
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• 1997

Low moleuclar weight (LMW) RNAs were isolated form Korean peonies which expressed symptoms of stunt and epinasty. The LMW plant RNAs were purified by Qiagen column chromatography which could separate viroid specific nucleic acid at differential salt concentration. After the inoculation of the purified RNAs from the peonies, the inoculated tomatoes (cv. Rutgers) expressed the symptoms of stunt and epinasty. Also the same molecular weight RNAs with viroid-like RNAs were isolated from the inoculated tomatoes. Double-stranded cDNA were synthesized by the methods of reverse transcription (RT) and polymerase chain reaction (PCR) with the purified RNA and primers. The same cDNAs associated with viroid-like RNAs wre cloned from the inoculated tomatoes. The cDNA has been sequenced and its 375-nucleotides were arranged into secondary structure. The cloned cDNA showed 47~54% homology compared with other viroids. The sequence homology of the cloned cDNA were partially high with plant genomic RNAs.

• Journal of Plant Biotechnology
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• 제42권1호
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• pp.43-48
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• 2015

바이로이드에 감염된 과수의 생산성 하락으로 인한 농업인의 소득이 점점 감소하고 있는 실정이다. 감에 감염이 가능한 바이로이드는 PVd(Persimmon viroid)와 CVd(Citrus viroid) 등이 존재하는 것으로 알려져 있다. 따라서 본 연구에서는 전라남도 감 재배 농가에서의 감 바이로이드 감염 현황을 확인하였고 열처리, 한냉처리, 항바이러스제 처리를 통해 무병화 효율성을 알아보았다. 전라남도 나주, 영암, 담양, 순천, 구례의 20농가에서 감 부유 품종 198개체를 샘플링하였다. RT-PCR 실험을 통해 감 바이로이드의 감염률을 확인해 본 결과 CVd 41%, PVd 34% 로 확인되었으며 이미 알려진 수준에 비해 높게 감염되어 있음을 알 수 있었다. 무병화 효율 실험은 PVd와 CVd가 감염된 감을 이용하였으며 처리 방법에 따라 열처리($38^{\circ}C$), 한냉처리($4^{\circ}C$), 항바이러스제(Ribavirin) 단독 처리 그룹과 열처리와 항바이러스제를 동시에 처리한 그룹 및 한냉처리 및 항바이러스제를 동시에 처리한 그룹으로 나누었으며 처리 시간에 따라 2주와 4주로 나누어 각각의 바이로이드 제거 효율을 확인하였다. 한냉 처리한 그룹의 경우 생존율이 100%에 무병화 효율 또한 67%의 높은 제거 효율을 확인할 수 있었고, 한냉 처리와 항바이러스제를 2주간 복합처리한 군에서도 67%의 높은 효율을 확인하였다. 결론적으로 한냉 처리가 가장 높은 무병화율을 보여 주었으며 본 연구결과를 통해 감 무병화 연구에 좋은 자료가 될 것으로 판단된다.

• The Plant Pathology Journal
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• 제17권5호
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• pp.300-304
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• 2001

Apple is the most economically important fruit in Korea. The suspected viroid disease of dapple apple was found in apple fruits cultivated in Kyungpook province. Symptoms begin in mid-July as small circular spots, which stand out against the background color on the young fruit. Dappling of the fruit becomes more intense and easier to detect as the fruit approaches maturity; the affected spots remain yellowish as the fruit matures. no leaf or bark syndromes have been associated with this disease. The infected fruits are downgraded considerably during quality grading. The low molecular weight RNA containing viroid RNA molecules were extracted from the peels of the apples with dapple symptoms. The RNA molecules were extracted from the apples using Qiagen column chromatography. The purified RNAs were used for the synthesis of cDNA with RT-PCR. The PCR products were then ligated into a pGEM-T Easy vector, cloned and sequenced. The sequence of the viroid RNA molecule shows 331 nucleotides with one base difference ("G" insertion between the position of 133 and 134) compared with that of the Apple scar skin viroid (ASSVd) reported by Hashimoto and Koganezawa in Japan. This is the first report on the occurrence of the ASSVd in apple trees cultivated in Korea, as well as the identification of a new Korean strain of the ASSVd.the ASSVd.

• 미생물학회지
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• 제25권1호
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• pp.23-27
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• 1987

바이로이드 RNA 분자를 포함한 저분자량의 식물성 RNA 분자에 대해서 0M부터 8M 까지의 요소구배를 가진 폴리아크릴아미드켈을 이용하여 전기영동적 이동성을 조사하였다. 막대모양의 바이로이드 RNA 분자는 요소구배 겔에서 전반적으로 다른 저분량의 식물성 RNA들과 마찬가지로 요소구배에 수직인 방향으로 비슷한 수준의 전기영동적 이동성을 보여주었다. 이와 달리 고리모양의 바이로이드 RNA 분자는 요소구배 겔에서 고농도의 요소구배 부분에서 보다도 저 농도의 요소구배 부분에서 더 빠르게 이동하였다. 따라서 고리모양의 바이로이드 RNA 분자는 요소구배 겔의 중간부분에서 막대모양의 바이로이드 분자의 밴드를 가로 지르는 기울기를 가진 특이한 전기영동적 이동을 나타내었다. 결과적으로 고리모양의 바이로이드 RNA 분자의 전기영동적 이동성은 0M 8M의 요소구배를 가지는 바이로이드 RNA 분자의 변성겔에서 주로 요소의 농도에 따라서 영향을 받는 것으로 보인다.